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1.
Fernando R. Silva Thiago A. L. Oliveira James P. Gibbs Denise C. Rossa-Feres 《Landscape Ecology》2012,27(1):87-96
Amphibians are an imperiled group of vertebrate animals that typically have biphasic life histories involving a shift from
aquatic larval habitats to terrestrial adult habitats. Habitat loss is the greatest threat to amphibians and the importance
of the spatial configuration of terrestrial and breeding habitats upon the landscape in determining amphibian persistence
is poorly known. The information gap is particularly acute in tropical landscapes that simultaneously host the greatest and
most imperiled amphibian fauna on Earth. We installed 125 artificial ponds at different distances from forest fragments embedded
in an agricultural matrix in southeastern Brazil. Constructed ponds attracted 13 anuran species; ponds at the forest fragment-matrix
transition hosted a greater abundance and higher species richness of frogs and toads than those installed either far from
or well within forest fragments. Forest fragments larger than 70 ha in agricultural areas harbored more individuals than smaller
fragments. Our results indicate that landscape configuration has an important influence on frog and toad distribution and
abundance in tropical agricultural landscapes and we suggest guidelines for maintaining favorable configurations of aquatic
and terrestrial habitats for conserving this rich and imperiled species suite. 相似文献
2.
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
3.
Habitat fragmentation, patch quality and landscape structure are important predictors for species richness. However, conservation
strategies targeting single species mainly focus on habitat patches and neglect possible effects of the surrounding landscape.
This project assesses the impact of management, habitat fragmentation and landscape structure at different spatial scales
on the distribution of three endangered butterfly species, Boloria selene, Boloria titania and Brenthis ino. We selected 36 study sites in the Swiss Alps differing in (1) the proportion of suitable habitat (i.e., wetlands); (2) the
proportion of potential dispersal barriers (forest) in the surrounding landscape; (3) altitude; (4) habitat area and (5) management
(mowing versus grazing). Three surveys per study site were conducted during the adult flight period to estimate occurrence
and density of each species. For the best disperser B. selene the probability of occurrence was positively related to increasing proportion of wetland on a large spatial scale (radius:
4,000 m), for the medium disperser B. ino on an intermediate spatial scale (2,000 m) and for the poorest disperser B. titania on a small spatial scale (1,000 m). Nearby forest did not negatively affect butterfly species distribution but instead enhanced
the probability of occurrence and the population density of B. titania. The fen-specialist B. selene had a higher probability of occurrence and higher population densities on grazed compared to mown fens. The altitude of the
habitat patches affected the occurrence of the three species and increasing habitat area enhanced the probability of occurrence
of B. selene and B. ino. We conclude that, the surrounding landscape is of relevance for species distribution, but management and habitat fragmentation
are often more important. We suggest that butterfly conservation should not focus only on a patch scale, but also on a landscape
scale, taking into account species-specific dispersal abilities. 相似文献
4.
5.
Strong relations between population trends and spatial distribution have been suggested at the regional scale: declining species
should have more fragmented distributions because decline causes range retractions towards optimal habitats, whereas increasing
species should have more aggregated distributions, because colonization processes are constrained by distance. Most analyses
of the effects of land use changes on animal populations are diachronic studies of population dynamics or synchronic studies
of species habitat selection. Few studies take simultaneously into account temporal changes in habitat distribution and changes
in species spatial distribution. We applied the above rationale to the landscape scale and analysed how population declines,
increases or stability, as diagnosed in a long term study, correlate with population connectivity or fragmentation at that
scale. We used data on changes in faunal distribution and information on temporal changes in the vegetation in a Mediterranean
area that had been subjected to land abandonment. We found that species declining at the landscape scale had retracting fragmented
distributions and that expanding species had expanding continuous distributions. However, for the latter, we suggest that
the factors involved are related to landscape structure and not to dispersal mediated meta-population processes, which are
of little relevance at this local scale. We also show that even species that are numerically stable can show fragmentation
of their distribution and major spatial distribution shifts in response to land use changes, especially in species that have
low occurrence levels or that are associated with transitory habitats such as heterogeneous shrublands (e.g. Sylvia melanocephala). Studying the spatial structure of species distribution patterns at the landscape scale may provide information about population
declines and increases both at the regional and the landscape scale and can improve our understanding of short-term risks
of local extinction. 相似文献
6.
Estimating the consequences of habitat fragmentation on extinction risk in dynamic landscapes 总被引：7，自引：0，他引：7
Analyzing the population dynamic consequences of spatio-temporal changes in landscape structure is a formidable challenge for spatial ecology. One key population dynamic process in fragmented landscapes is the influence of isolation on colonization rate and thereby on the occurrence of species in habitat fragments, but it is not obvious how isolation should be measured in landscapes that are affected by on-going habitat loss and fragmentation. We suggest the following procedure for the measurement of spatio-temporal isolation. First, a historical record of habitat loss and fragmentation in the landscape is prepared based on snapshots of the extent of the suitable habitat for the focal species. Second, a metapopulation model is used to simulate the occurrence of the species in this landscape, assuming the empirically observed landscape change. The model-predicted pattern of habitat occupancy at a particular point in time (usually the present time) is then compared with empirical observations on the occurrence of the species. We describe a metapopulation model that has been constructed for this purpose, and we apply it to a changing landscape of boreal forests in eastern Finland. We give an example on the occurrence of four threatened polyporous fungi in 18 small fragments of old-growth forest. In none of the species does the current isolation of the fragments nor the time since their isolation explain the occurrence of the species in the study fragments, but in three species the model-predicted occupancy probability had a significant effect on the observed abundance of the species. The model-predicted occupancy probabilities were also calculated by ignoring past landscape changes, that is, by assuming that the landscape had remained in the present configuration for a long time. These probabilities had a significant effect on the abundance of only one of the four species, suggesting that the occurrence of the species tracks landscapes changes with a noticable time lag.This revised version was published online in May 2005 with corrections to the Cover Date. 相似文献
7.
Relations between species mobility and life history traits and/or landscape and habitat features are of broad interest to
ecologists and conservation biologists. Here we investigated the reliability of the relations between mobility and (1) resource
grain and (2) morphological traits in butterflies. Results were used to assess the biological realism of morphological traits
associated with flight as mobility proxies. We then investigated how biological, environmental and landscape variables affected
these mobility proxies. We used a multi-species approach on two different sites. Morphological traits were measured on ca.
20 individuals per site, species and sex. Resource distribution was carefully monitored by investigating the spatial distribution
and overlap of larval and adult feeding resources, together representing the resource grain. The spatial extent of individual
station keeping movements was estimated from distances recorded between successive recaptures of individuals from mark-release-recapture
experiments. Morphological traits seemed reliable proxies of mobility, as both variables were strongly correlated. Morphological
variations were related to flight type and spatial dimension of nectar resource. The most striking point was the clear relation
between the index of relative investment in mobility versus fecundity in females with the spatial dimension of adult feeding
resource. Given the generally accepted relation between abdomen volume and female fecundity, this suggests that females might
invest more in fecundity when nectar resources are widespread. Finally, we did not detected effects of landscape structure
on mobility, which indicates that functional grain of resources is more likely to influence mobility and evolution of morphology
in butterflies than landscape connectivity. 相似文献
8.
Much of what is known about avian species-habitat relations has been derived from studies of birds at local scales. It is
entirely unclear whether the relations observed at these scales translate to the larger landscape in a predictable linear
fashion. We derived habitat models and mapped predicted abundances for three forest bird species of eastern North America
using bird counts, environmental variables, and hierarchical models applied at three spatial scales. Our purpose was to understand
habitat associations at multiple spatial scales and create predictive abundance maps for purposes of conservation planning
at a landscape scale given the constraint that the variables used in this exercise were derived from local-level studies.
Our models indicated a substantial influence of landscape context for all species, many of which were counter to reported
associations at finer spatial extents. We found land cover composition provided the greatest contribution to the relative
explained variance in counts for all three species; spatial structure was second in importance. No single spatial scale dominated
any model, indicating that these species are responding to factors at multiple spatial scales. For purposes of conservation
planning, areas of predicted high abundance should be investigated to evaluate the conservation potential of the landscape
in their general vicinity. In addition, the models and spatial patterns of abundance among species suggest locations where
conservation actions may benefit more than one species. 相似文献
9.
The interaction between landscape structure and spatial patterns of plant invasion has been little addressed by ecologists
despite the new insights it can provide. Because of their spatial configuration as highly connected networks, linear wetlands
such as roadside or agricultural ditches, can serve as corridors facilitating invasion at the landscape scale, but species
dynamics in these important habitats are not well known. We conducted a landscape scale analysis of Phragmites australis invasion patterns (1985–2002 and 1987–2002) in two periurban areas of southern Québec (Canada) focusing on the interaction
between the network of linear wetlands and the adjacent land-uses. Results show that, at the beginning of the reference period,
the two landscapes were relatively non-invaded and populations occurred mostly in roadside habitats which then served as invasion
foci into other parts of the landscape. The intrinsic rates of increase of P. australis populations in linear anthropogenic habitats were generally higher than those reported for natural wetlands. Riparian habitats
along streams and rivers were little invaded compared to anthropogenic linear wetlands, except when they intersected transportation
rights-of-way. Bivariate spatial point pattern analysis of colonization events using both Euclidian and network distances
generally showed spatial dependence (association) to source populations. An autologistic regression model that included landscape
and edaphic variables selected transportation rights-of-way as the best predictor of P. australis occurrence patterns in one of the landscapes. Given the high invasion rates observed, managers of linear wetlands should
carefully monitor expansion patterns especially when roads intersect landscapes of conservation or economic value. 相似文献
10.
Duhamel Rémi Quéré Jean-Pierre Delattre Pierre Giraudoux Patrick 《Landscape Ecology》2000,15(2):89-98
The dynamics of microtine rodents show large variations among species and even among populations of a single species. Several studies have shown that landscape structure and predation play a role in these variations. We studied the influence of landscape structure on the spatial distribution and the population dynamics of the fossorial form of the water vole (Arvicola terrestris sherman). The sampling was based on a preliminary five-year survey of a rodent cycle on a regional scale, as well as a method of abundance estimation using surface indices. This survey led to distinguishing epicentres where outbreaks started, and diffusion sections where outbreaks occurred later. Results showed differences in dynamics of spatial distribution of the vole colonies between these two types of sections. This distribution pattern is related to landscape composition and structure. Epicentres are characterized by a higher ratio of open landscape, a lower ratio of forest, and less fragmentation when compared to the diffusion sections. Therefore landscape analysis has the potential of providing a valuable framework for the designing of programs for the early control of A. terrestris populations. 相似文献
11.
Kimberly A. With 《Landscape Ecology》1994,9(1):25-36
To develop a species-centered definition of landscapes, I suggest using a fractal analysis of movement patterns to identify the scales at which organisms are interacting with the patch structure of the landscape. Significant differences in the fractal dimensions of movement patterns of two species indicate that the species may be interacting with the patch structure at different scales. Fractal analysis therefore permits comparisons of landscape perceptions of different species within the same environment.I tested the utility of this fractal application by analyzing the movement patterns of three species of acridid grasshoppers (Orthoptera) in a grassland mosaic. The largest species moved up to 6 times faster than the two smaller species, and species exhibited different responses to microlandscape structure within 25-m2 plots. Further, the largest species exhibited different responses to microlandscape structure in two pastures subjected to different intensities of cattle grazing. This species thus is able to integrate information on landscape structure at broad spatial scales. Fractal analysis of movement patterns revealed that the two small species had significantly more tortuous patterns than the larger species, which suggests that these species are interacting with patch structure at a finer scale of resolution than the large species. Fractal analysis can be used to identify the perceptive resolution of a species; that is, the spatial grain and extent at which they are able to perceive and respond to heterogeneity. Analysis of movement patterns across a range of spatial scale may reveal shifts in fractal dimension that reflect transitions in how species respond to the patch structure of the landscape at different scales. 相似文献
12.
The degree to which habitat fragmentation affects bird incidence is species specific and may depend on varying spatial scales.
Selecting the correct scale of measurement is essential to appropriately assess the effects of habitat fragmentation on bird
occurrence. Our objective was to determine which spatial scale of landscape measurement best describes the incidence of three
bird species (Pyriglena leucoptera, Xiphorhynchus fuscus and Chiroxiphia caudata) in the fragmented Brazilian Atlantic forest and test if multi-scalar models perform better than single-scalar ones. Bird
incidence was assessed in 80 forest fragments. The surrounding landscape structure was described with four indices measured
at four spatial scales (400-, 600-, 800- and 1,000-m buffers around the sample points). The explanatory power of each scale
in predicting bird incidence was assessed using logistic regression, bootstrapped with 1,000 repetitions. The best results
varied between species (1,000-m radius for P. leucoptera; 800-m for X. fuscus and 600-m for C. caudata), probably due to their distinct feeding habits and foraging strategies. Multi-scale models always resulted in better predictions
than single-scale models, suggesting that different aspects of the landscape structure are related to different ecological
processes influencing bird incidence. In particular, our results suggest that local extinction and (re)colonisation processes
might simultaneously act at different scales. Thus, single-scale models may not be good enough to properly describe complex
pattern–process relationships. Selecting variables at multiple ecologically relevant scales is a reasonable procedure to optimise
the accuracy of species incidence models. 相似文献
13.
Judith A. Simon Joel W. Snodgrass Ryan E. Casey Donald W. Sparling 《Landscape Ecology》2009,24(3):361-373
Many amphibian species rely on both aquatic and terrestrial habitats to complete their life cycles. Therefore, processes operating
both within the aquatic breeding habitat, and in the surrounding uplands may influence species distributions and community
composition. Moreover, changes in land use adjacent to breeding site may degrade aquatic habitats. To assess land use effects
on pond-breeding amphibian assemblages, we investigated relationships between land use, breeding habitat conditions, and breeding
amphibian use of constructed wetlands in urban environments of the Baltimore metropolitan area, USA. Forest and impervious
surface associations with species richness and occurrence occurred at spatial scales ranging from 50 to 1,000 m, with strongest
relationships at 500 m. Forest and impervious surface cover within 1,000 m of ponds were also related to water and sediment
quality, which in turn were capable of explaining a proportion of the observed variation in species richness and occurrence.
Taken together, our results suggest that forest and other land covers within relatively proximal distances to ponds (i.e.,
within 50–1,000 m) may be influencing species richness directly via the provisioning of upland habitat, and indirectly via
influences on within pond habitat quality.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
14.
Contemporary landscape ecology continues to explore the causes and consequences of landscape heterogeneity across a range of scales, and demands for the scientific underpinnings of landscape planning and management still remains high. The spatial distribution of resources can be a key element in determining habitat quality, and that in turn is directly related to the level of heterogeneity in the system. In this sense, forest habitat mosaics may be more affected by lack of heterogeneity than by structural fragmentation. Nonetheless, increasing spatial heterogeneity at a given spatial scale can also decrease habitat patch size, with potential negative consequences for specialist species. Such dual effect may lead to hump-backed shape relationships between species diversity and heterogeneity, leading to three related assumptions: (i) at low levels of heterogeneity, an increase in heterogeneity favours local and regional species richness, (ii) there is an optimum heterogeneity level at which a maximum number of species is reached, (iii) further increase in spatial heterogeneity has a negative effect on local and regional species richness, due to increasing adverse effects of habitat fragmentation. In this study, we investigated the existence of a hump-shaped relationship between local plant species richness and increasing forest landscape heterogeneity on a complex mosaic in the French Alps. Forest landscape heterogeneity was quantified with five independent criteria. We found significant quadratic relationships between local forest species richness and two heterogeneity criteria indicators, showing a slight decrease of forest species richness at very high heterogeneity levels. Species richness–landscape heterogeneity relationships varied according to the heterogeneity metrics involved and the type of species richness considered. Our results support the assumption that intermediate levels of heterogeneity may support more species than very high levels of heterogeneity, although we were not able to conclude for a systematic negative effect of very high levels of heterogeneity on local plant species richness. 相似文献
15.
Understanding interactions between roadways and population structure and movements of wildlife is key to mitigating “road
effects” associated with increasing urbanization of the landscape. Aquatic turtles are a useful focal group because (1) population
persistence is sensitive to mortality of individuals upon roads; (2) turtles frequently move among wetlands and encounter
roads, and (3) turtles are an important component of vertebrate biomass in aquatic ecosystems. From 2005 to 2007, we examined
the effects of urbanization on local- and landscape-scale populations of turtles. To do so, we sampled and marked turtles
in 15 ponds arranged along a steep, urban–rural gradient in central New York State. We captured 494 turtles, representing
327 individuals, the majority of which were common snapping turtles Chelydra serpentina (n = 191) and eastern painted turtles Chrysemys picta picta (n = 122). At the local population (pond) scale, a higher proportion of female snapping turtles in ponds was associated with
lower road densities within 500 m of ponds. The mean size of both species of turtle increased in ponds with a lower density
of roads within 100 m. At the landscape-level, we observed fewer turtles dispersing through urbanized habitat than forested,
and fewer movements through areas with a higher density of roads. Our study suggests that roads alter both local- and landscape-level
turtle populations through a loss of female turtles, and by reducing movement between ponds. By extension, the study targets
key landscape features upon which to focus mitigation efforts. 相似文献
16.
Land use changes operate at different scales. They trigger a cascade of effects that simultaneously modify the composition
or structure of the landscape and of the local vegetation. Mobil animals, and birds in particular, can respond quickly to
such multi-scalar changes. We took advantage of a long term study on the response of songbirds to land-use changes on four
Mediterranean islands in Corsica and Sardinia to explore the benefits of a multi-scale analysis of the relationships between
songbird distribution, vegetation structure and landscape dynamics. Field data and aerial photographs were used to describe
the vegetation at three different scales. Birds were censused by point counts. We used statistical variance decomposition
to study how bird distribution and vegetation at various scales were linked. We analysed multi-scale vegetation changes (floristic
composition, plot vegetation type, and landscape structure) and their consequences on bird distribution with multivariate
and non-parametrical tests. The distribution of most species was linked to at least two spatial scales. The weight of a given
scale was consistent with life-history traits for species whose biology was well-known. In the examples studied, vegetation
composition, vegetation type and landscape changes that resulted from land abandonment negatively affected birds depending
on open or heterogeneous areas. Our results emphasize that multi-scale analyses can greatly enhance our understanding of bird
distribution and of their changes. Management of these populations should take into account measures at various spatial scales
depending on the sensitivity of the species. 相似文献
17.
Françoise Burel 《Landscape Ecology》1989,2(4):215-226
Analysis of carabids spatial distribution in a hedgerow network landscape in western France, pinpoints the role of the landscape among other levels of ecological organization.Dispersion of forest species differs among core forest species, peninsula forest species and corridor forest species. Abundance of forest carabid species in a particular hedgerow is related to the positive effect of a dense herbaceous layer and the presence of a tree layer which is enhanced by the presence of two parallel hedgerows, especially along lanes.At the landscape level distance from the largest forest determines abundance of forest species within the first kilometer out of it. Beyond that, abundance is independent of distance from the source forest and the discriminant ecological factors are: hedgerow structure, presence of lanes bordered by two hedgerows. 相似文献
18.
Mira Kattwinkel Barbara Strauss Robert Biedermann Michael Kleyer 《Landscape Ecology》2009,24(7):929-941
The importance of the spatial as well as the temporal structure of habitat patches for urban biodiversity has been recognised,
but rarely quantified. In dynamic environments the rate of habitat destruction and recreation (i.e. the landscape turnover
rate), the minimum amount of potential habitat, its spatial configuration as well as the environmental conditions determining
habitat quality are crucial factors for species occurrence. We analysed species responses to environmental parameters and
to the spatio-temporal configuration of urban brownfield habitats in a multi-species approach (37 plant and 43 insect species).
Species presence/absence data and soil parameters, site age, vegetation structure and landscape context were recorded by random
stratified sampling at 133 study plots in industrial areas in the city of Bremen (Germany). Based on the field data, we predicted
species occurrences by species distribution models using a multi-model inference approach. Predicted species communities were
driven by successional age both at the scale of a single building lot and at the landscape scale. Minimum average succession
time of brownfield habitats required to support all and especially regionally rare species depended on the proportion of available
open space; the larger the potential habitat area the faster the acceptable turnover. Most plant, grasshopper, and leafhopper
species modelled could be maintained at an intermediate turnover rate (mean age of 10–15 years) and a proportion of open sites
of at least 40%. Our modelling approach provides the opportunity of inferring optimal spatio-temporal landscape configurations
for urban conservation management from patch scale species-environment relationships. The results indicate that urban planning
should incorporate land use dynamics into the management of urban biodiversity.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
19.
Shifts in bat community structure related to evolved traits and features of human-altered landscapes 总被引：1，自引：0，他引：1
Population declines for many bat species are associated with rapid, human-induced ecosystem changes. In this context, the
available species pool is determined in part by historical adaptation to the native ecosystem, but the resulting community
structure may be determined principally by the ability of evolved traits to function in the novel context of a human-dominated
ecosystem. To investigate the role of human disturbance as a determinant of bat communities, we surveyed assemblages and species
occurrence rates in 27 agriculturally dominated landscapes exhibiting a gradient of human-induced forest fragmentation in
Indiana, USA. We used multiple linear regression to explore the relationship of landscape environmental variables to species
diversity. We then examined the relationship between community structure, evolved species traits and fragmentation conditions
across a landscape using RLQ analysis. Overall, species diversity was positively related to the amount of forest and negatively correlated with amount
of urban development in a landscape. We also observed a significant relationship between evolved species traits and landscape-level
variables that is consistent with globally anticipated trends for bat species extinction risk. Our findings suggest that responses
of bat species to human modification of ecosystems on the scale of a few kilometers could drive distributional dynamics at
larger spatial and longer temporal scales. 相似文献
20.
The spatial extent at which landscape structure best predicts population response, called the scale of effect, varies across species. An ability to predict the scale of effect of a landscape using species traits would make landscape study design more efficient and would enable landscape managers to plan at the appropriate scale. We used an individual based simulation model to predict how species traits influence the scale of effect. Specifically, we tested the effects of dispersal distance, reproductive rate, and informed movement behavior on the radius at which percent habitat cover best predicts population abundance in a focal area. Scale of effect for species with random movement behavior was compared to scale of effect for species with three (cumulative) levels of information use during dispersal: habitat based settlement, conspecific density based settlement, and gap-avoidance during movement. Consistent with a common belief among researchers, dispersal distance had a strong, positive influence on scale of effect. A general guideline for empiricists is to expect the radius of a landscape to be 4?C9 times the median dispersal distance or 0.3?C0.5 times the maximum dispersal distance of a species. Informed dispersal led to greater increases in population size than did increased reproductive rate. Similarly, informed dispersal led to more strongly decreased scales of effect than did reproductive rate. Most notably, gap-avoidance resulted in scales that were 0.2?C0.5 times those of non-avoidant species. This is the first study to generate testable hypotheses concerning the mechanisms underlying the scale at which populations respond to the landscape. 相似文献