neutral diversity in a metacommunity network
(from Economo & Keitt 2010)
|Biodiversity Dynamics in Spatial
Biodiversity pattern and process manifest on levels of organization and spatiotemporal scales. I'm interested in how ecological and evolutionary processes interact in spatially complex landscapes to drive patterns at different levels of the hierarchy. My work has particularly focused on using network theory to represent the structure of geographic space, where nodes are ecological communities and links represent the movement of individuals among them. Over the last several years I have brought neutral theory into in this framework, investigating how the spatial structure of metacommunities drives diversity patterns. Looking forward, I want to understand how different dimensions of biodiversity, from nucleotides to community interaction webs, vary with isolation in a spatial network. This involves developing new theory but ultimately needs to be addressed empirically. Towards that end my colleagues and I are analyzing the biodiversity of two systems at multiple levels along an isolation gradient in the Pacific. The first system is the ants of the Pacific islands, which I describe below. The second is coral reef fish diversity in marine networks, a collaborative project I am pursuing with colleagues at the Field Museum and in Australia. I am also interested in a broader class of problems related to stochastic processes in biological networks, and have pursued some collaborative work in this area on RNA evolution.
|--Economo, E. P.
Biodiversity Conservation in Metacommunity Networks: Linking
Pattern and Persistence. The
American Naturalist. 177
(6) E167-180. PDF.
--Leibold, M., Economo, E., Peres-Neto, P. (2010) Metacommunity Phylogenetics: Separating the Roles of Environmental Filters and Historical Biogeography. Ecology Letters. 13 (10) 1290-1299. PDF.
--Economo, E. and Keitt, T.H. (2010). Network Isolation and Local Diversity in Neutral Metacommunities. Oikos 119: 1355-1363. PDF.
--Economo, E., and Keitt, T.H. (2008). Species diversity in neutral metacommunities: a network approach. Ecology Letters 11(1): 52‐62. PDF
--Cowperthwaite, M., Economo, E., Harcombe W., Miller, E., Meyers, L. (2008). The Ascent of the Abundant: How mutational networks constrain evolution. PLoS Computational Biology 4(7): e1000110. PDF
Poecilomyrma is Fiji's only endemic ant genus.
New: Timeline of Fiji Ant Research (4.2 MB)
Biogeography of Pacific Island Ants
The Pacific Islands are an amazing island world where thousands of small, isolated terrestrial ecosystems are separated by vast distances. Over millions of years, lineages have dispersed, evolved, and diversified through this network. More recently, humans have introduced a number of exotic species to the islands and these are having dramatic effects on native faunas. These forces combine to assemble the communities of ants we see today on each island. I'm interested in disentangling the processes underlying these patterns with integrative approaches. While ants in this region have been studied for over 100 years, and were the inspiration for E.O. Wilson's seminal work in the development of island biogeography theory, we have found that these island faunas are still remarkably unknown. My colleague, Eli Sarnat, and I have been broadly inventorying ant communities in the Fijian archipelago, and working on a taxonomic reorganization of the fauna. After several years of collecting and curation, our book length monograph detailing and updating the the fauna is now submitted. We are using these data to re-examine Wilson's ideas about the taxon cycle and patterns of community assembly. We also have compiled a thorough dataset on ant distributions across the Pacific, and are analyzing macroecological patterns of the native and invasive species. Looking forward, we are self-organizing with other Pacific myrmecologists to 1) develop and disseminate basic biodiversity data, species lists, etc., 2) use molecular approaches to reveal the evolutionary history of these island lineages and communities, 3) understand how ecological dynamics on a plot scale affect and are affected by biodiversity dynamics on a large scale, and 4) achieve greater synthesis with modeling approaches.
New, Dec 2011! Lacey Knowles, Eli Sarnat, and I have been awarded a grant by the National Science Foundation to develop a regional Indo-Pacific phylogeny for Pheidole and test macroevolutionary and biogeographic theory. The project will start in 2012 and run for 2 years. More soon!
Economo, E. (PI), L. Knowles (co-PI). NSF DEB 1141989. $378,522. "Evolving hyperdiversity in phenotypic, ecological, and geographic networks: testing the taxon cycle and alternatives in Indo-Pacific Pheidole."
Publications and resources:
--Economo, E. P., Sarnat E. M. Revisiting the ants of Melanesia and the taxon cycle: historical and human-mediated invasion of a tropical archipelago. Accepted. The American Naturalist.
--Sarnat, E. M., Economo, E. P. The Ants of Fiji. Accepted. University of California Publications in Entomology. (88,000 word monograph)
--Economo, E.P., Janda, M., Sarnat ,E. M. The island biogeography of native and invasive ant iversity reveals biotic resistance at large but not small scales. In Review.
--Economo, E.P., Blanchard, B.*, Fasi, J., Sarnat, E.M. Checklist of the ants of the Solomon Islands and a new survey of Makira Island. In preparation. * undergraduate co-author
--FijiAnts.org Our website about Fijian Ants and our projects there. (currently being updated, bear with us)
--Fiji Page on Antweb. Antweb is fast becoming the dominant repository for biodiversity info on ants.
-- Eli Sarnat's fantastic Pacific Invasive Ants Key (PIA).
-- Checklist of the myrmecological holdings of the University of Michigan Museum of Zoology (a lot more than we thought, and hardly touched since the 50's).
--Myrmecos blog post about our collecting trip to the Solomon Islands.
from Calder 1984
of Biological Processes
Scaling approaches seek to understand how biological processes change across scales of space and time, and with the basic dimensions of life; the body sizes and temperatures of organisms. My research in this area used metabolic theory to build models on the population and ecosystem scales. This approach was applied to a global dataset of whole ecosystem energy dissipation, as measured by CO2 exchange. Interestingly, the whole ecosystem temperature dependence of energy dissipation was governed by the same mathematical functions as individual organisms, but the parameters changed across geographic space in such a way that the effect of temperature was moderated (Enquist et al. 2003). More recent work integrates life history theory with metabolic theory in order to predict population level rates of energy flow, biomass production, and trophic efficiency (Economo et al. 2005). I began working on this as an undergrad in B. Enquist's lab at U. of Arizona, and although scaling is not currently my research focus, I'm still interested in it.
|Publications:||--Enquist, B.J., Kerkhoff, A.J., Huxman, T.E., and Economo,
E.P. (2007). Adaptive differences in plant physiology and ecosystem
paradoxes: insights from
metabolic scaling theory. Global
13: 591‐609. PDF
--Economo, E.P., Kerkhoff, A.J., Enquist, B.J. (2005) Allometric growth, life history
invariants, and population energetics. Ecology Letters 8: 353‐360. PDF
--Brian J. Enquist, Evan P. Economo, Travis E. Huxman, Andrew P. Allen, Danielle D. Ignace, James
Gillooly. (2003). Scaling metabolism from organisms to ecosystems. Nature 423: 639‐642. PDF
|I am fortunate to have a great group of undergraduate researchers collaborating with me on projects here at the University of Michigan. Several of them are through UROP, which is an excellent program to give freshman a running start as scientists.|
Benjamin is a sophomore UROP student majoring in EEB and working with Evan for a second year. He is interested in a career in Entomology, (specifically Myrmecology), and Biodiversity. This year he is curating and identifying ant specimens from the Solomon Islands, and is collaborating with Evan on a manuscript on the Solomon Island ant fauna. He will also be DNA barcoding each species.
Lizette is a sophomore majoring in Ecology & Evolutionary Biology and is working on an independent study. She is developing biodiversity resources for Pacific ants in a collaboration with the Museum of Zoology. She will also be learning lab techniques and working on ant molecular projects .
Liane is a freshman UROP student working on imaging Pacific ants and organizing information on Michigan ants and the UMMZ collection. She is a Biology major and interested in both Pre-med and Entomology.
Devin is a sophomore UROP student majoring in mathematics and economics. He is working with Scott Page and I on our "Diversity and Complexity in Human Society" project, collecting, organizing, and analyzing datasets on diversity in human society.
Aerial is a freshman UROP student in the Residential College, and is interested in the social sciences. She is working with Scott Page and I on our "Diversity and Complexity in Human Society" project, collecting, organizing, and analyzing datasets on diversity in human society.
Filip is a senior Biology Major here at UM. He is working on an independent study focusing on the allometric scaling of longevity between and within species. He is also working on web design.
Aaron is a sophomore UROP student. He is currently interested in Evolution, especially Human Evolution. He is working on sorting and identifying ant specimens from Fiji and New Guinea, the latter from a recent Conservation International RAP expedition.
Benjamin is a freshman UROP student and an EEB major. Benjamin is interested in a career in Entomology and Biodiversity. He is sorting and identifying ant specimens from Fiji, the Solomon Islands, and New Guinea. He is curating specimens from a recent Conservation International RAP in New Guinea.
Nikhila is a freshman UROP student. A student in the School of Information, Nikhila has been working on compiling a comprehensive database of ant distributions in the Pacific Islands. She is also learning to use GIS tools and will continue to manage and analyze geographic data.