PARENT SESSION
Thursday, August 10, 8:00-11:30 am
COS 76 - Spatial ecology I
L-2, Lobby Level, Cook Convention Center
Presiders: E Damschen

Spatial relations of aquatic bird species and water management in the Lower Rio Grande Basin.

Weir, Enrique^*,1, ¹ The Beijer International Institute of Environmental Economics, Stockholm, Stockholm, Sweden

ABSTRACT- Alteration of water quantity and river flow regimes associated with water management is one cause of the imperilment of aquatic birds, which represent an important economic, as well as ecological, resource for the Lower Rio Grande Basin (LRGV). There is concern that the proposed modification of LRGV irrigation systems from open canals to pipelines may further restrict water availability for aquatic birds, both directly, by reducing surface area of open canals, and indirectly, by reducing runoff into the Rio Grande Wildlife Refuges Complex (RGWRC). Due to the functions and services that the RGWRC provides to wildlife it plays an important role in maintaining bird diversity in the region. I develop an object-oriented, spatially-explicit, simulation model. The model represents change in water availability in irrigation systems, and wetlands and changes in richness and abundance of aquatic birds. The impact on the richness and abundance of aquatic birds from increasing the surface area of lagoons in wildlife refuges is simulated. I spatially joined data bases in ArcGIS 9.0 (ESRI 2004), generated maps overlaying aquatic bird richness, abundance and distributions, on the irrigation systems, resacas, and lagoons and wetland areas in the wildlife refuges and state parks in the LRGV. I then (non-spatially) correlated aquatic bird abundance (data base from Weller and Weller 2000) with the area of irrigation canals, resacas and wetlands of wildlife refuges (data from Flahive and Fipps (2002) and TNRIS (2002) using the statistical program SPSS 11.0. I ran two series of 10-year simulations in which (1) the area of canals decreased by 1, 2, 3, 4, 5, 6, and 7% per year, respectively, and (2) the surface area of lagoons in wildlife refuges increased by 1, 2, 3, 4, 5, 6, and 7% per year, respectively. Simulation results indicate that with the current annual decrease in surface area of canals of 3%, it would take an annual increase in surface area of lagoons of 2 % to maintain the current abundance and species richness of the aquatic birds in the LRGV.

Key words: Spatial Explicit Model, Aquatic Bird, Lower Rio Grande