Larval supply and recruitment of benthic invertebrates: do larvae always disperse as much as we believe?

摘要: The concept of larval supply, and the relative importance pre- post-settlement processes as structuring agents marine benthic invertebrate assemblages communities are discussed. Because pelagic larvae result in an essential decoupling local reproduction from recruitment, many populations should be considered demographically ‘open’. Accordingly, factors affecting input to benthos might especially important both communities, even supercede such competition, predation physical disturbance. Comprehensive studies on intertidal barnacles have provided initial focus for field studies, but perhaps greatest challenge facing ecologists lies extrapolating beyond single-species assess whole or communities. Amongst rocky assemblages, supply do appear circumstances where recruitment levels low: at higher levels, prominent. No comprehensive evaluation has been undertaken soft sediment prevailing consensus is that hydrodynamic factors, density dependent effects food availability prime importance. For epifaunal ‘fouling’ probably very important, illustrative data presented show post-recruitment may mask strong signals later assemblage development. Short-term panel showed hard substratum not necessarily conform simple measures current velocity a given site: application tidal flushing model did, however, assist explaining variation rates relation water flux below arbitrary critical settlement. An indirect means assessing realized dispersal – hence geographic scale population ‘openness’ available analyses genetic differentiation. Data two species molluscs with contrasting types. planktotrophic conformed expectations, showing homogeneity over 1600 km range, therefore displaying large-scale dispersal. lecithotrophic species, revealed differentiation small scales (< 10 km), highly dispersive environments currents (up 3.6 m s-1). deduction contrary actually facilitating dispersal, those behaviourally constrained minimize transport. consequences this general deductions about discussed, knowledge spatial domination there attributable largely three phyla which characteristically reproduce by short-term stages.