In 2010, Linda received the Meritorious Service Award of the Department of the Interior for her leadership in the formation, development, and implementation of the Southeast Aquatic Resources Partnership (SARP), a regional collaboration of state and federal natural resource and science agencies, conservation organizations, and private interests working to strengthen the management and conservation of the aquatic resources in the southeastern United States.  Her promotion of this concept of locally-driven efforts that build private and public partnerships to improve aquatic resources was so successful that SARP was selected as one of the first Fish Habitat Partnerships for the National Fish Habitat Initiative.  She served as SARP's Co-Chair until her retirement.  She was also given the Meritorious Service Award for her role in seeking reimbursement for the Fisheries Program's hatchery mitigation expenditures associated with federal water development agencies.  For many decades, the Fisheries Program mitigated the fisheries impacts of these projects using its own operational funding.  By securing this reimbursement, much needed Service funding was freed up to support other high priority fisheries program activities. 

An innovative application of existing landsat data is providing land managers with information on some of the key variables that affect fish and other aquatic species: extent of inundation through time, water temperature, and ultimately the dynamic nature of floodplain habitat itself.  Partners working at St. Catherine's Creek National Wildlife Refuge (SCC NWR) initiated this project to assess habitat suitability for alligator gar in response to requests from state agencies seeking guidance on how best to manage this species of conservation concern.  What they have created is a Habitat Suitability Index methodology that has the potential to be applied to any species that responds significantly to water temperature, inundation frequency and land cover type.  Moreover, their techniques can also identify the most suitable habitats for protection, management or restoration of each such species using remote sensing.

Thinking Like a Gar

Gar are large apex predators that have been extirpated from parts of their range in 7 of the GCPO's 12 states.  With a reputation that has been rehabilitated from "trash fish" to "game fish," they are also increasingly popular among sportsmen, and wildlife agencies in most states with gar want to help maintain and expand healthy populations.  A key part of this is protecting or restoring gar spawning habitats.  The question has been, what makes alligator gar key in to certain habitats for spawning at certain times?

In 2010, the alligator gar project began.  It combines data from 24 separate landsat images taken of the SCC area from 1985 to 2011, all of which meet the criteria of being cloud-free and taken from December to March (for maximum accuracy).  SCC NWR is the only refuge located within the study area still subject to direct inundation from the Mississippi River.  By analyzing these photos in correlation with river stage and landsat thermal data, Yvonne Allen, Aquatic Habitat Analyst for the GCPO LCC, was able to develop a model that shows how inundation and temperatures in the area change according to river stage. 

These data were ground-truthed from 2010 to 2013 using water quality data loggers placed at key sites on the refuge.  "The data loggers told us that what we think we're seeing - in terms of water, temperature and turbidity - is actually there," explains Allen.  Telemetry tracking of 20 gar per year, 60 total, told researchers which habitats gar were using at which times.  From these analyses emerged the alligator gar Habitat Suitability Index, which shows that the warmest parts of the floodplain that are inundated roughly 50% of the time tend to be the most important for gar.  These areas are generally 4 to 5 degrees warmer than river temperature, and tend to be open canopy.  Biologists are now thinking that temperature is the spawning trigger.  Thinking like a gar, you want to get to the warmest places for eggs to incubate properly because just a few degrees drop can cause lots of problems (such as fungal accumulation). 

Serendipitously, the qualities that gar seem to prefer in their spawning habitat are often associated with moist soil units managed on the refuge to provide migratory waterfowl habitat.  To get at this last piece of the puzzle, Allen added the 2012 cropland data layer to her analysis.  This dataset is produced by the USDA National Agricultural Statistics Service, and it includes not only crop type but also woody wetlands.  This analysis indicates that mowed fallow fields, moist soil units, and even barren dirt with vegetation at field edges all seem to provide the structure and temperature, when water is present at the right times, to support gar spawning.

To read the full-text article and learn more about how to access alligator gar data layers click here.