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Hypothetical examples of logistic models to illustrate how they can quantify dynamic effects across space and/or time. Panel a represents a random-intercept (equation 1) and panel b represents a random coefficient (equation 2). For each model, the marginal (black line) and conditional (grey lines) predictions are shown. In these two examples, the fixed effects are the same and thus the marginal predictions are the same. The difference lies in the incorporation of conditional random effects, which allows for different forms of responses to occur across space or time. doi:10.1371/journal.pone.0074520.g002
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Across the planet, high-intensity farming has transformed native vegetation into monocultures, decreasing biodiversity on a landscape scale. Yet landscape-scale changes to biodiversity and community structure often emerge from processes operating at local scales. One common process that can explain changes in biodiversity and community structure is...
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... we added transect (n = 12) as a random variable to each model to account for spatial autocorrelation among traplines within transects and to better account for spatial variation in small communities across the edge among sites. To do so, we extended the models developed by Ewers and Didham [19] to allow for random intercepts (an additive effect of transect emphasizing different magnitudes of edge effects among transects) and random coefficients (allowing for different magnitude and extent of edge effects among transects; Figure 2). This extension is beneficial for three reasons. ...
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... Further, animals that utilize closed canopy areas can persist within the longleaf pine woodland if some hardwood patches remain. Several studies have identified fine-scale heterogeneity as important for maintaining bird, small mammal, invertebrate, and reptile diversity, but rarely for larger vertebrates (Batary & Baldi, 2004;Hurst et al., 2013;Lang et al., 2002;Magura, 2002;Reynolds et al., 2018). Understanding how species respond to edges at fine scales is important in maintaining diverse wildlife communities within longleaf pine ecosystems and can improve restoration efforts (Goodrich & Buskirk, 1995;Linnell & Strand, 2000;Means, 2007). ...
Restoring and maintaining biodiversity in a changing world is increasingly challenging due to the competing needs of species for suitable space and resources. One ecosystem that has seen considerable anthropogenic changes in extent and structure is the longleaf pine (Pinus palustris) ecosystem. Understanding how wildlife responds to restoration is important to informing forest restoration and conservation. We monitored game birds and mid‐large‐sized mammal occupancy in and around hardwood patches embedded within a longleaf pine woodland at The Jones Center at Ichauway in Newton, GA. We found that 11 species use the transition zone between the longleaf pine and hardwood hammocks. Gray squirrels (Sciurus carolinensis), Virginia opossums (Didelphis virginiana), and nine‐banded armadillos (Dasypus novemcinctus) occupancy increased along the gradient while fox squirrel (Sciurus niger) declined. Our results suggest that oak patches and transitional zones are important to maintaining biodiversity within the longleaf pine ecosystem.
... Evidence suggests that due to fragmentation, 70% of global forest lies within 1 km of the forest edge (Haddad et al., 2015). Agricultural land can have adverse impacts upon biodiversity at considerable distances into natural habitats (Hurst et al., 2013;Scriven et al., 2018). Therefore, biodiversity levels in reference sites would be influenced by factors such as proximity to agricultural land, patch size, connectivity, edge effects and the intensity of land use in the surrounding matrix (Prugh et al., 2008). ...
Biodiversity underpins all food production and strengthens agricultural resilience to crop failure. However, agricultural expansion is the primary driver of biodiversity loss, particularly in the tropics where crop production is increasing and intensifying rapidly to meet a growing global food demand. It is therefore crucial to ask, how do different crops and crop production systems impact biodiversity?
We first use the FAO database of harvested crop area to explore temporal changes in crop area and intensification across the entire tropical realm. We show that the harvested area of tropical crops has more than doubled since 1961, with ever‐increasing intensification. The harvested area in 2019 was 7.21 million km², equivalent to 5.5% of global ice‐free land area, or 11.5% of land area in the tropics.
Second, we conducted a meta‐analysis of 194 studies and 1364 pairwise comparisons to assess the impact of tropical agriculture on biodiversity, comparing biodiversity values in food crop sites versus natural reference habitats.
Our meta‐analysis shows that crop type, rotation time and level of shading are important determinants of biodiversity assemblages. Perennial tropical crops that are grown in shaded plantations or agroforests (e.g. banana and coffee) support higher biodiversity, while crops cultivated in unshaded and often homogeneous croplands (e.g. maize, sugarcane and oil palm), and particularly annual crops, have impoverished biodiversity communities.
Policy implications. Our findings highlight the increasing agricultural expansion and intensification over the last 60 years and inform our understanding of how different crops and crop production systems impact biodiversity. Furthermore, they provide insight into the long‐term sustainability of tropical food production and may serve as a warning sign for agricultural systems that rely on the ecosystem services provided by biodiversity.
... The dominance of M. natalensis in cultivated fields has also been reported by other researchers Mayamba et al. 2019;Mlyashimbi et al. 2019), and is the most important rodent pest species in agricultural crops in sub-Saharan Africa (Swanepoel et al. 2017). M. natalensis is abundant in cultivated fields because of its adaptability as a generalist and rapid rate of colonization (Hurst et al. 2013;Mayamba et al. 2019). ...
The multimammate mouse, Mastomys natalensis, is the most common rodent pest species in sub-Saharan Africa. Currently, rodenticides are the preferred method used to reduce the population of rodent pests, but this method poses direct and indirect risks to humans and other non-target species. Fertility control is a promising alternative that has been argued to be a more sustainable and humane method for controlling rodent pests. In this study, we compared the effectiveness of fertility control bait EP-1 (quinestrol (E) and levonorgestrel (P), 10 ppm) and an anticoagulant rodenticide bait (bromadiolone, 50 ppm) on the population dynamics of M. natalensis in maize fields in Zambia during two cropping seasons. M. natalensis was the most abundant species in maize fields (77% of total captures). Fertility control reduced the number of juveniles and suppressed population growth of M. natalensis at the end of the 2019–2020 cropping season. The population density initially decreased after rodenticide treatment, but the population rapidly recovered through immigration. None of the treatments influenced maize damage by rodents at germination (F 2,67 = 1.626, p = 0.204). Applying the treatments during the maize seeding time was effective at suppressing population growth at the end of the cropping season than application the month before maize seeding. This research indicates that a single dose delivery of EP-1 and rodenticide have comparable effects on the population dynamics of M. natalensis. These findings are important in developing fertility control protocols for rodent pest populations to reduce maize crop damage and improve yields.
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... Connectivity refers either to the spatial relationship between patches in a landscape (structural connectivity) or the ability of the landscape to facilitate the movement of species between patches (functional connectivity), and is considered important for species population persistence within fragmented landscapes (Hurst et al. 2013;Correa Ayram et al. 2016). When patch size is small, a species' persistence may rely solely on its ability to disperse, which depends largely on the type of habitat adjacent to and between patches (Brooker et al. 1999;Söndgerath and Schröder 2002;Turgeon and Kramer 2012). ...
... Reserves with the highest connectivity scores, characterized by long permeable boundaries (>5 km) to mixed use landscapes or direct connections to extensive areas of suitable natural habitat had the highest observed and predicted levels of mammal species richness. This finding supports previous research showing that the amount of suitable habitat adjacent to a patch is important for maintaining biodiversity (Crooks 2002;Hurst et al. 2013;Correa Ayram et al. 2016;Fahrig et al. 2019). Access to large amounts of suitable habitat improves both survival and reproduction (Jewitt et al. 2015) while large corridors allow for ease of dispersal and the re-colonisation of small reserves that are vulnerable to stochastic local extinction events (Tischendorf and Fahrig 2000;Boscolo and Metzger 2011;Fahrig et al. 2019). ...
... Mammal species richness recorded in this study varied widely within the 12 CCT nature reserves surveyed but collectively they currently provide a refuge for 19 surviving medium and large mammal species. As natural habitat is lost from the landscape, small reserves, in addition to enhancing connectivity, can increase matrix quality through the retention of natural habitat in the landscape, which benefits species richness and abundance in reserves and fragments (Hurst et al. 2013;Correa Ayram et al. 2016). ...
Urbanisation is associated with the loss and fragmentation of natural land, the disruption of ecosystem functioning and services, and the loss of biodiversity. Cape Town is situated in a global biodiversity hotspot, with high rates of endemism, but both agricultural and housing demands are increasing pressure on remaining patches of natural land and consequently the biodiversity they support. The aims of this study were to use a standardised camera trap survey to determine which native medium and large mammal species still survive in 12 City of Cape Town (CCT) municipal reserves (range 32–8400 ha), and to understand how reserve size, area-perimeter ratio, connectivity, habitat heterogeneity and presence of permanent freshwater aquatic habitat might influence medium and large mammal (>0.5 kg) community composition. Cameras were placed at 151 locations across all reserves using a stratified placement protocol that resulted in 13,360 independent trigger events by targeted taxa. Nineteen native species (11 carnivores, 7 herbivores, 1 omnivore) were recorded, which is 49% of the 39 species believed to have been present historically. Species richness varied from 1 to 12 species (mean ± SD = 7 ± 3.6) across reserves, and linear models showed that higher species richness and the presence of large carnivores was best explained by improved connectivity to large amounts of natural habitat. It is recommended that maintaining biodiversity in urban reserves will be best achieved by preserving and establishing corridors of suitable habitat that allow for the movement of animals to and from other patches.
... One of the major cash crops grown in tropical and subtropical Africa is sugarcane, which is often cultivated in large commercial monoculture plantations (Kalinda and Chisanga, 2014). Commercial sugarcane plantations tend to favour generalist species, while specialists often do not persist, thus reducing biodiversity (Hurst et al., 2013;Reynolds et al., 2018;Smith et al., 2015). While this highlights the broad-scale effects of agricultural landscapes, there is still limited information regarding how heterogeneity within a particular farm or plantation may alter these outcomes (Mamba et al., 2019). ...
Agricultural intensification is a threat to terrestrial ecosystems around the world. Agricultural areas, especially monocultures, create homogenous landscapes for wildlife. However, certain crops, such as sugarcane, are harvested in phases, creating a mosaic of fields in different stages of growth. We investigated changes in avian communities across four different sugarcane growth stages: emerging, short, medium and tall sugarcane, as well as control sites that represented native savanna habitat in northeast Eswatini prior to conversion to agriculture. In total, we sampled nine sites in sugarcane fields (at different growth stages) and three in native savanna. We conducted bird counts at 5-week intervals along 200m line transects over both the breeding and non-breeding seasons. We recorded a total of 124 bird species belonging to 58 families. Bird species richness and diversity were higher in savannas compared to any stages of growth in sugarcane. In contrast, functional beta diversity and uniqueness were higher in sugarcane than in savanna. Community composition was also different between the two land-uses. While there was overlap in bird species composition between different sugarcane growth stages, there was high beta diversity and high turnover between sites, indicative of the high temporal and spatial variability in bird communities in sugarcane fields. We demonstrated that the spatial and temporal variability created by the different growth stages of sugarcane promotes the occurrence of species with different traits, which may contribute to ecosystem functioning and promote the conservation of bird species as sugarcane fields can provide resource complementation for species with different needs.
... In the last decades, natural habitats worldwide have been suppressed or altered by croplands, consistently leading to biodiversity losses (Foley et al. 2005;Laurance et al. 2014). Croplands also reduce biodiversity in adjacent forest environments through edge effects, which is a degradation of forest borders (Hurst et al. 2013;Laurance et al. 2014). Although biodiversity loss at the community-level is a general effect of croplands, population-level responses may vary between species depending on whether and how species use resources provided by crops Braga et al. 2015). ...
Small rodents rely on resource gathering during the breeding season to support their reproductive output and offspring survival. Since croplands may provide complementary food sources, we evaluated the influence of the presence of cornfield on the forest edge in Oligoryzomys nigripes (Olfers 1818) abundance and breeding. We found that abundance, proportion of reproductive females and males, as well as the number of juveniles were higher in the cornfield-forest edges, with no seasonality, a pattern divergent from the seasonal reproduction described for the species. Therefore, our results supported the hypothesis of cornfields benefiting O. nigripes abundance and breeding success.
... In the last decades, natural habitats worldwide have been suppressed or altered by croplands, consistently leading to biodiversity losses (Foley et al. 2005;Laurance et al. 2014). Croplands also reduce biodiversity in adjacent forest environments through edge effects, which is a degradation of forest borders (Hurst et al. 2013;Laurance et al. 2014). Although biodiversity loss at the community-level is a general effect of croplands, population-level responses may vary between species depending on whether and how species use resources provided by crops Braga et al. 2015). ...
Small rodents rely on resource gathering during the breeding season to support their reproductive output and offspring survival. Since croplands may provide complementary food sources, we evaluated the influence of the presence of cornfield on the forest edge in Oligoryzomys nigripes (Olfers 1818) abundance and breeding. We found that abundance, proportion of reproductive females and males, as well as the number of juveniles were higher in the cornfield-forest edges, with no seasonality, a pattern divergent from the seasonal reproduction described for the species. Therefore, our results supported the hypothesis of cornfields benefiting O. nigripes abundance and breeding success.
... Fig. 1). Mbuluzi Game Reserve is a conservation area that is explicitly managed for the conservation of wildlife (Hurst et al., 2013). Simunye town borders the conservation area and is characterized by peri-urban land-use, while Tabankulu village is located on a large-scale sugar cane plantation. ...
Infectious diseases vary in prevalence and pathology among host species. Species may differ in prevalence of infection due to varying exposure and susceptibility to disease agents throughout their lifetime, which may be attributable to underlying differences in their phenology, physiology and behavior. A recently growing body of literature has focused on the utility of host life-history traits to provide mechanistic explanations for interspecific variation in host-parasite associations. In this study, we utilized diverse avian and haemosporidian assemblages in an African savanna to evaluate the link between haemosporidia prevalence (Plasmodium, Haemoproteus, Leucocytozoon) and avian life-history traits such as body size, mating system, nest care and nest structure. We found that variation of haemosporidia prevalence was consistent with life-history traits that pertain to the reproduction of avian host. Nest care was the single most important predictor of infection status. In birds with shared and female-only nest care, the expected rates of parasitism were between 8- and 12-fold higher than in avian brood parasites that provide no nest care. This finding supports the hypothesis that parental care is an evolutionarily costly life-history trait that increases species risk of infection with vector-borne diseases. The influence of other host traits (nest structure, body size) was less consistent suggesting that differences in the vectors’ ecology and host-seeking behavior produce variable patterns of parasitism among haemosporidia genera. Nest structure influenced infection with Haemoproteus and Leucocytozoon only. Leucocytozoon infections were associated with ground-nesting birds, while Haemoproteus infections with birds that build open nest structures. Body size was an important predictor of Leucocytozoon infections, particularly large-bodied birds like guineafowl and doves, which exhibited high prevalences.
... Human-induced wildland alterations for agriculture are ubiquitous and commonly implicated in compromising vertebrate biodiversity. These alterations can impede ecological processes and ecosystem services (Crist et al. 2017, Bailey et al. 2016, Hurst et al. 2013. Landscape fragmentation and alteration, such as crop cultivation, can form anthropogenic barriers where native vegetation communities and altered lands meet (hereafter edges), consequently hindering wildlife movement (Crooks et at. ...
... This study's objectives were to understand how small mammals belonging to different functional groups-Mastomys natalensis (generalist) and Lemniscomys rosalia (specialist)move across edges in the landscape mosaic lowveld of Eswatini, through small mammal translocations. Mastomys natalensis is a generalist omnivore that often inhabits agriculture such as sugarcane (Hurst et al. 2013, Hurst et al. 2014. Mastomys natalensis is nocturnal, with a high tolerance of varying habitats, and is often considered a pest in agriculture and homesteads (Skinner & Chinimba 2005). ...
... Mastomys natalensis is nocturnal, with a high tolerance of varying habitats, and is often considered a pest in agriculture and homesteads (Skinner & Chinimba 2005). Lemniscomys rosalia is a mixed granivory-herbivory specialist that is uncommon in agricultural areas (Hurst et al. 2013, Hurst et al. 2014. Lemniscomys rosalia is diurnal, crepuscular, and occupies a wide variety of native vegetation types (Skinner & Chinimba 2005). ...
Human-induced landscape alteration by agriculture is ubiquitous and impacts ecological processes and ecosystem services. The link between altered and native vegetation (hereafter edges) can create anthropogenic barriers for wildlife movement. Movement response to edges is dependent on landscape and functional group characteristics that shape spatial behavior in individuals; and affect population dynamics, dispersal, diversity, gene flow, and nutrient distribution. Few studies exist on small-mammal functional group movement response to edges, despite its integral role in behavioral and ecological processes. I analyzed the effect of altered land use on movement response in African savannah generalist Mastomys natalensis and specialist Lemniscomys rosalia. Each species was live-trapped for 2 months at 8 sites, across 2 boundary classes—homestead agriculture vs. savannah and commercial agricultural vs. savannah. Twelve individuals of each species were tracked and translocated at each transect with alternating treatments. Movement characteristics by M. natalensis showed a preference for altered land-use areas, possibly due to resource utilization. Conversely, L. rosalia showed a definitive trend (80%) to avoid edge crossing, regardless of abutting vegetative community, possibly due to their inability to cross and utilize altered landscapes. These results support the a priori hypothesis that altered land-use areas greatly impact specialists moving across the edge but only minimally affect generalist movements. Altered landscapes can affect small mammal movements and have cascading effects that alter vegetative and faunal communities.
... Efecto de borde sobre roedores y sus ectoparásitos en un bosque templado de San Francisco Oxtotilpan, Estado de México, México Introducción La estructura de las comunidades biológicas está influenciada por la heterogeneidad ambiental, es decir, a medida que las condiciones ambientales se modifican de un sitio a otro, las especies y las interacciones entre estas se pueden ver alteradas (Smith y Smith 2006). El crecimiento de la población humana ha ocasionado que espacios naturales sean fragmentados alterando la diversidad biológica (Hurst et al. 2013). ...
Efecto de borde sobre roedores y sus ectoparásitos en un bosque templado de San Francisco Oxtotilpan, Estado de México, México Introducción La estructura de las comunidades biológicas está influenciada por la heterogeneidad ambiental, es decir, a medida que las condiciones ambientales se modifican de un sitio a otro, las especies y las interacciones entre estas se pueden ver alteradas (Smith y Smith 2006). El crecimiento de la población humana ha ocasionado que espacios naturales sean fragmentados alterando la diversidad biológica (Hurst et al. 2013). En la actualidad, la fragmentación de ecosistemas es una de las principales causas de disturbios para la biodiversidad (Santos y Tellería 2006) y las interacciones ecológicas (Bordes et al. 2015). La conversión de la vegetación nativa a zonas de cultivo genera límites con diferentes contrastes por el borde, el cual, puede ser definido como la diferencia en la composición o estructura entre ecosistemas conjuntos, este efecto de borde es un elemento clave en el movimiento de los animales (Murcia 1995, Villaseñor et al. 2014), es por esto que el presente trabajo pretende analizar la riqueza y diversidad de roedores y sus ectoparásitos y el efecto que el borde tiene sobre ellos.
