Document: HUN-3-10-7

How heterogeneity at different spatial scales controls community composition and dynamics in restored estuarine habitats.

LENIHAN, H.

UNC-Chapel Hill, Morehead City, NC 28557 USA ¹

Abstract:
Habitat heterogeneity at different spatial scales is likely to significantly influence community structure and dynamics in different ways. Understanding how various habitat types distributed across seascapes in different combinations influences associated species is fundamental to conserving and restoring exploited marine populations. I tested how species richness and predatory-prey interactions among estuarine fish assemblages and benthic invertebrate prey varied with changes in small-scale structural complexity and large-scale seascape heterogeneity. Restored estuarine habitats of varying structural complexity (oyster reefs, artificial reefs, and seagrass beds) were placed in different spatial combinations (i.e, varying degrees of seascape heterogeneity: single habitats, paired habitats, and in triplet combination) within a North Carolina estuary and sampled for the abundance of fish and benthic crustacean populations through time using various sampling methods. Both habitat and seascape complexity had strong influences on species richness and the intensity of predation. The species richness of both fish (predators) and invertebrate prey increased with habitat and seascape heterogeneity. In contrast, the total abundance of most predators decreased with habitat heterogeneity apparently in response to variation in prey density that was driven by a few key predators and variable recruitment. The total abundance of most fishes was greatest at the highest level of seascape heterogeneity. Results from this experiment indicate that increasing the heterogeneity of restored habitat at different spatial scales is likely to have important impacts on communities composition and dynamics of exploited marine species.

Keywords: seascape heterogeneity, species richness and abundance, habitat resoration, estuarine fishes

This abstract is being presented at: 4:00 PM in session:
Oral Session #65: Wetlands, Estuaries and Salt Marshes.