My research is focussed around three major and interlocking themes. The first is understanding large-scale patterns of diversity in tropical rain forests, the second is linking above- and below-ground functioning in these forests and the third is to ascertain the effects of anthropogenically-induced disturbances on the above. This includes current collaborative research to understand factors shaping tree diversity and carbon storage in forests of Borneo, linking above-ground tree diversity to below-ground mycorrhizal fungal diversity, and looking at the effects of droughts on microbial functioning in tropical soils. My approach uses both simple (quadrats and tape-measures) and state-of-the-art (isotopic analyses and molecular DNA community profiling) methods to answer the questions of interest.
Current Projects
Arbuscular mycorrhizal community composition in forests of French Guiana
We showed that the arbuscular mycorrhizal fungal community was similar among three leguminous host tree species using a DGGE and cloning approach in the highly diverse lowland tropical forest. This is being followed up by examining successional development of the mycorrhizal community on the rock savannah using the latest pyrosequencing techniques.
- With Dr. David Elliott & Dr. Robin Sen (Manchester Metropolitan University) & Dr Fritz Oehl (Agroscope, Switzerland)
- Funded by Centre Nationale de la Recherche Scientifique.
Isotopic approaches to measure carbon and nitrogen cycling in montane forests of Jamaica
A study of nitrogen cycling was made between two forest types in the Blue Mountains of Jamaica. The 'mor ridge' forest is highly nitrogen deficient when compared with the 'mull ridge' forest. Furthermore, it appears that whilst nitrate is being produced in these soils, many of the trees have a preference for ammonium use.
- With Dr. Ed Tanner (University of Cambridge).
- Funded by British Ecological Society and others.
- With Dr. Ed Tanner (University of Cambridge).
- Funded by British Ecological Society and others.
Long-term monitoring of tree growth rates, secondary succession and phenology at Barito Ulu, Central Borneo
We now have over 15 years data on tree growth rates in permanent plots in both primary forest and secondary forest of various ages as well as plant reproductive phenological data from a similar time period.
Secondary forests chronosequences are useful but do not fully describe the successional process due to the quite divergent early stages of succession which appear to converge at later stages.
Tree growth rates are greater in lowland evergreen forests than heath forests for larger trees but are actually greater in heath forests for smaller (< 20 cm dbh) trees, probably due to the lower canopy.
- Various funders (starting from sponsors of two undergraduate expeditions I participated in in 1998 and 1999).
Secondary forests chronosequences are useful but do not fully describe the successional process due to the quite divergent early stages of succession which appear to converge at later stages.
Tree growth rates are greater in lowland evergreen forests than heath forests for larger trees but are actually greater in heath forests for smaller (< 20 cm dbh) trees, probably due to the lower canopy.
- Various funders (starting from sponsors of two undergraduate expeditions I participated in in 1998 and 1999).
Soil microbiology of oil palm plantations
I am currently examining fungal and bacterial populations and enzyme activities in oil palm plantations and determining the comparative resistance and resilience of the respective communities.
- With Dr. Krista McGuire (Barnard College of Columbia University).
Assessing the role of ectomycorrhizal fungi in soil carbon sequestration
Recent funding has been obtained from NERC-NBAF. I will determine changes in ectomycorrhizal fungal abundance and diversity along two altitudinal transects and differing soil depths and hope to combine this with radiocarbon data (in the style of Clemmenson et al in a recent Science paper).
- With Dr. Antony van der Ent (University of Queensland).
- With Dr. Antony van der Ent (University of Queensland).
Ecology of serpentine (ultramafic) plant-soil systems
I have examined the role of serpentine, or ultramafic, soils in influencing plant and fungal distributions, and looked at foliar chemistry of plants on serpentine soils in a number of sites including Malaysia, Jamaica and, much closer to home in Ireland and Scotland.