Data from: Consequences of extensive habitat fragmentation in landscape-level patterns of genetic diversity and structure in the Mediterranean esparto grasshopper

Anthropogenic habitat fragmentation has altered the distribution and population sizes in many organisms worldwide. For this reason, understanding the demographic and genetic consequences of this process is necessary to predict the fate of populations and establish management practices aimed to ensure their viability. In this study, we analyse whether the spatial configuration of remnant semi-natural habitat patches within a chronically fragmented landscape has shaped the patterns of genetic diversity and structure in the habitat-specialist esparto grasshopper (Ramburiella hispanica). In particular, we predict that agricultural lands constitute barriers to gene flow and hypothesize that fragmentation has restricted inter-population dispersal and reduced local levels of genetic diversity. Our results confirmed the expectation that isolation and habitat fragmentation have reduced the genetic diversity of local populations. Landscape genetic analyses based on circuit theory showed that agricultural land offers ~1000 times more resistance to gene flow than semi-natural habitats, indicating that patterns of dispersal are constrained by the spatial configuration of remnant patches of suitable habitat. Overall, this study shows that semi-natural habitat patches act as corridors for inter-population gene flow and should be preserved due to the disproportionately large ecological function that they provide considering their insignificant area within these human-modified landscapes.

人为栖息地破碎化已改变了全球众多生物类群的分布格局与种群规模。正因如此，解析该过程带来的种群统计与遗传效应，对于预测种群存续命运、制定保障种群存续的管理策略至关重要。本研究以生境专性物种针茅蚱蜢（Ramburiella hispanica）为研究对象，探究长期破碎化景观内残存半自然生境斑块的空间构型，是否塑造了其遗传多样性与遗传结构格局。具体而言，我们提出两项假设：农田会成为基因交流的障碍，而生境破碎化会限制种群间扩散并降低局域种群的遗传多样性水平。本研究结果证实了这一预期：生境隔离与破碎化降低了局域种群的遗传多样性。基于电路理论的景观遗传分析显示，农田对基因交流的阻力约为半自然生境的1000倍，这表明扩散格局受到适宜生境残存斑块的空间构型制约。综上，本研究表明：半自然生境斑块可作为种群间基因交流的廊道，尽管其在人为改造景观中占比极低，却发挥着远超其面积占比的生态功能，因此亟需加以保护。