Seasonal variation in utilization of biogenic microhabitats by littorinid snails on tropical rocky shores

Abstract

Mobile species may actively seek refuge from stressful conditions in biogenic habitats on rocky shores. In Hong Kong, the upper intertidal zone is extremely stressful, especially in summer when organisms are emersed for long periods in hot desiccating conditions. As a result, many species migrate downshore between winter and summer to reduce these stressful conditions. The littorinids Echinolittorina malaccana and E. vidua, for example, are found on open rock surfaces high on the shore in winter but the majority migrate downshore in summer to the same tidal height as a common barnacle, Tetraclita japonica. In the laboratory, where environmental conditions could be controlled to approximate those occurring on the shore, we tested whether the downshore migration allowed littorinids to select barnacles as biogenic habitats to reduce stress and if this behaviour varied between seasons. In summer, littorinids demonstrated a strong active preference for the barnacles, which was not observed in the cool winter conditions, when animals were found on open rock surfaces even when barnacles were present. Littorinids, therefore, only actively select biogenic habitats during the summer in Hong Kong when they migrate downshore, suggesting that such habitats may play an important, temporal, role in mitigating environmental stress on tropical shores.

Not all space is created equal: Distribution of free space and its influence on heat-stress and the limpet Patelloida latistrigata

“…Intertidal barnacles have been shown to mitigate thermal stress for a wide variety of taxa (Barnes, 2000;Cartwright and Williams, 2012;Harley, 2006;Lathlean et al, 2012;Thompson et al, 1996). For example, during winter on tropical rocky shores in Hong Kong the gastropods Echinolittorina malaccana and E. vidua are predominantly found on open rock surfaces, whilst in summer they migrate to areas dominated by the barnacle Tetraclita japonica (Cartwright and Williams, 2012).…”

“…For example, during winter on tropical rocky shores in Hong Kong the gastropods Echinolittorina malaccana and E. vidua are predominantly found on open rock surfaces, whilst in summer they migrate to areas dominated by the barnacle Tetraclita japonica (Cartwright and Williams, 2012). Here, the interstitial spaces between barnacle tests (i.e.…”

Latitudinal- and local-scale variations in a rocky intertidal interaction web

“…Due to the large size of these herbivores relative to the size of barnacles, we expected limpets to be limited in their grazing activity both between and over barnacle shells (Creese 1982 and references therein). In addition, we hypothesized a direct positive effect of barnacles on MPB biomass and photosynthetic activity due to the provision of a biogenic refuge from higher thermal and desiccation stress, as has been observed for littorinids and mussels (Kawai & Tokeshi 2004, Cartwright & Williams 2012; this effect was ex pected to be larger at southern than at northern sites. We also expected barnacle shells to represent a favourable habitat for the grazing activity of littorinids due to the small size of these grazers relative to that of barnacles (Creese 1982, Díaz et al 2012.…”

“…They can overcome relatively mild stressful conditions through physiological or behavioral adaptation (Garrity 1984, Somero 2002. At southern, warmer sites, however, they may have actively sought a refuge from desiccation by moving to areas shaded by barnacles (Cartwright & Williams 2012). As littorinids can graze over and between barnacle shells (Creese 1982, Díaz et al 2012, barnacles might have caused a negative indirect effect on MPB biomass, possibly counterbalancing the positive direct one.…”

Artificial structures in sediment-dominated estuaries and their possible influences on the ecosystem

“…Barbier et al, 2011). Though groynes and jetties represent artificial substrates, their structure is highly complex on a macro-scale (>10 cm) and provides a combination of hard substrate, crevices, pits, and rock pools which provide refuges for many species (Bracewell et al, 2012;Cartwright and Williams, 2012). Artificial reefs, for example, can facilitate and enhance marine communities in coastal and deep-sea environments and provide benefit for ecosystem services in sediment dominated environments (Macreadie et al, 2011).…”