Summer seminar: The Value of Long-term Experiments in Ecology: The Kansas Habitat Fragmentation Experiment, 40 years old and counting

This ad-hoc seminar open to all members of the University of Cambridge is organised by Professor Rob Fletcher.  Please contact Rob (rf497@cam.ac.uk) if you would like to meet with Professor Holt after his lecture or for dinner.

Speaker: Professor Robert D. Holt, Eminent Scholar in Biology, Arthur R. Marshall, Jr., Chair in Ecological Studies, The University of Florida

Abstract: Habitat degradation and fragmentation, along with climate change, are primary drivers of the biodiversity crisis.  Like any theme in science, habitat fragmentation can be studied with observational and comparative empirical analyses, theory and modelling, and experimentation. For the former two, there are many thousands of studies and publications, but there are just a handful of experimental studies of fragmentation (for understandable practical and logistical reasons). One such study was initiated in the prairie-forest of eastern Kansas in 1984, and is still running today (it is one of the longest experiments in ecology). 

This talk will start with reflections on the intellectual groundings and personal background explaining the origin of the project.  Why did a theoretical ecologist like myself improbably set up a huge field experiment like this? Unlike most such experiments, the focus is on how fragmentation influences the rate and pattern of ecological succession from an old field to woodland (so it is more relevant to restoration ecology, than to conservation).  

I will explain the overall design of the project, and sketch some key results for dynamics in plant and small mammal communities.  A predicted effect of patch size and distance to sources on succession took a decade and more to be manifest -- illustrating the general issue of the importance of long transients in ecological systems.  The experiment demonstrates a complex interplay of landscape structure and succession in generating observed spatial patterns in communities.  

I will also touch on how this experiment helped motivate spin-off developments in theoretical ecology, ranging from source-sink dynamics, to metapopulation and metacommunity ecology, to the interplay of spatial processes and trophic interactions in food webs.