growth and productivity of plants are mainly affected by various environmentalfactors in different ecosystems and natural habitat in the world. this research aims to studythe existing relationships between the phytosociology characteristics of thymuskotschyanus and environmental factors in order to find the most important factorsgoverning development of the species in middle taleghan rangelands...

T e influence of pixel heterogeneity, background, atmospheric and bidirectional effects on the relationship between fraction of photosynthetically active radiation absorbed by the photosynthesizing tissue in a canopy (FAPAR) and normalized difference vegetation index (NDVI) is investigated using a three-dimensional model of radiation transfer. Top of the canopy (TOC) NDVI and FAPAR increase wit...

in order to evaluate the effect of cover crops and mulch management on yield and yield components of safflower (carthamus tinctorius l.), a study was conducted as split-plot based on a complete randomized block design with four replications during 2008-2009. the mulch managements as main factor were consisted of three levels including incorporation of cover crops with soil, harvesting + removin...

Although most temperate forests are actively managed for timber production, few data exist regarding the long-term effects of forest management on understory plant communities. We investigated the responses of understory communities to a factorial combination of silvicultural-thinning and nutrient-addition treatments maintained for 12–16 yr in a set of 21–27 yr old Douglas-fir (Pseudotsuga menz...

Management of plant litter or crop residues in agricultural fields is an important consideration for reducing soil erosion and increasing soil organic C. Current methods of quantifying crop residue cover are inadequate for characterizing the spatial variability of residue cover within fields or across large regions. Our objectives were to evaluate several spectral indices for measuring crop res...

Tropical volcanoes are an important but understudied ecosystem, and the relationships between plant species diversity and compositional change and elevation may differ from mountains created by uplift, because of their younger and more homogeneous soils. We sampled vegetation over an altitudinal gradient on Mt. Rinjani, Lombok, Indonesia. We modeled alpha- (plot) and beta- (among plot) diversit...

1 Former human practices can persistently influence forest ecosystems, particularly by altering the distribution and abundance of vegetation. Previous research has focused on the role of colonization success in governing plant community patterns in abandoned forests, but few studies have explored how changes in the performance of adult plants may contribute to changes in plant populations. 2 We...

We used snow fences and small (1m) open-topped fiberglass chambers (OTCs) to study the effects of changes in winter snow cover and summer air temperatures on arctic tundra. In 1994, two 60m long, 2.8m high snow fences, one in moist and the other in dry tundra, were erected at Toolik Lake, Alaska. OTCs paired with unwarmed plots, were placed along each experimental snow gradient and in control a...