Bird–habitat relationship for the declining Pampas meadowlark populations in the southern Pampas grasslands

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• 作者：Ferná ; ndez ; Gustavo J. ; Posse ; Gabriela ; Ferretti ; Valentina ; Gabelli ; Fabiá ; n M.
• 关键词：Pampas meadowlark ; Sturnella defilippii ; Pampas grasslands ; Population decline ; Habitat transformation
• 刊名：Biological Conservation
• 出版年：2004
• 出版时间：January, 2004
• 年：2004
• 卷：115
• 期：1
• 页码：139-148
• 全文大小：508 K

文摘

During the past century, the Pampas meadowlark Sturnella defilippii underwent a severe population drop and now, it is confined mostly to southern Pampas grasslands. We analyzed the habitat and landscape characteristics associated to the presence of reproductive groups of Pampas meadowlarks in this area. During the 1999 breeding season, we surveyed 89 randomly stratified selected points where we noted the presence/absence of Pampas meadowlarks. For each point we estimated seven habitat variables related to vegetation cover and six landscape variables derived from different maps. We found 11 groups of displaying males, nine of them on natural grassland plots. Multivariate analyses indicate that field type and vegetation cover are the main factors associated to the presence of Pampas meadowlark. Reproductive groups were found preferentially at natural grasslands with high vegetation cover. Habitat loss and intensive grazing of fields appear to be the main factors associated to their sharp population decline and distribution retraction.