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Alumni in the News: Dr. Ophelia Wang in Science Magazine

Why Tropical Trees are Rare...and Common

Posted: October 22, 2013
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Alumna Dr. Ophelia Wang's research in the Amazon Basin has helped contribute to some surprising findings published in the recent issue of Science magazine. The article changes how tropical rain forests are thought to function, as Hans ter Steege and coauthors reported on the discovery of “hyperdominance” in the Amazon, with only 227 tree species found to represent almost half of all individual trees growing in the basin. The researchers also conclude that there are about 16,000 tree species in the Amazon basin, based on extrapolations from tree identity and size data on 1170 one hectare tree plots.

Three of those one hectare plots were established by Dr. Ophelia Wang, a 2011 Ph.D. graduate from the Department of Geography and the Environment, as part of her doctoral research. Along with her advisor, Dr. Kenneth Young, Dr. Wang chose three places to sample in remote places in the Ecuadorian Amazon. These sites are on lands controlled by indigenous peoples, specifically the Achuar, Shiwiar, and Zapara people; access was possible through a large conservation and research project run by Dr. Rodrigo Sierra, with crucial field help from Ecuadorian botanist Milton Tirado. All four are among the coauthors in the article.

The fieldwork entailed mapping with local assistants the locations and sizes of all trees with at least 10 cm diameters. Sometimes the trees could be identified from bark, but usually the leaves needed to be clipped with long poles or reached by climbing. The trunks were marked with numbered tags so that the trees can be relocated and their growth measured in the future.  As an example, one plot sampled by Ophelia contained 622 individual trees from 279 species, meaning that almost every other tree on the plot was from a different species; these are hyperdiverse forests, with many rare species. However, it was only when hundreds of such inventory plots, done by 120 researchers from 88 different institutions, were recently combined into one massive database that they realized that only a couple hundred species were dominants across the entire Amazon. This discovery dramatically changes how these forests will be studied, with many ecosystem and conservation properties likely controlled by those relatively few dominant species.  This study is an example of how “big science” can be done by groups of collaborating ecologists, botanists, and biogeographers to produce findings that no individual researcher could have discovered.

Dr. Wang's dissertation included detailed analyses of the three forest plots in Ecuador, plus further testing of remote sensing approaches for measuring forest canopy heterogeneity. She also did a conservation assessment using landscape zonation on the indigenous lands. After her graduation from the UT Department of Geography and the Environment, she became a research associate at Northern Arizona University where she has worked on research projects that developed spatial models of non-native plant invasion, fire risk, and wildlife habitat to support conservation in the arid Southwest. She also joined a collaborative project in the La Mosquitia region of Honduras to link multi-temporal remote sensing data with socio-economic data to provide evidence on deforestation. Currently she is also working in Jakarta, Indonesia, where she is completing an internship on the Indonesian Forest and Climate Support project funded by USAID Indonesia, which will prepare landscape conservation plans. She plans to study the language and work further in the Asian tropics.

Science Magazine (Science, 18 October 2013: Vol. 342 no. 6156, DOI: 10.1126/science.1243092)

Figures:

Ophelia, botanists, and local guide from the Sawastian community in the Ecuadorian Amazon.

Details of tree sizes and locations being mapped and measured by Ophelia Wang and colleagues.

Amazon rain forest in Achuar lands in Ecuador.

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