Plant ecology: succession in plant communities, community responses to disturbance, restoration.

I am a plant ecologist interested in the mechanisms that drive primary plant succession.  Primary succession can be defined as directional changes in plant communities after severe disturbances that leave no soil layers intact. Ecologists have been studying succession for about 100 years but are still in disagreement about what causes it, and even if it exists!  Attempts at general theories that will explain successional change are useful exercises but are not readily applicable to specific examples of succession.  My approach to this dilemma is to examine many examples in different systems, using similar methods, and then to look for similarities or differences between ecosystems.

With my students, I have worked on primary succession on river floodplains and glacial moraines in Iceland and Alaska, dunes in Australia, volcanic substrates in Iceland, Hawaii and New Zealand, landslides in Puerto Rico and New Zealand, abandoned roads in Puerto Rico and Nevada, and mine tailings and reservoir drawdown zones in Nevada.  I examine the effects that species have on the soil and on other plants and how these effects alter succession.  For example, a nitrogen-fixing plant may make the soil favorable for other species, but only after it dies.  My work is typically a mixture of field observations and experiments (such as artificial fertilization, transplanting and sowing of seeds), growth experiments under more controlled greenhouse conditions, and lab analyses of plant and soil nutrients.  My work is therefore at the intersection of plant physiological ecology, community and ecosystem ecology, and soil science with succession as the focal theme.

Other studies that I have conducted include factors that limit rain forest productivity on an elevational gradient and rain forest recovery after a hurricane (both in Puerto Rico), and the demography of bristlecone pines in Nevada.  Locally, I am exploring the causes and consequences of the build up of soil fertility under desert shrubs, experimentally separating out the above and below ground contributions to the increased fertility and the consequences of these “fertile islands” for regeneration of damaged desert communities and for species distributions along elevational ecotones.  My most recent projects have included writing and/or editing four books dealing with disturbance (Ecosystems of Disturbed Ground; Elsevier), succession (Primary Succession and Ecosystem Rehabilitation; Cambridge), restoration (Linking Restoration and Ecological Succession; Springer) and disasters (Environmental Disasters, Natural Recovery and Human Responses; Cambridge).