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41.
The Ring-necked Pheasant ( Phasianus colchicus ) and the Chukar ( Alectoris chukar ) are the dominant avifauna in high-elevation shrubland (2070–3000 m) of Haleakala National Park, Maui, Hawaii. We studied the food habits, ecological niche, and effects of these alien game birds on the native biota in this Hawaiian ecosystem. Analyses of crop contents indicated that pheasant and Chukar consumed predominantly fruits of native, woody dicots (39% and 47% respectively) and leaves (29% and 24% respectively) and flower parts (12% and 17% respectively) of alien, herbaceous dicots. Both species generally selected food items according to their relative availability, although other factors influenced choice of certain items. Invertebrates were a minor component of the game-bird diet, suggesting that their impact on native invertebrate populations is minimal. Pheasant and Chukar occupy, at least partially, an ecological niche once held by now-extinct or rare birds, and they appear not to be significant competitors with the endangered Nene. The role of these alien birds in facilitating seed dispersal and germination of native plant species is beneficial in restoring degraded ecosystems.  相似文献   
42.
We describe a new effort to enhance climate forecast relevance and usability through the development of a system for evaluating and displaying real‐time subseasonal to seasonal (S2S) climate forecasts on a watershed scale. Water managers may not use climate forecasts to their full potential due to perceived low skill, mismatched spatial and temporal resolutions, or lack of knowledge or tools to ingest data. Most forecasts are disseminated as large‐domain maps or gridded datasets and may be systematically biased relative to watershed climatologies. Forecasts presented on a watershed scale allow water managers to view forecasts for their specific basins, thereby increasing the usability and relevance of climate forecasts. This paper describes the formulation of S2S climate forecast products based on the Climate Forecast System version 2 (CFSv2) and the North American Multi‐Model Ensemble (NMME). Forecast products include bi‐weekly CFSv2 forecasts, and monthly and seasonal NMME forecasts. Precipitation and temperature forecasts are aggregated spatially to a United States Geological Survey (USGS) hydrologic unit code 4 (HUC‐4) watershed scale. Forecast verification reveals appreciable skill in the first two bi‐weekly periods (Weeks 1–2 and 2–3) from CFSv2, and usable skill in NMME Month 1 forecast with varying skills at longer lead times dependent on the season. Application of a bias‐correction technique (quantile mapping) eliminates forecast bias in the CFSv2 reforecasts, without adding significantly to correlation skill.  相似文献   
43.
Social network analysis has become a vital tool for studying patterns of individual interactions that influence a variety of processes in behavior, ecology, and evolution. Taxa in which interactions are indirect or whose social behaviors are difficult to observe directly are being excluded from this rapidly expanding field. Here, we introduce a method that uses a probabilistic and spatially implicit technique for delineating social interactions. Kernel density estimators (KDE) are nonparametric techniques that are often used in home range analyses and allow researchers studying social networks to generate interaction matrices based on shared space use. We explored the use of KDE analysis and the effects of altering KDE input parameters on social network metrics using data from a natural population of the spatially persistent forked fungus beetle, Bolitotherus cornutus.  相似文献   
44.
This paper assesses the contribution of land-use planning to the objectives of local sustainable development in some of the UK's most urbanized areas. Sustainable development provides the context within which local planning policies are now being prepared, and can be seen to be a potentially important aspect of central government's proposals for modernizing local government. Using the results from a comprehensive survey of development plans in metropolitan authorities, the paper assesses both the strengths and the weaknesses of land-use planning in terms of sustainable development and speculates upon the lessons they may offer to the government's more recent proposals on modernizing local government.  相似文献   
45.
Abstract: A form of lowland, sandplain Fynbos restricted to the Cape Flats near the city of Cape Town is the South African vegetation type most threatened by urban and agricultural development. Cape Flats Fynbos remnants, totaling 4.8 km2, contain 14 plant species endemic to the Cape Flats scattered through four protected areas and 11 unprotected vegetation fragments on public land. Despite their small size and management problems, the remaining protected areas are under pressure from the public and developers to function as "lifeboats," or places of safety, for attractive indigenous plant species from the unprotected areas destined for development because the popular perception is that any indigenous plant population threatened by habitat destruction should be saved by being transplanted into a protected area. The urgency for dealing with the issue of plant rescue in the Cape Town metropolitan area was the catalyst for a workshop held at the University of Cape Town in 1998 to develop protocols for Fynbos plant species translocations. We report on points raised by managers and academics at the workshop, including the selection of target taxa, individuals, and establishment sites, and methods for introduction, and present case histories illustrating possible solutions to the problems encountered.  相似文献   
46.
Ozone concentrations at a rural-remote site in a forested region of north-central West Virginia were monitored during 1988 and 1989, a drought and wet year, respectively. During 1988, the absolute maximum average concentration for a single hour was 156 ppb, while it was only 107 ppb in 1989. Overall, the frequency of high concentrations was greater during 1988; the 120 ppb National Ambient Air Quality Standard was exceeded 17 times. The 7-h period encompassing the highest growing season concentrations for this site over the 2-yr period is 1100- 1759 h EST, rather than the period 0900-1559 h originally used by the National Crop Loss Assessment Network. The 7-h growing season means (0900-1559 h) of 52.6 ppb and 47.1 ppb for 1988 and 1989, respectively, compare well to those reported for the Piedmont/Mountain/Ridge-Valley area, but are higher than those for other surrounding areas. The diurnal ozone patterns, as well as the distribution of concentration ranges and timing of seasonal maxima, suggest that long-range transport of ozone and its precursors probably is an important factor at this site, given its remote and rural character.  相似文献   
47.
48.
ABSTRACT: Recognition of the flood hazard that exists on alluvial fans has seriously lagged behind the recognition of other more conventional flood hazards such as those associated with most rivers. This delay in recognition was due, until recently, to a general lack of economic investment and development in these areas and a concomitant lack of historical alluvial fan flood damage. Dramatic recent events, such as Tropical Storm Kathleen, emphasized to the Federal Insurance Administration (FIA) the need for developing an appropriate methodology to identify flood hazard areas on alluvial fans. This paper presents the methodology now employed by FIA as well as flood plain management considerations that could reduce future flood related damage to communities developing in these areas.  相似文献   
49.
ABSTRACT: The hydrologic impacts of livestock grazing schemes on selected plant communities and soils at Fort Stanton, New Mexico, were evaluated. Simulated rainfall was applied to 1 m2plots. On a mesa-top, infiltration rates for a grassland livestock exclosure and a pinyon pine-juniper community closely approximated each other and were significantly greater (P = 0.10) than either a moderate continuous or a heavy continuous treatment in a grassland community. Sediment concentration from the heavy continuous treatment was more than twice that of the other treatments. Infiltration rates on the hillside site were highest in a pinyon pine-juniper community receiving short duration grazing. Infiltration for this treatment was found to be significantly higher (P = 0.10) than that of a short duration grazing treatment, but not from a rest rotation grazing treatment on grassland. The short duration grazing treatment on a grassland had the highest sediment concentration, while the rest rotation grazing on a grassland and the short duration pinyon pine-juniper treatments were found to be similar. In the bottomland site, a fertilized and unfertilized treatment showed no significant difference in infiltration or sediment concentration, although twice as many animals were present on the fertilized treatment.  相似文献   
50.
The well-established environmental impact assessment requirements in the United States have given rise to a number of training needs within federal and state agencies. Requirements for training vary for EIA project managers, technical specialists, senior managers and others involved in EIA. Information needs about EIA vary also, but include general awareness, procedural knowledge, substantive methodological knowledge and technical knowledge. While EIA training is provided in short courses, on the job, and in universities there remain deficiencies in the training of specialists, senior managers, and others. Proposals are made here to help overcome these. This paper examines the needs and provisions for training in environmental impact assessment (EIA) in the USA federal system and in the system created by the California Environmental Quality Act. The investigation is based on the very limited literature on training, on responses to letters, on the printed material requested from agencies and, most importantly, on the results of a series of interviews of personnel in various federal agencies at central and regional levels, in California, and elsewhere. A recent report by the Environmental Law Institute (1981) furnished invaluable background information on EIA training in the federal agencies. The list of liaison officers printed by the Council on Environmental Quality (1982a) was used to request interviews and information.  相似文献   
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