2017_75: Phylogenetic diversity and structure in
Neotropical biomes
Supervisors: Dr Eve Lucas ([email protected]), Dr Cristina Banks-Leite (Life
Sciences) and Dr Eimear Nic Lughadha (RBG Kew)
Department: Royal Botanical Gardens (Kew) / Life Sciences
Assessment of phylogenetic diversity (PD) and structure (phylo-structure) of
environments allows inference of past evolutionary drivers of speciation and extinction
and prediction of the effects of future climate change. PD and PS have been studied
using phylogenies of plant communities (e.g. Moro et al. 2015: PLOSone.
doi:10.1371/journal.pone.0119166) and of individual biotic groups (Pugliesi & Rapini,
Int. J. Biodiv. DOI: 10.1155/2015/758019). This study will use phylogenetic trees of
ecologically significant higher plant groups to compare centres of phylogenetic
diversity and their phylogenetic structure (e.g. Cavender-Bares, 2009: Ecol. Lett. doi:
10.1111/j.1461-0248.2009.01314.x; Faith, 2016: Biodiv. Cons. Phyl. Syst. DOI
10.1007/978-3-319-22461-9_7). Interpretation of results will include implications for
conservation strategies.
To date the majority of studies examining phylogenetic structure over environmental
gradients in tropical plant communities have focused on climate, while a few examine
other gradients such as soil fertility or luminosity (Lehtonen et al. 2015: Global Ecol.
Biogeogr. DOI: 10.1111/geb.12294). Biome-wide studies based on community
samples (e.g. from floristic or phytosociological surveys) have revealed broad-scale
correlations between ecological factors and phylogenetic structure (e.g. Moro et al.
2015: PLOSone. doi:10.1371/journal.pone.0119166; Dexter et al. in press: PeerJ.
DOI: 10.7717/peerj.2402.). There is a need to complement this work with studies of
clades for which more fine-grained data on functional traits, ecology and extinction risk
are available for inclusion in analyses along with systematic and phylogenetic data.
Study groups are large genera of Myrtaceae and Leguminosae, two of the most
ecologically important and species-rich woody families of the Neotropics. The study
will test the following hypotheses, comparing results from Neotropical Campos
Rupestres (CR) and the Atlantic forest (AF) biome.
For more information on how to apply visit us at www.imperial.ac.uk/changingplanet
Science and Solutions for a Changing Planet
H1: Extinction risk is higher for young, fast evolving plant lineages i.e. the most
threatened species cluster within short branches at phylogeny tips (Davies et al. 2011:
PLOS. DOI 10.1371/journal.pbio.1000620).
H2: PD is greater in areas that have been climatically stable for longer (Staggemeier
et al. 2015: Ann. Bot. doi:10.1093/aob/mcv005).
H3: The degree of phylogenetic clustering of species in CR assemblages is greater
than in AF assemblages reflecting the relative importance of competition and
environmental filtering (Pugliesi & Rapini, Int. J. Biodiv. DOI: 10.1155/2015/758019).
H4. Habitat fragmentation results in more phylogenetically clustered communities due
to intensified environmental filtering.
To address Hypothesis 1 the student will assemble dated super-trees of the study
groups from existing DNA sequence data supplemented with newly generated data.
Existing extinction risk assessments will be collated and supplemented with
preliminary assessments calculated for species not previously assessed; phylogenetic
signal of extinction risk will be measured using existing packages in R (e.g. Stefanaki
et al. 2015: PLOSone. doi:10.1371/journal.pone.0138414). To address hypotheses 2,
3 and 4, study areas will be divided into grid squares for which PD and phylo-structure
metrics will be calculated. For hypothesis 2, PD of squares within and outside
postulated climatic refugia will be contrasted. For hypotheses 3 and 4, phylo-structure
of grid squares will be correlated with vegetation structure and habitat fragmentation
indices from sources including remote-sensing data. Fieldwork, subject to funding,
would ground-truth existing data for selected gridsquares.
For more information on how to apply visit us at www.imperial.ac.uk/changingplanet