|Life history variation in the intertidal snail Nucella lapillus across a wave-exposure gradient|Etter, R.J. (1989). Life history variation in the intertidal snail Nucella lapillus across a wave-exposure gradient. Ecology 70(6): 1857-1876
In: Ecology. Ecological Society of America: Brooklyn, NY. ISSN 0012-9658, more
Nucella lapillus (Linnaeus, 1758) [WoRMS]; Marine
demography; growth rates; life history variation; Massachusetts coast; mortality rates; Nucella lapillus; population dynamics; reproductive ecology; wave exposure
Demographic and life history characteristics of the intertidal whelk Nucella lapillus were measured across a wave-exposure gradient to quantify the variation in, and identify the ecological forces shaping, each trait. Growth rates, survivorship, size and age at maturity, fecundity, and per-offspring parental investment were estimated from marked snails during a 3-yr period. Growth rates as indicated by changes in shell length, total mass, shell mass, and body mass varied among populations from different exposure regimes. Relative to more protected sites, snails from exposed shores grew more slowly and terminated growth at a smaller size. Age at maturity did not differ between whelks from high- and low-wave-energy populations, but those on the exposed shore matured at a smaller size. Mortality rates increased with wave energy. Size-specific mortality rates indicated that the higher mortality on wave-swept shores reflected decreased survivorship of large (@> 15 mm) adults relative to similar sized individuals on more protected shores. Exposed shore snails deposited twice as many egg capsules with twice as many hatchlings emerging from each capsule. Although the hatchlings were @?25% smaller, four times as many were produced, suggesting that reproductive effort was considerably greater on exposed coasts, offsetting the higher mortality rates. The ecological forces (energetic, physiological, abiotic, etc.) potentially responsible for the life history variation among populations from different wave-exposure regimes are discussed.