We follow a genetic approach to obtain an indirect measure of reproductive population connectivity [2], [3], [14] in S. hystrix from the central to northern GBR.
Larval dispersal and reproductive population connectivity (i.e., the dispersal of individuals among subpopulations that survive to reproduce) of most marine populations is poorly understood [1], particularly for reef corals and over recent rather than evolutionary timescales [2], [3].
In Ciona populations, high levels of genetic diversity may derive from several factors, including the mutation-selection balance between the reappearing phenotypes and their elimination by natural selection, and the population genetic structure driven by reproductive strategies, geographical connectivity and effective population size.
Most metapopulation studies have focused on the ecological consequences of connectivity Given the reproductive isolation and potential for genetic drift in small isolated populations, a thorough understanding of the demographic consequences of connectivity also requires consideration of the potential evolutionary consequences [5], [6].
For most invertebrates, the reproductive age, growth rate, population density/distribution, and population connectivity remain elusive.
In a previous landscape genetic study on T. speciosissima, we suggested that substrate-mediated allopatry and temperature-dependent reproductive barriers were likely to affect temporal changes in connectivity among populations [ 10].
Our discussion is organised across three themes: (i) species selection and the sourcing of forest reproductive material; (ii) increasing resilience by fostering natural selection, ecological connectivity and species associations; and (iii) measuring the success of restoration activities.
This may be particularly true in marine species that possess a pelagic larval phase capable of dispersing larvae over large distances, and for which population densities may be influenced more by oceanographic conditions affecting connectivity and recruitment than by local environmental conditions and adult reproductive performance7,9.
Treml EA, Roberts J, Chao Y, Halpin P, Possingham HP, Riginos C (2012) Reproductive output and duration of the pelagic larval stage determine seascape-wide connectivity of marine populations.
Long periods between reproductive events (Wangen and Webster 2006), spatial heterogeneity (Hastings 1996), and variable connectivity (Floerl et al. 2009) all can contribute to the ending of the lag phase and the start of the expansion phase.
