An evaluation of avian use of a rice-wetland system

Abstract

Numerous natural depressions exist throughout the landscape in the rice belt of the Upper Gulf Coast of Texas, providing temporary wetland habitat for wildlife. The rice-agriculture system also provides shallow and deep water habitats such as flooded rice fields and canals. This study was conducted to compare seasonal use of managed agricultural water areas to seasonal use of natural depressions by waterbird species. Study sites (natural depressions, flooded rice fields, canals, ponds, and roost ponds) were randon-dy chosen. Sites were surveyed bimonthly from May 1995 to May 1996, and species and numbers of birds located on or adjacent to the sites were recorded. Bird diversity was significantly (P < 0.01) higher in roost ponds and rice fields than in canals, ponds, or depressions. Bird diversity was not significantly different among seasons. Bird diversity was significantly correlated with season (!! < 0.0087) and area of site (P < 0. 000 1). Avian species richness was also significantly correlated with season (P < 0.0001) and area of site (P < 0.0001). The comparison of natural depressions to managed water areas was hindered by a drought experienced in Texas in 1995-96. This study emphasizes the importance of providing water sources for birds throughout the year, but most importantly, in the fall and winter.