Using multispectral videography to distinguish the pattern of zonation and plant species composition in brackish water marshes of the Rio Grande Delta
- Univ. of Texas-Pan American, Edinburg, TX (United States); and others
Cyclical flooding of the Rio Grande and movement of floodwater into distributary channels formerly constituted significant freshwater input into the marshes of the Rio Grande Delta, but dams and flood control projects have eliminated this source of freshwater. The marshes are now dependent on rainfall alone for freshwater input and may be experiencing significant change in species of vegetation, abundance and patterns of distribution. Unfortunately, little is known of the ecology of these marshes. As a first step in providing needed information, multispectral videography was used to distinguish species composition and patterns of zonation in a brackish water marsh at Laguna Atascosa National Wildlife Refuge, Cameron County, Texas. The line intercept method of vegetation analysis provided ground truth and quantified species distribution and abundance. The vegetation of a typical brackish water marsh is organized into three zones along an elevation gradient. At the lowest elevations there is a distinct zone dominated by maritime saltwort, Batis maritime. At the lowest elevations in this zone where rainwater remains the longest, stands of California bulrush, Scirpus californicus, occur. An intermediate zone supports shoregrass, Monanthochloe littoralis, as the dominant species. A third (highest) zone is dominated by Gulf cordgrass, Spartina spartinae. The upper margin of this zone grades gradually into a shrub-grassland community that occurs on lomas (clay dunes). Each of the zones is distinguished by a distinctive signature in the multispectral videography. The Batis maritime community has a bright pink to red image response. Monanthochloe littoralis has a dark brown color and Spartina spartinae has a light gray to pinkish-tan color. Brackish water marshes may be distinguished from saltwater marshes by the relative positions of the Monanthochloe littoralis and Spartina spartinae communities, but additional data are needed before this possibility is confirmed.
- OSTI ID:
- 508203
- Report Number(s):
- CONF-960384-; TRN: 97:002803-0033
- Resource Relation:
- Conference: Nomadic computing and communications conference: creating a new era in mobile communications, San Jose, CA (United States), 13-15 Mar 1996; Other Information: PBD: 1997; Related Information: Is Part Of Proceedings of the fourth international conference on remote sensing for marine and coastal environments. Technology and applications: Volume II; PB: 671 p.
- Country of Publication:
- United States
- Language:
- English
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