Declines in rodent abundance and diversity track regional climate variability in North American drylands
Declines in rodent abundance and diversity track regional climate variability in North American drylands
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DOI：
10.1111/gcb.15672
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发表时间：
2021-06-10
影响因子：
11.6
通讯作者：
Rudgers, Jennifer A.
中科院分区：
文献类型：
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作者：
Cardenas, Pablo A.;Christensen, Erica;Rudgers, Jennifer A.
区域长期监测可以加强对与气候变化有关的生物多样性下降的检测，通过减少对空间换时间的依赖和提高可扩展性来改进未来预测。啮齿动物是旱地的多样化和重要消费者，旱地的定义是水资源稀缺，该地区覆盖了地球陆地表面的45%，面临着越来越干燥和更加多变的气候。我们分析了美国西南部草原、灌丛、交错带和林地生态系统中22种啮齿动物的丰度数据。两个时间序列(1995-2006年和2004-2013年)与影响北美西南部干旱的太平洋年代际涛动(PDO)的阶段重合。在区域范围内，啮齿动物物种多样性下降了20%-35%，后期损失更大。丰度也在地区范围内下降，但仅在2004-2013年间，捕获的动物数量减少了5%。在第一个时间序列中(较潮湿的气候)，植物生产力超过气候变量，成为预测70%的分类群啮齿动物丰度的最佳区域因子，而在第二个时间序列中(较干燥的气候)，气候最好地解释了60%的分类群的丰度变化。不同生态系统多样性和丰富度的时间动态在空间上有所不同，新墨西哥州中部和科罗拉多州中部的林地和灌木丛的降幅最大。在干旱加剧和干旱年际变化放大的情况下，哪些物种是赢家或输家取决于生态系统类型和PDO的阶段。在干旱下，显著赢家(18%)的类群比失败者(30%)少，但70%的类群的赢家和输家的身份在不同的生态系统中是不同的。我们的结果表明，啮齿动物物种对气候的敏感性导致了1995-2013年间区域多样性和丰度的下降。这些变化是否预示着美国西南部对干旱敏感的消费者未来的下降将取决于下一个主要PDO周期的气候。
Regional long-term monitoring can enhance the detection of biodiversity declines associated with climate change, improving future projections by reducing reliance on space-for-time substitution and increasing scalability. Rodents are diverse and important consumers in drylands, regions defined by the scarcity of water that cover 45% of Earth's land surface and face increasingly drier and more variable climates. We analyzed abundance data for 22 rodent species across grassland, shrubland, ecotone, and woodland ecosystems in the southwestern USA. Two time series (1995-2006 and 2004-2013) coincided with phases of the Pacific Decadal Oscillation (PDO), which influences drought in southwestern North America. Regionally, rodent species diversity declined 20%-35%, with greater losses during the later time period. Abundance also declined regionally, but only during 2004-2013, with losses of 5% of animals captured. During the first time series (wetter climate), plant productivity outranked climate variables as the best regional predictor of rodent abundance for 70% of taxa, whereas during the second period (drier climate), climate best explained variation in abundance for 60% of taxa. Temporal dynamics in diversity and abundance differed spatially among ecosystems, with the largest declines in woodlands and shrublands of central New Mexico and Colorado. Which species were winners or losers under increasing drought and amplified interannual variability in drought depended on ecosystem type and the phase of the PDO. Fewer taxa were significant winners (18%) than losers (30%) under drought, but the identities of winners and losers differed among ecosystems for 70% of taxa. Our results suggest that the sensitivities of rodent species to climate contributed to regional declines in diversity and abundance during 1995-2013. Whether these changes portend future declines in drought-sensitive consumers in the southwestern USA will depend on the climate during the next major PDO cycle.