The Interplay of abiotic and biotic factors as drivers of biodiversity changes across space and time
Darwin’s works and the evolutionary synthesis have led to a clear consensus that ecological and evolutionary processes are inextricably linked1. However, until recently they were thought to operate on very different time scales. This view has changed radically with the recent development of the fields of eco-evolutionary dynamics and community genetics. These fields seek to unify evolution and ecology into a common conceptual framework focusing on rapid and dynamic environmental and evolutionary change operating on short time scales. Most recent advances have been focused on terrestrial communities2. These studies show that genotypic variation in foundation species of plants is an important driver of community diversity and that genetics-based interactions of a few strongly interacting species can determine the structure of a much larger community3. Based on these terrestrial studies it has been proposed that a “genetic filter” may play an important role in community assembly4. However, an alternative “neutral” point of view posits that ecological and evolutionary changes are driven by neutral processes and that apparent associations between genetic and species diversity is the result of equivalent mechanisms that operate independently at the two levels of biological organisation. At the genetic level these mechanisms include mutation, drift and migration while at the ecological level the only difference is that mutation is replaced by speciation. These two points of view represent extremes along a continuum mediated by the importance of spatial processes, whereby the genetic filter due to interspecific interactions is very important under scenarios of low environmental stochasticity but becomes less important as stochasticity increases. For example, in the marine environment strong and asymmetric physical flows over a very extended and heterogeneous habitat matrix exacerbate the importance of spatial processes5. Moreover, there is extensive temporal variability in ocean circulation patterns, which can include flow reversals even along straight coastlines6. These characteristics suggest that dispersal and abiotic filters may dominate marine community assembly, limiting the importance of genetic filters. Although it is accepted that the interplay between abiotic and biotic factors is likely to be very important for eco-evolutionary dynamics and associations between different levels of biodiversity, there is a lack of clear understanding of the mechanisms involved and their expected outcomes.
The overall aim of the thesis is to investigate the mechanisms underlying the eco-evolutionary dynamics of communities composed by a foundation species and its associated fauna. This will be done by addressing the following specific questions:
(1) Do coupled patterns of population stability/instability generate covarying levels of genetic diversity across foundation species and its associated fauna?
(2) Are patterns of genetic diversity among conspecific populations primarily determined by abiotic factors (e.g. ocean circulation)?
(3) What particular mechanism can allow the genetic diversity of foundation species to influence the level of functional and species diversity in marine communities, or the genetic diversity of individual herbivore species?
(4) Can interspecific interactions influence the genetic structuring of variation in individual species at loci putatively under selection?
(5) What is the potential effect of global change on the distribution and functioning of coastal ecosystems?
The thesis will investigate this problem in the first instance using an eco-evolutionary simulation framework in order to develop hypothesis about the mechanisms involved. These hypotheses will then be tested with existing databases covering both genetic and specific diversity as well as environmental databases for several ecosystems. Two such databases are already available through collaborations; one covers the Hawaiian coral reef ecosystem and the other covers upland river drainages in Wales. Several other databases exist in online repositories and they will be queried to find equivalent data for terrestrial ecosystems.
This funding opportunity is only available to Chinese nationals who are applying through the Chinese Scholarship Council.
A minimum level of English language ability of CEFR B2+ to C1 (IELTS 6.5 to 7.5 or an equivalent score in another English language test) is required.
Scholarships provide full tuition fees and local research costs for 48 months of full-time study.
The China Scholarship Council will cover the living costs to include accommodation and subsistence, return international airfare to the UK, together with passport and visa application fees.
1 Hendry (2016) Eco-Evolutionary dynamics, Princeton University Press
2 Whitham et al. (2012) Trends in plant sciences 17, 271-281
3 Lau MK, et al. (2016) Ecology 97, 733–742
4 Gugerli et al. (2013) Mol. Ecol. 22, 3198-3207
5 Kinlan, BP, Gaines SD (2003) Ecology 84, 2007-2020
6 Gaylord B, Gaines SD (2000) Am Nat 155,769–789.
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FTE Category A staff submitted: 50.45
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