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基于InVEST模型评估土地整治对生境质量的影响   总被引:7,自引:3,他引:4       下载免费PDF全文
土地整治通过对土地资源及其利用方式再组织和再优化影响生境斑块之间物质流、能量流的循环过程,从而改变区域生境质量和分布格局.该文以大安市土地整治重大项目为例,采用InVEST模型分析了土地整治对生境质量的影响.研究表明:1)土地整治前(2008年)、整治中(2011年)、整治后(2014年),耕地、草地和盐碱地均为项目区的主要土地利用类型;2)土地整治后,大量的盐碱地和草地转变为耕地,耕地面积由整治前的14.43%上升到71.19%;3)土地整治中,项目区的生境质量得分由整治前的0.194下降到0.189,整治后又上升到0.214;4)土地整治工程改善了项目区的生境质量,但整治完成后生境质量改善效果经历了先下降后上升的过程,在整治完成3~4 a时,生境质量仅比整治前提高了0.06左右,整治完成4 a之后,生境质量开始逐渐好转.研究结果可为土地整治工作中的生境及生物多样性保护工作提供科学依据.  相似文献
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Most current wildlife habitat models, such as resource selection functions, typically assume a static environment, extrapolate poorly in space and time, and often lack linkages to population processes. We submit that more mechanistic habitat models that directly consider bottom-up resources affecting growth and reproduction (i.e., food) and top-down limitations affecting survival are needed to effectively predict habitat quality, especially in the presence of rapid environmental change. Here we present a general model for estimating potential habitat quality (relating to growth and reproduction) and realised habitat quality (accounting for survival) using basic knowledge of the species’ seasonal diet, predicted locations of food resource patches and regional patterns in mortality risk. We illustrate our model for a threatened population of grizzly bears in west-central Alberta. Bi-monthly potential habitat quality successfully predicted habitat selection by radio-collared grizzly bears, while multi-seasonal realised habitat quality predicted patterns in occupancy-abundance as measured from unique bears at hair-snag sites. Bottom-up resources therefore predicted patterns of habitat selection, while top-down processes (survival) were necessary to scale-up to population measures. We suggest that more direct measures of resources and environments that affect growth, reproduction and survival, as well as match the temporal scale of animal behaviour, be considered when developing wildlife habitat models.  相似文献
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The effects of forest continuity at local scale for red-listed and indicator species of epiphytic lichens and bryophytes were investigated in 150 Fagus sylvatica stands in southern Sweden. Stands having forest continuity (n = 106) had continuous forest cover more than 350 years, whereas stands lacking continuity (n = 44) had forest cover less than 160 years. Forest continuity was identified by comparing a sequence of historical maps with a modern survey of beech forests. In the field woody beech substrates were searched for the epiphytes of interest. A number of environmental and spatial variables were inventoried and compiled for each stand. In all 64 species (51 lichens, 13 bryophytes) were found in the stands having continuity, and 21 (14 lichens, 7 bryophytes) in the stands lacking continuity. Controlling for the different number of surveyed stands, stands having continuity had significantly more species of lichens, but not of bryophytes. In the stands lacking continuity we did not find lichens associated with the very late succession stage. The quantity of substrates, stand age and forest continuity were the three most important factors explaining species richness as well as composition of studied epiphytes. The effect of continuity was probably due to a combination of a higher substrate quality, mainly old beeches, and a longer time available for colonization. Also, we found strong positive correlations between number of indicator and red-listed epiphyte species. In short-term conservation old stands having continuity, containing suitable substrates and indicator species are target areas.  相似文献
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Offset schemes are advocated as a way that continued development and environmental restoration can be achieved concurrently. We used a simple modelling approach to evaluate proposed offsets schemes, with scenarios that required offsetting the impacts of clearing woodlands either by revegetation of cleared land or by improving the habitat value of degraded woodland. Each simulation used the attribute table of a single GIS polygon layer to obtain data and record results. We investigated the likely consequences of these schemes for three groups of species with different foraging resource requirements: shrub-dependent; canopy-dependent and old tree-dependent. Only the shrub-dependent group, whose requirements could be rapidly grown, saw increases in suitable habitat in the landscape within our 30 year simulations. The habitat of the canopy-dependent group initially declined but began to increase towards the end of some simulations, while the old tree-dependent group’s habitat declined. When a simple measure of spatial configuration was considered further differences between the schemes were highlighted. The simulation results demonstrate that assessing only the eventual benefit score of a scheme can hide the losses sustained by some elements of biodiversity. We recommend this type of simple modelling approach as the first step in determining whether a proposed offsets scheme is worth investigating further. In particular, the ability to represent the scheme’s predicted consequences as maps and graphs assists decision makers in judging whether the scheme has sufficient merit to warrant a full assessment and subsequent implementation; or needs some adjustments to achieve its aims, or is seriously flawed.  相似文献
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Reintroductions are an important tool in conservation biology but frequently fail. Factors influencing reintroduction ‘success’ are rarely tested experimentally. We examined the relationship between habitat quality and reintroduction success in an experimental reintroduction of populations of water voles (Arvicola terrestris) in the UK.We released cohorts of 44 water voles into 12 replicate 800 m stretches of river, each supporting a different habitat abundance. Water voles initially established at nine sites, failing to establish at three sites due to predation from American mink (two sites) and atypically severe flooding post-release (one site). For sites where voles established, at those with higher vegetation abundance more of the release cohort survived (initial survival rates range 0.43-0.61), and post-establishment survival rates (range 0.45-0.80) and population densities (range 2.1-5.4 voles per 100 m of habitat) were higher. A further two populations were lost to American mink predation post-establishment. Reintroductions are commonly designated as either a ‘success’ or a ‘failure’. The principal cause of a failed release in our study was insufficient mink control. However, whilst seven of our 12 reintroductions were ‘successful’, our results indicated substantial variation in the population densities and survival rates that the replicate habitats could support. This highlights the need to ensure that any habitat selected for a reintroduction is the best obtainable.  相似文献
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The occupancy probability of 35 large-bodied bird and mammal species was examined in relation to patch- and landscape-scale habitat and disturbance variables in 147 forest patches distributed throughout the Mexican Yucatán Peninsula. Occupancy was assessed on the basis of interviews with local informants. The most important predictors of vertebrate species richness, composition, and patch occupancy were human population density and the extent and quality of forest cover. Most forest species responded positively to forest extent, while felids in particular were sensitive to human population density. However, the effects of human density on patch occupancy operated at extremely local scales. Effects were stronger at a smaller grain size, offering optimistic prospects for conservation strategies that incorporate human population effects. Three arboreal frugivores (Ateles geoffroyi, Alouatta pigra, and Ramphastos sulfuratus) were strongly associated with total basal area of trees bearing fleshy fruits. The degree of hunting pressure was not related to human population density, and affected the occupancy probability of three game species, two of which (Mazama spp., Crax rubra) are among the most preferred prey across the Yucatán Peninsula. Levels of patch occupancy across this region varied considerably among species, and were best explained by body size and degree of forest habitat specificity, large-bodied species and habitat specialists being the most vulnerable. This study provides a quantitative assessment of the conservation potential of large vertebrates in Mesoamerica and identifies disturbance-sensitive species. This can inform regional-scale conservation planning at a time when low deforestation in parts of the Yucatán Peninsula still provides a narrow window of conservation opportunity given the rapid human population growth.  相似文献
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Metapopulation theory is one of the most popular approaches to identify the factors affecting the spatial and temporal dynamics of populations in fragmented habitat networks. Habitat quality, patch area and isolation are mainly focused on when analyzing distribution patterns in fragmented landscapes. The effects of landscape heterogeneity in the non-occupied matrix, however, have been largely neglected. Here, we determined the relative importance of patch quality and landscape attributes on the occurrence, density and extinction of the Dupont’s lark (Chersophilus duponti), an endangered steppe passerine whose habitat has been extremely reduced to highly isolated and fragmented patches embedded in a mainly unsuitable landscape matrix. Habitat patch quality, measured in terms of vegetation structure, grazing pressure, arthropod availability, predator abundance, and inter-specific competition, did not affect occurrence, density or extinction. At the landscape scale, however, the species’ occurrence was principally determined by the interactions among patch size, geographic isolation and landscape matrix. Isolation had the main independent contribution to explaining the probability of occurrence, followed by landscape matrix composition and patch size. The species’ density was negatively correlated to patch size, suggesting crowding effects in small fragments, while extinction events were exclusively related to isolation. Our findings suggest that landscape rather than local population characteristics are crucial in determining the patterns of distribution and abundance of non-equilibrium populations in highly fragmented habitat networks. Consequently, conservation measures for these species should simultaneously involve patch size, isolation and landscape matrix and apply to the entire metapopulation rather than to particular patches.  相似文献
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A principal challenge of species conservation is to identify the specific habitats that are essential for long-term persistence or recovery of imperiled species. However, many commonly used approaches to identify important habitats do not provide direct insight into the contribution of those habitats to population persistence. To assess how habitats contribute to overall population viability and characterize their relative importance, a spatially-explicit population viability model was used to integrate a species occurrence model with habitat quality and demographic information to simulate the population dynamics of the Ord’s kangaroo rat (Dipodomys ordii) in Alberta, Canada. Long-term productivity (births-deaths) in each patch was simulated and iterative patch removal experiments were conducted to generate estimates of the relative contribution of habitat types to overall population viability. Our results indicated that natural dune habitats are crucial for population viability, while disturbed/human-created habitats make a minor contribution to population persistence. The results also suggest that the habitats currently available to Ord’s kangaroo rats in Alberta are unlikely to support long-term persistence. Our approach was useful for identifying habitats that did not contribute to population viability. A large proportion of habitat (39%) represented sinks and their removal increased estimated population viability. The integration of population dynamics with habitat quality and occurrence data can be invaluable when assessing critical habitat, particularly in regions with variable habitat quality. Approaches that do not incorporate population dynamics may undermine conservation efforts by under- or over-estimating the value of habitats, erroneously protecting sink habitats, or failing to prioritize key source habitats.  相似文献
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