Habitat characterization of Texas wild-rice (Zizania texana Hitchcock), an endangered aquatic macrophyte from the San Marcos River
- Permanent Link:
- Habitat characterization of Texas wild-rice (Zizania texana Hitchcock), an endangered aquatic macrophyte from the San Marcos River
- Series Title:
- AQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS
- Poole, Jackie
Bowles, David E.
- John Wiley & Sons, Ltd.
- Publication Date:
- Subjects / Keywords:
- Texas Wild Rice ( local )
Zizania Texana ( local )
Endangered Species ( local )
Habitat Characterization ( local )
- serial ( sobekcm )
- 1.â€…The habitat of Texas wildâ€rice (Zizania texana Hitchcock), known only from the springâ€fed upper San Marcos River in Central Texas, was classified in terms of physical and chemical conditions, depth, current velocity, associated aquatic macrophytes, and substrate composition.
2.â€…Randomly selected transects in sites with and without Texas wildâ€rice were evaluated during May, August and January 1994â€“1995. Physical and chemical conditions (temperature, dissolved oxygen, specific conductance, pH) were found to be nearly constant and uniform both among transect types and sampling dates. Chemical analysis of the substrate likewise showed few differences among transect types. Turbidity was found to be significantly different among transect types on only one sampling date (KÎ±0.05=0.60; p=0.009), but even nonâ€significant levels of turbidity may present biologically significant impacts to wildâ€rice plants.
3.â€…Differences in substrate particle size were highly significant (KÎ±0.05=0.71; p=0.001) with Texas wildâ€rice occupying sites having moderately coarse to coarse sandy soils (73%) compared with the moderately fine to fine clay soils found at nonâ€rice sites (82%). However, no significant differences were found in organic matter content among rice and nonâ€rice transects (=2.09 and 2.56%, respectively).
4.â€…Texas wildâ€rice was found primarily in shallow areas of the river (<1 m) and at higher current velocities than those of nonâ€rice sites (â‰¥0.46 mâ€…sâˆ’1 and â‰¤0.22 mâ€…sâˆ’1, respectively).
5.â€…Texas wildâ€rice appears to be more commonly associated with other native species rather than exotic species. Mean percentage composition of exotic macrophytes did not exceed 29% in areas where Texas wildâ€rice grew, but they accounted for nearly 47% of the composition in areas where rice did not grow.
6.â€…The results of this study will allow for reliable and accurate identification of the remaining suitable habitat of Texas wildâ€rice in the San Marcos River for possible reintroduction and development of management plans.
- Original Version:
- AQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Vol. 9, no. 3 (1999-06-02).
- Source Institution:
- University of South Florida Library
- Holding Location:
- University of South Florida
- Rights Management:
- This object is protected by copyright, and is made available here for research and educational purposes. Permission to reuse, publish, or reproduce the object beyond the bounds of Fair Use or other exemptions to copyright law must be obtained from the copyright holder.
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