Article

Impact of cattle dung deposition on the distribution pattern of plant species in an alvar limestone grassland

October 2000
Journal of Vegetation Science 11(5):715 - 724

October 2000
11(5):715 - 724

Authors:

Seed banks in cattle dung, soil under cattle dung and soil under vegetation and growth response of plant species to the changes in soil nitrogen availability were studied in an alvar limestone grassland on Öland, Sweden, in order to analyse the impact of dung deposition and decomposition on the formation of patches of plant species. Results suggest that patches of four plant species could result from cattle dung deposition and decomposition. Impact of dung could proceed in three ways: (1) by changing the relative abundance of species in the soil seed bank under dung, and/or (2) by influencing the deposition of seeds in the dung, and/or (3) by intensifying the growth of some species through nutrient release. Species patches could result from one or more of these aspects. For instance, patches of Arenaria serpyllifolia may be induced by dung deposition because of the dominance of its seeds in dung, while the pattern of Cerastium semidecandrum and Festuca ovina may be due to the abundance of their seeds in the soil seed bank under dung and their positive growth response to increased nitrogen availability.

Wildfire and cattle legacies on gradients of soil nitrogen underlie patterns of annual brome invasion

Article

Full-text available

Oct 2023
OECOLOGIA

Human activities are increasing wildfires and livestock activity in arid ecosystems with potential implications for the spread of invasive grasses. The objective of this study was to test whether fire history and cattle activity alter soil resource gradients, thereby affecting patterns of Bromus rubens L. (red brome) invasion. Six paired burned and unburned transect lines (1-km long) were established in the northeast Mojave Desert along the boundaries of four independent wildfire scars. At 100-m transect increment points, we measured the distance to the two nearest cowpats, and two random points and measured the density, height, biomass, and seed production of red brome, soil moisture and inorganic nitrogen (N). Cattle activity was 29% greater along burned transects compared to unburned transects (P < 0.05). Red brome height, density, and seed production were 11–34% greater along burned transects than unburned transects (P < 0.05). Red brome height, biomass, density, and seed production were twofold to tenfold greater next to cowpats compared to random points (P < 0.05). Soils along burned transects and beneath cowpats had greater soil inorganic N (P < 0.05), which was positively correlated with red brome density, height, biomass, and seed production (R2 = 0.60–0.85, P < 0.0001). Transgenerational effects were evident as seeds from red brome next to cowpats had 27% higher germination than seeds collected from random points. Positive responses of red brome to increased inorganic N related to fire and cattle activity may contribute fine fuel infill that drives invasive grass-fire cycles in deserts.

European exotics drive a North American invasion: fire and cattle legacies on soil resource gradients and patterns of annual brome invasion

Preprint

Full-text available

Oct 2022

Human activities alter disturbance regimes and spatio-temporal distribution of soil resources that can affect plant invasion outcomes. The objective of this study was to test whether fire history and cattle activity alter soil resource gradients, thereby affecting patterns of annual brome invasion. Six paired burned and unburned transect lines (1-kilometer in length) were established in the northeast Mojave Desert along the boundaries of four independent wildfires. At 100-meter transect increment points, we measured the distance to the two nearest cowpats and then established two random points and measured the density, height, biomass, and seed production of red brome, soil moisture and inorganic N. Cattle activity was 29% greater along burned transects compared to unburned transects. Red brome height, density, and seed production were 11% to 34% greater along burned transects than unburned transects (P < 0.05). Red brome height, biomass, density, and seed production were 2- to10-fold greater next to cowpats compared to random points (P < 0.05), likely due to increased soil moisture and inorganic N. Post-fire conditions and cowpats increased soil inorganic N, which was strongly correlated with red brome density, height, biomass and seed production (R ² = 0.60-0.85). Transgenerational legacy effects were evident as seeds from red brome next to cowpats had 27% higher germination than seeds collected from random points. The results suggest that positive responses of red brome to increases in inorganic N related to fire and cattle activity could significantly reinforce fine fuel infill that drives invasive grass-fire cycles in deserts of North America.

Yak dung pat fragmentation affects its carbon and nitrogen leaching in Northern Tibet, China

Article

Apr 2021
AGR ECOSYST ENVIRON

The dung excreted by yaks (Bos grunniens) into alpine grasslands on the Qinghai-Tibetan Plateau is an important ecological pathway for returning organic matter and nutrients that are closely linked to soil fertility and grassland productivity. However, few previous studies have investigated the dynamics of carbon (C) and nitrogen (N) associated with yak dung pats, particularly with respect to C and N leaching. This study experimentally investigated the effects of yak dung pat fragmentation on its C and N dynamics in Northern Tibet. Four treatments were examined: a full-size dung pat (control, FDP) and respectively splitting the full-size dung pat into four (1/4FDP), eight (1/8FDP), and sixteen (1/16FDP) equal-sized pats, each within an identical leaching device and had three replicates. The results showed that fragmentation did not influence (P > 0.05) dung total organic C (TOC) and N (TN) concentrations, but it did cause a decrease (P < 0.05) in both ammonium-N (NH4⁺-N) and nitrate-N (NO3⁻-N) concentrations and also reduced the loss of dry matter (P < 0.05), after 72 days of dung decomposition. Cumulative amounts of dissolved organic C (DOC) and N (DON) leached from the dung were significantly higher in the three fragmentation treatments than in the control (respectively 2.46–3.50 vs. 1.64 g C chamber⁻¹, 0.14–0.16 vs. 0.10 g N chamber⁻¹; P < 0.05). However, fragmentation did not always decrease cumulative dung NH4⁺-N and NO3⁻-N leaching, and neither NH4⁺-N nor NO3⁻-N leaching (P > 0.05) were affected by the 1/4FDP treatment. The DOC leaching accounted for 1.58–3.36 % of the initial dung TOC input, while the DON, NH4⁺-N, and NO3⁻-N leaching respectively accounted for 2.34–3.82 %, 0.68–0.87 %, and 0.19–0.27 % of the initial dung TN input. In conclusion, our findings suggest that yak dung pat fragmentation can increase the leaching of DOC and DON and the heavily fragmenting can decrease the leaching of both NH4⁺-N and NO3⁻-N after short-term dung decomposition in Northern Tibet.

Impacto de los cúmulos de estiércol de caballos cimarrones sobre la flora de una reserva de pastizal pampeano

Thesis

Full-text available

Sep 2005

Alejandro Loydi

EFFECTS OF GRAZING INTENSIFICATION AND ABANDONMENT ON THE COMPOSITION, DIVERSITY AND FUNCTIONING OF MEDITERRANEAN GRASSLANDS.

Thesis

Full-text available

Nov 2012

Carlos P. Carmona

Dissecting the Effects of Simulated Cattle Activity on Floristic Composition and Functional Traits in Mediterranean Grasslands

Article

Full-text available

Nov 2013
PLOS ONE

Livestock exerts direct and indirect effects on plant communities, changing colonization and extinction rates of species and the surrounding environmental conditions. There is scarce knowledge on how and to what extent these effects control the floristic and functional composition of plant communities in grasslands. We performed an experiment that included several treatments simulating trampling, defoliation, faeces addition and their combinations in a Mediterranean scrub community grazing-abandoned for at least 50 years. We monitored the plots for four years, and collected data on species composition, photosynthetically active radiation (PAR) and red∶far-red ratio (R∶FR), soil moisture and compaction. We estimated community weighted means (CWM) for height, habit, life cycle, seed mass and SLA. Neither compaction nor soil moisture were modified by the treatments, while PAR and R∶FR increased in all treatments in comparison to the Control and Faeces treatments. The floristic composition of all treatments, except for Faeces, converged over time, but deviated from that of the Control. The functional traits displayed the trends expected in the presence of grazing: loss of erect species and increased cover of short species with light seeds, with rosettes and prostrate habit. However, contrary to the results in literature, SLA was lower in all the treatments than Control plots. Like the results for floristic composition, all treatments except for Faeces converged towards a similar functional composition at the end of the four year period. The results of this study show the initial evolution of a Mediterranean plant community in the presence of grazing, driven primarily by the destructive action of livestock. These actions seem to directly affect the rates of extinction/colonization, and indirectly affect the light environment but not the soil conditions. However, their effects on floristic and trait composition do not seem to differ, at least at the small spatio-temporal scale.

Choose Local: Dung Addition from Native Herbivores Can Produce Substantial Positive Effects on the Growth of Native Grasses Compared to Livestock Dung

Article

Full-text available

Jul 2023

Livestock grazing and dung deposition can increase soil nutrients, contributing to the dominance of exotic species. Recent research suggests that native herbivore grazing has positive effects on native vegetation and soil health. However, little is known about the effects of native herbivore dung on plant growth and its potential implications for the restoration of degraded grasslands. This study examined the effects of dung addition from a native herbivore, kangaroo ( Macropus giganteus ), and ruminant livestock, sheep ( Ovis aries ), on biomass production and nutrient uptake of the native perennial wallaby grass ( Rytidosperma auriculatum ) and the annual exotic wild oat ( Avena barbata ), two of the most abundant grasses from the temperate grasslands of southern Australia. We conducted a glasshouse experiment, adding each type of dung to each plant species grown without competition in pots containing soil with a nutrient composition similar to that of old fields. Kangaroo dung produced higher wallaby grass aboveground biomass than other treatments and less wild oat aboveground biomass than the control. Kangaroo dung affected nutrient uptake but not nutrient concentration. Sheep dung had no effect. We demonstrated that native herbivores and livestock dung can have different effects on the biomass of native and invasive grasses. The higher nutrient uptake in wallaby grass appeared to be a consequence of the higher biomass production, suggesting that the effects produced by kangaroo dung could be related to its chemical and biological characteristics rather than its nutrient composition. Incorporating native herbivores’ dung or facilitating their presence can improve restoration outcomes in degraded grasslands.

Herbivore-induced expansion of Helianthemum nummularium in grassland–scrub mosaic vegetation: circumstantial evidence for zoochory and indirect grazing impact

Article

Full-text available

Jul 2017
PLANT ECOL

Extensive grazing often has a strong influence on the structure and composition of herbaceous plant communities with increasing population sizes for some species and decreasing presence in others. Herbivores affect plant communities directly by selective grazing of plant species, and indirectly by either epizoochory or endozoochory. Helianthemum nummularium is considered an increasing species because its distribution increased after the introduction of large, free-ranging grazers in at least two coastal dune grassland areas in Belgium. However, its seeds lack any obvious adaptations for epizoochory, and direct observations of plant/seed consumption are scarce. Through field and lab experiments, we assessed the dispersal ability of H. nummularium via endozoochory and epizoochory. In a differentiated grazer exclusion experiment, evidence was found that plants are grazed by large domestic ungulates and small wild herbivores although these incidences were rare. Direct endozoochory evidence remained scarce. No seeds were found germinating in field-collected dung, and only few seedlings emerged following a seed feeding experiment. However, once deposited, we found higher growth rates when seeds were mixed with dung and decreased establishment success when seeds were sown in combination with competitively superior species. Epizoochory was plausible because both fur and hooves of cattle and horses were potentially capable of contributing to the transport of H. nummularium seeds. We conclude that herbivores play a role in seed dispersal, while their selective grazing behaviour most probably creates an appropriate environment for Helianthemum establishment and maintenance.

Reduced germination success of temperate grassland seeds sown in dung: consequences for post-dispersal seed fate

Article

Full-text available

Sep 2016
PLANT BIOLOGY

Endozoochory is one of the main drivers shaping temperate grassland communities by maintaining plant populations of its constituents and enabling plants to colonize new habitats. Successful endozoochorous dispersal implies that seeds not only get consumed and survive the digestive tract but are also able to develop into viable seedlings in a dung environment. We experimentally assessed the germination probability and timing of 15 annual and perennial temperate European grassland species in cattle and horse dung and in different climatic conditions (greenhouse and outdoor conditions). Interspecific variation in germinability and germination timing are found, while life strategy had only an effect on germination timing. We found adverse effects of both cattle and horse dung on the germination characteristics of all tested grassland species, but the effects of cattle dung were more pronounced. In comparison with the control treatment, fewer seeds emerged in dung and more time was needed to germinate. Also, germination metrics clearly differed between the artificial greenhouse and outdoor conditions, with generally a lower germinability in outdoor conditions. According to our results, a large cost seems to be associated with endozoochorous dispersal in this stage of the life cycle, as seed dispersal effectiveness strongly depends on the quality of the deposition site with a lowered survival and germination probability when seeds are deposited in dung.

Cost or benefit for growth and flowering of seedlings and juvenile grassland plants in a dung environment

Article

Full-text available

Aug 2016
PLANT ECOL

Endozoochory is a potential dispersal mode for numerous plant species. Although germination following endozoochory is well-documented, less is known about the costs and benefits associated with this dispersal mode in later life stages of established plants. The chemical and physical nature of dung differs between herbivores and might have specific effects on seedling establishment, growth and flowering. We conducted a growth experiment using 12 temperate grassland species with a known potential for endozoochory. We studied the effects of cattle and horse dung on the juvenile, growth and reproductive phase. Being a ruminant and a hindgut fermenter, respectively, cattle and horses are two physiologically contrasting herbivore species, producing structurally quite different dung types. They are additionally interesting model species as both are frequently introduced in temperate Europe grassland management. Seedling biomass and growth rate, height, ramification, flowering and biomass of grown plants were measured in an attempt to quantify the benefits of endozoochorously dispersed seeds compared to seeds dispersed by other means and thus growing in a virtually dung-free environment. Few species were affected by the presence of dung in the juvenile phase while most species generally benefitted from being deposited in dung in later life stages. Positive responses of Agrostis capillaris, Agrostis stolonifera, Alopecurus myosuroides, Helianthemum nummularium, Poa annua, Trifolium repens and Trifolium pratense were found, while dung had a negative effect on Juncus bufonius. The initial losses of viable seeds through the digestive system of herbivores might, therefore, be partially compensated by enhanced growth and flowering in some species.

Dung of domestic grazing animals: Characteristics and role for grassland function

Article

Jan 2012
PROD ANIM

Three main factors underlie the physico-chemical characteristics of domestic grazing animal dung: the species of animal, the physiological state of the animal and quality of ingested herbage (driven by plant community composition and climatic conditions). Given that animals use only a small proportion of the nutrients they ingest, dung represents significant transfers of organic matter and nutrients to the pasture, promoting spatial heterogeneity in soil nutrients and nutrient cycling via uneven returns. This heterogeneity has cascading effects on both plant and animal diversity at the local scale. Dung degradation and time to disappearance depends on both climatic factors and coprophagous invertebrate activity. These invertebrates play a key role in modifying the properties of both animal dung and soil (aeration, water porosity), which in turn promotes microbial activities. In general, large dung patches have an adverse effect on vegetation immediately below the dung, and lead to local rejection of herbage by grazing animals. In the longer term, dung has a positive effect on surrounding pasture growth which may last up to two years after dung disappearance. Whilst the chemical transformations of dung and effects on flora and fauna are relatively well-described, further work is needed to assess the importance of coprophagous insects for ecosystem services.

Cattle as Dispersal Vectors of Invasive and Introduced Plants in a California Annual Grassland

Article

Full-text available

Jan 2016
RANGELAND ECOL MANAG

Plant invasions are a threat to rangelands in California. Understanding how seeds of invasive plants are dispersed is critical to developing sound management plans. Domestic livestock can transport seeds long distances by ingesting and passing seeds in dung (endozoochory), or by the attachment of seeds to skin and fur (epizoochory). Our objective was to characterize the role of cattle as seed dispersers of both invasive and non-invasive species via endo- and epizoochory in a Sierra foothills rangeland. To quantify endozoochory, we sampled dung from two dry-season grazing periods and evaluated seed content by growing dung for three months in a greenhouse. To quantify epizoochory, we collected seeds directly from the fur of 40 cattle. We categorized the invasion status and functional groups of all species found, and quantified landscape-scale vegetation composition in order to determine whether dispersal mode was associated with functional group, invasion status, or vegetation composition. Finally, we evaluated the potential for the noxious weed medusahead (Taeniatherum caput-medusae (L.) Nevski) to travel long distances on cattle fur using a detachment experiment with a model cow. We found that forms were more likely to be dispersed by endozoochory, and invasive species were more likely to be dispersed by epizoochory. Medusahead was dispersed exclusively by epizoochory, and was able to travel up to 160 m on a model cow. Our results suggest that cattle may be an important dispersal vector for both invasive and non-invasive plants.

The influence of feral horses dung piles on surrounding vegetation

Article

Full-text available

Mar 2014

The effect of grazing by large herbivores on grassland communities has been extensively studied, however less is known about changes associated with sites of high-intensity activity, such as dust bowls, tracks, urine patches and dung piles, that might induce disproportionate impacts to the directly affected areas and the surrounding vegetation. This paper explores the changes associated with exotic feral horse dung piles in relicts of natural grasslands in Argentine Pampas. We expected greater changes in the composition of plant communities and a greater facilitation effect on the establishment of invasive alien plants adjacent to the dung piles. Characteristics of the vegetation surrounding dung piles were recorded in 10025 cm plots located 0–1.5 m from the edge of the piles. We compared the immediate surroundings with reference plots at 5 m. The diversity of plant species increased as distance from the edge increased from 0–1.5 m; however, species richness was significantly higher in the first meter next to dung piles than 5 m away. Percentage cover of bare ground decreased further from the dung piles at both scales. Percentage cover of woody plants was greater at greater distances from the manure, whereas percentage cover of exotic plants was significantly higher next to the dung piles. The reported changes could be related to concentration gradients of nutrients liberated from the manure and/or to behaviour patterns of the horses, which may avoid grazing in the immediate surroundings of dung piles. These changes result in invasion windows facilitating the establishment and subsequent dispersal of exotic plant species in grasslands.

Relationships between Prosopis flexuosa (Fabaceae) and cattle in the Monte desert: Seeds, seedlings and saplings on cattle-use site classes

Article

Full-text available

Jun 2011

The fate of Prosopis flexuosa seeds dispersed by cattle is dependant on the spatial pattern of dung deposition and foraging movements. We hypothesised that cattle-use site classes explain the response variables related to seed input and fate of seeds, seedlings and saplings (small plants more than one year old). We defined sites with heavy cattle traffic ("trails" and "periphery of trails"), sites used for resting and foraging ("under Prosopis"), and sites where isolated individuals only walk ("under shrubs" and "bare soil"). Considering the established cattle-use site classes, our specific goals were to quantify and compare: (1) seeds transported in cattle dung; (2) seedlings 10 months after dung deposition; (3) established saplings; and (4) germinated and remaining seeds, and seedling survival in dung immediately after dung deposition. In a grazed field at Ñacuñán (Mendoza, Argentina) we worked in four similar areas, each consisting of 25-ha plots 2 km apart. Space use by cattle caused differential seed input: "under Prosopis" and in the "periphery of trails" animals deposited the largest amounts of dung and seeds. Ten months after dung deposition, the highest number of seedlings occurred on "trails", "under Prosopis" and in the "periphery of trails". In the long term, the highest number of established saplings occurred only in the "periphery of trails". The number of seeds germinated immediately after fruit production and dung deposition was very low. Survival of seedlings sprouting from dung-germinated seeds did not exceed one week. On "trails" and in the "periphery of trails" the persistence of seeds in dung was low because of dung disintegration by the action of cattle trampling. The seeds that did not remain in dung were probably the source of seeds that will germinate in the next wet season (i.e. 10 months after dung deposition). With different effects depending on cattle site activity and on the stage of the P. flexuosa plant (seed, seedling, or sapling), defecation and trampling appear to be important processes in the seed dispersal cycle. In this sense, cattle could benefit the establishment of P. flexuosa.

Déjections des herbivores domestiques au pâturage : caractéristiques et rôle dans le fonctionnement des prairies

Article

Full-text available

Mar 2012

Trois principaux facteurs conditionnent les caractéristiques physiques (taille des dépôts) et chimiques (teneur en eau, en nutriments…) des déjections des herbivores domestiques au pâturage : l’espèce, l’état physiologique de l’animal et la qualité de l’herbe ingérée, qui dépendra elle-même de la composition du tapis végétal et des conditions climatiques. À travers les déjections solides s’opère une restitution de matière organique et d’éléments nutritifs non assimilés vers le système sol-plante. L’importance énergétique de ce retour est telle que la dissémination des déjections est source d’hétérogénéité à l’échelle de la pâture. Cette hétérogénéité, elle même conditionnée par le comportement des animaux et les modalités de conduite, est à son tour source de diversité, tant floristique que faunistique. L’élimination de l’excrément de la surface du sol dépend des conditions climatiques et de l’activité de la faune saprocoprophage. L’activité de cette faune modifie à la fois les propriétés de la déjection et celles du sol (porosité, aération), ce qui favorise les activités microbiennes. A court terme, les déjections de grande taille ont un effet néfaste sur la végétation et entraînent un phénomène de refus de consommation de la part des bovins et des équins. A plus long terme, les déjections entraînent une augmentation de la croissance des plantes situées à proximité, effet qui peut persister jusqu’à deux ans. Si les transformations physicochimiques et les impacts des déjections sur la faune et la flore sont assez bien connus, en revanche nos connaissances sont lacunaires lorsqu’il s’agit de faire le lien entre le fonctionnement des communautés d’insectes coprophages et les fonctionnalités écosystémiques associées.

Species composition and functional structure of herbaceous vegetation in a tropical wetland system

Article

Full-text available

Oct 2012

Understanding driving factors of spatial heterogeneity in plant species composition and functional structure is a key step towards wetland ecosystems restoration and biodiversity conservation. We surveyed 60 randomly selected plots of 20 × 50 m each and collected 12 explanatory variables to understand potential impacts of natural environmental conditions, human disturbance and spatial position of plots variables on plant functional groups (PFGs) and species composition within grasslands of the Kilombero Valley Floodplain wetland, Tanzania. Ordination analyses were used to identify important vegetation gradients and establish significant natural environmental conditions, human disturbance and spatial position of plots correlates. Partial redundancy analysis (RDA) and partial canonical correspondence analysis (CCA) were used to determine the individual and shared effects of these three sets of explanatory variables on the PFGs and species composition, respectively. In total, 115 plant species, including 22 weed and 3 invasive species, and five PFGs were registered. Annual graminoid was the most abundant, whereas perennial forb the least abundant PFG with 50 and 1 % relative covers, respectively. Overall, spatial position, altitude, total organic carbon, cow dung, distance to the river and distance to kraal (cattle enclosure near human settlement commonly made of wood materials for animal protection) were important descriptors of both PFGs and overall species composition. Separate CCA of only weed and invasive plant species showed that some species, particularly the invasive Polygala paniculata were strongly associated with cow dung, indicating that present increase in cattle numbers may result in future problems associated with this species. Intensification of human activities and alteration of natural environmental conditions associated with these factors should be discouraged to maintain plant species composition and functional structure for wetland restoration and sustainable biodiversity conservation.

Plant dispersal syndromes are unreliable, especially for predicting zoochory and long‐distance dispersal

Article

Full-text available

Jun 2021

Plant dispersal syndromes are allocated based on diaspore morphology and used to predict the dominant mechanisms of dispersal. Many authors assume that only angiosperms with endozoochory, epizoochory or anemochory syndromes have a long‐distance dispersal (LDD) mechanism. Too much faith is often placed in classical syndromes to explain historical dispersal events and to predict future ones. What is usually recorded as the ‘endozoochory syndrome' is in reality a ‘frugivory syndrome' and this has often diverted attention from endozoochory by non‐frugivores (e.g. waterbirds and large herbivores) that disperse a broad range of angiosperms, for which they likely provide the maximum dispersal distances. Neither the endozoochory nor the epizoochory syndromes provide helpful predictions of which plants non‐frugivores disperse, or by which mechanism. We combined data from previous studies to show that only 4% of European plant species dispersed by ungulate endozoochory belong to the corresponding syndrome, compared to 36% for ungulate epizoochory and 8% for endozoochory by migratory ducks. In contrast, the proportions of these species that are assigned to an ‘unassisted syndrome' are 37, 31 and 28%, respectively. Since allocated syndromes do not adequately account for zoochory, empirical studies often fail to find the expected relationship between syndromes and LDD events such as those underlying the colonization of islands or latitudinal migration rates. We need full incorporation of existing zoochory data into dispersal databases, and more empirical research into the relationship between plant traits and the frequency and effectiveness of different dispersal mechanisms (paying attention to unexpected vectors). Acknowledging the broad role of non‐frugivores in facilitating LDD is crucial to improve predictions of the consequences of global change, such as how plant distributions respond to climate change, and how alien plants spread. Networks of dispersal interactions between these vertebrates and plants are a vital but understudied part of the Web of Life.

Prediction of permanent grasslands’ agroecological characteristics and compromises : focus on the Vosges Mountains

Thesis

Full-text available

Jul 2020

Geoffrey Mesbahi

In France, permanent grasslands are associated with agronomic and ecological characteristics: they provide half of overall forage, shelter vegetal and animal species, and store carbon. Increasing our understanding of agroecological characteristic determinants, and the trade-offs between characteristics, could help farmers and advisors to promote high-diversity grasslands, but also a diversity of grasslands. The objectives of this thesis are 1) to predict grassland characteristics using environmental, agricultural practices and vegetation criteria, 2) to predict grassland characteristics using vegetation classifications without information about environment and agricultural practices, 3) to study and predict trade-offs between characteristics at grassland scale, 4) to query knowledge transfer between researchers, farmers and farmer advisors. For this purpose, I built a database of almost 800 permanent grasslands from previous studies. I then selected a representative sample of 59 grasslands for this database over which I conducted field and lab analyses of botanical compositions, yields, forage qualities and soil properties. I also collected information about agricultural practices, climate and topography for each of these grasslands. My results show that botanical compositions are difficult to predict, and are mainly influenced by agricultural intensification, soil and elevation gradients. Prediction of agroecological characteristics show wide variabilities: some agronomical- and ecological- characteristics are predicted well by soil, climate, landscape and botanical composition criteria. However, using only vegetation classifications could not reliably predict ecological characteristics, despite the improvement of prediction quality when combining classifications. Study of trade-offs highlighted the impossibility to combine all the agroecological characteristics for one grassland. However, I observed combinations between yield and botanical diversity, between the different indices of nutritive value, and between patrimonial species and flexibility of management. Finally, several tools can be used to transfer knowledge between scientists, farmers and advisors, but an equilibrium between tools accuracy and ease to use have to be found. This thesis work brings new insights in our understanding of large scale permanent grassland agroecological characteristics and their trade-offs, thanks to the inclusion of many predictive criteria related to environment, agricultural practices and vegetation, but also thanks to the prediction of unknown characteristics. Finally, this thesis addresses the issue of developing polyvalent tools that can be used to predict grassland agroecological characteristics.

Prédiction de propriétés agroécologiques de prairies permanentes et de leurs compromis : l’exemple du massif vosgien

Thesis

Full-text available

Jul 2020

Geoffrey Mesbahi

Les prairies permanentes ont un intérêt majeur en France : elles assurent la moitié de la production fourragère, accueillent une riche biodiversité, et séquestrent le carbone. Mieux comprendre les déterminants des propriétés agroécologiques, mais aussi leurs compromis, peut aider les agriculteurs, leurs conseillers agricoles et les écologues à valoriser des prairies diversifiées, et une diversité de prairies. Les objectifs de cette thèse sont 1) d’identifier les critères du milieu, des pratiques agricoles et de la végétation qui prédisent les propriétés prairiales, 2) de prédire les propriétés agroécologiques à l’aide de typologies de prairies, sans connaissance précise des critères environnementaux ni des pratiques agricoles, 3) d’étudier et prédire les compromis entre propriétés d’une même prairie, 4) de se questionner sur la transmission des connaissances entre scientifiques, agriculteurs et conseillers. Pour atteindre ces objectifs, j’ai valorisé une base de données de près de 800 prairies permanentes d’études précédentes. J’en ai extrait 59 prairies représentatives du massif vosgien, sur lesquelles j’ai réalisé des relevés botaniques, des mesures de rendement, et des prélèvements de fourrage et de sol, et collecté des informations sur les pratiques agricoles, le climat et la topographie. Les résultats montrent que les compositions botaniques sont difficilement prédictibles et principalement influencées par des gradients d’intensité des pratiques, de sol et d’altitude. La prédiction des propriétés agroécologiques montre de grandes variabilités de qualité : des propriétés écologiques et agronomiques sont correctement prédites par des critères du sol, du climat, du paysage et de la composition botanique. Les propriétés écologiques sont difficilement prédictibles avec les typologies prairiales seules, mais la combinaison de typologies améliore la qualité des prédictions. Les résultats montrent aussi qu’une même prairie ne peut pas répondre à toutes les attentes des agriculteurs et conseillers, mais il est possible d’associer rendement et diversité botanique ; qualités nutritives ; ou encore espèces patrimoniales et souplesse d’exploitation. Enfin, la réflexion sur la transmission des connaissances entre scientifiques et acteurs de terrain montre qu’il est nécessaire de trouver un équilibre entre précision des outils et facilité d’utilisation afin de s’adapter aux attentes de tous. Cette thèse apporte donc de nouvelles connaissances sur la prédiction des propriétés agroécologiques des prairies permanentes et de leurs compromis à grande échelle, notamment grâce à la prise en compte de nombreux critères prédictifs liés aux milieux, aux pratiques agricoles et à la végétation, mais aussi grâce à la prédiction de propriétés encore méconnues. Enfin, cette thèse soulève le problème de la création d’outils polyvalents permettant de prédire les propriétés agroécologiques des prairies permanentes.

Grazing and Spatial Heterogeneity: Implications for Grassland Structure and Function

Book

Jan 2014

Grasslands cover around 30% of the Earth’s terrestrial surface and provide important ecosystem services. On the other hand, grasslands are among the most endangered ecosystems, threatened by land-use change, mainly through agricultural intensification or abandonment, and ongoing climatic changes, such as warming and drought. The principal aim of this book is to give an overview of current knowledge and future challenges for ecological studies on grasslands and to provide new perspectives for the management and conservation of grassland ecosystems. The first chapter presents some current threats to grasslands by reviewing the influence of land-use and climate change on the integrity of grassland ecosystems through changes in plant species composition and biodiversity (Chapter 1). While aboveground patterns and processes in grasslands are relatively well-known, the importance of belowground components in shaping grassland ecosystems is not well-understood. This is despite recognition that most of the grassland biomass and biodiversity is belowground, and that soil communities provide key ecosystem functions. Chapter 2 readdresses the importance of soil organisms by synthetizing their effects on grassland production and diversity, illustrated by a simplified soil food web with antagonist and mutualistic pathways. Soil microbial communities are particularly important for grassland functioning and need to be taken into account in management practices. As such, Chapter 3 highlights the importance of the seasonal variability of soil microbial communities and gives perspectives for bettering the management of disturbed grasslands. In addition to temporal variation, spatial variability should also be considered in grassland management. Chapter 4 presents a conceptual toolkit that accounts for spatial and temporal variability to facilitate restoration planning and management. Grazing is one of the most common practices in grassland management, with positive or negative effects on biodiversity and ecosystem functioning, depending on intensity and frequency. Chapter 5 investigates how grazing components (i.e. defoliation, trampling, animal excretions) affect spatial heterogeneity and as such, affect the functioning of grassland ecosystems and the services they provide. Grazing can be also used as a tool to restore degraded ecosystems and Chapter 6 shows how grazing, as well as other management practices, affect plant diversity and biomass production in a unique long-term restoration experiment in China. In a historic perspective, over the past two centuries, grasslands have been transformed globally by conversion to intense agricultural use, while extensively low-intensity grazed grasslands are disappearing. The ongoing effects of climate change are an additional threat to these endangered ecosystems as shown in Chapter 7. Climate change impacts are especially important in high elevation ecosystems, which are disproportionally affected, and Chapter 8 and 9 explore the influences of land-use and climate change on mountain and alpine grasslands. Both of these chapters focus explicitly on changes in plant functional group composition, which are key drivers of ecosystem properties and functioning. In this light, Chapter 10 gives an overview of the role of the largely understudied functional group of bryophytes by showing how this group contributes to the biodiversity of grasslands and constitutes a key group in the functioning of grassland ecosystems.

Patrones y procesos resultantes del efecto del pastoreo sobre la diversidad vegetal en el pastizal serrano del Sistema de Ventania

Thesis

Full-text available

Mar 2011

Alejandro Loydi

Grazing by large herbivores may promote changes in plant diversity according to their productivity and evolutionary history of grazing. In highly productive areas, plant diversity is expected to peak at moderate grazing intensities, and to show resilience in grasslands with long evolutionary history of grazing. Ventania System grasslands are highly productive and have apparently evolved with some grazing pressure by large native herbivores. Thus, it was expected that moderate grazing intensities promoted plants’ diversity, and that these grasslands were resilient to grazing. The objectives of this thesis were (1) to determine the relationship between grazing intensity and plant diversity, (2) to assess the diversity of the seedbank and the availability of safe sites for seedling emergence in exclosure and grazed areas, and (3) to describe grassland restoration after large herbivores removal. Classical vegetation census techniques were used, complemented by the experimental manipulation to characterize seedling emergence in safe sites. Moderate grazing intensities increased plant diversity, and grazing induced the replacement of palatable grasses by unpalatable grasses and forbs species. Grazing did not generate changes on the total seed density or species richness in the seedbank, but the seed density and richness of grass seeds was reduced by grazing. Competition was the most important factor limiting seedling emergence in exclosure areas, while litter shortage and soil compactation were the limiting factors in grazing areas. Herbivores removal caused a rapid increase in biomass, while reducing species richness. Three years after herbivores removal the botanical composition tended towards the supposed pristine botanical composition, showing a high level of resilience. These results were consistent with those expected, suggesting that Ventania system mountain grasslands are resilient to grazing by large herbivores, showing maximum plant diversity at moderate grazing intensity.

Do different livestock dwellings on single grassland share similar faecal microbial communities?

Article

Full-text available

Jun 2019
APPL MICROBIOL BIOT

Huge numbers of microorganisms reside in livestock faeces and constitute one of the most complex microbial ecosystems. Here, faecal microbial communities of three typical livestock in Xilingol steppe grassland, i.e. sheep, cattle, and horse, were investigated by Illumina MiSeq sequencing and quantitative real-time polymerase chain reaction (qPCR). Firmicutes and Bacteroidetes comprised the majority of bacterial communities in three livestock faeces. Sordariomycetes, Leotiomycetes, and Dothideomycetes were dominant in fungal communities, as well as Methanobacteria and Methanomicrobia were dominant in archaeal communities in three livestock faeces. Similar fungal community dominated in these samples, with 95.51% of the sequences falling into the overlap of three livestock faeces. In contrast, bacterial communities were quite variable among three different livestock faeces, but a similar community was observed in sheep and cattle faeces. Nearly all the archaea were identified as methanogens, whilst the most diverse and abundant methanogens were detected in cattle faeces. Potential pathogens including Bacteroides spp., Desulfovibrio spp., and Fusarium spp. were also detected in livestock faeces. Overall, this study provides the first detailed microbial comparison of typical livestock faeces dwelling on single grassland, and may be help guide management strategies for livestock grazing and grassland restoration.

Grazing-induced vegetation patchiness controls net N mineralization rate in a semi-natural grassland

Preprint

Full-text available

Feb 2011

Herbivores influence nutrient cycling either through direct effects (e.g. excreta) or through indirect effects such as a modification of plant-soil feedbacks. This work investigated if grazing-enhanced net N mineralization rates were related to (1) enhanced quality of plant litter and/or (2) reduced plant litter inputs. Rates of net N mineralization in soil and both the quantity and quality of litters were characterized in various plant patches occurring within a grazed grassland. Soil incubations were performed in controlled conditions to assess the respective role of litter quantity and quality on N mineralization. In laboratory incubations, the effect of litter quantity on net N mineralization rates was found to depend on litter quality. High inputs of litter produced by grazing-promoted species (C/N 11) stimulated net N mineralization rates, while high inputs of litter produced by grazing-reduced species (C/N 46) decreased rates of net N mineralization. The intensity of either the negative or positive effects of litter was then regulated by litter quantity. In the field, litter quality only varied within a limited range. Litter with the highest quality in the field (C/N 22) decreased N mineralization minimally compared to the lowest quality litter (C/N 46). Grazing-induced variations in litter quality monitored in the field thus appeared unlikely to cause measured variations in net N mineralization rates. Litter with C/N ratios of 46 and 22 stimulated N immobilization and reduction of their inputs increased the rate of N mineralization due to decreased microbial N immobilization. Within-grassland variations of litter quantity were large and negatively correlated with net N mineralization rates. Our results support the hypothesis that grazing-induced patchiness modifies net N mineralization rates by controlling microbial N immobilization mainly through changes in the quantity of litter-C supplied to the soil.

The impact of dung on inter- and intraspecific competition of temperate grassland seeds

Article

Apr 2017

Questions In temperate grasslands, seeds of numerous dry‐fruited plant species are dispersed via ingestion and subsequent defecation by grazing animals. Depending on the herbivore species and season, dung pats may contain a large assemblage of conspecific or heterospecific seeds competing for space, light and nutrients in the space‐limited environment of an individual dung pat. In an environment rich in nutrients, such as herbivore dung, the outcome of inter‐ and intraspecific competition might differ from situations where nutrients are limiting. Additionally, dung pats being small and spatially isolated habitats with very specific conditions may also impact competitive interactions. Besides the plant–soil interactions on competition known from literature, the specific quality and structure of dung pats might provoke more complex interactions between different seed densities and species combinations. Methods We conducted a greenhouse competition experiment using three common perennial grassland species. Agrostis stolonifera , Trifolium pratense and Trifolium repens were used in two‐species combinations with different proportions of each species and in monocultures. Seeds were sown in three seed densities (50, 150 and 250 seeds) and the effects of cattle and horse dung on establishment, growth and flowering were tested. Results Interactions, most probably attributable to interspecific competition, differed between species mixtures. Seeds sown in polycultures generally emerged sooner, but the resulting seedlings had lower relative growth rates compared with seeds sown in monocultures. Increased biomass was measured for each species when growing in polycultures while evidence for intraspecific competition was found in monocultures. T. pratense developed relatively more flowers when plants were growing in polycultures compared with monocultures. Few effects of seed densities were found, although higher seed densities led to lower establishment success in both monocultures and polycultures. Adding dung generally increased the time needed to emerge, relative growth rates and flowering, but decreased establishment success in monocultures. Conclusions Both seed density and the presence of dung shape the post‐dispersal fate of seeds. While high seed densities imply a cost due to lower germinability, the nutritive environment of dung acts as compensation, resulting in faster growth and an increased investment in reproductive tissues.

An attempt to restore a central European species-rich mountain grassland through grazing

Conference Paper

Full-text available

Dec 2003

This paper describes the effects of re-establishing seasonal cattle grazing by 0.7 animal.ha(-1) on vegetation in a long-term abandoned, and partly degraded, semi-natural mountain pasture in the Sumava National Park, Czech Republic. There was very uneven grazing intensity inside the locality, and grazing preference changed during the season: cattle grazed most of the time in productive but species-poor Deschampsia cespitosa swards, but changed to a species-rich Violion caninae stand in the middle of the summer. A species-rich Carex rostrata community was only grazed at the end of the season. Species-poor swards dominated by Nardus stricta and Carex brizoides were mainly used as resting areas. Both grazing and excluding from grazing had a negative effect on species diversity of the Deschampsia cespitosa swards. The soil seed bank contained only few species that are characteristic of mountain grassland communities, and seed dispersal of the target species by cattle dung was also found to be very limited. Thus both grazing and exclusion from grazing are probably of limited value for the restoration of species-rich grasslands from species-poor Deschampsia cespitosa swards in this case.

Fungal-mediated mortality explains the different effects of dung leachates on the germination response of grazing increaser and decreaser species

Article

Jan 2016
ACTA OECOL

Depending on their response to grazing, grassland species can be categorized as grazing increasers or decreasers. Grazing by livestock includes several different activities that can impact species differently. Recent evidence suggest that one of these actions, dung deposition, can reduce the germinative performance of decreaser species, thus favouring increasers. The present study tested the hypothesis that decreased germinative success of decreaser species is caused by a greater activity of fungal pathogens under the influence of dung leachates. We performed a phytotron experiment analysing the germination and fungal infections of fourteen species from Mediterranean grasslands. Species were grouped into phylogenetically-related pairs, composed of an increaser and a decreaser species. Seeds of each species were germinated under four different treatments (control, dung leachate addition, fungicide addition and dung leachate and fungicide addition), and the differences in germination percentage, germination speed and infection rate between each increaser species and its decreaser counterpart were analysed. Decreaser species were more affected by mortality than increaser ones, and these differences were higher under the presence of dung leachates. The differences in germinative performance after excluding the effect of seed mortality did not differ between treatments, showing that the main mechanism by which dung leachates favour increaser species is through increased mortality of the seeds of decreaser species. Drastic reductions in the number of dead seeds in the treatments including fungicide addition further revealed that fungal pathogens are responsible for these differences between species with different grazing response. The different vulnerabilities of increaser and decreaser species to the increased activity of fungal pathogens under the presence of dung leachates seems the main reason behind the differential effect of these leachates on species with different grazing response.

Impacts of cattle, fire and wind in rocky savannas, southeastern Brazil

Article

Jan 2008

The impacts of cattle (grazing, trampling and dung deposition), fire, and wind upon the rocky savannas (campo rupestre) of Minas Gerais, southeastern Brazil, are briefly evaluated. Peculiar life forms of vascular plants and their adaptations to natural disturbances are analyzed. The Intermediate Disturbance Hypothesis (IDH) is considered consistent with the findings for fire and wind. However, by altering the soil parameters, the presence of cattle brings about continuous and cyclic disturbances with long-lasting negative impacts on vegetation and on the survival of native species. The proportion of fire-adapted vascular plants species in campo rupestre was found to be comparable to those of the Brazilian zonal savannas on latossol (cerrado).

Seed predation and removal from faeces in a dry ecosystem. Basic and Applied Ecology, in press. http://dx.doi.org/10.1016/j.baae.2015.09.002

Article

Full-text available

Jan 2015
BASIC APPL ECOL

The fate of dispersed seeds from mammal faeces depends both on the animal that finds the seeds and environmental conditions. We explored the simultaneous influence of microhabitat and food availability on seed predation and removal from faeces by different animals in a protected Prosopis flexuosa open woodland site of the Central Monte Desert (Argentina). Using exclusion trials on simulated cattle faeces, we quantified seed predation in situ (within cages) and seed removal from faeces by rodents and ants in two different microhabitats (under shrub cover and on bare soil). This was done for two levels of availability of P. flexuosa fruits (during thefruiting season of P. flexuosa and when there are no fruits on the ground). We found that 67.9% of seeds remained in faeces, 28.9% were removed, and 3.2% were depredated in situ. Rodents removed more seeds under shrub cover than on bare soil, and during the non-fruiting period than during the fruiting period, whereas ants removed similar proportions of seeds in different microhabitats but almost exclusively during the fruiting season. This work acknowledges the complexity of dispersal processes and identifies the relative importance of some environmental factors for seed fate.

Seed predation and removal from faeces in a dry ecosystem

Article

Full-text available

Sep 2015
BASIC APPL ECOL

The fate of dispersed seeds from mammal faeces depends both on the animal that finds the seeds and environmental conditions. We explored the simultaneous influence of microhabitat and food availability on seed predation and removal from faeces by different animals in a protected Prosopis flexuosa open woodland site of the central Monte desert (Argentina). Using exclusion trials on simulated cattle faeces, we quantified seed predation in situ (within cages) and seed removal from faeces by rodents and ants in two different microhabitats (under shrub cover and on bare soil). This was done for two levels of availability of P. flexuosa fruits (during the fruiting season of P. flexuosa and when there are no fruits on the ground). We found that 67.9% of seeds remained in faeces, 28.9% were removed, and 3.2% were depredated in situ. Rodents removed more seeds under shrub cover than on bare soil, and during the non-fruiting period than during the fruiting period, whereas ants removed similar proportions of seeds in different microhabitats but almost exclusively during the fruiting season. This work acknowledges the complexity of dispersal processes and identifies the relative importance of some environmental factors for seed fate.

Plant diversity and composition associated with Himalayan musk deer latrine sites

Article

Full-text available

Sep 2015

Ungulate dung deposition may influence plant communities through seed dispersal or by animal disturbance and changes in soil nutrient levels on a small scale. The Himalayan musk deer Moschus chrysogaster uses common pellet defecation sites, often termed as "latrines". In the present study, we aim to assess the plant species composition, density, richness and diversity of seedlings, saplings and trees, shrubs, graminoids and forbs associated with musk deer latrines. We sampled vegetation at latrine sites, associated adjacent sites (5-10 m from the latrines) and control sites (30 m from the latrine sites within the same vegetation cover) in order to compare plant species composition, density, richness and diversity of the latrine sites with those of adjacent sites and control sites. The diversity of graminoid species was higher at latrine sites, indicating that musk deer may disperse certain grass species and that latrine sites may be important microhabitats for some grasses. Generally, plant species density, richness and diversity were lower at latrine sites, possibly due to trampling, browsing and changes in nutrients around the latrine sites. Plant species composition was not different between latrine sites and other forest sites. Human activities such as settlements, firewood collection and timber extraction, cattle grazing had a substantial effect on plant species composition, and, accordingly, these activities may adversely affect the musk deer habitat.

Spatial variation in plant species richness and diversity along human disturbance and environmental gradients in a tropical wetland

Article

Full-text available

Jun 2015

Human disturbance, natural environmental conditions and seed dispersal are often inferred as important drivers of plant community richness and diversity in wetland ecosystems. However, plant functional groups within a plant community have different environmental requirements and may respond differently to human disturbance. Therefore, the understanding of the relative importance of these variables in determining community and functional groups richness and diversity is important for improved management and wise use of wetland resources. We collected data on vegetation and environmental conditions, human disturbance and seed dispersal from 60 plots of 20 × 50 m, to identify variables that potentially affect total species richness and Shannon-Wiener diversity of the grassland plant community at the Kilombero Valley wetland, Tanzania. We further tested whether important predictor variables for species richness and Shannon-Wiener diversity differ among graminoid, forb and shrub functional groups. Overall, our results suggest that environmental conditions, human disturbance and seed dispersal determine spatial variation in species richness and Shannon-Wiener diversity of the grassland vegetation. The total richness and Shannon-Wiener diversity and the richness of shrubs decreased with distance from the Kilombero River, whereas the total Shannon-Wiener diversity and the Shannon-Wiener diversity of graminoids decreased with the increase in grazing intensity. Shrub species richness was related to the spatial position of plots and decreased with total organic carbon of soil. Current increase in human disturbances through cattle husbandry and changes in natural environmental conditions (e.g. through water diversion and drainage) should be discouraged in order to restore and sustain biodiversity of the Kilombero wetland.

HETEROGENEITY OF THE VEGETATION AND OF THE GRAZING : FUNCTIONAL CONSEQUENCES IN NATURAL GRASSLAND

Thesis

Full-text available

Dec 2006

Nicolas Rossignol

Grazing influence the primary productivity and the quality of the vegetation and can influence the fluxes of elements and the biogeochemical cycles. The consequences of this interaction between herbivores, plants and soil on the functioning of the ecosystems could vary because the impact of grazing on the functions of the vegetation is depending on the plant communities and the grazing intensity. The objective of this thesis is to analyze the impact of a grazing intensity gradient on the functioning of a humid grassland. The biological model of this study is a grassland of the Marais Poitevin (France) which is grazed since the 10th century. Three plant communities occur in this grassland and the spatial variations of grazing intensity led to the creation of a patchwork of plant patches within each plant community. Within each plant community, the grazing intensity gradient led to a spatial heterogeneity of the functional processes of the grassland linked to the heterogeneity of the vegetation. Along the grazing gradient, primary productivity decreases while the quality of the vegetation increases and the net N mineralisation rate increases. Within each plant community, the range of the nitrogen cycle variations appears to be linked to the range of the variations of the vegetation functions. The impact of grazing on the vegetation functions was driven by two main mechanisms. The long-term effect of grazing influences the floristic composition of the plant communities and thus influences the vegetation functions. The grazing gradient led to a wide modification of the floristic composition of the plant communities. The effect of this grazing gradient on the vegetation functions was more important when the dominant plant functional types in ungrazed conditions, perennial monocots, was replaced by annual monocots and dicots. In grazed situation, the functions of the vegetation were influenced by the plants' responses to the defoliation. Defoliation stimulated the growth rate of the vegetation. The intensity of this stimulation was strongest with the low frequency of defoliation and allowed a compensatory growth which differ amongst the patches. This response was characteristic of each plant patch. The interaction between defoliation frequency and floristic composition led, along the grazing gradient, to a more important decrease of primary productivity within the meso-hygrophilous plant community than within the mesophilous one. The impact of the grazing gradient on the functions of the vegetation drives the quantity and the quality of the inputs of organic matter through the soil and leads to an effect on the net N mineralisation rate. The quantity of carbon inputs appeared to control the soil microbial growth and to stimulate the nitrogen microbial immobilisation which led to a decrease of the mineral nitrogen pool available for the plants. Consequently, the reduction of plant litter inputs along the grazing gradient led to a stimulation of the net N mineralisation rate. The stability or the change of the functions of the vegetation, in terms of primary productivity and vegetation quality, along the grazing gradient appears to drive the impact of grazing on the biogeochemical cycles.

Invasion of the cosmopolitan species Echinochloa colona into herbaceous vegetation of a tropical wetland system

Article

Full-text available

Sep 2014

The negative effects of alien plant species on ecosystem structure and functions are increasingly recognised, and efforts to control these species are vital to restore degraded ecosystems and preserve biodiversity. However, we lack a full understanding of factors that determine alien species invasions along spatial gradients in herbaceous vegetation of tropical systems. We therefore examined the effects of community properties, environmental variables and human-related disturbance factors on the invasion of the alien grass Echinochloa colona (L.) Link at small- and large scales in the Kilombero Valley wetland, Tanzania. Generalized additive mixed models showed that E. colona abundance on a small scale was negatively related to above-ground biomass and evenness of resident species, whereas E. colona abundance was positively related to grazing intensity. On a large scale, biomass (negatively related to E. colona abundance) and distance to river (positive) were important in explaining E. colona abundance. These findings support the assertion that different factors may contribute to the invasion of alien plant species at different spatial scales, as also reported in many temperate systems. Overall, our results show that successful invasion of alien species is a function of plant community properties, human-related disturbance and favourable environmental conditions. Effective management strategies should consider mitigations that can increase the biomass and evenness of native species and a reduction of grazing pressure to restore the wetland and conserve biodiversity.

Structure and dynamics of alvar vegetation on Öland and some related dry grasslands: Introduction

Article

Full-text available

Jan 2007

Eddy Van der Maarel

Fraß- und Raumnutzungseffekte bei Rinderbeweidung in halboffenen Weidelandschaften: Leitbildflächen und Restitutionsgebiete im Emsland (Niedersachsen). [Habitat utilisation and impact of cattle grazing in semi-open pasture landscapes in target and restitution areas in the Emsland region (Lower Saxony).]

Article

Full-text available

Jan 2004

In the Emsland region the impact of cattle grazing on the vegetation of semi-open pasture landscapes was studied by exclosure experiments and a raster-based analysis (50-m spacing) of grazing pressure. The exclosure experiment refers to inland sand dune complexes, whereas the raster-based analysis comprises the whole vegetation mosaic of the open pasture landscape (grazed sand dunes, fresh and moist pasture habitats). Both approaches were undertaken in target and newly restored areas. For the exclosure experiment a set of grazed plots was fenced and the cattle excluded in the target area in the year 2000. There were only slight changes in the fl oristic composition of the studied sand vegetation (Spergulo-Corynephoretum and Diantho-Armerietum) in the 4-year period. Especially the moss Ceratodon purpureus and the grass Festuca fi liformis show higher population dynamics in the grazed plots. We expect this “lag period” to be followed by stronger effects of fl oristic change in the coming years. According to the results of the raster-based analysis (which used phytosociological relevés carried out yearly and a special grazing-pressure evaluation: three times a year) cattle generally prefer plant species of moist to fresh or not too dry grasslands in the studied Vegetation mosaic (e.g. species of Lolio-Cynosuretum, but also of Diantho-Armerietum and Agrostis capillaris-community). Preferred species were: Agrostis capillaris, A. stolonifera, Alopecurus geniculatus, A. pratensis, Bidens frondosa, Cerastium arvense, Dactylis glomerata, Elymus repens, Holcus lanatus, Juncus effusus, Poa pratensis and Rorippa palustris. Target species of the Spergulo-Corynephoretum are not preferred but the open dune structures had a function as “wellness” places (wind infl uence causes lower densities of Diptera). This basal preference list is modified mainly by three aspects: 1. stocking density, 2. ratio between moist, fresh and dry grassland in the vegetation mosaic, 3. specific weather conditions during a given year. Although all investigation areas were extensively grazed by cattle, there were differences in the stocking densities (counted for May to October): target area with 0.7-0.8 livestock units/ha, restoration areas “Hammer Schleife” with 0.6 livestock units/ha and “Wester Schleife” with 0.9 livestock units/ha. In the case of the target area all vegetation types were grazed, including the sand dune complexes. In the case of the restoration areas (which currently have more fresh and moist grassland than the target area) the sand ecosystems were sufficiently grazed in the “Wester Schleife”, with 0.9 livestock units/ha, but not in the area “Hammer Schleife”. Therefore in the case of dominance of fresh/moist grassland the stocking density should be increased to 0.9 in the area “Hammer Schleife”. In future it is expected that both restoration areas may change their vegetation mosaic more and more by accumulation of fluviatile sand (as already happened in winter 2002/03); the stocking density has then to be adapted to the value of the target area. The faeces are more or less homogeneously distributed in the area and do not correlate with the sites of high grazing pressure, which guarantees the dispersal of endozoochorous species throughout vegetation mosaic.

NUTRIENT DYNAMICS IN BAHIAGRASS SWARDS IMPACTED BY CATTLE EXCRETA

Article

U.R. White

Grazing and spatial heterogeneity: Implications for grassland structure and function

Chapter

Jun 2014

Grazed grasslands are dynamic, complex ecosystems characterised by patchy resource inputs and vegetation structure under constant modification by the management of domestic herbivores. Over the last decade there has been increasing recognition that plant and soil spatial heterogeneity has the potential for significant effects on biotic interactions, diversity and ecosystem properties. Nevertheless we know little about the overall trends of response to grazing-induced heterogeneity in grasslands systems. After an overview of how grazing animals promote spatial heterogeneity in grasslands, we synthesize literature to answer the question: does fine-scale grazing-induced spatial heterogeneity significantly affect field-scale grassland structure and function? We examine how spatial patterns of grazing components (defoliation, trampling and animal returns) mediate changes in plant community composition and field-scale diversity via spatial coexistence mechanisms. We then consider how these grazing components modify ecosystem function, reviewing the impacts of heterogeneity in defoliation and soil nutrients on above- and below-ground ecosystem processes. Overall, grazing-induced spatial heterogeneity appears to enhance plant and arthropod diversity in grasslands. The relatively few studies published on effects of spatial heterogeneity and grazed grassland function provide clear patterns of nitrogen losses in relation to urine inputs, but highlight the need for work on other aspects of grassland function. The importance of plant-soil feedbacks and effects of grazing-induced heterogeneity on plant functional traits, and ultimately on ecosystem properties, are discussed. We highlight gaps in current understanding and suggest that the study of spatial heterogeneity in managed grasslands is critical for accurate prediction of field-scale processes and their cascading effects on ecosystem service provision.

Long term defoliation by cattle grazing with and without trampling differently affects soil penetration resistance and plant species composition in Agrostis capillaris grassland

Article

Dec 2014
AGR ECOSYST ENVIRON

There are no long-term experimental studies dealing with plant community responses to trampling. Here we report the results for soil penetration resistance and plant species changes in mesotrophic temperate Central European grassland after 12-years of grazing management with and without trampling by cattle. Five grazing treatments (intensive and extensive grazing; cut for hay in June followed by intensive or extensive grazing; and intensive grazing with no trampling under permanent electric fencing) with two replicate blocks have been applied since 1998. Species richness, species composition, sward height, nutrient availability in soil and soil penetration resistance were recorded and evaluated. For statistical analysis we used one way ANOVA and RDA with the Monte Carlo test. Long term grazing by large herbivores had a significant effect on soil penetration resistance with the lowest values in the ‘not trampled’ treatment. Legumes, particularly Trifolium repens, and short forbs (especially Veronica serpyllifolia) were supported by intensively defoliated and trampled treatments, whereas tall forbs (mainly Aegopodium podagraria, Hypericum maculatum) prevailed under the extensively managed treatments. The cover of tall and short graminoids was not dependent on applied treatments. The ‘not trampled’ treatment had the highest prevalence of bryophytes (domination of Rhytidiadelphus squarrosus) and was also the richest in a number of vascular plant species; however, it also had the lowest evenness index. Long-term defoliation by grazing animals without trampling does not lead to the creation of typical pasture swards. Species forming pasture communities are essentially dependent on regular defoliation by grazing and regular trampling by hooves, which causes a high degree of soil compaction as well as sward disruption.

Soil surface N balances and soil N content in a clay-loam soil under Irish dairy production systems

Article

Full-text available

May 2013

This study evaluated the effect of a dairy system involving grazing over the winter on a soil surface N balance (SSB) and soluble N content in a clay loam soil in comparison with early spring calving systems. The SSBs were calculated for each paddock within three dairy systems for 2 years. Inputs included N entering the soil in fertilizer, slurry, excreta, atmospheric deposition and biological N fixation. Outputs consisted of N leaving the soil in harvested and grazed herbage. Nitrogen surplus was calculated as a difference between N inputs and outputs. Soluble N was assessed in soil extracts at three depths to 0.9 m. The management of the systems resulted in N surplus from 113 to 161 kg N ha−1 year−1 and N use efficiency of the soil component from 63 to 72 % without significant variation between the systems. The dairy system had no effect on soil N content as its variation was likely buffered by inherent soil properties (heavy texture, high C, pH) and the presence of shallow groundwater. The biochemical anaerobic reduction processes (i.e. denitrification) likely ensured soil oxidised N consistently low (<20 kg ha−1). Consequently, the system involving grazing over the winter on these soils did not create an additional environmental pressure via N losses to groundwater and N2O emissions compared with early spring calving systems. The size of soil inorganic N pools was mainly controlled by the hydrological factors and soil temperature, which are the most important factors controlling microbial activity, biochemical processes and leaching.

Endozoochorous Seed Dispersal by Yak and Tibetan Sheep on Alpine Meadow and Shrubland

Article

Full-text available

Mar 2023
RANGELAND ECOL MANAG

Diversity and structural changes in Cerrado Rupestre under effects of disturbances

Article

Jan 2021
Rev Bras Botânica

Vegetation formations are undergoing constant floristic and structural change over time and space. Assessing these changes represents an important step to understand the effects of disturbances and propose ecosystem conservation and management strategies. We still lack, however, information on the dynamics of the woody vegetation in Cerrado Rupestre (rupestrian Cerrado—RC) formations over time, which comprise important refuge of the vegetation of the Brazilian Savanna and occur on rocky outcrops, which are considered restrictive environments. In this context, we describe the changes in floristic composition, richness, species diversity and structure of vegetation in RC over 12-year and link patterns to the disturbances that occur in the area—wildfire and cattle presence. We gathered data from three surveys conducted in RC in the Pireneus State Park (PSP), Goiás, Brazil. We also registered hot pixels inside the study area and in the PSP neighboring area indicating presence of bovine and equine cattle in the Park. Disturbances, occurrence of wildfires, and presence of cattle promoted changes in vegetation structure, with a decrease in the number of small individuals, but not in diversity parameters. The increase in richness, evenness and diversity, even under the effect of disturbances, demonstrates the resilience of the RC. However, if these disturbances keep occurring, resilience will be compromised, with clearer changes in floristic composition and vegetation structure, according to what we proposed in a theoretical model describing the synergistic influence of cattle presence, exotic grass and wildfires on the dynamics of the Cerrado Rupestre.

SPECIES-RICH SWARDS OF THE ALPS: Constraints and opportunities for dairy production

Chapter

Jan 2006

A five‐year rotational grazing changes the botanical composition of sub‐alpine and alpine grasslands

Article

Full-text available

Jun 2018

Aim The implementation of Grazing Management Plans (GMP), a specific policy and management tool, aimed at enhancing farm productivity, while preserving plant diversity, soil, and landscape. The GMP are based on rotational grazing systems (RGS) with animal stocking rate adjusted to keep it balanced with grassland carrying capacity. The aim was to test the five‐year effects produced by GMP implementation on botanical composition, plant diversity, and soil nutrient content on sub‐alpine and alpine pastures. Location Val Troncea Natural Park, western Italian Alps. Methods A total of 199 vegetation transects was carried out in summer 2011 and repeated in summer 2016. The botanical composition was recorded and plant diversity indexes, i.e. species richness and Shannon diversity (H’ index) were computed. Moreover, the mean soil nutrient content was indirectly estimated through the computation of Landolt N indicator value (N index) for each transect. Pair‐sample statistical tests and PERMANOVA were perfomed at different levels: on the whole vegetation dataset, on vegetation communities (i.e. vegetation types and ecological groups), and considering functional pools of species. Results Considering the whole vegetation dataset, species richness, H’ index, and N index significantly increased from 2011 to 2016. Moreover, species richness significantly increased in almost all the vegetation ecological groups, with the highest increase within mesotrophic one. The H’ index significantly increased in eutrophic, pre‐forest, and thermic groups, while N index increased in all the vegetation groups, except in the eutrophic and snow‐bed ones. A significant difference in botanic composition was detected within oligotrophic, mesotrophic, and thermic groups. The number and cover of nitrogen‐poor high‐elevation species increased in all groups and this result could be probably related to the effects produced by livestock, which promoted seed transportation and increased connectivity amongst different communities. The meso‐eutrophic species number and cover significantly increased within thermic, mesotrophic, and pre‐forest groups, suggesting a greater use of such areas by livestock under RGS than continuous grazing system. Conclusions The implementation of a RGS with stocking rate adjustments proved to be an effective and a sustainable management tool to enhance botanical composition and plant diversity of sub‐alpine and alpine grasslands over a five‐year span. This article is protected by copyright. All rights reserved.

Can goats disperse seeds of herbaceous pasture plants in Mediterranean grasslands?

Article

Oct 2016
SMALL RUMINANT RES

In the Mediterranean region, endozoochorous seed dispersal is a potential alternative for the recovery of degraded or abandoned grasslands and shrublands. The objectives of this study were to quantify the number of seeds that pass through the goat gut and to determine whether this process affects seed germination in six common herbaceous species of the Mediterranean area (Ornithopus compressus L., Biserrula pelecinus L., Medicago polymorpha L., Melilotus officinalis L. Pall, Festuca ovina L. and Dactylis glomerata L). We also examined whether the inclusion of the seeds in dung affected seed germination and seedling establishment and growth. The highest seed recovery rate was obtained 24–72 h after ingestion. The amount of retrieved seeds varied among species and was generally low, with significant differences among some leguminous and grass species. With the exception of M. officinalis, the quantity of retrieved legume seeds (1.5–6.8%) was greater than that of the grass seeds (0.9–1.1%). A significant relationship was found between recovery of the seeds and their hardness and volume. In all species, the recovered seeds presented significantly lower germinability than seeds that had not been consumed. In general, all recovered legume seeds showed higher average germination rate values (18–50%) compared to recovered grass seeds (0–14%). Seedling emergence was lower in intact than in crumbled dung pellets and, in most cases, the values of both of these were lower than that of unconsumed (control) seeds. No seedling emergence was recorded for seeds of B. pelecinus and O. compressus contained in intact or crumbled faeces at all sampling times. While the percentages of recovery and subsequent emergence found in this study are low in absolute terms, we can conclude that a significant number of seeds may become established from the dung and could be a potential alternative for the recovery of degraded or abandoned grazing areas.

Der Federsee: Landschaft und Dynamik im Neolithikum

Chapter

Full-text available

Jan 2010

This paper gives an overview over late neolithic landscape and settlement dynamics in the Federsee Region in Upper Swabia. It relies on botanical, dendrotypological and archaeological data.

Seedling dynamics in an environmental gradient of Andean Patagonia, Argentina

Article

Jan 2013

In this chapter, we analyze the most important environmental and biotic factors that influence seedling dynamics of three of the most conspicuous species grown in a foreststeppe gradient of Patagonia in Argentina. In a short distance of about 80 km in this gradient, vegetation abruptly changes from pure Nothofagus pumilio forests (grown from the timberline down to altitudes of about 1,200 m a.s.l., with 2,000 to 3,000 mm yr-1 of precipitation), to mixed Austrocedrus chilensis-Nothofagus dombeyi forests and pure A. chilensis forests towards the east, and isolated A. chilensis forests in the ecotone with the steppe (at altitudes from 900 to 500 m a.s.l. and 1,200 to 500 mm yr-1 of precipitation). Vegettion then changes to a grassland steppe zone, located at about 400 to 600 m a.s.l., and in which precipitation barely reaches 300 to 400 mm yr-1. Although precipitation values greatly differ, all areas share the same Mediterranean climate, with rains concentrated during late fall and winter followed by a marked dry period during spring and summer. The most important native species in this gradient are the trees, Nothofagus pumilio (lenga), in the higher slopes of the Andes, Austrocedrus chilensis (cypress or ciprés de la cordillera) at the mid slope and in the forest-steppe ecotone, and the grass Festuca pallecens (coirón blanco), in the steppe zone. All three species reproduce by seed, and form transient soil seed banks. In the case of Festuca pallescens this bank is annually replenished, while for A. chilensis and N. pumilio seed production occurs during favorable periods that may vary from two to several years. Among the environmental factors that affect seedling dynamics, water stress during the summer dry period appears to be of paramount importance for Festuca and A. chilensis seedlings, and less important for N. pumilio. For the latter species, and after germination, light availability appears to be crucial for further sapling growth. Right after germination, young Festuca or A. chilensis seedlings appear to grow better under protected microsites provided by either an adult Festuca plant or a nurse shrub in the case of A. chilensis. This facilitation effect seems to change as seedlings become older, shifting this interaction to competition as secondary succession progresses. Apart from the environmental conditions, seedling dynamics of all three species are also affected by natural (fires, earthquakes, avalanches, falling out of senescent trees in the case of N. pumilio) and anthropogenic disturbances (fire, grazing, browsing, and logging). Although the inferences made here about seedling dynamics may be valid for the whole area of distribution of A. chilensis and F. pallescens, for N. pumilio, by instance, will be constrained to continental Patagonia (excluding Tierra del Fuego), in which Mediterranean climatic conditions prevail.

Coprophilous communities : a way to understand the relationship between structure and functioning face to disturbances

Thesis

Full-text available

Dec 2014

Thomas Tixier

Les assemblages d'espèces colonisatrices des déjections constituent des systèmes d'étude intéressants de par la nature de la ressource exploitée et de par le rôle qu'ils exercent dans les écosystèmes pâturés. Une grande diversité d'espèces d'insectes, principalement des diptères et des coléoptères, colonisent les bouses et contribuent à leur disparition, permettant un apport en nutriments au pâturage. Comprendre le lien entre ces différentes espèces et les fonctions écologiques réalisées représente donc un enjeu afin de préserver ce système et d'en assurer son bon fonctionnement. Certaines molécules administrées comme endectocides au bétail, comme l'ivermectine, impactent la structure de la communauté coprophile par leurs effets toxiques sur certains groupes comme les Sepsidae. Bien que leurs effets se soient montrés significatifs sur l'émergence des insectes coprophiles, la disparition des bouses ne s'en est pas trouvée affectée. Il convient alors de rester prudent sur les effets à long terme de ce type de molécules, même si à court terme les effets ne paraissent pas pertinents. La première semaine est essentielle à la bonne dégradation des bouses par l'action d'une première vague de colonisation par les insectes coprophages, tandis qu'en seconde semaine la colonisation par les prédateurs en réduit la vitesse. L'ensemble de la communauté coprophile ne permet donc pas d'accélérer le processus de recyclage des bouses. Une augmentation des effectifs de bousiers accélère la disparition des bouses et indirectement favorise la minéralisation de la litière dans le sol. Toutes les espèces ne contribuent pas équitablement au fonctionnement du système. Les plus gros fouisseurs enterrent des quantités plus importantes de matière fécale, facilitant ainsi les échanges de nutriments entre le sol et la déjection. D'importantes pistes restent à développer concernant les facteurs influençant la colonisation et les interactions entre les organismes afin de pouvoir utiliser les bousiers comme bioindicateurs pour en mesurer les services rendus.

The role of past and present management in the seed dispersal of grassland plants in the rural landscape

Article

Jan 2010

Alistair G Auffret

Cattle Dung as Vector of Spreading Seeds of Exotic Species in the Flooding Pampa Grasslands (Buenos Aires, Argentina)

Article

Mar 2010

Emergence of seedlings from cattle dung collected in different seasons from grasslands of the Flooding Pampa was analysed. The objective of this work was to find out (1) how high the proportion of seeds from exotic species in the seeds spread by cattle dung is, and (2) what the forage quality of the species spread through cattle dung is. Fresh dung was collected in late spring and late summer from three grasslands. Seedling emergence from dung was done in greenhouse conditions. Seedling number, forage quality and origin of the species were determined. We found 121 plant species growing in the grasslands. The number of species emerging from dung was 41. Twenty-four and 36 species emerged from dung collected in late spring and late summer, respectively. Nineteen species were common for both seasons. There were 5.33 ± 0.26 and 1.00 ± 0.15 (mean ± SE) native and exotic species, respectively, per dung sample (22.50 g dry weight) collected in late spring. From the dung collected in late summer emerged 7.70 ± 0.31 and 2.63 ± 0.18 native and exotic species per sample, respectively. Carex spp., Cyperus spp. and Juncus spp. (native species) were the most abundant (95%) in dung collected in late spring. In dung collected in late summer Cynodon dactylon (an exotic species) represented 76% and Carex spp., Cyperus spp. and Juncus spp. represented 9%. The most abundant species emerged from dung were of low forage quality and thus are considered weeds in crop fields. Seed propagation through cattle dung helps to explain the increment of exotic species in the Flooding Pampa grasslands under grazing. The results are relevant for the range managers who normally move the cows between stubble crop fields and grasslands, spreading through dung seeds of species of different origin and quality.

Stroh PA, Mountford JO, Hughes FM. The potential for endozoochorous dispersal of temperate fen plant species by free roaming horses. Applied Vegetation Science

Article

Aug 2012

QuestionsCan free‐roaming Konik horses digest and subsequently disperse seeds of plant species growing in a temperate fen environment? Which species have the potential to be dispersed internally (endozoochory), and do they share common plant and seed traits? How could potential dispersal via endozoochory impact upon grazing management and the natural recolonization of wetland vegetation at a landscape scale? LocationWicken Fen NNR, Cambridge, UK. Methods Twelve dung samples were collected for one calendar year (Jun 2009–May 2010) from a free‐roaming herd of Konik horses grazing vegetation at Wicken Fen NNR. Germinable seed content of the dung was determined by means of a seedling emergence study. Species presence and estimated cover/abundance were recorded for the grazed (background) vegetation in spring and summer 2009. ResultsAlmost one‐third of all species present in the background vegetation were also identified in the dung samples. There was an equal split between graminoids and forbs, but substantially more graminoid germinable seeds. Species were dispersed year‐round, with the number of species peaking in Sep and again in Dec. Of the 13 traits measured, there were significant differences between dung and background vegetation for six traits. Mean values for seed release heights (minimum and maximum) and dispersule weight were significantly lower in species found in the dung, whilst dung species had significantly greater numbers of seeds per shoot, inferred Ellenberg nitrogen values and seed bank persistence. Conclusion Year‐round free‐roaming grazing has the potential to make a considerable contribution to the long‐range dispersal of species growing in temperate fen habitats, and is likely to complement alternative dispersal strategies. However, germination and establishment of species post‐dispersal fate will be governed by a wide range of environmental conditions.

Species composition and plant biomass of an ungrazed and a grazed grassland at Ujjain, india

Article

Full-text available

Apr 1987

J. C. Dagar

Grazing lands

Preliminary classification and ecology of dry grassland on Ölands Stora Alvar (Sweden)

Article

Full-text available

Dec 1986
NORD J BOT

Four plant community types are described for Öland's Stora Alvar, the limestone plateau of South Öland and preliminary classified syntaxonomically: (1) Crepis pumila – Allium alvarense ass. (2) Helianthemum oelandicum – Galium oelandicum ass. (3) Gypsophila fastigiata – Globularia vulgaris ass. and (4) Veronica spicata – Avenula pratensis ass. (with two subassociations, the Sedum reflexum and Galium boreale subass.). The ecology of these types is discussed with emphasis on soil depth, frost perturbation and the combined effects of summer drought and grazing intensity. Various endemic taxa appear to be good character species for the community types described. The typical local ecology of some common species is discussed with the suggestion that they might have formed endemic ecotypes which should be further investigated. The communities described are very rich in cryptogams. The floristic variation as expressed by the cryptogamic species composition shows largely the same pattern as that shown by the phanerogams.

Transformation of Cover-Abundance Values in Phytosociology and its Effects on Community Similarity

Article

Full-text available

May 1979

Eddy Van der Maarel

The numerical treatment of phytosociological data is often based on estimates of cover and/or abundance according to the Braun-Blanquet and Domin scales. Since Schwickerath (1931, 1938, 1940) and Tüxen & Ellenberg (1937) published their transformations there has been discussion on the way the scale values should be used in calculations Qualitative approaches, i.e. based on presence and absence have also been favoured (e.g. Williams & Lambert 1959, van der Maarel 1966) Dagnelie (I960) proposed a pseudoqualitative basis for various calculations by means of a ‘coupure’. A coupure includes the deletion of lower values, usually according to a fixed criterion, e.g. the number of occurrences in a phytosociological table to be remained should be as close as possible to 50%. Dagnelie’s approach remained largely unknown and apparently it has never been tested.

Effects of three seasons of experimental trampling on five montane forest communities and a grassland in Western Montana, USA

Article

Full-text available

Dec 1987
BIOL CONSERV

David N. Cole

Six vegetation types, one grassland and five forest communities, were experimentally trampled for three successive summers. The relationships between amount of trampling and vegetation cover loss, species loss, and increase in penetration resistance were strongly curvilinear, approximating an asymptotic model in most cases. The relationship between amount of trampling and increase in mineral soil exposure was linear, beyond the level of trampling required to expose mineral soil. The relative vulnerability of each vegetation type was assessed, as was the number of years of trampling required before damage levelled off. Implications for management of recreation sites and design of trampling experiments are discussed.

Grazing as a management tool in the restoration of species-rich grasslands

Article

Jan 1987

J.P. Bakker

Species composition and plant biomass of an ungrazed and a grazed grassland at Ujjain, India.

Article

Jan 1987

J. C. Dagar

Dung decomposition and its effects on the soil component of a tropical grassland ecosystem

Article

Jan 1984

C.P.E. Omaliko

(1988). Comparative Plant Ecology. A Functional Approach to Common British Species.

Article

Apr 1989

Dung Deposition, Breakdown and Grazing Behavior of Beef Cattle at Two Seasons in a Tropical Grassland Ecosystem

Article

Sep 1981

C. P. E. Omaliko

The effects of seasons on size, number and area of the dung deposited on a grazed paddock were examined. Rate of dung breakdown, herbage fouling, and rejection were also investigated. Significant seasonal differences were found in number, size, area of dung and in proportion of paddock fouled per grazing such that these values were higher in wet than in dry season. A higher breakdown rate was obtained in the dry season when the termites were the main degradation agents than in the wet season when the dung was degraded mainly by the copriphilous fungi. The herd rejected the fouled herbage for a longer period during wet season than during the dry season. Two breakdown patterns for the dry season (depending on the presence of termites in the ecosystem) were suggested. Herbage rejection was discussed in relation to animal production and range improvement.

Seasonal Variation in the Seed Banks of Herbaceous Species in Ten Contrasting Habitats

Article

Nov 1979

(1) Measurements have been made of seasonal variation in the density and composition of the reservoir of germinable seeds present in surface (0-3 cm) soil samples collected at 6-weekly intervals from ten ecologically-contrasted sites in the Sheffield region. (2) The procedure was not designed to provide a complete assessment of the seed flora, and the methods were found to be ineffective in recovering germinable seeds of those species (e.g. Endymion non-scriptus, Viola riviniana, several Umbelliferae) in which there is only a brief interval between fulfilment of a chilling requirement and the onset of germination. (3) The techniques adopted were particularly suitable for the detection of persistent seed banks (i.e. those in which some of the component seeds are at least 1 year old), and also allowed recognition of species in which there is a transient accumulation of detached germinable seeds during the summer. (4) Comparison of the results obtained for populations of the same species in different types of habitat suggests that seasonal variation in seed number is a function of the species rather than of the environment. (5) It is concluded that the major evolutionary force determining the nature of the seed bank is the selective advantage derived from mechanisms of seed dormancy and germination which allow seedlings to evade the potentially-dominating effects of established plants. (6) From the data collected in this study, four types of seed bank (Types I-IV) have been recognized, and an attempt has been made to assess their ecological significance. (7) The transient seed banks (Types I and II) are adapted to exploit the gaps created by seasonally-predictable damage and mortality in the vegetation, whilst the persistent seed bank (Type IV) confers the potential for regeneration in circumstances where disturbance of the established vegetation is temporally and/or spatially unpredictable. A second type of persistent seed bank (Type III) has characteristics intermediate between those of Types I and IV, and contains some seeds which germinate soon after release and others which are more persistent in the soil. (8) A feature of the results was the lack of a general correspondence between the species-composition of the seed flora and that of the associated vegetation. At certain sites, substantial persistent seed banks were detected for species which were either extremely scarce or did not occur at all in the established vegetation. (9) Both transient and persistent types of seed banks were represented at each of the ten sites; this is consistent with the hypothesis that complementary mechanisms of regeneration are involved in the maintenance of floristic diversity.

Studies in the Grazing of Heather Moorland In North-East Scotland. IV. Seed Dispersal and Plant Establishment in Dung

Article

Aug 1985

David Welch

(1) Germination of seeds on dung deposited at moorland sites was recorded either in situ or in a glasshouse. Colonization by seedlings and peripheral vegetation was observed until plant cover became complete. (2) Many more graminoid than dicotyledonous seedlings appeared on dung of cattle, red deer and sheep. On dung of grouse, hares and rabbits the ratio was roughly equal. Altogether eighty-eight species were recorded as being transmitted by these herbivores, but only Agrostis tenuis*, Calluna vulgaris, Cerastium holosteoides, Juncus spp., Poa pratensis, Rumex acetosella and Sagina procumbens gave numerous germinated seedlings. (3) Many fewer seedlings were found on the dung left in situ than in the glasshouse. Dung deposited in spring also gave rise to fewer seedlings than autumn dung. (4) Seedlings that arose by germination on dung gained much less cover than plants colonizing the deposits vegetatively. However, with cattle dung several transmitted species attained greater cover than in the previously existing vegetation e.g. Cerastium holosteoides, Lolium perenne, Poa annua, Poa pratensis, Rumex acetosella, Stellaria media and Veronica serpyllifolia. (5) Surveys at the moorland sites showed that Anthoxanthum odoratum, Holcus lanatus, Poa annua and Poa pratensis were the grasses most frequently introduced; increase in the number of their establishments was associated with heavy dung deposition by cattle. (6) Estimates were made of the contribution of dunging to the overall impact of the herbivores on the composition of the vegetation. Only with catttle were the effects appreciable, but the gains in cover of graminoids and herbs were less than the decline in Calluna vulgaris (heather) due to plant mortality below the deposits. About a quarter of the greater impact of cattle on heather compared to sheep could be ascribed to dunging.

Grazing Impacts on Litter and Soil Organic Matter in Mixed Prairie and Fescue Grassland Ecosystems of Alberta

Article

Jan 1991

Impacts of long-term cattle grazing on litter and soil organic matter were assessed in mixed prairie, parkland fescue, and foot-hills fescue grasslands of Alberta, Canada. Grazing regimes were of light to very heavy intensities, grazed early, late, and continuously during the growing season. Litter and soil organic matter were sampled in O.l-rnz quadrats and removed as live vegetation, stand-ing Utter, fallen litter, and soil organic matter. Litter and organic matter samples were air dried and sorted by size using sieves and an automatic sieve shaker. Organic carbon content was determined by thermal oxidation. Ground cover was determined using point frames, and heights of standing litter and fallen litter were measured. Heavy intensity and/or early season grazing had greater nep-tive impacts on litter and soil organic matter than did light intensity and/or late season grazing. Under the former regimes there were significant reductions in heights of standing and fallen litter, decreases in live vegetative cover and organic matter mass, and increases in bare ground. More large particle-sized organic matter, particularly standing litter, occurred in controls than in grazed treatments since it would not be removed or trampled by grazing animals. More medium and small particle-sized organic matter occurred in grazed treatments than in ungrazed controls since vegetation likely decomposed more rapidly when it was trampled and broken down as animals grazed.

Small-scale plant species turnover in a limestone grassland – the Carousel model and some comments on the niche concept

Article

Apr 1993
J VEG SCI

This study reports on small‐scale changes in the distribution of plant species in a 2.5 m ² plot of grazed, species‐rich Veronica spicata ‐ Avenula pratensis grassland on shallow, dry, nutrient‐poor soil in the Great Alvar area (Stora Alvaret) of southern Öland, southeastern Sweden. Multivari‐ate analysis of 0.001 m ² and 0.25 m ² quadrats within the plot showed that there is little floristic variation without any trend in the plot. Average species richness varied little throughout the study period from 1986 to 1991 with 1986 averages of 7.0 on 0.001m ² , 16.3 on 0.01 m ² , and 26.1 on 0.25 m ² . On 0.001 m ² the highest species number found was 12, on 0.01 m ² , 27. However, cumulative species richness, i.e. species number in the first year plus new species appearing in later years (averaged over 40 quadrats) increased over the same period, on 0.001 m ² from 7.0 in 1986 to 14.9 in 1991, and on 0.01 m ² from 16.3 to 24.1. Cumulative frequency, i.e. number of quadrats out of 40 where a species occurred in the first year or/and in later years, increased as well; the number of cumulatively highly frequent (> 80%) species increased from 5 in 1986 to 18 in 1991. Species mobility on the scale of the small quadrats used implies both appearance and disappearance from these quadrats. Using six examples, species mobility is shown to vary individualistically, both in rate and degree. We postulate that in homogeneous, grazed, nutrient‐ and water‐deficient environments many species can reach virtually all microsites within the plot, which we express through the idea of the ‘carousel model’. We also question the usefulness of the niche concept and re‐interpret it by stating that all species of this plant community have the same habitat niche, while most of them are short‐lived and have the same regeneration niche. The essential variation amongst the species is their individual ability to establish or re‐establish by making use of favourable conditions appearing in microsites in an unknown, complex spatio‐temporal pattern.

New Insights Into Pasture Diversity: The Consequences of Seed Dispersal in Herbivore Dung

Article

Mar 1996

The dispersal of herbaceous species seeds through herbivorous mammal dung (endozoochory) has been known for some time, although its effect on the grazed communities has not been analyzed in depth. In a Mediterranean grassland, we have found that large quantities of seeds are dispersed in rabbit droppings (Oryctolagus cuniculus L.), with significant effects on the composition and structure of the soil seed reserves. Endozoochorous dispersal encourages the spread of species which lack morphological structures for dissemination, and favours the small-scale spatial diversification of the pasture through the spatial variability of dunging. On a larger scale, however, endozoochory plays a homogenizing role in the plant community through long-distance seed dissemination

Soil compacting impacts on grazing in mixed prairie and fescue grassland ecosystems of Alberta

Article

May 1990
CAN J SOIL SCI

The impacts of long-term grazing on compaction were assessed in mixed prairie and fescue grassland ecosystems of Alberta. Grazing regimes were of light to very heavy intensities, grazed early, late, and continuously during the growing season. Bulk density was measured with a surface moisture/density gauge and a combination moisture/density probe to 65 cm. Penetration resistance to 30 cm was measured with a cone penetrometer. Solonetzic soils were less sensitive to compaction under grazing than Chernozemic soils. Heavy intensity and/or early season grazing had greater impacts on compaction than light intensity and/or late season grazing. Under the former grazing regimes, bulk density increased to 7.5 cm at Kinsella and 65 cm at Stavely; penetration resistance increased to depths of 2.5 cm at Brooks, 15 cm at Kinsella, and 30 cm at Stavely. Heavy trampling versus regular grazing increased penetration resistance to depths of 30 and 10 cm under heavy intensity and/or early season and light intensity and/or late season grazing, respectively. Late season grazing at Brooks and light to moderate grazing at Stavely may be used as management models to reduce compaction under grazing. Trends were not as clear at Kinsella, but light June and autumn grazing had the least compacting effect.

Cattle dung and the fate of Biserrula pelecinus L. (Leguminosae) in a Mediterranean pasture: seed dispersal, germination and recruitment

Article

Jun 1995

Seed dispersal of Biserrula pelecinus via cattle dung in a semiarid pasture is analysed by quantification of the viable seed content of cattle dung, assessment of the percentage of readily germinable seeds in growth chamber of seeds collected from the plant and from dung, monitoring of the on-field frequency of the species in dung pats and in surrounding (control) pasture plots the four springs after dung deposition, and quantification of the pasture area occupied by dung pats. Large amounts of seeds of the species are dispersed by cattle (up to 4 seeds g-1 of dry manure in June 1991), and the germinability of the seeds increases significantly following their passage through the cattle gut (from 2.5% to 9.5%). In the first three springs after deposition, the frequency of adult plant of the species on dung almost tripled that found in the surrounding pasture. The effect on the pasture is scale-dependent and varies considerably between zones depending on the area covered by dung. Thus, presence on dung may explain an average of 8% of the frequency of the species in the pasture at a 10 × 10 cm scale, and up to 20% in some areas. The results are the first evidence of a herbaceous species being greatly favoured in a plant community by its dispersal through herbivore dung, a process that may have profound implications for the interpretation of plant-herbivore relations and on the evolution of plant traits.

Composition and seasonal flux of the soil seed bank of species-rich Themeda triandra grasslands in relation to burning history

Article

Apr 1998
J VEG SCI

John W. Morgan

. Most species-rich grasslands dominated by Themeda triandra in southeastern Australia have been ungrazed and frequently burnt for decades. The seedling emergence technique was used to determine the size and taxonomic composition of the soil seed bank of five grasslands that had different fire histories (i.e. burnt at 1 yr, 3 yr and > 10 yr intervals) and this was compared to the standing vegetation at each site. A nested sampling design (subplot, plot, site) was used to determine the effect of spatial scale on the patterns observed in both the vegetation and the seed bank. Temporal variation in the seed bank was assessed by repeated soil sampling over a two year period. 61 native and 30 exotic species were recorded in the vegetation. Richness varied more between sites than within sites. Sites were therefore internally homogeneous for species richness. However, no correlation between burning frequency and richness was found. DCA ordination separated the sites into distinct groups, but sites with similar fire history did not necessarily group closely. 60 taxa germinated from the soil seed bank, comprising 32 native and 28 exotic species; 11 species, mostly therophytes, were restricted to the seed bank. The richness of the seed bank was significantly lower than the vegetation at all spatial scales. No correlation between seed bank richness and fire history was found. The seed bank of species-rich grasslands is dominated by a limited number of widespread, highly clumped, annual, native and exotic monocots. Most native hemicryptophytes, and perennials in general, were represented in the soil by a transient seed bank. Only 12 % of study species, all therophytes, were considered to form large, persistent seed banks, the size of which was greater in unburnt grasslands at all times of the year. The distinct floristic patterns observed in the vegetation are less clearly represented in the seed bank. The seed bank represents a floristically distinct (and less variable) component of the vegetation when compared to the standing flora. The size of the long-term soil seed bank suggests that it has little functional importance for many native species and probably contributes little to seedling regeneration processes following disturbance. Altering established fire regimes is likely to only change the composition and small-scale richness of the existing site vegetation and will not re-integrate species previously lost from the vegetation due to past management. It is suggested that the maintenance of vegetation remnants and processes that encompass a range of long-term burning histories will be necessary if the flora is to be conserved in situ. Restoration of degraded grasslands cannot rely on the soil seed bank but rather, will be dependent on the reintroduction of propagules.

Levels of germinable seed m topsoil and cattle faeces in legume-grass and nitrogen-fentlized pastures in South-East Queensland

Article

Jan 1991
AUST J AGR RES

Measurements were made of germinable seed of all species in the top 5 cm of soil beneath 9 paddocks in an 11-year-old pasture experiment in south-east Queensland. The experiment comprised two pasture types grazed by cattle: legume-grass (Macroptilium atropurpureum- Setaria sphacelata) pastures grazed at four stocking rates and nitrogen fertilized S. sphacelata pastures grazed at five stocking rates. Levels of germinable seed in the soil varied with pasture type and stocking rate and ranged from 6760 to 45480 seeds/m2. Seed reserves increased on the legume-grass pastures as stocking rate increased. Fifty-seven different plant species were identified from the seedlings grown from the soil seed reserve. For 11 of these species, which contributed 70% of the seed reserves, there were significant trends in relation to pasture type and/or stocking rate. The only species where seed reserves significantly decreased with increasing stocking rate were the two sown species. Cattle faeces were also collected from lightly and heavily stocked legume-grass and nitrogen-fertilized pastures in spring, summer, autumn and winter. Germinable seed contents of all species were measured. Seed content of faeces was higher in the summer and autumn than in the winter and spring samplings, and in the heavily stocked than in the lightly stocked pastures. The highest content recorded was 20.5 germinable seeds g-1 faecal dry matter. The species with the highest germinable seed content in faeces were Digitaria didactyla, Axonopus affinis and Eleusine indica, the latter being restricted to nitrogen-fertilized pastures. Seed dissemination in faeces is a factor contributing to the invasiveness of prostrate perennial grasses such as D. didactyla and A. affinis under heavy grazing.

Influence of sheep rxcreta on pasture uptake and leaching losses of sulfur, nitrogen and potassium from grazed pastures

Article

Jan 1993
AUST J SOIL RES

In situ mini-lysimeters with ion exchange resin traps were used to measure the effect of dung and urine return on pasture growth and pasture uptake and leaching losses of sulfur (S), nitrogen (N) and potassium (K) in hill pastures grazed by sheep.Single dung or urine events in winter boosted pasture production by 37% and pasture uptake of S, N and K by up to 35%, 55% and 57%, respectively, during the following year. Whereas the late summer single superphosphate application increased late spring and mid summer pasture growth of the following year only, dung or urine return increased pasture growth in every season of the following year. Despite the addition of 11.5, 4.7 and 376 kg of readily available S, N and K ha-1 in a single dung event and 14.5, 28.5 and 146 kg of S, N and K ha-1 in a urine event, accelerated leaching of S, N and K did not occur from dung or urine affected soil. Less than 3 kg S, 0.5 kg N and 2 kg K ha-1 were lost by leaching from dung or urine affected soil. The majority of S, N and K from excreta remained in the soil, either immobilized in soil organic matter and/or adsorbed on to soil sesquioxide surfaces and cation exchange sites with the equivalent of only 1.6% of S, 4.4% of N and 9.0% of K from dung and 29% of S, 18.7% of N and 31% of K from urine being recovered in increased pasture uptake over a period of one year. Under the climatic conditions that prevailed after the winter deposition of excreta, immediate loss of excreta-derived nutrients was negligible but urine deposition markedly accelerated the leaching losses of native soil calcium and magnesium (8 kg Ca and 2.9 kg Mg ha-1 from urine and 6.4 kg Ca and 2.4 kg Mg from dung, respectively). Quantitative information of this kind is important for determining the long-term sustainability of soil fertility in grazed pastures before a comprehensive understanding of pasture nutrient cycles is complete.

Soil Seed Bank Composition along a Gradient from Dry Alvar Grassland to Juniperus Shrubland

Article

Apr 1996
J VEG SCI

Dry alvar grasslands on limestone on the Baltic island of Öland, SE Sweden, are very species-rich as long as the traditional agricultural exploitation of grazing and fire wood collection continues. After abandonment, encroachment of Juniperus communis starts and a closed woodland can develop within 100 yr. A chronosequence, representing a successional series, was used for the comparison of sites still grazed, and sites ungrazed for about 20, 55 and 80 yr, respectively. Out of the 58 characteristic dry alvar grassland species 55 % disappeared from the established vegetation after 80 yr of abandoning, and 80 % also vanished from the seed bank. Arenaria serpyllifolia, Trifolium repens, Agrostis vinealis, Linum catharticum, Polygala vulgaris, Cerastium fontanum, Luzula campestris, Achillea millefolium and Potentilla tabernaemontani were the only species left in the seed bank. More than 75 % of the dry alvar grassland species were classified as having a transient or short-term persistent seed bank. It is concluded that restoration management, by cutting junipers, of overgrown dry alvar grassland cannot rely on the longevity of seeds in the soil. Seeds have to be dispersed by wind or grazing animals.

Studies in the Grazing of Heather Moorland in North-East Scotland. II. Response of Heather

Article

Apr 1984

David Welch

(1) Trends in heather cover, height and standing crop were observed at thirty-two sites for periods of at least 4 years. Occupance by larger herbivores (cattle, deer, grouse, hares, rabbits, sheep) was monitored from the volumes of dung deposited. (2) Heather trends were regressed on deposition rates and other factors likely to affect response. Transforming percentage cover by logits and including an index of growth improved goodness-of-fit substantially. (3) The estimated rates of dung deposition causing zero heather trend were little changed by the addition of regression variables, but confidence limits narrowed. Zero trend in cover resulted from a lower deposition rate than zero trend in height and standing crop. (4) Various ways of sub-dividing total dung were examined to expose possible differences between herbivores or seasons. The most satisfactory treatment giving stable regression coefficients was to partition non-cattle deposition around threshold levels. Cattle had the most severe impact, and heavy usage by other herbivores also significantly reduced heather, but light usage had a significant positive effect. (5) Selectivity in defoliation between food plants accounted for only a modest part of the variability in heather response. Its importance seemed greatest in lagomorphs, but cattle affected heather in ways unrelated to the observed utilization. (6) The stocking rates above which heather declines are estimated as 0.2 cattle and 2.7 sheep ha-1, given average growth of 4.7 cm year-1 and a normal amount of light usage from other herbivores. With 1.2 cattle ha-1 cover would decline by 32% in 4 years, and in 10 years from 80 to 5%; a stocking of 5 sheep ha-1 would cause a decline of only 9% over 4 years.

Soil seed bank and species turnover in limestone grassland

Article

Feb 1994
J VEG SCI

The vegetation and soil seed bank in a limestone grassland in southern Sweden were studied in permanent 1‐m ² subplots which had been either grazed or not grazed for 17 yr. Of the 92 species recorded, 18 were present only in the seed bank, 28 were more frequent and 24 were less frequent in the seed bank than in the vegetation and 22 were not detected in the seed bank. Among the species present in the seed bank, therophytes were over‐represented. Species turnover in the vegetation was estimated from presence/absence data collected in 1980, 1986 and 1990. Turnover was high, but there were no differences between grazed and ungrazed subplots. The turnover for individual species was also high in many cases. There was no clear relationship between the turnover of a species and its presence in the persistent seed bank.

Establishment of pasture species on cattle dung: The role of endozoochorous seeds

Article

Feb 2009
J VEG SCI

The process of colonization of cattle dung patches and its relation to endozoochorous dispersal is analysed in a Mediterranean pasture. Dung pats dropped in spring and winter were marked, and the vegetation developing on them during the first two years of colonization was followed. The influence of endozoochorous seeds on dung colonization is assessed through the study of: (1) the vegetation on spring and winter dung pats and the seed contents of both, which is abundant in the former and negligible in the latter; and (2) the vegetation on spring dung pats compared with that of the surrounding pasture. The origin of plants growing on dung (either seeds in the manure or in the soil seed bank) was traced by studying dung colonization under controlled conditions in pots with manure put on seed-free sand, and on pasture turf. The results indicate that endozoochorous seeds germinate in manure; they are the main source of recovery in gaps generated by dung pats. The micro-succession involved is independent of the type of pasture. A small-scale spatial pattern results in which gaps of old dung are dominated by endozoochorous species. Thus, dung patches enhance the similarity between grazed communities, and the variation within communities.

Viable grass seeds in herbivore dung from a semi‐arid grassland

Article

Apr 2006
GRASS FORAGE SCI

Faeces of cattle, pronghorn and rabbit were collected from the Central Plains Experimental Range, Colorado, 6, 18 and 30 months after being excreted. The faecal material was placed in moistened potting soil and seedling emergence observed. Bouteloua gracilis (blue grama grass) and Sporobolus cryptandrus (sand drop seed), emerged in abundance from cattle dung. Emergence of B. gracilis decreased with increasing period of exposure before collection, but emergence of S. cryptandrus increased with exposure. Forbs dominated the seedling populations in pronghorn dung, and few seedling populations of any species emerged from rabbit dung. The results are discussed in relation to the effect of large herbivores on the establishment of species from seed in rangeland.

Soil seed bank and community dynamics in an annual‐dominated Mediterranean salt‐marsh

Article

Jun 1998
J VEG SCI

Teodoro Marañón

The seed bank in the soil and litter of an annual grassland in the upper salt marsh of the Guadalquivir delta (SW Spain) contained on average 49110 seeds/m ² ; 29 species were represented. Field censuses of the grassland, in two consecutive springs, yielded 7 410 and 9 520 plants/m ² respectively. A combined Correspondence Analysis of the seed bank samples and field censuses showed differences in grassland composition between wet and dry years. The environmental changes induced different expressions of the soil seed bank, mediated by demographic processes. The effect of salinity (25 dS/m of NaCl) was studied on intact soil blocks transplanted to a greenhouse. Salinity did not affect the emergence of seedlings, but reduced the growth of the dominant species, Trisetaria panicea. The importance of the role of seed banks in community dynamics and their use for conservation management are discussed.

Transect‐based patch size frequency analysis

Article

Nov 1997
J VEG SCI

A new, transect‐based patch size detection method for species pattern is proposed which improves results obtained with methods described earlier. The method was tested on an extensive artificial data set together with three of the existing methods considered best: Two and Three Term Local Quadrat Variance (T2LQV and T3LQV) and New Local Variance (NLV). The TLQV methods recovered only some of the existing patterns and were heavily dependent on inter‐patch distances, whereas NLV almost always produced curves with oscillations. In addition a significance test is proposed, while such a test is seldom found in the earlier methods. Our method, PASFRAN, determines the frequencies of runs with 1, 2, 3, etc. quadrats containing a certain species and compares those with frequencies based on Monte Carlo simulated random configurations. The comparison is performed for each run length and the significance of the deviation between observed and expected frequencies can be calculated on the basis of a large number of simulations. Because this approach may be considered a case of multiple testing, a Bonferroni correction on the significance level was applied. The method can also be used for the detection of inter‐patch distances. In addition, run lengths can be grouped and the test can be applied to the frequencies of combinations of run lengths. The method can detect dominance patches when quantitative data on the occurrence of plant species are available. In the same way, it can detect multi‐species patterns using sample scores from an ordination analysis such as correspondence analysis. An extension towards composite, higher‐order patterns is under investigation. The new method appeared to be effective in recovering artificial patterns, while it is not influenced by the relative values of patch size and inter‐patch distance. When applied to the distribution of cow dung patches and certain plant species along a transect of 500 quadrats of 10 cm × 10 cm in an alvar limestone grassland, it produced straightforward and realistic results as compared with other methods and field impressions.

Changes in plant species richness in a calcareous grassland following changes in environmental conditions

Article

Dec 1994

Renate Huber

This study presents results of a three and a half year experiment in a calcareous grassland on the Baltic island of Öland, south-eastern Sweden. Environmental conditions, viz. nutrient regime, water availability, light conditions and grazing pressure were changed in a randomised experimental design with ten different combinations of these factors, including a control. Weather conditions during the study period fluctuated considerably. Only the combination of reduced light and increased soil nutrient availability decreased species richness significantly, presumably by inducing asymmetric competition for light by competitively strong species. Physical space also became less available for weaker competitors. In cases where only nutrients or only water were supplied in sufficient amounts, competitive exclusion was inhibited by either low nutrient or low water availability. Under conditions which combined high levels of nutrient and water supply with regular disturbance (i.e. simulated grazing) high species richness was maintained. Although there was a significant negative correlation between species richness and amount of above-ground biomass, the number of species was not significantly reduced in the treatment which combined fertilisation and irrigation. One reason for this may be that the heterogeneous light regime in this treatment still allowed species persistence and coexistence.

Small-scale species patterns and associations in an alvar limestone grassland on Öland, Sweden

Article

Jun 1998

Xiaobing Dai

This paper reports on the results of a transect analysis carried out in order to detect small-scale patterns ofAvenetum species in a limestone grassland on the Great Alvar on the Baltic island of Öland, Sweden. Three transects consisting of 500 10×10 cm quadrats were used. The cover and number of flowering stalks (if any) of the 21 most common species were recorded. In addition the total cover of vascular plants, cover of mosses and lichens, cover of cow dung and soil depth in each quadrat were recorded. Ellenberg indicator values for light, moisture, reaction and nitrogen were calculated for each quadrat as weighted averages of the values for the species included in the analysis. Patch size frequency analysis, PASFRAN, a new method for detecting patches and their sizes, revealed that 42% of all significant species patches detected had mean patch sizes (diameter) in the range of 26–50 cm, which matched the size of dung patches—49 cm in transect 1 and 30 cm in transect 2. Results of association analysis revealed correlations for several species pairs and between species and environmental factors with similar patch sizes. Combination of PASFRAN and association analysis is recommended as an effective method for pattern detection.

Herbivorous mammals as seed dispersers in a Mediterranean dehesa

Article

Oct 1995

Endozoochrous seed dispersal by herbivorous mammals has been verified repeatedly and its possible influence on the structure and function of herbaceous communities has been suggested. Quantitative studies, however, are lacking in the field of seed dispersal via the dung of herbivore guilds in little-altered environments. The present paper analyses seed dispersal via rabbit, fallow deer, red deer and cow dung in a Mediterranean dehesa (open woodland used for hunting and ranching) during the seeding season. Dung seed content was determined by the glasshouse cultivation of eight dung samples from each herbivore, collected fortnightly between February and August. The four herbivores disperse many seeds (spring averages are 6–15 seeds per gram of dry dung and maxima of 25–70) from a large number of species (totals between 52 and 78). Dispersal seems to be mainly determined by seed production of the plant comminity. This is reflected in (i) the dissemination of a high percentage of the species present in the dehesa, (ii) great seasonal variability, related to seed production, in the amount of seeds and number of species dispersed, and (iii) a high semi-quantitative similarity of seed content in the four types of herbivore dung throughout the year. There is also important quantitative variation that depends on animal traits and feeding habits. These results and the characteristics of species found in dung suggest the adaptation of plant species to the dispersal of their seeds via herbivore gut. This process may well have profound implications for vegetation dynamics and the evolution of plant traits.

Comparative Plant Ecology. A Functional Approach to Common British Plants

Article

Jan 1988

Effect of run-off water retention and grazing on soil and on vegetation of a temperate humid grassland

Article

Feb 1993
AGR WATER MANAGE

A 4-year field trial was carried out on a Typic Natraqualf to modify the surface run-off, to change the soil water regime and improve forage productivity. Water was retained by earth banks which were built along contour lines. The area was grazed by cattle at a density of six animal units per hectare during five or six occupation periods per year. To study the effect of cattle trampling, 1 ha within the water retention area was excluded from grazing.It was found that surface accumulation of water led to higher soil water contents and prevented salt ascension by capillarity from the water table (Electrical Conductivity of A1 horizon, 1.4 dS·m−1 against 3.4 dS·m−1 in the control area). Soil salinization in the control area was associated with soil water evaporative losses and the water table depth, when it was less than 1.5 m deep. Soil alkalinity (pH and SAR) showed variations closely related to salinity. The already impaired soil physical properties were not significantly affected by livestock trampling in the water retention area.A dramatic change in plant community composition was observed. Most halophitic species disappeared and the area was covered by hydrophilous grasses. This determined a 4-fold increase in higher quality forage. Run-off water retention proved to be a promising way to change temporarily the status of the soil and to cause a large change in grassland characteristics and productivity.

Vegetation development and sheep grazing in limestone grasslands of south Öland, Sweden. Acta Phytogeogr

Jan 1982
1-104

E Rosén

Rosén, E. 1982. Vegetation development and sheep grazing in limestone grasslands of south Öland, Sweden. Acta Phytogeogr. Suec. 72: 1-104.

The role of regeneration by seed in the dynamics of limestone grassland communities

G Rusch

Rusch, G. 1993. The role of regeneration by seed in the dynamics of limestone grassland communities. Disser-tation Uppsala University.

Effects of cattle dung deposition on energy and matter flows in bahiagrass (Paspalum notatum Fluegge) pasture. I. Changes in sward height and consumed herbage was related to rate of dung disappearance

Jan 1988
371-386

M Hirata
Y Sugimoto
M Ueno

Hirata, M., Sugimoto, Y. & Ueno, M. 1988. Effects of cattle dung deposition on energy and matter flows in bahiagrass (Paspalum notatum Fluegge) pasture. I. Changes in sward height and consumed herbage was related to rate of dung disappearance. J. Jpn. Soc. Grassl. Sci. 33: 371-386.

Some short-term changes in the dynamics of limestone grassland of south Öland, Sweden. Acta Univ. Ups. Nova Acta Regiae

Jan 1984
189-205

E Rosén

Rosén, E. 1984. Some short-term changes in the dynamics of limestone grassland of south Öland, Sweden. Acta Univ. Ups. Nova Acta Regiae. Soc. Sci. Ups. Ser. V C 3: 189-205.

The soil seed banks of north west Europe: methodology, density and longevity

Jan 1997

K Thompson
J Bakker
R Bekker

Thompson, K., Bakker, J. & Bekker, R. 1997. The soil seed banks of north west Europe: methodology, density and longevity. Cambridge University Press, Cambridge.

Small-scale plant Dai, X. species turnover in a limestone grassland: the carousel model and some comments on the niche concept Transformation of cover-abundance values in phytosociology and its effects on community similarity

Jan 1964
179-188

T G Tutin

Tutin, T.G. et al. 1964-1980. Flora Europaea. Cambridge University Press, Cambridge. van der Maarel, E. & Sykes, M.T. 1993. Small-scale plant Dai, X. species turnover in a limestone grassland: the carousel model and some comments on the niche concept. J. Veg. Sci. 4: 179-188. van der Maarel, E. 1979. Transformation of cover-abundance values in phytosociology and its effects on community similarity. Vegetatio 39: 97-114.

Small scale spatial pattern of core species in a limestone grassland in the Great Alvar on the Baltic island Öland, Sweden

Jan 1998
147

Vegetation development and sheep grazing in limestone grasslands of south Öland, Sweden

Jan 1982
1

Rosén E.

Jan 1988
371

Hirata M.

Some short‐term changes in the dynamics of limestone grassland of south Öland, Sweden

Jan 1984
189

Rosén E.

Impact of cattle dung deposition on the distribution pattern of plant species in an alvar limestone grassland

Abstract

No full-text available

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