Data from: Mapping extinction debt highlights conservation opportunities for birds and mammals in the South American Chaco

1. Habitat loss is the primary cause of local extinctions. Yet, there is considerable uncertainty regarding how fast species respond to habitat loss, and how time-delayed responses vary in space. 2. We focused on the Argentine Dry Chaco (ca. 32 million ha), a global deforestation hotspot, and tested for time-delayed response of bird and mammal communities to landscape transformation. We quantified the magnitude of extinction debt by modelling contemporary species richness as a function of either contemporary or past (2000 and 1985) landscape patterns. We then used these models to map communities’ extinction debt. 3. We found strong evidence for an extinction debt: landscape structure from 2000 explained contemporary species richness of birds and mammals better than contemporary and 1985 landscapes. This suggests time-delayed responses between 10 and 25 years. Extinction debt was especially strong for forest specialists. 4. Projecting our models across the Chaco highlighted areas where future local extinctions due to unpaid extinction debt are likely. Areas recently converted to agriculture had highest extinction debt, regardless of the post-conversion land use. Few local extinctions were predicted in areas with remaining larger forest patches. 5. Synthesis and applications. The evidence for an unpaid extinction debt in the Argentine Dry Chaco provides a substantial window of opportunity for averting local biodiversity losses. However this window may close rapidly if conservation activities such as habitat restoration are not implemented swiftly. Our extinction debt maps highlights areas where such conservation activities should be implemented.1. 栖息地丧失是引发本地物种灭绝的首要诱因。然而，关于物种响应栖息地丧失的速率，以及时滞响应在空间上的变异规律，目前仍存在相当大的不确定性。2. 本研究聚焦于阿根廷干燥查科（Argentine Dry Chaco，约3200万公顷）这一全球森林砍伐热点区域，探究鸟类与哺乳动物群落对景观转化的时滞响应。我们以当代物种丰富度为因变量，分别以当代、2000年及1985年的景观格局为自变量构建模型，以此量化灭绝债（extinction debt）的规模。随后利用这些模型绘制了各群落的灭绝债空间分布图。3. 研究结果为灭绝债的存在提供了强有力的证据：2000年的景观结构对鸟类和哺乳动物当代物种丰富度的解释力，优于当代及1985年的景观格局。这表明物种响应存在10至25年的时滞。其中，森林特化物种的灭绝债效应尤为显著。4. 将模型外推至整个查科区域后，我们识别出了因未清偿灭绝债而大概率发生未来本地灭绝的区域。近期被转化为农业用地的区域灭绝债水平最高，且不受转化后的土地利用类型影响。而在仍保留大面积森林斑块的区域，预测的本地灭绝事件极少。5. 综合与应用。阿根廷干燥查科区域存在未清偿灭绝债的研究结论，为规避本地生物多样性丧失提供了宝贵的时间窗口。但若未能快速开展栖息地修复等保护行动，该窗口或将快速关闭。本研究绘制的灭绝债空间分布图，明确了此类保护行动的优先实施区域。