Mid-Texas coastal marsh change (1939-1991) as influenced by lesser snow goose herbivory
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Authors: D. L. Miller, F. E. Smeins, and J. W. Webb
Date: 1996
Journal: Journal of Coastal Research
Volume: 12
Number: 2
Pages: 462-476
Summary of Methods: Aerial photographs were used to quantify the pattern changes of vegetation/mudflats/open water within the SBNWR salt marsh from1939 to1991 in Brazoria County, Texas (28° 55' N, 95° 35' W). Four land type categories were identified; area of each type estimated and mapped using aerial photographs. The site was continuously vegetated in 1939 and has been grazed by cattle and wintering lesser snow goose (LSG) since the refuge was established in 1968. The Information regarding LSG numbers and their feeding habits, marsh burning, cattle grazing, tide levels, and precipitation were collected.
Article Summary / Main Points: Vegetated marsh areas which were heavily grazed by lesser snow geese (LSG) were transformed to mudflats and open water, while unvegetated marsh increased from <4% (1939) to 21% (1991). Establishment of mudflats resulted from a combination of disturbance agents; including extreme environmental conditions (extremes of inter- and intra-annual tide levels, surface water and interstitial soil water salinity, and precipitation). Some of the mudflats have revegetated and some have become deep open-water areas over time. Denudation rate increased from 1950 to 1970 as the number of LSG increased from 300,000 to 1,000,000. Vegetation loss and soil erosion occurred with repeated and intense LSG feeding followed by frequent tidal inundation, high soil and water salinities and extended droughts.
Vegetation Types: Riparian and Wetlands
MLRA Ecoregions: 150A Gulf Coast Prairies 150B Gulf Coast Saline Prairies
Agrovoc Control Words: Riparian zones Grazing Wildlife
Article Review Type: Refereed
Article Type: Documented Case History
Keywords: distichlis spicata, disturbance, landscape pattern dynamics, patch dynamics, fire, cattle herbivory, wetland vegetation loss, gis
Annotation: This non replicated study and its findings are applicable to coastal saline prairies and marshes grazed by lesser snow geese. These results illustrate how repeated and heavy grazing can result in vegetation loss, soil erosion, and landscape changes in other communities. The effects of livestock grazing and burning were not examined.
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