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Tropical Ecology

Head of Group: Dr Edmund Tanner

ed tanner
Tree measuring in Panama.
Our research in tropical forests addresses aspects of biodiversity and global change.

Our most recent work on diversity was done in the Blue Mountains of Jamaica, where we showed that 170 year old secondary forest is almost as diverse as fragments of the remaining natural forest; this is important because it shows that secondary forest can be a significant reservoir of biodiversity.

Our studies of global change are done in Lowland Forest in Panama where we have experimentally increased and decreased litter inputs to large forest plots. We have shown that increased inputs of organic matter - as dead leaves - has resulted in increased soil organic matter, thereby immobilizing some of the extra carbon dioxide in the atmosphere, but it has also increased the decomposition of older soil organic carbon. The production of carbon dioxide from old soil organic matter is potentially a huge source of increased carbon dioxide in the atmosphere and therefore very relevant to climate change.

Current projects include:

Carbon dynamics of tropical forest soils

In lowland rain forest in Panama, where we are adding or removing organic matter, we are modelling the pools and transfers of carbon. This will allow us to assess the effects of varying the inputs of organic matter – such as will occur as a result of increased tree growth due to increased concentrations of carbon dioxide.

Root in tropical forest rain forests

Roots respond to variations in soil fertility. In an experiment in lowland forest in Panama we found that both litter removal and litter addition caused a decrease in root biomass. Predictions, based on well established ‘understanding’ of allocation of resources were wrong for the litter-removal plots. We are revising the model.

Hurricanes effects on Jamaica forest

Using some of the oldest continuously recorded plots in the tropics we are investigating hurricane effects on the dynamics and composition of Jamaican montane forest. The most interesting finding so far is that hurricanes increase growth and increase diversity – both caused by higher light levels lower in the canopy.