A preliminary survey of the inland aquatic macroinvertebrate biodiversity of St. Thomas, US Virgin Islands

ABSTRACT

The use of quantitative invertebrate community indices to monitor inland water quality is widespread. However, this approach is rare for the Caribbean, where the dominant animal groups are substantially different from those in continental waters and surface water availability is strongly influenced by seasonality. For the United States Virgin Islands, these limitations are amplified by a general lack of biodiversity data on non-marine aquatic environments. To begin bridging this knowledge gap, we surveyed 41 inland aquatic sites on the island of St. Thomas and adjacent Water Island and Saba Island. Samples were obtained from lotic and lentic habitats, phytotelmata, rural and urban areas, and natural and anthropogenic settings. Out of 118 taxa across 591 records, 46% were first records for the islands sampled, with 23.4% of these being new to the US Virgin Islands territory. Shrimps and snails dominated lotic environments taxonomically, whereas insects dominated lentic environments and phytotelmata. Two confirmed undescribed species were encountered, but this is likely underestimated given the large number of juveniles encountered for some insect groups and the need for a taxonomic revision of multiple genera. The most common and widespread species was the invasive snail Melanoides tuberculata. When sampling periods or multiple samples from the same site were compared, only a 36–42% similarity was found, suggesting a much higher biodiversity than currently appreciated for these seasonally fluctuating habitats. Deep knowledge of inland aquatic biodiversity is necessary to establish baselines to assess watershed health and develop management and conservation plans in the US Virgin Islands, which in turn may be applied to other Caribbean islands.

KEYWORDS:

• Freshwater invertebrates
• ghut
• species diversity survey
• USVI
• watershed health

View correction statement:

Correction

Acknowledgements

We are very grateful to Ken Banks, Robin Bitterwolf, Sean Casey, Olivia Diana, Maricel Flores-Diaz, Thomas Lombardi, Matthew Mullins, Brice Orange, Jennifer Roslon, Moriah Sevier, and Eric Tillet, who provided logistical support, permission to sample in their properties, and/or aided in collections. We also gratefully acknowledge the following individuals for identification assistance: David Goldhammer identified our Chironomidae; Art Borkent helped with discussions and literature towards identifying our Ceratopogonidae; and Jennifer Davenport identified epigeic oligochaetes. Specimens were collected under permit DFW19068U from the Department of Planning and Natural Resources, Division of Fish and Wildlife, Government of the Virgin Islands of the United States. This is contribution #237 from the University of the Virgin Islands Center for Marine and Environmental Studies.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by 104B funding from the United States Geological Survey to the Virgin Islands Water Resources Research Institute.