Pre- and post-settlement events in benthic community dynamics

Abstract

In all marine benthic environments, organism replacement depends on recruitment limitation, i.e. the impact of both pre-and post-settlement events on the success of recruitment. The relative contribution of pre-versus post-settlement processes in shaping adult populations has been extensively studied. Most analyses concluded that recruitment limitation is a strong determinant of adults' density. The magnitude of its limitation depends on context, varies with species, and can be strongly modified by all the events preceding and following recruitment itself. A comparison of the outcome of recruitment limitation on hard-and soft-bottom communities has often been neglected. The rules governing these two environments, in both the inter-and the subtidal, might be inferred only by comparing and possibly integrating soft-and hard-bottom ecologies. The highly variable situation that larvae face in the water column is followed by the variability linked to local features, influencing, in its turn, larval settlement and juvenile survival (post-settlement period). A better knowledge of these processes will be possible only by focusing on their relative importance in the two environments and with research on the brief but significant time of larval settlement.

Effects of sea stars and crabs on sea scallop Placopecten magellanicus recruitment inthe Mid-Atlantic Bight (USA)

“…However, recruitment remained low at depth extremes during this period. Moreover, the relationships observed here were consistent over the 3 yr period, whereas larval settlement patterns tend to be highly variable (Fraschetti et al 2003). These considerations suggest that larval supply is not responsible for the observed distribution of sea scallop recruitment with depth.…”

“…Yet, despite intensive study, there is still limited understanding of the factors that determine the spatio-temporal patterns of recruitment (Ólafsson et al 1994, Gosselin & Qian 1997, Hunt & Scheibling 1997, Fraschetti et al 2003. While the supply of larvae can influence the level of recruitment, much variation in recruitment cannot usually be explained by this factor.…”

Seasonal changes of planktonic polychaete larvae and chlorophyll a concentration in Onagawa Bay, northeastern Japan

“…In most sessile and benthic organisms having little mobility, except some migratory species, the planktonic larval phase represents an important opportunity to acquire new habitats and to cross with other populations. Variability in recruitment is potentially important for the dynamics and structure of populations and communities (Caley et al 1996;Fraschetti et al 2002). However, little is known about the seasonal and spatial change in abundance of most invertebrate larvae, as abundance depends on the reproductive timing of the adults, the duration and behavior of the larvae, and ocean circulation patterns.…”

Acoplamento Plâncton-Bentos: O Papel Do Suprimento Larval Na Estrutura Das Comunidades Bentônicas De Costões Rochosos

“…São aqueles eventos que alteram o suprimento de larvas na coluna de água. Fraschetti et al 2003 Eventos pós-assentamento Processos que acontecem uma vez que a larva tenha se fi xado defi nitivamente ao substrato. Inclui interações com conspecifi cos (estímulos químicos, interferência, competição), com outras espécies (predação, competição, facilitação) ou com fatores físicos (fl uxo d'água) até o indivíduo ser considerado recruta (neste estudo, após 24 horas).…”

“…Revisões sobre ESL foram realizadas por Underwood & Fairweather (1989), Underwood & Keough (2001), Fraschetti et al (2003) e Levin (2006). Estes autores focaram diferentes aspectos tais como: as conseqüências de variações do recrutamento em comunidades bentônicas marinhas, em especial de regiões de entremarés, diferenças entre comunidades de substrato consolidado e não consolidado e dispersão das larvas, respectivamente.…”