Next generation conservation genetics at sea: detecting and conserving adaptive potential
Background: Kelp forests are amongst the world’s most productive and extensive habitats, rivalling the productivity of tropical rainforests. Kelp is a ‘foundation’ species, actually forming the habitat for the community of species that live in kelp forests. As a foundation species, kelp underpins entire coastal ecosystems and forms the basis for coastal resources providing essential ecological goods and services (e.g. commercial fisheries, nutrient cycling and shoreline protection). However, the mechanisms by which the diversity and function of these communities are linked to the diversity of foundation species (both within and between species) are not well understood. Work in the newly emerging fields of ‘eco-evolutionary dynamics’ and ‘community genetics’ is showing that evolutionary and ecological processes can operate on the same short (e.g. decadal) time scales as those most relevant to conservation and management, implying that understanding how these processes interact is essential for effective management1. Recent studies have shown that genetic variation in foundation species of plants (such as a forest tree species) can be an important driver of ecosystem species diversity, and of genetic diversity for individual community species2, but most of these studies have been in terrestrial ecosystems. Genetic diversity is known to influence ecological processes including productivity, resilience and competitive ability (e.g.3,4). At the same time, effective population size (Ne), natural selection and the degree of connectivity among populations influence the level and patterns of biodiversity.
Objectives: The primary objective of the study will be to better understand the mechanisms that determine community structure in coastal marine ecosystems. To that end the student will address 3 key questions: (1) Will the levels of genetic diversity for the foundation species and its associated fauna covary? (2) Does the genetic diversity of foundation species influence the level of functional and species diversity in marine communities or is this instead primarily determined by ocean circulation? (3) Do biotic interactions among species influence the genetic structuring of variation in individual species at loci under selection?
Methodology: The student will study genomic diversity for one foundation species (Laminaria digitata) and 3 associated herbivore species (all gastropods with varying levels of dependency on L. digitata). Genome sampling (ddRAD5) will be used to assess diversity and connectivity among putative populations at single nucleotide polymorphic (SNP) markers comparing 4 putative populations per species. These data will provide information on population structure, effective population size, local diversity and directional patterns of gene flow, and comparative levels of neutral and functional diversity between host and community species. Inference requires genetic differentiation among foundation species populations, and differences in the level of diversity, as has been seen for differentiated L. digitata populations in Britany 30-60km apart6. Bayesian models will be used to help assess the relative influence of biotic (e.g. the interaction between community and host species) and abiotic (e.g. ocean circulation) factors on patterns of genetic diversity. The study will be conducted in a region where ocean circulation models and data are available, and all species to be sampled are easily accessible within the intertidal zone.
This is a competitive studentship through the Durham Doctoral Studentship program, providing full funding for tuition, living expenses and research expenses. For further details please contact Rus Hoelzel ([email protected]). Application materials should include a cv, academic records and at least two letters of reference sent to [email protected]
References: 1) Hendry (2016) Eco-Evolutionary dynamics, Princeton University Press; 2) Lau, et al. (2016) Ecology 97, 733–742; 3) Hughes et al. (2008) Ecol. Lett. 11, 609-623; 4) Roger et al. (2012) PLoS ONE 7, e45007; 5) Peterson et al. (2012) PLoS ONE 7, e37135; 6) Robuchon et al. (2014) Mol. Ecol. 23, 2669-2685.