نتایج جستجو برای: forest and pasture coverage

تعداد نتایج: 16859084  

Journal: :New Zealand Journal of Agricultural Research 1960

2016
Seeta A. Sistla Adam B. Roddy Nicholas E. Williams Daniel B. Kramer Kara Stevens Steven D. Allison

Tropical forest conversion to pasture, which drives greenhouse gas emissions, soil degradation, and biodiversity loss, remains a pressing socio-ecological challenge. This problem has spurred increased interest in the potential of small-scale agroforestry systems to couple sustainable agriculture with biodiversity conservation, particularly in rapidly developing areas of the tropics. In addition...

2010
Katie Price C. Rhett Jackson Albert J. Parker

0022-1694/$ see front matter Published by Elsevier doi:10.1016/j.jhydrol.2009.12.041 * Corresponding author. Present address: Ecosys Environmental Protection Agency, 960 College Station United States. Tel.: +1 706 355 8338; fax: +1 706 355 E-mail addresses: [email protected] (K. Price (C.R. Jackson), [email protected] (A.J. Parker). A full understanding of hydrologic response to human impact r...

2007
J. Reilly S. Paltsev B. Felzer X. Wang D. Kicklighter J. Melillo R. Prinn M. Sarofim A. Sokolov C. Wang

Multiple environmental changes will have consequences for global vegetation. To the extent that crop yields and pasture and forest productivity are affected, there can be important economic consequences. We examine the combined effects of changes in climate, increases in carbon dioxide (CO2), and changes in tropospheric ozone on crop, pasture, and forest lands and the consequences for the globa...

Journal: :محیط شناسی 0
محمد جواد امیری دانشجوی دکترای جنگلداری دانشگاه تربیت مدرس نور سید غلامعلی جلالی دانشیار گروه جنگلداری دانشکدة منابع طبیعی دانشگاه تربیت مدرس نور عبدالرسول سلمان ماهینی استادیار دانشکدة محیط زیست دانشگاه علوم کشاورزی و منابع طبیعی گرگان سید محسن حسینی دانشیار گروه جنگلداری دانشکدة منابع طبیعی دانشگاه تربیت مدرس نور فرود آذری دهکردی استادیار گروه برنامه ریزی و مدیریت دانشکدة محیط زیست دانشگاه تهران

forest ecosystems that have spent a long time to mature, offer important goods and services to humanity. hence, utilization and exploitation of these resources should be based on careful assessment of their ecological value and potential. ecological land evaluation is an approach based on land quality, vulnerability and potential assessment for different acceptable uses drawing upon related mod...

Journal: :Proceedings. Biological sciences 2001
C W Dick

Habitat fragmentation is thought to lower the viability of tropical trees by disrupting their mutualisms with native pollinators. However, in this study, Dinizia excelsa (Fabaceae), a canopy-emergent tree, was found to thrive in Amazonian pastures and forest fragments even in the absence of native pollinators. Canopy observations indicated that African honeybees (Apis mellifera scutellata) were...

2015
Dries Verheyen Nele Van Gaelen Benedicta Ronchi Okke Batelaan Eric Struyf Gerard Govers Roel Merckx Jan Diels

Diffuse phosphorus (P) export from agricultural land to surface waters is a significant environmental problem. It is critical to determine the natural background P losses from diffuse sources, but their identification and quantification is difficult. In this study, three headwater catchments with differing land use (arable, pasture and forest) were monitored for 3 years to quantify exports of d...

2001
Rosimeiry Portela Ida Rademacher

This paper presents a dynamic systems model that shows how different land use patterns degrade the value of ecosystem services provided by the Brazilian Amazonia. The model consists of four sectors: (1) deforestation drivers; (2) land use/cover; (3) ecosystem services; and (4) ecosystem valuation. The deforestation drivers sector models the economic and social incentives that small farmers and ...

2013
Maria Baimas-George

Deforestation in the northern highlands of Ethiopia has left 35,000 forest fragments ranging in size from 3 to 300 ha (Bongers et al 2006). Deforestation produces edges which increase disturbance within the forest such as decreased water availability and increased light. To determine the degree of these edge effects and the nutrient status of these forests, I analyzed the nutrient composition o...

Journal: :Revista de biologia tropical 2006
José Luis Martínez-Sáanchez

Environment and seedling community under isolated trees in pastures are different from those in the open pasture. The effect of the pasture trees on the soil nutrients and on the seedling growth were investigated. Seven isolated trees and eight plots were selected in two pastures of 12-yr and 32-yr old derived from a lowland rain forest with nutrient-rich soil at Los Tuxtlas, Mexico. The soil c...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید