نتایج جستجو برای: exclosure
تعداد نتایج: 275 فیلتر نتایج به سال:
Exclosure is considered as a management method to improve vegetation. This study aimed to evaluate the effects of exclosure on species diversity in Zayanderod dam station in Chadegan, Isfahan. The study area was stratified based on the various management types and slope directions, and samples were collected randomly in each layer. Four perpendicular transects, 500m in length were established a...
Recent attitude of vegetation assessors is using of new ecologic approaches to evaluate and analyse the complex rangeland ecosystems. Plant diversity is the most important indices to assess the ecological changes of rangelands. In order to survey of plant indices of rangelands, two exclosure areas (long-term and mid-term) and a grazing area in rangelands of Javaherdeh (Ramsar, Iran) were select...
overgrazing, via harvesting of forage species and decrease the other herbs, is of progressive factors in biodiversity destroying. in order to investigate the animal grazing impacts on changing of plant structure and diversity, we selected the comparison between this effect with exclosure area, and proving of the excluded area effects on plant diversity; two sites of kojour rangeland, mazandran ...
Historical extirpations have resulted in depauperate large herbivore assemblages in many northern forests. In eastern North America, most forests are inhabited by a single wild ungulate species, white-tailed deer (Odocoileus virginianus), and relationships between deer densities and impacts on forest regeneration are correspondingly well documented. Recent recolonizations by moose (Alces americ...
The effects of small-scale disturbances (80 30-cm plots) of canopy and grazers on intertidal assemblages were investigated in this 4-year experiment on sheltered rocky shores on the Swedish west coast. Canopy disturbances due to ice scouring were mimicked by removal of adult plants of the seaweed Ascophyllum nodosum (L.) Le Joli. Density of the main epilithic grazing gastropods, Littorina spp.,...
Grassland degradation in the Inner Mongolia grassland became seriously since the end of 20th century, because of the rapid expansion of livestock numbers and the development of economy. Overgrazing in this region is one of the main causes of grassland degradation. In this paper, soil microbial biomass carbon (Cmic) and nitrogen (Nmic) under continuous free-grazing and exclusion of livestock wer...
Exotic plant invasions and chronic high levels of herbivory are two of the major biotic stressors impacting temperate forest ecosystems in eastern North America, and the two problems are often linked. We used a 4-ha deer exclosure maintained since 1991 to examine the influence of a generalist herbivore, white-tailed deer (Odocoileus virginianus), on the abundance of four exotic invasive (Rosa m...
It is still not well established whether plant chemical and physical defence traits can be simultaneously induced in savanna trees how this would affect nutritional quality. Here, we use a long-term mammalian herbivore exclosure experiment dystrophic semi-arid African to test (condensed tannins [CTs] total polyphenols [TPs]) structural (spines thorns) defences are affected by exclusion five com...
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