نتایج جستجو برای: astara forest ecosystem

تعداد نتایج: 179070  

Journal: :Global change biology 2014
Christopher A Williams Melanie K Vanderhoof Myroslava Khomik Bardan Ghimire

Clearcutting and other forest disturbances perturb carbon, water, and energy balances in significant ways, with corresponding influences on Earth's climate system through biogeochemical and biogeophysical effects. Observations are needed to quantify the precise changes in these balances as they vary across diverse disturbances of different types, severities, and in various climate and ecosystem...

2015
Anatoly Shvidenko Dmitry Schepaschenko Sabine Fuss Florian Kraxner Michael Obersteiner

Prerequisites of a system methodology of evaluation of carbon sequestration service of forests (CSS) inter alia include: 1) need of assessment of the CSS in biophysical terms, in form of the Full Verified Carbon Account (FCA); 2) an ultimate proxy indicator of the FCA is Net Ecosystem Carbon Budget of forest ecosystems (NECB); 3) need of explicit spatio-temporal distribution of the service (in ...

2007
Peter Eliasson

Eliasson, P.E. 2007. Impacts of climate change on carbon and nitrogen cycles in boreal forest ecosystems. Doctor’s dissertation. ISSN: 1652-6880, ISBN: 978-91-576-7388-6 It is well known that soil carbon stocks decrease considerably in response to soil warming, but experimental data have shown that the loss of carbon declines within decades in apparent acclimation. An explanation to such findin...

2015
Nick M. Haddad Lars A. Brudvig Jean Clobert Kendi F. Davies Andrew Gonzalez Robert D. Holt Thomas E. Lovejoy Joseph O. Sexton Mike P. Austin Cathy D. Collins William M. Cook Ellen I. Damschen Robert M. Ewers Bryan L. Foster Clinton N. Jenkins Andrew J. King William F. Laurance Douglas J. Levey Chris R. Margules Brett A. Melbourne A. O. Nicholls John L. Orrock Dan-Xia Song John R. Townshend

We conducted an analysis of global forest cover to reveal that 70% of remaining forest is within 1 km of the forest's edge, subject to the degrading effects of fragmentation. A synthesis of fragmentation experiments spanning multiple biomes and scales, five continents, and 35 years demonstrates that habitat fragmentation reduces biodiversity by 13 to 75% and impairs key ecosystem functions by d...

2012
Vladimir Novotny

Background and purpose: It is possible to monitor and study the natural growth and development of the forest ecosystems in the example of protected forest stands, which were excluded from management, and which are not under a negative influence of human activity. Therefore the aim of the research through the repeated measurements is to estimate the stand structure development on the Medveđak pe...

2008
Hui Wang Changgui Wan Jizhou Ren

The regional hydrology and ecosystems of the northeastern margin of the Qinghai–Tibetan Plateau have changed over the past 40 years driven by intense human activity and regional climate changes. Annual mean air temperature has increased in the region. Streamflow from the northeastern margin of the Qinghai–Tibetan Plateau has decreased significantly. Overall, a number of Alpine step meadows and ...

2013
Joseph L. Ganey Scott C. Vojta

Down logs provide important ecosystem services in forests and affect surface fuel loads and fire behavior. Amounts and kinds of logs are influenced by factors such as forest type, disturbance regime, forest management, and climate. To quantify potential short-term changes in log populations during a recent globalclimate-change type drought, we sampled logs in mixed-conifer and ponderosa pine (P...

Journal: :Ecology 2010
Shilong Piao Sebastiaan Luyssaert Philippe Ciais Ivan A Janssens Anping Chen Chao Cao Jingyun Fang Pierre Friedlingstein Yiqi Luo Shaopeng Wang

Forest autotrophic respiration (R(a)) plays an important role in the carbon balance of forest ecosystems. However, its drivers at the global scale are not well known. Based on a global forest database, we explore the relationships of annual R(a) with mean annual temperature (MAT) and biotic factors including net primary productivity (NPP), total biomass, stand age, mean tree height, and maximum...

1998
James M. Guldin T. Bently Wigley

Over the past five years, the public and private sectors have debated the future of forest management and its implications for the next century. In the public sector, resource managers have debated the meaning and significance of “ecosystem management,” a term coined in I992 by then-Forest Service Chief F. Dale Robertson; he suggested that this approach to forest management would “blend the nee...

Journal: :Environmental monitoring and assessment 2007
Ren-Qiang Li Ming Dong Jian-Yong Cui Li-Li Zhang Qing-Guo Cui Wei-Ming He

Pingbian Miao Autonomous County is one of the poorest rural areas in China. Land-use changes, mainly driven by agricultural expansion and deforestation, may significantly impact ecosystem services and functions, but such effects are difficult to quantify. In the present study, Landsat image data were combined with the published coefficients about the world and China ecosystem to quantify land-u...

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