Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK.
Social and Public Health Sciences Unit, University of Glasgow, Glasgow, UK.
Nat Ecol Evol. 2022 Mar;6(3):324-331. doi: 10.1038/s41559-021-01653-3. Epub 2022 Feb 10.
Species extinctions and colonizations in response to land cover change often occur with time lags rather than instantaneously, leading to extinction debts and colonization credits. These debts and credits can lead to erroneous predictions of future biodiversity. Recent attempts to measure debts and credits have been limited to small geographical areas and have not considered multiple land cover types, or the directionality of land cover change. Here we quantify the relative contribution of past and current landscapes on the current effective number of species of 2,880 US bird communities, explicitly measuring the response of biodiversity to increases and decreases in five land cover types. We find that the current effective number of species is still largely explained by the past landscape composition (legacy effect), depending on the type, magnitude and directionality of recent land cover change. This legacy effect leads to widespread extinction debts and colonization credits. Specifically, we reveal debts across 52% of the United States, particularly in recently urbanized areas, and colonization credits in the remaining 48%, which are primarily associated with grassland decrease. We conclude that biodiversity policy targets risk becoming rapidly obsolete unless past landscapes are considered and debts and credits accounted for.
物种灭绝和迁移通常会随着时间的推移而发生，而不是即时发生，这导致了灭绝债务和殖民信用。这些债务和信用可能导致对未来生物多样性的错误预测。最近测量债务和信用的尝试仅限于小的地理区域，并且没有考虑多种土地覆盖类型，或者土地覆盖变化的方向性。在这里，我们量化了过去和当前景观对 2880 个美国鸟类群落当前有效物种数量的相对贡献，明确测量了生物多样性对五种土地覆盖类型增加和减少的反应。我们发现，当前有效物种数量在很大程度上仍然取决于过去的景观组成（遗留效应），具体取决于最近土地覆盖变化的类型、幅度和方向性。这种遗留效应导致了广泛的灭绝债务和殖民信用。具体来说，我们揭示了美国 52%的地区存在债务，特别是在最近城市化的地区，而在其余的 48%地区则存在殖民信用，这主要与草原减少有关。我们的结论是，除非考虑过去的景观并考虑债务和信用，否则生物多样性政策目标可能会迅速过时。
