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Is Older Better? Evolutionary Constraints on Biodiversity and Ecosystem Function

Supervisor: Andrew Tanentzap

Reference Code: B138

Importance of the area of research: Priority effects predict that individuals of a species that arrive into a new habitat earlier have precedence over ecological niche space and can diversify across a range of habitats (Lee et al. 2012).  Thus, older lineages might have greater range sizes and be less likely to become locally extinct.  But this has rarely been tested (Wang et al. 2013).  Communities comprised of older species might have also had more time to co-evolve interactions that deliver important functions and services.  This is one reason why conservation biology promotes the protection of native over exotic species.

What the project will involve: We will relate the evolutionary age of species and vegetation types to their abundance patterns and functioning.  First, we will use large-scale datasets to test whether the phylogenetic age of species increases local abundance and range size.  Second, we will relate the ages of dryland and wetland vegetation communities in existing datasets to their levels of primary production, litter decomposition, and nutrient cycling.  Finally, we will use a mesocosm experiment to test our findings experimentally (e.g. Gravel et al. 2013).

What the student will do: The student will collate published datasets and analyze data using statistical models.  Time-calibrated molecular phylogenies will be estimated for some of the datasets using publically available DNA sequences, and where necessary, samples will be sequenced by the student.  The student will also design and execute experiments, collecting biodiversity and ecosystem function data and interpreting results. 

Training that will be provided: The student will be given training in statistical modeling, comparative phylogenetic methods, and experimental design, though the ideal will already applicant have experience in these areas.  To help prepare samples for sequencing, training in basic molecular biology will be provided in the Department.  Instruction on scientific writing is essential and will also be provided.

References:

  1. Gravel, D. et al. 2012. Phylogenetic constraints on ecosystem functioning.  Nature Communications, vol. 3, pp.1117.
  2. Lee, W.G., Tanentzap, A.J. & Heenan, P.B. 2012. Plant radiation history affects community assembly: evidence from the New Zealand alpine. Biology Letters, vol. 23, pp.558–561. 
  3. Wang, S. et al. 2013. Why abundant tropical tree species are phylogenetically old. Proceedings of the National Academy of Sciences, vol. 110, pp.16039–16043.