Humans are rapidly altering natural systems, leading to changes in the distribution and abundance of species. However, so many changes are occurring simultaneously (e.g., climate change, habitat fragmentation) that it is difficult to determine the cause of population fluctuations from correlational studies. We used a manipulative field experiment to determine whether forest canopy cover directl...

The desirable structure of longleaf pine forests, which generally includes a relatively open canopy of pines, very few woody stems in the mid-story, and a well-developed, herbaceous ground layer, provides critical habitat for flora and fauna and contributes to ecosystem function. Current efforts to restore longleaf pine to upland sites dominated by second-growth loblolly pine require informatio...

Wildfires can create or intensify water repellency in soil, limiting the soil's capacity to wet and retain water. The objective of this research was to quantify soil water repellency characteristics within burned piñon-juniper woodlands and relate this information to ecological site characteristics. We sampled soil water repellency across forty-one 1,000 m2 study plots within three major wildfi...

Ecosystems may shift abruptly between alternative states in response to environmental perturbations. Early warning indicators have been proposed to anticipate such regime shifts, but experimental field tests of their validity are rare. We exposed rocky intertidal algal canopies to a gradient of press perturbations and recorded the response of associated assemblages over 7 years. Reduced cover a...

in order to evaluate capability of the landsat-etm and irs-p6-liss iv images for canopy cover mapping a case study was done on the forests of javanroud in kermanshah province. after evaluation of the geometric and radiometric quality of the data, the etm+ images, the etm+ images were geometrically corrected with gcps and the images were registered with rmse error 0.46 and 0.48 pixels, for x and...

plants cover composition, condition, trend, production, and grazing capacity of the rangeland change annually. in this research, the role of temporal rainfall distribution on rangeland production was assessed. this research had down in the rangelands of ilam (with semiarid to semi humid climate) and qom and markazi (with arid to semiarid climate) provinces. by attention on plant cover maps in e...

We used a predictive model to map canopy cover of vegetation over seven feet in height (“tall woody vegetation”) at 30-meter resolution over nearly 29 million acres within and adjacent to the range of the greater sage-grouse in Oregon (Figure 1). Texture measures computed at various resolutions from colorinfrared aerial photography provided the main source of predictor data used to produce the ...

T h e effect of variable tree canopy cover, shadows, and topography on Thematic Mapper (TM) data was examined for blue oak (Quercus douglasii) woodland and wooded grassland on rugged terrain in central California. Thematic Mapper data were analyzed from September 1986 (trees in leaf, grass understory senescent) and December 1984 (trees leafless, grasses emerging. Tree cover measured in 84 60 m ...