Wigeongrass (Ruppia maritima), a submerged aquatic plant inhabiting estuarine wetlands, is an important winter food for waterbirds along the Texas Gulf Coast. We examined availability of wigeongrass at Mad Island Wildlife Management Area, Texas, USA by estimating aboveground biomass from October through January, 1998–1999 and 2001–2002. We also used an exclosure experiment to determine the extent to which herbivory by waterbirds was responsible for depletion of wigeongrass. Aboveground biomass of wigeongrass declined an average of 189 g m−2 and 71 g m−2 between October and January each year. Aboveground biomass declined at a higher rate among plots exposed to herbivory compared to exclosures, and the loss of biomass attributable to foraging by waterbirds was 19%. In 1998, counts of gadwalls (Anas strepera), American wigeons (A. americana), and American coots (Fulica americana) using study ponds peaked in November and then followed a declining trend similar to availability of wigeongrass, suggesting that as wigeongrass was depleted herbivorous waterbirds moved to other habitats where food was more available.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.
Vol. 29 • No. 1