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David K. Skelly
Yale University
School of Forestry & Environmental Studies
370 Prospect Street
New Haven, CT 06511 USA

Yale FES



Lily Twining

Lab: Osbourne Memorial Laboratory, Room 426

B.A. Environmental Studies
Yale University
M.E.Sc. Forestry & Envir. Studies
Yale University

I am generally interested in questions that combine aspects of community, landscape, and ecosystem ecology and have a historical component.  Specifically, I am interested in nutrient transport by migratory fishes and the effect of land use change on freshwater systems.  Migratory fishes and human activities, such as agriculture and septic tank use, can both be major sources of nutrient that drive primary production and ecosystem function in freshwater systems.  However, over time these two sources of nutrient inputs have gone in opposite directions: at the same time that migratory fish populations have declined, human land use has intensified.  I am interested in understanding when migratory fishes are or were an important source of nutrients and how that varies based on migratory fish life history traits, regional climate and geomorphology, and regional land use history.

Undergraduate Research
In my undergraduate senior thesis in David Post's (Yale E&EB) lab, I explored the ecological history of two watersheds in south central Connecticut from pre-colonial times to present, with a particular emphasis on the history of alewife (Alosa pseudoharengus), an important keystone fish species in the region.  I examined this question from both an environmental history approach, in which I searched for records of milldam construction and fish stocking in my study watersheds, as well as a paleoecological approach, in which I cored several lakes and studied zooplankton remains to reconstruct lake community structure and nitrogen stable isotopes to reconstruct past sources of nutrient loading.  My research suggested that several populations of landlocked, non-migratory alewife in the region likely became landlocked due to colonial dam construction and that prior to that all lakes with connections to the ocean without natural barriers (waterfalls or beaver dams) would have supported runs of anadromous alewife.  I also found that humans began to have a noticeable impact on the nutrient cycles of south central Connecticut's freshwater systems soon after the arrival of Euro-American settlers in the region 300-400 years ago.

Master's Research
Dave Skelly and David Post (Yale E&EB) are co-advising me in my master's through the Yale College-Yale F&ES 5th Year Program.  In my master's research, I am expanding upon my undergraduate thesis work to ask how nutrient loading from anadromous fishes and non-anthropogenic sources in coastal Connecticut has historically compared to nutrient loading from anthropogenic sources and how different these sources of nutrients have affected lake primary production over time.  I am then using this information to model potential future nutrient loads and primary production in the region's lakes with both restored runs of alewife and other anadromous fishes and continued intensive human land use.

Supply Ponds fish ladder, April 2011.



Twining, C.W. and D.M. Post. (in prep) Cladoceran remains reveal presence of keystone size-selective planktivore. To be submitted to Journal of Paleolimnology.

Twining, C.W. (in prep) Changes in the lakes: the ecological history of freshwaters in coastal Connecticut. To be submitted to Environmental History.


Twining, C.W. April 2011. The ecological history of two watersheds in south central Connecticut. Pierson College Mellon Senior Thesis Research Forum, Yale University, New Haven, Connecticut.

Twining, C.W. April 2011. The ecological history of two watersheds in south central Connecticut. Yale Environmental Studies Program Senior Thesis Presentation, Yale University, New Haven, Connecticut.

Twining, C.W. May 2011. Alewives and Rogers Lake; what ecological history tells us. Old Lyme Land Trust and Old Lyme Town Conservation Commission presentation, Old Lyme, Connecticut.

Twining, C.W. May 2011. Alewives and Linsley Pond: what ecological history tells us. Linsley Lake Association presentation, North Branford, Connecticut.

Twining, C.W. May 2011. The ecological history of the Linsley Pond-Queach Brook watershed. Branford Land Trust annual meeting, invited speaker, Branford, Connecticut.

Twining, C.W. June 2011. Alewives and Rogers Lake: what ecological history tells us. Rogers Lake Authority presentation, Old Lyme, CT.