Population ecology of pond turtles & herpetofaunal survey on the Benedictine University Lisle Campus
In Summer 2018 The Harden Lab established a long-term monitoring program to document vertebrate wildlife inhabiting the Benedictine University campus. The natural and man-made ponds and lakes on campus are home to several reptile and amphibian species (based on visual encounter surveys), but it is largely unknown the population demographics, health and survivorship, and general ecology of these species, in addition to their how they utilize their suburban environment (on and off campus). A herpetofaunal inventory on campus will primarily include an assessment the population ecology of aquatic pond turtles in the natural and man-made pond on campus via aquatic trapping and spatial capture-mark-recapture robust sampling approach, and will also include an assessment of other herpetofaunal diversity via opportunistic hand captures, dip-netting, minnow traps, and aural surveys. This research aims to provide students with the opportunity to formulate basic questions about reptile and amphibian biology and participate in simple observational studies to answer questions. Furthermore this research project will educate and raise awareness of the herpetofaunal species on campus.
Evaluating the health and physiology of threatened Blanding’s turtles
The Harden Lab and the Milanovich Lab are conducting research on the physiological health of captive-reared hatchling and juvenile endangered Blanding’s turtles at captive-rearing programs in the Midwest. This research on the physiology and stress levels of Blanding’s will contribute to the gap in knowledge concerning the effects of captive-rearing efforts on their health and survival and allow for better recommendations regarding captive-rearing procedures. The Harden Lab also investigated Hg levels in gravid female Blanding’s using claw tissue (Publication 1). We are currently collaborating with and educating regional stakeholders on potential long-term impacts of head-starting and translocation programs. Read about the Harden Lab in the Benedictine University’s Spring 2017 magazine Voices, The Daily Herald: Blanding’s turtles get a boost in DuPage, or NCTV17: Forest Preserve Releases Endangered Turtles.
Examining the ecology and physiology of Ornate box turtles in northern Illinois
With funding from the Illinois Department of Natural Resources, the Harden Lab is collaborating with the Milanovich Lab @ LUC to examine the characteristics of hibernaculum (Publication 1), home range sizes, blood chemistry (Publication 2), and stable isotopes of ornate box turtles (Terrapene ornata) at three sites in northern Illinois. This work involves several undergraduates and graduate students at LUC.
Physiological ecology of diamondback terrapins
In Collaboration with Dr. Amanda Southwood Williard, Dr. Harden is investigating the behavioral and physiological mechanisms that allow diamondback terrapins (Malaclemys terrapin) to inhabit a dynamic coastal ecosystem. These studies have provided insight into the terrapin’s ability to maintain osmotic homeostasis while experiencing shifts in behavioral and environmental conditions. Further, they shed light on the relative importance of behavioral and physiological adjustments that may have served as pivotal evolutionary steps in the freshwater chelonian invasion of marine environments (Publication 1, Publication 2, Publication 3). Laboratory-controlled osmoregulation and energy metabolism studies of terrapins are ongoing with colleagues Amanda Southwood Williard @ UNCW and Dr. Stephen Midway @ LSU. (photo credit: Jackie Guzy).
Spatial and temporal overlap of terrapins and the blue crab fishery
In Collaboration with Dr. Amanda Southwood Williard, Dr. Harden investigated the seasonal changes in diamondback terrapin activity and habitat use as it related to potential spatial and temporal overlap with the blue crab fishery – a source of terrapin bycatch and subsequent population declines along the US coast. To assess spatial overlap and resulting bycatch risk (BR), seasonal distributions and densities of crab pots and terrapins were calculated and incorporated into a spatial overlap index model modified to include the seasonal aquatic behavior of terrapins. This behaviorally modified model may be applied to other geographic areas to identify areas and times of bycatch risk between fisheries and non-target species (Publication 1). Check out this Coastwatch article: Mapping the Overlap: Terrapins & Crab Pots in the Lower Cape Fear Region, this North Carolina Coastal Federation article: Looking for Answers to Help Terrapins, or this 2013 StarNews newspaper article: Diamondback terrapins subject of UNCW student’s research.
Population and reproductive biology of spotted salamanders
Dr. Harden and Dr. Shannon Pittman coordinated several research projects with Davidson undergraduates on spotted salamanders at an isolated wildlife refuge wetland. We investigated various topics such as 1) the development and evaluation of individual identification methods for spotted salamanders (Publication 1), and 2) the influence of sex and migration behavior on reproduction cost of spotted salamanders (Publication 2).
Mud turtle habitat selection in a modified landscape
At Davidson College Dr. Harden conducted a radio-telemetry study of semi-aquatic eastern mud turtles inhabiting a golf course pond to investigate their terrestrial activity and habitat selection (Publication 1), and thermal ecology (Publication 2). Information from this study allows for a better understanding of critical upland habitat requirements of other semi-aquatic species and can aid in developing golf course land management plans. Check out the Charlotte Observer article about this turtle research on a golf course.