Genetic and paleomodelling evidence of the population expansion of the cattle egret Bubulcus ibis in Africa during the climatic oscillations of the Late Pleistocene

Increasing aridity during glacial periods produced the retraction of forests and the expansion of arid and semi-arid environments in Africa, with consequences for birds. Cattle egret (Bubulcus ibis) is a dispersive species that prefers semiarid environments and requires proximity to bodies of water. We expected that climatic oscillations led to the expansion of the range of the cattle egret during arid periods, such as the Last Maximum Glacial (LGM) and contraction of distribution during the Last Interglacial (LIG) period, resulting in contact of populations previously isolated. We investigated this hypothesis by evaluating the genetic structure and population history of 15 cattle egret breeding colonies located in West and South Africa using the mitochondrial DNA (mtDNA) control region, mtDNA ATPase 8 and 6, and an intron of nuclear gene transforming growth factor beta-2. Occurrence data and bioclimatic information were used to generate ecological niche models of three periods (present...

冰川期内干旱程度加剧，导致非洲地区森林退缩、干旱与半干旱环境扩张，这对当地鸟类产生了影响。牛背鹭（Bubulcus ibis）是一种具有扩散能力的物种，偏好半干旱环境且需要邻近水体。我们推测，气候波动会使牛背鹭在末次盛冰期（LGM）等干旱时期的分布范围扩张，而在末次间冰期（LIG）时期分布范围收缩，进而导致此前隔离的种群产生接触。本研究以分布于西非与南非的15个牛背鹭繁殖种群为研究对象，通过线粒体DNA（mtDNA）控制区、mtDNA ATPase 8和6基因以及核基因转化生长因子β-2的内含子序列，对其遗传结构与种群历史展开分析，以验证上述假说。研究还利用出现记录数据与生物气候信息，构建了三个时期（现今……）的生态位模型。