جستجوی مقالات مرتبط با کلیدواژه "ecological indicator" در نشریات گروه "منابع طبیعی"

Punctual assessment of rangeland health is essential for detection of occurred alterations in biotic and abiotic components of rangeland ecosystems. This study aimed to assess rangeland condition in Gremi, Ardabil Province, northern Iran in three methods, i.e., four-factor, six-factor and rangeland health indicators; also it was aimed to designate the best method by analyzing the accuracy and precision of methods. Three exclosures (reference sites) and three range sites under continuous grazing (evaluation sites) adjacent to them were selected. Some attributes of vegetation and soil e.g. canopy cover, bare soil and liter percent were measured on transect lines (50 m) and quadrats (1×1.5m). In rangeland health indicators method, indicators of reference site were firstly evaluated and then the departure degree of evaluation site (grazed rangeland) from reference site was scored. The health of all exclosures and grazed rangelands were categorized ‘good’ and ‘poor’, respectively, by both four-factor and six-factor methods. Departure degree of most indicators from reference site was moderate to extreme in evaluation sites 1 and 2. These sites were marked ‘unhealthy’. The departure degree of evaluation site 3 from reference site was moderate, then, this site was marked ‘at risk’. Accuracy and precision level of four-factor method was greater than those in six-factor method. Consequently, four-factor method was found as appropriate method for assessment of rangeland condition (health) in Gremi. In the case that the aim of rangeland health assessment is to make decision about important issues of management and the reference site is available, we recommend the use of rangeland health indicators method.