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Ecology and conservation of butterfly metapopulations in the fragmented British landscape
Abstract
Over the past 25 years, efforts to conserve British butterflies have concentrated on local processes. Researchers have identified the habitat requirements of many species, and used this information to make recommendations for their conservation (this volume). Conservation agencies have then attempted to maintain or re-create these conditions on reserves, in some cases with great success (Thomas, 1991; Warren, 1991). However, at a national scale many species have continued to decline. Agricultural and forestry practices have changed so rapidly and so widely that many species no longer find suitable habitats in most of their former British range: conservation organizations have been unable to protect and maintain more than a scattering of local populations in small reserves. Unfortunately, rare species often have such subtle habitat requirements that many populations have been lost even from reserves and from other fragments of ‘semi-natural’ vegetation as a result of apparently minor habitat changes (Thomas, 1991; Warren, 1993a,b). Good management can reduce the rate of local extinction, sometimes to a very low level, but extinctions cannot be stopped completely. If reserves are completely isolated from one another, population after population will be lost with no opportunity for recolonization. In the long term, the persistence of rare species will depend on the rate of recolonization as well as on the rate of local extinction.
... Many butterfly species are highly mobile and form open populations, with wide-ranging females laying eggs in a number of areas; this group includes the migrant butterflies such as Red Admiral, Painted Lady and Clouded Yellow. However, about three quarters of our butterfly species occupy closed populations (Annex 2), where local birth and death processes are the major determinants of local abundance (Thomas 1995). Sometimes these populations are very small and isolated from other colonies of the same species, but more commonly these populations are connected to each other and dispersal is now recognised as one of the key elements in the maintenance of butterfly populations (Morris et al 1994). ...
... A further refinement of this method is to predict the probability of an occupied habitat patch being colonised over a set period by a particular butterfly based on patch size and the distance from the nearest population patch (Thomas 1995). This can be done by first surveying all the local populations and unoccupied habitat within the area and then measuring the distance from the nearest local population and calculating the probability based on a graph of patch size/distance from the nearest populated patch for each species. ...
... Opportunities for species introduction should be encouraged where possible (Highways Agency 2001) but only for butterflies previously resident in the area, for which the BAP includes reintroduction proposals and for which re-introduction is mentioned in the key actions in the relevant Regional Action Plan published by Butterfly Conservation (Box 2). Re-introductions should then only be attempted if the area available is about 5 times larger than the minimum viable population area and a metapopulation can be established (Thomas 1995). If these criteria are met, then donor sites should be identified and, as lead partner, Butterfly Conservation should be consulted at an early stage to discuss the suitability of the site and advise on procedures. ...
... The term "plagioclimax" can be applied to a vegetation community in which natural succession is halted by continuous management such as cutting, grazing, or fire (Thomas 1995a). Most plagioclimax vegetation consists of a mosaic of microhabitats and microclimates which is essential to butterflies and other insects which are adapted to the early successional environment. ...
... Some butterflies may require different host plants, habitats, or microhabitats in different years or different seasons. The best breeding habitat in a wet year may be different from the best breeding habitat in a dry year, so long-term conservation of these species requires larger areas which incorporate both habitat types (Thomas 1995a). ...
... Habitat patches can then be re-colonized from these refuges, and the creation of habitat "stepping stones" can prevent colonies from becoming isolated. The probability of recolonization of a restored area, within a given time period, is a function of the distance of the restored area from existing populations and the size of each potential source population (Thomas 1995a). It is possible to model this probability, but the accuracy of such a model depends upon knowing vital population parameters, and they are often unknown. ...
... Therefore, local extinctions may occur for stochastic reasons, but in the long run all local populations go extinct deter-ministically. Regional extinction is prevented by new habitat being created to compensate the habitat that has been lost, allowing the species to persist in a given landscape via habitat tracking (Thomas 1994(Thomas , 1995. Well-documented examples of habitat tracking in butterflies include Melitaea athalia (Nymphalidae) (Warren 1991) and Plebejus argus (Lycaenidae) (Thomas and Harrison 1992). ...
... Local populations inhabiting these patches have a distinct risk of extinction, either for stochastic or deterministic reasons (through succession of the transient habitats). This situation is different from other metapopulations of E. aurinia earlier studied by Warren (1994) and Lewis and Hurford (1997), which inhabit habitat patch networks that can be considered as static in relation to the life-times of the populations (see Thomas 1995, Hanski 1999b. The situation we have described here is relatively common in many endangered butterfly species, which in Europe are largely confined to man-made habitats (Thomas 1993). ...
... The meadows can be seen as static as they have earlier been kept open for agricultural reasons (natural pastures for cattle and a source of cattle fodder). Such habitats are known as plagioclimax habitats (Thomas 1995), in which natural succession is prevented. With the cessation of traditional agricultural practices in modern times, natural ECOGRAPHY 25:2 (2002) succession now threatens the habitat of many species of butterfly (Warren 1993). ...
The marsh fritillary butterfly Euphydryas aurinia is an endangered species in most of northern Europe. We describe the metapopulation structure of E. aurinia in Finland, where the species has declined drastically in the past decades. We found two types of habitat patches suitable for the species: semi-permanent meadows and transient clearcuts in the forest. Patch area was the most significant variable predicting the occurrence of E. aurinia in a habitat patch. The species tended to be found in young rather than old clearcuts, apparently because the vegetation became too high in the latter. We used the incidence function model to simulate the metapopulation dynamics of E. aurinia in its dynamic landscape and discovered that the continued presence of the semi-permanent meadows is essential for the survival of the species in the study area in southeast Finland.
... Alternatively, presence of adults in a patch may not necessarily indicate a sustainable population. Highly mobile organisms such as moths and butterflies may visit patches without using them as breeding habitat (Pollard & Yates 1993;Thomas 1995). It should also be noted that unmated Notoreas females oviposit (B. ...
... Some isolated patches were also inhabited, but without knowledge of adult dispersal it is impossible to determine whether these populations were closed and self-sustaining, or part of ametapopulation. Metapopulation theory suggests that isolated patches that are inhabited are not likely to be re-colonised following a local extinction event (Hanski & Thomas 1994;Thomas 1995). However, some species may disperse long distances when faced with dire consequences such as starvation (Schöps 1998) so their dispersal ability differs from dispersal tendency. ...
... (1) Habitat patches should be managed if they are inhabited (especially if large) or within 200 m of an occupied patch. Conserving large amounts of connected patches is recommended since larger patches often "seed" networks of smaller patches (Thomas 1995). Also, large populations in large, high quality habitat are much less likely to become extinct from natural events such as drought than small populations in small patches. ...
Concern over a decline in habitat of an unnamed, endemic species of Notoreas (Geometridae) moth from the Taranaki coast stimulated this study on its distribution and conservation requirements. The caterpillars mine leaves of Pimelea (cf.) urvilleana, a prostrate shrub that can be found among other pioneer plants on coastal cliffs. Forty‐seven patches of habitat were located along 50 km of coastal cliffs adjacent to farmland. Patches were clumped in distribution, and ¾> of the patches were “small”, containing fewer than 15 host plants. Moths were detected in half the patches. Occupied patches were usually large (>25 plants), or if small, were usually within 200 m of another occupied patch. Recommendations for habitat management include weed control and reduction in damage from humans and stock. Ongoing advocacy with land owners and the community is important.
... As a significant portion of the green space, private gardens serve as the food source and refuge for animals (Muratet & Fontaine 2015) [31] . As changes in vegetation have a significant impact on butterfly populations since most butterfly larvae have deep relationships with host plants and adults, require a certain range of nectar plants ( Thomas, 1995) [47] . Globally there are about 18000 species of butterflies present and among these. ...
... As a significant portion of the green space, private gardens serve as the food source and refuge for animals (Muratet & Fontaine 2015) [31] . As changes in vegetation have a significant impact on butterfly populations since most butterfly larvae have deep relationships with host plants and adults, require a certain range of nectar plants ( Thomas, 1995) [47] . Globally there are about 18000 species of butterflies present and among these. ...
The diversity of butterflies (Lepidoptera) with their related host and nectar plants were recorded from the Egra block in Purba Medinipur district of West Bengal. The duration of the work was from (9 months) during the lock down period. A total number 80 species of butterflies were found from this block which belongs to 59 genera from five families. Among these, the highest number of species i.e., 26 (32.91%) was recorded from Lycaenidae family in which 11 are legally protected Under the Wildlife (Protection) Act of 1972. From the analysis we found that, the Shannon-Wiener index was 3.272, Shannon Evenness (J') value was 0.751 and the Simpson's index has a value 0.944. During the study, a total number of 54 host plants from 27 families and 77 nectar plants of 29 families were recorded. However, the major threat here is the application of harmful pesticides and herbicides beyond safe limit associated with agriculture, which not only affected the butterfly diversity, but also destroying overall ecosystem of this rural areas.
... arethusa sont davantage affectées par les processus stochastiques qui en résultent, d'autant plus si les populations sont de petites tailles et isolées. Dans un contexte de mise en oeuvre de la politique dite « Trame verte et bleue » et parce que le fonctionnement métapopulationnel doit être recherché pour assurer une conservation durable de la plupart des papillons de jour (Thomas & Jones 1993 ;Hanski & Thomas 1994 ;Thomas 1995 ;Schtickzelle et al. 2005), la connaissance des capacités de déplacements d'A. arethusa est importante pour établir les stratégies de conservation. ...
... Les rares plantes butinées par A. arethusa y sont associées : Eryngium campestre, Scabiosa columbaria, Origanum vulgare L., Centaurea jacea L. STERF_4033 (04) STERF_5127 (05) STERF_34058 (34) STERF_34118 (34) STERF_27465 (27) À l'image du camp militaire de Sissonne (Aisne) où prospère sur près de 5000 hectares de pelouses et prairies sèches l'essentiel des effectifs régionaux d'A. arethusa, la conservation durable des populations se développant sur des espaces de petites tailles et fragmentés ne peut s'envisager sans la restauration d'un fonctionnement métapopulationnel dans un réseau fonctionnel de sites (Thomas & Jones 1993 ;Hanski & Thomas 1994 ;Thomas 1995 ;Schtickzelle et al. 2005). ...
Le Mercure Arethusana arethusa (Denis & Schiffermüller, 1775) est un papillon qui, actuellement, n’est pas considéré comme menacé au sein des Listes rouges de France et d’Europe mais dont la distribution apparaît cependant en déclin. Le Conservatoire d’Espaces naturels des Hauts-de-France préserve deux des trois stations restantes en région. Sur la base de captures-marquages-recaptures et d’observations réalisées entre 2013 et 2019 sur les deux dernières populations du département de la Somme, nous avons étudié les paramètres démographiques, la mobilité des individus et leur utilisation des habitats. Les effectifs des populations ont été estimés avec une certaine précision puisque les marges d’erreur des estimations pour un niveau de confiance de 95 % étaient comprises entre 13 et 19 % selon les sites et les années. Des variations importantes d’effectifs, de plus de 50 %, ont été relevées entre certaines années et reflètent les tendances observées au niveau national dans le cadre des suivis des communautés de papillons de jours. Durant les trois années de suivis, la taille des populations est la plus élevée entre le 20 août et le 30 août. Le pic de vol des femelles intervient entre trois et six jours après celui des mâles et dure moins longtemps. Selon les sites et les années, la durée de vie moyenne est comprise entre 5,75 et 12 jours. Le sexe ratio mâles/femelles est de 1,18 en 2018 et de 1,28 en 2019. Si le contexte des sites étudiés (faible superficie, isolement) n’a pas permis d’étudier les capacités de dispersion d’A. arethusa, nous avons constaté que l’espèce se déplace peu dans ce contexte. La distance moyenne de déplacement est de 86,46 ± 6,34 m après au moins trois recaptures (n = 81). La distance maximale relevée entre deux captures est de 333 m. Les pelouses qui présentent une hauteur de végétation rase (6,57 ± 2,39 cm), avec des affleurements crayeux (8,21 ± 7,35 % par m²) et un recouvrement riche en Festuca ovina Gr. (22,6 ± 9,54 % par m²), constituent les habitats larvaires. Si ces milieux constituent également les habitats préférentiels des adultes, les pelouses plus fermées et jeunes ourlets calcicoles apparaissent complémentaires car elles offrent des ressources nectarifères qui sont faibles sur les pelouses les plus rases en période de vol du papillon. Nos résultats conduisent à faire émerger une question de conservation : comment faire coexister sur des petits espaces des dynamiques spatiales et temporelles de la végétation permettant d’assurer une disponibilité en ressources et en habitats nécessaires à l’accomplissement du cycle de vie d’A. arethusa ? Dans des paysages dominés par les grandes cultures, nous soulignons le rôle fonctionnel des prairies, jachères et bandes enherbées pour renforcer les populations en place et reconnecter les espaces fragmentés.
... Forest degradation due to development and construction activities in city areas and destroy forest habitat leads to biodiversity worldwide (Houlihan et al., 2013;Fiedller and Schulze, 2004) [35,36] . They quickly responds to environment changes because of their short life cycle, high mobility and specific habitat preference (Dennis, 1972;Thomas, 1995) [37,38] . They are also known to susceptible towards changes among habitat i.e. grassland, silviculture, deserted land, clear cutting of forest and trees and land conversion (Nakamura 2011; Lee and Kwon, 2012) [39,40] . ...
... Forest degradation due to development and construction activities in city areas and destroy forest habitat leads to biodiversity worldwide (Houlihan et al., 2013;Fiedller and Schulze, 2004) [35,36] . They quickly responds to environment changes because of their short life cycle, high mobility and specific habitat preference (Dennis, 1972;Thomas, 1995) [37,38] . They are also known to susceptible towards changes among habitat i.e. grassland, silviculture, deserted land, clear cutting of forest and trees and land conversion (Nakamura 2011; Lee and Kwon, 2012) [39,40] . ...
Lepidoptera is beneficial insects group as a pollinators, silk producers and bio-indicator towards environmental changes and recognizable as an aesthetic value. It's diversity and abundance changes as environment changes. Now a day's people are using organic farming and poly culture corps it increases butterfly diversity and density. In present time global warming and urbanization are two main key factors responsible for declining biodiversity worldwide.
... Many populations of Lepidoptera species exist in a network of suitable habitats in a metapopulation structure (Hanski & Gilpin, 1991) and their survival may depend on the protection of these metapopulations (e.g. Thomas & Jones, 1993; Hanski, 1994; Thomas, 1995; Saccheri et al., 1998; Wahlberg, Klemetti & Hanski 2002); local populations within colonisation range may be regarded as belonging to a single metapopulation (e.g. Thomas & Harrison, 1992). ...
... This may be true of the other subspecies of L. nickerlii: gueneei in northern Britain where new colonies are occasionally founded (Burkmar & Jones, 2008 ), demuthi on the saltmarshes of southeast England and knilli on the cliffs of south-west Ireland. Metapopulations are characterised by colonisations and extinctions (Thomas, 1995) and lepidopteran species normally existing in metapopulations may not survive in isolation (Mene´ndezMene´ndez & Thomas, 2000). Sandhill Rustics at Loe Bar are completely isolated from all other known sites and may therefore not be able to survive in the long term. ...
The colony of the nocturnal moth Luperina nickerlii leechi Goater was studied between 1995 and 2009 on Loe Bar in Cornwall, where it persists as an isolated population separated from the nearest populations by over 300km. This study investigates the population size using transect studies, linked to detailed mapping of individual moths and the larval foodplant Sand Couch-grass Elytrigia juncea. There has been remarkable persistence in this single, small, isolated population but long-term trends indicate that the population may be gradually declining. Seventy percent of the recorded moths are female and males may find it easy to find females in the relatively small area of larval foodplant, which at its most extensive covers less than 20,000 m 2 . Residence time at around 3.79 days allows time for females to mate and lay eggs. Restricted mobility ensures that moths do not lose touch with their habitat. The earlier the emergence the longer the flight period, so that factors which affect early emergence are probably beneficial.
... 2001). However, as the most mobile British butterflies do not operate as metapopulations ( Thomas 1995), it seems unlikely that this can be the only explanation for the positive density-distribution relationship. Negative deviation from the underlying density-distribution pattern could also be the result of mobile species being more likely to be recorded as vagrants, and therefore being recorded over a wider area (Gaston 1994). ...
... This requires that species exist as a series of discrete local populations within which many or most individuals are born and die, with the populations linked by some dispersal of individuals, and local populations exhibiting extinction and recolonization (Hanski 1991). Crudely, British butterfly species that form 'closed' populations ( Thomas 1984) are those most likely to exhibit metapopulation dynamics ( Thomas 1995); whereas species with 'open' populations certainly do not, at the landscape scale. ...
The interspecific density–distribution relationship is a general and robust pattern that has been described as a rule in community ecology. Many theoretically plausible causes of the relationship have been described, but it is still disputed which factor(s) are most important.
Using data on the densities and distributions of butterflies and their host plants collected in a 35‐km ² area of north Wales, and data on butterfly mobility, niche breadth, habitat breadth and distance from range margins, we examined five of the principal explanatory mechanisms.
We found that several variables were significantly correlated with density or distribution. Habitat breadth, mobility and distance from range margin had significant positive effects on butterfly distribution. Host‐plant density was significantly positively related to butterfly density; mobility was significantly negatively related to density.
Despite these results, we could not unambiguously demonstrate that one hypothesis (or several interacting hypotheses) generated density–distribution correlations. The most conclusive evidence was that statistical patterns of distribution (aggregation models) underpinned the positive density–distribution relationship seen amongst the more mobile butterflies. The results provided evidence against the metapopulation dynamic explanation, and were equivocal with respect to the contributions of range position, niche breadth and resource availability.
An alternative approach was to explore deviations from the underlying relationship between density and distribution, rather than concentrating on the correlation itself. This approach was much more successful: we demonstrated that species that occurred at high densities relative to their distributions used aggregated resources and were relatively sedentary; whereas those that occurred at low densities relative to their distributions used less aggregated resources, and were more mobile. Mobile species had less aggregated distributions than did relatively sedentary species.
Given that the interspecific density–distribution pattern appears to be almost ubiquitous and that the proposed explanations are not mutually exclusive, faster progress may be made by examining deviations from the pattern than from further analysis of the pattern itself.
... Vegetation changes have a significant impact on butterfly communities, as the larvae of most butterfly species are closely associated with specific host plants, while adults require a range of nectar plants (Thomas 1995). Butterflies frequently rely on floral resources in urban environments, and the diversity of butterflies is often correlated with the number of flowers present (Shwartz et al. 2014). ...
Ecosystems depend on biodiversity; therefore, protecting biodiversity is beneficial for the development of ecosystems. Butterflies are indicator species that respond quickly to environmental changes and reflect environmental conditions. Butterfly diversity is a crucial evaluation indicator of habitat quality in green spaces. We used CiteSpace and Bibliometrix to conduct a bibliometric analysis of research relating to butterfly diversity in green spaces. Based on 538 papers published from 2002–2022, we systematically reviewed the status, frontiers, and hotspots for research on butterfly diversity in green spaces. Our results showed that: (1) Research on butterfly diversity in green spaces has consistently demonstrated an upward trend between 2002–2022. Studies on this subject have garnered attention from researchers worldwide, with notable interest and contributions from scholars in the United States. (2) Early studies focused on butterfly habitat preferences and extinction concerns, and later articles appeared on the influence of external environmental factors (land use, climate change, plants, etc.). (3) Three main research topics received much attention between 2002 and 2022: biodiversity conservation, butterfly habitats, and the relationship between butterfly diversity and its influencing factors. (4) The relationship between green spaces and butterfly diversity (landscape features, vegetation features, and human activities) was discussed; these factors on butterfly communities should be considered in the planning and constructing of future green spaces. (5) Two significant future directions have been identified: more research on the impact of external factors and a need for more technical integration with the big data field. Future research on butterfly diversity in green spaces should adopt a more multi-scale, multi-disciplinary approach and aim to enhance the practicality and guidance of research findings.
... The idea of spatially structured population, namely metapopulation, patchy population, mainland-island system, or source-sink systems, has become a very powerful concept in ecology, raising interest in research areas like dispersal ecology (Hanski, 2012;Lambin et al., 2012; or population genetics (Haig, 1998;Harrison & Hastings, 1996;Hastings & Harrison, 1994;Manel et al., 2003;Montgelard et al., 2014). The concept also had a strong impact on the development of conservation concepts (Akçakaya et al., 2007;Hanski & Simberloff, 1997;Olivieri et al., 2016;Thomas, 1995). ...
The idea that populations are spatially structured has become a very powerful concept in ecology, raising interest in many research areas. However, despite dispersal being a core component of the concept, it typically does not consider the movement behavior underlying any dispersal. Using individual‐based simulations in continuous space, we explored the emergence of a spatially structured population in landscapes with spatially heterogeneous resource distribution and with organisms following simple area‐concentrated search (ACS); individuals do not, however, perceive or respond to any habitat attributes per se but only to their foraging success. We investigated the effects of different resource clustering pattern in landscapes (single large cluster vs. many small clusters) and different resource density on the spatial structure of populations and movement between resource clusters of individuals. As results, we found that foraging success increased with increasing resource density and decreasing number of resource clusters. In a wide parameter space, the system exhibited attributes of a spatially structured populations with individuals concentrated in areas of high resource density, searching within areas of resources, and “dispersing” in straight line between resource patches. “Emigration” was more likely from patches that were small or of low quality (low resource density), but we observed an interaction effect between these two parameters. With the ACS implemented, individuals tended to move deeper into a resource cluster in scenarios with moderate resource density than in scenarios with high resource density. “Looping” from patches was more likely if patches were large and of high quality. Our simulations demonstrate that spatial structure in populations may emerge if critical resources are heterogeneously distributed and if individuals follow simple movement rules (such as ACS). Neither the perception of habitat nor an explicit decision to emigrate from a patch on the side of acting individuals is necessary for the emergence of such spatial structure. We investigate the emergence of a spatially structured population in landscapes with spatially heterogeneous resource distribution and with organisms following simple area‐concentrated search (ACS) by using individual‐based simulations in continuous space. We found that neither the perception of habitat nor an explicit decision to emigrate from a patch on the side of acting individuals are necessary for the emergence of spatial structure.
... The metapopulation structure adopted by many lepidopteran species is particularly vulnerable to these effects, whereby if the effects of fragmentation reduce movement between patches, persistence of the entire metapopulation may be at risk. It has been suggested that a minimum of 20 connected patches is necessary to ensure metapopulation survival (Thomas, 1995). ...
p>Populations of P. bellargus were examined to assess whether the genetic structuring reflects a recent colonisation even in the UK, as is inferred by the historical data for the species. To achieve this, the AT-rich mitochrondrial control region was sequenced from individuals throughout the UK range and southern France. Genetic diversity was found to be much lower in the UK, with only three closely related haplotypes among fifty UK specimens, whereas six were identified from eight butterflies from France. The predominant UK haplotype, which was at fixation in most UK populations, was almost identical to one from France, suggesting that the UK population has a French origin. The only reasonable explanation for the observed patterns of MtDNA diversity is a recent and rapid colonisation even from France via one or a few female butterflies.
Five microsatellite DNA markers were isolated and used to examine the relationship between spatial distribution and population genetic structure among a subset of UK populations of P. bellargus . The butterfly is at its northern range limit in the UK, where it exists in a highly fragmented metapopulation structure on isolated pockets of calcareous grassland. These populations were affected by a severe population bottleneck in the late 1970's, when a drought caused large numbers of the host plant ( Hippocrepis comosa ) to wilt. Mantel tests indicated a significant effect of isolation by distance among the UK populations, a relationship that broke down at greater geographic scales (>37.5km), probably because of large areas of unsuitable habitat presenting barriers to gene flow.</p
... The metapopulation concept has been a very powerful one in ecology, raising interest in research areas like dispersal ecology [1][2][3] or population genetics [4][5][6][7][8]. The concept also had a strong impact on the development of conservation concepts [9][10][11][12]. Yet there are also issues about its generality as the occurrence of metapopulations may be restricted to a rather small region in parameter space with many spatially structured populations basically behaving like patchy populations, mainland-island systems, non-equilibrium metapopulations or panmictic populations [13,14]. ...
Background: The idea that populations are spatially structured has become a very powerful concept in ecology, raising interest in many research areas. However, despite dispersal being a core component of the concept, it typically does not consider the movement behavior underlying any dispersal.
Methods: Using individual-based simulations in continuous space, we investigate the emergence of a spatially structured population in landscapes with spatially heterogeneous resource distribution and with organisms following a simple area-concentrated search (ACS).
Results: We found that foraging success increased with increasing resource density and decreasing number of resource clusters. In a wide parameter space, the system exhibited attributes of a spatially structured populations with individuals concentrated in areas of high resource density, searching within areas of resources, and 'dispersing' in straight line between resource patches. 'Emigration' was more likely from patches that were small or of low quality (low resource density). 'Looping' from patches was more likely if patches were large and of high quality. With the ACS implemented, individuals tended to move deeper into a resource cluster in scenarios with moderate resource density than in scenarios with high resource density because of more space between resource items.
Conclusion: Our simulations demonstrate that spatial structure in populations may emerge if critical resources are heterogeneously distributed and if individuals follow simple movement rules (such as ACS). Neither the perception of habitat nor an explicit decision to emigrate on the side of acting individuals are necessary for the emergence of spatial structure. Mechanistic models like ours may help to close the gap between movement ecology and spatial ecology theory.
... High butterfly species richness in non-natural places highlights the importance of urban and semi-urban areas for the conservation of this group (Magle et al. 2012) and has led to an increased interest in documenting and assessing how butterflies use of these areas (Lang et al. 2019). Species of Lepidoptera show differences in habitat preference, dispersal abilities, and tolerance to perturbation (Thomas 1995;MacGregor-Fors et al. 2015), which is why the composition of butterfly assemblages can inform about the conservation status of ecosystems (Brown 1991;de la Maza and Soberón 1998;Checa 2013). For these reasons, research that helps to understand the role of urban and semi-urban areas as refugia for butterfly diversity is of critical importance. ...
Urbanization rates are increasing worldwide; therefore, urban and semi-urban ecosystems are the focus of various studies that explore their importance for biodiversity conservation. In the order Lepidoptera high species diversity has been observed in areas with distinct levels of disturbance. In Ecuador, most efforts to study the diversity of butterflies have been concentrated in protected natural areas, whereas studies in semi-urban or urban areas are limited. In this study, we measured the diversity of diurnal Lepidoptera in two semi-urban areas, in southern Ecuador. We visited these areas during the dry season, in the hours of peak butterfly activity, and recorded the species and abundances of each. We estimated relative abundances, evenness, and beta diversity to characterize butterfly assemblages. We found high abundance and richness of Lepidoptera species and low similarities between the two semi-urban areas (Jaccard index = 0.21). Highest species richness was observed in the most heterogeneous area in terms of vegetation composition, owing to the type of management that it receives. Four species represented 50% of the total abundance observed in both sites, and various singletons were registered. This pattern of dominance is characteristic of disturbed areas, where generalist species adapt easily to anthropic environments. However, we also found relatively high richness and abundance of the members of the tribe Ithomiini, which are mostly present in primary forests. Our findings highlight the importance of semi-urban areas for conservation of butterfly diversity and the crucial role of proper management of anthropic areas to preserve biodiversity in this changing world.
... Larval stages of monophagous and oligophagous butterflies exhibit a high host plant specificity (Klaiber et al., 2017), while adults often show a distinct preference for assorted nectar plants and generally prefer flower rich landscapes (Schweizerischer Bund für Naturschutz, 1987). Especially less mobile butterfly species depend on a network of suitable habitats to maintain resilient metapopulations (Thomas, 1995). Due to these complex requirements, butterflies respond rapidly to environmental changes, being representative for wider trends in insect abundance (Thomas, 2005). ...
Habitat fragmentation, as a result of habitat loss and degradation, is widely considered to be a major threat to biodiversity. Our study focused on the distribution, diversity and abundance of butterflies on 22 isolated plots, mainly consisting of wet grassland. The plots were surrounded by deciduous mixed forests and located in an agglomeration area close to Lake Zurich, Switzerland. In addition to vegetation parameters, we assessed structural connectivity, adapted to least cost distances, using digital surface and terrain models. The resulting mixed-effects models revealed on plot level that (1) Molinia meadows had a significantly positive effect on rarefied Simpson butterfly diversity, (2) structural connectivity had a highly significant negative impact on rarefied Simpson butterfly diversity, whereas (3) plot size showed a significant positive impact, and (4) higher butterfly abundance was strongly related to blossom density. Across plot level, Molinia meadows had a higher rarefied butterfly species richness and rarefied Simpson butterfly diversity than any of the other habitat types evaluated. Among the endangered target species, the preferences of the Alcon Blue Phengaris alcon alcon were consistent with (1) to (3), while those of the Marsh Fritillary's E. aurinia aurinia were not. (2) is discussed with regards to the predominant influence of habitat type, vegetation and plot size, relativizing the effect of structural con-nectivity on butterfly communities in presumably resilient metapopulations. Ongoing targeted maintenance measures in the study area provide a promising basis for the sustainable conservation of local butterfly communities in isolated wet grassland plots.
... In this study we analysed the effect of factors at both the local and landscape scale on butterfly diversity in pine plantation landscapes. Butterflies were chosen because they are easy to identify in surveys and include species with different habitat preferences and dispersal capacities and show therefore different responses to habitat and landscape features (Dennis, 1992;Thomas, 1995). Moreover, a large number of butterfly species are declining at an alarming rate through substantial parts of their European range and conservation measures are urgently needed . ...
While the area of plantation forests continues to increase worldwide, their contribution to theconservation of biodiversity is still controversial. The aim of this thesis is to identify key habitat andlandscape factors that drive butterfly diversity in mosaic landscapes dominated by pine plantations.Butterfly communities were sampled at edges and interiors of five successional stages of pine stands,in firebreaks, riparian forests and in deciduous woodlands varying in fragment size and isolation.Biological and ecological traits of butterflies were related to habitat patch attributes and tolandscape composition and configuration.The results highlighted the critical importance of semi-natural habitats for butterfly conservation inpine plantation mosaics, i.e. deciduous woodlands, firebreaks and edges. Riparian forests wereespecially rich in forest butterfly species, harboring specialized species with both narrow habitat andthermal ranges. Firebreaks had twice as many species as other habitat types and were ofconservation value for several threatened butterfly species. Our results also showed that pine standswere not ‘free of butterflies'. Habitat quality, particularly the presence of host plants, was the mostimportant driver of butterfly community composition. Landscape composition and configuration alsoinfluenced butterfly diversity. Many species used more than one distinct habitat type, suggestingthat resource complementation and supplementation are important mechanisms of butterflydiversity persistence in pine plantation mosaics.
... Many species of insect occupy transient as well as patchy habitats. Here, dispersal is essential if metapopulations are to persist, tracking changes in the spatial distribution of suitable breeding habitats (Warren 1987;Thomas 1991b;Thomas 1995). In such species, persistence is likely to depend on the regular creation (naturally or through active management) of new habitats that are within the 'normal' dispersal range of the species. ...
... Smith et al., 2002). Butterfly communities are greatly affected by changes in vegetation, because most butterfly larvae have strong associations with their host plants and adults require a specific range of nectar plants (Thomas, 1995;Honda & Kato, 2005;Lee et al., 2015). In addition, the taxonomy and life histories of most Korean species are already well known and the adults of many species can be reliably identified in the field (Kim & Seo, 2012;Kim et al., 2012;Lee et al., 2015). ...
Military training areas are increasingly recognized as areas of high biodiversity and habitats for many wild organisms, including threatened or endangered species. However, the information on the ecological value of military training areas is limited because it is difficult access these sites. The aim of this study is to evaluate the effect of military activity on butterfly communities. The survey was carried out in a military training area (MTA) at Inje-gun near the demilitarized zone (DMZ), Inje forest (IJF) a secondary forest and Gwangneung forest (GWF) an old growth forest, from April to October 2008 to 2011. IJF and GWF were selected in order to determine the characteristics of a butterfly community differed in a MTA. Butterfly communities differ greatly among sites. Estimated species richness and species diversity were significantly higher in MTA compared to GWF. Grassland species were abundant in MTA and forest interior species in GWF. Species richness and abundance of red listed species, especially grassland species, were greatest in MTA, but absent in GWF. Military activities were beneficial for red listed grassland species because they maintained an open habitat, which is rare elsewhere in current Korea. This study indicates that MTAs are important in terms of conservation and in providing a refuge for red listed grassland species.
... u nehmende Fragmentierung der Kalk mager rasen und die fehlende Nutzung haben einen gravierenden Rückgang vieler Tierarten zur Folge. Dies gilt in besonderer Weise für Tagschmetterlinge und Wid derchen (vgl. BOURN & THOMAS 2002). Die Arten beider Tiergruppen sind durch eine mehr oder weniger stark ausgeprägte Metapopulationsstruktur gekennzeichnet (C. D. THOMAS 1995 und somit in besonderer Weise von einer Ver inselung der Habitate betroffen. Darüber hinaus ist ein hoher Anteil der Taxa auf frühe Sukzessions stadien angewiesen, die aufgrund fehlender Störungen in den Magerrasen zunehmend verloren gehen (J. A. THOMAS 1993, J. A. THOMAS & MORRIS 1994, BOURN & THOMAS 2002. ...
... However, the extent and spatial scale of predicted fragmentation effects depend not only on structural connectivity, but also on the dispersal ability of the study species (Hanski 1999, Driscoll andWeir 2005). Species with low dispersal ability are more severely affected by fragmentation, and are the first to lose the ability to recolonize as habitat fragments become smaller and more isolated (Thomas 1995). Gall wasps, however, include highly dispersing species, and can spread a long way very quickly in air currents, even across unfavourable habitats (Hough 1951, Stone and Sunnucks 1993, Nieves-Aldrey 1995, Schö nrogge et al. 2011. ...
We explore the impact of habitat fragmentation on interactions between keystone resources of forest trees—oaks, genus Quercus (Fagaceae)—and an associated radiation of specialist cynipid gall wasps. Habitat fragmentation is predicted to have bottom-up impacts on cynipid communities through impacts on host plant quality (plant vigor hypothesis). We explored the bottom-up impacts on cynipid communities of habitat fragment size, fragment edge effects and presence of isolated oaks. We quantified temporal and spatial variation of leaves produced in the canopy to quantify plant vigor, and surveyed cynipid gall species abundance and richness over three years using 15 permanent forest patches and 25 isolated oaks in a fragmented oak woodland landscape in central Mexico. Cynipid gall abundance and species richness were higher in isolated oaks and small woodland fragments than in larger ones. Cynipid abundance and species richness were also higher along fragment edges in comparison with fragment interiors. This contrasts with patterns observed in other taxa. In addition, host plant quality was higher in isolated trees, in smaller fragments and along fragment edges. We therefore hypothesize that observed patterns in cynipid abundance and species richness are driven by changes in host plant quality due to forest fragmentation. Our data represent a baseline for longer-term monitoring of fragmentation effects at a landscape scale. Further work is required to explore alternative potential explanations for observed patterns, including the estimation of potential top-down impacts of fragmentation mediated by natural enemies.
... Butterflies are also well known both taxonomically and ecologically (Honda and Kato 2005;Kim et al. 2011). Butterfly communities are greatly affected by vegetation changes because most butterfly larvae have strong associations with host plants, and adults require a specific range of nectar plants (Thomas 1995;Honda and Kato 2005). Butterflies are known to respond sensitively to the effects of urbanization (Clark et al. 2007; Lee and Kwon 2012;Lizée et al. 2012). ...
Urbanization is one of the leading causes of habitat loss, habitat degradation, and fragmentation. Urban development negatively affects biodiversity. We clarified changes in butterfly communities due to urbanization in urban green areas.
In total, 59 species and 1,465 individuals of butterflies were observed in the four urban green areas – Namsan Park (NS), Ewha Womans University (EW), Bukseoul Dream Forest (BD), and Hongneung Forest (HF) – and a natural forest, Gwangneung Forest (GF). The categories of land use around the study sites were determined based on GIS data. Species richness and density of niche breadth and habitat type in the four urban green areas differed mostly from those in GF. Estimated species richness and species diversity (H’) in the four urban green areas were significantly lower than those in GF. Species richness and density of forest interior species and specialist species were positively correlated with paddy, field, and forest, whereas those of forest interior species and specialists were negatively correlated with urban area and road. Species composition and community structure of butterflies in the four urban were differed from those in GF.
These results suggest that decreases in paddy, field, and forest associated with the increased urban area and road negatively influenced species composition and changed butterfly communities.
... 국내에서 개벌의 영향에 관한 연구는 개벌 이후 계류수질의 변화 (Park, 2002), 소나무림 개벌 (Rainio and Niemelä, 2003;Maleque et al., 2009). 그 중 나비는 조사가 쉽고 다양성이 높으며 생활사가 잘 알려져 있으 며 (Pollard and Yates, 1993), 짧은 세대기간, 좋은 이동능력, 기 주 선호성 때문에 환경변화에 민감하게 반응한다 (Thomas, 1995;Kwon et al., 2010;Lee and Kwon, 2012;Lee et al., 2013). 나비 는 곤충 중에서 비교적 대형종으로 야외에서 직접관찰만으로 대부분의 종들이 동정 가능하여 선조사법으로 정량적인 조사 가 가능하다 (Pollard and Yates, 1993). ...
This study was carried out to clarify the change of butterfly community after clear cutting. Butterfly survey was conducted in clear cutting area, forest road, and forest using line transect method from May to November in 2011. A total of 32 species and 398 individuals of butterflies were observed. Abundance of food niche breadth and habitat type was significantly higher in clear cutting area than in forest. Estimated species richness and species diversity were significantly higher in clear cutting area than in forest. In clear cutting area, Leptidea amurensis and Argynnis niobe, vulnerable species, were abundant. This result suggests that grasslands formed by clear cutting play an important role to increase butterfly diversity in forest ecosystem.
... Butterflies have been frequently used as bio-indicators due to their high species diversity, in addition to their well-known taxonomy and life cycle (Pollard & Yates 1993;Honda & Kato 2005). Furthermore, butterflies rapidly respond to environment changes because of their short generation, good mobility and specific habitat preferences (Dennis 1992;Thomas 1995). Butterfly communities are greatly affected by vegetation change because most butterfly larvae have strong associations with host-plants, and adults also need a specific range of nectar plants (Honda & Kato 2005). ...
This study was carried out to clarify the response of butterfly communities on forest degradation in the Gwangneung Forest, Korea. We monitored butterfly communities with varying degrees of human activities by conducting a line transect twice a month in 2011. A total of 70 species and 4676 individuals of butterflies were observed in four sites: natural forest (NR), two plantation forests, and the Korean National Arboretum (AR). The result on niche breadth, habitat breadth and habitat type of butterfly was not consistent with our predictions. Species richness of habitat type was only significantly different between NF and AR. Species diversity was significantly different among sites. Butterfly diversity associated with landscape patterns based on aerial photographs supported a mosaic concept. A forest management plan to conserve butterfly diversity in forests is necessary to maintain various habitats and to ensure that grasslands are protected.
... Examples are many butterfly-species (e.g. Thomas, 1995;Thomas and Hanski, 1997), grasshoppers (e.g. Appelt and Poethke, 1997;Carlsson and Kindvall, 2001) and amphibians like the European tree frog (Hyla arborea) (Anderson et al., 2004;Pellet, 2005). ...
In the state of Baden-Wuerttemberg, Germany, an approach has been developed to identify areas of high priority for the conservation of fauna target species. It produces a spatial refinement of the governmental Target Species Concept leading to an assignment of ‘conservation responsibilities’ to the state's 1112 municipalities. The results are integrated in the ‘Information System Target Species Concept Baden-Wuerttemberg’, a web-based planning tool designed for the environmental administration and consultants. The developed approach consists of the following steps: (1) grouping of fauna target species into 25 habitat groups, (2) deriving potential habitats for these groups through knowledge-based habitat models, (3) delineating Potential Habitat Networks, (4) selecting priority areas using the indicators ‘patch-size’ and ‘patch-connectivity’, and (5) assigning ‘conservation responsibilities’ to those municipalities covering priority areas or parts of them. For the implementation of the indicator ‘patch-connectivity’ a new GIS-based method has been developed to delineate ‘Potential Habitat Networks’. The approach was validated for several habitat-types using zoological field data. The analyses covered (1) the validity of the habitat models, (2) the suitability of the indicators to select priority areas, and (3) the spatial correspondence of municipalities with ‘conservation responsibilities’ and zoological ‘biodiversity hotspots’. The results show an overall high plausibility which supports the consistency of the developed approach. Focussing conservation strategies on the derived priorities is considered a promising approach for a more efficient and standardized protection of biodiversity.
... Mardon skippers use Roemer's fescue (Festuca roemeri) and red fescue (Festuca rubra -Cascades populations) as larval host plants (The Xerces Society 2002b). Research into the silver spotted skipper (Hesperia comma) in Britain (Thomas 1995) shows that although the foodplant, sheep's fescue (Festuca ovina) is common, females lay eggs only on plants that are adjacent to bare ground. Plants in crowded conditions are ignored, perhaps due to physical obstruction or unfavorable microclimate. ...
... invaders and some generalists) are known to disperse on the scale of hundreds or thousands of km. Most butter¯y species appear to be year-round residents within their habitat patches, usually dispersing up to 1 km or 2 or 10 (Scott, 1975;Thomas, 1989;Shreeve, 1995;Thomas, 1995). The prairie-specialist butter¯ies typically remain inside their particular prairie remnants, with relatively little dispersal apparently occurring among these patches except for the most closely situated ones (Opler, 1981;Opler and Krizek, 1984;Moat and McPhillips, 1993;A. ...
Transect surveys of adult butterflies were conducted along fixed routes at 27 study sites grouped into three subregions of tallgrass prairie and one subregion of pine-oak barrens in the midwestern USA. Within subregion, each site was visited the same number of times over 5–7 years on similar dates with similar weather. For each site, five indices of species richness and/or abundance were calculated both for total butterflies and for specialist species primarily restricted to native herbaceous vegetation. These indices were then analysed as to how much they agreed or conflicted in site ranking and how site rankings based on total butterflies compared to those based on specialists. Variation in site ranking by different indices was relatively low. Mean site rank by specialist indices covaried significantly with mean site rank by indices for total butterflies. Numerous studies have shown that on a regional scale, areas of higher richness for all species in a taxonomic group are different habitat types (based on amount of canopy or degree of degradation) from “hotspots” for that taxon's subset of species of conservation concern (endemics or specialists). But in this study, within a habitat type, site rankings based on total butterflies significantly tended to agree with site rankings based on specialist butterflies. This suggests that site prioritization and management favouring specialist butterflies would also favour the overall butterfly fauna possible in the same habitat.
... A maior riqueza em ambientes de capoeira e matriz pode ser explicada em grande parte pela existência nesses locais de poças d'água, pela sua maior heterogeneidade estrutural e pelo fato desses ambientes poderem constituir estágios intermediários de perturbação (CONNELL 1978, SOUSA 1984, HUSTON 1994, ROSENZWEIG 1995, TOKESHI 1999. Mudanças na composição das assembléias de vários grupos de animais, vertebrados e invertebrados, ao longo da sucessão da vegetação também vêm sendo relatadas em diferentes biomas (RICHARDS 1926, MARGALEF 1977, SOUSA 1984, USHER & JEFFERSON 1991, THOMAS 1995, STEFFAN-DEWENTER & TSCHARNTKE 1997, BALMER & ERHARDT 2000, IMBEAU et al. 2003, NICHOLS & NICHOLS 2003. ...
The objective of this work it was verify the abundance, richness, and the anuran composition in plots of vegetation of different succession stages in a forest and the matrix that surrounds it, of Acre (10º04'S, 67º37'W). The sampling was carried out between August 2005 and April 2006 in twelve plots located in three different sites in the forest. In each site four kinds of environments were chosen: primary forest (wood), secondary forest (capoeira), periphery (matrix) and secondary forest (succession). A total of twenty-seven species distributed in seven families was found. Greater abundance was registered in the plots of matrix two and capoeira three and the least in succession one. The richness was greater in matrix two, with the greater number of exclusive species. The abundance of anurans correlated significantly, with the average circumference at the breast height of the trees of the plots. The richness however correlated only marginally, with this structural feature. The larger richness in plots of capoeira and matrix can be explained partially by the existence of temporary ponds and more structural heterogeneity is able constitute intermediary stages in a gradient of perturbation and this can increase the biodiversity. Thus environments with intermediary levels of disturbance are important for the conservation of the diversity of anuran amphibians.
... Primack 1993, Several studies have shown that species exhibiting metapopulation dynamics tend lo inhabit successional (Bengtsson 1991. Sjogren 1991 or ephemeral (Primack 1993, Thomas 1995 habitats. Since the basidiocarp habitat of B, reliculalus is both successional and ephemeral, we wanted to see if B. rcikiilalus showed similar dynamics. ...
Effects of isolation, habitat size and several microhabitat variables on presence/absence of the monophagous Bolitophagus reticulatus (L.) (Coleoptera. Tenebrionidae) were investigated in 58 forest fragments in an agricultural landscape (15 km2) in south-eastern Norway, All potential habitats of the beetle, dead Fomes fomentarius (L,) Kiekx basidiocarps (n = 587), were collected from trees (n = l85) within the study area. The basidiocarps were dissected and the number of B, reticulatus specimens (larvae, pupae and adults) counted. The material was analysed at four distinguishable spatial scales; basidiocarp-. tree-, tree-group- and forest island level. Different patterns of beetle presence emerged at the different scales, increasing habitat size and decreasing degree of isolation increased the probability of B, reticulatus presence at three (basidiocarp-, tree- and forest island level) and one (tree level) scales, respectively, whilst no such trends were found at the fourth level (tree-group level). Increasing insolation and thereby higher ambient temperatures, indicated by several microhabitat variables, improved the probability of beetle presence amongst the trees. The number of beetle specimens correlated positively with an increase in the habitat size at the tree level.
... Rare insect species often have subtle habitat requirements and have even been lost from reserves as a result of apparently minor habitat changes (Thomas 1995). The large blue butterfly (Maculina arion) larvae is an obligate parasite of red ant (Myrimica sabuleti) colonies. ...
Invertebrates eclipse all other forms of life on Earth, not only in sheer numbers, diversity, and biomass, but also in their importance to functioning ecosystems. Invertebrates perform vital services such as pollination, seed dispersal, and nutrient recycling. Although invertebrates are vitally important, they are often overlooked in management decisions, especially in management for endangered species. One indicator of the low emphasis on invertebrates is the lack of inverte- brates included in both worldwide and U.S. endangered species programs. A review of current U.S. Endangered Species Act listings and policies show that this endangered species program is biased toward vertebrates. We believe there is compelling evidence that agencies, scientists, conservationists, and land managers should do more to promote the conservation of imperiled invertebrates. We briefly outline the steps that need to be taken to protect invertebrates and detail butterfly farming and a pollinator protection campaign as two possible ways to protect and restore invertebrate diversity and habitat.
... In contrast, other species, such as the monarch butterfly, migrate great distances but still face an uncertain future. Rare insect species often have subtle habitat requirements and have even been lost from reserves as a result of apparently minor habitat changes (Thomas 1995). The large blue butterfly (Maculina arion) larvae is an obligate parasite of red ant (Myrimica sabuleti) colonies . ...
... By using a novel human-modified habitat, the butterflies studied here were exposed for the first time to a rare catastrophic event. Calls to protect population sources of endangered species (Groombridge 1992;Thomas 1994;Warren 1994) focus attention on the conservation implications of spatial variation in breeding success, but population sources are not necessarily persistent. Metapopulation conservation may require the protection of habitat heterogeneity and specific habitats where populations are resilient to extinction, and pseudosinks may on occasion be more resilient than sources. ...
Increasing emphasis is being placed on the large-scale and long-term dynamics of populations. A butterfly (Euphydryas editha) metapopulation that was naturally restricted to rocky outcrops in an area of coniferous forest suffered two major perturbations in 30 yr. First, humans clear-cut patches of forest in about 1967. The butterfly colonized the clear-cuts, in which it began to oviposit on a novel host plant, Collinsia torreyi. Breeding success was high, and the clear-cut habitat supported a population source; in the mid-1980s, there was net movement of adults from clear-cut to outcrop, and butterfly densities were elevated on outcrops close to population sources. The second major perturbation came in 1992, when a severe summer frost killed C. torreyi plants (outcrop hosts were not damaged). As a result, E. editha larvae starved in clear-cuts, and the source populations became extinct. This occurrence allowed us to test several predictions of source-sink theory. As predicted, densities declined on outcrops, and particularly on those close to former sources; by 1993, densities on outcrops were no longer correlated with isolation from former sources. True population sinks are predicted to become extinct in the absence of immigration, but this prediction was not observed. Outcrops were not true sinks because E. editha occupied this habitat before the creation of sources, survived the frost on outcrops, and persisted on outcrops in areas where they were isolated from sources. Outcrops were pseudosinks; breeding success was poor at immigration-enhanced densities, but outcrop populations did not rely on immigration to persist. The implications for conservation biology are that populations with high mean density and that act as sources are not necessarily more stable than lower-density or pseudosink populations. This may be especially true of systems subject to recent human disturbance, as in the present case.
Monitoring results on the use of 12 German wildlife overpasses by grasshoppers and crickets (Saltatoria), butterflies and burnets (Lepidoptera; Rhopalocera, Zygaenidae), ground beetles (Coleoptera; Carabidae) and the herpetofauna (Reptilia and Amphibia)
Der Artikel enthält folgende Kapitel: Isolation Aussterben (Extinktion) und Wiederbesiedelung (Kolonisation) Metapopulation Analyse von Metapopulationen – Modelleinsatz und vereinfachte Vorgehensweisen Metapopulation und Naturschutzpraxis Literatur Resümee
The methods and criteria used in the Red Book and European butterfly red lists are discussed and the status of European butterfly species is assessed. The status is identified due to the Species of European Conservation Concern, divided into four categories depending on their global conservation status, their European Threat Status and the proportion of their world range in Europe. The most important threats to European butterflies are ranged. Within the conservation strategy, habitat protection and management, climate change and development of the European butterfly indicators are considered. The Prime Butterfly Areas of Europe identified by European entomologists are discussed. The European Russia faunistic data is not entirely included in recent red butterfly lists and the solution of this problem is discussed.
Range shifts are perhaps the least controversial as well as the most easily observed responses expected under global warming scenarios. While changes at single study sites and along single species’ range boundaries have been studied in a diversity of taxa, the wealth of historical records for butterflies has allowed changes across entire species’ ranges to be analysed. This becomes important in distinguishing local distribution changes from systematic poleward/upward range shifts.
Examination of 58 species in North America and Europe documented poleward shifts of species’ ranges in proportions far higher than one would expect by chance. The magnitudes of the observed range shifts (boundary movement from 35 to 200 km) is on the same order as the magnitudes of regional warming (from 0.7 to 0.8 °C, equating to movement of temperature isotherms by 92 to 120 km).
Coupled with general global warming, extreme weather and climate events have been increasing in magnitude and frequency on a global scale. Previous basic research on butterflies has provided detailed information on the mechanistic links between climate and population dynamics, reproductive behaviour, and extinction/colonisation dynamics. A synthesis of these studies indicates that such extreme climate events have driven observed butterfly range shifts.
The sensitivity of butterflies to climate, the temporal and spatial breadth of distributional data (especially for European species), as well as the wealth of basic biological knowledge, allow studies of butterflies to provide an in-depth understanding of current impacts of climate change on wildlife. Further, the effects of non-climatic global change factors have been studied for many species. Species’ habitat requirements are often well understood, and butterifies have served as useful organisms for studies of habitat fragmentation and restoration. These complementary fields of study, taken together, poise butterflies for being ideal models for understanding the intersecting effects of modern environmental changes, particularly the hardships imposed by climate change across an increasingly hostile landscape.
Zusammenfassung Österreich besitzt mit 187 Papillonoidea-und 25 Hesperioidea-Arten (HUEMER & TARMANN 1993) die höchste Artenvielfalt an Tagfaltern unter den mitteleuropäischen Ländern. Infolge zunehmender Intensivierung der Landwirtschaft und Zerstörung intakter Habitate ist in den letzten Jahrzehnten ein drastischer Rückgang an Tagfalterarten zu verzeichnen. Ein gezielter Arten-und Biotopschutz ist folglich von vordringlichem Interesse. Aufgrund der Vernetzung von verschiedenartigen Standorten hat die Donauinsel für die Tagfalter-Fauna als Rückzugsgebiet im Wiener Stadtgebiet besondere Bedeutung. Im Sommer 1995 erfolgte eine Kartierung der Vegetation und der Tagfalter auf zehn verschiedenen Standorten auf der Donauinsel. Im Zuge der Feldaufnahmen wurden 170 Pflanzenarten, von denen 10 Arten, beispiels-weise die vom Aussterben bedrohten Spezies Agropyron pectinatum (Kamm-Quecke) und Vulpia bromoides (Trespen-Federschwingel), in Gefährdungskategorien der Roten Liste (NIKLFELD et al. 1999) geführt werden, und 32 Tagfalterarten registriert. Besonders erwähnenswert ist das Auftreten der gefährdeten Tagfalterarten Apatura ilia (Kleiner Schillerfalter), Aricia agestis (Kleiner Sonnenröschen-Bläuling), Lycaena dispar rutilus (Großer Feuerfalter) und Plebicula thersites (Esparsetten-Bläuling). Ein Ruderalstandort im Südteil der Donauinsel weist sowohl bei den Pflanzen als auch bei den Tagfaltern die höchste Artenzahl auf. Die ver-schiedenen Landschaftselemente (alter Auwaldrest, alte Baumbestände, Feuchtbiotop, Hecken, Ruderal-flächen etc.), von denen dieser Standort umgeben ist, und die Heterogenität der untersuchten Ruderalfläche bieten vielen Arten günstige Lebensbedingungen. Das artenreiche Auftreten von Tagfaltern auf einer intensiv genutzten Fettwiese im Norden der Insel lässt sich vor allem auf den ungemähten Wiesensaum mit reichem Blühaspekt zurückführen. Generell konnten auf den häufig gemähten Fettwiesen jedoch nur sehr wenige Tag-falterarten nachgewiesen werden. Das Vorhandensein einer ausreichend großen Auswahl an Futter-und Nektarpflanzen ist Grundvoraussetzung für einen großen Artenreichtum an Faltern. Demzufolge ist Artenschutz nur durch Biotopschutz sinnvoll und möglich. Als generelle Richtlinie gilt, dass die untersuchten Flächen höchstens einmal im Jahr gemäht werden sollten und zwar erst Anfang Oktober, mit Ausnahme jener Wiesen, die einem starken Besucherdruck standhalten müssen und deshalb jährlich als Kompromiss einen dreimali-gen Schnitt erfordern. Das Mähgut soll auf Wiesen mit einmaliger Mahd drei bis sieben Tage liegen gelassen werden, um vor allem den Raupen das Flüchten und Auffinden neuer Futterpflanzen zu ermöglichen. Düngung sollte grundsätzlich unterbleiben. Ein Mosaik aus ungestörten Sukzessionsflächen mit Büschen und extensiv genutzten Wiesen ist die pflegerische Grundvoraussetzung für einen erfolgreichen Tagfalter-Artenschutz. Summary Vegetation and Butterflies on the Danube Island: Inventory and Recommendations for Optimising the Cutting-Management of Meadows. With approximately 187 Papillonoidea-und 25 Hesperioidea-species (HUEMER & TARMANN 1993) Austria is by far the richest Central European country concerning lepidopteran speciesdiversity. Due to intense agricultural activities and destruction of existing intact habitats during the last decades, a severe decline of distribution and abundance of the butterfly fauna has been recorded. Too little has been done for conservation, consequently a carefully directed management to protect species and biotopes is urgently needed. The Denisia 03, 151-176 151 © Biologiezentrum Linz/Austria; download unter www.biologiezentrum.at Danube Island with its diverse habitats represents a refugium with special importance because of its location in the Viennese urban area. During fieldwork in summer 1995 ten locations on the Danube Island were investigated with regard to diversity of vegetation and occurrence of butterflies. 170 plant species could be registered, ten of which are classified as endangered in different categories according to the " Red List" for Austria (critically endangered species: Agropyron pectinatum and Vulpia bromoides; NIKLFELD et al. 1999). 32 butterfly species were found, especially noteworthy is the occurrence of the endangered butterflies Apatura ilia, Aricia agestis, Lycaena dispar rutilus and Plebicula thersites. A ruderal site in the south of the Danube Island exhibited the highest numbers of species for plants as well as for butterflies. This diversity is due to the heterogeneity of landscape-elements surrounding the location, such as an old riverine forest, old stocks of trees, wet biotopes, hedges, ruderal sites etc. which create favourable living conditions. The species-rich occurrence of butterflies in an intensively used meadow in the north of the island can be explained by the uncut flowering border zones, which offer a rich nectar-supply for the butterflies. Frequently cut meadows generally accommodate very few butterflies. The presence of a sufficient range of food-and nectar-plants is the basis for a high species richness of butterflies. Therefore, species protection is only practicable in connection with biotope protection. As a general rule the meadows should only be cut once a year at the most early in October, with the exception of those regions, which are frequently visited by people. These areas need to be cut three times a year. The hay should be lying for three to seven days on the meadows cut once a year, in order to allow an escape and the discovery of new food-plants especially for the caterpillars. On principle, no fertilisation should take place. A mosaic of undisturbed areas left to succession, consisting of bushes and extensively used meadows, is the basic requirement to achieve a successful protection of butterfly species.
Effective butterfly conservation is built on five pillars: where are they, how is their trend, what are the drivers, which measures should we take and how can we communicate this knowledge to the relevant stakeholders and the wider public. This thesis focuses on the first three pillars and shows how citizen science and modern modelling techniques provide allow us to assess the distribution of butterflies. From this we can obtain the distribution trend, but also gain insight on the underlying mechanisms: persistence and colonisation. In the Netherlands, the fragmentation of the landscape has led to a decline in colonisation, making it more difficult for butterflies to establish in new habitat patches.
Since 1990 butterfly monitoring has provided us with a wealth of detailed population data. From these abundance changes, we can build important indicators for nature conservation, such as the European Grassland Butterfly Indicator. This indicator shows that since 1990 characteristic butterflies of grasslands have declined by 50%. Main causes for this decline are the intensification of agriculture in Western Europe, and abandonment in Eastern and Southern Europe. Butterflies are also sensitive to climate change. Another indicator, the Climate Change Indicator, shows that butterfly communities change to include more southern ‘warm’ species as compared to northern ‘cool’ species.
Metapopulation theory is a powerful tool to predict the future of populations within a fragmented landscape. By coupling demographic and genetic studies on such a set of populations of the butterfly Proclossiana eunomia, we show that adult dispersal was oriented along river basins. The comparison of allelic frequencies of populations from different river basins revealed that the presence of stepping stone habitats and topographical barriers ar the major factors determining their differentiation. Isolation by distance plays a minor part at the spatial scale considered here.
The extent of semi‐natural grassland has diminished considerably across lowland landscapes of England and Wales during the second half of the twentieth century. Locating, describing and evaluating the dwindling cover has been a major challenge for conservationists. A concentrated vegetation survey effort at grassland sites has been mounted within different parts of Britain since the late 1970s. Plant community recognition has benefited considerably from the development of the contemporary National Vegetation Classification, and its widespread adoption permits national inventory of comparable vegetation data.
Findings of a range of surveys (ninety‐eight in total), undertaken between 1978 and 1996 in England and Wales covering different forms of unimproved lowland grassland, are collated and reviewed. Vegetation data were abstracted from internally published survey reports. Calcicolous and neutral grasslands have been covered more thoroughly than acidic and wet or marshy grasslands. Cover data are summarized at community level. Overall estimates from survey results indicate that there are some 27 500–40 000 ha of calcicolous grassland, 7500–15 000 ha of unimproved neutral pasture and hay meadow, 8000–15 000 ha of acidic grassland and 9000–17 500 ha of wet grassland in lowland England and Wales; these represent only 1–2% of the cover of permanent lowland grassland. Some communities have additional representation in heathlands, mires and upland environments.
Although they require further refinement, the cover data for individual communities provide a context for assessing priorities in site‐based and agri‐environment conservation programmes. It is concluded that, as well as arresting further depletion, it will be necessary to restore and expand lowland grassland habitats to counteract the negative impacts of fragmentation and isolation of various community types, such as the Centaureo–Cynosuretum , which is widely but thinly distributed. Habitat rehabilitation schemes also need to assimilate local patterns of community diversity characteristic of both wet and dry grasslands. It is suggested that reversal of the recent successional trends that followed relaxation of grazing at certain sites might produce a more appropriate balance in the relative cover of coarse tall grasslands and fine short turf. Vegetation surveys provide a source of spatial data for identifying local aggregations of semi‐natural grassland remnants.
While the area of plantation forests continues to increase worldwide, their con-tribution to the conservation of biodiversity is still controversial. There is a particular con-cern on the central role played by natural habitat remnants embedded within the plantation matrix in conserving species-rich insect communities. We surveyed butterXies in maritime pine plantation landscapes in south-western France in 83 plots belonging to seven habitat types (Wve successional stages of pine stands, native deciduous woodlands and herbaceous Wrebreaks). The eVect of plot, habitat and landscape attributes on butterXy species richness, community composition and individual species were analysed with a General Linear Model (GLM), partial Canonical Correspondence Analysis (CCA) and the IndVal method. The most important factors determining butterXy diversity and community composition were the presence of semi-natural habitats (deciduous woodlands and Wrebreaks) at the land-scape scale and the composition of understorey vegetation at the plot scale. Pure eVects of plot variables explained the largest part of community variation (12.8%), but landscape fac-tors explained an additional, independent part (6.7%). Firebreaks were characterized by a higher species richness and both Wrebreaks and deciduous woodlands harboured species not or rarely found in pine stands. Despite the forest-dominated landscape, typical forest butter-Xies were rare and mainly found in the deciduous woodlands. Threatened species, such as Coenonympha oedippus and Euphydryas aurinia, were found in pine stands and in Wre-breaks, but were more abundant in the latter. In the studied plantation forest, the conserva-tion of butterXies depends mainly on the preservation of semi-natural habitats, an adequate understorey management and the maintenance of soil moisture levels.
Analysis of rates of decline for butterflies in the British county of Hertfordshire, from presence/absence data in grid squares before and after 1970, showed that complete extinction took place in 66·9% of 2 km squares occupied before 1970 (average for 18 species). For 12 species of intermediate rarity, a 2 km grid resulted in estimates of decline that were on average 35% higher than estimates based on a 10 km grid, the scale at which butterflies have been mapped nationally. Even estimates of decline based on a 2 km grid are likely to be underestimates because pre-1970 records are incomplete and because 2 km grid squares still conceal declines within squares. In Plebejus argus, for which the exact location of every local population is known in North Wales, a 2 km grid would seriously underestimate declines, for example giving only a 56% loss of grid squares if 90% of local populations were to become extinct. Our results and analysis of simulated distributions indicate that: for a few of the very rarest species, declines on grid maps may closely reflect population losses; for species of intermediate rarity, grid maps identify but underestimate population losses; for common species, population losses fail to be detected on grid maps. Per-population extinction rates for butterflies of intermediate rarity, and even for some relatively or very common species, may have been as high as extinction rates for some of the rarest. Because most of the commoner species initially had many populations per grid square, their declines have been underestimated or have not been detected by existing mapping schemes. We propose a scheme for monitoring changes in the status of common as well as rare butterflies in a network of intensively mapped grid squares at different scales.
We studied the ringlet butterfly (Aphantopus hyperantus) in an area of woodland in eastern England. A. hyperantus occurs in open fields, rides (grassy tracks), and glades within the woodland. Mark-recapture methods showed that exchange rates of adult A. hyperantus between fields and glades can be predicted better by distance-via-rides than by direct distance. Behavioral observations showed that A. hyperantus readily moved from glades into rides but rarely moved from glades into dense woodland. The rides are likely to be corridors that act as conduits between fields and glades. In the A. hyperantus system, connectivity could reduce local extinctions and increase rates of recolonization in the event of local extinction.
Estudiamos a la mariposa de ringlet (Aphantopus hyperantus) en una área boscosa en Inglaterra oriental. A. hyperantus occurre en campos abiertos, camellones (zonas con pasto) y claros dentro del bosque. Métodos de captura-recaptura muestran que las tasas de intercambio entre los campos y los claros son más predicibles por distancia-via-camellones que por distancia directa. Observaciones de compartamiento mostraron que A. hyperantus se desplazaba frecuentemente de los claros a los camellones y raramente lo hizo de los claros al bosque denso. Los camellones son corredores que funcionan como conducto entre los campos abiertos y los claros. En el sistema A. hyperantus la conectividad podría reducir las extinciones locales e incrementar las tasas de recolonización en el caso de extinción local.
A scientifically sound PVA must necessarily be based on a detailed knowledge of habitat requirements as well as demographic and genetic properties of the species under study (Boyce 1992, Loeschcke et al. 1994, McCauley 1995, Wissel et al. 1995, Poethke et al. this volume: 81–92). But while habitat requirements are comparatively well studied for quite a number of species, we have rather poor information on demographic properties like density dependant mortality and natality processes, migration behaviour, and population fluctuation resulting from environmental influences. Even worse is our knowledge about the influence of genetical properties of populations on their long term survival (Allendorf & Leary 1986, Loeschcke et al. 1994).
Abgrenzbare Populationen von Organismen kommen in der Natur meist in Lebensräumen vor, die nicht kontinuierlich verbreitet sind. Das heißt, ein bestimmtes Habitat ist vom nächsten gleichartigen Habitat durch dazwischenliegende Strukturen mit anderen Eigenschaften getrennt. Tiere und Pflanzen, deren Ansprüche nur in solchen Habitat-,Patches'erfüllt sind, treten daher zwangsläufig in voneinander getrennten, also isolierten Einheiten auf. Das Ausmaß einer solchen Isolation ist dabei vor allem abhängig vom Abstand der Patches und von der, Durchlässigkeit'des Zwischenraumes (der sog. Matrix). In ein und derselben Landschaft wird eine solche Isolation für Bewohner derselben Habitat-,Patches'je nach deren Mobilität sehr verschieden ausfallen (z.B. schwach für gute Flieger und stark für nahezu immobile Organismen, wie z.B. Schnecken). Sie ist folglich artspezifisch zu definieren.
To monitor progress towards the European Union target to halt the loss of biodiversity by 2010, biodiversity indicators at a European scale are required. Butterflies have been proposed as biodiversity indicators due to their rapid and sensitive responses to subtle habitat and climatic changes and as representatives for the diversity and responses of other wildlife, especially insects. Since the first butterfly monitoring scheme was established in the UK in 1976, schemes have now been established in over ten European countries. In each scheme, regular butterfly counts are made through the season each year along fixed routes under suitable weather criteria. Here, we used the counts to compile both national and supra-national annual indices for a number of species, in order to develop and test a preliminary European scale biodiversity indicator for the European Environment Agency. A multi-species grassland “European” Butterfly indicator was constructed by combining data from 17 characteristic grassland species, following closely the analytical method developed for the European Bird Indicator. The indicator showed a strong decline in butterfly abundance (of about 40% in 15 years from 1990). The European Environment Agency has subsequently proposed a number of indicators for inclusion in the set of European biodiversity indicators, butterflies being one of the most highest ranked. We hope to update and develop the indicator further (including compiling an indicator for woodland butterflies), make further analytical improvements and extend butterfly monitoring schemes to other countries in order to improve the quality and representativeness of the indicator.
1. We studied factors affecting emigration and immigration behaviour in the butterfly Melitaea cinxia by releasing 882 newly emerged marked butterflies into 16 habitat patches in a network of 64 empty patches on an isolated island (area 1.6 km(2)). 2. Of the 363 butterflies that were recaptured at least once, 40% were recorded in a new patch during their lifetime. Females emigrated earlier and moved further away than males. One-third of males appeared to remain permanently in, whereas females gradually drifted away from, the release patch. 3. High density of butterflies, great abundance of flowers, and large patch area decreased emigration, whereas open landscape around the patch increased emigration. Females that emigrated were on average larger than females that stayed in the patch of release. 4. In total, 152 immigrants were recorded in 32 patches. Numbers of immigrants increased with patch area and abundance of flowering plants. 5. Results on emigration suggest that conserving an isolated butterfly population is more successful in an area with physical barriers to migration than in an open landscape. The possible tendency of butterflies to leave a patch with low density should be taken into consideration in introductions of butterflies to empty habitat patches. 6. Results on immigration indicate the significance of nectar sources and patch size in successful colonization of empty habitat patches.
Abstract Advances in determination of conservation status of insects through evaluation of threats (rather than simple ‘rarity’ alone) help to set priorities for allocation of conservation resources, and formulate effective legislative treatment and field management for the most needy species. Summaries of several recent conservation studies on butterflies exemplify the variety of practical needs, amongst which habitat protection and enhancement is paramount. However, the paucity of biological and distributional information on most Australian insects necessitates considerable flexibility in approach, so that perceptions of conservation need may be highly subjective. Listing species for protection and conservation priority must be viewed as a dynamic process, with opportunity for rapid action, either to list or de-list taxa as research and recovery actions lead to change in perceived or real status and conservation need.
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