Research
DISSERTATION RESEARCH: Investigating ontogenetic shifts in movement and behavior in highly mobile marine predator Carcharodon carcharias
In my dissertation, I am working to synthesize animal-borne sensors with remote sensing data to define the demographic composition, dynamics, and behavior of the juvenile white shark populations utilizing Monterey Bay National Marine Sanctuary waters. I will use long-term adult monitoring sites as a comparative aggregation through which to understand ontogenetic partitioning, overlap, and recruitment of younger members of the species.
Specifically, I am utilizing underwater imaging and aerial observation via Unoccupied Aircraft Systems (UAS) to quantify white shark swimming kinematics and morphometrics across demographics, combining underwater imaging with electronic tags to characterize demographic structure across sites, and evaluate thermal and vertical habitats. This dissertation proposal works to define and compare ontogenetic aggregations in MBNMS waters, adding critical knowledge of ontogenetic progression and recruitment in a marine apex predator population.
Considerations and tradeoffs of UAS-based coastal wetland monitoring in the Southeastern United States
Coastal wetlands of the Southeastern United States host a high abundance and diversity of critical species and provide essential ecosystem services. A rise in threats to these vulnerable habitats has led to an increased focus on research and monitoring in these areas, which is traditionally performed using manual measurements of vegetative characteristics. As these methods require substantial time and effort, they are often limited in scale and infeasible in areas of dense or impassable habitat. Unoccupied Aircraft Systems (UAS) provide an advantage over traditional ground-based methods by serving as a non-invasive alternative that expands the scale at which we can understand these ecosystems. While recent interest in UAS-based monitoring of coastal wetland habitats has grown, methods and parameters for UAS-based mapping lack standardization. This study addresses variability introduced by common UAS study techniques and forms recommendations for optimal survey designs in vegetated coastal habitats. Applying these parameters, we assess alignment of computed estimations with manually collected measurements by comparing UAS-SfM mapping products to ground-based data. This study demonstrates that, with careful consideration in study design and analysis, there exists great potential for UAS to provide accurate, large-scale estimates of common vegetative characteristics in coastal salt marshes.
https://www.frontiersin.org/articles/10.3389/frsen.2022.924969/full
Coastal shark abundance and spatial dynamics respond to small-scale environmental fluctuations of the Rachel Carson Reserve estuary in Beaufort, North Carolina
This study provides novel insights into coastal shark population dynamics within the Rachel Carson reserve estuary, a hotspot for shore-based recreational activity in summer months. Understanding the intra-seasonal dynamics of this population is important because the high-abundance season for most shark coastal shark species (summer) coincides with peak shore-based activity for recreational tourism. Understanding and predicting potential conflicts and disruptions to habitat usage within this period is critical for informing potential future conservation efforts. Moreover, this study provides a breakthrough non-invasive, UAS-based methodology for observing shark abundance in temperate estuaries.
DiGiacomo, A.E.; Harrison, W.E.; Johnston, D.W.; Ridge, J.T. Elasmobranch Use of Nearshore Estuarine Habitats Responds to Fine-Scale, Intra-Seasonal Environmental Variation: Observing Coastal Shark Density in a Temperate Estuary Utilizing Unoccupied Aircraft Systems (UAS). Drones 2020, 4, 74. https://doi.org/10.3390/drones4040074
Field operations using Unoccupied Aircraft Systems (UAS) to observe coastal shark density along transects parallel to shore. (A) Study design schematic. (B) True example video frame at Bird Shoal (enlarged for visualization purposes)..
Graphical abstract for DiGiacomo et al. 2020
Modeling Salt Marsh Vegetation Height Using Unoccupied Aircraft Systems and Structure from Motion
Recent paper in Journal of Remote Sensing demonstrates DiGiacomo’s work using commercial grade drones to compute salt marsh vegetation height.
Associated Media:
https://bassconnections.duke.edu/about/news/summer-salt-marshes-using-drones-monitor-health-coastal-habitats