نتایج جستجو برای: habitat

تعداد نتایج: 54289  

Ali Mahdavi Mojtaba Jamshidifard

To determine the potential habitat of two rangeland species of Salsola rigidaand Agropyron trichophorum in Qasr-e-Shirin, Iran, Geographic Information Systems(GIS) and Remote Sensing (RS) techniques were used. At first, several maps (vegetationcover and land uses maps and thematic maps of various organizations) were collected orprepared. For digitizing geology, vegetation and conventional state...

Journal: :اکو هیدرولوژی 0
مهدی صدیق کیا . دانشجوی دکتری سازه‏های آبی، دانشگاه تربیت مدرس، تهران سید علی ایوب زاده دانشیار گروه سازه‏های آبی، دانشگاه تربیت مدرس، تهران محبوبه حاجی اسماعیلی کارشناس ارشد سازه‏های آبی، دانشگاه تربیت مدرس، تهران

in the present research necessities of instream flow needs (ifn) assessment in the rivers with focusing on delichai river as case study is investigated using the hydro-ecological methods. at first, ifn is assessed using two common approaches of the tennant and wetted perimeter. then considering that rainbow trout is the most important and dominant species in this river, ecological condition of ...

2005
Kevin McGarigal Sam Cushman Claudia Regan

Anthropogenic habitat loss and fragmentation have been implicated as among the key drivers of the burgeoning global biodiversity crisis. In response, there is a growing mandate among natural resource managers to evaluate the impacts of proposed management actions on the extent and fragmentation of habitats. Unfortunately, few guidelines exist to help managers understand the many complex issues ...

2010
Andrés Viña Weihua Xu Yu Li Zhiyun Ouyang Ruth DeFries Jianguo Liu

The range-wide habitat status of many endangered species is unclear. We evaluated the status and spatial distribution of the habitat of the endangered giant panda (Ailuropoda melanoleuca) across its entire geographic range (i.e., six mountain regions located in Sichuan, Shaanxi and Gansu provinces, China) by integrating field and remotely sensed data to develop a habitat distribution model. Res...

2006
François Hamel Lionel Roques

We study a reaction-diffusion model in a binary environment made of habitat and non-habitat regions. Environmental heterogeneity is expressed through the species intrinsic growth rate coefficient. It was known that, for a fixed habitat abundance, species survival depends on habitat arrangements. Our goal is to describe the spatial configurations of habitat that maximise the chances of survival....

Journal: :Mathematical biosciences 2007
Lionel Roques François Hamel

We study a reaction-diffusion model in a binary environment made of habitat and non-habitat regions. Environmental heterogeneity is expressed through the species intrinsic growth rate coefficient. It was known that, for a fixed habitat abundance, species survival depends on habitat arrangements. Our goal is to describe the spatial configurations of habitat that maximise the chances of survival....

1992
M. D. Bryant

Introduction Application of a Hierarchical Habitat Unit Classification System: Stream Habitat and Salmonid Distribution in Ward Creek, Southeast Alaska M.D. Bryant, B.E. Wright, and B.J. Davies A hierarchical classification system separating stream habitat into habitat units defined by stream morphology and hydrology was used in a pre-enhancement stream survey. The system separates habitat unit...

     Climate changes due to changes in a habitat leads to differences in the rate of decomposition and nutrient dynamics of leaflitters, which has many effects on the controlling factors of the decomposition process. In the present study, the rate of decomposition and nutrient dynamics of Norway spruce was evaluated for 363 days in the two forestation sites in the natural and foreign habitats, ...

Journal: :Int. J. Applied Earth Observation and Geoinformation 2015
Paola Mairota Barbara Cafarelli Rocco Labadessa Francesco P. Lovergine Cristina Tarantino Harini Nagendra Raphael K. Didham

Modelling the empirical relationships between habitat quality and species distribution patterns is the first step to understanding human impacts on biodiversity. It is important to build on this understanding to develop a broader conceptual appreciation of the influence of surrounding landscape structure on local habitat quality, across multiple spatial scales. Traditional models which report t...

2015
Bruce A. Manny Edward F. Roseman Gregory Kennedy James C. Boase Jaquelyn M. Craig David H. Bennion Jennifer Read Lynn Vaccaro Justin Chiotti Richard Drouin Rosanne Ellison

Loss of functional habitat in riverine systems is a global fisheries issue. Few studies, however, describe the decision-making approach taken to abate loss of fish spawning habitat. Numerous habitat restoration efforts are underway and documentation of successful restoration techniques for spawning habitat of desirable fish species in large rivers connecting the Laurentian Great Lakes are repor...

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