Takehiko Yamanaka will talk on
Environmental condition vs. Spatial constraint? Dragonfly metapopulation and metacommunity analyses
at 12:30 in the EEB lounge (BioSciences 4338)
Populations and communities in nature are largely affected by the within habitat environments, by land use around ponds and by spatial constraint. However, it is generally difficult to disentangle how each affects populations and communities. To evaluate the relative importance of these factors in a damselfly (Copera annulata) metapopulation and an odonate (Zygoptera and Anisoptera) metacommunity living in 74 ponds in Japan, we employed a novel method, variation partitioning, developed in community ecology. The variation partitioning technique evaluates both the relative and the joint contribution of a factor to the total explanatory power of the population and the community model.
As a result from the analysis of the C. annulata, a single species population, we found that spatial autocorrelation had the largest effect and it explains almost all of the variation including both connectivity among ponds and the variation explained by within patch quality. This result shows us that the importance of spatial autocorrelation may not always be interpreted as a spatial constraint limited by the dispersal ability of an organism. For the community analysis, we found that spatial autocorrelation was the most important, though the within-habitat environment and land use had comparable effects. I will discuss how these results can be applicable in conservation practices.
Takehiko Yamanaka is a senior researcher at the National Institute for Agro-Environmental Sciences in Tsukuba, Japan. He is an entomologist and has worked with beetles, true bugs, dragonflies and moths. Takehiko has worked closely with applied entomology to understand the causes of insect-pest outbreaks in natural populations. Recently (Aug 2013), working with Bill Nelson and Ottar Bjørnstad, Takehiko co-authored a paper in Science that linked environmental temperature with outbreaks of the smaller tea torix moth, a pest species of tea plantation in Japan.
Everyone is welcome to attend
Coffee and treats available at the seminar