Distribution, population dynamics and potential impacts of the invasive snail, Tarebia granifera in aquatic ecosystems of north-eastern South Africa

Aquatic ecosystems globally have been invaded by molluscs. Tarebia granifera is a highly successful invader, often becoming the dominant aquatic invertebrate species in an invaded ecosystem. Resultingly, it has been suggested that T. granifera may have severe negative impacts on these invaded ecosystems. Limited information is available regarding the population structures and densities of T. granifera, particularly in invaded countries such as South Africa, and information on this could assist in developing management and control strategies for this invasive species. The aim of the present study was to assess the current distribution, densities, and population structures of T. granifera in invaded habitats on the Limpopo and Phongolo River systems, South Africa. This was accomplished by collecting aquatic benthic molluscs from sites across these systems. Water quality parameters were measured at each site and water samples collected for chemical nutrient analyses. The density of snails ..., Nineteen sites were selected for sampling in this study based on known distributions of aquatic snails (invasive and native) and accessibility to sites (Figure 1). Four sites were sampled on the lower Phongolo River in northern KwaZulu-Natal (August – September 2017), South Africa, and a total of 15 sites were sampled on the Limpopo River and its tributaries (Limpopo River system), in the Mpumalanga and Limpopo provinces of South Africa (April – May 2021). Two sites in the Limpopo River system on the Olifants River (OLIF-1, OLIF-2) were sampled in consecutive years (2020 and 2021). 
Mollusc sampling and identification
Each of the 19 selected sites was sampled for aquatic benthic molluscs (including snails and bivalves/clams), using a metal-frame square benthic sampler (30 x 30 cm, 2 mm mesh size). The sampler was used to scoop up sediment and sieve through the benthic zone of the river. Random samples, each comprising three replicates consisting of ten scoops per replicate (30 sampler s..., , # Tarebia granifera and other benthic snails abundances and associated Water Quality at selected sites of easterly flowing rivers in South Africa

## Description of the data and file structure

The data for this paper is all within a single Excel file. Each tab in the file is associated with a different metric across the 19 sites. These include Abundance, density and percentage contribution of size classes to a population and/or species to a community. Site names correspond to those used in the article.

###### Site-Specific Information - Relevant to all data sheets in the Excel file

1.) Numbers in parentheses refer to the year the site was sampled.

2.) Four letter site code refers to the specific river: PHON = Phongolo River, OLIF = Olifants River, LIMP = Limpopo River, MOGA = Mogalakwena River, LUVU = Luvuvhu River, G-LETA = Groot Letaba River, LETA = Letaba River, SHIN = Shingwedzi River.

3.) Number following the site code indicates upstream to downstream. i.e. 1 is the most ups...