نتایج جستجو برای: forest floor vegetation

تعداد نتایج: 175675  

2007
Kathleen M. Bergen Kathleen Bergen Amy M. Gilboy Daniel G. Brown

Article history: Received 31 December 2006 Accepted 2 January 2007 RR EC TE D PR O The goal of this study was to evaluate the contributions of forest and landscape structure derived from remote sensing instruments to habitatmapping. Our empirical data focused at the landscape scale on a test site in northern Michigan, using radar and Landsat imagery and bird-presence data by species. We tested ...

2011
Coeli M Hoover

BACKGROUND The role of forests in the global carbon cycle has been the subject of a great deal of research recently, but the impact of management practices on forest soil dynamics at the stand level has received less attention. This study used six forest management experimental sites in five northern states of the US to investigate the effects of silvicultural treatments (light thinning, heavy ...

2010
David A. Swayne Wanhong Yang A. A. Voinov

In recent years, forest fires frequency and intensity has increased, causing a new awareness about their impact not only on vegetation, but also on hydrological regime. Changes in vegetation influence the processes of interception and evapotranspiration, seriously affecting the hydrological cycle. Forest fires can also affect hydrological processes indirectly, altering the hydraulic properties ...

Journal: :Photogrammetric engineering and remote sensing 2008
Dengsheng Lu Mateus Batistella Emilio Moran

Traditional change detection approaches have been proven to be difficult in detecting vegetation changes in the moist tropical regions with multitemporal images. This paper explores the integration of Landsat Thematic Mapper (TM) and SPOT High Resolution Geometric (HRG) instrument data for vegetation change detection in the Brazilian Amazon. A principal component analysis was used to integrate ...

Wildfires are of the forest-related disasters caused by inhumane factors.  Spreading of these fires is due to the increase of the density of flammable plants. Two important approaches to prevent this occurrence are fuel treatment and fire suppression resources preparedness. In this paper, a mixed integer programming model is proposed based on the covering location and assignment problems which ...

Journal: :PLoS ONE 2009
Maj-Britt Pontoppidan Winanda Himaman Nigel L. Hywel-Jones Jacobus J. Boomsma David P. Hughes

Parasites are likely to play an important role in structuring host populations. Many adaptively manipulate host behaviour, so that the extended phenotypes of these parasites and their distributions in space and time are potentially important ecological variables. The fungus Ophiocordyceps unilateralis, which is pan-tropical in distribution, causes infected worker ants to leave their nest and di...

2000
Dennis D. Baldocchi Beverly E. Law Peter M. Anthoni

Information on mass and energy exchange at the soil surface under vegetation is a critical component of micrometeorological, climate, biogeochemical and hydrological models. Under sparse boreal and western conifer forests as much as 50% of incident solar energy reaches the soil surface. How this energy is partitioned into evaporating soil moisture, heating the air and soil remains a topic of sc...

2015
Diane De Steven Stephen P. Faulkner Bobby D. Keeland Michael J. Baldwin John W. McCoy Steven C. Hughes

In the Mississippi River Alluvial Valley (MAV), complete alteration of river-floodplain hydrology allowed for widespread conversion of forested bottomlands to intensive agriculture, resulting in nearly 80% forest loss. Governmental programs have attempted to restore forest habitat and functions within this altered landscape by the methods of tree planting (afforestation) and local hydrologic en...

2014
Jay Ruffell Raphael K. Didham Paul Barrett Nic Gorman Rhonda Pike Andrée Hickey-Elliott Karin Sievwright Doug P. Armstrong

Forest edges can strongly affect avian nest success by altering nest predation rates, but this relationship is inconsistent and context dependent. There is a need for researchers to improve the predictability of edge effects on nest predation rates by examining the mechanisms driving their occurrence and variability. In this study, we examined how the capture rates of ship rats, an invasive nes...

2014
Qiongyu Huang Anu Swatantran Ralph Dubayah Scott J. Goetz

Avian diversity is under increasing pressures. It is thus critical to understand the ecological variables that contribute to large scale spatial distribution of avian species diversity. Traditionally, studies have relied primarily on two-dimensional habitat structure to model broad scale species richness. Vegetation vertical structure is increasingly used at local scales. However, the spatial a...

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