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Associate Professor of Zoology
President’s Associates Presidential ProfessorPhone: (405)325-3371
Fax: (405)325-6202RM/Lab:SH202
Dr. Kaspari's Web Page
Current Research Interests and Subject Areas Available for Graduate Research
Ecologists study the factors that regulate the abundance and diversity of organisms. We explore how ants and other soil invertebrates vary in abundance and diversity as we move from place to place across the planet. Sometimes that means comparing the makeup of the arthropod community a few meters away, other times it requires us to catch a flight to Panama, Oregon, or Massachusetts.
Abundance
Many terrestrial organisms vary in density 10-100 fold at small spatial scales (along a 300 m transect) and large spatial scales (from tundra to rainforest). A big part of understanding abundance patterns in ectotherms is understanding how energy is captured and conserved. Also, every evolutionary group, or taxon, has properties which govern its abundance--these properties vary systematically with its age.Organisms often reach their peak abundance in tropical rainforests. Much of our work takes place in on Barro Colorado Island, where I have studied the ant communities since 1990. The ant communities on BCI may contain over 400 species, and the species that interact in the forest canopy are distinct and different from those that forage in the litter 20 m below. The litter ants interact in a rich community of invertebrates, bacteria and fungi, that make their living decomposing the leaves, branches and fruits that fall from the forest canopy, in what we call the brown food web . Most of our lab's field work is exploring the links in these interactions, in particular, how 1) soils, trees, and other animals create nutrient patches that limit the number of trophic levels, 2) species of trees generate leaves with different physical and chemical properties (some are tasty, some are rich with Calcium, some are protected with tannins) that select for different decomposer microbes, and support different numbers of decomposers, and 3) army ants roam the litter, preying on different species of ants and soil invertebrates, and with potentially huge impacts on the brown food web.
Diversity
The number of species, the shape, even the color of taxa varies systematically as you move from place to place across our planet. Perhaps the "holy grail" of ecology is to understand the causes of these biodiversity gradients. Toward understanding the patterns of biodiversity and their causes, we have studied 49 ant communities from the New World, roaming from tundra and warm deserts to lowland tropical rainforests. The answer to the question "what regulates biodiversity" turns out to be scale-specific. At small spatial scales it is driven by patterns of abundance at and, as the measurement plot grows larger, factors that promote speciation play a more important role. A 100-site data set from Phil Ward at the University of California-Davis, shows that these rules generalize across 4 different biogeographic provinces.Brown food webs are biodiversity hotspots found everywhere on the planet. Their key taxa, including fungi, collembola, mites, and spiders are also among the world's most poorly known taxa. A key goal of the AntLab is to build on our growing ant data base on BCI, and to collect and identify taxa from these superabundant yet understudied organisms. Toward that end, we are exploring if and how tropical trees produce litter templates that organize this diversity.
Behavior and Life History
To an ecologist, the behavior and life history decisions of individuals provides the mechanism for interactions among species. The foraging behavior of a complex assemblage of species represents a rhythm manifest at daily and seasonal time scales and the decision when to reproduce is constrained, not only by weather, but by phylogeny. Both have profound implications for the maintenance of diversity. Finally, in colonial insects, body size reflects the magnitude and covariance of two life history traits: the number of workers and their individual size. In an ongoing project titled "Beyond Bergmann's Rule", we are exploring how life history theories predict this size variation on a global scale, and the implication for the structure of communities.
To learn more about this research, visit Dr. Kaspari's web page.
M.S., University of Nebraska
B.S., University of Nebraska
Selected publications:
Kaspari M, M Yuan, L Alonso. (2003) Spatial grain and gradients of ant species richness. American Naturalist: 161, 459-477.
Kaspari M, T Valone. (2002) Seasonal resource availability and the abundance of ectotherms. Ecology.83: 2991-2996
Kaspari M, J Longino, J Pickering, D Windsor. (2001) The phenology of a Neotropical ant assemblage evidence for continuous and overlapping reproduction. Behavioral Ecology and Sociobiology. 50 (2001) 4, 382-390.
Yanoviak, S and M Kaspari (2000) Community structure and the habitat templet: ants in the tropical forest canopy and litter. Oikos 89:259-266.
Kaspari M, S O Donnell and JR Kercher (2000) Energy, density, and constraints to species richness: studies of ant assemblages along a productivity gradient. American Naturalist 155:280-293
Kaspari M, S. O'Donnell, and L Alonso (2000) Three energy variables predict ant abundance at a geographic scale. Proceedings of the Royal Society B 267:485-490.
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