Use of continental gastropods as bioindicators of human impact in a subtropical region

Abstract

ABSTRACT This study explores the potential of continental gastropods as bioindicators of human impact within a subtropical region and contributes to the knowledge of the diversity of this group. Their limited ability to disperse makes them effective in reflecting local environmental conditions. This study aimed to assess species abundance in an ecological gradient from rural to protected urban localities in a coastal area of northwest Mexico. A qualitative human impact index was established by assigning grades of qualitative attributes for each locality and then contrasted with the frequency and abundance of the gastropod species. A total of 859 gastropods of 21 species were collected, with the first report for Sinaloa state on the non-native terrestrial species: Allopeas gracile and the freshwater species: Biomphalaria glabrata, Melanoides tuberculata, and Pomacea sp. Our results indicate that four terrestrial species were completely absent in areas with moderate impact; their absence may indicate sensitivity to environmental disturbances, which makes them potential bioindicators: Bulimulus sp., Euglandina turris, Orthalicus melanocheilus, and Tryonigens remondi. The native species showed low abundances and diversity in localities with moderate human impact index, contrasting with introduced species that exhibited high abundances; the distribution and abundance of subtropical continental gastropods reflect the environmental conditions associated with anthropogenic impact.