نتایج جستجو برای: canopy cover
تعداد نتایج: 122030 فیلتر نتایج به سال:
We analyse spatial variability and different evolution patterns of snowpack in a mixed beech–fir stand in the central Pyrenees. Snow depth and density were surveyed weekly along six transects of contrasting forest cover during a complete accumulation and melting season; we also surveyed a sector unaffected by canopy cover. Forest density was measured using the sky view factor (SVF) obtained fro...
Predicting the effects of global climate change on species interactions has remained difficult because there is a spatiotemporal mismatch between regional climate models and microclimates experienced by organisms. We evaluated resource selection in a predominant ectothermic predator using a modeling approach that permitted us to assess the importance of habitat structure and local real-time air...
Although they are important components of forest communities, the general ecology and spatiotemporal patterns of temperate lianas during forest regeneration are largely unknown. The dependence of lianas on other plants for physical support makes them a potentially important driver of community dynamics. We examined 50 years of vegetation data from an old-field succession study to determine the ...
Testing the influence of local forest canopy clearing on phenotypic variation in Trinidadian guppies
1. Factors contributing to the maintenance of phenotypic variation in nature are often difficult to determine. Secondary sexual traits might be particularly interesting in this regard due to the interaction they experience between multiple selective agents. One way to examine such effects is to monitor populations following environmental change. Human-caused changes can be particularly useful h...
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...
Forested ecosystems in the southeastern United States are currently undergoing an invasion by the hemlock woolly adelgid (HWA). Previous studies in this area have shown changes to forest structure, decreases in canopy cover, increases in organic matter, and changes to nutrient cycling on the forest floor and soil. Here, we were interested in how the effects of canopy loss and nutrient leakage f...
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...
Airborne lidar (light detecting and ranging) is a useful tool for probing the structure of forest canopies. Such information is not readily available from other remote sensing methods and is essential for modern forest inventories. In this study, small-footprint lidar data were used to estimate biophysical properties of young, mature, and old cottonwood trees in the San Pedro River basin near B...
Two demonstration sites in southeast Idaho, USA were used to extend remote sensing of leafy spurge research to fine-scale detection for abundance mapping using matched filtering (MF) scores. Linear regression analysis was used to quantify the relationship between MF estimates and calibrated ground estimates of leafy spurge abundance. The two sites had r values of 0.46 and 0.64. Both the slope o...
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