نتایج جستجو برای: bush encroachment

تعداد نتایج: 6041  

Journal: :مرتع و آبخیزداری 0
بهزاد رایگانی استادیار دانشکده علوم محیط زیست و منابع طبیعی، دانشگاه محیط زیست غلامرضا زهتابیان استاد دانشکده منابع طبیعی، دانشگاه تهران حسین آذرنیوند دانشیار دانشکده منابع طبیعی، دانشگاه تهران سید جمال الدین خواجه الدین استاد دانشکده منابع طبیعی، دانشگاه صنعتی اصفهان سید کاظم علوی پناه استاد دانشکده جغرافیا، دانشگاه تهران

arid and semi-arid areas, due to the sensitive, have variable ecosystems, so continuous assessment and monitoring of the environment is required for most of managerial and adjustment practices. vegetation is one of the most important assessment tools and used as a criterion for evaluation and monitoring of ecosystem functions. in this study, for the first time in the country, we have evaluated ...

2016
Teshome Abate Ayana Angassa

INTRODUCTION Analyzing trends of land use systems and the changes occurred overtime is an effective way of assessing the impacts of land use/land cover (LULC) changes on ecosystem function. It provides important insights for understanding the spatial patterns of land use processes. The rangelands of southern Ethiopia are adversely affected by increased human population pressure, encroachment of...

Journal: :Ecology 2012
Zakary Ratajczak Jesse B Nippert Scott L Collins

Woody encroachment is a widespread and acute phenomenon affecting grasslands and savannas worldwide. We performed a meta-analysis of 29 studies from 13 different grassland/savanna communities in North America to determine the consequences of woody encroachment on plant species richness. In all 13 communities, species richness declined with woody plant encroachment (average decline = 45%). Speci...

2015
Daniel A. Sarr Robert W. Van Kirk Erik S. Jules

For over a century, increases in the abundance of woody plants in savannas have been occurring worldwide in a process known as encroachment. Encroachment into savannas is a significant management concern because it affects the unique values associated with savanna systems, including high levels of both taxonomic and landscape diversity. Improving methods for reconstructing encroachment patterns...

2008
Nicolas Roy

We make explicit the geometric content of Mel’nikov’s method for detecting heteroclinic points between transversally hyperbolic periodic orbits. After developing the general theory of intersections for pairs of family of Lagrangian submanifolds constrained to live in an auxiliary family of submanifolds, we explain how the heteroclinic orbits are detected by the zeros of the Mel’nikov 1-form. Th...

Journal: :مهندسی سازه 0
مهدی ماجدی اصل مهدی یاسی

general kind of encroachment of river is constructing a bridge on it. purpose of encroachment of river is occupation part of river and flood plain for constructing bridge. often being economical of bridge innovation affirmated that most of encroachment take place to river and flood plain, which this encroachment can be in form of embankment in flood plain of river or into the main bed of river ...

Journal: :Ecology letters 2009
Fernando T Maestre Matthew A Bowker María D Puche M Belén Hinojosa Isabel Martínez Pablo García-Palacios Andrea P Castillo Santiago Soliveres Arántzazu L Luzuriaga Ana M Sánchez José A Carreira Antonio Gallardo Adrián Escudero

The worldwide phenomenon of shrub encroachment in grass-dominated dryland ecosystems is commonly associated with desertification. Studies of the purported desertification effects associated with shrub encroachment are often restricted to relatively few study areas, and document a narrow range of possible impacts upon biota and ecosystem processes. We conducted a study in degraded Mediterranean ...

Journal: :Computers & Industrial Engineering 2016
Tingting Li Jinxing Xie Xiaobo Zhao Jiafu Tang

With the development of e-commerce, many wholesale suppliers establish direct channels competing with their retailers. Such competition is often referred to as supplier encroachment. Previous studies assume the perfect rationality of retailers. However, supplier encroachment may trigger the fairness concerns of the retailers as a supplier is also a competitor of its retailer if the supplier enc...

Journal: :Applied vegetation science 2016
Fernando T Maestre David J Eldridge Santiago Soliveres

Shrub encroachment, a global phenomenon with management implications, is examined in two papers in the current issue of Applied Vegetation Science. Barbosa da Silva et al. show that encroachment simplifies herbaceous community, and Pittarello et al. illustrate how pastoral practices can restore encroached grasslands. While detrimental effects of shrub encroachment on grassland vegetation are of...

2013
Heather L. Throop Kate Lajtha Marc Kramer

Woody encroachment has dramatically changed land cover patterns in arid and semiarid systems (drylands) worldwide over the past 150 years. This change is known to influence bulk soil carbon (C) pools, but the implications for dynamics and stability of these pools are not well understood. Working in a Chihuahuan Desert C4 grassland encroached by C3 creosote bush (Larrea tridentata), we used two ...

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