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Abstract: Marine protected areas (MPAs), including no‐take marine reserves (MRs), play an important role in the conservation of marine biodiversity. We document the status of MPAs and MRs in Latin America and the Caribbean, where little has been reported on the scope of such protection. Our survey of protected area databases, published and unpublished literature, and Internet searches yielded information from 30 countries and 12 overseas territories. At present more than 700 MPAs have been established, covering more than 300,000 km2 or 1.5% of the coastal and shelf waters. We report on the status of 3 categories of protection: MPAs (limited take throughout the area), MRs (no‐take throughout the area), and mixed‐use (a limited‐take MPA that contains an MR). The majority of protected areas in Latin America and the Caribbean are MPAs, which allow some or extensive extractive activities throughout the designated area. These 571 sites cover 51,505 km2 or 0.3% of coastal and shelf waters. There are 98 MRs covering 16,862 km2 or 0.1% of the coastal and shelf waters. Mixed‐use MPAs are the fewest in number (87), but cover the largest area (236,853 km2, 1.2%). Across Latin America and the Caribbean, many biogeographic provinces are underrepresented in these protected areas. Large coastal regions remain unprotected, in particular, the southern Pacific and southern Atlantic coasts of South America. Our analysis reveals multiple opportunities to strengthen marine conservation in Latin America and the Caribbean by improving implementation, management, and enforcement of existing MPAs; adding new MPAs and MRs strategically to enhance connectivity and sustainability of existing protection; and establishing new networks of MPAs and MRs or combinations thereof to enhance protection where little currently exists.  相似文献   
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Anthropogenic climate change is a key threat to global biodiversity. To inform strategic actions aimed at conserving biodiversity as climate changes, conservation planners need early warning of the risks faced by different species. The IUCN Red List criteria for threatened species are widely acknowledged as useful risk assessment tools for informing conservation under constraints imposed by limited data. However, doubts have been expressed about the ability of the criteria to detect risks imposed by potentially slow‐acting threats such as climate change, particularly because criteria addressing rates of population decline are assessed over time scales as short as 10 years. We used spatially explicit stochastic population models and dynamic species distribution models projected to future climates to determine how long before extinction a species would become eligible for listing as threatened based on the IUCN Red List criteria. We focused on a short‐lived frog species (Assa darlingtoni) chosen specifically to represent potential weaknesses in the criteria to allow detailed consideration of the analytical issues and to develop an approach for wider application. The criteria were more sensitive to climate change than previously anticipated; lead times between initial listing in a threatened category and predicted extinction varied from 40 to 80 years, depending on data availability. We attributed this sensitivity primarily to the ensemble properties of the criteria that assess contrasting symptoms of extinction risk. Nevertheless, we recommend the robustness of the criteria warrants further investigation across species with contrasting life histories and patterns of decline. The adequacy of these lead times for early warning depends on practicalities of environmental policy and management, bureaucratic or political inertia, and the anticipated species response times to management actions. Detección del Riesgo de Extinción a partir del Cambio Climático por medio del Criterio de la Lista Roja de la UICNKeith et al.  相似文献   
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Abstract:  Long-term research projects can provide important conservation benefits, not only through research specifically focused on conservation problems, but also from various incidental benefits, such as increased intensity of monitoring and building support for the protection of an area. At Gombe National Park, Tanzania, long-term research has provided at least four distinct benefits to wildlife conservation. (1) Jane Goodall's groundbreaking discoveries of chimpanzee (Pan troglodytes) tool use, hunting, and complex social relationships in what was then a game reserve drew attention to the area and created support for upgrading Gombe to national park status in 1968. (2) The highly publicized findings have earned Gombe and Tanzania the attention of a worldwide public that includes tourists and donors that provide financial support for Gombe, other parks in Tanzania, and chimpanzee conservation in general. (3) Crucial information on social structure and habitat use has been gathered that is essential for effective conservation of chimpanzees at Gombe and elsewhere. (4) A clear picture of Gombe's chimpanzee population over the past 40 years has been determined, and this has helped identify the greatest threats to the viability of this population, namely disease and habitat loss outside the park. These threats are severe and because of the small size of the population it is extremely vulnerable. Research at Gombe has led to the establishment of conservation education and development projects around Gombe, which are needed to build local support for the park and its chimpanzees, but saving these famous chimpanzees will take a larger integrated effort on the part of park managers, researchers, and the local community with financial help from international donors.  相似文献   
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Abstract:  Ranches are being converted to exurban housing developments in the southwestern United States, with potentially significant but little-studied impacts on biological diversity. We captured rodents on 48 traplines in grasslands, mesquite savannas, and oak savannas in southeastern Arizona that were grazed by livestock, embedded in exurban housing developments, grazed and embedded in development, or neither grazed nor embedded in development. Independent of habitat or development, rodent species richness, mean rank abundance, and capture rates of all rodents combined were negatively related to presence of livestock grazing or to its effects on vegetative ground cover. Exurban development had no obvious effects on rodent variety or abundance. Results suggest southwestern exurban developments can sustain a rich assemblage of grassland and savanna rodents if housing densities are low and houses are embedded in a matrix of natural vegetation with little grazing.  相似文献   
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Ozone reduction enhances the amount of ultraviolet (UV) radiation reaching the aquatic ecosystems, which can induce adverse effects on fish. In order to study the UV radiation effects on skin structure and ultrastructure, the alevins of Salmo trutta caspius were exposed to two different doses of UV radiation (low doses of: 60 µW cm?2 UVC; 100 µW cm?2 UVB; and 40 µW cm?2 UVA and high doses of: 90 µW cm?2 UVC; 130 µW cm?2 UVB; and 50 µW cm?2 UVA) for 15 min once a day in dark condition. Alevins with no exposure to either solar light or UV exposure served as the control group. No mortality was observed in the control group, whereas all of the alevins died in the 9th day in both UV exposure groups. Light microscopic and scanning electron microscopic studies showed significant reduction in the epidermis thickness, number of skin mucous cells, and percentage of mucus secreting cells in both UV exposure groups. Sunburn cells, lifting epidermis from basal membrane, and disappearance of pavement cell microridges were also observed. Our results showed that UV radiation caused intensive skin cell lesions in the Caspian salmon alevins. Since the skin cells of trout alevins possesses essential roles in respiration, osmoregulation, excretion and defense, the observed damages to the skin could be attributed to their sudden mortality in the UV exposure.  相似文献   
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Pollution due to persistent pesticides is not a regional but a global problem. Organochlorine pesticides are persistent chemicals, stored and accumulated in the tissues of a wide variety of invertebrates and vertebrates including marine species. In the present study the organochlorine residues HCHs, DDTs and PCBs were measured in different trophic groups of birds (scavengers, inland piscivores, coastal piscivores, insectivores, granivores and omnivores) collected from Tamil Nadu Coast, India. The residue accumulation as a function of sex did not depict distinct variation. However, females had lower residue levels than males in terms of their mean weight and feeding habits. A continuous monitoring programme is recommended to establish the studied organisms as indicator species.  相似文献   
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Nickel pollution is a serious environmental problem, and its effects may provoke alterations in the ecosystem and in organism of animals and humans. Dermatitis, eczema, and asthma are some illnesses caused by Ni2+ poisoning. In this work, fish fed either Ni2+-enriched pellets or commercial pellets were studied. The amount of Ni2+ in fish were measurements by adsorptive stripping voltammetry (AdSV) with dimethylglyoxime as a complexing agent. The analysis of Ni2+ in fish by AdSV established that its accumulation occurs principally in viscera (670.86 ± 5.82 µg g?1), in the head (697.12 ± 2.77 µg g?1) and in the muscle (405.82 ± 3.26 µg g?1), both after 12 months of experiments. Ni2+ adsorbs preferentially in organs such as the stomach, the intestine, and the kidneys and acts in the central nervous system as well. Tilapia growth and mass were significantly affected by Ni2+ poisoning. From statistical analysis, observed that the results for lengths, weights and metal concentration were different for each sampling at significance level of p < 0.05. The Ni2+ concentration in tilapia was enough to cause the death of tilapias; however, it did not occur because the presence of Zn2+ might act as protective agent of heavy metals.  相似文献   
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Abstract: Fragmentation of natural habitats can increase numbers of rare species. Conservation of rare species requires experts and resources, which may be lacking for many species. In the absence of regular surveys and expert knowledge, historical sighting records can provide data on the distribution of a species. Numerous models have been developed recently to make inferences regarding the threat status of a taxon on the basis of variation in trends of sightings over time. We applied 5 such models to national and regional (county) data on 3 red‐listed orchid species (Cephalanthera longifolia, Hammarbya paludosa, and Pseudorchis albida) and 1 species that has recently come to the attention of conservation authorities (Neotinea maculata) in the Republic of Ireland. In addition, we used an optimal linear estimate to calculate the time of extinction for each species overall and within each county. To account for bias in recording effort over time, we used rarefaction analysis. On the basis of sighting records, we inferred that these species are not threatened with extinction and, although there have been declines, there is no clear geographical pattern of decline in any species. Most counties where these orchid species occurred had a low number of sightings; hence, we were cautious in our interpretation of output from statistical models. We suggest the main drivers of decline in these species in Ireland are modification of habitats for increased agricultural production and lack of appropriate management. Our results show that the application of probabilistic models can be used even when sighting data are scarce, provided multiple models are used simultaneously and rarefaction is used to account for bias in recording effort among species over time. These models could be used frequently when making an initial conservation assessment of species in a region, particularly if there is a relatively constant recording rate and some knowledge of the underlying recording process. Regional‐scale analyses, such as ours, complement World Conservation Union criteria for assessment of the extinct category and are useful for highlighting areas of under recording and focusing conservation efforts of rare and endangered species.  相似文献   
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