biodiversity plays a crucial role in stability and productivity of natural ecosystem. the main goal of this research was to classify ecological groups in steppe rangeland and investigate their relationships with plant diversity indices. therefore, fifty different land unit tracts (lut) were identified in khod-neuk basin, yazd province, iran, in 2010. vegetation and soil samples were taken in th...

In [HHTZ] the authors characterize the vertex cover algebras which are standard graded. In this paper we give a simple combinatorial criterion for the standard graded property of vertex cover algebras in the case of quasi-trees. We also give an example of how this criterion works and compute the maximal degree of a minimal generator in that case.

Stem density, basal area, vegetation cover and vegetation surface area were compared as measures of the proportions of plant species present in North Okarito Forest, South Westland, for use in determining bird preferences for plant species. In general, stem density estimates of the proportions of canopy species were about 10 times lower than basal area estimates. The converse was true for estim...

Pine straw harvesting con provide on economic benefit to landowners, but the practice may also change the composition of plant communities. This research was initiated in o 34-yeor-old stand of longleaf pine (Pinus palustris Mill.} established in 1956 to study how pine straw management practices (fertilization, prescribed fire, and straw harvesting) affected plant communities, and herein, effec...

Introduction In many circumstances in afforestation, by tree plantation or by direct tree seeding, the quick development of very competitive herbaceous and shrubby species can compromise tree establishment (Balandier et al. 2006). At present, this vegetation is often controlled by chemical and mechanical operations, whereas they are criticized from environmental points of view; some alternative...

Increased livestock densities near artificial watering sites create disturbance gradients called piospheres. We studied responses of alien and native annual plants and native perennial plants within 9 piospheres in the Mojave Desert of North America. Absolute and proportional cover of alien annual plants increased with proximity to watering sites, whereas cover and species richness of native an...

since density is considered as one of the most important numerical indices to explain quantitative values of a plant community by affecting on many aspects and activity of ecosystem, on the other hand, awareness about plants distribution pattern in environment is an essential preparation for measurement and study of vegetative cover, therefore, in this research determination of density and dist...