Keesing's research focuses on the consequences of human impacts, particularly
biodiversity loss, for ecological communities. In
Kenya, she has studied how the experimental absence of large
mammals like
giraffes and
elephants affects savanna ecology, in particular the rodent community. She and
Richard Ostfeld pioneered research on the ecology of
Lyme disease, in particular how human risk for Lyme disease is affected by
forest fragmentation and the loss of
biodiversity. She and Ostfeld also developed core ideas about the general relationship between biodiversity loss and the emergence and transmission of
infectious diseases, and a conceptual model of the effects of pulsed resources on ecological communities. From 2016 to 2021, she and Ostfeld co-directed the Tick Project, a study to test whether environmental interventions could prevent Lyme and other
tick-borne diseases in residential neighborhoods of
Dutchess County, New York. Keesing's recent research in Kenya focuses on the ecological, economic, and social consequences of managing land in
Laikipia County, Kenya for
livestock,
wildlife, or both. In 2009, she served on the steering committee for the Vision and Change initiative to reform the teaching of undergraduate biology, and from 2012 to 2017, with funding from the
Howard Hughes Medical Institute, she directed a project on
science literacy for college students. In 2017, she led the development of the curriculum for the Citizen Science program at Bard College. Through grants offered to Keesing from the National Geographic Society, the National Science Foundation, and the National Institutes of Health, she has published over 100 different papers. Her work has also been reported on by various news sources, such as but not limited to, the New York Times, The New Yorker, NPR, and the Guardian. ==Awards and recognition==