Open AccessGenetic differentiation of Baetis alpinus Pictet (Ephemeroptera: Baetidae) in fragmented alpine streams
Author(s) -
Monaghan Michael T.,
Spaak Piet,
Robinson Christopher T.,
Ward J. V.
Publication year - 2001
Publication title -
heredity
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.441
H-Index - 118
eISSN - 1365-2540
pISSN - 0018-067X
DOI - 10.1046/j.1365-2540.2001.00843.x
Subject(s) - gene flow , biology , baetidae , streams , ecology , genetic structure , habitat , population , genetic divergence , population genetics , genetic variation , gene , genetic diversity , invertebrate , computer network , biochemistry , demography , sociology , computer science
The interpretation of low F ST values as evidence of high levels of gene flow among habitat fragments may be confounded by population genetic structures that are indicative of historical rather than present‐day levels of gene flow. We examined the genetic structure of 23 populations of Baetis alpinus (Insecta: Ephemeroptera) living in alpine streams fragmented by lakes (≈10 000 years old), reservoirs (≈100 years old), and in nonfragmented streams, to examine if lakes act as barriers to gene flow and to investigate the temporal resolution of allozyme markers. Estimates of gene flow indicated little or no genetic divergence along four nonfragmented reference streams and across two lakes and two reservoirs ( F ST =0.004–0.041), but marked differentiation across four lakes ( F ST =0.092–0.362) and across one reservoir that was a lake enlarged by a dam ( F ST =0.075). Differentiation was unrelated to distance between fragments, but occurred only in lakes found in valleys that have been ice‐free throughout the Holocene. We suggest that standing water bodies act as barriers to gene flow in B. alpinus and that low F ST values observed between fragments separated by reservoirs do not indicate high levels of gene flow but rather show that genetic differentiation was not detectable within the first 100–1000 years of habitat fragmentation.