MID-TEXAS, USA COASTAL MARSH VEGETATION PATTERN AND DYNAMICS AS INFLUENCED BY ENVIRONMENTAL STRESS AND SNOW GOOSE HERBIVORY

• Published in: Wetlands (Wilmington, N.C.) N.C.), 2005-09, Vol.25 (3), p.648-658
• Main Authors: Miller, Deborah L., Smeins, Fred E., Webb, James W., Yager, Lisa
• Format: Article
• Language: English
• Subjects: abiotic stress; aerial photography; Annual precipitation; Anser caerulescens; Aquatic birds; Aquatic plants; coastal marsh ecotone; Coastal marshes; cyclic succession; depth; Drought; Dynamics; ecosystem management; ecotones; environmental factors; Environmental stress; Feeding; feeding behavior; geese; herbivores; Herbivory; patch dynamics; plant communities; plant growth; Precipitation; Saline water; salinity; salt marsh plants; salt tolerance; saltwater pulses; Snow; snow goose herbivory; spatial variation; surface water; Synergistic effect; temporal variation; Tropical storms; Uprooting; Vegetation; Vegetation patterns; Water levels; Waterfowl
• ISSN: 0277-5212; 1943-6246
• DOI: 10.1672/0277-5212(2005)025[0648:MUCMVP]2.0.CO;2

Vegetation pattern and dynamics were characterized across a mid-Texas, USA coastal marsh ecotone subjected to snow goose herbivory, drought, and salt-water pulses. For eight years following snow goose feeding, species cover was evaluated in heavy and light goose-use patches at increasing distances from tidal influence. Just prior to and for two years after the feeding event, drought, and several salt-water pulses associated with tropical storms typified the hydrologic dynamics of the marsh. Herbivory history was more important than distance from tidal influence, salinity, or flooding in explaining spatial and temporal vegetation pattern for three years. Precipitation variation influenced vegetation dynamics in areas heavily used by geese. Recovery to pre-herbivory composition and abundance required six years without further snow goose feeding. Extremes of annual precipitation, salinities, and water levels impacted cover of Spartina patens dominated patches little unless feeding snow geese uprooted vegetation. Schoenoplectus americanus was more impacted by extremes of environmental dynamics than S. patens but even more impacted by synergistic effects of uprooting and environmental extremes. During this period, the ecotone could be characterized as patchy, with a gulfward waxing and waning of S. americanus.