نتایج جستجو برای: rangeland ecosystems

تعداد نتایج: 48371  

Journal: :مرتع و آبخیزداری 0
غلامعلی حشمتی دانشکده مرتع و آبخیزداری، دانشگاه علوم کشاورزی و منابع طبیعی گرگان، ایران مژگان سادات عظیمی دانشجوی دکتری علوم مرتع، دانشکده مرتع و آبخیزداری، دانشگاه علوم کشاورزی و منابع طبیعی گرگان، ایران پروانه عشوری کارشناس ارشد موسسه تحقیقات جنگل ها و مراتع کشور، ایران

rangeland ecosystem contains various patches with different functions. structural and functional characteristics of rangeland patches are changed by management practices and can be used to interpret management effects. the structural and functional characteristics of fertilized patches in two rangeland ecosystems of ghareh ghir and maraveh tapeh were measured and analyzed in this study. a group...

2010

For most ecosystems, net ecosystem exchange of CO2 (NEE) varies within and among years in response to environmental change. We analyzed measurements of CO2 exchange from eight native rangeland ecosystems in the western United States (58 site-years of data) in order to determine the contributions of photosynthetic and respiratory (physiological) components of CO2 exchange to environmentally caus...

2000
Sven Brückner Kurt Sundermeyer

generalized interactions flexible acquaintances/interactions reactive capabilities pro-active capabilities

2017
Robert A. Masters Roger Sheley ROBERT A. MASTERS ROGER L. SHELEY

Invasive plants reduce the capacity of ecosystems to provide goods and services required by society, alter ecological processes, and can displace desirable species. They can reduce wildlife habitat quality, riparian area integrity, rangeland economic value, and enterprise net returns. The invasion process is regulated by characteristics of the invading plant and the community being invaded. The...

2017
R. Dave Evans Richard A. Gill Valerie T. Eviner

Soil characteristics and functions are critical determinants of rangeland systems and the ecosystem services that they provide. Rangeland soils are extremely diverse, but an emerging understanding is that paradigms developed in more mesic forest ecosystems may not be applicable. Vascular plants, biological soil crusts, and the soil microbial community are the three major functional groups of or...

Land use change as the most important destructive factor in natural ecosystems is a globally problem that changes soil properties. Therefore, correct management and recognition of change aspects on each component of the ecosystem is necessary. This process causes land destruction, ecosystem instability, soil erosion, and more biological threats. Due to increasing land use conversion from rangel...

Journal: :مرتع و آبخیزداری 0
سید علیرضا موسوی عضو هیئت علمی، دانشکده منابع طبیعی، دانشگاه صنعتی اصفهان حسین ارزانی عضو هیئت علمی، دانشکده منابع طبیعی، دانشگاه تهران غلامعلی شرزه ای عضو هیئت علمی، دانشکده اقتصاد، دانشگاه تهران حسین آذرنیوند عضو هیئت علمی، دانشکدة منابع طبیعی، دانشگاه تهران مهدی فرح پور عضو هیئت علمی، مؤسسه تحقیقات جنگل ها و مراتع ایران استفانی انگل رئیس گروه تصمیم ‏سازی و اقتصاد محیط زیست مؤسسه eth سوئیس اسماعیل علیزاده

soil conservation is one of the most important regulative functions of natural ecosystems. this function is of high importance in taleghan watershed due to high erosion quantity and sediment accumulation in taleghan dam reservoir. soil loss reduction, sedimentation control and fertility conservation were considered as different aspects of soil conservation. effect of land use and vegetation cov...

آذرنیوند, حسین, ارزانی , حسین , صادقی‌راد, افشین ,

Evaluation of plant richness and diversity is important in rangeland ecosystems because biological control, conservation of genetic resources and the control of natural ecosystems are possible by identifying diversity. One of the factors affecting the richness and diversity is animals' utilization of the vegetation. Therefore, this research was done to study the plant richness and diversity res...

One of the most important issues in structure-function relationship modeling is that each rangeland has numerous functions and each of them can provide the most benefits in a certain state of that ecosystem. In fact, relationship between structure and function can be varied in different states. After presentation of the Linear Structure-Function Model based on the Clementsian succession theory,...

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