Can limited dispersal or biotic interaction explain the declining abundance of the whelk, Morula marginalba, at the edge of its range?
Version of Record online: 18 JUL 2011
© 2011 The Linnean Society of London
Biological Journal of the Linnean Society
Volume 103, Issue 4, pages 849–862, August 2011
How to Cite
COULSON, L. A., PERRIN, C., ROBERTS, D. G., MINCHINTON, T. E. and AYRE, D. J. (2011), Can limited dispersal or biotic interaction explain the declining abundance of the whelk, Morula marginalba, at the edge of its range?. Biological Journal of the Linnean Society, 103: 849–862. doi: 10.1111/j.1095-8312.2011.01676.x
- Issue online: 18 JUL 2011
- Version of Record online: 18 JUL 2011
- Received 16 September 2010; revised 22 February 2011; accepted for publication 22 February 2011
- biogeographical barrier;
- East Australian Current;
- gene flow;
- genetic diversity;
- range limit;
The southern range limit of the planktotrophic, intertidal whelk, Morula marginalba, occurs immediately to the north of the south-east Australian biogeographical barrier and we predict that its range may be limited by dispersal and biotic interactions. The barrier includes several hundred kilometers without suitable habitat and is the convergence zone of major ocean currents. Within the barrier region, along-shore larval transport is expected to be erratic, with water moving offshore to form long-lived eddies. Through comparison of central and range edge populations, we test for evidence of recruitment limitation and interspecific competition with the whelk, Haustrum vinosum, which occurs sympatrically at the range edge. We found similar levels of recruitment and allozyme genetic variation within centre and edge populations where H. vinosum was absent, implying that populations are strongly interconnected. Nevertheless, recruitment and abundance of M. marginalba were lower at its extreme range limit, where it occurs with H. vinosum. Indeed, we detected significant inverse correlations between the abundance of these species, although their habitat use was similar and they consumed similar prey. These lines of evidence suggest a restricted recruitment across the barrier limits the range of M. marginalba but emphasize that multiple factors may act to set species range limits. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 103, 849–862.