Museum of Zoology and Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan.
Department of Environmental Science, Policy, & Management, University of California, Berkeley, Berkeley, California.
Mol Ecol. 2019 Apr;28(7):1664-1674. doi: 10.1111/mec.15042. Epub 2019 Apr 13.
Species abundance data are critical for testing ecological theory, but obtaining accurate empirical estimates for many taxa is challenging. Proxies for species abundance can help researchers circumvent time and cost constraints that are prohibitive for long-term sampling. Under simple demographic models, genetic diversity is expected to correlate with census size, such that genome-wide heterozygosity may provide a surrogate measure of species abundance. We tested whether nucleotide diversity is correlated with long-term estimates of abundance, occupancy and degree of ecological specialization in a diverse lizard community from arid Australia. Using targeted sequence capture, we obtained estimates of genomic diversity from 30 species of lizards, recovering an average of 5,066 loci covering 3.6 Mb of DNA sequence per individual. We compared measures of individual heterozygosity to a metric of habitat specialization to investigate whether ecological preference exerts a measurable effect on genetic diversity. We find that heterozygosity is significantly correlated with species abundance and occupancy, but not habitat specialization. Demonstrating the power of genomic sampling, the correlation between heterozygosity and abundance/occupancy emerged from considering just one or two individuals per species. However, genetic diversity does no better at predicting abundance than a single day of traditional sampling in this community. We conclude that genetic diversity is a useful proxy for regional-scale species abundance and occupancy, but a large amount of unexplained variation in heterozygosity suggests additional constraints or a failure of ecological sampling to adequately capture variation in true population size.
物种丰富度数据对于检验生态学理论至关重要，但对于许多分类群，准确获取经验数据具有挑战性。物种丰富度的替代指标可以帮助研究人员克服长期采样所面临的时间和成本限制。在简单的人口模型下，遗传多样性预计与种群大小相关，因此全基因组杂合性可能提供物种丰富度的替代测量指标。我们在来自澳大利亚干旱地区的一个多样化蜥蜴群落中，测试了核苷酸多样性是否与长期的丰度、占有度和生态专业化程度估计值相关。通过靶向序列捕获，我们从 30 种蜥蜴中获得了基因组多样性的估计值，平均每个个体获得了 5066 个覆盖 3.6 Mb 的 DNA 序列的基因座。我们将个体杂合性的度量与栖息地专业化的度量进行比较，以研究生态偏好是否对遗传多样性产生可测量的影响。我们发现，杂合性与物种丰富度和占有度显著相关，但与栖息地专业化无关。基因组采样的威力得到了证明，仅考虑每个物种的一两个个体，杂合性与丰度/占有度之间的相关性就显现出来了。然而，在这个群落中，遗传多样性在预测丰度方面并不比传统采样一天的效果好。我们得出结论，遗传多样性是区域尺度物种丰富度和占有度的有用替代指标，但杂合性存在大量无法解释的变异，表明存在其他限制因素或生态采样未能充分捕捉真实种群大小的变异。
