Major Research Gives New Insights Into the Needs of Whooping Cranes
- Impact to Whooping Cranes Is More Complex Than Previously Thought
The report, “Linking Freshwater Inflows and Marsh Community Dynamics in San Antonio Bay to Whooping Cranes,” was prepared by Dr.
“What the research showed is that the whooping crane diet and the impact of inflows and other stimuli on whooping cranes is very complex,” said Slack, professor and associate department head of Undergraduate Programs, Department of Wildlife and Fisheries Sciences at
“Prior to this study, there was little detailed science about the effects of freshwater inflows on whooping crane ecology,” explained Dr.
The SAGES research, however, indicate that while in the salt marsh, whooping crane diet consisted of wolfberry fruit, blue crabs, clams, snails, insects, fiddler crabs, snakes and fish. Wolfberry fruit and snails and insects were consumed in the highest quantities and required the least effort to obtain by the cranes during foraging.
Additionally, the research showed that while blue crabs were the most optimal food for the cranes in relation to protein, clams proved to be a substantial source of biomass. An adverse effect of salinity on crabs and cranes was not observed. However, it is recognized that more research is needed to fully understand the bay and marsh ecosystems.
In summarizing the study, researchers commented that in nearly all conditions simulated, the food supply for whooping cranes appears to be more than adequate to meet their energy needs. “During extended droughts, there are environmental changes to the landscape, and some of these are related to fresh water inflows. Whooping cranes will be affected under these extremes as are other wildlife,” noted Dr.
In an effort to secure the study’s objectivity and provide peer review support to the research team, Wilson recruited a diverse group of professionals to serve on the SAGES Scientific Advisory Panel. Members and their affiliations in 2003 and 2004 included Dr.
Slack estimated thousands of hours of fieldwork were completed over the seven years of research. Similar amounts of time were spent completing work in the laboratory, university offices and computer labs at
The SAGES study was primarily funded by the Guadalupe-Blanco River Authority (GBRA) and San Antonio River Authority (SARA). The sponsors were interested in assessing impacts from the Lower Guadalupe Water Supply Project (LGWSP) in which GBRA water rights would have been leased to San Antonio Water System (SAWS) and SARA and water would have been diverted from near GBRA’s Salt Water Barrier in the lower basin, which is about 11 miles from San Antonio Bay. In considering whether the water diversion could affect the bay, the entities involved in the LGWSP initiated the SAGES study through Texas A&M University’s Department of Wildlife and Fisheries Sciences.
When the LGWSP was canceled in 2006, SAWS discontinued its funding of the SAGES study. SARA and GBRA continued to fund the study, recognizing its importance and the potential for other water supply projects and future growth and economic development needs. Other monetary funding and in-kind support for the SAGES study was provided by the Texas Water Development Board, the U.S. Fish and Wildlife Service, and the U.S. Geological Survey.
Additionally, SARA and GBRA entered into an agreement with researchers with the
“Without having other partners, GBRA and SARA could not afford to fund both studies simultaneously,”
“Both of these studies will be important to consider as state officials try to determine requirements for the environmental flows process, which was established in Section 2 of the omnibus water bill (Senate Bill 3) from the 2007 Legislative Session,” added
The GBRA was established by the Texas Legislature in 1933 as a water conservation and reclamation district. GBRA provides stewardship for the water resources in its 10-county statutory district, which begins near the headwaters of the Guadalupe and Blanco rivers, ends at San Antonio Bay, and includes
SARA is entrusted to protect and preserve its shared water resources and, together with its partners, pursue innovative solutions that will serve generations to come. SARA’s district spans
SOURCE Guadalupe-Blanco River Authority