نتایج جستجو برای: structural habitat variables

تعداد نتایج: 745422  

ترکش, مصطفی, رنجبر, ندا, شاهقلیان, جواد, همامی, محمود رضا,

Knowledge of species’ habitat needs is considered as one of the requirements of wildlife management. We studied seasonal habitat suitability and habitat associations of wild goat (Capra aegagrus) in Kolah-Qazi National Park, one of its typical habitats in central Asia, using Maximum Entropy approach. The study area was confined to mountainous areas as the potential habitat of the wild goat. Ele...

2006
Scott Goetz Daniel Steinberg Ralph Dubayah Bryan Blair

Habitat heterogeneity has long been recognized as a fundamental variable indicative of species diversity, in terms of both richness and abundance. Satellite remote sensing data sets can be useful for quantifying habitat heterogeneity across a range of spatial scales. Past remote sensing analyses of species diversity have largely been limited to correlative studies based on the use of vegetation...

al. et R. Zarkami,

Support vector machine (SVM) was used to analyze the occurrence of roach in Flemish stream basins (Belgium). Several habitat and physico?chemical variables were used as inputs for the model development. The biotic variable merely consisted of abundance data which was used for predicting presence/absence of roach. Genetic algorithm (GA) was combined with SVM in order to select the most important...

Journal: :Environmental management 1999
LAMMERT ALLAN

/ Fish and macroinvertebrate assemblage composition, instream habitat features and surrounding land use were assessed in an agriculturally developed watershed to relate overall biotic condition to patterns of land use and channel structure. Six 100-m reaches were sampled on each of three first-order warm-water tributaries of the River Raisin in southeastern Michigan. Comparisons among sites and...

Journal: :caspian journal of environmental sciences 2012
r. zarkami al. et

support vector machine (svm) was used to analyze the occurrence of roach in flemish stream basins (belgium). several habitat and physico?chemical variables were used as inputs for the model development. the biotic variable merely consisted of abundance data which was used for predicting presence/absence of roach. genetic algorithm (ga) was combined with svm in order to select the most important...

2010
Pamela S.D. MacRae James H. Cowan

Louisiana wetlands are disappearing at a dramatic rate, providing an impetus for identifying the relative value to fishes of a matrix of estuarine habitat types. The distribution, relative abundance, biomass, and length of spotted seatrout, Cynoscion nebulosus (Cuvier) were examined in Barataria Bay, Louisiana, in relation to habitat type and abiotic variables. Spotted seatrout were collected f...

2012
S. Aghainajafi Zadeh M. R. Hemami F. Heydari

Asiatic Houbara ( Chlamydotis macqueenii ) is a flagship and vulnerable species. In-situ conservation of this threatened species demands for knowledge of its habitat selection. The aim of this study was to determine habitat variables influencing birds wintering and breeding selection in semiarid central Iran. Habitat features of the detected nest and pellet sites were compared with paired and r...

Journal: :محیط زیست طبیعی 0
صیاد شیخی ئیلانلو دانشگاه علوم کشاورزی و منابع طبیعی گرگان مظاهر معین الدینی دانشگاه تهران مصطفی قلی پور دانشگاه علوم کشاورزی و منابع طبیعی گرگان علی شیخی دانشگاه حکیم سبزواری هادی کراچی دانشگاه حکیم سبزواری

habitat recognition and knowledge of habitat requirements are extremely important to the wildlife conservation, particularly for endangered and vulnerable species. the purpose of the study was to determine which ecological and habitat factors contribute the distribution of black billed sandgrous (pterocles orientalis) in shirahmad wildlife refuge. sampling was performed in two season (spring an...

2007
Boris Schröder

Figure 1: Principle of habitat modelling: sampling of species distribution data (here: presence-absence data) and selected predictor variables; estimating an empirical, predictive model (in this case: by logistic regression a generalised linear model for binary response variables, other, more flexible approaches are generalised additive models, classification and regression trees, artificial ne...

2004
Craig Syms Geoffrey P. Jones

Coral reef lagoons and back reef areas are composed more of sand than hard reef habitat. They support a diverse mix of fishes, including species restricted to sandy habitats and those dependent on both hard and soft substrata. However the resident assemblages associated with sand and the factors affecting their distribution and abundance are poorly understood. Here we examine spatial co-variati...

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