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To flee or not to flee: predator avoidance by cheetahs at kills   总被引:2,自引:0,他引:2  
Mammalian carnivores are unusual because their primary competitors for food are often their primary predators. This relationship is most evident at persistent kills where dominant competitors are attracted to both the carcass (as a free meal) and to the killers (as potential prey). Cheetahs (Acinonyx jubatus) are frequent victims of kleptoparasitism, and cubs, and sometimes adults, are killed by lions (Panthera leo) or spotted hyenas (Crocuta crocuta). Between 1980 and 2002, we observed 639 kills made by cheetahs in Serengeti National Park, Tanzania. These kills were often visited by scavengers, including relatively innocuous species such as vultures and jackals and potentially dangerous species, like spotted hyenas and lions. We used cheetah behavior at kills to test a number of predictions about how cheetahs should minimize risk at kill sites given they face an increased risk of predation of themselves or their cubs. In particular, we examined the propensity of cheetahs of different age/sex classes to hide carcasses after making a kill, vigilance at kills, and the delay in leaving after finishing feeding with respect to ecological factors and scavenger presence. The behavior of single females at kills did not suggest that they were trying to avoid being killed, but the behavior of males, often found in groups, was in line with this hypothesis. In contrast, the behavior of mother cheetahs at kills appeared to be influenced greatly by the risk of cubs being killed. Our results suggest that cheetahs use several behavioral counterstrategies to avoid interspecific predation of self or cubs.  相似文献   
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Understanding the drivers of natural habitat conversion is a major challenge, yet predicting where future losses may occur is crucial to preventing them. Here, we used Bayesian analysis to model spatio-temporal patterns of land-use/cover change in two protected areas designations and unclassified land in Tanzania using time-series satellite images. We further investigated the costs and benefits of preserving fragmenting habitat joining the two ecosystems over the next two decades. We reveal that habitat conversion is driven by human population, existing land-use systems and the road network. We also reveal the probability of habitat conversion to be higher in the least protected area category. Preservation of habitat linking the two ecosystems saving 1640 ha of land from conversion could store between 21,320 and 49,200 t of carbon in the next 20 years, with the potential for generating between US$ 85,280 and 131,200 assuming a REDD+ project is implemented.  相似文献   
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We considered a series of conservation-related research projects on the island of Pemba, Tanzania, to reflect on the broad significance of Beier et al.’s recommendations for linking conservation science with practical conservation outcomes. The implementation of just some of their suggestions can advance a successful coproduction of actionable science by small research teams. Key elements include, first, scientists and managers working together in the field to ensure feedback in real time; second, questions jointly identified by managers and researchers to facilitate engaged collaboration; third, conducting research at multiple sites, thereby broadening managers’ abilities to reach multiple stakeholders; and fourth, establishing a multidisciplinary team because most of the concerns of local managers require input from multiple disciplines.  相似文献   
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In this study the total activity of 137Cs deposited per unit area over the Spanish peninsular territory was analysed using a 150 × 150 km2 mesh grid, with samples taken from 29 points. The deposited activities ranged between 251 and 6074 Bq/m2. A linear relationship was obtained between these values and the mean annual rainfall at each sampling point which allowed a map to be drawn, using GIS software, which shows the distribution of total deposited 137Cs activity across the Spanish mainland. At twelve of these sampling points the vertical migration profile of 137Cs was obtained. These profiles are separated into two groups with different behaviour, one of which includes clay and loam soils and the other containing sandy soils. For both groups of profiles the parameters of the convective-diffusive model, which describes the vertical migration of 137Cs in the soil, v (apparent convection velocity) and D (apparent diffusion coefficient) were calculated.  相似文献   
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Focal Species   总被引:2,自引:0,他引:2  
Tim Caro 《Conservation biology》2000,14(6):1569-1570
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Tanzania, arguably mainland Africa's most important nation for conservation, is losing habitat and natural resources rapidly. Moving away from a charcoal energy base and developing sustainable finance mechanisms for natural forests are critical to slowing persistent deforestation. Addressing governance and capacity deficits, including law enforcement, technical skills, and funding, across parts of the wildlife sector are key to effective wildlife protection. These changes could occur in tandem with bringing new models of natural resource management into play that include capacity building, corporate payment for ecosystem services, empowering nongovernmental organizations in law enforcement, greater private‐sector involvement, and novel community conservation strategies. The future of Tanzania's wildlife looks uncertain—as epitomized by the current elephant crisis—unless the country confronts issues of governance, embraces innovation, and fosters greater collaboration with the international community.  相似文献   
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Summary Free-living cheetah (Acinonyx jubatus) cubs are killed by a number of predators, thus vigilance in cheetah mothers may be a form of anti-predator behaviour as well as a means of locating prey. Mothers' vigilance during the day was closely associated with measures of hunting but not with measures of anti-predator behaviour. In contrast, mothers' vigilance at kills was not related to hunting but was related to anti-predator behaviour. Both forms of vigilance decreased as cubs grew older. Vigilance during the day increased with litter size which supports a model of shared parental investment (Lazarus and Inglis 1986) because after prey had been located and caught by mothers, cubs shared the prey between them. Vigilance at kills did not increase with litter size when cubs were young; in these situations predators stole cheetahs' prey and rarely chased cubs so, at most, only a single cub would be taken. Mothers' anti-predator behaviour away from kills did increase with litter size at young cub ages however; more cubs are killed in these circumstances the greater is the size of the litter. When cubs were older and could outrun predators, neither vigilance at kills nor anti-predator behaviour increased with litter size. These results strongly support two models of unshared investment (Lazarus and Inglis 1986) and demonstrate, not only that superficially similar behaviour has different functions in different contexts, but that parental investment is shaped by the type of benefits accrued from it.  相似文献   
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