Collecting, screening, and picking through samples of leaf litter can be an effective means of finding the most minute of land snails. As part of a research project funding in part by the Ottawa Field-Naturalists’ Club, in August/September 2016 fieldwork that used this technique was undertaken.
I’m working on sorting samples into species now, having just finished picking snails out of the litter samples. As an example of what can be found at a species-rich site, here’s a photo of part of the unsorted material.
Unsorted microsnails. Seen here, Helicodiscus parallelus (centre, pale snail), Paravitrea multidentata (to the left of Helicodiscus), Strobilops labyrinthicus (other large snails), Carychium exile (pale, slender snails),and Gastrocopta pentodon (toothy snail in hiding), and several other species. For scale, the central snail, Helicodiscus parallelus is 2.1 mm in maximum diameter.
This sample came from Morris Island Conservation Area, at the north edge of Ottawa.
Fourteen species were collected, including: Carychium exile, Columella edentula, Discus catskillensis, Euconulus polygyratus, Gastrocopta pentodon, Helicodiscus parallelus, Nesovitrea binneyana, Paravitrea multidentata, Punctum minutissimum, Striatura exigua, S. milium, Strobilops aenus, S. labyrinthicus, and Zonitoides arboreus In all, 293 specimens were recovered from the sample; with the most common species, C. exile, represented by 134 specimens (46% of the total).
Re-collected was Strobilops aeneus, a rare species that was previously found at this site and documented here: notes.on.mollus.ca and Check List journal.