The levels of genetic connectivity among populations of marine organisms around the New Zealand coast are a key parameter for conservation. They can be crucial in providing adequate management of exploited species, marine protection for threatened species and an understanding of the inter-dependence of marine protected areas. Our aim is to address this issue by taking a community perspective of connectivity rather than simply a species-by-species view. By simultaneously examining the genetic population structure of a diverse range of coastal species we can ascertain if there are common locations where connectivity is either restricted or promoted.
As a first step in this project, we examined connectivity among populations of two New Zealand endemic intertidal species with differing larval dispersal potentials. We used mitochondrial cytochrome oxidase I (COI) and nuclear ITS DNA sequences to investigate the population genetic and phylogeographic structure of the cat´s eye snail (Lunella smaragdus) and half crab (Petrolisthes elongatus) in order to determine: (1) if they exhibit geographic restrictions to genetic connectivity and if so, where and (2) if they follow one of the common patterns of connectivity previously displayed by other species.
These two species differ significantly in both their dispersal abilities and their patterns of connectivity. Both animals show some degree of genetic discontinuity between the North and South Islands, concordant with other taxonomically and ecologically different species. However they also show some idiosyncratic patterns of gene flow. The data from these species are now being compared with previously published genetic datasets to ascertain if common dispersal barriers are present around New Zealand.