Geotargeting spatial and temporal data of Italian freshwater high-altitude macroinvertebrates

Macroinvertebrates sampling was performed following the standard sampling methodologies developed within NIVA and, more recently, ICP WATERS Manuals and Programmes (NIVA 1987; ICP Waters Programme Centre 1996, 2010). Semi-quantitative macroinvertebrate samples were taken, during the ice-free season, mainly in Autumn before insect diapause, through a 2-5 min handle-netting the substrate (250 μm mesh size). At the same time, 1 L water bottle for water chemistry analyses was taken at lake-mouth where littoral water temperatures have also been recorded through a thermometer. Different habitats were considered (gravel, pebbles, boulders, rock faces) over a 0.5-1.0 m littoral- or river-reaches sampling. Sorting and identification were performed at genus/species level using Italian macroinvertebrate identification guides based each on single taxa group (AA.VV. 1977-1985), or on European identification guides on oligochaetes (Timm, 2009; Schmelz and Collado, 2010), or on chironomids (Andersen et al., 2013).

A data set including information on macroinvertebrates identified to genus/species gr./species level was created within the monitoring activities of several European and national projects. The data set includes 2115 macroinvertebrate records on temporal fragmentary data from lakes Paione (upper, middle, and lower lakes Paione), and 530 records on spatial data relative to eigth other high-altitude lakes from the Ossola Valley (North-western Italy, Piedmont, Central Alps). The study area is included within the Lake Maggiore watershed. All records are georeferenced because, since the beginning of the studies, temporal data were taken in the same sampling sites over years. The temporal data span over the period 1989-2020, the spatial data refer to the 2019-2020 sampling activity.

Quality control was performed using a Spell Checker to correct the spelling of names, and Google maps identification of lakes, altitude, latitude and longitude coordinates standardized to WGS84 DD. The absence of anomalous ASCII characters in the dataset was also additionally checked.