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Jesse Bellemare

Assistant Professor

email Send E–mail office Office: Sabin-Reed Hall 248 phone Phone: 585–3812

Jesse Bellemare earned his Ph.D. from Cornell University.

My research focuses on questions in plant ecology, biogeography, and evolution at a variety of spatial and temporal scales. In particular, I am interested in how historical processes, such as past climate change and dispersal limitation, might influence plant species' contemporary distributions and the diversity of plant communities. This line of research is set in the context of foundational concepts in ecology, such as the ecological niche, but also has implications for species conservation in the face of modern climate change. For example, might it be appropriate to consider 'managed relocation' or 'assisted colonization' for dispersal-limited plant species still recovering from past climate change and unlikely to keep pace with anthropogenic climate change? Most of the lab's research is centered in the temperate deciduous forests of the eastern US and we frequently make use of forest herbs, shrubs, and tree species as topics for investigation.

In plant ecology and biogeography, my lab is using a range of techniques to investigate how plant species' distributions at geographic scales might be influenced by climate, soils, ecological interactions, and dispersal limitation. For example, we are using large-scale seed sowing experiments to test how plant species perform within and beyond their natural range boundaries, and under novel climatic and environmental conditions. In parallel, this work has also involved field surveys to examine how natural populations differ in performance and structure from species' range centers to range edges. At equilibrium, ecological models typically predict peak performance near range centers, with declines toward range edges as species reach their ecophysiological limits. However, in at least one species we have investigated in detail (Jeffersonia diphylla), we've found increased performance and population density at the northern range edge, a pattern suggestive of an expanding distribution, rather than one at equilibrium with the environment. Taken together, these sources of information can provide insight into the nature of species' ranges and range edges, helping to decipher whether distribution limits are in close equilibrium with the environment, or potentially lagging behind ancient or recent shifts in climate due to dispersal limitation.

More recently, we have also begun to utilize information from native plant horticulture to explore how frequently and under what conditions plant species can already be found growing outside their native ranges and under novel environmental conditions. Such occurrences have the potential to highlight species' tolerances to climate and environmental conditions, beyond those inferred from the species' native range alone. For some plant species, the mismatch between native range or realized niche, and actual tolerances appears to be quite substantial. To some extent, this line of research views native species' grown outside their native ranges in horticultural as 'accidental experiments' in biogeography. What might be lacking in terms of formal experimental design is counterbalanced by the large numbers of plant species involved in horticulture, the broad extent of horticultural plantings across many regions, and the substantial time frames involved - more than would ever be possible for any individual ecologist or research team. Even more strikingly, many native plant species have been documented to escape and naturalize beyond their natural ranges, providing compelling evidence that these species' native ranges might have been limited by dispersal rather than climatic or other environmental factors. In one striking case, we have documented that the southeastern US native tree Magnolia tripetala is beginning to escape from horticulture and naturalize in western Massachusetts, possibly as a result of recent climate warming in the region.

On a local scale, the lab is also involved in an ongoing study of forest ecosystem ecology and change at Smith College's Ada and Archibald MacLeish Field Station in Whately, MA. At this site we are investigating how forest ecosystems and forest floor animal communities might be changed as a dominant evergreen conifer species, the Eastern Hemlock (Tsuga canadensis) declines due to attack by exotic insects. Research students based in the lab have investigated effects of changing forest canopy conditions on understory bryophyte species, soil organic layer conditions and fungal communities, as well as evidence of ecological interactions between forest floor animals.

Representative Publications

Bellemare, J. and C. Deeg. 2015 - in press. Horticultural escape and naturalization of Magnolia tripetala: Biogeographic context and possible relationship to recent climate change. Rhodora 117: in press.

Bellemare, J. and D.A. Moeller. 2014. "Climate change and forest herbs of temperate deciduous forests." Pp. 460-494 in, F. Gilliam (ed.), The Herbaceous Layer in Forests of Eastern North America, 2nd ed. Oxford University Press, Oxford, UK.

Zukswert, J.M., J. Bellemare, A.L. Rhodes, T. Sweezy, M. Gallogly, S. Acevedo, and R.S. Taylor. 2014. "Forest community structure differs, but not ecosystem processes, 25 years after eastern hemlock removal in an accidental experiment." Southeastern Naturalist 13: 61-87.

Sax, D.F., R. Early, and J. Bellemare. 2013. "Niche syndromes, species extinction risks, and management under climate change." Trends in Ecology and Evolution 28: 517-523

Van der Veken, S., J. Bellemare, K. Verheyen, and M. Hermy. 2007. "Life-history traits are correlated with geographical distribution patterns of western European forest herb species." Journal of Biogeography 34, 1723–35.

Bellemare, J., G. Motzkin, and D. R. Foster. 2005. "Rich mesic forests: edaphic and physiographic drivers of community variation in western Massachusetts." Rhodora 107, 239–283.

Bellemare, J., G. Motzkin, and D. R. Foster. 2002. "Legacies of the agricultural past in the forested present: an assessment of historical land-use effects on rich mesic forests." Journal of Biogeography 29, 1401–20.