نتایج جستجو برای: vegetation density

تعداد نتایج: 453936  

Journal: :Remote Sensing 2015
Jian Peng You Li Lu Tian Yanxu Liu Yanglin Wang

Vegetation is one of the most important components of the terrestrial ecosystem and, thus, monitoring the spatial and temporal dynamics of vegetation has become the key to exploring the basic process of the terrestrial ecosystem. Vegetation change studies have focused on the relationship between climatic factors and vegetation dynamics. However, correlations among the climatic factors always di...

2003
I. Caballero J. M. Olano J. Loidi A. Escudero

The aim of this paper is to evaluate seed bank density and composition along a semi-arid gypsum gradient in Central Spain. Seed bank density was relatively high (16,214 seed/m) with a very clumped spatial distribution. Landform and microslope were the best predictors for seed density, indicating that density can be at least partly interpreted as a result of the physical processes regulating sec...

Journal: :Journal of environmental management 2010
Corinne Lampin-Maillet Marielle Jappiot Marlène Long Christophe Bouillon Denis Morge Jean-Paul Ferrier

Every year, more than 50,000 wildland fires affect about 500,000ha of vegetation in southern European countries, particularly in wildland-urban interfaces (WUI). This paper presents a method to characterize and map WUIs at large scales and over large areas for wildland fire prevention in the South of France. Based on the combination of four types of building configuration and three classes of v...

2014
Matthew B. Russell Anthony W. D’Amato Bethany K. Schulz Christopher W. Woodall Grant M. Domke John B. Bradford

The contribution of understorey vegetation (UVEG) to forest ecosystem biomass and carbon (C) across diverse forest types has, to date, eluded quantification at regional and national scales. Efforts to quantify UVEG C have been limited to field-intensive studies or broad-scale modelling approaches lacking field measurements. Although large-scale inventories of UVEG C are not common, speciesand c...

2013
Ian J Davenport Melody J Sandells Robert J Gurney

The Tau-Omega model of microwave emission from soil and vegetation layers is widely used to estimate soil moisture content from passive microwave observations. Its application to prospective satellite-based observations aggregating several thousand square kilometres requires understanding of the effects of scene heterogeneity. The effects of heterogeneity in soil surface roughness, soil moistur...

2014
Jing Zhang Jianming Niu Alexander Buyantuev Jianguo Wu

Drylands, which occupy more than 40% of the Earth’s land surface, are highly susceptible to degradation. It is important to understand causes, mechanisms, and environmental consequences of dryland ecosystem degradation. Land use policies are known to play a critical role in driving land cover changes, as well as in mitigating land degradation and promoting sustainable development in drylands. W...

The Paliurus spina- christi species grow naturally in three different vegetation regions of Iran (Northern forests, Arsbaran and Zagros forests). But so far no research has been carried out on the sites of this species. Therefore, present study was conducted to investigate the effect of environmental factors on distribution of ecological groups in Paliurus spina- christi site in the Northern fo...

2017
Mingdeng Zhao Zilong Fan

In order to investigate the influence of the vertical variation of porosity on open-channel flow with submerged vegetation, vertical non-homogeneous stumps and stems in submerged vegetation flow are simulated with truncated cones in a laboratory flume. First, porosity is defined as a function of water depth. A new governing equation for vegetation flow is established on the basis of the poroela...

2011
Morgan J. Trimble Rudi J. van Aarde

Previous studies demonstrate that old-growth forest remnants and vegetation regenerating after anthropogenic disturbance provide habitat for birds in a human modified coastal dune forest landscape in northern KwaZulu-Natal, South Africa. However, occurrence does not ensure persistence. Based on a 13-year monitoring database we calculated population trends for 37 bird species and general trends ...

Journal: :Ecology 2008
James B Heffernan

Historically, desert drainages of the American southwest supported productive riverine wetlands (ciénegas). Region-wide erosion of ciénegas during the late 19th and early 20th century dramatically reduced the abundance of these ecosystems, but recent reestablishment of wetlands in Sycamore Creek, Arizona, USA, provides an opportunity to evaluate the mechanisms underlying wetland development. A ...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید