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We propose and test a method to determine the proportion of specific animal national populations included in a network of
protected areas. The proposed method further allows identifying the best potential new sites to be included in the network,
to reach target population sizes and so to test whether a network extension is realistic or not. We used data from the French
Breeding Bird Survey (BBS) and spatial interpolation models known as kriging to predict the relative abundance of species
at a national scale. We applied the proposed methodology to Special Protection Areas (SPAs) and a sample of 20 bird species
concerned by the Directive of the Council of the European Community on the Conservation of Wild Birds. We estimated which
relative part of the national population is included within the boundaries of all national SPAs. Our results suggest that
the current SPA network is probably not efficient to ensure favorable national conservation status for the most widespread
species, but allows reaching a 5% target value for more localized ones. Consequently, we discuss the limit of such a protected
area network to ensure the global conservation of widespread species, and therefore the need for other large-scale conservation
measures. 相似文献
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Moritz Mercker Nele Markones Kai Borkenhagen Henriette Schwemmer Johannes Wahl Stefan Garthe 《The Journal of wildlife management》2021,85(4):751-771
Generating trend and population estimates from bird count data is challenging and a variety of factors have to be taken into account. We present an integrative statistical approach for estimating population numbers and trends for seabirds at sea. The method allows for the integration of bird-count data from different sources and sampling schemes: offshore observer-based line transect and digital strip transect surveys and land-based point counts; the estimation of log-linear and highly nonlinear trends; the prediction of population numbers for predefined sub-areas, years, or seasons; and investigations of the effects of various environmental and detection-related covariates on bird count numbers. We applied the approach to count data for great black-backed gulls (Larus marinus) in the German part of the North Sea and Baltic Sea from 1990–2016. Count data were collected by observer-based offshore ship and aerial surveys, offshore digital aerial surveys, and point counts from the shore. The detectability of great black-backed gulls was affected by the sea state (the condition of the sea surface, characterized by wave height, wave form, foam, and spray) and survey method. Digital and observer-based aerial surveys detected only 59–77% of the abundance recorded by ship-based surveys. Great black-backed gulls are mainly present in German waters in winter, when they account for 3–4% of the European population. Their core distributional areas are mainly in deeper offshore waters where they are relatively dispersed, with several concentrations probably connected to fishing activity. Great black-backed gulls have undergone substantial declines, with the most pronounced decreases of >90% in the offshore waters of the German part of the North Sea. Breeding numbers at important European breeding sites do not show similar declines, suggesting that the trends observed in the sea areas might indicate a shift in the distribution or habitat use and a decreasing importance of marine areas for European great black-backed gulls. © 2021 The Authors. The Journal of Wildlife Management published by Wiley Periodicals LLC on behalf of The Wildlife Society. 相似文献
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M. G. BETTS D. MITCHELL A. W. DIAMOND J. BÉTY 《The Journal of wildlife management》2007,71(7):2266-2273
ABSTRACT Roadside survey data have been used frequently to assess species occurrence and population trends and to establish conservation priorities. However, most studies using such data assume that samples are representative of either the amount of habitat or its rate of change at larger spatial scales. We tested both of these assumptions for the Breeding Bird Survey (BBS) from 1974 to 2001 in New Brunswick, Canada. Our study focused on mature forest—a cover type that we predicted would be characterized by rapid change due to human activities and that is of high ecological importance. We also sought to determine whether land cover changes adjacent to BBS routes were related to bird population trends detected in BBS data. Within all 3 time periods examined (1970s, 1980s, and 1990s), the amount of mature forest adjacent to BBS routes was significantly lower than in surrounding 1° blocks of latitude and longitude. This could be problematic for studies that use roadside data to compare the relative abundance of species. On average, mature forest declined at a rate of-1.5% per year over the 28-year study period. We detected no significant difference in the rate of change between degree blocks and BBS routes over this time span. However, in the 1970s and 1980s, mature forest declined more rapidly in degree blocks (-2.7%/yr) than adjacent to BBS routes (-0.5/yr). We also found that the BBS trend for a mature forest-associated species, blackburnian warbler (Dendroica fusca), was correlated with the trend in mature forest along BBS routes. This, combined with slower rates of mature forest change along routes in the 1970s and 1980s, suggests that BBS data may have underestimated population declines during this period. It is important that research be conducted to test for potential biases in roadside surveys caused by uneven rates of landscape change, particularly in regions characterized by rapid habitat alteration. 相似文献