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Ecologically enhanced areas - a key habitat structure for re-introduced grey partridges Perdix perdix [An article from: Biological Conservation]
This digital document is a journal article from Biological Conservation, published by Elsevier in . The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser. Description: We analysed the spatial distribution of home-ranges and the habitat use of re-introduced grey partridges Perdix perdix in relation to newly established ecologically enhanced areas, i.e. wild-flower strips and hedges, within an intensively cultivated area in Switzerland from which the species had become extinct. All birds settled within the ca. 30% of the study area where the proportion of enhanced areas was highest (5.8%). At the level of the individual family group, we found a significant over-proportional use of enhanced areas throughout the year. Furthermore, when the birds used the agricultural fields, the use densities strongly declined with distance from the nearest enhanced area. Thus, the availability and spatial distribution of ecologically enhanced areas were the main determinants of the partridges' range use. These results indicate that a framework of ecologically enhanced areas is a key habitat structure for grey partridges, and that these enhancements, even if small in proportion, were the crucial first measure to restore the research area to an appropriate grey partridge habitat and, thus, the basis for successful re-introduction in this intensively cultivated area. .
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Re-establishing vegetation on bare patches in the Nama Karoo, South Africa [An article from: Journal of Arid Environments]
This digital document is a journal article from Journal of Arid Environments, published by Elsevier in 2004. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser. Description: Bare patches are found throughout the Nama Karoo. The development of bare patches is a degradation process that can be attributed to poor grazing practices such as overgrazing and patch selection, usually in combination with drought conditions. The restoration of vegetation in such degraded rangeland is seldom achieved through the withdrawal of livestock alone. Some form of intervention is usually necessary to promote a favourable environment for the establishment of plants. In this study various methods of re-establishing vegetation in bare patches were identified and tested, either alone or in combination. The treatments were: seeded, seeded+branches, tilled, tilled+seeded, tilled+seeded+branches and a control. The tilled+seeded+branches treatment was the most successful in providing a suitable environment for the establishment of desirable plant species, but the tilled treatment the most cost-effective. .
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Comparison of survival rates of captive-reared and wild-bred Mauritius kestrels (Falco punctatus) in a re-introduced population [An article from: Biological Conservation]
This digital document is a journal article from Biological Conservation, published by Elsevier in 2004. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser. Description: Re-introduction is a technique widely used in the conservation of threatened bird species. With advances in aviculture the use of captive-produced individuals as the release stock is becoming more commonplace, and ideally, survival of captive-produced, released individuals should be no different from their wild-bred counterparts. During the late 1980s the Critically Endangered Mauritius kestrel (Falco punctatus) was successfully re-introduced into the Bambous mountain range, Mauritius, some 30 years after its local extinction. Between 1987 and 2001 the developing population was closely monitored enabling us to construct re-sighting histories for 88 released and 284 wild-bred kestrels. We used age-structured models in the survival analysis software program MARK to determine if an individual's origin influenced its subsequent survival. Our analysis indicated no compelling evidence for reduced survival among juvenile captive-reared and released individuals, relative to their wild-bred counterparts, across the majority of cohorts and only limited evidence of a cohort-specific effect. This study illustrates that despite the lack of a formal experimental approach it is still feasible to conduct an assessment of re-introduction outcomes and techniques. .
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