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Diversification in a biodiversity hot spot: landscape correlates of phylogeographic patterns in the A frican spotted reed frog
Author(s) -
Lawson Lucinda P.
Publication year - 2013
Publication title -
molecular ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.619
H-Index - 225
eISSN - 1365-294X
pISSN - 0962-1083
DOI - 10.1111/mec.12229
Subject(s) - biological dispersal , ecology , phylogeography , isolation by distance , biodiversity , biology , population , genetic diversity , genetic structure , local adaptation , habitat , intraspecific competition , geographical distance , geography , biochemistry , demography , sociology , gene , phylogenetic tree
The E astern A fromontane B iodiversity H otspot is known for microendemism and exceptional population genetic structure. The region's landscape heterogeneity is thought to limit gene flow between fragmented populations and create opportunities for regional adaptation, but the processes involved are poorly understood. Using a combination of phylogeographic analyses and circuit theory, I investigate how characteristics of landscape heterogeneity including regional distributions of slope, rivers and streams, habitat and hydrological basins (drainages) impact genetic distance among populations of the endemic spotted reed frog ( H yperolius substriatus ), identifying corridors of connectivity as well as barriers to dispersal. Results show that genetic distance among populations is most strongly correlated to regional and local hydrologic structure and the distribution of suitable habitat corridors, not isolation by distance. Contrary to expectations, phylogeographic structure is not coincident with the two montane systems, but instead corresponds to the split between the region's two major hydrological basins ( Z ambezi and E ast C entral C oastal). This results in a paraphyletic relationship for the M alawian Highlands populations with respect to the E astern A rc M ountains and implies that the northern M alawian Highlands are the diversity centre for H . substriatus . Although the M alawian Highlands collectively hold the greatest genetic diversity, individual populations have lower diversity than their E astern A rc counterparts, with an overall pattern of decreasing population diversity from north to south. Through the study of intraspecific differentiation across a mosaic of ecosystem and geographic heterogeneity, we gain insight into the processes of diversification and a broader understanding of the role of landscape in evolution.