نتایج جستجو برای: ecological patches

تعداد نتایج: 122902  

2006
Alessandro Colombo

Goal To investigate how evolution affects synchronization in ecological networks. Plant and animal populations seldom live in a single homogeneous area, since landscapes are often spatially fragmented into various patches. Migration between different patches may be considerable, especially when patches are not too distant from one another. Such spatially structured populations are described as ...

Journal: :محیط شناسی 0
مهسا یزدانپناه کارشناسی ارشد مدیریت و برنامه ریزی محیط زیست، دانشکدۀ محیط زیست، دانشگاه تهران احمدرضا یاوری دانشیار گروه برنامه ریزی و مدیریت محیط زیست، دانشکدۀ محیط زیست، دانشگاه تهران لعبت زبردست استادیار گروه برنامه ریزی و مدیریت محیط زیست، دانشکدۀ محیط زیست، دانشگاه تهران سیده آل محمد کارشناسی ارشد برنامه ریزی و مدیریت محیط زیست

introduction “green infrastructure” is a term that describes the abundance and distribution of natural features providing ecological services necessary for community wellbeing specially in urban areas where these are limited. green infrastructure is increasingly espoused by landscape conservation and metropolitan planning because it is an effective way to surrogate ecological network functions ...

2017
ROBERT M. MAY

1. We take a previously studied model for two species one of which is competitively inferior coexisting in a patchy environment, and examine the effects of removing patches (that is, of decreasing the amount of available habitat). 2. Habitat destruction or patch removal reduces the number (and proportion) of patches occupied by the superior competitor, but can result in an increase in the total...

2013
Hamid Siroosi Gholam Ali Heshmati Abdolrassoul Salman Mahini Hamid Reza Naseri

Preservation of ecosystems requires an understanding of the ecosystem processes that regulate ecosystem resources. Patches and inter-patch features are parts of the ecosystem that are partially responsible for effects on transporting and storing materials in the ecosystem. The structural features of ecological patches including size, number and the average inter-patch length are important becau...

Habitat and ecosystem fragmentation and, consequently, the loss of landscape connectivity are major causes of biodiversity destruction, leading to disruption of material, energy, and information flow at the landscape scale. Given the importance of this issue, the current study aimed to evaluate the ecological connectivity and spatial planning of Qazvin Province, in order to re-establish and pro...

2000
J. S. PARSLOW

parative rapid ammonium uptake by four species of marine phytoplankton. Limnol. Oceanogr. 27: 814-827. -, J. J. MCCARTHY, AND D. G. PEAVEY. 1979. Growth rate influence on the chemical composition of phytoplankton in oceanic waters. Nature 279: 210-215. HEALEY, F. P. 1980. Slope of the Monod equation as an indicator of advantage in nutrient competition. Microb. Ecol. 5: 281-286. HUTCHINSON, G. E...

Journal: :Chaos 2007
Ehud Meron Hezi Yizhaq Erez Gilad

Vegetation patches in drylands are localized structures of biomass and water. We study these structures using a mathematical modeling approach that captures biomass-water feedbacks. Biomass-water structures are found to differ in their spatial forms and ecological functions, depending on species type, soil conditions, precipitation range, and other environmental factors. Asymptotic spot structu...

Journal: :Annals of GIS 2006
Robert Roth A-Xing Zhu Eric Holbus Jesse Papez Jeremy Quan

Reducing fragmentation and increasing interior area of habitat patches are major goals of restoration programs. Most strategies to correct these issues are qualitative based on visual interpretation, rather than quantitative based on the spatial characteristics of patches. To circumvent this, we developed an approach that integrates domain knowledge into an objective and geometric analysis of t...

Journal: :international journal of environmental research 0
s. rasouli graduate faculty of environment, university of tehran, p.o. box 14155-6135, tehran, iran m. makhdoum farkhondeh faculty of natural resources, university of tehran, p.o. box 4111, karaj , iran h.r. jafari graduate faculty of environment, university of tehran, p.o. box 14155-6135, tehran, iran r. suffling faculty of environment, university of waterloo, 200 university avenue west, waterloo, on n2l 3g1, canada b. kiabi faculty of biological science, shahid beheshti university, p.o. box 1983963113, tehran, iran a.r. yavari graduate faculty of environment, university of tehran, p.o. box 14155-6135, tehran, iran

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 ecological...

2007
Simone D. LANGHANS Scott D. TIEGS Urs UEHLINGER Klement TOCKNER Simone D. Langhans

Environmental heterogeneity is a key regulator of ecological processes. Riverine floodplains are particularly heterogeneous and dynamic systems and loss of their natural environmental heterogeneity and dynamism as a consequence of human impacts constitutes their most serious threat. On river floodplains, flow and flood pulses create a shifting mosaic of channels, ponds, bars, islands, and ripar...

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