RT Journal Article
SR Electronic
T1 Species dispersal mediates opposing influences of a branching network on genetic variation in a metapopulation
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 550194
DO 10.1101/550194
A1 Ming-Chih Chiu
A1 Bin Li
A1 Kei Nukazawa
A1 Thaddeus Carvajal
A1 Kozo Watanabe
YR 2019
UL http://biorxiv.org/content/early/2019/02/14/550194.abstract
AB In nature, ubiquitous fractal networks can have two but opposing influences, by increasing distal and confluent habitats, respectively, under raising branching complexity on metapopulations’ genetic structure, although this remains poorly understood, particularly regarding the roles of species-specific traits. In this study, we evaluated the integrated influences of network complexity and species dispersal mode/ability on genetic divergence among populations at the catchment scale, using a theoretical framework with empirical genetic data from four sympatric stream macroinvertebrate species. Empirical patterns of spatial genetic structure were attributed to dispersal ability and the species’ habitat specialisation levels. Our theoretical evidence showed that both greater landscape connectivity (via shorter watercourse distance) and greater isolation of distal habitats (e.g. headwater streams) occur in the more-branched networks. These two spatial features have negative and positve influences on genetic divergence, respectively, with their relative importance varying in different species. Watersheds harbouring a higher number of local populations have larger genetic divergence of metapopulations. Downstream- and upstream-biased asymmetric dispersals dictate increases and declines, respectively, in genetic divergence. In addition, distal populations (e.g. in headwaters) have higher genetic independence between themselves under higher levels of downstream-biased asymmetry. A strong association between species features and evolutionary processes (gene flow and genetic drift) mediates the pervasive influences of branching complexity on metapopulation genetic divergence, which highlights the importance of considering species dispersal patterns when developing management strategies in rapid environmental change scenarios.