Data from: Contrasting insights provided by single and multispecies data in a regional comparative phylogeographic study

Many single-species freshwater phylogeographic studies have been carried out in south-east Queensland; however comparative phylogeography requires multiple lines of evidence to infer deep, significant relationships between landscape and biota. The present study aimed to test conclusions resulting from single taxon studies in a multispecies comparative framework: (1) how influential are river basins in the genetic structure of freshwater species; (2) are there biogeographic frontiers between groups of basins; and (3) could deep intraspecific lineages be explained by a single event? New and existing data from 33 freshwater species (23 fishes and 10 crustaceans) were combined, and both standard single-species analyses (haplotype networks, genetic distances, ΦST) and multispecies methods (hierarchical ABC) were carried out for 1814 sequences from eight basins. More than half of the species displayed a high phylogeographic structure and contained at least two distinct lineages. Almost all of the lineage divergences displayed an element of north/south geographic breaks, with the most influential boundary being between the Mary and Brisbane rivers. Of the 11 basin-pair multispecies coalescent analyses, four implied a single divergence as being most likely. A regional analysis of deep lineages within 16 taxon-pairs resulted in a strongly supported inference of a single divergence, probably dating to the Pleistocene. Basin boundaries are a key determinant of phylogeographic patterns for most of these freshwater species, although the specific biogeographic relationship between basins often varies depending on the species. There are a number of influential biogeographic frontiers, with the Brisbane-Mary being the most important. The finding that a single event may be responsible for multiple deep lineages across the region implies that a highly influential climate change event may have been detected.

昆士兰州东南部已开展诸多单物种淡水系统生物地理学（phylogeography）研究；但比较系统生物地理学（comparative phylogeography）研究需依托多维度证据，方能推断景观与生物群落间的深层显著关联。本研究旨在依托多物种比较框架，对单类群研究的结论进行验证：（1）流域对淡水物种的遗传结构有多大影响？（2）不同流域组之间是否存在生物地理分界？（3）深层种内谱系能否用单一事件解释？研究整合了33个淡水物种（23种鱼类与10种甲壳类）的新增与已有数据，针对8个流域的1814条序列，同步开展了标准单物种分析（单倍型网络（haplotype networks）、遗传距离（genetic distances）、ΦST）与多物种方法（分层近似贝叶斯计算（hierarchical Approximate Bayesian Computation, ABC））。超半数物种表现出较强的系统生物地理学结构，且至少包含两个独立谱系。几乎所有谱系分化均表现出南北地理阻隔特征，其中最具影响力的分界位于马里河与布里斯班河之间。在针对11个流域对的多物种溯祖分析中，有4项结果支持单一分化事件为最合理的推断。对16个类群对的深层谱系进行区域分析后，得到了强有力的支持性推论：单一分化事件大概率发生于更新世（Pleistocene）。尽管不同物种间的流域间生物地理关系往往存在差异，但流域边界仍是多数此类淡水物种系统生物地理学格局的关键决定因素。区域内存在多处具有重要影响的生物地理分界，其中以布里斯班-马里河分界最为关键。本研究发现区域内多处深层谱系可能由单一事件所致，这意味着我们或已检测到一次影响深远的气候变化事件。