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1.
Conservation planning at broad spatial scales facilitates coherence between local land management and objectives set at the state or provincial level. Habitat suitability models are commonly used to identify key areas for conservation planning. The challenge is that habitat suitability models are data hungry, which limits their applicability to species for which detailed information exists, but managers need to address the needs of all at-risk species. We propose a modeling approach useful for regional-scale conservation planning that accommodates limited species knowledge, and identifies what managers should aim for at the local scale. For twenty at-risk bird species, we built models to identify potential habitat using both literature information and empirical data. Species occupancy within potential habitat depends on the presence of intrinsic elements, which we identified for each species so that managers can enhance these elements as appropriate. For most species, the estimated amount of habitat needed to meet population targets was <10% of the mapped potential habitat, with notable exceptions for Northern Goshawk (Accipiter gentilis; 100%), Brown Thrasher (Toxostoma rufum; 63.7%), and Veery (Catharus fuscescens; 17.9%). Model validation showed that interior forest species models performed best. Our modeling framework allowed us to build potential habitat models to various endpoints for different species, depending on the information available, and revealed a number of species for which basic natural history data are missing. Our potential habitat models provide regional perspective and guide local habitat management, and assist in identifying research priorities. 相似文献
2.
Paolo Pedrini 《Biological conservation》2002,103(2):163-172
We compared the density of golden eagles (Aquila chrysaetos) and their nest dispersion, productivity and diet in Alpine and pre-Alpine areas. The comparison was made at two spatial scales: (1) at the territory level within two contiguous populations, and (2) at the population level, using published data for 22 populations scattered across four countries (France, Switzerland, Germany and Italy). Availability of golden eagle's main prey species was higher in Alpine than in pre-Alpine regions. The potential foraging ranges of pairs of eagles in the pre-Alps had larger amounts of woodland and lower amounts of suitable foraging habitat than those of Alpine pairs. At both spatial scales, density and productivity were lower in the pre-Alps. Also, pre-Alpine populations were characterised by a lower percentage of main prey species in the diet, which was significantly correlated with productivity, and by a higher breadth of diet, which was negatively correlated with density. Overall, higher prey availability and habitat suitability in the Alps resulted in higher density and breeding success, in a manner compatible with theoretical metapopulation models. We suggest that priority be given to conservation of eagle populations in high quality Alpine habitat, and that conservation action be carried out by a mixture of site-protection measures and conservation of the wider environment. 相似文献
3.
Linking habitat suitability and seed dispersal models in order to analyse the effectiveness of hydrological fen restoration strategies 总被引：1，自引：0，他引：1
A.H. van Loon H. Soomers P.P. Schot M.F.P. Bierkens J. Griffioen M.J. Wassen 《Biological conservation》2011,(3):1025-1035
The effectiveness of measures targeted at the restoration of populations of endangered species in anthropogenically dominated regions is often limited by a combination of insufficient restoration of habitat quality and dispersal failure. Therefore, the joint prediction of suitable habitat and seed dispersal in dependency of management actions is required for effective nature management. Here we demonstrate an approach, which links a habitat suitability and a seed dispersal model. The linked model describes potential species distribution as a function of current species distribution, species-specific dispersal traits, the number of successful dispersal events, dispersal infrastructure and habitat configuration. The last two variables were related to water management actions. We demonstrate the applicability of the model in a strategy analysis of hydrological restoration measures for a large fen area in which still numerous endangered plant species grow.With the aid of the linked model, we were able to optimise the spatial planning of restoration measures, taking into account both the constraints of water management practices on abiotic restoration and the effects of habitat fragmentation on dispersal. Moreover, we could demonstrate that stand-alone habitat suitability models, which assume unlimited dispersal, may considerably overestimate restoration prospects. For these reasons, we conclude that linked habitat suitability and dispersal models can provide useful insights into spatially differentiated potentials and constraints of nature restoration measures targeted at the sustainable conservation of endangered plant populations whose habitats have been deteriorated due to undesirable effects of land and water management on abiotic conditions. These insights may contribute to the design of cost-effective nature restoration and conservation measures. 相似文献
4.
Carabus variolosus is a highly endangered insect which is listed in the EC Habitats and Species Directive. Detailed knowledge of the habitat requirements of this semi-aquatic woodland carabid beetle is needed if effective conservation and management strategies are to be developed. Previous habitat models have proved to be a successful analytical and predictive tool for the conservation of species. We conducted an intensive study over a two year period on two extant C. variolosus populations in Westphalia (Germany) using live capture pitfall traps. We analysed the distribution of the beetles over their main activity period in relation to a large number of edaphic and vegetation variables in order to estimate habitat suitability models and describe optimum ranges. C. variolosus is restricted to the fringes of water bodies and to areas of high soil moisture that display patches of bare soil, shows a slight preference for sparse tree vegetation, and avoids acidic soil. Temporal and spatial transferability of the statistically significant habitat models indicates their robustness and validity. Based on the results of our study, we suggest management measures for the conservation of C. variolosus, which promote the rehabilitation of natural flood plains of headwater areas. 相似文献
5.
Although spatial scale is important for understanding ecological processes and guiding conservation planning, studies combining a range of scales are rare. Habitat suitability modelling has been used traditionally to study broad-scale patterns of species distribution but can also be applied to address conservation needs at finer scales. We studied the ability of presence-only species distribution modelling to predict patterns of habitat selection at broad and fine spatial scales for one of the rarest mammals in the UK, the grey long-eared bat (Plecotus austriacus). Models were constructed with Maxent using broad-scale distribution data from across the UK (excluding Northern Ireland) and fine-scale radio-tracking data from bats at one colony. Fine-scale model predictions were evaluated with radio-tracking locations from bats from a distant colony, and compared with results of traditional radio-tracking data analysis methods (compositional analysis of habitat selection). Broad-scale models indicated that winter temperature, summer precipitation and land cover were the most important variables limiting the distribution of the grey long-eared bat in the UK. Fine-scale models predicted that proximity to unimproved grasslands and distance to suburban areas determine foraging habitat suitability around maternity colonies, while compositional analysis also identified unimproved grasslands as the most preferred foraging habitat type. This strong association with unimproved lowland grasslands highlights the potential importance of changes in agricultural practices in the past century for wildlife conservation. Hence, multi-scale models offer an important tool for identifying conservation requirements at the fine landscape level that can guide national-level conservation management practices. 相似文献
6.
In recent years, predictive habitat distribution models, derived by combining multivariate statistical analyses with Geographic Information System (GIS) technology, have been recognised for their utility in conservation planning. The size and spatial arrangement of suitable habitat can influence the long-term persistence of some faunal species. In southwestern Victoria, Australia, populations of the rare swamp antechinus (Antechinus minimus maritimus) are threatened by further fragmentation of suitable habitat. In the current study, a spatially explicit habitat suitability model was developed for A. minimus that incorporated a measure of vegetation structure. Models were generated using logistic regression with species presence or absence as the dependent variable and landscape variables, extracted from both GIS data layers and multi-spectral digital imagery, as the predictors. The most parsimonious model, based on the Akaike Information Criterion, was spatially extrapolated in the GIS. Probability of species presence was used as an index of habitat suitability. A negative association between A. minimus presence and both elevation and habitat complexity was evidenced, suggesting a preference for relatively low altitudes and a vegetation structure of low vertical complexity. The predictive performance of the selected model was shown to be high (91%), indicating a good fit of the model to the data. The proportion of the study area predicted as suitable habitat for A. minimus (Probability of occurrence ?0.5) was 11.7%. Habitat suitability maps not only provide baseline information about the spatial arrangement of potentially suitable habitat for a species, but they also help to refine the search for other populations, making them an important conservation tool. 相似文献
7.
In North Africa, and especially in the Sahara Desert, biodiversity is poorly known. Of the five widespread canid species present, one is Data Deficient, three are considered widespread although habitat selection could limit their area of occupancy, and distribution maps available are coarse for conservation planning. This study identifies biogeographic patterns in North-African canids through the combination of high resolution presence data with 16 environmental factors. Predictive models trained in north-west Africa are projected to all North Africa. canids exhibited distinct biogeographical affinities. GIS tools and Maximum Entropy models identify a mixture of climatic and habitat factors as main predictors of species occurrence. Suitable habitats for North-African canids are mostly fragmented: probable occurrence was identified for Canis aureus in Saharan peripheral regions and mountains, for Vulpes pallida in a narrow band along the Sahel and in southern Saharan mountains, for Vulpes rueppellii throughout the Sahara, for Vulpes vulpes in northern Africa until the Sahara northern limit, and for Vulpes zerda in almost all Sahara. Areas of potential sympatry between species with similar niches and parapatric ranges are identified along relatively narrow bands. The small pixel size of projections allows the identification of suitable refuges for species otherwise absent in the driest Saharan habitats, providing framework data for the definition of the global conservation status of V. pallida, and conservation strategies for the guild. The biological value of Saharan mountains is emphasised as they constitute isolated suitable areas. Ecological-niche based models should be developed for other endangered Saharan vertebrates. 相似文献
8.
Cameron W. Barrows Kristine L. Preston Michael F. Allen 《Biological conservation》2008,141(7):1885-1893
Estimating historic distributions of species is a critical step in evaluating current levels of habitat loss, evaluating sites for potential restoration and reintroductions, and for conservation planning at a landscape scale. However historic distributions can be difficult to estimate objectively because substantial habitat changes may have occurred prior to comprehensive surveys. As a means to address this question, we evaluated a novel approach by creating spatial niche models for two species of psammophilic lizards. Using a partitioned Mahalanobis D2 analysis and abiotic variables that were independent of anthropogenic change, we created niche models for the federally threatened Coachella Valley fringe-toed lizard (Uma inornata) and for the flat-tailed horned lizard (Phrynosoma mcallii). The niche models estimated that within the Coachella Valley there were originally 32,164 ha of potential habitat for the fringe-toed lizard and 33,502 ha of potential habitat for the horned lizard. After screening these estimates of historic habitat for current conditions that would render that potential habitat unsuitable, we calculated a 91-95% loss of potential habitat for the fringe-toed lizard and an 83-92% loss for the horned lizard. Unlike the fringe-toed lizard, the horned lizard also occurs outside the Coachella Valley. Conducting a similar analysis throughout its range would provide an objective estimate of the total habitat loss experienced by this species. This information could be used to address whether granting it federal or state protection is warranted. For species whose distributions can be modeled with abiotic variables such as soils, elevation, topography, and climate, this approach may have broad applications for resolving questions regarding their current levels of habitat loss and regional conservation planning. 相似文献
9.
The appropriateness of using carrying capacity (CC) estimates to indicate habitat utilisation for a particular species, and thus as a tool for conservation population planning, has been questioned. We argue individual fitness is driven by resource availability, and we therefore assume individuals select habitats with a higher quality, abundance, and availability of key resources. In the past such selection has been related to the CC of a habitat. We tested whether we can use CC estimates to indicate habitat selection by individuals using a selective forager, black rhinoceros Diceros bicornis, for which CC approaches underpin species conservation plans. We tested for correlation of individuals’ habitat selection with predicted CC values at three spatial scales of selection. Individual selection was not related to the value of the habitat according to our CC estimates for any of the three scales we tested at. We discuss how density-dependence, environmental variables, scale of selection, individual variation and intra- and inter-specific dynamics may have influenced these results. Following this, we question the use of a priori calculations of potential resource quality and abundance of habitats (CC estimates), which do not take into account the various factors that influence an animal’s selection of a habitat, as an indicator of species habitat selection. We raise caution regarding the use of such CC models to determine optimal population numbers for an area. 相似文献
10.
Theory suggests that a disproportionate loss of species occurs when total habitat cover decreases to 10-30% of the landscape. To date, little empirical evidence has been collected to test for such thresholds in habitat cover, especially at the landscape scale. Here, we present empirical data on the species richness of woodland-dependent birds collected systematically from 24 landscapes (each 100 km2) that sample a gradient in habitat cover from <2% to 60%. To compare the relative effects of habitat cover and habitat configuration, landscapes with similar amounts of habitat but contrasting configuration (i.e., aggregated versus dispersed) were surveyed and the richness of woodland-dependent birds collated for each landscape. The relationship between species richness, habitat cover and habitat configuration was examined using analysis of co-variance (ANCOVA), multiple linear regression and univariate non-linear modelling. There was a significant effect of habitat cover (co-variate) in the ANCOVA, but the main treatment effect of configuration was not significant. However, comparison of non-linear models indicated that the shape of the response curve of species loss with decreasing habitat cover differed between aggregated and dispersed landscapes. Species richness was significantly related to habitat cover in all analyses, explaining between 55% and 60% of the variance in regression models. Mean patch shape complexity and the extent of habitat aggregation were also significant explanatory variables, but explained less than 10% of the variance in richness of woodland birds. Biogeographic variables (range in elevation and geographic location) explained up to 14% of the variance in species richness. There was strong evidence for a threshold response in species richness: non-linear models (broken-stick, exponential, inverse) exhibiting a sharp decline in species richness in landscapes with less than 10% habitat cover provided a better fit to the observed data than linear models. To our knowledge, this is the first empirical demonstration of landscape-level thresholds in species richness. We emphasise that thresholds in species richness denote multiple species’ extinction events, the end point of the process of species decline. For viable populations, habitat cover must be maintained well above the threshold level. Finally, thresholds of assemblage measures, such as species richness, potentially mask compositional changes in the avifauna community and may also conceal the loss of species with greater sensitivity to landscape change. 相似文献
11.
植被生态系统的恢复越来越多地受到全球各界关注,潜在自然植被(potential natural vegetation, PNV)和生境适宜性概念应纳入植被规划,作为植被恢复的参考依据。基于高空间分辨率气候数据,使用动态植被模型(LPJ-GUESS),揭示黄土高原2001—2020年PNV空间格局及其生境适宜性的动态演变,并界定了植被优先恢复区。结果表明:黄土高原的PNV以草地和森林为主,潜在草地主要集中在北部、西北部地区(约占73.23%),潜在森林主要分布在南部地区(约占26.16%),极少的裸地主要分布在西部高海拔山区;在潜在森林中,温带落叶阔叶林、寒温性常绿针叶林、温带常绿针叶林占比分别为22.28%,3.88%,0.01%;随着气候变化的推进,潜在森林面积有所下降,而潜在草地面积有些许增加。PNV的生境适宜性呈现西北低、南部及东南高的分布,其中,分布在黄土高原南部平原地带的潜在温带落叶阔叶林其生境适宜性较高,而分布在北部及东北部的潜在草地其生境适宜性较低;并且,对于每种PNV类型,其最高生境适宜性所占据的地理空间及优先恢复区有较大差异。研究结果可为黄土高原植被恢复重建提供科学依据。 相似文献
12.
Saproxylic insects are characterised by their exceptional diversity and high proportion of threatened species. No recent studies have demonstrated the validity of habitat suitability analysis for scientifically based habitat management for these species. We studied the habitat requirements of the endangered longhorn beetle Cerambyx cerdo, a species with a supposed keystone function for the saproxylic insect community living on oaks. We used species distribution modelling based on datasets from Central Europe to understand the species-habitat relationships and to find the environmental variables responsible for habitat selection of C. cerdo. Our results show that the most important parameters, insolation, presence of oak sap, bark depth and the distance from the next colonised tree, are able to predict the presence of C. cerdo very well. A spatial validation procedure revealed very similar predictive power, indicating the general validity of our model. Tree-level parameters were shown to have a stronger effect on the occurrence probability than landscape-level predictors. To improve the tree-level conditions (e.g. insolation on the trunk) habitat management in the form of semi-open pasture landscapes is recommended from which many other taxa will also draw considerable benefit. The provision of such conditions over decades is the essential key in the conservation of this longhorn beetle species. The success of the European network of conservation areas “Natura 2000” heavily depends on broad biological knowledge of the designated protected species. The present paper shows that species distribution models can give valuable contributions for conservation in saproxylic insects. 相似文献
13.
The Mallee Emu-wren (Stipiturus mallee) is a threatened, narrow-range passerine endemic to south-eastern Australia. To inform future conservation measures for this poorly known species, we used ecological niche factor analysis, habitat suitability modelling and distance sampling to determine landscape-scale habitat requirements and estimate the population size. Using GIS software, we integrated digital layers of ecogeographic variables with; (1) presence-only observations to derive and validate a habitat suitability model using ecological niche factor analysis, and (2) distance sampling to determine population distribution and densities across vegetation types. We detected populations in only five of seven reserves which they had occupied in 2000. We estimate the global population size to be 16,821 individuals (range 8431-39, 104), 68% greater than the previously estimated 10,000 individuals, with a single large reserve containing the majority (∼92%) of the global population. The Mallee Emu-wren is a habitat specialist, primarily occurring in mallee-Triodia vegetation that has not been burnt for at least 15 years. The highest densities were in vegetation associations containing at least a 15% cover of Triodia, however, time since the habitat was last burnt was the overriding factor in determining densities. Large-scale wildfires are a pervasive threat to the global status of the Mallee Emu-wren, and the risk to remaining populations is exacerbated by the adverse impact of prolonged drought and the potential for altered fire regimes caused by global warming. Evaluation of the global population status, and the continued wildfire threat warranted recent reclassification of the Mallee Emu-wren from Vulnerable to Endangered according to IUCN Red List categories and criteria. 相似文献
14.
Alan Woolf Clayton K. NielsenTheodore Weber Tara J. Gibbs-Kieninger 《Biological conservation》2002,104(2):191-198
We used sighting location and remotely sensed habitat data, multivariate statistical techniques, and a geographic information system to model bobcat (Lynx rufus) habitat in Illinois, thereby providing state wildlife managers with information to review the listing of bobcats as a state-threatened species and contribute to the development of a statewide management plan. We used canonical discriminant function analysis to model presence/absence and relative abundance of bobcats statewide. These models suggested that bobcats occurred in moderate to high abundance in 23 of 98 counties statewide (23%). We used stepwise logistic regression (SLR) analysis to model statewide habitat suitability. Spatial modeling of the SLR equation predicted that 29% of Illinois contained suitable habitat classified as P>0.50. Models were accurate when validated with an independent data set and indicated the importance of woods-related habitat variables to bobcats. In conclusion, these models provided tools to rapidly assess status that contributed to delisting bobcats as a threatened species in Illinois and provided further information to guide conservation efforts. 相似文献
15.
Barbara J. Anderson Beatrice E. Arroyo Yvonne C. Collingham Simon Gillings Innes M.W. Sim Steve M. Redpath 《Biological conservation》2009,142(3):488-258
Distribution models are commonly used to generalise across species distributions, to project future potential range changes, and to identify potential areas for species reintroductions and recovery plans. Building several models that incorporate different potential causal factors is a useful way of formalising alternative hypotheses. We developed a series of models to test hypotheses about the factors influencing the distribution of a species of conservation importance - the hen harrier Circus cyaneus.A climate-based model using continental distribution data was consistent with the continental distribution and observational studies in Britain. According to the climate-model the parts of Britain occupied by the hen harrier are the least climatically suitable.Habitat-based models using detailed distribution data from seven Scottish areas explained the recent British distribution well, with birds largely confined to heather dominated areas. These patterns were inconsistent with historical data on the species’ distribution, its habitat use in other parts of its range and with the climate-based model.Our burn intensity index of gamekeeper activity was highly correlated with climatic suitability within the best 25% of 10 km squares by modelled habitat suitability, negatively associated with the productivity data and associated with a decrease in abundances between 1998 and 2004. Gamekeeper activity may be keeping hen harriers out of the most climatically suitable areas with habitat similar to that which they currently occupy within Britain and or keeping the population numbers too low and isolated for the natural re-expansion of the species into parts of the range where it was historically extirpated. 相似文献
16.
Indices are needed in habitat conservation and restoration to provide repeatable measures relevant to conservation goals. A monitoring and research program was established at Nachusa Grasslands in north-central Illinois (USA) to assess progress in tallgrass prairie restoration and reconstruction efforts and evaluate the effectiveness of indices used to measure community-level properties related to vegetation integrity. Indices selected for comparison included standard diversity measures (e.g., Shannon-Weiner Index, Evenness, Species Richness) and indices developed specifically to estimate vegetation integrity. These latter indices included two unweighted diversity indices, the Species Richness Index and Native Richness Index, and two indices weighted by characteristics of species composition, the Floristic Quality Index (FQI) and its component Mean Coefficient of Conservatism (Mean C). A coefficient of conservatism (CC) is an integer ranging from 0 to 10 assigned a priori to each taxon in a regional flora that estimates the fidelity of a species to natural areas (non-native and most ruderal species are assigned 0 or low values, respectively; species known primarily from natural areas are assigned higher values). All indices compared in this study were calculated using vegetation data collected from equal-sized sampling grids stratified across seven prairie units. The units included remnants and plantings representing a wide range of habitat quality. The FQI and Mean C explained the most variation among sites and were most effective at distinguishing recognized qualitative differences indicating they can be more informative than traditional species-diversity measures in assessing floristic integrity within community types. The FQI and Mean C are applicable to both quantitative ecological monitoring and plotless survey methods. 相似文献
17.
In contrast to the body of work in more mesic habitats, few studies have examined boundary processes between natural and anthropogenic desert landscapes. Our research examined processes occurring at boundaries between a desert sand dune community and an encroaching suburban habitat. We measured responses to an anthropogenic boundary by species from multiple trophic levels, and incorporated measures of habitat suitability, and temporal variation, at multiple spatial scales. At an edge versus core habitat scale the only aeolian sand species that demonstrated an unambiguous negative response to the anthropogenic habitat edges was the flat-tailed horned lizard (Phrynosoma mcallii). Conversely loggerhead shrikes (Lanius ludovicianus) demonstrated a positive response to that edge. At a finer scale, species that exhibited a response to a habitat edge within the first 250 m included the horned lizards along with desert kangaroo rats (Dipodomys deserti). The latter species’ response was confined to 25 m from the edge. For the flat-tailed horned lizard, edge effects were measured up to 150 m from the habitat boundary. Three potential causal hypotheses were explored to explain the edge effect on horned lizards: (1) invasions of exotic ant species reducing potential prey for the lizards; (2) road avoidance and road associated mortalities; and (3) predation from a suite of avian predators whose occurrence and abundance may be augmented by resources available in the suburban habitat. We rejected the exotic ant hypothesis due to the absence of exotic ants within the boundary region, and because native ant species (prey for horned lizards) did not show an edge effect. Our data supported the predation and road mortality hypotheses. Mechanisms for regulating population dynamics of desert species are often “bottom-up,” stochastic processes driven by precipitation. The juxtaposition of an anthropogenic edge appears to have created a shift to a “top-down,” predator-mediated dynamic for these lizards. 相似文献
18.
Boris Schröder 《植物养料与土壤学杂志》2008,171(3):325-337
19.
Understory vegetation is an important habitat component for many wildlife species. Previous broad-scale studies on biodiversity and wildlife habitat have suffered from a lack of detailed information about understory distribution. Consequently, it is unclear how understory distribution influences the analysis of habitat quantity and spatial distribution. To address this problem, we compared estimates of giant panda (Ailuropoda melanoleuca) habitat with and without understory bamboo. The results show that the spatial distribution of bamboo has a substantial effect on the quantity and spatial arrangement of panda habitat. Total amount of estimated habitat decreased by 29-52% and decreased connectivity was notable after bamboo information was incorporated into the analyses. The decreases in the quantity and quality of panda habitat resulted in a decrease of 41% in the estimated carrying capacity. Our results suggest that it is necessary to incorporate understory vegetation into large-scale wildlife habitat research and management to avoid overestimation of habitat and improve broad-scale analyses of species distributions and biodiversity estimates in general. 相似文献
20.
Nina Klar Néstor Fernández Stephanie Kramer-Schadt Mathias Herrmann 《Biological conservation》2008,141(1):308-319
Populations of the European wildcat (Felis silvestris) are only slowly recovering in Central Europe after a severe decline in the last centuries and require specific conservation plans in many areas. However, detailed information on wildcat occurrence and habitat requirements is still scarce and controversial. We present a fine-scale habitat selection model for wildcats based on detailed species and land use information and evaluate its accuracy to predict habitat distribution in new areas. We analysed habitat use within home ranges using single locations of 12 radio-tracked individuals from south western Germany. Several competing models were fitted and compared using generalised linear mixed models (GLMM) and information-theoretic approaches. Radio-tracking data of 9 and 10 wildcats from two distant areas were used to evaluate the models. The selected model predicted habitat associated to close distance to forest, watercourses and meadows and a critical distance to villages, single houses and roads. To predict area suitable for home ranges we superimposed rules derived from home range attributes at a higher level of selection. Predictions from the combination of the fine-scale habitat model and home range rules matched well with more than 2000 wildcat observations of south-western Germany. We discuss the application of the model in wildcat conservation for finding potential reintroduction sites, identifying small isolated populations and aiding in the evaluation of the needs of mitigation and compensation within the scope of the European Habitats Directive. 相似文献