نتایج جستجو برای: and habitat uses
تعداد نتایج: 16840317 فیلتر نتایج به سال:
We consider a population living in a patchy environment that varies stochastically in space and time. The population is composed of two morphs (that is, individuals of the same species with different genotypes). In terms of survival and reproductive success, the associated phenotypes differ only in their habitat selection strategies. We compute invasion rates corresponding to the rates at which...
Determining the factors that influence migratory population abundance has been constrained by the inability to connect events in different periods of the annual cycle. Carry-over effects are events that occur in one season but influence individual success the following season and recent empirical evidence suggests that they may play an important role in migratory population dynamics. Using a lo...
Population trends represent a minimum amount of information required to assess the conservation status of a species. However, understanding and detecting trends can be complicated by variation among habitats and regions, and by dispersal connecting habitats through source-sink dynamics. We analyzed trends in breeding populations between habitats and regions to better understand the overall dyna...
Classical metapopulations are groups of local populations living in networks of spatially distinct habitat patches in a balance between local extinctions and recolonizations of empty habitat. Models are needed for understanding and predicting metapopulation dynamics in changing landscapes. One particularly important question is what is the effect of habitat loss to the persistence of a metapopu...
the relationship between some habitat factors and fish assemblage was analyzed in the taleghan river, alborz province, iran. fish specimens from thirty-three sites were sampled by electrofishing device in october 2014. the habitat parameters, including elevation (m), water depth (cm), river width (m), river slope (%), current velocity (m.s-1), number of large stone (> 15 cm), average stone diam...
the objective of this study was to diagnose integrative ecological health of an urban stream,which is located in the asian temperate region. the research approach was primarily based on the index ofbiological integrity (ibi) using fish assemblage and a qualitative habitat evaluation index (qhei). and these indexes were compared with long-term conventional chemical dataset during 1996-2005. for ...
Rinne, J.N., 1990. The utility of stream habitat and biota for identifying potential conflicting forest land uses: Montane riparian areas. For. Ecol. Manage., 33/34: 363-383. Investigations since 1960 on the effects of land-management practices on riparian-stream systems often have produced contradictory results. Inconsistencies have occurred, in part, because of efforts that have not been tota...
In many habitat evaluation methods, the abundance data are used. Such data are not available for many species. However, there is some website that provides the presence data of species that are based on the studies made. The present study used the PATREC method to estimate the habitat suitability of the Caspian Sea for the genus Alosa. The PATREC method needs abundance data to calculate the pri...
Faunal responses to anthropogenic habitat modification represent an important aspect of global change. In Puerto Rico, two species of arboreal lizard, Anolis cristatellus and A. stratulus, are commonly encountered in urban areas, yet seem to use the urban habitat in different ways. In this study, we quantified differences in habitat use between these two species in an urban setting. For each sp...
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