نتایج جستجو برای: subalpine rangeland
تعداد نتایج: 4050 فیلتر نتایج به سال:
To reduce dependence on foreign oil reserves, there has been a push in North America to develop alternative domestic energy resources. Relatively undeveloped renewable energy resources include biofuels and wind and solar energy, many of which occur predominantly on rangelands. Rangelands are also key areas for natural gas development from shales and tight sand formations. Accordingly, policies ...
A long standing question in range management concerns the relative importance of the stocking rate versus the length of time during which animals graze a particular rangeland. We address this question by analyzing the problem faced by a private rancher who wishes to minimize the long run expected net unit cost from range operations by choosing either the stocking rate or the length of time duri...
Comparison of Vegetation Characteristics under Three Management Treatments (Heavy Grazing, Exclusure and with Restoration Practices) in Kiasar Chardange Rangeland Sari
12 [1] We investigated how the source and chemical character of aquatic dissolved organic 13 carbon (DOC) change over the course of the runoff season (May–November, 1999) in 14 Green Lakes Valley, a high-elevation ecosystem in the Front Range of the Colorado Rocky 15 Mountains. Samples were collected on North Boulder Creek from four sites across an 16 alpine/subalpine ecotone in order to unders...
Paleoecological reconstructions using lake sediments provide important information about ecological dynamics and forest disturbance processes that occurred prior to the historic period of scientific observation. In high-altitude and high-latitude ecosystems where landscape-scale disturbances recur at time intervals exceeding observation in many regions, e.g. western North America, reconstructed...
Cypripedium tibeticum, a subalpine orchid species, inhabits various habitats of subalpine forests, mainly including the forest edge (FE), forest gap (FG), and understory (UST), which have significantly different light intensities (FE > FG > UST). However, the ecological and physiological influences caused by different light regimes in this species are still poorly understood. In the present stu...
BACKGROUND Forecasting the effects of global changes on high altitude ecosystems requires an understanding of the long-term relationships between biota and forcing factors to identify resilience thresholds. Fire is a crucial forcing factor: both fuel build-up from land-abandonment in European mountains, and more droughts linked to global warming are likely to increase fire risks. METHODS To a...
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