Latitudinal gradients of diversity: A taxonomically and geographically comparative perspective
Principal Investigators:
Michael R. WilligThe ubiquity of latitudinal gradients in species diversity has led to a search for biological mechanisms that have universal applicability (i.e., a primary cause). Although over 20 hypotheses have been proposed to account for such gradients (Rohde 1992), recent research suggests that the existence of a gradient, per se, could be the result of stochastic processes (Colwell and Hurtt 1994, Willig and Lyons 1998). Moreover, many of the deterministic hypotheses are circular or unsubstantiated, and all lead to qualitative predictions (i.e.,... more
The ubiquity of latitudinal gradients in species diversity has led to a search for biological mechanisms that have universal applicability (i.e., a primary cause). Although over 20 hypotheses have been proposed to account for such gradients (Rohde 1992), recent research suggests that the existence of a gradient, per se, could be the result of stochastic processes (Colwell and Hurtt 1994, Willig and Lyons 1998). Moreover, many of the deterministic hypotheses are circular or unsubstantiated, and all lead to qualitative predictions (i.e., increases in richness toward the tropics) rather than quantitative predictions about the form of the pattern or the number of species at particular latitudes. As a consequence, much of the supportive data for deterministic hypotheses are indirect and not subject to analyses via strong inference (Platt 1964, Pickett et al. 1994). I propose to conduct research for a 12 month period at NCEAS, during which I will evaluate in a quantitative fashion the predictions of a stochastic model for a variety of taxa (i.e., mammals, birds, reptiles, amphibians, fish) occupying different geographic domains(North America, South America, Africa, Australia, Indo-Pacific Ocean, Atlantic Ocean)
¿ First, I will refine the extant model (Willig and Lyons 1998) to include information about average range size of the taxa of interest, and expand it to two dimensions (latitude and longitude).
¿ Second, I will obtain and digitize data from a variety of sources on the distributions of taxa and incorporate them into a GIS (Geographic Information System).
¿ Third, I will test null models based on gathered data, and convene a working group to explore patterns and search for factors responsible for deviations from the null model.
collapseParticipants and Meetings

Activity | Dates | Further Information |
---|---|---|
Sabbatical Fellow | 2nd September 1998—31st August 1999 | Participant List |
Participant Contact Information
Michael R. Willig | michael.willig@uconn.edu | Texas Tech University |
Products: Publications, Reports, Datasets, Presentations, Visualizations
Type | Products of NCEAS Research |
---|---|
Journal Article | Andelman, Sandy J.; Willig, Michael R. 2002. Alternative configurations of conservation reserves for Paraguayan bats: Considerations of spatial scale. Conservation Biology. Vol: 16. Pages 1352-1363. (Online version) |
Journal Article | Cox, Stephen B.; Willig, Michael R.; Scatena, F. N. 2002. Variation in nutrient characteristics of surface soils from the Luquillo Experimental Forest of Puerto Rico: A multivariate perspective. Plant and Soil. Vol: 247. Pages 189-198. |
Journal Article | Lopez-Gonzalez, Celia; Presley, S. J.; Owen, R. D.; Willig, Michael R. 2001. Taxonomic status of Myotis (Chiroptera : Vespertilionidae) in Paraguay. Journal of Mammalogy. Vol: 82(1). Pages 138-160. |
Journal Article | Lyons, Kathleen; Willig, Michael R. 1999. A hemispheric assessment of scale dependence in latitudinal gradients of species richness. Ecology. Vol: 80. Pages 2483-2491. |
Presentations | Lyons, Kathleen; Willig, Michael R. 1999. Species-area curves and diversity-latitude relationships in the New World. Annual Meeting of the American Society of Mammalogists. Washington. |
Journal Article | Lyons, Kathleen; Willig, Michael R. 2002. Species richness, latitude, and scale-sensitivity. Ecology. Vol: 83. Pages 47-58. |
Presentations | Presley, S. J.; Willig, Michael R.; Owen, R. D. 1999. Species accumulation curves and estimates of species richness: A multisite assessment for bat guilds in Paraguay. Annual Meeting of the American Society of Mammalogists. Washington. |
Journal Article | Sites, Robert W.; Willig, Michael R. 2000. Morphometric variation among populations of Ambrysus mormon Montandon (Heteroptera : Naucoridae). Proceedings of the Entomological Society of Washington. Vol: 102(3). Pages 533-541. |
Journal Article | Stevens, Richard D.; Willig, Michael R. 2000. Community structure, abundance, and morphology. Oikos. Vol: 88. Pages 48-56. |
Journal Article | Stevens, Richard D.; Willig, Michael R. 2000. Density compensation in new world bat communities. Oikos. Vol: 89. Pages 367-377. |
Journal Article | Stevens, Richard D.; Willig, Michael R. 2002. Geographical ecology at the community level: Perspectives on the diversity of New World bats. Ecology. Vol: 83. Pages 545-560. |
Presentations | Willig, Michael R.; Presley, S. J.; Owen, R. D. 1999. Patterns of body size in Paraguayan bats: A hierarchical approach. Annual Meeting of the American Society of Mammalogists. Washington. |
Presentations | Willig, Michael R.; Presley, S. J.; Owen, R. D. 1999. Species-abundance distributions and dominance-diversity relationships in assemblages of Paraguayan bats. Annual Meeting of the American Society of Mammalogists. Washington. |
Journal Article | Willig, Michael R.; Presley, S. J.; Owen, R. D.; Lopez-Gonzalez, Celia. 2000. Composition and structure of bat assemblages in Paraguay: A subtropical-temperate interface. Journal of Mammalogy. Vol: 81(2). Pages 386-401. |
Book Chapter | Willig, Michael R. 2000. Latitude, common trends within. Edited by Levin, S.. Encyclopedia of Biodiversity. Vol: 3. Academic Press. San Diego, CA. Pages 701-714. |
Journal Article | Willig, Michael R. 2001. Exploring biodiversity in time and space: Profitable directions for mammalogy in the 21st Century. Mastozoología Neotropical. Vol: 8(2). Pages 107-109. |
Journal Article | Willig, Michael R.; Kaufman, Dawn; Stevens, Richard D. 2003. Latitudinal gradients of biodiversity: Pattern, process, scale, and synthesis. Annual Review of Ecology Evolution and Systematics. Vol: 34. Pages 273-309. (Abstract) |
Book Chapter | Willig, Michael R.; Patterson, Bruce D.; Stevens, Richard D. 2003. Patterns of range size, richness, and body size in the Chiroptera. Edited by Kunz, Thomas H.; Fenton, Brock M. Bat Ecology. The University of Chicago Press. Chicago. Pages 580-621. |