grand bay nerr GIS and maps

GIS Projects

GIS Analysis of Nesting Habitat for the Endangered Mississippi Sandhill Crane: Potential Habitat Suitability and Management Implications for Restoration

Historically, the Grand Bay Savanna was used as nesting and feeding territory for the federally endangered Mississippi Sand Hill Crane. Management and restoration of this area is predicated on the controlled use of prescribed fire to set back succession and prevent the invasion of undesirable woody vegetation. Budget limitations, weather uncertainties, and the complexity of state, federal, and private ownerships within the savanna make the application of fire difficult. These factors, along with changes in land use patterns, have rendered some portions of the Grand Bay Savanna unsuitable as habitat for the Mississippi Sand Hill Crane. In an attempt to better direct restoration and prioritize prescribed fire activities within the savanna, scientists from the Grand Bay NERR have partnered with the Mississippi Sand Hill Crane and Grand Bay National Wildlife Refuges. The unique collaboration will result in the development of a GIS based habitat suitability model that will be used to predict the suitability of areas within the savanna for cranes. Experimental releases of cranes will be targeted for areas predicted to provide suitable nesting and foraging habitats. Additionally, the model will be used to prioritize the acquisition of real estate parcels in the area.

Oyster Resource Mapping

The primary objective of Phase I of the Oyster Inventory Survey Project is to map existing intertidal oyster reefs, dead and alive, along the intertidal zones of bays, bayous, and lakes located within the boundary of the Grand Bay NERR. Areas containing oyster shells are mapped according to a percent cover classification scheme that will ultimately improve the management strategy for oyster reef protection and restoration. Where waters are turbid, oyster reefs are observed during low-tide events to obtain the maximum extent of oyster shell coverage and plotted by hand using six inch high-resolution, true-color orthoimagery. Oyster presence is then digitized in a GIS and stored in a geodatabase.  Click here for additional information.

Habitat Mapping and Change

The Reserve System intends to monitor long-term trends in the geographic extent of habitats in relation to local sea level change and anthropogenic stress from adjacent watersheds.  The Reserve System has developed a habitat mapping and change plan to support research and monitoring on the impacts of climate change and anthropogenic pressures from reserve watersheds on reserve resources.  The plan calls for each reserve to map critical habitats over time consistent with site-based habitat mapping and change plans using the standard Reserve Classification System .

Shoreline Change Analysis

The Grand Bay NERR is an estuarine system that is naturally retrograding. Over time the rivers that historically flowed through the Reserve have shifted and diverted to other basins, allowing erosion from wave action and storm surges to “out pace” sediment accretion in the marsh. Erosion is an important component to landscape change and this change needs to be documented, especially when considering sea level rise due to climate change. Staff at the Reserve are currently using high-tech GPS and surveying equipment to monitor shoreline fluctuations. A RTK (real time kinematic) positioning system and a total station surveying unit record shoreline positions with centimeter accuracy. Additionally, historic shorelines derived from old maps are used to model the amount of shoreline change over decades of time.

Historical Imagery and Map Analysis

Historical aerial photos and maps are direct links to the past and can help us understand how natural processes and anthropogenic influences have changed the landscape over time.  The Grand Bay NERR maintains an extensive library of aerial photos, satellite images, and old maps to help us assess physical and ecological land use changes over time.