Using Unmanned Aerial Systems (UAS) Capabilities to Help Identify Hummock-Hollow Formation and Fragmentation in Critical Marsh Habitat for Mottled Ducks

Science Center Objects

For many years, coastal marshes in Texas and Louisiana have served as critical habitat for the mottled duck (Anas fulvigula), which is considered a priority species in the Texas/Louisiana Gulf Coast area.

 McFaddin Project D1 site boundary with 4 ground control points

McFaddin Project D1 site boundary with 4 ground control points

The Science Issue and RelevanceFor many years, coastal marshes in Texas and Louisiana have served as critical habitat for the mottled duck (Anas fulvigula), which is considered a priority species in the Texas/Louisiana Gulf Coast area. In recent years, the marsh habitats, Spartina patens have been threatened by flooding, saltwater intrusion, and hydrologic alterations, which are affecting the quality of habitats essential for the mottled ducks’ nesting, feeding, and living needs. In some areas these habitats have been replaced by more salt tolerant marshes and in some cases a complete habitat loss. Cumulative and synergistic effects of contamination and invasive species encroachment have also caused mottled duck habitat to be considered some of the most critically endangered habitats in the United States. To help understand the environmental changes that are taking place on the coastal landscape, unmanned aerial systems (UAS) were used to acquire high-resolution imagery to document current land and water fragmentation, degradation, and distribution in critical marsh habitat (Spartina patens) for mottled ducks.

Land/Water Classification of McFaddin Site D1

Land/Water Classification of McFaddin Site D1

Methodology for Addressing Issue: The 3DR Solo UAS, a quadrocopter designed to carry a single sensor and/or camera to capture remotely sensed data, was used to fly this mission. Automated flight plans were developed for each of the six study areas. For continuous and complete coverage, a flight plan with a 60% end lap and 60% side lap was created. Side and end laps refer to the amount of image overlap between photos which is done to reduce the chance for missing imagery coverage, also known as holidays. The altitude for this mission was 350 feet above ground level. At this elevation a pixel resolution or Ground Sample Distance (GSD) of 1.18 inches (0.03 meters) is achieved. To acquire the imagery, the Ricoh GR II digital single lens camera captured individual frames at five second intervals for each of the six study areas. These frames were used to create a seamless orthomosaic using the red, green, and blue visible light spectrum (natural color). These were then classified into land and water categories. With the land and water classification data, spatial components of the data (clump size, spatial proximity) can be calculated to better understand habitat characteristics.

Future Steps: The imagery collected from the UAS will be analyzed to better understand the status of mottled duck habitat in Texas and Louisiana. We also intend on applying this new technology to mapping landscapes during high-stress, time-sensitive events, such as severe storms and other natural hazards.