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421.
TYLER A. CAMPBELL DAVID B. LONG BRUCE R. LELAND 《The Journal of wildlife management》2010,74(2):337-341
ABSTRACT Feral swine (Sus scrofa) impact resources through their destructive feeding behavior, competition with native wildlife, and impacts to domestic animal agriculture. We studied aerial gunning on feral swine to determine if aerial gunning altered home range and core area sizes, distances between home range centroids, and distances moved by surviving individuals. We collected data before, during, and after aerial gunning in southern Texas. Using Global Positioning System collars deployed on 25 adult feral swine at 2 study sites, we found home range and core area sizes did not differ before and after aerial gunning. However, feral swine moved at a greater rate during the aerial gunning phase than during the before and after periods. We concluded that aerial gunning had only minor effects on the behavior of surviving swine and that this removal method should be considered a viable tool in contingency planning for a foreign animal disease outbreak. 相似文献
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423.
TIMOTHY L. CRAWFORD RONALD J. DOBOSY‡ ROBERT T. McMILLEN CHRISTOPH A. VOGEL‡ BRUCE B. HICKS† 《Global Change Biology》1996,2(3):275-285
Strategies to assess long-term atmosphere-ecosystem exchange of CO2 and H2O must deal not only with time trends but also with spatial variability. Flux towers efficiently measure time trends, but only at discrete sites, always limited in number. Representativeness of these sites and the causes of spatial variation between sites are difficult to investigate from tower data alone. Such issues are better addressed with flux measurements from moving vehicles, particularly aircraft. Recent technological advancements in aircraft and instrumentation now allow mobile flux measurement with enhanced precision, greater ease, and lower cost. Results are presented which illustrate the importance of spatial variability, and some suggestions are given for assessment of flux-tower representativeness. Unfortunately, airborne observations of the kind presented here are practical only during a part of the daylight hours in brief intensive field campaigns. Extrapolation of spatial-structure information derived from these measurements to night-time or to long-term averages thus remains problematic. For the foreseeable future this extrapolation will require models that faithfully simulate both space and time characteristics of H2O and CO2 exchange. The development and validation of such models will be greatly enhanced by the increased availability of measurements from moving vehicles, which record spatial as well as temporal structure. 相似文献
424.
Pericarp structure and generic affinities in the Anacardiaceae 总被引:1,自引:0,他引:1
BRUCE S. WANNAN CHRISTOPHER J. QUINN F.L.S. 《Botanical journal of the Linnean Society. Linnean Society of London》1990,102(3):225-252
Pericarp structure is surveyed in 29 genera. Homologous regions termed exocarp, mesocarp and endocarp are established. While exocarp and mesocarp structure show some uniformity, there are two very distinct types of endocarp, designated the Anacardium- type and the Spondias- type . The distribution of these indicates that the current division of the family into five tribes is artificial. The occurrence of the Spondias-type in Canarium , a member of the sister group Burseraceae, suggests that this type is plesiomorphic in the Anacardiaceae. In addition, the presence of the Anacardium- type in Blepharocarya (Blepharocaryaceae) and Orthopterygium Qulianiaceae) further supports the inclusion of these taxa in the Anacardiaceae. 相似文献