نتایج جستجو برای: ecological patches

تعداد نتایج: 122902  

Journal: :international journal of advanced design and manufacturing technology 0
sa'id golabi javad jafari fesharaki

using piezoelectric patches the stress concentration around a hole on a plate under tension is reduced and controlled. to attain the reduction in stress two placements for piezoelectric patches is investigated. the first location is top/bottom of the hole with compression induced strain and the second is left/right of the hole with tension induced strains to control the stress flow. the result ...

Journal: :تحقیقات آب و خاک ایران 0
آرش کرمی کارشناسی ارشد، دانشگاه تهران قوام الدین زاهدی دانشیار، دانشگاه تهران جهانگیر فقهی دانشیار، دانشگاه تهران

some soil physical and chemical characteristics were analyzed in order to reveal the relationship between forest soils and regeneration patches. gorazbon district of kheyrud was selected as a case study for the research area. all regeneration patches were recorded using gps device. to assess the spatial structure and to quantify the metrics of regeneration patches, analyzing of landscape metric...

Journal: :محیط زیست طبیعی 0
آرش کرمی کارشناس ارشد رشتۀ جنگلداری و اقتصادجنگل دانشکدۀ منابع طبیعی، دانشگاه تهرا جهانگیر فقهی دانشیار گروه جنگلداری و اقتصاد جنگل دانشکدۀ منابع طبیعی، دانشگاه تهران محمدرضا مروی مهاجر استادگروه جنگلداری و اقتصاد جنگل دانشکدۀ منابع طبیعی، دانشگاه تهران

without doubt is one important aspects of sustainable forest management the continuing forest regeneration. identify and determine is effective dispersal and distribution pattern of regeneration patches in various types of forest and its evolution, in maintaining biodiversity in natural ecosystems. purpose was chosen of gorazbon district kheyrod forest for study, all patches regeneration were l...

1998
Michael Doebeli Graeme D. Ruxton

Many studies of metapopulation models assume that spatially extended populations occupy a network of identical habitat patches, each coupled to its nearest neighbouring patches by density-independent dispersal. Much previous work has focused on the temporal stability of spatially homogeneous equilibrium states of the metapopulation, and one of the main predictions of such models is that the sta...

Journal: :محیط شناسی 0
فرود آذری دهکردی استادیار گروه برنامه ریزی و مدیریت دانشکدة محیط زیست، دانشگاه تهران نوشین خزاعی دانشجوی کارشناسی ارشد، دانشکدة محیط زیست دانشگاه تهران

degradation model was introduced as an instrument of environmental impact assessment (eia) in iran. several methods are introduced in rapid environmental assessment, but none of them have evaluated landscape level. thus, the main objective of this research is to introduce a new spatial method for eia by using landscape metrics. a benefit of rapid assessment by using ecological landscape metrics...

2003
JOHN L. ORROCK BRENT J. DANIELSON MOLLY J. BURNS DOUGLAS J. LEVEY

Corridors that connect patches of disjunct habitat may be promising tools for mediating the negative impacts of habitat fragmentation, but little is known about how corridors affect ecological interactions. In eight 12-ha experimental landscapes, we examined how corridors affect the impact of invertebrate, rodent, and avian seed predators on pokeweed, Phytolacca americana. Over 13 months in 200...

2013
James C. Beasley Zachary H. Olson William S. Beatty Guha Dharmarajan Olin E. Rhodes

Anthropogenic changes in land use and the extirpation of apex predators have facilitated explosive growth of mesopredator populations. Consequently, many species have been subjected to extensive control throughout portions of their range due to their integral role as generalist predators and reservoirs of zoonotic disease. Yet, few studies have monitored the effects of landscape composition or ...

2016
Hao Xu Jing Cui

In order to explore the change of Green Space in Suzhou, a central City in China's Yangtze River Delta, and reveal the spatial characteristics, ecological benefits and its impact mechanism, this study extracted a distribution map of the patches of green spaces in Suzhou using Landsat remote-sensing image data from 1998 and 2007, analyzed and assessed the changes in scale and spatial layout of t...

2004
Rebecca S.H. Kennedy Thomas A. Spies

Changes to minor patch types in forested landscapes may have large consequences for forest biodiversity. The effects of forest management and environment on these secondary patch types are often poorly understood. For example, do early-to-mid successional minor patch types become more expansive as late successional forest types are fragmented or do they also become more fragmented in managed la...

2004
J. R. MCLAREN R. L. JEFFERIES

1 Vegetation mosaics of grassland and exposed soil are often the outcome of intense herbivory and represent alternate stable states, although the vegetational and soil processes that both initiate and maintain the states in response to herbivory are poorly understood. 2 The vegetation mosaic resulting from grubbing by geese was examined on the intertidal flats at La Pérouse Bay, Manitoba. Soil ...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید