Jack A. Morgan is plant physiologist and Feike Dijkstra is post-doc research ecologist at the Rangeland Resources Research Unit, Ronald F. Follett is research leader and soil scientist and Stephen Del Grosso is a soil scientist and ecologist at the Soil Plant Nutrient Research Unit, USDA Agricultural Research Service Northern Plains Area, Fort Collins, Colorado. Leon Hartwell Allen Jr. is soil ...

The current growing body of evidence for diversity-disturbance relationships suggests that the peaked pattern predicted by the intermediate disturbance hypothesis (IDH) may not be the rule. Even if ecologists could quantify the diversity-disturbance relationship consistent with the IDH, the applicability of the IDH to land management has rarely been addressed. We examined two hypotheses related...

the “Three-River Headwaters” region (TRHR) rangeland ecosystem is extremely sensitive and fragile, and in recent years has undergone continuous degradation. The vast area and severe nature conditions inhibit data acquisition and field experiments, resulting in different understandings about the spatial characteristics and dynamics of rangeland degradation in the region. Therefore, reliable moni...

G ecosystems cover 30% to 40% of the earth’s terrestrial surface, provide critical habitat for large numbers of species, and support extensive grazing economies on every continent except Antarctica (Coupland 1979, Samson and Knopf 1996). In the United States alone, there are approximately 312 million hectares of rangeland (NRC 1994). Fire, grazing, and climate combine to act as the primary ecos...

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...

mountainous rangeland ecosystems have a highly delicate position in ecologic areabecause of severe environmental conditions and having wildlife and livestock. knowing andrealizing the biotic and abiotic components, which have an interaction with each other in thisecosystem, perform the most important role in to desirable management of it. the systematicmanagement is one of the managing features...

Evaluation of range conditions and plant diversity circumstances can help to rangeland managers who establish their managerial approaches on the basis of ecological capabilities of rangeland ecosystems. Hence, surveying of rangelands was done in four sites of northern Alborz Mt. including western Alborz (Masooleh site), west to middle Alborz (Javaherdeh site), central area (Polour site), and ea...

species diversity is one of the important characteristics shows rangeland ecosystems changes, which isalready under effects of management practices. thus, this research was conducted to study speciesdiversity variation and assess suitable distributive abundance model in three rangeland sites in westazerbaijan. these sites were almost similar in environmental properties and differ in view point ...

CARMA is an advisory system for rangeland grasshopper infestations that demonstrates how AI technology can deliver expert advice to compensate for cutbacks in public services. CARMA uses two knowledge sources for the key task of predicting forage consumption by grasshoppers: (1) cases obtained by asking a group of experts to solve representative hypothetical problems and (2) a numeric model of ...