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1.
To assess corridor effects on movement in Peromyscus polionotus (old-field mice), we used a set of three experimental landscapes that contained multiple patches (1.64 ha) of usable, open habitat embedded in a loblolly pine (Pinus taeda) forest matrix. Some patches were connected by corridors and others were isolated (unconnected). We introduced mice to nest boxes in experimental patches and followed them through the landscapes via trapping. We found weak evidence that the presence of corridors decreased the probability that P. polionotus (particularly females) would disperse or disappear from a patch. In the process of live trapping the patches, we also encountered `feral' P. polionotus, Sigmodon hispidus (cotton rats), and Peromyscus gossypinus (cotton mice). The average number of feral animals did not differ between isolated and connected patches. This suggests that corridors do not act as drift fences that `sieve' individuals out of the matrix and into the patches. However, more male than female P. polionotus and S. hispidus were trapped in isolated patches. This intersexual difference did not exist in connected patches. 相似文献
2.
Nest locations of breeding birds are often spatially clustered. This tendency to nest together has generally been related
to a patchy distribution of nesting habitat in landscape studies, but behavioral studies of species with clustered breeding
patterns draw attention to the importance of social and biotic factors. Indeed, it is becoming increasingly apparent that
the breeding system of many territorial, migrant birds may be semi-colonial. The reasons for, and extent of, spatial clustering
in their breeding systems are not well understood. Our goal was to tease apart the influence of habitat availability and social
drivers of clustered breeding in a neotropical migrant species, the hooded warbler (Wilsonia citrina). To test alternative hypotheses related to clustered habitat or conspecific attraction, we combined a habitat classification
based on remote sensing with point pattern analysis of nesting sites. Nest locations (n = 150, 1999–2004), collected in a 1213 ha forested area of Southern Ontario (Canada), were analyzed at multiple spatial scales.
Ripley’s K and pair-correlation functions g (uni- and bivariate) were used to test whether nests were clustered merely because potential nesting habitat was also clustered,
or whether nests were additionally clustered with respect to conspecifics. Nest locations tended to be significantly clustered
at intermediate distances (particularly between 240 and 420 m). Nests were randomly distributed within available habitat at
larger distance scales, up to 1500 m. A reasonable hypothesis to explain the detected additional clustering, and one that
is consistent with the results of several behavioral studies, is that females pack their nests more tightly than the available
habitat requires to be situated closer to their neighbors’ mates. Linking spatially explicit, point pattern analysis with
strong inference based on Monte Carlo tests may bring us closer to understanding the generality and reasons behind conspecific
attraction at different spatial scales.
F. Csillag—deceased. 相似文献
3.
The crested ibis (Nipponia nippon), a species at the brink of extinction in 1981, remain restricted to a small (25 km radius) area of temperate forests in
central China. To improve the chances of successful reintroduction into new areas we developed a multifactor logistic regression
model of habitat association at multiple scales. Using habitat variables, i.e. vegetation, human impact, elevation, and wetland,
we compared occupied and unoccupied sites at grain sizes ranging from 1 to 6400 ha. The goodness-of-fit of the habitat suitability
model depended on grain size, with the best fit (most information) at a grain size of 2 ha. Semivariograms showed the habitat
variables at control sites have a gradient pattern, yet the crested ibis had their specific habitat preferences, and only
selected a narrow range from the available gradient. Our results indicated that spatial scale needs to be considered in developing
habitat models for applications such as conservation planning. 相似文献
4.
Use of space by the yellow-footed antechinus, Antechinus flavipes, in a fragmented landscape in South Australia 总被引:2,自引:1,他引:1
An understanding of how individual species are able to persist and move within fragmented landscapes is critical for elucidating
the effects of fragmentation and aiding in the management of species. Here, we studied movement behaviour of the dasyurid
Antechinus flavipes in a heavily fragmented landscape using trapping and radiotracking. We assessed the ability of animals to move within and
amongst small (<6 ha) remnants and make use of the matrix, and investigated how females used the available space within remnants.
Seventeen between-remnant movements were detected from 428 recaptures, ranging in length from 30 to 720 m and averaging 352
m. Most were by adult males during the breeding season, with 40% more than 500 m. Landscape types traversed would have included
exotic pine plantations, open grazed areas and roads. Between-site movements of juveniles were only detected on three occasions.
However, few young males were captured as adults, suggesting high dispersal rates and considerable matrix use. Conversely,
despite high female recapture rates, again only three between-site movements were recorded. Radiotracking further indicated
that females confined foraging to remnants, with occasional forays to isolated trees in paddocks. Female home range areas
were similar for remnants and forest (0.04–0.66 ha). A. flavipes is clearly able to persist in very small patches of native vegetation in the landscape studied here. Its long-term persistence
appears dependent on the ability of females to maintain a presence in the small remnants, and of unrelated males to move between
remnants to breed with resident females. This study illustrates the importance of recognising the occurrence of metapopulations
in fragmented landscapes for conservation management. 相似文献
5.
Corridors are predicted to benefit populations in patchy habitats bypromoting movement, which should increase population densities, gene flow, andrecolonization of extinct patch populations. However, few investigators haveconsidered use of the total landscape, particularly the possibility ofinterpatch movement through matrix habitat, by small mammals. This studycompares home range sizes of 3 species of small mammals, the cotton mouse(Peromyscus gossypinus), old-field mouse (P.polionotus) and cotton rat (Sigmodon hispidus)between patches with and without corridors. The study site was in S. Carolina,USA. Corridor presence did not have astatistically significant influence on average home range size. Habitatspecialization and sex influenced the probability of an individual movingbetween 2 patches without corridors. The results of this study suggest thatsmall mammals may be more capable of interpatch movement without corridors thanis frequently assumed.This revised version was published online in May 2005 with corrections to the Cover Date. 相似文献
6.
A long-term decline of vole populations in boreal Sweden, especially of the grey-sided vole (Clethrionomys rufocanus Sund.), has been revealed by snap-trapping in 1971–2004. We identified important habitats for the grey-sided vole by mapping
the distribution of cumulated number of reproductive females in 1971–1978, prior to the major decline in the 1980s. Mean abundance
of C. rufocanus was higher in the western (inland) than eastern (coastland) part of the study area. As the inland appeared to represent the
most, as far as we know, pristine, abundant part of the population, we based identification of high quality habitats on inland
data only. Four habitats were more important than others and yielded nearly 86% of the reproductive females in spring: (1)
forests of dry, (2) moist and (3) wet/hydric dwarf-shrub type, in addition to (4) forest/swamp complexes rich in dwarf-shrubs.
The latter three habitats were used more frequently than expected from their occurrence in the landscape. Still, the variation
in density of reproductive females within patches of the same habitat was frequently high. This suggested that habitat composition
in the surrounding landscape, perhaps may have affected local vole density at the patch scale. Clear-cut sampling plots appeared
to be low-frequently used by reproductive females, but also by males and immatures. In conclusion, our study indicated the
importance of also studying habitat at a larger scale than that of the patch to get a deeper understanding on how habitat
influences local and regional densities and population dynamics of C. rufocanus. 相似文献
7.
To aid effective conservation and management there is a need to understand the effect of landscape on species ecology. The
aim of this research was to assess the effect of landscape parameters on breeding success of barn owls throughout the Rother
and Arun River catchments, Sussex, UK. We used a Geographic Information System to describe the habitat mosaic and landscape
structure within an estimated home range area of 3 km2 around 85 artificial nest box sites. Results showed that land cover was less heterogeneous at successful sites, with home
ranges dominated by a few habitat types of regular patch shapes. Unsuccessful nesting sites had significantly more improved
grassland, suburban land and wetlands than successful sites. Cluster analysis and Principle Components Analysis was used to
assess the similarity of the habitat mosaic within these areas and pellet analysis was undertaken to assess barn owl diet
and prey availability. Ten prey species were recovered from pellets, field vole (Microtus agrestis), common shrews (Sorex araneus) and house mice (Mus musculus) making up nearly 90% of recoveries. However box sites varied in relative proportions of small mammal, and hence prey availability.
Results indicated that land use and landscape structure can affect breeding success in barn owls. Higher levels of poor quality
small mammal habitat were associated with unsuccessful sites. However, at a landscape scale, the habitat mosaic across the
study area lacked variation, limiting analysis and clear correlations between habitat type and positive breeding success,
suggesting that a finer scale was needed in future studies utilising this approach. 相似文献
8.
Habitat loss is the leading cause of decline in wildlife diversity and abundance throughout the world, but its effects on
wildlife are not always predictable. Matrix population modeling is an increasingly common tool used to predict the effects
of habitat loss. In spite of the growing number of studies using this approach, and its wide use in conservation practice,
the predictions generated by matrix population models are rarely explicitly tested in the field. We compared the ability of
a suite of spatially explicit demographic matrix models to predict the response of white-footed mice to loss of high quality
habitat at mosaic sites in northeast Connecticut, USA. We tested short-term model predictions with landscape scale habitat
perturbation experiments, including clear-cut logging or prescribed burning of high quality habitat at two study sites. Comparison
of each model’s predictions with the observed responses at both sites qualitatively supported predictions that perturbation
of high quality habitat would have negative effects extending into the surrounding landscape. The best-supported model assumed
that evicted residents of the perturbed habitat would successfully resettle in nearby intact habitats, and allowed for gradual
population recovery in the perturbed habitat. Similarly, long-term simulations (20 years) revealed how loss of a single habitat
could trigger population declines throughout a mosaic site. This study shows that careful consideration of model assumptions
such as those pertaining to resettlement behavior is crucial if predictions are to be reliable, and highlights the role of
experiments for comparing alternative model predictions. 相似文献
9.
This study examined the effects of habitat fragmentation on meadow vole (Microtus pennsylvanicus) population dynamics in experimental landscape patches. The study was conducted from May–November 1993 at the Miami University
Ecology Research Center. Eight 0.1-ha small mammal enclosures were used. Four enclosures contained a 160 m2 nonfragmented patch and four enclosures contained four 40 m2 fragmented patches. Thus, each treatment was replicated 4 times in a systematic research design. The patches in both treatments
contained high-quality habitat surrounded by low-quality matrix. Six pairs of adult meadow voles were released in each enclosure
on 27 May 1993. Populations were monitored by live-trapping and radio-telemetry methods. Significantly greater densities of
female voles were found during October in the fragmented treatment compared to the nonfragmented treatment. Also, significantly
more females than males were found in the fragmented treatment compared to the nonfragmented treatment for the total study
period. Significantly more subadult and juvenile males were found in the matrix versus the patch of the nonfragmented treatment
compared to the fragmented treatment. Males in the fragmented treatment had significantly greater mean home range size than
males or females in the nonfragmented treatment. There appears to exist a relationship between patch fragmentation and the
social structure of meadow vole populations; this relationship appears to function as a population regulatory mechanism. 相似文献
10.
The intensively farmed coastal lowland landscape of Germany, adjacent to the North Sea, provides important foraging opportunities
for Black-headed, Common, Herring and Lesser Black-backed gull (Larus ridibundus, L. canus, L. argentatus and L. fuscus). We expected that spatial and temporal utilization of the landscape mosaic as well as behavioural traits and utilization
of food resources would differ between these closely related species, facilitating niche segregation. We recorded habitat
types and their utilization by the four species over a whole year. Furthermore, we related species abundance to several abiotic
parameters. Black-headed and Common gulls were the most numerous species in the study area throughout the year. In general,
the former species preferred bare fields with recently prepared soils and was often associated with tractors in the fields,
whereas the latter species was most often found on pastures. Black-headed gulls seem to have a higher ability to exploit ephemeral,
food sources associated with human activities whereas common gulls prefer habitats with low human activity and with naturally
distributed prey. The most prominent abiotic parameter influencing gull abundance was presence of tractors. Black-headed gulls
have most likely benefited from recent changes in agricultural practice, particularly the increase in cropped land, while
Common gulls may have suffered from a decline in pastures. At present, utilization of the farmland habitat mosaic leads to
niche segregation and supports coexistence, as two of the four gull species mainly forage in the marine environment, while
there is significant habitat partitioning between the other two temporally, spatially and behaviourally. 相似文献
11.
Few relevant data are available to analyze how landscape features affect the abundance and movement patterns of tropical insects.
We used mark-release-recapture techniques to study the effects of landscape structure and composition on habitat preferences
and movements of Canthon cyanellus cyanellus individuals, within a complex tropical deciduous forest landscape in South Mexico during 2004 and 2005. In total, 2,460 individuals
of C. c. cyanellus were captured, including 1,225 females and 1,235 males, out of which 124 individuals (65 females and 59 males) were recaptured
once, and 9 individuals (seven females and two males) were recaptured twice. The abundance of individuals was equally high
in large forest fragments, small forest fragments and hedgerows, but the abundance in pastures was less than half of the abundance
in the other habitat types. To disentangle the movement behaviour of the species from the spatially and temporally varying
sampling effort, we applied a Bayesian state-space modelling framework with a diffusion based movement model. Males showed
generally faster movement rate than females, and they moved faster within forests and hedgerows than within pastures. Contrary
to the assumption of the diffusion model, individuals did not move in a continuous fashion, indicated by the large fraction
of individuals that were recaptured in the site of release. However, the posterior predictive data did not deviate substantially
from the real data in terms of the mean and maximum movement distances recorded, and in terms of the dependence of movement
distance on time between captures. Our results suggest that an important component of the biota in Mexican agro-pasture landscapes
can utilize contemporary landscape elements such as hedgerows or small forest fragments in addition to large fragments of
remnant habitat. These habitats are still locally common in semi-natural ecosystems and require less intensive conservation
management. 相似文献
12.
A large-scale experimental landscape study was conducted to examine the use of corridors and the forest matrix habitat by the hispid cotton rat (Sigmodon hispidus). The role of micro- habitat selection by S. hispidus in influencing routes of movement was also investigated. The experimental landscape consisted of ten 1.64-ha patches (each 128×128 m) established in a loblolly (Pinus teada) forest. Four of the patches were isolated while the other six were connected in pairs by a 32-m wide corridor. Cotton rats (N=96) were simultaneously released into both an isolated and connected patch, and monitored by radiotelemetry for 10 days. We found that the forest matrix was not a barrier to movements of cotton rats. Fifty percent of the cotton rats moved through the matrix. Corridors had no significant effect on the number of animals leaving connected patches (60%) compared to isolated patches (50%). However, corridors were the preferred route to leave a connected patch. Colonization success for cotton rats leaving connected and isolated patches did not significantly differ. Cotton rats exhibited micro-habitat preferences and these preferences differed within patch/corridor and matrix habitats. In patch/corridor habitats, cotton rats selected sites with tall (>1 m) shrubs and high percent cover. In the forest matrix, cotton rats selected sites with abundant cover by vines and low tree canopy cover. Movement patterns of Sigmodon hispidus are not strongly influenced by large-scale landscape spatial structures. Micro-habitat selection, however, does influence movement patterns. These findings have important implications regarding habitat connectivity for small mammals. 相似文献
13.
The population of male Kirtland's warbler (Dendroica kirtlandii) in the breeding season has averaged 206 from 1971 to 1987. The Kirtland's warbler occupies dense jack pine (Pinus banksiana) barrens from 5 to 23 years old and from 1.4 to 5.0 m high, formerly of wildfire origin. In 1984, 73% of the males censused were found in habitat naturally regenerated from wildfire or prescribed burning. The rest were in plantations (11%) or in harvested, unburned jack pine stands stocked by natural regeneration (16%). Twenty-two percent (630 of 2,886) of the Kirtland's warbler males counted in the annual censuses from 1971 through 1984 were found in 26 stands that were unburned and naturally regenerated following harvest. From 1982 to 1987, suitable regenerating areas were barely sufficient to replace currently occupied maturing stands, so population growth was impeded. Ecosystems of suitable size and regeneration characteristics (wildfire and plantation) doubled in area by 1989. In response, the population of Kirtland's warblers increased from 167 to 398 males between 1987 and 1992, but they withdrew almost entirely from the unburned, unplanted barrens by 1989 when the area of more suitable regeneration types increased. Minimum (368 males) and maximum (542 males) population estimates for 1996 were calculated based on 1984 average density (1.9 males per 40 ha) and peak population in burns (2.8 males per 40 ha). 相似文献
14.
15.
To determine how vegetation pattern in early successional forests may be related to plant traits and types of disturbance,
we measured percent cover of individual taxa annually in a South Carolina Pinus elliottii forest, starting one year before, and ending four years after harvest and tree girdling disturbances were applied. The 17
most important taxa surveyed were grouped into four regeneration strategies chosen a priori, and the spatial patterns of these
groups and of the soil were investigated using global variability, semivariograms and kriged maps. We also examined spatial
correlations across years, across taxa, and between species and soil disturbance. Seed bank taxa represented by Dichanthelium spp. increased rapidly and formed large patches, and then quickly declined. Taxa that regenerate by newly dispersed seeds,
represented by Rhus copallina and Rubus spp. occurred at first in a few patches, and became widespread later. Stump sprouters, represented by Quercus spp. and Myrica cerifera, had rapid increases in cover, but their spatial patterns were largely determined by their pre-disturbance patterns. Prunus serotina, which relies on both sprouting and dispersed seed, had moderate cover and a random distribution. Within-species temporal
correlation of spatial pattern was lower in girdled than in harvested plots, and was not clearly related to regeneration strategy.
Forest floor disturbance was patchy and affected the pattern of Dichanthelium spp. in the harvested plots. Negative correlations between herbs and woody plants in harvested plots reflected the role of
biotic (i.e., successional) filters on vegetation pattern. Surprisingly, no spatial correlations were detected between the
nitrogen fixer, Myrica cerifera and other taxa in this N-limited system. In comparing the spatial and temporal patterns, we found kriged maps more informative
than analysis of semivariograms alone. The maps and correlation statistics demonstrated that regeneration traits, spatial
patterns of soil disturbances, and interactions among taxa influence dynamics of the spatial patterns of the plants. We also
demonstrated that disturbance types affected the importance and interactions among these three factors, and caused different
spatial patterns of the plant taxa. 相似文献
16.
Effects of spatial habitat heterogeneity on habitat selection and annual fecundity for a migratory forest songbird 总被引:1,自引:1,他引:0
Understanding how spatial habitat patterns influence abundance and dynamics of animal populations is a primary goal in landscape
ecology. We used an information-theoretic approach to investigate the association between habitat patterns at multiple spatial
scales and demographic patterns for black-throated blue warblers (Dendroica caerulescens) at 20 study sites in west-central Vermont, USA from 2002 to 2005. Sites were characterized by: (1) territory-scale shrub
density, (2) patch-scale shrub density occurring within 25 ha of territories, and (3) landscape-scale habitat patterns occurring
within 5 km radius extents of territories. We considered multiple population parameters including abundance, age ratios, and
annual fecundity. Territory-scale shrub density was most important for determining abundance and age ratios, but landscape-scale
habitat structure strongly influenced reproductive output. Sites with higher territory-scale shrub density had higher abundance,
and were more likely to be occupied by older, more experienced individuals compared to sites with lower shrub density. However,
annual fecundity was higher on sites located in contiguously forested landscapes where shrub density was lower than the fragmented
sites. Further, effects of habitat pattern at one spatial scale depended on habitat conditions at different scales. For example,
abundance increased with increasing territory-scale shrub density, but this effect was much stronger in fragmented landscapes
than in contiguously forested landscapes. These results suggest that habitat pattern at different spatial scales affect demographic
parameters in different ways, and that effects of habitat patterns at one spatial scale depends on habitat conditions at other
scales. 相似文献
17.
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
18.
Movements of bank voles (Clethrionomys glareolus) were studied in a farmland mosaic in Poland. Distances crossed by animals in short-time periods are significantly longer in heterogenous than in homogenous habitats. In long-time and large-spatial scales, a significant portion of the animals in a population travel among habitat elements of the mosaic, reducing the degree of isolation of patch populations and decreasing the probability of local extinction. 相似文献
19.
Despite increasing interest in the ecological effects of urbanization, relatively little is known about its effects in grasslands.
We examined population trends and habitat associations of two predators, the rough-legged hawk (Buteo lagopus) and the red-tailed hawk (B. jamaicensis), in a rapidly urbanizing grassland region at the western edge of the North American Great Plains. Count data indicate that
rough-legged hawk populations declined in the area by nearly 75% between 1971 and 2003, at the same time that numbers of red-tailed
hawks more than tripled. These changes were not part of wider regional trends, nor were they buffered by development of an
open space system in one of the urbanizing counties. While the human population grew steadily over the 33-year period, hawk
numbers did not begin to change significantly until the early 1980s, suggesting landscape threshold responses to development.
Rough-legged hawks remaining in the area between 1999 and 2002 avoided human settlements and hunted in places with tracts
of treeless grassland. In contrast, red-tailed hawks selected relatively tall perches in trees or on utility poles from which
to hunt, in areas closer to buildings and roads than randomly selected plots, and remained abundant in the mosaic of developed
and rural agricultural lands. The failure of the grassland open space system to sustain the rough-legged hawk, and other bird
species characteristic of treeless open prairie, illustrates the challenges of conserving fauna with apparent hypersensitivity
to the three-dimensional habitat complexity that accompanies even modest amounts of development. 相似文献
20.
Aafke M. Schipper Kees Koffijberg Marije van Weperen Guido Atsma Ad M. J. Ragas A. Jan Hendriks Rob S. E. W. Leuven 《Landscape Ecology》2011,26(3):397-410
Understanding the driving forces behind the distribution of threatened species is critical to set priorities for conservation
measures and spatial planning. We examined the distribution of a globally threatened bird, the corncrake (Crex crex), in the lowland floodplains of the Rhine River, which provide an important breeding habitat for the species. We related
corncrake distribution to landscape characteristics (area, shape, texture, diversity) at three spatial scales: distinct floodplain
units (“floodplain scale”), circular zones around individual observations (“home range scale”), and individual patches (“patch
scale”) using logistic regression. Potential intrinsic spatial patterns in the corncrake data were accounted for by including
geographic coordinates and an autocovariate as predictors in the regression analysis. The autocovariate was the most important
predictor of corncrake occurrence, probably reflecting the strong conspecific attraction that is characteristic of the species.
Significant landscape predictors mainly pertained to area characteristics at the patch scale and the home range scale; the
probability of corncrake occurrence increased with potential habitat area, patch area, and nature reserve area. The median
potential habitat patch size associated with corncrake occurrence was 11.3 ha; 90% of the corncrake records were associated
with patches at least 2.2 ha in size. These results indicate that the corncrake is an area-sensitive species, possibly governed
by the males’ tendency to reside near other males while maintaining distinct territories. Our results imply that corncrake
habitat conservation schemes should focus on the preservation of sufficient potential habitat area and that existing management
measures, like delayed mowing, should be implemented in relatively large, preferably contiguous areas. 相似文献