A Great Blue Heron strides through high tide. A coyote on the hunt trots in the dark of the night. A Green Heron stands poised amidst the wetland vegetation. These are but a few of the scenes observed this past year during a field experiment. Dr. Kenneth Raposa, the reserve’s Research Coordinator, and I, Alaina Bisson, the reserve’s 2019 Seasonal Research Assistant, developed a project examining how wildlife use salt marshes undergoing thin-layer sediment placement (TLP). TLP is a strategy involving the placement of sediment or dredged material on top of a marsh to simulate the accumulation of sediment and organic material that naturally occurs in salt marshes. TLP rapidly increases the elevation of salt marshes allowing them to withstand accelerated rates of sea-level rise.
Two salt marshes in Charlestown, RI underwent TLP: Quonochontaug (Quonnie) marsh and Ninigret marsh. Quonnie marsh had dredge material applied from December 2018 to January 2019 and Ninigret marsh had dredge material applied from December 2016 to January 2017. Quonnie marsh is considered an “early stage TLP” site when compared to Ninigret marsh, a “late stage TLP” site. At both marshes, areas where no sediment was applied are considered “control marsh.” We questioned whether wildlife would use these distinctive TLP and control marsh areas differently. In an attempt to answer this question, we set up a total of 9 motion-sensor wildlife cameras across all sites: early stage TLP in Quonnie marsh, late stage TLP Ninigret marsh, and control marsh in both. We set up the cameras in July 2019 and collected photos and videos until November 2019. Once the cameras were collected from the field, the fun began! Hundreds of hours and thousands of photos and videos later, a total of 40 species were observed across all sites. Among the most abundant species were Tree Swallow, Eastern Cottontail, European Starling, White-tailed Deer, Great Egret, and Coyote. More wading and shore birds were observed in control marsh areas, while mammals dominated both early and late stage TLP areas.
We expected the cameras to have captured a number of informative photos and videos during their deployment, but in fact, the quality of said photos far surpassed our expectations! The images captured gave us an up close look at many species, particularly those that often evade human observation, like the American Bittern, or are nocturnal, such as the Yellow-crowned Night Heron and opossum. So take a look for yourself, and virtually immerse yourself in the salt marshes of Charlestown, RI! Check out some of the many interesting snapshots and video clips captured of wildlife in action.