My main interest is in the distribution and abundance of species over space and time because it is at the heart of the species-environment relationship and thus ecology and it is vital to conservation biology and planning. Understanding species distributions in a causal manner is vital for threatened species management, climate change planning and protected area design. My research combines high-level ecological theory and spatial analysis to address fundamental questions in ecology and to improve tools for applied ecology and conservation biology.

Within the field of species distribution modeling I work on topics such as statistics (especially machine learning techniques), data assembly and management (ecological data sets and remote sensing data), effects of climate and land-use change on species distributions, and spatial patterns and mechanisms underlying species distributions. Population dynamics and dispersal play a prominent role in my investigations of mechanisms underlying distributions. I also use insights and approaches from community ecology to improve the understanding of distributions.

My lab’s research spans from local field experiments to the largest spatial and temporal scales possible (world-wide and hundred thousands of years). Students in my lab and I have worked on plants (e.g. the invasive grass Microstegium vimineum and tree distributions), insects (e.g. ants), birds (hundreds of species in databases, Marbled Murrelets and Pileated Woodpeckers in the field) and fish (Ohio and world-wide data). However, I’m open to work on any organism that promises to advance our insights in ecology and conservation. We often use advanced data management and analysis techniques implemented in R in our research and use advanced technology in the field.

Representative Publications

Bahn, V., B.J. McGill. 2012. Assessing the predictive power of distribution models. Oikos. DOI: 10.1111/j.1600-0706.2012.00299.x

Warren, R.J., V. Bahn. and M.A. Bradford. 2012. Decoupling litter barrier and soil moisture influences on the establishment of an invasive grass. Plant Soil: DOI 10.1007/s11104-012-1477-z

Warren, R.J., V. Bahn. and M.A. Bradford. 2011. The interaction between propagule pressure, habitat suitability and density-dependent reproduction in species invasion. Oikos 121(6): 874–881. DOI: 10.1111/j.1600-0706.2011.20174.x

Warren, R.J., P. McAfee., and V. Bahn. 2011. Ecological differentiation among key plant mutualists from a cryptic ant guild. Insectes Sociaux, 58, 505-512.

Warren, R. J., V. Bahn, and M.A. Bradford. 2011. Temperature cues phenological synchrony in ant-mediated seed dispersal. Global Change Biology 17:2444-2454.

Warren, R.J., V. Bahn, T.D. Kramer, Y. Tang and M.A. Bradford. 2011. Performance and reproduction of an exotic invader across temperate forest gradients. Ecosphere 2:article 14, doi:10.1890/ES10-00181.1.

Burger, A.E., R.A. Ronconi, M.P. Silvergieter, C. Conroy, V. Bahn, I.A. Manley, A. Cober, and D.B. Lank. 2010. Factors affecting the availability of thick epiphyte mats and other potential nest platforms for Marbled Murrelets in British Columbia. Canadian Journal of Forest Research 40:727-746.

Bahn, V. 2008. Failure to find the relationship between dispersal and spatial autocorrelation in species distributions. Journal of Negative Results in Ecology and Evolution 5(1):1-13.

Bahn, V., W. B. Krohn, and R. J. O’Connor. 2008. Dispersal leads to autocorrelation in animal distributions: a simulation model. Ecological Modelling 213(3-4):285-292.

Bahn, V., B. J. McGill. 2007. Can niche-based distribution models outperform spatial interpolation? Global Ecology and Biogeography 16(6):733-742
This paper is featured in a commentary in the Journal of Biogeography by David Currie, the editor of Global Ecology and Biogeography and has been evaluated as “must read” by George Malanson for the Faculty of 1000 Biology.

Bahn, V., R. J. O’Connor, and W. B. Krohn. 2006. Importance of spatial autocorrelation in modeling bird distributions at a continental scale. Ecography 29:835-844.

Bahn V., R. J. O'Connor, and W. B. Krohn. 2006. Effect of dispersal at range edges on the structure of species ranges. Oikos 115:89-96.

Newsom, D. N., V. Bahn, and B. Cashore. 2006. Does forest certification matter? An analysis of operation-level changes required during the SmartWood certification process in the United States. Forest Policy and Economics 9:197-208.

Burger A. E., and V. Bahn. 2004. Inland habitat associations of Marbled Murrelets on southwest Vancouver Island, British Columbia. Journal of Field Ornithology 75(1):53-66.

Bahn V., and D. N. Newsom. 2002. Can Marbled Murrelet use of nesting habitat be predicted from mapped forest characteristics? Pages 89-100 in: Burger A. E., and T. A. Chatwin, editors. Multi-scale studies of populations, distribution and habitat associations of Marbled Murrelets in Clayoquot Sound, British Columbia. Victoria, B.C.: Ministry of Water, Land and Air Protection. ISBN 0-7726-4739-9

Bahn V., and D. N. Newsom. 2002. Habitat suitability mapping for Marbled Murrelets in Clayoquot Sound. Pages 101-119 in: Burger A. E., and T. A. Chatwin, editors. Multi-scale studies of populations, distribution and habitat associations of Marbled Murrelets in Clayoquot Sound, British Columbia. Victoria, B.C.: Ministry of Water, Land and Air Protection. ISBN 0-7726-4739-9

Conroy C. J., V. Bahn, M. S. Rodway, L. Ainsworth, and D. N. Newsom. 2002. Estimating nest densities for Marbled Murrelets in three habitat suitability categories in the Ursus Valley, Clayoquot Sound. Pages 121-137 in: Burger A. E., and T. A. Chatwin, editors. Multi-scale studies of populations, distribution and habitat associations of Marbled Murrelets in Clayoquot Sound, British Columbia. Victoria, B.C.: Ministry of Water, Land and Air Protection. ISBN 0-7726-4739-9

Burger A. E., V. Bahn, and A. R. M. Tillmanns. 2000. Comparison of coastal fringe and interior forests as reserves for Marbled Murrelets on Vancouver Island. Condor 102(4):915-920.