Colonization of prosobranch gastropods onto artificial substrates: Seasonal patterns between habitat patches

Abstract

We used artificial substrates to investigate the seasonal variation in colonization patterns of subtidal prosobranch gastropods in Gran Canaria (Canary Island, Spain, north-eastern Atlantic), via monthly deployment of artificial substrates throughout an entire annual cycle from February 2009 to January 2010, on each of four habitat patches (seagrasses, sandy patches, ‘urchin-grazed’ barrens and macroalgaldominated beds) within a coastal landscape. A total of 8,524 prosobranch gastropods, including 12 dominant taxa, were collected as postlarval, juvenile, and adult individuals. In general the amount of variability explained by the type of habitat slightly dominated over seasonal variation, which was outweighed by variation from month to month, to explain colonization patterns. Throughout the study, larger numbers of colonizers of Bittium spp. (Leach in Gray, 1847), Columbella adansoni (Menke, 1853), Gibberula caelata (Monterosato, 1877), Mitra spp. (Lamarck, 1798), Rissoa spp. (Freminville in Desmarest, 1814), and Smaragdia viridis (Linnaeus, 1758) were observed in artificial substrates deployed in vegetated substrates, highlighting the relevance of vegetation as a matrix habitat for subtidal prosobranch gastropods. Cerithium rupestre (Risso, 1986) and Clavatula mystica (Reeve, 1843), however, were mainly observed on sandy patches. Rissoa spp. showed a peak in the arrival of new colonizers during spring-early summer whereas Tricolia pullus canarica (Nordsieck, 1973) showed a peak during winterearly spring. Importantly, the other prosobranch gastropods did not show significant differences in the arrival of colonizers between annual seasons. In summary, these results demonstrate that seasonality is strongly outweighed by small-scale temporal variability (here variation from month to month) and the type of habitat patch as drivers of prosobranch gastropod colonization patterns in coastal landscapes.