Data from: Rapid phenotypic change in a native bird population following conversion of the Colorado Desert to agriculture

Humans are modifying our planet’s ecosystems with increasing frequency and intensity. Exploring population responses to anthropogenic modifications of natural habitat provides insights into how species persist in the Anthropocene. Here, we leverage natural history collections to document rapid phenotypic change within a native bird population following 80 years of agriculture in the Colorado Desert of southeastern California. By comparing spectrophotometric measurements of Horned Lark (Eremophila alpestris) specimens collected in the Imperial Valley from 1918 to 1934 to those collected from 1984 to 2014, we found that more recent birds have darker backs, napes, and crowns. This dorsal darkening may have resulted from a shift in selective pressures for camouflage induced by land use: previously, the lark population nested on light-colored desert flats, whereas contemporary larks occupy darker soil associated with agricultural fields. Adaptation and/or introgression may have contributed to this instance of rapid phenotypic change following the rise of agriculture in the Imperial Valley.

人类正以愈发频繁且剧烈的强度改变地球的生态系统。探究种群对自然栖息地人为改造的响应，可为理解物种在人类世（Anthropocene）中的存续路径提供重要洞见。本研究依托自然历史馆藏，记录了加利福尼亚东南部科罗拉多荒漠地区一处本土鸟类种群在经历80年农业开发后的快速表型变化。通过对比1918年至1934年与1984年至2014年在帝国谷采集的角百灵（Horned Lark，Eremophila alpestris）标本的分光光度测量数据，我们发现近期的种群个体背部、颈背及头顶颜色更深。这种背部体色加深的现象，可能源于土地利用变化引发的伪装选择压力偏移：此前该角百灵种群营巢于浅色荒漠滩涂，而如今的种群则栖息在与农田相关的深色土壤区域。适应或基因渐渗（introgression）或为帝国谷农业兴起后此次快速表型变化的促成因素。