共查询到20条相似文献,搜索用时 31 毫秒
1.
Susan Romero James F. Campbell James R. Nechols Kimberly A. With 《Landscape Ecology》2009,24(1):39-51
Landscape structure can influence the fine-scale movement behavior of dispersing animals, which ultimately may influence ecological
patterns and processes at broader scales. Functional grain refers to the finest scale at which an organism responds to spatial
heterogeneity among patches and extends to the limits of its perceptual range. To determine the functional grain of a model
insect, red flour beetle (Tribolium castaneum), we examined its movement behavior in response to experimental flour landscapes. Landscape structure was varied by manipulating
habitat abundance (0%, 10%, 30%, and 100%) and grain size of patches (fine-2 × 2 cm, intermediate-5 × 5 cm, and coarse-10 × 10 cm)
in 50 × 50 cm landscapes. Pathway metrics indicated that beetles used a similar proportion of all landscape types. Several
pathway metrics indicated a graded response from the fine to the coarse grain landscape. Lacunarity analysis of beetle pathways
indicated a non-linear change in space use between the fine and intermediate landscapes and the coarse-grained landscape.
Beetles moved more slowly and tortuously (with many turns), and remained longer in both the overall landscape and individual
patches, in fine-grained compared to coarse-grained landscapes. Our research demonstrates how detailed examination of movement
pathways and measures of lacunarity can be useful in determining functional grain. Spatially explicit, organism-centered studies
focusing on behavioral responses to different habitat configurations can serve as an important first step to identify behavioral
rules of movement that may ultimately lead to more accurate predictions of space use in landscapes. 相似文献
2.
Birds can serve as useful model organisms to investigate community level consequences of forestry practices. In this study
we investigated the relationships between wintering bird communities and habitat and landscape characteristics of lowland
managed forests in Northern Italy. This area is characterized by the spread of the black locust, an alien species that has
been favored by forestry practices at the expense of natural oak forests. Birds were censused in winter by point counts in
randomly selected plots of 50 m radius. We first addressed bird community–habitat relationships by means of habitat structure
measurements, then we investigated bird community–landscape relationships by using GIS techniques. We used generalized linear
models (GLM) to test for the effects of habitat and landscape variables on bird community parameters (namely bird species
richness, diversity and abundance). Bird community parameters were influenced by oak biomass and tree age, and by oak area
and core area, while the other forest habitat types showed less influence. In forest management terms, the main conclusion
is that the retention of native oaks is the keyfactor for the conservation of winter bird diversity in local deciduous woods.
At the habitat level black locust harvesting may be tolerated, provided that old, large, native oaks are retained in all local
woodlots to preserve landscape connectivity and foraging resources. At the landscape meso-scale, large native oak patches,
should be preserved or, where necessary, restored.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
3.
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
4.
Identification of functional corridors with movement characteristics of brown bears on the Kenai Peninsula,Alaska 总被引:2,自引:1,他引:2
Tabitha A. Graves Sean Farley Michael I. Goldstein Christopher Servheen 《Landscape Ecology》2007,22(5):765-772
We identified primary habitat and functional corridors across a landscape using Global Positioning System (GPS) collar locations
of brown bears (Ursus arctos). After deriving density, speed, and angular deviation of movement, we classified landscape function for a group of animals
with a cluster analysis. We described areas with high amounts of sinuous movement as primary habitat patches and areas with
high amounts of very directional, fast movement as highly functional bear corridors. The time between bear locations and scale
of analysis influenced the number and size of corridors identified. Bear locations should be collected at intervals ≤6 h to
correctly identify travel corridors. Our corridor identification technique will help managers move beyond the theoretical
discussion of corridors and linkage zones to active management of landscape features that will preserve connectivity. 相似文献
5.
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
6.
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
7.
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
8.
Wildfires and post-fire logging and planting have a lasting influence on the quantity and arrangement of live and dead vegetation,
which can, in turn, affect the behavior of future fires. In 2002, the Biscuit Fire re-burned 38,000 ha of mixed-conifer/evergreen
hardwood forest in southwestern Oregon that had burned heterogeneously during the 1987 Silver Fire and then was subject, in
part, to post-fire logging and planting. We measured vegetation cover and crown damage from at temporal sequence (1987, 2000,
and 2002) of digital aerial photo-plots (plot size = 6.25 ha) within managed and unmanaged portions of the twice-burned landscape.
We estimated the strength and nature of relationships between crown damage in the two fires while also accounting for the
influence of several vegetation, topographic, weather, and management variables. On average, unmanaged plots within the reburn
area had 58% of their live crown cover scorched or consumed by the Biscuit Fire (median = 64%). The level of re-burn crown
damage was strongly related to the level of crown damage during the Silver Fire. Typically, the areas that burned severely
in the Silver Fire succeeded to a mix of shrubs and tree regeneration (i.e. shrub-stratum vegetation), which then experienced
high levels of Biscuit Fire damage. In contrast, the level of tree-stratum damage in the Biscuit Fire was largely independent
of Silver Fire damage. Within plots that were salvage-logged then planted after the Silver Fire, on average 98% of the vegetation
cover was damaged by the Biscuit Fire (median = 100%). Within the plots that experienced complete crown damage in the Silver
Fire but were left unmanaged, on average 91% of the vegetation cover was damaged by the Biscuit Fire (median = 95%). Our findings
suggest that in productive fire-prone landscapes, a post-fire mosaic of young regenerating vegetation can influence the pattern
of crown damage in future wildfires. 相似文献
9.
Rebecca Lange Tim Diekötter Lisa A. Schiffmann Volkmar Wolters Walter Durka 《Landscape Ecology》2012,27(3):381-392
Unlike rare or specialised species, widespread abundant species have often been neglected when studying effects of habitat
fragmentation. However, recently, it was shown that in the widespread abundant bush cricket Pholidoptera griseoaptera gene flow becomes restricted when the share of suitable habitat dropped below a threshold of 20% at the landscape scale.
Here, using the same highly fragmented landscape, we studied the impact of habitat configuration and matrix quality on genetic
variation and population differentiation of P. griseoaptera at a small spatial scale. We investigated four clusters of three populations that were either disconnected or connected and
had either low quality (arable land) or high quality (grassland) matrix. The number of alleles was significantly lower in
disconnected than in connected clusters, irrespective of matrix quality. Genetic differentiation was equally high in the two
disconnected clusters and in the connected cluster with low quality matrix (G
ST ≥ 0.030; D ≥ 0.082), whereas it was significantly reduced when connected habitats were embedded in a high quality grassland matrix (G
ST = 0.004; D = 0.011). Analyses of least-cost paths showed that grassy landscape elements in fact represent high quality matrix, but that
linear grassy margins are costly for dispersal. The effect of habitat configuration on genetic diversity may be explained
by lower effective population sizes in disconnected habitats. The fact that only the connected populations in high quality
matrix were not differentiated indicates that landscape management should simultaneously consider habitat configuration and
matrix quality to effectively promote small and dispersal-limited species, also at small spatial scales. 相似文献
10.
We developed a spatially-explicit gap dynamics simulation model to evaluate the effects of disturbances at the scale of a landscape for a semiarid grassland in northcentral Colorado, USA. The model simulates the establishment, growth, and death of individual plants on a small plot through time at an annual time step. Long-term successional dynamics on individual plots (single gaps) and on a landscape composed of a grid of plots were evaluated. Landscapes were simulated as either a collection of independent plots or as a collection of interacting plots where processes on one plot were influenced by processes on adjacent plots. Because we were interested in the recovery of the dominant plant species, the perennial grass blue grama (Bouteloua gracilis (H.B.K.) Lag. ex Griffiths) after disturbances, we focused on scale-dependent processes, such as seed dispersal, that are important to the recruitment of individuals of B. gracilis.
The type of simulated landscape was important to the recovery time of B. gracilis after a disturbance. Landscapes composed of independent plots recovered more rapidly following a disturbance than landscapes composed of interacting plots in which the recovery time was dependent on the spatial scale of the disturbance. 相似文献
11.
Previous comparative studies on patterns of reproduction in small-mammal species focus primarily on latitudinal differences
in average litter size. Few studies compare reproductive patterns among northern and southern populations at the landscape
scale. Our study compares differences in seasonal patterns of reproduction in northern and southern populations of the golden
mouse, Ochrotomys nuttalli, and the white-footed mouse, Peromyscus leucopus. These are remarkably similar species with regard to bioenergetics, body mass, feeding behavior, home-range size, natural
history, nest-site preference, and periods of activity. Both species also exhibit very similar intraspecific seasonal patterns
of reproduction across their respective geographic ranges. We found that O. nuttalli and P. leucopus switch from a summer breeding season, extending from late spring through early autumn in the north to a winter breeding season
extending from late autumn through early spring in the south, near the isotherm where mean annual temperature is 15.6°C (60°F),
or approximately 35° N latitude. This latitudinal isotherm provides a geographic benchmark to address future changes in patterns
of reproduction attributed to climate change. Findings also suggest that length of the breeding season and patterns of reproduction
between species partially explain why P. leucopus is typically more abundant than O. nuttalli in similar habitat types. 相似文献
12.
Zharikov et al. (2006: Landscape Ecology 21:107–120) modeled the nest-site habitat use of marbled murrelets (Brachyramphus marmoratus) in Desolation Sound (DS) and Clayoquot Sound (CS), British Columbia. They compared known nest sites, located with radio-telemetry,
with randomly-located points within the same areas. Their conclusions suggest that murrelets tended to nest in disproportionately
smaller fragments within the more disturbed DS landscape; streams, steeper slopes, and lower elevations were selected in both
landscapes; murrelets nested closer to recent clearcuts than would be expected in the DS landscape; and survivorship of nestlings
was greater in areas with recent clearcuts and was positively correlated with recent habitat fragmentation. These conclusions
are contrary to current management guidelines in British Columbia, and therefore require close scrutiny. Our detailed examination
reveals flaws in their use of data, application of modeling, and most seriously, interpretation of the results. Problems include:
conceptual errors in the interpretation of models; inappropriate spatial resolution; confusing use and interpretation of fragmentation
and patch size data; overemphasis of statistically significant but biologically trivial results; and ignoring some contradictory
studies. We conclude that it would be risky to apply the results from Zharikov et al. in the selection of murrelet nesting
habitat for management purposes in British Columbia. Our review identifies issues that may arise in other ecological modeling
studies and stresses the need for biological realism in addition to statistical rigour. 相似文献
13.
Widespread adoption of genetically modified glyphosate-resistant (GR) crops in the US has dramatically changed the agricultural
landscape to one that selects for establishment and spread of weedy species resistant to glyphosate, a commonly applied herbicide.
Weed species that possess the means to readily spread across the landscape will be contained by weed management strategies
that limit weed establishment and prevent seed set. An empirically-derived simulation model was developed to explore GR Conyza canadensis spread in relation to characteristics of the agricultural landscape. C. canadensis seeds are carried in the wind and move among fields and therefore, access high quality habitat (GR crops) at long distances.
The baseline scenario was the current GR adoption levels in many US agricultural landscapes with corn and soybean rotated
annually. Alternate scenarios examined the interacting effects of management uniformity (GR crop adoption) and increased landscape
richness (three crops: corn, soybean, alfalfa, instead of two), over a 10 year simulation period. When landscape uniformity
increased (increased GR corn adoption), 3× more fields would be infested with the resistant biotype and a specific field would
have up to 24% greater likelihood of being infested compared to the current GR crop adoption levels. Increased landscape richness
(adding alfalfa as a third crop) slightly decreased GR C. canadensis abundance. Reduced GR management uniformity by way of reducing GR soybeans to half their current adoption levels had the
greatest impact on spread and prevented GR C. canadensis from reaching high abundance. Large-scale reliance on glyphosate for weed management has increased high-fitness habitat and
will result in rapid spread of glyphosate-resistant weeds. Without significant reductions of glyphosate use and without spatial
coordination of weed and crop management practices, GR weeds will continue to spread rapidly and impact agricultural practices
in areas reliant on glyphosate. 相似文献
14.
Felicia Pereoglou Christopher MacGregor Sam C. Banks Jeff Wood Fred Ford David B. Lindenmayer 《Landscape Ecology》2016,31(2):255-269
Context
Multiple ecological drivers generate spatial patterns in species’ distributions. Changes to natural disturbance regimes can place early successional habitat specialists at an increased risk of extinction by altering landscape patterns of habitat suitability.Objectives
We developed a series of hypotheses to evaluate the effects of landscape structure, fire history, and site-level habitat quality on site occupancy by an early successional specialist, the eastern chestnut mouse (Pseudomys gracilicaudatus).Methods
We obtained eight years of monitoring data from 26 sites in recently burned heathland in southeast Australia. We used generalised linear models to determine which explanatory variables were related to occupancy. We also explored predictability in patterns of small mammal species co-occurrence.Results
Landscape structure (patch area, landscape heterogeneity) was strongly related to site occupancy. Site occupancy was associated with dead shrubs in the understory and rock cover on ground layer, but was not directly influenced by recent or historical fire. Contrary to contemporary ecological theory, we found no predictable species associations in our early successional community.Conclusions
We recommend surveys take account of landscape configuration and proximity to suitable habitat for optimal results. Fire regimes expected to promote eastern chestnut mouse population growth should encourage the retention of critical habitat features rather than be based on temporal rates of successional stages. For management to adequately account for post-disturbance patterns in early successional communities, a species-by-species, multi-scaled approach to research is necessary.15.
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
16.
Importance of Wetland Landscape Structure to Shorebirds Wintering in an Agricultural Valley 总被引:2,自引:1,他引:2
Only recently has the influence of landscape structure on habitat use been a research focus in wetland systems. During non-breeding
periods when food can be locally limited, wetland spatial pattern across a landscape may be of great importance in determining
wetland use. We studied the influence of landscape structure on abundances of wintering Dunlin (Calidris alpina) and Killdeer (Charadrius vociferus) observed on wetlands in the agricultural Willamette Valley of Oregon, USA, during two winters (1999–2000, 2000–2001) of
differing rainfall. We examined (1) shorebird use within a sample of 100 km2 regions differing in landscape structure (hectares of shorebird habitat [wet, unvegetated]) and (2) use of sites differing
in landscape context (area of shorebird habitat within a species-defined radius). For use of sites, we also assessed the influence
of two local characteristics: percent of soil exposed and area of wet habitat. We analyzed data using linear regression and
information-theoretic modeling. During the dry winter (2000–2001), Dunlin were attracted to regions with more wetland habitat
and their abundances at sites increased with greater area of shorebird habitat within both the site and the surrounding landscape.
In contrast, Dunlin abundances at sites were related to availability of habitat at only a local scale during the wet winter
(1999–2000). Regional habitat availability was of little importance in predicting Killdeer distributions, and Killdeer site
use appeared unrelated to habitat distributions at both landscape and local scales. Results suggest prioritizing sites for
conservation that are located in areas with high wetland coverage. 相似文献
17.
Fine-scale landscape change can alter dispersal patterns of animals, thus influencing connectivity or gene flow within a population.
Furthermore, dispersal patterns of different species may be influenced by the landscape in varying ways. Our research first
aimed to examine whether the spatial genetic structure within populations of closely related bird species differs in response
to the same landscape. Second, we examined whether individual-level movement characteristics are a mechanistic driver of these
differences. We generated a priori predictions of how landscape features will influence dispersal (particularly the response
of individuals to habitat boundaries both natural and human-induced) based on a movement model developed by Fahrig (Funct
Ecol 21:1003–1015, 2007). This model allowed us to predict genetic relatedness patterns in populations of two passerine bird species with different
life-history traits from Queensland, Australia (yellow-throated scrubwren Sericornis citreogularis, a habitat specialist; white-browed scrubwren Sericornis frontalis, a habitat generalist). We quantified our predictions using cost-distance modelling and compared these to observed pairwise
genetic distances (a
r
) between individuals as calculated from microsatellite markers. Mantel tests showed that our a priori models correlated with
genetic distance. Euclidean distance was most closely correlated to genetic distance for the generalist species (r = 0.093, P = 0.002), and landscape models that included the avoidance of unsuitable habitat were best for the specialist species (r = 0.107, P = 0.001). Our study showed that predictable movement characteristics may be the mechanism driving differences in genetic
relatedness patterns within populations of different bird species. 相似文献
18.
Robert A. Long Therese M. Donovan Paula MacKay William J. Zielinski Jeffrey S. Buzas 《Landscape Ecology》2011,26(3):327-340
Terrestrial carnivores typically have large home ranges and exist at low population densities, thus presenting challenges
to wildlife researchers. We employed multiple, noninvasive survey methods—scat detection dogs, remote cameras, and hair snares—to
collect detection–nondetection data for elusive American black bears (Ursus americanus), fishers (Martes pennanti), and bobcats (Lynx rufus) throughout the rugged Vermont landscape. We analyzed these data using occupancy modeling that explicitly incorporated detectability
as well as habitat and landscape variables. For black bears, percentage of forested land within 5 km of survey sites was an
important positive predictor of occupancy, and percentage of human developed land within 5 km was a negative predictor. Although
the relationship was less clear for bobcats, occupancy appeared positively related to the percentage of both mixed forest
and forested wetland habitat within 1 km of survey sites. The relationship between specific covariates and fisher occupancy
was unclear, with no specific habitat or landscape variables directly related to occupancy. For all species, we used model
averaging to predict occurrence across the study area. Receiver operating characteristic (ROC) analyses of our black bear
and fisher models suggested that occupancy modeling efforts with data from noninvasive surveys could be useful for carnivore
conservation and management, as they provide insights into habitat use at the regional and landscape scale without requiring
capture or direct observation of study species. 相似文献
19.
In the North American upper Great Lakes region, forests dominated by the aspens (Populus grandidentata Michx. – bigtooth aspen, and P. tremuloides Michx. – trembling aspen), which established after late 19th and early 20th century logging, are maturing and succession
will create a new forest composition at landscape to regional scales. This study analyzed the capabilities of Landsat ETM+
remote sensing data combined with existing ecological land unit classifications to discriminate and quantify patterns of succession
at the landscape scale over the 4200 ha University of Michigan Biological Station (UMBS) in northern Lower Michigan. In a
hierarchical approach first multi-temporal Landsat ETM+ was used with a landscape ecosystem classification to map upland forest
cover types (overall accuracy 91.7%). Next the aspen cover type was subset and successional pathways were mapped within that
type (overall accuracy 89.8%). Results demonstrated that Landsat ETM+ may be useful for these purposes; stratification of
upland from wetland types using an ecological land unit classification eliminated confounding issues; multi-temporal methods
discriminated evergreen conifer versus deciduous understories. The Landsat ETM+ classifications were then used to quantify
succession and its relationship to landform-level ecological land units. Forests on moraine and ice contact landforms are
succeeding distinctly to northern hardwoods (95% and 88% respectively); those on outwash and other landforms show greater
diversity of successional pathways. 相似文献
20.