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71.
MÔNICA B. HARRIS†† WALFRIDO TOMAS† GUILHERME MOURÃO† CAROLINA J. DA SILVA‡ ERIKA GUIMARÃES FÁTIMA SONODA§ ELIANI FACHIM§ 《Conservation biology》2005,19(3):714-720
Abstract: The Pantanal, one of the largest wetlands on the planet, comprises 140,000 km2 of lowland floodplain of the upper Rio Paraguai basin that drains the Cerrado of central Brazil. The diverse mosaics of habitats resulting from the varied soil types and inundation regimes are responsible for an extraordinarily rich terrestrial and aquatic biota, exemplified by the bird richest wetland in the world—463 birds have been recorded there—and the largest known populations of several threatened mammals, such as Pampas deer ( Ozotoceros bezoarticus ), marsh deer ( Blastocerus dichotomus ), giant otter ( Pteronura brasiliensis ), and jaguar ( Panthera onca ). Until recently, deforestation of the adjoining Brazilian central plateau was considered the major threat to this area, but now deforestation is a critical problem within the floodplain itself. More than 40% of the forest and savanna habitats have been altered for cattle ranching through the introduction of exotic grasses. And there are other threats that lead to large-scale disruption of ecological processes, severely affecting biodiversity. Although the Pantanal wetland is a Biosphere Reserve and is considered a Wetland of International Importance, only 2.5% of the upper Paraguai River basin is formally protected. To date, protected areas have been created opportunistically and as such, although of undoubted value, protect only a fraction of the Pantanal's wildlife and habitats. Among the conservation initiatives in the area, the private sector is increasingly participating in the establishment of private reserves. The prospects are far from optimistic, however, and the major challenge is to find alternative socioeconomic models that allow for conservation and economic uses of the land in association with the development of specific environmental legislation that reflects the unique characteristics of the region. 相似文献
72.
73.
PAULO M. MARTINS DA COSTA PAULO M. VAZ-PIRES FERNANDO M. BERNARDO 《Journal of environmental science and health. Part. B》2013,48(8):1393-1403
Antibiotimicrobial resistance was investigated in 537 Enterococcus spp. isolates recovered from 22 samples of crude inflow, treated effluent and sludge collected in wastewater treatment plants of eight poultry slaughterhouses of Portugal. No significant differences (P > 0.05) were found in the resistance to each antimicrobial agent with regards to the origin of the sample (inflow, sludge and effluent). Many of the isolates displayed resistance to tetracycline (85.7%), erythromycin (45.7%), nitrofurantoin (34.0%) and rifampicin (17.8%). Resistance was also observed, but to a lesser extent, to ciprofloxacin (10.2%), ampicillin (8.0%), chloramphenicol (4.6%), vancomycin (0.9%) and gentamicin (0.4%). Resistance to three or more antimicrobial classes was present in 37.1% of the isolates. Wastewater treatment resulted in viable enterococci decrease between less than 1 log and 4 log; nevertheless, more than 4.4 × 105 colony forming units (CFU)/100 mL were present in the outflow of the plants and thus resistant enterococci are not prevented from reaching the general environment. 相似文献
74.
Connectivity of wood thrush breeding,wintering, and migration sites based on range‐wide tracking
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Calandra Q. Stanley Emily A. McKinnon Kevin C. Fraser Maggie P. Macpherson Garth Casbourn Lyle Friesen Peter P. Marra Colin Studds T. Brandt Ryder Nora E. Diggs Bridget J. M. Stutchbury 《Conservation biology》2015,29(1):164-174
Many migratory animals are experiencing rapid population declines, but migration data with the geographic scope and resolution to quantify the complex network of movements between breeding and nonbreeding regions are often lacking. Determining the most frequently used migration routes and nonbreeding regions for a species is critical for understanding population dynamics and making effective conservation decisions. We tracked the migration of individual Wood Thrushes (Hylocichla mustelina) (n = 102) from across their range with light‐level geolocators and, for the first time, quantified migration routes and wintering regions for distinct breeding populations. We identified regional and species‐level migratory connectivity networks for this declining songbird by combining our tracking results with range‐wide breeding abundance estimates and forest cover data. More than 50% of the species occupied the eastern wintering range (Honduras to Costa Rica), a region that includes only one‐third of all wintering habitat and that is undergoing intensive deforestation. We estimated that half of all Wood Thrushes in North America migrate south through Florida in fall, whereas in spring approximately 73% funnel northward through a narrow span along the central U.S. Gulf Coast (88–93°W). Identifying migratory networks is a critical step for conservation of songbirds and we demonstrated with Wood Thrushes how it can highlight conservation hotspots for regional populations and species as a whole. Conectividad de Sitios de Reproducción, Invierno y Migración del Zorzal con Base en Rastreo de Cobertura Amplia 相似文献
75.
A.F. Fraser 《Agriculture, ecosystems & environment》1983,9(1):1-23
A major feature of our living environment consists of the domesticated animals. As their use intensifies so too does the obligation to them — and to their basic life practices — which we acquired at the moment of their domestication. Much of the behaviour of farm animals is concerned with self-maintenance, indeed, highly successful self-maintenance is the basis of animal productivity. Activities involved in such maintenance appear to fall into eight primary categories. These are basically of innate origin and include much instinctive behaviour. The use of these behaviours of reactivity, ingestion, exploration, movement, association, body care, territorialism and rest are vital to the animal in its integration and mediation with its environment. Within these eight primary systems of behaviour, numerous specific behaviours are exhibited in natural free-ranging conditions. Cattle exhibit 44 specific behaviours related to maintenance; sheep have 43 and pigs show 48. All of these above behaviours require environmental facility and where this is deficient, deficits occur in behaviour.Ethological deficits have been determined for methods of husbandry relating to the intensive production of calves, steers, sheep and pigs. Veal calves had 25 behavioural deficits, feedlot cattle had 11, housed sheep had 13 and enstalled swine had 26. These figures give indices of behavioural deprivation ranging from 25% in feedlot cattle to 56% in veal calves in stalls.Anomalous behaviour is now increasingly seen among animals which are managed under close confinement; restricted accommodation in an essentially featureles environment. Much of the anomalous behaviour which has been investigated is found to be the result of aversive environments. Anomalous behaviours are typically found in those forms of husbandry which involve intense grouping of animals and also a lack of what might be termed diversionary facilities in their environment. Reduced input of environmental stimulation and opportunity is evidently capable of acting with adverse effect on functional mediation, so as to generate anomalous forms of behaviour such as “orosthenia” — pathological oral activity. Such abnormal behaviour serves as a symptom of confinement stress. In animal production the application of ethology can provide a monitoring operation for livestock care to ensure welfare and ethological entitlement. 相似文献
76.
Summary Populations of guppies, Poecilia reticulata and Hart's rivulus, Rivulus harti, in Trinidad experience different levels of predation hazard from piscivorous fish. Those from the larger rivers (downstream sites) experience chronically high predation hazard, while those from headwater streams (upstream sites) have few predators. Guppies and Hart's rivulus, collected from downstream and upstream sites, were assayed for their feeding rate in the presence and absence of predators. We defined tenacity as the ratio of the feeding rates in the presence and absence of a predator stimulus. Thus, tenacity expresses the degree to which the forager maintains its feeding rate when a predator stimulus is present. Previous work by Seghers (1973) showed that non-feeding guppies from downstream sites responded more strongly to predators than did guppies from upstream sites. Based on this, we initially hypothesized that fish from downstream sites would show lower tenacities than fish from upstream sites. However, we found the opposite in every case. When confronted with a predator stimulus, guppies and Hart's rivulus from downstream sites fed at consistently greater rates and displayed greater tenacities than did those from upstream sites. These differences were found in experiments using both live and model predators. The results suggest that upstream fish readily trade off feeding for hiding and avoiding predation hazard, a likely response when predators appear infrequently, while downstream fish appear to be selected for boldness and tenacity while foraging under chronically high hazard. 相似文献
77.
Armed sibling rivalry among suckling piglets 总被引:3,自引:2,他引:1
Summary A piglet's most precious possession Is the teat that he fattens his flesh on. He fights for his teat with tenacity Against any sibling's audacity. The piglet, to arm for this mission, Is born with a warlike dentition Of eight tiny tusks, sharp as sabres, Which help in impressing the neighbors; But to render these weapons less harrowing, Most farmers remove them at farrowing. We studied pig sisters and brothers When some had their teeth, but not others. We found that when siblings aren't many, The weapons help little if any, But when there are many per litter, The teeth help their owners grow fitter. But how did selection begin To make weapons to use against kin?
Offprint requests to: D. Fraser 相似文献
78.
79.
Robert H. Fraser Maureen V. Warren Paul K Barten 《Journal of the American Water Resources Association》1995,31(6):991-1000
ABSTRACT: A fundamental problem in protecting surface drinking water supplies is the identification of sites highly susceptible to soil erosion and other forms of nonpoint source (NPS) pollution. The New York City Department of Environmental Protection is trying to identify erodible sites as part of a program aimed at avoiding costly filtration. New York City's 2,000 square mile watershed system is well suited for analysis with geographic information systems (GIS); an increasingly important tool to determine the spatial distribution of sensitive NPS pollution areas. This study used a GIS to compare three land cover sources for input into the Modified Universal Soil Loss Equation (MUSLE), a model estimating soil loss from rangeland and forests, for a tributary watershed within New York City's water supply system. Sources included both conventional data (aerial photography) and Landsat data (MSS and TM images). Although land cover classifications varied significantly across these sources, location-specific and aggregate watershed predictions of the MUSLE were very similar. We conclude that using Landsat TM imagery with a hybrid classification algorithm provides a rapid, objective means of developing large area land cover databases for use in the MUSLE, thus presenting an attractive alternative to photo interpretation. 相似文献
80.
Decision Support for Road System Analysis and Modification on the Tahoe National Forest 总被引:1,自引:0,他引:1
The United States Forest Service is required to analyze road systems on each of the national forests for potential environmental impacts. We have developed a novel and inexpensive way to do this using the Ecosystem Management Decision Support program (EMDS). We used EMDS to integrate a user-developed fuzzy logic knowledge base with a grid-based geographic information system to evaluate the degree of truth for assertions about a roads environmental impact. Using spatial data for natural and human processes in the Tahoc National Forest (TNF, California, USA), we evaluated the assertion the road has a high potential for impacting the environment. We found a high level of agreement between the products of this evaluation and ground observations of a TNF transportation engineer, as well as occurrences of road failures. We used the modeled potential environmental impact to negatively weight roads for a least-cost path network analysis to 1573 points of interest in the forest. The network analysis showed that out of 8233 km of road analyzed in the forest, 3483 km (42%) must be kept in a modified road network to ensure access to these points. We found that the modified network had improved patch characteristics, such as significantly fewer cherry stem roads intruding into patches, an improved area-weighted mean shape index, and larger mean patch sizes, as compared to the original network. This analysis system could be used by any public agency to analyze infrastructure for environmental or other risk and included in other mandated analyses such as risks to watersheds. 相似文献