Climatic Change and Spatial Patterns of Diversity

I am working on several projects that use models, historical ecology and experiments to understand the effects of actual and predicted climate change on ant species and ecosystems. First, in collaboration with Nate Sanders (Tennessee) and Rob Dunn (NCSU), I am re-sampling site where ants were collected more than 50 years ago to try to understand how recorded climate change has affected ant assemblages. Second, with Dunn, Sanders and Matt Fitzpatrick (Harvard Forest), I am developing predictive models of how current species ranges and patterns of diversity should change under expected climate change. Lastly, with Dunn, Sanders, Nick Gotelli (Vermont) and Aaron Ellison (Harvard), I am working on a project that will experimentally warm large plots in Duke Forest and Harvard Forest and examine how ant assemblages and ecosystem function change with increasing temperature. click here for the project webpage

Latitudinal Gradients of Species Diversity

I am interesting in developing process based explanations of diversity gradients, especially latitudinal diversity gradients. See:

• Weiser et al. 2007.Latitudinal patterns of range size and species richness of New World woody plants. Global Ecology and Biogeography 16(5): 679-688.
• Weiser in prep. Latitudinal patterns of range size and species diversity of New World mammals.
• Weiser. in prep. Is there a general explanation for the latitudinal gradient in species diversity of New World mammals?
• Weiser and Swenson, in prep. Spatial patterns of phylogenetic and taxonomic diversity metrics in New World mammals

Latitudinal Gradients of Range Size

Numerous explanations for diversity gradients explicitly incorporate predictions or assumptions about gradients of range size (e.g., Rapoport's Rule, The Mid-Domain Effect). In many cases, our knowledge about the distributions of range sizes is limited. My work focuses on better understanding of the distributions of range size across both space (e.g., latitudinal gradients) and taxa (e.g., range-size frequency distributions). See:

• Weiser et al. 2007.Latitudinal patterns of range size and species richness of New World woody plants. Global Ecology and Biogeography 16(5): 679-688.
• Weiser. in prep. Latitudinal patterns of range size and species diversity of New World mammals.

Diversity Theory

I am interested in theory that offers multi-scale predictions of patterns of diversity. I am specifically interested in recent hypotheses that are "null" relative to more traditional explanations for diversity patterns, such as neutral models and geometric constraint models. See:

• Weiser in prep. Non-biological gradients in species diversity and a spurious mid-domain effect.
• McGill, B., B. Maurer, and M.D. Weiser. 2006. Empirical evaluation of neutral theory. Ecology 87(6):1411-1423
• Enquist, B. J., J. Sanderson, and M.D. Weiser. 2002. Modeling macroscopic patterns in ecology. Science 295:5561-2.

Morphological and Functional Trait Diversity

While much of my work focuses on taxonomic diversity, the "real" pattern of diversity is the spatial and phylogenetic distribution of the traits of organisms. See:

• Weiser and Swenson, in prep. List-weighted and abundance-weighted trait distributions in North American trees.
• Kaspari and Weiser 2007. The size-grain hypothesis: do macroarthropods see a fractal world? Ecological Entomology 32:279-282.
• Weiser and Kaspari 2006. Ecological morphospace of New World ants. Ecological Entomology 31:131-142.
• Kaspari and Weiser 1999. Interspecific scaling in ants: the size grain hypothesis. Functional Ecology 13(4):530-538.

Island Biogeography

See:

• Triantis, K.A., M. Mylonas, M. D. Weiser, K. Lika, and K. Vardinoyannis. 2005 Species richness, environmental heterogeneity and area: A case study based on land snails in Skyros archipelago (Aegean Sea, Greece). Journal of Biogeography
• Lomolino, M. V. and M.D. Weiser. 2001. Towards a more general species-area relationship: diversity on all islands, great and small. Journal of Biogeography 28(4) 431-445.