77 research outputs found

    An Ecological Basis for Ecosystem Management

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    This report was prepared by the Southwestern Regional Ecosystem Management Study Team composed of management and research biologists. The USDA Forest Service Southwestern Regions Regional Forester, Larry Henson, and the Rocky Mountain Forest and Range Experiment Station Director, Denver Burns, chartered this team to recommend an ecological basis for ecosystem management. This report is not intended to provide details on all aspects of ecosystem management; it simply provides information and makes recommendations for an ecological basis for ecosystem management. The report is not a decision document. It does not allocate resources on public lands nor does it make recommendations to that effect. The report of this Study Team may be relied upon as input in processes initiated under the National Environmental Policy Act (NEPA), National Forest Management Act (NFMA), Endangered Species Act (ESA), Administrative Procedures Act (APA), and other applicable laws. The information contained in this report is general in nature, rather than site specific. Implementation of ecosystem management and allocation of resources on Forest Service administered lands is the responsibility of the National Forest System in partnership with Forest Service Research and State and Private Forestry. Implementation is done through Forest and project plans that are subject to the NEPA process of disclosing the effects of proposed actions and affording the opportunity for public comment. The Southwestern Region follows a planning process for projects called Integrated Resource Management (IRM). The opinions expressed by the authors do not necessarily represent the policy or position of the U.S. Department of Agriculture, the Forest Service, The Nature Conservancy, or the Arizona Game and Fish Department. The Study Team acknowledges the valuable input of more than 50 individuals from various agencies, universities, professional organizations, and other groups who provided thoughtful comments of an earlier draft of this document. Some of their comments are included in Appendix 3

    Management recommendations for the northern goshawk in the southwestern United States

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    Present forest conditions--loss of a herbaceous and shrubby understory, reductions in the amount of older forests, and increased areas of dense tree regeneration--reflect the extent of human influence on these forests. These changes may also be affecting goshawk populations. Information on goshawk nesting habitat and foraging behavior, and the food and habitats of selected goshawk prey, was therefore synthesized to develop a set of management objectives, desired forest conditions, and management recommendations. Key objectives of the guidelines are to provide (1) nesting, post-fledging, and foraging areas for goshawks, and (2) habitat to support abundant populations of 14 primary goshawk prey. Thinning trees in the understory, creating small openings in the forest, and prescribed fires should help produce and maintain the desired forest conditions. Other habitat elements critical for maintaining both goshawk and prey populations include abundant snags and large downed logs, woody debris, interspersion of different tree sizes across the landscape, and the majority of a goshawk's home range in older-aged forests. These guidelines should also benefit forest health, soil productivity, and the habitats of other old-growth dependent plants and animals

    The epitaxy of gold

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    Oxygen Isotopic Composition of Biogenic Phosphate and the Temperature of Early Ordovician Seawater

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    Stable isotopic values were measured on micrite, sparry calcite, dolomite, inarticulated brachiopods, and conodonts from the Lange Ranch section (central Texas) of the Lower Ordovician Tanyard Formation. The section spans the upper Cordylodus angulatus Zone through the lower Rossodus manitouensis Zone. An ∼2‰ negative δ13C shift from \u3c0‰ to \u3c−1.5‰VPDB through the section suggests the lower third of the Rossodus manitouensis Zone was sampled. Consistent with previous studies, the δ18O values of carbonates are low, ranging from −3.3‰ to −8.1‰VPDB. Phosphate δ18O values range from 15.4‰ to 17.1‰VSMOW. Paleotemperature estimates calculated from micrite δ18O values assuming an ice-free seawater δ18O value of −1‰VSMOW indicate Early Ordovician tropical seawater temperatures averaged 42°C, whereas δ18O values of co-occurring biogenic phosphate assuming the same seawater value yield paleotemperature estimates averaging 37°C. The phosphate values are interpreted as less affected by diagenesis than carbonate values and suggest Early Ordovician tropical paleotemperatures were not more than 10°C warmer or the oxygen isotopic composition of Early Ordovician hydrosphere was not more than 2‰ lower than present
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