Studying Ecological Soundscapes of Restored Salt Marshes in Delaware Bay
2023 Q1 Wildlife Acoustics Grant Program Winner
Awarded: 6 Song Meter Minis, Recorder Accessories, and 1 Kaleidoscope Pro License
Where will your research project take place?
Our project will take place within the Delaware Estuary—a 6,800-square-mile tidal system in the mid-Atlantic United States dominated by salt marshes. Acoustic recording units (ARUs) will be deployed at four sites on the New Jersey side of Delaware Bay that are flagged for future habitat restoration.
This sensitive area is home to roughly 60 Endangered Species Act-listed or locally at-risk species, including the largest breeding populations of saltmarsh sparrow (Ammodramus caudacutus) in the Northeastern US, and the Eastern black rail (Laterallus jamaicensis), which is listed as Threatened.
What questions are you attempting to answer?
Unfortunately, salt marsh habitat is declining locally and globally due to sea-level rise. We are interested in understanding if and how a salt marsh soundscape changes as a result of restoration activities. (This work was impossible before bioacoustic technology, so it is a new and exciting field of study!)
Because our team has not used acoustics as a survey tool for restoration projects, our project will be a proof-of-concept. Through our research, we hope to answer the following questions:
- How do tidal marsh soundscapes change after restoration and in response to different restoration treatments? Are they more or less acoustically complex?
- What are the differences in habitat function before and after restoration?
- Can we hear a difference between the soundscapes of rural and urban marshes? Is there a difference in anthropogenic disturbance? How do indicator species respond to these disturbances?
- If present, how does listed species' presence rate differ after restoration?
How will you use bioacoustics to meet your objectives?
We’ll deploy Song Meter Minis for one full breeding season before restoration begins, allowing us to record and compare soundscape complexity and presence/absence of indicator species before and after restoration. Using passive acoustic monitoring, we’ll be able to gather large amounts of data without much in-field manpower and detect cryptic species, including king rails (Rallus elegans), clapper rails (Rallus crepitans), and American bitterns (Botaurus lentiginosus).
For soundscape analysis, we’ll perform cluster analysis and assign four-letter codes to all abiotic and biotic sounds with varying levels of specificity. After data is coded, we will likely use long-term spectral averages (LTSAs) to determine temporal changes in noise. Our intended analytical approaches will be the Before-After Control-Impact (BACI) analysis, correlation tests, and Analysis of Variance (ANOVA).
How will your project impact or expand wildlife conservation or research?
Acquiring this data to understand how tidal salt marsh species respond to intervention activities will be invaluable to restoration ecology. We want to ensure that these multi-goal restoration projects have desired positive impacts on wildlife habitat, and we intend to share lessons learned with other monitoring and restoration workgroups. Because publications investigating the acoustic niche hypothesis in salt marsh habitats do not exist, the results of our work could identify data gaps and inform other acoustic research projects.
Will you collaborate with anyone else?
PDE and partners are already designing and implementing salt marsh restoration projects to protect these highly productive, carbon-sequestering ecosystems. These data will be part of ongoing Delaware Bay restoration projects with our partners at the US Fish and Wildlife Service, Ducks Unlimited, and Conserve Wildlife Foundation of NJ, among others. This ongoing plan includes traditional point count and call-back surveys for salt marsh birds at our sites.
About primary researcher Kelly Faller, BSc
Kelly Faller is a graduate of the Department of Ecology, Evolution, and Natural Resources at Rutgers University, where she focused on wildlife management and conservation. For her honors thesis, she used passive acoustic monitoring to collect bat call data to determine relative foraging rates and habitat use across sites of varying levels of invasive understory vegetation. Kelly has worked with several government agencies and NGOs in a conservation capacity. Today, Kelly is an Estuary Science Specialist at the Partnership for the Delaware Estuary, where she applies her expertise in acoustic ecology to promote the health of the Delaware Estuary.
About the Partnership for the Delaware Estuary
The Partnership for the Delaware Estuary (PDE) is an environmental nonprofit organization dedicated to protecting the Delaware Estuary. The Delaware Estuary supplies clean drinking water for millions of people, supports a booming industrial region, and provides open-access outdoor recreation. PDE collaborates with governments, nonprofits, corporations, and citizens to restore the vital waters that nourish our communities. PDE leads science-based efforts to prevent pollution, protect wetlands, and restore mussels and oysters, and fosters community engagement through workshops, river cleanups, and other special events.
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