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驱动因素。然而，学界对于物种响应栖息地丧失的速率，以及时滞响应的空间差异，仍存在大量不确定性。 2. 本研究聚焦于面积约3200万公顷的阿根廷大查科干旱区（Argentine Dry Chaco）——这一区域为全球森林砍伐热点——以检验鸟类与哺乳类群落对景观转变的时滞响应。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，以此量化灭绝债务（extinction debt）的规模；随后借助这些模型绘制了各群落的灭绝债务空间分布图。 3. 研究结果为灭绝债务提供了坚实的实证支撑：2000年的景观结构对鸟类和哺乳类当代物种丰富度的解释效果，优于当代及1985年的景观格局，这表明时滞响应的时间跨度介于10至25年之间。其中，森林特化物种的灭绝债务表现尤为显著。 4. 基于研究模型对大查科地区进行全域预测后发现，部分区域极有可能因未清偿的灭绝债务发生未来的本地物种灭绝事件。近期被转化为农业用地的区域灭绝债务水平最高，且不受后续土地利用方式的影响。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发生。 5. 总结与应用：阿根廷大查科干旱区存在未清偿灭绝债务的实证证据，为规避本地生物多样性丧失提供了宝贵的时间窗口。但若未能快速推进栖息地修复等保护举措，该时间窗口或将快速关闭。本研究绘制的灭绝债务空间分布图，可为相关保护行动的精准实施提供明确的区位指引。