The term critical habitat is used to describe the subset of habitat that is essential to the survival and recovery of species. Some countries legally require that critical habitat of listed threatened and endangered species be identified and protected. However, there is little evidence to suggest that the identification of critical habitat has had much impact on species recovery. We hypothesize...

I challenge (1) the assumption that habitat patches are natural units of measurement for species richness, and (2) the assumption of distinct effects of habitat patch size and isolation on species richness. I propose a simpler view of the relationship between habitat distribution and species richness, the ‘habitat amount hypothesis’, and I suggest ways of testing it. The habitat amount hypothes...

Habitats are composed of multiple variables, each of which may affect one or more population demographic rates. The patterns of correlation among habitat variables can introduce correlations among demographic rates, even if any single habitat variable affects only a single demographic rate and is independent of others. I present a simple model in which habitat is composed of two continuous habi...

—The use of model-predicted, local-scale habitat data as inputs in analyses intended to evaluate multiscale fish assemblage–habitat relationships in streams has become increasingly common as the scale at which such studies are conducted has increased. We used fish assemblage and habitat data from 208 wadeable streams in Wisconsin and Michigan to determine whether model-predicted habitat data wo...

■ Abstract The literature on effects of habitat fragmentation on biodiversity is huge. It is also very diverse, with different authors measuring fragmentation in different ways and, as a consequence, drawing different conclusions regarding both the magnitude and direction of its effects. Habitat fragmentation is usually defined as a landscape-scale process involving both habitat loss and the br...

the aim of this study was to investigate the effect of reforestation on physical and chemical soil properties particularly soil carbon storage in the berenjastanak forest. forestations were including acer velotinum boiss., fraxinus excelsior l., populus nigra l. and pinus brutia ten. a witness forest with mixed species was selected as region potential. four soil profiles were drilled in each fo...

isfahan wild sheep ovis orientalis isphahanica is listed as vulnerable in the iucn red list of threatened species. adequate knowledge on habitat requirements and environmental factors determining the niche of a species is central to its conservation programmes. however, there is scarcity of data on habitat associations of this species in iran. a gis-based model, using presence-only data, was us...

identification of rapid degradation of ecological resources requires effective environmental monitoring including ecological integrity assessment .our first aim is to analyze ecological integrity in a landscape context while developing a method to assess integrity in spite of a dearth of historical data. we used a spatial-temporal reference framework for land cover maps for assessing ecologica...

We investigate the scenario in which some amount of higher quality habitat is destroyed and is then replaced by some undetermined amount of lower quality habitat. We examined how much low-quality habitat would need to be created to maintain the equilibrium population abundance in the entire geographic area. Using a source–sink model, we find that (1) the number of hectares of created habitat pe...