NCEAS Project 2085

Latitudinal gradients of diversity: A taxonomically and geographically comparative perspective

  • Michael R. Willig


ActivityDatesFurther Information
Sabbatical Fellow2nd September 1998—31st August 1999Participant List  

Abstract

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.

TypeProducts 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.
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.