Conservation implications of complex population structure: lessons from the loggerhead turtle (Caretta caretta)
Complex population structure can result from either sex‐biased gene flow or population overlap during migrations. Loggerhead turtles (Caretta caretta) have both traits, providing an instructive case history for wildlife management. Based on surveys of maternally inherited mtDNA, pelagic post‐hatchli...
Saved in:
Published in | Molecular ecology Vol. 14; no. 8; pp. 2389 - 2402 |
---|---|
Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
Oxford, UK
Blackwell Science Ltd
01.07.2005
Blackwell Publishing Ltd |
Subjects | |
Online Access | Get full text |
Cover
Loading…
Summary: | Complex population structure can result from either sex‐biased gene flow or population overlap during migrations. Loggerhead turtles (Caretta caretta) have both traits, providing an instructive case history for wildlife management. Based on surveys of maternally inherited mtDNA, pelagic post‐hatchlings show no population structure across the northern Atlantic (φST < 0.001, P = 0.919), subadults in coastal habitat show low structure among locations (φST = 0.01, P < 0.005), and nesting colonies along the southeastern coast of the United States have strong structure (φST = 0.42, P < 0.001). Thus the level of population structure increases through progressive life history stages. In contrast, a survey of biparentally inherited microsatellite DNA shows no significant population structure: RST < 0.001; FST = 0.002 (P > 0.05) across the same nesting colonies. These results indicate that loggerhead females home faithfully to their natal nesting colony, but males provide an avenue of gene flow between regional nesting colonies, probably via opportunistic mating in migratory corridors. As a result, all breeding populations in the southeastern United States have similar levels of microsatellite diversity (HE = 0.70–0.89), whereas mtDNA haplotype diversity varies dramatically (h = 0.00–0.66). Under a conventional interpretation of the nuclear DNA data, the entire southeastern United States would be regarded as a single management unit, yet the mtDNA data indicate multiple isolated populations. This complex population structure mandates a different management strategy at each life stage. Perturbations to pelagic juveniles will have a diffuse impact on Atlantic nesting colonies, mortality of subadults will have a more focused impact on nearby breeding populations, and disturbances to adults will have pinpoint impact on corresponding breeding populations. These findings demonstrate that surveys of multiple life stages are desirable to resolve management units in migratory marine species. |
---|---|
Bibliography: | ark:/67375/WNG-L7QVLPJG-S istex:6BC7CE61D9E517DF9D702126DD3661DC2B54C41A ArticleID:MEC2598 ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 ObjectType-Article-1 ObjectType-Feature-2 |
ISSN: | 0962-1083 1365-294X |
DOI: | 10.1111/j.1365-294X.2005.02598.x |