Significant Research and Accomplishments
Recent research at Pine Lake has focused on five main areas: amphibian ecology, conservation biology, cytogenetics, developmental biology, and invasive species.
The problem of deformed amphibians has been a central environmental issue for over a decade (Sessions and Ruth, 1990; Sessions et al., 1999; Sessions, 2003; Rohr et al., 2009). Professor of Biology Stan Sessions and his students have been investigating the possible causes for deformities and the specific developmental mechanisms involved (Sessions et al., 1999; Stopper et al., 2002). Research has led to the discovery that frogs with extra limbs are caused by parasites, specifically trematodes of the genus Ribeiroia, which use amphibians as a second intermediate host in a complex life cycle. This research was funded, in part, by an NSF collaborative RUI research grant to Stan Sessions (NSF # 0515536 "Collaborative Research: Community Ecology as a Framework for Understanding Disease Dynamics).
Dr. Sessions and his students have also investigated the potential involvement of toxic environmental pollutants on amphibian growth and development, sexual differentiation, and immunology (Houck and Sessions, 2006). Results show that the pesticide atrazine has substantial negative impacts on growth, development, and immune function in anuran tadpoles, and a weak but statistically significant negative impact on sexual differentiation (in favor of females). These results support the idea that atrazine is an endocrine disruptor. Similarly, results show that the gasoline additive MTBE also acts as an endocrine disruptor in frogs (again in favor of females), suggesting that it may interfere with the testosterone biosynthetic pathway (Sessions et al., in prep.).
More recent research has focused on the effects of other environmental stressors, such as crowding and predation, on the incidence of various kinds of deformities featuring missing limbs and limb segments (Ballengée and Sessions, in review). We found that many of these deformities are produced by selective predation by aquatic invertebrate predators, especially dragonfly nymphs which capture and selectively predate the hind limbs or parts of the hind limbs, releasing the tadpoles which may survive through metamorphosis to become adult, deformed frogs.
Species introduced to new locations by human activities are now recognized to be a large and growing ecological problem. In many cases, introduced species have displaced native species or disrupted the normal function of ecosystems. Understanding the effects of introduced species is necessary in order to prevent further losses of biodiversity and changes in ecosystem functions. The main focus of Associate Professor of Biology Mark Kuhlmann’s research in the upper Susquehanna River basin is a non-native species, the rusty crayfish, Orconectes rusticus. Rusty crayfish are native to the Ohio River but have been recently introduced to many rivers and lakes throughout the upper Midwest and Northeastern US and southern Canada.
Most research on introduced populations of rusty crayfish has been done in lakes in Wisconsin, where the species is known to displace and hybridize with native crayfish species, destroy beds of aquatic vegetation, and indirectly alter the composition of lake communities. Much less is known about the effects of introduced rusty crayfish in streams. Research in New York is focusing on 1) documenting the distribution of introduced and native crayfish in the upper Susquehanna River and its tributaries, 2) exploring the mechanisms that allow the rusty crayfish to invade stream habitats, and 3) examining the effects of rusty crayfish on local stream communities. Comparing the mechanisms and effects of O. rusticus’ invasion of streams to previous findings in lakes will provide a broader understanding of the causes and consequences of species introduction.