Name
Mapping intertidal zones and identifying ephemeral Reddish Egret foraging habitat in the northern Gulf of America
Date & Time
Thursday, May 7, 2026, 11:15 AM - 11:30 AM
Description

Effective conservation of wading birds such as the Reddish Egret (Egretta rufescens, hereafter REEG) requires the identification and protection of habitat regardless of use (e.g., nesting or foraging). Waders like REEG are dietary generalists, and thus foraging habitat is typically determined by environmental factors such as the depth of water in ephemerally wet (i.e., intertidal) areas. We used remote sensing data to map these intertidal zones using the Modified Normalized Difference Water Index (MNDWI). Following this, we estimated intertidal topobathymetry using identified intertidal zones, NOAA tidal gauge data, and remotely sensed images for the northern Gulf of America in the years 2020 – 2024. We combined this intertidal elevation raster with topography and bathymetry DEMs to create a combined topobathymetry raster for the region. This elevation raster – along with tidal gauge data and preferred foraging depths for REEG – was input to a Tidal Model of Shallow-Water Availability (TiMSA) simulation to determine areas of suitable depth for the considered period. Ultimately, this TiMSA model output raster maps for the northern Gulf displaying the mean number of minutes in a day that a given area is of suitable depth to qualify as REEG foraging habitat.  We determined high-frequency foraging habitat from this raster for REEG, with frequently suitable areas likely to be critical to conserving the species. To the extent possible, we repeated the TiMSA model for other wading birds (e.g., Tricolored Heron, Little Blue Heron). The ephemeral nature of suitable foraging habitat for wading birds (e.g., REEG) makes it difficult to identify crucial foraging areas but does not reduce the importance of such areas to the conservation efforts for these rare birds. This model could be repeated with readily available multi-spectral satellite imagery for other areas of interest (e.g., the southern Gulf) if local tidal gauge data is available.

Location Name
202B
Is presenter a student?
No