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1.
Effects of patch attributes, barriers, and distance between patches on the distribution of a rock-dwelling rodent (Lagidium viscacia) 总被引：1，自引：0，他引：1
We tested whether size of habitat patches and distance between patches are sufficient to predict the distribution of the mountain
vizcacha Lagidium viscacia a large, rock-dwelling rodent of the Patagonian steppe Argentina, or whether information on other patch and landscape characteristics
also is required. A logistic regression model including the distance between rock crevices and depth of crevices, distance
between a patch and the nearest occupied patch, and whether or not there was a river separating it from the nearest occupied
patch was a better predictor of patch occupancy by mountain vizcachas than was a model based only on patch size and distance
between patches. Our results indicate that a simple metapopulation analysis based on size of habitat patches and distance
between patches may not provide an accurate representation of regional population dynamics if patches vary in habitat quality
independently of patch size and features in the matrix alter connectivity.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
2.
We investigated the role of patch attributes and context on patch occupancy of the Lower Keys marsh rabbit (Sylvilagus palustris hefneri). The Lower Keys marsh rabbit is a federally endangered lagomorph endemic to the Lower Keys of Florida. The marsh rabbit occurs in subpopulations on patches of high marsh that interact to form a metapopulation. Between March 1991 and July 1993, all known patches of high marsh in the Lower Keys were surveyed for presence or absence of marsh rabbit pellets three times per year. Of the 59 habitat patches, 20 had pellets present during all of the surveys (occupied patches), 22 had pellets present during at least one survey (variable patches), and 17 never had any pellets present (empty). Ten variables were measured at each of the 59 patches; seven of these variables concerned attributes of the patch (food, cover, patch size), and three were patch context variables (distance of patch to other patches, distance of patch to other features). Two discriminant function analysis (DFA) were performed. The first DFA compared empty patches to occupied patches (both variably and consistently occupied). Patch isolation explained the most variation in patch occupancy followed by area. The second DFA compared the variably occupied sites with the consistently occupied sites, and patch attributes variables involving the type and height of vegetation were significant. Management efforts for the Lower Keys marsh rabbit should be aimed at both improving habitat quality and decreasing distance between patches. 相似文献
3.
Bradley J. Cosentino Robert L. Schooley Christopher A. Phillips 《Landscape Ecology》2010,25(10):1589-1600
Habitat area and isolation have been useful predictors of species occupancy and turnover in highly fragmented systems. However,
habitat quality also can influence occupancy dynamics, especially in patchy systems where habitat selection can be as important
as stochastic demographic processes. We studied the spatial population dynamics of Chrysemys picta (painted turtle) in a network of 90 wetlands in Illinois, USA from 2007 to 2009. We first evaluated the relative influence
of metapopulation factors (area, isolation) and habitat quality of focal patches on occupancy and turnover. Next, we tested
the effect of habitat quality of source patches on occupancy and turnover at focal patches. Turnover was common with colonizations
(n = 16) outnumbering extinctions (n = 10) between the first 2 years, and extinctions (n = 16) outnumbering colonizations (n = 3) between the second 2 years. Both metapopulation and habitat quality factors influenced C. picta occupancy dynamics. Colonization probability was related positively to spatial connectivity, wetland area, and habitat quality
(wetland inundation, emergent vegetation cover). Extinction probability was related negatively to wetland area and emergent
vegetation cover. Habitat quality of source patches strongly influenced initial occupancy but not turnover patterns. Because
habitat quality for freshwater turtles is related to wetland hydrology, a change from drought to wet conditions during our
study likely influenced distributional shifts. Thus, effects of habitat quality of source and focal patches on occupancy can
vary in space and time. Both metapopulation and habitat quality factors may be needed to understand occupancy dynamics, even
for species exhibiting patchy population structures. 相似文献
4.
The distribution of the northern brown bandicoot (Isoodon macrourus), a medium-sized ground-dwelling marsupial, was examined in habitat fragments within the urban landscape of the city of Brisbane,
Australia. From surveys conducted in 68 fragments, bandicoots were found to be present in 33 (49%) despite widespread habitat
loss and fragmentation. Logistic regression analysis revealed that of 13 measured independent variables, functional connectivity
was the only factor that significantly predicted the presence of bandicoots within fragments, with connectivity positively
correlated with the likelihood of occupation. Functional connectivity was equated to the likelihood of bandicoot immigration
into the focal fragment from the nearest occupied fragment, based on the estimated resistance to movement offered by the intervening
matrix. Within Brisbane, riparian habitat fragments typically have a relatively high level of functional connectivity, as
thin strips of vegetation fringing waterways serve as corridors between larger riparian areas and facilitate the movement
of bandicoots between patches. Analyses based on the Akaike Information Criterion revealed that the optimal model based on
landscape context variables was convincingly better supported by the data than the optimal model produced from fragment characteristics.
However, it is important to examine both internal attributes of habitat fragments and external features of the surrounding
landscape when modelling the distribution of ground-dwelling fauna in urban environments, or other landscapes with a highly
variable matrix. As urban centres throughout the world expand, it is crucial that the ecology of local wildlife be considered
to ensure functional connection is maintained between habitat patches, especially for the conservation of species that are
highly susceptible to fragmentation. 相似文献
5.
Tick density and population dynamics are important factors in the ecological processes involved in pathogen circulation in
a habitat. These characteristics of tick populations are closely linked to habitat suitability, which reflects the limiting
ecological factors and landscape features affecting tick populations; however, little work has been done on the regional assessment
of habitat suitability. In this study, a regional model for the distribution and abundance of the tick Ixodes ricinus in central Spain is developed. An occurrence and an abundance model were constructed; climate and vegetation variables were
found to be the main predictors of both occurrence and density in a relatively homogeneous matrix of habitat patches, whereas
topographical variables were found to have small contributions and were therefore discarded. The residuals of the abundance
model showed good correlation with the isolation of each patch. The predictive power of the abundance model was greatly enhanced
by inclusion of the traversability (a measure of the permeability of each patch to the propagules of the metapopulation) and
recruitment (an index of the relative importance of each patch to the traffic through the entire habitat network). The removal
from the landscape of the patches whose recruitment values were in the top 10% has a critical effect on tick density, an effect
not observed when patches are removed at random. These results indicate that permanent tick populations can be sustained only
in landscapes containing a minimum network of viable sites. Graph theory and measurements of patch isolation should prove
to be important elements in the forecasting of tick abundance and the management of the features underlying the landscape
ecology of tick populations and pathogen circulation in the field. 相似文献
6.
For weak flying insects feeding on two different host plants during their life cycle, such as gall-inducing aphids, patch
and matrix characteristics may play a critical role in patch occupancy and population size in occupied patches. The aims of
the present study were to define the basic patch size of Baizongia pistaciae (L) (Aphididae, Fordini), an aphid inducing galls on Pistacia palaestina Boiss (Anacardiaceae) using a genetic approach, and to estimate the impact of landscape structure and patch quality on patch
occupancy and gall density on occupied trees of this aphid and four other closely related species. Using 42 genetic markers
detected by RAPD-PCR in 117 clones of the galling aphid Baizongia pistaciae, we calculated Wright's F statistics and estimated the number of winged migrants between demes. We found that host trees at least 150 m apart supported
genetically differentiated demes of B. pistaciae, and formed distinct patches. Since the annual cycle of this aphid involves alternation between two different hosts, P. palaestina trees and Poaceae roots, patch – the smallest area that sustains a deme – is a relatively small area that must be composed
of at least a single P. palaestina tree and nearby secondary hosts. To assess the impact of landscape structure and patch quality on patch occupancy and gall
abundance in occupied patches, two field surveys of P. palaestina trees in natural Mediterranean maquis were performed. Among the five species of gall-inducing aphids found, B. pistaciae was the most abundant of those surveyed. Host trees were occupied more often in the ecotone, the transition zone between
Mediterranean closed maquis and open bata, than in the maquis. Mature and old trees were more often occupied than young ones,
and shrubs more often than tree-like plants. There was no difference in the proportion of occupied trees between isolated
host trees or those growing in groups. Species richness showed similar trends. We also found no significant differences in
gall abundance in occupied trees among tree quality categories, except that trees growing in the ecotone tended to carry more
galls than those growing in the maquis. In conclusion, the best patch of gall-inducing aphids seems to be a small area, composed
of an old shrub of P. palaestina standing in an open landscape with nearby secondary hosts, grass roots, available for colonization by winged migrants. 相似文献
7.
The distribution and abundance of a species may be simultaneously influenced by both local-scale habitat features and the
broader patch and landscape contexts in which these populations occur. Different factors may influence patch occupancy (presence–absence)
versus local abundance (number of individuals within patches), and at different scales, and thus ideally both occupancy and
abundance should be investigated, especially in studies that seek to understand the consequences of land management on species
persistence. Our study evaluated the relative influences of variables associated with the local habitat patch, hillside (patch
context), and landscape context on patch occupancy and abundance of the collared lizard (Crotaphytus collaris) within tallgrass prairie managed under different fire and grazing regimes in the northern Flint Hills of Kansas, USA. Using
a multi-model information-theoretic approach that accounted for detection bias, we found that collared lizard abundance and
occupancy was influenced by factors measured at both the local habitat and landscape scales. At a local scale, collared lizard
abundance was greatest on large rock ledges that had lots of crevices, high vegetation complexity, and were located higher
up on the hillslope. At the landscape scale, collared lizard abundance and occupancy were both higher in watersheds that were
burned frequently (1–2 year intervals). Interestingly, grazing only had a significant effect on occupancy and abundance within
less frequently burned (4-year burn interval) watersheds. Our results suggest that, in addition to the obvious habitat needs
of this species (availability of suitable rock habitat), land-management practices have the potential to influence collared
lizard presence and abundance in the grasslands of the Flint Hills. Thus, mapping the availability of suitable habitat is
unlikely to be sufficient for evaluating species distributions and persistence in such cases without consideration of landscape
management and disturbance history. 相似文献
8.
Individual movement is a key process affecting the distribution of animals in heterogeneous landscapes. For specialist species in patchy habitat, a central issue is how dispersal distances are related to landscape structure. We compared dispersal distances for cactus bugs (Chelinidea vittiger) on two naturally fragmented landscapes (≤ 4% suitable habitat) with different matrix structures (i.e., vegetation height of nonsuitable habitat between suitable patches). Using mark-release-recapture studies, we determined that most transfers between cactus patches occurred during the mating season. Dispersal distances were reduced by > 50% on the landscape that had reduced structural connectivity due to relatively high matrix structure and low patch density. An experiment with detailed movement pathways demonstrated that greater matrix structure decreased mean step lengths, reduced directionality, and thus decreased net displacement by > 60%. However, habitat edges between two matrix elements that differed substantially in resistance to movement were completely permeable. Therefore, the difference in distributions of dispersal distances between the two landscapes mainly reflected the average resistance of matrix habitat and not the level of matrix heterogeneity per se. Our study highlights the merits of combining estimates of dispersal distances with insights on mechanisms from detailed movement pathways, and emphasizes the difficulty of treating dispersal distances of species as fixed traits independent of landscape structure. 相似文献
9.
Spatial dynamics of the knob-tailed gecko Nephrurus stellatus in a fragmented agricultural landscape
In fragmented landscapes, a species?? dispersal ability and response to habitat condition are key determinants of persistence. To understand the relative importance of dispersal and condition for survival of Nephrurus stellatus (Gekkonidae) in southern Australia, we surveyed 92 woodland remnants three times. This gecko favours early post-fire succession conditions so may be at risk of extinction in the long-unburnt agricultural landscape. Using N-mixture models, we compared the influence of four measures of isolation, patch area and two habitat variables on the abundance and occurrence of N. stellatus, while taking into account detection probability. Patch occupancy was high, despite the long-term absence of fire from most remnants. Distance to the nearest occupied site was the most informative measure of patch isolation, exhibiting a negative relationship with occupancy. Distance to a nearby conservation park had little influence, suggesting that mainland?Cisland metapopulation dynamics are not important. Abundance and occurrence were positively related to ?%-cover of spinifex (Triodia), indicating that niche-related factors may also contribute to spatial dynamics. Patterns of patch occupancy imply that N. stellatus has a sequence of spatial dynamics across an isolation gradient, with patchy populations and source-sink dynamics when patches are within 300?m, metapopulations at intermediate isolation, and declining populations when patches are separated by >1?C2?km. Considering the conservation needs of the community, habitat condition and connectivity may need to be improved before fire can be reintroduced to the landscape. We speculate that fire may interact with habitat degradation and isolation, increasing the risk of local extinctions. 相似文献
10.
Cultural landscapes of Germany are patch-corridor-matrix mosaics for an invasive megaforb 总被引：1，自引：0，他引：1
Predicting the vulnerability of landscapes to both the initial colonisation and the subsequent spread of invasive species
remains a major challenge. The aim of this study was to assess the relative importance of sub-patch level factors and landscape
factors for the invasion of the megaforb Heracleum mantegazzianum. In particular, we tested which factors affect the presence in suitable habitat patches and the cover-percentage within invaded
patches. For this purpose, we used standard (logistic) regression modelling techniques. The regression analyses were based
on inventories of suitable habitat patches in 20 study areas (each 1 km2) in cultural landscapes of Germany. The cover percentage in invaded patches was independent from landscape factors, except
for patch shape, and even unsatisfactorily explained by sub-patch level factors included in the analysis (R
2 = 0.19). In contrast, presence of H. mantegazzianum was affected by both local and landscape factors. Woody habitat structure decreased the occurrence probability, whereas vicinity
to transport corridors (rivers, roads), high habitat connectivity, patch size and perimeter-area ratio of habitat patches
had positive effects. The significance of corridors and habitat connectivity shows that dispersal of H. mantegazzianum through the landscape matrix is limited. We conclude that cultural landscapes of Germany function as patch-corridor-matrix
mosaics for the spread of H. mantegazzianum. Our results highlight the importance of landscape structure and habitat configuration for invasive spread. Furthermore,
this study shows that both local and landscape factors should be incorporated into spatially explicit models to predict spatiotemporal
dynamics and equilibrium stages of plant invasions. 相似文献
11.
Threshold levels of habitat composition for the presence of the long-tailed tit (Aegithalos caudatus) in a boreal landscape 总被引：4，自引：0，他引：4
We assessed the habitat patch occupancy of a deciduous-mixed forest specialist, the long-tailed tit (Aegithalos caudatus), in a 1000 km2 conifer dominated landscape in relation to two landscape parameters, namely proportion and isolation of suitable habitat. Data from five consecutive spring seasons were used and within habitat variation controlled for. The occurrence of long-tailed tits was positively related to the amount of habitat within 1 km2 (p=0.0007) and negatively related to the distance between habitat patches (p<0.0001). When combined, the two variables explained >78% of the variation in local patch occupancy. There were distinct thresholds in these landscape variables for the probability of local long-tailed tit presence. In the model the probability increased from 0.1 to 0.8 when interpatch distance decreased from 500 to 100 m with 5% total habitat coverage. With a total proportion of 15% suitable habitat, the same probability jump occurred when interpatch distance changed from 900 to 500 m. The general importance of defined measurements and quantified threshold levels for species conservation and landscape management is discussed. 相似文献
12.
Edge geometry influences patch-level habitat use by an edge specialist in south-eastern Australia 总被引：1，自引：1，他引：0
We investigated patterns in habitat use by the noisy miner (Manorina melanocephala) along farmland-woodland edges of large patches of remnant vegetation (>300 ha) in the highly fragmented box-ironbark woodlands
and forests of central Victoria, Australia. Noisy miners exclude small birds from their territories, and are considered a
significant threat to woodland bird communities in the study region. Seventeen different characteristics of edge habitat were
recorded, together with the detection or non-detection of noisy miners along 129 500-m segments of patch edge. Habitat characteristics
ranged from patch-level factors related to patch-edge geometry to site-level floristic factors. Backward (stepwise) logistic
regression analyses were used to identify habitat characteristics that were associated with the occupancy of a site by noisy
miners. After accounting for the effects of spatial autocorrelation on the occurrence of noisy miners along edges, we identified
projections of remnant vegetation from the patch edge into the agricultural matrix (e.g., corners of patches, peninsulas of
vegetation) and clumps of trees in the agricultural matrix within 100 m of the edge as significant predictors of the occupancy
of edges by noisy miners. This relationship was also confirmed in two other geographically and floristically distinct habitats
within Victoria. The use of edges with projections by noisy miners may confer advantages in interspecific territorial defence.
In light of these results, we advocate revegetation strategies that attempt to enclose projections within 100 m of the edge,
with fencing placed out to this new boundary, to reduce the likelihood of colonisation and domination of an edge by noisy
miners. Our study highlights the need for greater consideration to be given to the patterns in habitat use by aggressive edge
specialists, particularly in relation to patch-edge geometry and other human-induced components of landscapes. 相似文献
13.
The discipline of landscape ecology recognizes the importance of measuring habitat suitability variables at spatial scales
relevant to specific organisms. This paper uses a novel multi-scale hierarchical patch delineation method, PatchMorph, to
measure landscape patch characteristics at two distinct spatial scales and statistically relate them to the presence of state-listed
endangered yellow-billed cuckoos (Coccyzus americanus occidentalis) nesting in forest patches along the Sacramento River, California, USA. The landscape patch characteristics calculated were:
patch thickness, area of cottonwood forest, area of riparian scrub, area of other mixed riparian forest, and total patch area.
A third, regional spatial variable, delineating the north and south portions of study area was also analyzed for the effect
of regional processes. Using field surveys, the landscape characteristics were related to patch occupancy by yellow-billed
cuckoos. The area of cottonwood forest measured at the finest spatial scale of patches was found to be the most important
factor determining yellow-billed cuckoo presence in the forest patches, while no patch characteristics at the larger scale
of habitat patches were important. The regional spatial variable was important in two of the three analysis techniques. Model
validation using an independent data set of surveys (conducted 1987–1990) found 76–82% model accuracy for all the statistical
techniques used. Our results show that the spatial scale at which habitat characteristics are measured influences the suitability
of forest patches. This multi-scale patch and model selection approach to habitat suitability analysis can readily be generalized
for use with other organisms and systems. 相似文献
14.
Studies on the distribution of mammalian carnivores in fragmented landscapes have focused mainly on structural aspects such
as patch and landscape features; similarly, habitat connectivity is usually associated with landscape structure. The influence
of food resources on carnivore patch use and the important effect on habitat connectivity have been overlooked. The aim of
this study is to evaluate the relative importance of food resources on patch use patterns and to test if food availability
can overcome structural constraints on patch use. We carried out a patch-use survey of two carnivores: the beech marten (Martes foina) and the badger (Meles meles) in a sample of 39 woodland patches in a fragmented landscape in central Italy. We used the logistic model to investigate
the relative effects on carnivore distribution of patch, patch neighbourhood and landscape scale variables as well as the
relative abundance of food resources. Our results show how carnivore movements in fragmented landscapes are determined not
only by patch/landscape structure but also by the relative abundance of food resources. The important take-home message of
our research is that, within certain structural limits (e.g. within certain limits of patch isolation), by modifying the relative
amount of resources and their distribution, it is possible to increase suitability in smaller/relatively isolated patches.
Conversely, however, there are certain thresholds above which an increase in resources will not achieve high probability of
presence. Our findings have important and generalizable consequences for highly fragmented landscapes in areas where it may
not be possible to increase patch sizes and/or reduce isolation so, for instance, forest regimes that will increase resource
availability could be implemented.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
15.
Effective conservation management for species that function as metapopulations requires an understanding of population dynamics
at the landscape scale. The water vole, Arvicola amphibius, is one such species. Water voles have recently undergone a significant decline in the UK, as a result of habitat loss and
predation from the introduced American mink, Neovison vison. Large reed bed and grazing marsh sites can provide refuge habitats for water voles from mink predation, in which case populations
within these sites could sustain metapopulations in the surrounding landscape where conditions are less favourable. We carried
out a study using a stochastic patch occupancy model to determine the long term viability of water vole metapopulations in
the wider landscape around a series of extensive reed bed and grazing marsh sites designated as National Key Sites for water
voles. The results of our model simulations show that a large protected core site, or mainland, is essential in maintaining
the long term viability of these systems. Our results also show how these metapopulations could be enhanced by increasing
patch numbers through habitat creation and/or restoration and suggest what the minimum effective size of created or restored
patches should be. The study shows how population modelling can provide insight into some effective practical ways of enhancing
the viability of water vole metapopulations at the landscape scale. Furthermore it demonstrates that extensive wetlands are
an appropriate focus for water vole conservation measures. 相似文献
16.
Mariano P. Grilli 《Landscape Ecology》2010,25(3):383-394
Studies of patchily distributed insect populations have made clear the importance of host patch size and degree of isolation
in determining the distribution of these populations. For such populations, patch connectivity will have an effect on patterns
of patch occupancy and regional dynamics. In the present study we performed a series of observations to estimate the effect
of landscape structure on the abundance of Delphacodes kuscheli (Homoptera: Delphacidae), vector of “Mal de Río Cuarto” disease to maize. Actively dispersing D. kuscheli individuals were collected in 19 sampling sites during the spring of 2004, using sticky traps placed at 2 m above ground
level. Land use and landscape pattern were quantified, using Landsat 5 TM images for the area where each sampling site was
placed. Four land use categories were considered in the analysis; winter pastures, winter cereals, perennial pasture and stubble.
The spatial pattern analysis program FRAGSTATS was employed to estimate the patch area, patch proximity index, Total Class
Area and the Mean Proximity Index for each of the land use categories in those sites where insect samples were taken. Partial
Least Squares Regression analysis techniques were employed to relate the mean abundance of D. kuscheli and the landscape measures. Eighty percent of the variation of the mean insect abundance was explained by two first PLSR
components. The proximity index of the local host patches, the amount of area left to stubble, local host patch area and total
area of winter pastures were the most important variables affecting the abundance of dispersing D. kuscheli individuals. We found that the abundance of the dispersive fraction of the population of D. kuscheli is affected mostly by the surrounding landscape, particularly by the proximity of other host patches, and the permeability
of the matrix represented by the stubble. 相似文献
17.
Context
North American grassland songbird populations have declined significantly due to habitat loss and fragmentation. Understanding the influence of the surrounding landscape on prairie fragment occupancy is vital for predicting the fate of grassland birds in these heavily altered landscapes.Objectives
We examined the relative importance of local and landscape variables on grassland bird occupancy of prairie fragments using a focal-patch study. We also investigated the spatial scale at which landscape variables were most influential.Methods
We surveyed birds on 29 unplowed prairie fragments in western Minnesota and eastern North and South Dakota. We quantified local habitat on the fragment using vegetation surveys and aerial photographs and the landscape surrounding the fragment out to 4 km using aerial photographs. We analyzed occupancy using multi-model approaches applied to multiple logistic regression.Results
Of 38 species encountered, nine were neither too rare nor too abundant to be analyzed. Predictors of patch occupancy were unique for each bird species, yet general patterns emerged. For eight species, landscape variables were more important than local variables. Mostly, those landscape variables measured configuration (e.g., edge density) and not composition (e.g., percent cover of a particular matrix element). Landscape effects were mostly from variables measured at the greatest extents from the prairie fragment.Conclusions
Using a focal-patch study design we demonstrated the importance of the surrounding landscape, often out to 4 km from the fragment edge, on prairie occupancy by grassland birds. Effective management of grassland songbirds will require attention to the landscape context of prairie fragments.18.
Michael R. Guttery Christine A. Ribic David W. Sample Andy Paulios Chris Trosen John Dadisman Daniel Schneider Josephine A. Horton 《Landscape Ecology》2017,32(3):515-529
Context
Beyond the recognized importance of protecting large areas of contiguous habitat, conservation efforts for many species are complicated by the fact that patch suitability may also be affected by characteristics of the landscape within which the patch is located. Currently, little is known about the spatial scales at which species respond to different aspects of the landscape surrounding an occupied patch.Objectives
Using grassland bird point count data, we describe an approach to evaluating scale-specific effects of landscape composition on patch occupancy.Methods
We used data from 793 point count surveys conducted in idle and grazed grasslands across Wisconsin, USA from 2012 to 2014 to evaluate scale-dependencies in the response of grassland birds to landscape composition. Patch occupancy models were used to evaluate the relationship between occupancy and landscape composition at scales from 100 to 3000 m.Results
Bobolink (Dolichonyx oryzivorus) exhibited a pattern indicating selection for grassland habitats in the surrounding landscape at all spatial scales while selecting against other habitats. Eastern Meadowlark (Sturnella magna) displayed evidence of scale sensitivity for all habitat types. Grasshopper Sparrow (Ammodramus savannarum) showed a strong positive response to pasture and idle grass at all scales and negatively to cropland at large scales. Unlike other species, patch occupancy by Henslow’s Sparrow (A. henslowii) was primarily influenced by patch area.Conclusions
Our results suggest that both working grasslands (pasture) and idle conservation grasslands can play an important role in grassland bird conservation but also highlight the importance of considering species-specific patch and landscape characteristics for effective conservation.19.
Measuring edge effects in complex landscapes is often confounded by the presence of different kinds of natural and anthropogenic
edges, each of which may act differently on organisms inhabiting habitat patches. In such landscapes, proportions of different
habitats surrounding nests within patches often vary and may affect nesting success independently of distance to edges. We
developed methods to measure and study the effects of multiple edges and varying habitat composition around nests on the breeding
success of the Acadian flycatcher (Empidonax virescens), an understory, open-cup nesting songbird. The Kaskaskia River in Southwestern Illinois was our study area and consists
of wide (>1000-m) floodplain corridors embedded in an agricultural matrix with a variety of natural (wide rivers, backwater
swamps, and oxbow lakes) and anthropogenic (internal openings, and agricultural) habitats. We also measured vegetation structure
around each nest. Nest survival increased with increasing nest concealment, and probabilities of brood parasitism increased
with increasing distances from anthropogenic and natural water-related openings surrounding nests. The magnitude of these
effects was small, probably because the landscape is saturated with nest predators and brood parasites. These results illustrate
the importance of considering both larger landscape context and details of natural and anthropogenic disturbances when studying
the effects of habitat fragmentation on wildlife. 相似文献
20.
Petra Janečková Štěpán Janeček Jitka Klimešová Lars Götzenberger Jan Horník Jan Lepš Francesco de Bello 《Landscape Ecology》2017,32(4):791-805