Premium
Long‐term population isolation in the endangered tropical tree species Caesalpinia echinata Lam. revealed by chloroplast microsatellites
Author(s) -
Lira C. F.,
Cardoso S. R. S.,
Ferreira P. C. G.,
Cardoso M. A.,
Provan J.
Publication year - 2003
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 - 10.1046/j.1365-294x.2003.01991.x
Subject(s) - biology , genetic diversity , endangered species , ecology , habitat fragmentation , gene flow , population , caesalpinia , isolation by distance , range (aeronautics) , genetic variation , biodiversity , habitat , evolutionary biology , genetics , demography , materials science , sociology , gene , composite material
Habitat fragmentation represents the single most serious threat to the survival of tropical ecosystems. In formulating strategies to counteract the detrimental effects of fragmentation, knowledge of the levels and patterns of genetic diversity within and between natural populations is vital to the establishment of any conservation programme. We utilized polymorphic chloroplast microsatellite markers to analyse genetic diversity in populations of the endangered tropical tree Caesalpinia echinata Lam. representing the entire extant range of the species. Levels of within‐population diversity were low, with only two of seven populations studied displaying any variation. The vast majority of the genetic variation was partitioned between geographical regions (36%) and between populations within regions (55%). These levels of genetic structuring, coupled with a calculated pollen‐to‐seed flow ratio of ≈ 6.7:1, suggest that there has been little gene flow between the three major geographical regions over an extended period. Thus, the current tripartite distribution of the species is more consistent with the existence of separate glacial refugia, rather than reflecting any anthropogenic effects.