The persistence of plant populations in fragmented landscapes is dependent on adequate gene flow via seed and pollen dispersal. The extent and consequences of variation in seed and fruit dispersal have been thoroughly explored from theoretical perspectives, and our knowledge of empirical seed dispersal kernels is expanding rapidly. However, the role of pollinators in counteracting seed dispersal limitation has been poorly explored and may be significant in habitats and landscapes where pollinator limitation represents a constraint on maintenance of genetic diversity and the persistence of plant populations. Our research has documented a trade-off among closely related coexisting tropical tree species between flower size and flower number that may represent a fundamental constraint on the boundaries of flower trait evolution (Kettle et al. 2011). In this system, small-flowered species are pollinated by relatively immobile pollinators with small body size and dispersal capacity. Therefore, although these species produce a vast number of small flowers, mean pollen dispersal distances tend to be low and a high proportion of mating events occur between related individuals, leading to high abortion rates during seed development. Related species with larger flowers generally attract larger insect pollinators that disperse over greater distances and generate much broader pollen dispersal kernels and a lower likelihood of sib-sib mating events. Therefore, for these species, the greater likelihood of successful pollination and seed maturation offsets their lower production of flowers, which equalizes reproductive output despite wide variation in flower size, pollinator size and pollen dispersal distance.
This trade-off has been identified in one study system, but the generality of these patterns and their implications for conservation of plants in fragmented landscapes are poorly known. This project will use spatially explicit demographic and foraging models (Bocedi et al. 2021, Nicholson et al. 2019) to explore the drivers underlying the evolution of flower trait variation and test the implications of these trade-offs for the maintenance of genetic diversity and population persistence in spatially heterogeneous fragmented landscapes.
Example questions. Do specific trait values or combinations of traits predict differences in fine-scale spatial genetic structure and the likelihood of sib-sib mating among species? How does habitat fragmentation affect pollen dispersal and maintenance of genetic diversity for species with different trait values? Are some species more tolerant of the genetic implications of habitat fragmentation than others, and how can these vulnerabilities be offset by restoration of habitat connectivity and gene flow?
Training. Training will be provided in the use and development of relevant modelling platforms and the statistical approaches required for data synthesis and analyses. To parameterise and validate the models there may be opportunities for fieldwork in a tropical forest environment and collection of genomic data from plants and their pollinators. Training will be provided in preparation for fieldwork and laboratory analyses.
Candidate Background: The successful candidate is expected to have skills and experience in biological or environmental science, including training in quantitative methods. Experience in ecological modelling, bioinformatics and fieldwork is desirable.
More project details are available here: https://www.quadrat.ac.uk/quadrat-projects/
How to apply: https://www.quadrat.ac.uk/how-to-apply/
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