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.

当新建生境最初被种群增长速率较快的基因型定植后，后续抵达的定植者往往难以成功建立种群。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多样性的影响。我们开展了大规模野外操控实验，旨在探究初始克隆多样性（clonal diversity）如何调控正在发育的复合种群（metapopulation）遗传结构的时间格局与景观格局。我们将专性无性繁殖的蚤状溞（Daphnia pulex）的6种基因型，以单一基因型（无克隆多样性）或多基因型组合（“高”克隆多样性）的方式，接种至新建的实验性林间池塘中。我们还在实验室中测定了所有克隆在优质与劣质两种资源条件下的种群增长速率。我们提出的预测为：在接种后的3年内，具有克隆多样性的种群相较于无克隆多样性的种群，更有可能持续存续，并表现出持久奠基者效应（persistent founder effects）的相关特征。我们预期，生长速率更快的克隆会在更多池塘中被检出，且在景观尺度下经基因型鉴定的个体中占比更高。接种后，本地与区域尺度的遗传组成均发生了显著变化。27个供试种群中有6个表现出持久奠基者效应的相关证据，且具有“高”克隆多样性的种群相较于无克隆多样性的种群，更易呈现此类效应。实验室中的生长表现无法预测野外条件下的克隆存续能力或整体优势度。因此，我们得出结论：尽管实验室测得的适合度指标未能完全解释复合种群的遗传结构，但初始克隆多样性确实提升了蚤状溞在本研究系统中的种群定植与存续能力。