Data from: Effects of fragmentation on plant adaptation to urban environments

Urban ecosystems are relatively recent and heavily human-altered
terrestrial ecosystems with a surprisingly high diversity of animals,
plants and other organisms. Urban habitats are also strongly fragmented
and subject to higher temperatures, providing a compelling model for
studying adaptation to global change. Crepis sancta (Asteraceae), an
annual Mediterranean wasteland weed, occupies fragmented urban
environments as well as certain unfragmented landscapes in southern
France. We tested for shifts in dispersal, reproductive traits and size
across a rural–urban gradient to learn whether and how selection may be
driving changes in life history in urban and fragmented habitats. We
specifically compared the structure of quantitative genetic variation and
of neutral markers (microsatellites) between urban and rural and between
fragmented and unfragmented habitats. We showed that fragmentation
provides a better descriptor of trait variation than urbanization per se
for dispersal traits. Fragmentation also affected reproductive traits and
plant size though one rural population did conform to this scheme. Our
study shows the role of fragmentation for dispersal traits shift in urban
environments and a more complex pattern for other traits. We discuss the
role of pollinator scarcity and an inhospitable matrix as drivers of
adaptation.

城市生态系统是一类相对新兴、受人类活动强烈改造的陆地生态系统，其动植物及其他生物类群的多样性却颇为惊人。城市生境同时具有强烈的破碎化特征，且环境温度更高，为探究全球变化下的生物适应性提供了极具说服力的研究模型。圣还阳参（Crepis sancta，菊科Asteraceae）是一年生地中海荒野草种，其分布既涵盖破碎化的城市生境，也包括法国南部部分未受破碎化的自然景观。本研究沿城乡梯度设置实验，检测该物种在扩散性状、繁殖性状及植株体型上的变异，以明确选择压力是否以及如何驱动城市与破碎化生境中生物生活史的改变。我们专门比较了城乡生境之间、破碎化与未破碎化生境之间的数量遗传变异结构与中性标记（微卫星microsatellites）的差异。研究结果表明，相较于城市化本身，生境破碎化更能解释扩散性状的变异模式。生境破碎化同时对繁殖性状与植株体型产生影响，但有一个乡村种群不符合这一规律。本研究证实了生境破碎化在城市环境中驱动扩散性状演变的作用，同时揭示出其他性状的变异模式更为复杂。我们还探讨了传粉者匮乏与不适宜的生境基质作为适应性进化驱动因子的作用。