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1.
Nearctic-Neotropical migratory birds are threatened by land-use change throughout their complex annual cycles. While urbanization is an essential driver of land-use change, it is unclear how it affects migrant birds. Although migratory birds are more diverse in non-urban patches of native vegetation than in urban areas, neotropical cities can host diverse assemblages of overwintering migrant birds. Migratory birds in neotropical cities tend to be closely associated with urban green areas (UGAs). However, how their presence and abundance are affected by the habitat elements of UGAs and the urban matrix of neotropical cities is poorly understood. In this study, we compared the migratory bird species richness and abundances among UGAs and the urban matrix of the southern section of the megacity of Mexico City and native vegetation sites outside the city. Our results show that UGAs in neotropical cities provide habitats capable of maintaining complex overwintering migratory bird assemblages with local trees as critical features. We also assess the role that UGAs' characteristics play in determining migrant bird assemblages. We conducted bird censuses and measured habitat traits to determine how migrant bird assemblages are related to the habitat features of our study sites. We measured local, buffer, and spatial habitat features of each UGA. We found 23 overwintering migrant species in the three habitats, with 22 present within UGAs. Both UGAs and urban matrix sites had higher estimated species richness of migrant birds than non-urban native vegetation sites located outside the city. Only local features of UGAs affected migrant birds. While tree abundance in UGAs was positively associated with migratory bird species richness, the proportion of tree coverage was positively related to bird abundance. Our results show that UGAs in neotropical cities can maintain complex overwintering migratory bird assemblages, with trees being the most critical habitat feature. As a result, UGA management focused on maintaining trees and increasing their numbers can improve habitat conditions for migratory birds overwintering in neotropical cities. 相似文献
2.
Isolated trees may significantly enhance biodiversity at the landscape level. However, our understanding of their impacts
is still poor, particularly in environments with high soil moisture where research on this topic has been comparatively limited.
We examined understorey vegetation and soil oribatid mite assemblages under live and dead Scots pine trees and in open treeless
areas, all within the same Scottish upland wet heath system, to determine whether isolated live trees affected the understorey
and mite components of the ecosystem, and whether these effects occurred in parallel. We also explored whether these responses
might result from tree-driven reductions in soil moisture content. Live trees reduced soil moisture (relative to wet heath
and beneath dead trees) and appeared to change vegetation from wet heath to dry heath type communities. These effects were
strongly related to tree trunk diameter (tree size). No major effects of dead trees on understorey vegetation or soil moisture
were apparent. Higher mite species abundance and richness were found under live trees than in treeless open heath. Although
mite abundances were lower under dead trees than live trees, richness remained similar, thus different factors seem to be
regulating mite abundance and community composition. These findings indicate that landscape-level biodiversity responses to
environmental change such as habitat fragmentation cannot be predicted from vegetation patterns alone, and that even in heavily
fragmented landscapes comparatively small patches such as isolated individual trees can enhance biodiversity. 相似文献
3.
4.
Landscape structure and breeding bird distribution in a sub-Mediterranean agro-ecosystem 总被引:7,自引:0,他引:7
Richness, abundance and distribution of birds were investigated in the Aulella watershed,a mountainous area of 300 km2, located in the extreme northwestern corner of Tuscany, Italy in spring and summer, 1995. The study area encompasses five
vegetation types (from Mediterranean maqui to upland beech forest) and three main land use categories (woodlands, mixed cultivated
+ urban areas, montane prairies). The recent history of land abandonment in the study area has produced a rapid expansion
of shrubland and woodland, reducing cultivated areas to small patches interspersed in a woodland matrix. Richness, abundance
and distribution of birds recorded at 414 points, randomly selected along secondary roads, and located using a Global Positioning
System (GPS), were compared with topography, vegetation type and land use in a Geographic Information Systems (GIS) with a
grid cell resolution of 200 × 200 m.
Bird richness (55 species in all) and abundance are correlated: (a) negatively with the increasing altitude and increasing
distance from cultivated areas; (b) positively with the increasing distance from woodlands and mountain prairies. Slope orientation
appears to have a negligible effect on bird assemblages.
Bird richness and abundance are significantly correlated with vegetation type. Cultivated areas support the highest bird richness
and abundance that increase with patch size of the cultivated areas. Local extinction and/or reduction in within-species abundance
of birds are expected to continue if the process of land abandonment continues.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
5.
Urbanization affects amphibian communities through habitat loss, fragmentation, and degradation of habitat quality. The effects of these changes in habitat at different scales vary depending on the sensitivity of individual species. We assessed the breeding distribution of anurans along an urban–rural gradient in Shanghai, China, a region experiencing intensive urbanization. Our results showed that urban density had a significantly negative influence on the overall anuran abundance and diversity and that the responses of individual species to urbanization varied. Pond age was an overall predictor in models describing the responses of Pelophylax nigromaculatus, Fejervarya multistriata, and M. fissipes and total anuran abundance. The quality of habitat at a pond was also important, and the high abundance of Bufo gargarizans and Pelophylax plancyi was associated with ponds with aquatic vegetation coverage. Urban density showed strong negative effects on B. gargarizans, total anuran abundance, and species richness. The broad-scale landscape variables associated with forests, agricultural fields, and wetlands surrounding breeding ponds have been shown to affect anuran abundance and species richness. The response of individual species, total abundance, and species richness to urbanization reflected differences in their ecological requirements. We quantified the effects of urbanization on frogs in a rapidly urbanizing region, and our results demonstrated that both multi-spatial and temporal variables affect anurans in Shanghai. Our results emphasized the importance of anuran conservation planning in urbanized areas to preserve and/or restore terrestrial habitat and to improve connectivity between ponds and other wetlands. 相似文献
6.
A comprehensive understanding of variables associated with spatial differences in community composition is essential to explain
and predict biodiversity over landscape scales. In this study, spatial patterns of bird diversity in Central Kalimantan, Indonesia,
were examined and associated with local-scale (habitat structure and heterogeneity) and landscape-scale (logging, slope position
and elevation) environmental variables. Within the study area (c. 196 km2) local habitat structure and heterogeneity varied considerably, largely due to logging. In total 9747 individuals of 177
bird species were recorded. Akaike's information criterion (AIC) revealed that the best explanatory models of bird community
similarity and species richness included both local- and landscape-scale environmental variables. Important local-scale variables
included liana abundance, fern cover, sapling density, tree density, dead wood abundance and tree architecture, while important
landscape-scale variables were elevation, logging and slope position. Geographic distance between sampling sites was not significantly
associated with spatial variation in either species richness or similarity. These results indicate that deterministic environmental
processes, as opposed to dispersal-driven stochastic processes, primarily structure bird assemblages within the spatial scale
of this study and confirm that highly variable local habitat measures can be effective means of predicting landscape-scale
community patterns. 相似文献
7.
Abel Bernadou Régis Céréghino Hugues Barcet Maud Combe Xavier Espadaler Vincent Fourcassié 《Landscape Ecology》2013,28(7):1387-1400
Of particular importance in shaping species assemblages is the spatial heterogeneity of the environment. The aim of our study was to investigate the influence of spatial heterogeneity and environmental complexity on the distribution of ant functional groups and species diversity along altitudinal gradients in a temperate ecosystem (Pyrenees Mountains). During three summers, we sampled 20 sites distributed across two Pyrenean valleys ranging in altitude from 1,009 to 2,339 m by using pitfall traps and hand collection. The environment around each sampling points was characterized by using both physical and land-cover variables. We then used a self-organizing map algorithm (SOM, neural network) to detect and characterize the relationship between the spatial distribution of ant functional groups, species diversity, and the variables measured. The use of SOM allowed us to reduce the apparent complexity of the environment to five clusters that highlighted two main gradients: an altitudinal gradient and a gradient of environmental closure. The composition of ant functional groups and species diversity changed along both of these gradients and was differently affected by environmental variables. The SOM also allowed us to validate the contours of most ant functional groups by highlighting the response of these groups to the environmental and land-cover variables. 相似文献
8.
Influence of within-field and landscape factors on aphid predator populations in wheat 总被引:3,自引:0,他引:3
Elliott Norman C. Kieckhefer Robert W. Lee Jang-Hoon French Bryan W. 《Landscape Ecology》1999,14(3):239-252
The influence of prey density, within-field vegetation, and the composition and patchiness of the surrounding landscape on the abundance of insect predators of cereal aphids was studied in wheat fields in eastern South Dakota, USA. Cereal aphids, aphid predators, and within-field vegetation were sampled in 104 fields over a three year period (1988–1990). The composition and patchiness of the landscape surrounding each field were determined from high altitude aerial photographs. Five landscape variables, aggregated at three spatial scales ranging from 2.6 km2 to 581 km2, were measured from aerial photographs. Regression models incorporating within-field and landscape variables accounted for 27–49% of the variance in aphid predator abundance in wheat fields. Aphid predator species richness and species diversity were also related to within-field and landscape variables. Some predators were strongly influenced by variability in the composition and patchiness of the landscape surrounding a field at a particular spatial scale while others responded to variability at all scales. Overall, predator abundance, species richness, and species diversity increased with increasing vegetational diversity in wheat fields and with increasing amounts of non-cultivated lands and increasing patchiness in the surrounding landscape. 相似文献
9.
Changes in ecosystem structure caused by urbanization produce a reduction in photosynthetic productivity, which can lead to reductions in resource availability for birds. Here, we analyzed the relation between photosynthetic productivity and bird assemblages in a subtropical urban ecosystem, in North-Western Argentina. We used Generalized Linear Models to assess the responses of bird abundance, richness and diversity to photosynthetic productivity, vegetation cover and distance to main natural forest. We found higher bird richness and diversity with increasing photosynthetic productivity and vegetation cover, and with decreasing distance to forests; while total bird abundance was positively related to vegetation cover. When we classified bird species in different groups, based on their use of the environment, we found that species adapted to urban environments were more dependent on photosynthetic productivity, while species related to native forests were more dependent on the distance to source forests. Understanding the factors that affect bird assemblages in cities is important for the development of strategies for urban planning and conservation. 相似文献
10.
Context
Habitat loss and habitat fragmentation negatively affect amphibian populations. Roads impact amphibian species through barrier effects and traffic mortality. The landscape variable ‘accessible habitat’ considers the combined effects of habitat loss and roads on populations.Objectives
The aim was to test whether accessible habitat was a better predictor of amphibian species richness than separate measures of road effects and habitat loss. I assessed how accessible habitat and local habitat variables determine species richness and community composition.Methods
Frog and tadpole surveys were conducted at 52 wetlands in a peri-urban area of eastern Australia. Accessible habitat was delineated using a highway. Regressions were used to examine relationships between species richness and eleven landscape and local habitat variables. Redundancy analysis was used to examine relationships between community composition and accessible habitat and local habitat variables.Results
Best-ranked models of species richness included both landscape and local habitat variables. There were positive relationships between species richness and accessible habitat and distance to the highway, and uncertain relationships with proportion cover of native vegetation and road density. There were negative relationships between species richness and concreted wetlands and wetland electrical conductivity. Four species were positively associated with accessible habitat, whereas all species were negatively associated with wetland type.Conclusions
Barrier effects caused by the highway and habitat loss have negatively affected the amphibian community. Local habitat variables had strong relationships with species richness and community composition, highlighting the importance of both availability and quality of habitat for amphibian conservation near major roads.11.
Howell Christine A. Latta Steven C. Donovan Therese M. Porneluzi Paul A. Parks Geoffrey R. Faaborg John 《Landscape Ecology》2000,15(6):547-562
We examine the influence of both local habitat and landscape variables on avian species abundance at forested study sites situated within fragmented and contiguous landscapes. The study was conducted over a six year period (1991–1996) at 10 study sites equally divided between the heavily forested Missouri Ozarks and forest fragments in central Missouri. We found greater species richness and diversity in the fragments, but there was a higher percentage of Neotropical migrants in the Ozarks. We found significant differences in the mean number of birds detected between the central Missouri fragments and the unfragmented Ozarks for 15 (63%) of 24 focal species. We used stepwise regression to determine which of 12 local vegetation variables and 4 landscape variables (forest cover, core area, edge density, and mean patch size) accounted for the greatest amount of variation in abundance for 24 bird species. Seven species (29%) were most sensitive to local vegetation variables, while 16 species (67%) responded most strongly to one of four landscape variables. Landscape variables are significant predictors of abundance for many bird species; resource managers should consider multiple measures of landscape sensitivity when making bird population management decisions.Order of first two authors decided by coin toss 相似文献
12.
Community structure of dung beetles in Amazonian savannas: role of fire disturbance,vegetation and landscape structure 总被引:1,自引:0,他引:1
Julio Louzada Albertina P. Lima Rodrigo Matavelli Ludimila Zambaldi Jos Barlow 《Landscape Ecology》2010,25(4):631-641
Understanding the relative influence of environmental and spatial variables in driving variation in species diversity and
composition is an important and growing area of ecological research. We examined how fire, local vegetation structure and
landscape configuration interact to influence dung beetle communities in Amazonian savannas, using both hierarchical partitioning
and variance partitioning techniques to quantify independent effects. We captured a total of 3,334 dung beetles from 15 species
at 22 savanna plots in 2003. The species accumulation curve was close to reaching an asymptote at a regional scale, but curves
were variable at the plot level where total abundance ranged from 17 to 410 individuals. Most plots were dominated by just
three species that accounted for 87.7% of all individuals sampled. Hierarchical partitioning revealed the strong independent
and positive effect of percentage forest cover in the surrounding landscape on total dung beetle abundance and species richness,
and richness of uncommon species and the tunneler guild. Forest cover also had a negative effect on community evenness. None
of the variables that related to fire affected community metrics. The minimal direct influence of fire was supported by variance
partitioning: partialling out the influence of spatial position and vegetation removed all of the individual explanation attributable
to fire, whereas 8% of the variance was explained by vegetation and 28% was explained by spatial variables (when partialling
out effects of the other two variables). Space-fire and vegetation-fire joint effects explained 14 and 10% of the dung beetle
community variability, respectively. These results suggest that much of the variation in dung beetle assemblages in savannas
can be attributed to the spatial location of sites, forest cover (which increased the occurrence of uncommon species), and
the indirect effects of fires on vegetation (that was also dependent on spatial location). Our study also highlights the utility
of partitioning techniques for examining the importance of environment variables such as fire that can be strongly influenced
by spatial location. 相似文献
13.
Despite good theoretical knowledge about determinants of plant species richness in mosaic landscapes, validations based on
complete surveys are scarce. We conducted a case study in a highly fragmented, traditional agricultural landscape. In 199
patches of 20 representative multi-patch-plots (MPPs, 1 ha) we recorded a total of 371 plant species. In addition to an additive
partitioning of species diversity at the (a) patch- and (b) MPP-scale, we adopted the recently proposed ‘specificity’ measure
to quantify the contribution of a spatial subunit to landscape species richness (subunit-to-landscape-contribution, SLC).
SLC-values were calculated at both scales with respect to various spatial extents. General regression models were used to
quantify the relative importance of hypothesis-driven determinants for species richness and SLC-values.
At the patch scale, habitat type was the main determinant of species richness, followed by area and elongated shape. For SLC-values,
area was more important than habitat type, and its relevance increased with the extent of the considered landscape. Influences
of elongated shape and vegetation context were minor. Differences between habitat types were pronounced for species richness
and also partly scale-dependent for SLC-values.
Relevant predictors at the MPP-scale were nonlinear habitat richness, the gradient from anthropogenic to seminatural vegetation,
and the proportions of natural vegetation and rare habitats. Linear elements and habitat configuration did not contribute
to species richness and SLC. Results at the MPP-scale were in complete accordance with the predictions of the mosaic concept.
Hence, our study represents its first empirical validation for plant species diversity in mosaic landscapes. 相似文献
14.
Rune H. Økland Harald Bratli Wenche E. Dramstad Anette Edvardsen Gunnar Engan Wendy Fjellstad Einar Heegaard Oddvar Pedersen Heidi Solstad 《Landscape Ecology》2006,21(7):969-987
Knowledge of variation in vascular plant species richness and species composition in modern agricultural landscapes is important
for appropriate biodiversity management. From species lists for 2201 land-type patches in 16 1-km2 plots five data sets differing in sampling-unit size from patch to plot were prepared. Variation in each data set was partitioned
into seven sources: patch geometry, patch type, geographic location, plot affiliation, habitat diversity, ecological factors,
and land-use intensity. Patch species richness was highly predictable (75% of variance explained) by patch area, within-patch
heterogeneity and patch type. Plot species richness was, however, not predictable by any explanatory variable, most likely
because all studied landscapes contained all main patch types – ploughed land, woodland, grassland and other open land – and
hence had a large core of common species. Patch species composition was explained by variation along major environmental complex
gradients but appeared nested to lower degrees in modern than in traditional agricultural landscapes because species-poor
parts of the landscape do not contain well-defined subsets of the species pool of species-rich parts. Variation in species
composition was scale dependent because the relative importance of specific complex gradients changed with increasing sampling-unit
size, and because the amount of randomness in data sets decreased with increasing sampling-unit size. Our results indicate
that broad landscape structural changes will have consequences for landscape-scale species richness that are hard or impossible
to predict by simple surrogate variables. 相似文献
15.
Ecological theory predicts a positive influence of local-, landscape-, and regional-scale spatial environmental heterogeneity
on local species richness. Therefore, knowing how heterogeneity measured at a variety of scales relates to local species richness
has important implications for conservation of biological diversity. We took a statistical modeling approach to determine
which metrics of heterogeneity measured at which scales were useful predictors of local species richness, and whether the
heterogeneity-local richness relationship was always positive. Local plant species richness data came from 400-m2 vegetation plots in North and South Carolina, USA. At each of four scales from within plots to across regions, we used either
GIS or field data to calculate measures of heterogeneity from abiotic environmental variables, vegetation productivity data,
and land cover classifications. Among all predictors at all scales, we found that no measure of heterogeneity was a better
predictor of local richness than mean pH within plots. However, at scales larger than within plots, measures of heterogeneity
were correlated most strongly with local richness, and each of the three classes of variables we used had a distinct scale
at which it performed better than the others. These results highlight the fact that ecological processes occurring across
multiple scales influence local species richness differently. In addition, relationships between heterogeneity and richness
were usually, though not always, positive, underscoring the importance of processes that occur at a variety of scales to local
biodiversity conservation and management. 相似文献
16.
Protecting semi-natural grasslands may through spill-over benefit species richness and abundance of flower-visiting insects in linear habitats, such as uncultivated field boundaries, in agricultural landscapes. However, whether local diversity increases both with decreasing distance from potential source habitats and increasing landscape heterogeneity is poorly known due to a general lack of studies replicated at the landscape scale. We analysed if local assemblages of bumblebees, butterflies and hoverflies in linear uncultivated habitats increased with increasing distance to the nearest semi-natural grassland in 12 replicated landscapes along a gradient of landscape heterogeneity in Scania, Southern Sweden. Species richness and abundance of bumblebees and butterflies, but not hoverflies, decreased with increasing distance to semi-natural grasslands, but none of these groups were related to increasing landscape heterogeneity. Further analyses on trait-specific groups revealed significant decreases in the abundance of sedentary and grassland specialist butterflies with increasing distance to assumed source populations, whereas this was not the case concerning mobile species and grassland generalists. The abundance of all bumblebee trait groups decreased with increasing distance to semi-natural grasslands, but only some species (those nesting above ground, with long colony cycles and with small colony sizes) also increased with increasing landscape heterogeneity. We conclude that local species assemblages of flower-visiting insects in linear habitat elements were mainly affected by the occurrence of nearby semi-natural grasslands. In order to conserve diverse assemblages of flower-visiting insects, including the ecological services they provide, it is important to conserve semi-natural grasslands dispersed throughout agricultural landscapes. 相似文献
17.
Context
Climate change alters the vegetation composition and functioning of ecosystems. Measuring the magnitude, direction, and rate of changes in vegetation composition induced by climate remains a serious and unmet challenge. Such information is required for a predictive capability of how individual ecosystem will respond to future climates.Objectives
Our objectives were to identify the relationships between 20 climate variables and 39 ecosystems across the southwestern USA. We sought to understand the magnitude of relationships between variation in vegetation composition and bioclimatic variables as well as the amount of ecosystem area expected to be affected by future climate changes.Methods
Bioclimatic variables best explaining the plant species composition of each ecosystem were identified. The strength of relationships between beta turnover and bioclimate gradients was calculated, the spatial concordance of ecosystem and bioclimate configurations was shown, and the area of suitable climate remaining within the boundaries of contemporary ecosystems under future climate projections was measured.Results
Across the southwestern USA, four climate variables account for most of the climate related variation in vegetation composition. Twelve ecosystems are highly sensitive to climate change. By 2070, two ecosystems lose about 4000 (15 %) and 7000 (31 %) km2 of suitable climate area within their current boundaries (the Western Great Plains Sandhill Steppe and Sonora-Mojave Creosotebush-White Bursage Desert Scrub ecosystems, respectively). The climatic areas of riparian ecosystems are expected to be reduced by half.Conclusions
Results provide specific climate and vegetation parameters for anticipating how, where and when ecosystem vegetation transforms with climate change. Projecting the loss of suitable climate for the vegetation composition of ecosystems is important for assessing ecosystem threats from climate change and for setting priorities for ecosystem conservation and restoration across the southwestern USA.18.
Urban parks comprise diverse microhabitats, such as vegetation units of lawn and arbour forests, with differing biodiversity potentials. However, the influences of microhabitats on butterfly diversity and the mechanisms involved remain unclear. This study used butterfly survey data from 112 plots in 27 urban parks in the central metropolitan area of Beijing, China, from June to September 2020. Based on the growth form of larval host plants, recorded butterfly species were classified into three functional groups: woody plant-feeding taxa (WF), herb-feeding taxa (HF), and feeding on multiple plant growth forms taxa (MF). We analysed the effects of 11 variables among three facets, namely, vegetation composition, vegetation structure, and human activity, on the butterfly diversity (species richness and abundance) of the whole community, three functional groups using generalised linear mixed models. Twenty-five butterfly species observed mainly feed on herbs rather than on woody plants. Our results demonstrated that vegetation community characteristics explain up to 24% and 43% variation in butterfly species richness and abundance, respectively. Of this, vegetation structure facets crucially affected butterfly species richness, and vegetation composition facets had the most significant influence on the abundance of the whole butterfly community. However, the impact of human activity factors was minimal. Light availability and herb height belonging to vegetation structure factors and nectar plant species richness and nectar abundance which belonged to vegetation composition factors showed the most important and positive effects on butterfly diversity. The positive impact of the above significant factors was found especially on herb-feeding butterfly diversity. In contrast, the diversity of butterflies feeding on woody plants was most positively influenced by herb height. We thus suggest that it is necessary to guarantee the presence of a well-developed herb layer, which provides abundant nectar sources and maintain specific open spaces to ensure light availability. In conclusion, our findings imply that the critical role of the spatial structure of vegetation community is conspicuous in the formation of suitable microhabitats for butterflies, and managers could combine vegetation management practices with the needs of specific functional groups. 相似文献
19.
Philip S. Barton Karen Ikin Annabel L. Smith Christopher MacGregor David B. Lindenmayer 《Landscape Ecology》2014,29(4):703-714
Ecological theory predicting the impact of fire on ecological communities is typically focused on post-disturbance recovery processes or on disturbance-diversity dynamics. Yet the established relationship between vegetation structure and animal diversity could provide a foundation to predict the short-term effects of fire on biodiversity, but has rarely been explored. We tested the hypothesis that fire effects on bird assemblages would be moderated by increasing vegetation structure. We examined bird assemblages in burnt and unburnt sites at 1 and 6 years after a wildfire, and compared richness and composition responses among and within three structurally distinct vegetation types in the same landscape: heath, woodland and forest. We found that short-term changes in bird assemblage composition were largest in simple heath vegetation and smallest in complex forest vegetation. The short-term change in species richness was larger in forest than in heath. We also found that among-site assemblage variability was greater shortly after fire in heath and woodland vegetation compared with forest vegetation. Our results indicate that complexity in vegetation structure, particularly overstorey cover, can act as an important moderator of fire effects on bird assemblages. Mechanisms for this response include a greater loss of structure in vegetation characterised by a single low stratum, and a proportionally greater change in bird species composition despite a smaller absolute change in species richness. We discuss our results in the context of a new conceptual model that predicts contrasting richness and composition responses of bird assemblages following disturbance along a gradient of increasing vegetation structure. This model brings a different perspective to current theories of disturbance, and has implications for understanding and managing the effects of fire on biodiversity in heterogeneous landscapes. 相似文献
20.
Land cover change, predominantly habitat conversion to agricultural use and urbanization, has recently been recognized as
the primary cause of biodiversity loss in terrestrial ecosystems. We evaluated the relative effects of urban and agricultural
landscapes on anuran species richness and the abundance of six anuran species found at breeding ponds in and around the cities
of Ottawa, Ontario and Gatineau, Quebec. We performed six call surveys at 29 permanent focal ponds surrounded by one of three
landscape contexts: primarily urban, primarily agricultural, and primarily forested. We also measured three local pond variables
to control for the effects of local habitat quality in our analyses. We found that anuran species richness was significantly
lower in breeding ponds in urban landscapes compared to forested and agricultural landscapes, which exhibited no significant
difference in species richness. The abundances of individual anuran species were also consistently lower in urban landscapes
for all species except one, which exhibited no response to landscape type. Three species had their highest abundances in ponds
in forested landscapes, whereas two species had their highest abundances in ponds in agricultural landscapes. We conclude
that ponds embedded in urban landscapes support lower biodiversity than ponds in agricultural settings. We suggest that landscapes
composed of a mosaic of forest and open habitats surrounding wetlands would hold the highest biodiversity of these species. 相似文献