LIFE-CYCLE AND LIFE-HISTORY DIVERSITY IN MARINE-INVERTEBRATES AND THE IMPLICATIONS IN COMMUNITY DYNAMICS

The increased interest in autoecology in order to understand better complex ecological systems, implies the need for a deeper knowledge of life-cycle and life-history traits. The ecological relevance of different developmental patterns is still a matter of debate. Advantages can be summarized as differential rates of resource utilization, reproductive effort, and dispersal, considering the energy investment per egg, and mortality compared with the length of pelagic life. The existence of pelagic stages in the cycle of benthic organisms may be seen as a migration into a different trophic compartment, and dispersal may be interpreted as a by-product. Reproductive traits are varied and differ even within the same taxonomic group. Scant knowledge on marine invertebrate life cycles prevents broad generalizations. Also the covariability of life-history traits and phylogenetical and morpho-functional constraints further complicate the observed patterns. Demographic aspects have implications in community dynamics, especially considering larval and juvenile mortality compared with successful recruitment. Community structure is controlled by larval supply, settlement success, and larval transport mechanisms acting at a considered site. These components, as well as the presence of resting stages in the life cycle, are of great importance in explaining species fluctuations in space and time.