Predicted
increases in sea levels will have significant effects on the natural coastal
environments. Coastal environments are
unique physical and vegetative landscape and are important habitat for many
year-round residents and migratory bird species. Increasing sea levels mean greater volume of
open water and deeper bays which could affect foraging habitat for wading
birds, such as the Reddish Egret which forages in shallow bay waters. The area of coastal salt marsh will be
reduced, affecting habitat for species such as the Whooping Crane, rails, and
Seaside Sparrow which are salt marsh specialists. Even at the lowest expected sea level rise
scenarios the lateral shifts in bayside marshes are expected to lose 1-2 km on
the Texas coast including the southern portion of our study area (Montagna et
al. 2007). Salt marshes are not the only
associations that will be affected as water level and salinities will increase
along the low-lying uplands where inundation will cause habitat shifts in
prairies and savannahs to a more estuarine environment.
The coastal areas of the Gulf of Mexico
in Texas are important areas for many bird species and populations. Year round residents are joined by hundreds
of species and millions of individuals of migratory and winter resident birds
from fall to spring time. Aransas National Wildlife Refuge has recorded 405
species of birds. Many factors influence the number of species observed in this
area, which includes the diversity of environments and plant communities found
overs short distances. The variety of habitat types include beaches and flats,
coastal salt marshes and open water, salty and upland grasslands, freshwater
wetlands, and oak shrublands and woodlands. In addition, the central Texas
coast is a major migratory corridor for birds travelling between North and
South America so many North American species that breed farther north may be
seen during the spring and fall migration in this area. A unique feature of the
central Texas coast is that it is the winter home of the Whooping Crane, which
is the only place in the world where it is found naturally during the winter
months.
The overall goal of this project employs the
conservation design approach to develop habitat type maps using available
spatial environmental data for Whooping Crane, and other selected bird species
of concern in Aransas, San Antonio, and Matagorda Bay systems. These maps incorporate species-specific
habitat requirements and define current habitat types available as well as
evaluate how landscape changes likely to occur under various sea-level rise
scenarios will affect conservation strategies.
Specific project objectives were to:
-
Create a Composite Habitat Type Dataset that
identifies spatial location and extent of coastal habitat types, developed
lands, and protected areas in GCPLCC pilot project area.
- Estimate the amount
and spatial configuration of habitat type needs for Whooping Cranes in the pilot
project area
-
Develop projections of the amount and spatial
configuration of appropriate habitat types and evaluate potential impacts on
selected bird species numbers.
-
Construct maps that
depict habitat type shifts in coastal prairie and marshes under various
sea-level rise scenarios and define the shifts in habitat availability and
extent for the Whooping Crane and other selected species.
-
Recommend ways to apply methods used to
develop these projections to extend results to additional areas within the Gulf
Coast Prairies and Marshes Ecoregion.
Final deliverable datasets are below