Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Titre : The Conservation of Native Snails Within A Chihuahuan Desert spring System

Auteur : Hallie L A Ladd

Université de soutenance : Texas Tech Univeristy

Grade : Master of Science 2010

Résumé partiel
Aquatic biodiversity in the Chihuahuan Desert of West Texas is an important national resource and conservation concern because of the high levels of endemism, limited distributions of natural communities, and the continuing decline of water resources. The Diamond Y Spring preserve located in Pecos County, Texas contains two endemic springsnails (Tryonia circumstriata=stocktonensis and Pseudotryonia=Tryonia adamantia, family Hydrobiidae), one federally endangered snail (Assiminea pecos), one common pond snail (Physella spp.), and one invasive snail (Melanoides tuberculatus, family Thiaridae). The potential impact of this invasive snail is of concern as it has been documented to outcompete and eradicate populations of native snails. In addition, the red-rimmed melania snail also poses the potential threat of introducing non-native parasites into novel environments. Our study objectives were to determine the habitat associations, distribution, and densities of each of the snail species within the Diamond Y Spring preserve and investigate how the invasive Melanoides affects native species. We conducted a field study over the course of one year (June 2009 to July 2010) at three spring systems (Diamond Y, Bird, and Euphrasia) within the preserve. Only two snails, Assiminea pecos and Physella spp. were found throughout all three spring systems. Melanoides tuberculatus and T. circumstriata were found only within Diamond Y Spring, while P. adamantia was found only within Euphrasia Spring. The invasive Melanoides tuberculatus was the most abundant snail within the Diamond Y Spring preserve and the endemic T. circumstriata was the least abundant snail within the preserve. We found that the variation in snail densities was strongly associated with one or two habitat variables.

Mots Clés : Diamond Y Spring Preserve — Melanoides Tuberculatus – Springsnails — Chihuahuan

Présentation

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