نتایج جستجو برای: forest grass cover

تعداد نتایج: 227128  

2007
Felix Eigenbrod Stephen J. Hecnar Lenore Fahrig

Road traffic and the loss of forests are both known to have negative effects on anurans. However, the relative importance of these two predictors is poorly understood because forest cover in the landscape is usually negatively correlated with the density of roads and traffic. To evaluate the independent effects of traffic and forest cover, we selected 36 ponds near Ottawa, Canada, at the center...

2016
Sean Sloan

The tropical deforestation literature advocates multi-agent enquiry in recognition that key dynamics arise from inter-agent interactions. Studies of tropical forest-cover gain have lagged in this respect. This article explores the roles and key aspects of interactions shaping natural forest regeneration and active reforestation in Eastern Panama since 1990. It employs household surveys of agric...

2010
Robert C. Harriss David L. Skole G. Arturo Sánchez-Azofeifa

Accurate estimates of forest cover and forest fragmentation are critical for developing countries such as Costa Rica, which holds four to five percent of the world’s plant and bird species. We estimated forest cover for Costa Rica using Landsat 5 Thematic Mapper satellite scenes acquired between 1986 and 1991. In 1991, 29 percent (ca 14,000 km2) of the land cover of Costa Rica was closed forest...

Journal: :Hydrology and Earth System Sciences 2017

2012
Ivy B. J. Whitehorne Megan L. Harrison Nancy A. Mahony Patrick Robinson David J. Green

Livestock grazing is a dominant land use across North America and although the effects of grazing on birds have been studied in grassland, shrubland, and riparian habitats, studies of the effects in forests are rare. We investigated the effects of cattle grazing in forests on vegetation, the relationships between vegetation characteristics and the abundance of foraging and nesting guilds of bir...

2016
Paul D. Pickell Nicholas C. Coops Sarah E. Gergel David W. Andison Peter L. Marshall

Understanding the development of landscape patterns over broad spatial and temporal scales is a major contribution to ecological sciences and is a critical area of research for forested land management. Boreal forests represent an excellent case study for such research because these forests have undergone significant changes over recent decades. We analyzed the temporal trends of four widely-us...

Journal: :Remote Sensing 2013
Namita Giree Stephen V. Stehman Peter Potapov Matthew C. Hansen

Insular Southeast Asia is a hotspot of humid tropical forest cover loss. A sample-based monitoring approach quantifying forest cover loss from Landsat imagery was implemented to estimate gross forest cover loss for two eras, 1990–2000 and 2000–2005. For each time interval, a probability sample of 18.5 km × 18.5 km blocks was selected, and pairs of Landsat images acquired per sample block were i...

2012
Yady Tatiana Solano Correa Edgar Leonairo Pencue Fierro Apolinar Figueroa

This study presents the implementation of image processing techniques in satellite bands of the visible and infrared spectrum for the differentiation of land cover in the Colombian Andes, which is dominated by high mountain systems, to do this, we extracted features through texture analysis methods, principal component analysis, discrete cosine transform, combination of color spaces and vegetat...

2017
Jian Duan Jie Yang Chongjun Tang Lihua Chen Yaojun Liu Lingyun Wang

Rainfall patterns and land cover are two important factors that affect the runoff generation process. To determine the surface and subsurface flows associated with different rainfall patterns on sloping Ferralsols under different land cover types, observational data related to surface and subsurface flows from 5 m × 15 m plots were collected from 2010 to 2012. The experiment was conducted to as...

Journal: :Nature 1993

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