Data from: Initial genetic diversity enhances population establishment and alters genetic structuring of a newly established Daphnia metapopulation

When newly created habitats are initially colonized by genotypes with rapid population growth rates, later arriving colonists may be prevented from establishing. Although these priority effects have been documented in multiple systems, their duration may be influenced by the diversity of the founding population. We conducted a large-scale field manipulation to investigate how initial clonal diversity influences temporal and landscape patterns of genetic structure in a developing metapopulation. Six genotypes of obligately asexual Daphnia pulex were stocked alone (no clonal diversity) or in combination (‘high’ clonal diversity) into newly created experimental woodland ponds. We also measured the population growth rate of all clones in the laboratory when raised on higher-quality and lower-quality resources. Our predictions were that in the 3 years following stocking, clonally diverse populations would be more likely to persist than nonclonally diverse populations and exhibit evidence for persistent founder effects. We expected that faster growing clones would be found in more pools and comprise a greater proportion of individuals genotyped from the landscape. Genetic composition, both locally and regionally, changed significantly following stocking. Six of 27 populations exhibited evidence for persistent founder effects, and populations stocked with ‘high’ clonal diversity were more likely to exhibit these effects than nonclonally diverse populations. Performance in the laboratory was not predictive of clonal persistence or overall dominance in the field. Hence, we conclude that although laboratory estimates of fitness did not fully explain metapopulation genetic structure, initial clonal diversity did enhance D. pulex population establishment and persistence in this system.

当新建生境最初被具有快速种群增长速率的基因型定植后，后续抵达的定植者可能无法成功建立种群。尽管这类优先效应（priority effects）已在多个研究系统中被报道，但其持续时长可能受奠基种群（founding population）多样性的影响。本研究开展了大规模野外操控实验，以探究初始克隆多样性如何调控正在形成的集合种群（metapopulation）遗传结构的时间与景观格局。我们将6种专性无性生殖的蚤状溞（Daphnia pulex）基因型单独投放（无克隆多样性）或混合投放（即高克隆多样性组）至新建的实验性林间池塘中。我们还在实验室中，分别以高质量与低质量饵料培养所有克隆株系，测定其种群增长速率。我们提出如下研究预期：在投放后的3年内，具有克隆多样性的种群相较于无克隆多样性种群更易持续存续，且会呈现持续性奠基效应（founder effects）的相关证据；我们同时预期，生长速率更快的克隆株系会在更多池塘中被检出，且在全域采样的基因分型个体中占比更高。投放后，种群的遗传组成在局域与区域尺度均发生了显著变化。27个研究种群中有6个呈现出持续性奠基效应的相关证据，且高克隆多样性组的投放种群相比无克隆多样性组种群，更易表现出这类效应。实验室测得的生长表现无法预测克隆株系在野外的存续能力与整体优势度。因此，我们得出结论：尽管实验室测得的适合度无法完全解释集合种群的遗传结构，但初始克隆多样性确实提升了蚤状溞（Daphnia pulex）在本研究系统中的种群建立与存续能力。