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Author: Sunnucks, P.; Blacket, M. J.; Taylor, J. M.;
Sands, C. J.; Ciavaglia, S. A.; Garrick, R. C.; Tait, N. N.; Rowell, D. M.;
Pavlova, A.
Year: 2006
Title: A tale of two flatties: different responses of
two terrestrial flatworms to past environmental climatic fluctuations at
Tallaganda in montane southeastern Australia
Journal: Molecular Ecology
Volume: 15
Pages: 4513-4531
Date: Dec
Abstract: Comparative phylogeographic studies of
animals with low mobility and/or high habitat specificity remain rare, yet such
organisms may hold fine-grained palaeoecological signal. Comparisons of
multiple, codistributed species can elucidate major historical events. As part
of a multitaxon programme, mitochondrial cytochrome oxidase I (COI) variation
was analysed in two species of terrestrial flatworm, Artioposthia lucasi and
Caenoplana coerulea. We applied coalescent demographic estimators and nested
clade analysis to examine responses to past, landscape-scale, cooling-drying
events in a model system of montane forest (Tallaganda). Correspondence of
haplotype groups in both species to previously proposed microbiogeographic regions
indicates at least four refuges from cool, dry conditions. The region predicted
to hold the highest quality refuges (the Eastern Slopes Region), is indicated
to have been a long-term refuge in both species, but so are several other
regions. Coalescent analyses suggest that populations of A. lucasi are
declining, while C. coerulea is expanding, although stronger population
substructure in the former could yield similar patterns in the data. The
differences in spatial and temporal genetic variation in the two species could
be explained by differences in ecological attributes: A. lucasi is predicted to
have lower dispersal ability but may be better able to withstand cold
conditions. Thus, different contemporary population dynamics may reflect
different responses to recent (Holocene) climate warming. The two species show
highly congruent patterns of catchment-based local genetic endemism with one
another and with previously studied slime-mould grazing Collembola.
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