Genetic evidence of Quaternary demographic changes in four rain forest tree species sampled across the Isthmus of Panama. (12th December 2012)

• Record Type: Journal Article
• Authors: Andrew Jones, F.; Cerón‐Souza, Ivania; Hardesty, Britta Denise; Dick, Christopher W.; Silman, Miles
• Is Part Of: Journal of biogeography. Volume 40:Number 4(2013:Apr.)
• Page Start: 720
• Page End: 731
• Publication Date: 2012-12-12
• Subjects: Biogeography -- Periodicals; 578.09
• DOI: 10.1111/jbi.12037
• Languages: English
• ISSNs: 0305-0270

Abstract

<abstract abstract-type="main" id="jbi12037-abs-0001"> <title>Abstract</title> <sec id="jbi12037-sec-0001" sec-type="section"> <title>Aim</title> <p>We examined and compared population genetic structure in a suite of four co‐occurring Panamanian tree species and performed coalescent‐based analyses of demographic history to evaluate hypotheses of tropical vegetation change during the Last Glacial Maximum (LGM).</p> </sec> <sec id="jbi12037-sec-0002" sec-type="section"> <title>Location</title> <p>Isthmus of Panama.</p> </sec> <sec id="jbi12037-sec-0003" sec-type="section"> <title>Methods</title> <p>Nuclear microsatellite variation was assayed in multiple populations (1179 trees, 21 locations, 6–13 locations per species) in <italic>Jacaranda copaia</italic> (Bignoniaceae), <italic>Luehea seemannii</italic> (Malvaceae), <italic>Simarouba amara</italic> (Simaroubaceae) and <italic>Symphonia globulifera</italic> (Clusiaceae). Population structure was analysed using <italic>F</italic><sub>ST</sub>‐based statistics and a Bayesian clustering approach (<sc>baps</sc>). Bayesian coalescent methods (<sc>msvar</sc>) were used to infer demographic histories.</p> </sec> <sec id="jbi12037-sec-0004" sec-type="section"> <title>Results</title> <p>High levels of genetic diversity were found in all of the species (<italic>H</italic><sub>E</sub> range, 0.56–0.79). <italic>Jacaranda copaia</italic> and <italic>L. seemannii</italic> showed lower <italic>F</italic><sub>ST</sub> and fewer Bayesian clusters across similar spatial scales than did <italic>S. globulifera</italic> and <italic>Simarouba amara</italic>. For each species examined, the current effective population sizes (<italic>N</italic><sub>e</sub>) are much lower than ancient <italic>N</italic><sub>e</sub>, within all inferred <sc>baps</sc> demes. In light‐demanding pioneer species <italic>J. copaia</italic>, <italic> L. seemannii</italic> and <italic>S. amara</italic>, estimates of the number of generations since the bottleneck events overlap with the end of the LGM (median site posterior estimates ranged from 16 to 19 ka) while <italic>Symphonia globulifera</italic> estimates are consistent with earlier population declines (median 202 ka) in the early Pleistocene and late Pliocene.</p> </sec> <sec id="jbi12037-sec-0005" sec-type="section"> <title>Main conclusions</title> <p>The wind‐dispersed deciduous species <italic>J. copaia</italic> and <italic>L. seemannii</italic> showed lower <italic>F</italic><sub>ST</sub> and spatially extensive demes, while the animal‐dispersed evergreen <italic>Symphonia globulifera</italic> and <italic>Simarouba amara</italic> showed spatially restrictive demes and higher <italic>F</italic><sub>ST</sub><sub>.</sub> Each deme examined shows evidence of historical bottlenecks. For three of the four species which are also light‐demanding pioneer species, the mean estimated time and 95% highest posterior density of the bottleneck events coincides with the end of the LGM. These results suggest that these species have undergone historical bottlenecks as a result of reduced forest cover during the Pleistocene and provide evidence of shared demographic histories among co‐occurring tropical forest trees.</p> </sec> </abstract>