Is the burrowing performance of a sandy beach surfing gastropod limiting for its macroscale distribution?
- 181 Downloads
The size-specific burrowing capacity of Olivella semistriata, an extremely abundant surfing gastropod of exposed sandy beaches in the tropical East Pacific, was investigated in terms of sediment grain size. For all investigated sand classes, there was a significant increase in burial time with size. Burrowing was fastest in sand with grain size between 150 and 355 μm, as well as in native sediment (median grain size 209 μm) and in field conditions (median grain size 223 μm). Values of the burrowing rate index (BRI) were found to be between 3 and 7, rating the burrowing capacity of O. semistriata to be fast to very fast. Data from previous qualitative and quantitative sampling campaigns were used to identify the macroscale (i.e., between beaches) distribution of O. semistriata in terms of sediment grain size and swash conditions. Swash period was shorter than burial time, excluding this as a factor limiting the distribution. Swash standstill time (the time between uprush and backwash), however, was just long enough on the beaches, where O. semistriata was present to allow for securing firm anchorage. On reflective beaches, the swash standstill time is as short as 1 or 2 s, denying O. semistriata the time to burry itself before being swept away by the backwash. As such, swash standstill time is advocated as a valuable part of the swash exclusion hypothesis. A survey of the available literature on the burrowing of surfers shows that mole crabs are by far the fastest burrowers and the only surfers that burrow sufficiently fast to withstand the extremely short swash standstill time on reflective beaches. Burrowing ability of surfing gastropods is found in the same range as surfing bivalves, both being insufficient to cope with coarse sediment on steep beaches. Finally, we suggest that neither burial time nor BRI, yet rather the minimal burial time—the time needed to anchor securely in a certain sand at a given swash velocity—should be used to judge the limitations of burial in terms of sediment and swash conditions.
KeywordsBeach Shell Length Sandy Beach Swash Zone Burial Time
The authors wish to thank three anonymous reviewers for their useful suggestions and comments. The first author and the field campaign were financially supported by a research assistant grant from the Fund for Scientific Research Flanders (Belgium). Additional financial support for the field work was provided by the Leopold III fund. We thank Ann Merckx, Lien Steenhuyse, Danielle Schram and Galo Chancay for their help with the data collection and help in the lab. The Escuela Superior Politecnica del Litoral ESPOL, Guayaquil (Ecuador) and the Centro Nacional de Acuicultura e Investigaciones Marinas CENAIM, San Pedro (Ecuador) are acknowledged for their logistic support.
- Aerts K, Vanagt T, Fockedey N et al (2004) Macrofaunal community structure and zonation of an Ecuadorian sandy beach (bay of Valdivia). Belg J Zool 134(1):17–24Google Scholar
- Brown A, McLachlan A (1990) Ecology of Sandy Shores. Elsevier, AmsterdamGoogle Scholar
- Buchanan J (1984) Sediment analysis. In: Holme NA, McIntyre AD (eds) Methods for the study of marine benthos. Blackwell Scientific Publications, Oxford, pp 41–65Google Scholar
- Defeo O (1996) Experimental management of an exploited sandy beach bivalve population. Rev Chil Hist Nat 69:605–614Google Scholar
- Dudley E, Vermeij G (1989) Shell form and burrowing performance in gastropods from Pacific Panama, with comments on regional differences in functional specialization. Veliger 32(3):284–287Google Scholar
- Dugan J, Hubbard D, Lastra M (2000) Burrowing abilities and swash behavior of three crabs, Emerita analoga Stimpson, Blepharipoda occidentalis Randall, and Lepidopa californica Efford (Anomura, Hippidae), of exposed sandy beaches. J Exp Mar Biol Ecol 255:229–245. doi: 10.1016/S0022-0981(00)00294-X CrossRefGoogle Scholar
- McArdle S, McLachlan S (1992) Sandy beach ecology: swash features relevant to the macrofauna. J Coast Res 8:398–407Google Scholar
- McLachlan A (1990) Dissipative beaches and macrofauna communities on exposed intertidal sands. J Coast Res 6:57–71Google Scholar
- McLachlan A, Brown A (2006) The ecology of sandy shores, 2nd edn. Elsevier, AmsterdamGoogle Scholar
- McLachlan A, Jaramillo E, Donn T, Wessels F (1993) Sandy beach macrofauna communities and their control by the physical environment: a geographical comparison. J Coast Res 81(15):27–38Google Scholar
- Olsson A (1956) Studies on the genus Olivella. Proc Acad Nat Sci Philadelphia 108:155–225Google Scholar
- Short A (1999) Handbook of beach and shoreface morphodynamics. Wiley, Chichester 373 ppGoogle Scholar
- Vanagt T (2007) The role of swash in the ecology of Ecuadorian sandy beach macrofauna, with special reference to the surfing gastropod Olivella semistriata. PhD Thesis, Ghent University, BelgiumGoogle Scholar
- Vermeij G, Zipser E (1986) Burrowing performance of some tropical pacific gastropods. Veliger 29(2):200–206Google Scholar