Data from: Does habitat specialization shape the evolutionary potential of wild bird populations?

Because specialist species evolved in more temporally and spatially homogeneous environments than generalist species, they are supposed to experience less fluctuating selection. For this reason, we expect specialists to show lower overall genetic variation as compared to generalists. We also expect populations from specialist species to be smaller and more fragmented, with lower neutral genetic diversity. We tested these hypotheses by investigating patterns of genetic diversity along a habitat specialization gradient in wild birds, based on estimates of heritability, coefficients of variation of additive genetic variance, and heterozygosity available in the literature. We found no significant effect of habitat specialization on any of the quantitative genetic estimators but generalists had higher heterozygosity. This effect was mainly a consequence of the larger population size of generalists. Our results suggest that evolutionary potential does not differ at the population level between generalist and specialist species, but the trend observed in heterozygosity levels and population sizes may explain their difference in susceptibility to extinction.

相较于广适性物种，特化物种演化所处的时空环境更为均质，因此其经历的选择波动理应更弱。据此，我们预期特化物种的整体遗传变异水平低于广适性物种。我们同时推测，特化物种种群的规模更小、片段化程度更高，且中性遗传多样性更低。本研究基于文献中已报道的遗传力（heritability）、加性遗传方差（additive genetic variance）变异系数以及杂合性（heterozygosity）估算值，通过探究野生鸟类沿生境特化（habitat specialization）梯度的遗传多样性模式，对上述假说进行了检验。研究发现，生境特化程度对所有数量遗传估算指标均无显著影响，但广适性物种的杂合性水平更高。该效应主要源于广适性物种拥有更大的种群规模。本研究结果表明，广适性与特化物种在种群水平上的演化潜力并无差异，但杂合性水平与种群规模所呈现的差异趋势，或可解释二者在灭绝易感性上的不同。