Ecological scaling in mangroves: The role of microhabitats for the distribution of larval assemblages

Abstract

Mangroves are regarded as important spawning and settlement grounds as well as nurseries for larvae and juvenile fishes and invertebrates due to the sheltered nature of these ecosystems. The present study examined the spatial and temporal distribution of fish and invertebrate larvae, simultaneously among several microhabitats, within two South African mangrove forests. Results indicate that despite temperature and salinity homogeneity across microhabitats, spatio-temporal differences occurred in both fish and invertebrate larval assemblages. The distinct larval assemblages were driven by the site-specific predisposition of taxa to occur more abundantly in one or more specific microhabitats, while temperature, salinity and tidal phase temporally structured both invertebrate and fish larval communities. The larvae of estuarine dependent marine fish occurred in mangrove microhabitats, suggesting they use structural mangrove patchiness as corridors or temporary nurseries before settling in situ, into their juvenile habitat. This study steers that the proposed nursery function or early stage role that mangroves play is driven by the structural uniqueness of mangrove microhabitats thus ensuring localised ecological linkages and functionality of these critical coastal environments.