AbstractsBiology & Animal Science

The Influence of Habitat and Conspecific Adults on the Abundance and Spatial Distribution of Juvenile Corals

by Nicole Elizabeth Pedersen

Institution: University of California – San Diego
Year: 2016
Keywords: Ecology; clustering; coral reef; Palmyra Atoll; photomosaic; spatial patterns
Posted: 02/05/2017
Record ID: 2134313
Full text PDF: http://www.escholarship.org/uc/item/7rj858zg


Population distributions are driven by a variety of spatial processes, including dispersal, competitive dynamics, and resource availability. Within coral communities, these processes may influence patterns of settlement or mortality, which are highest amongst early life stages. Understanding how individuals are distributed can provide insight into how these communities are structured. Here, we use large area photomosaic images created by stitching together thousands of individual images to examine how early life stage dynamics operate on broad spatial scales. At eight sites on the forereef of Palmyra Atoll, photomosaics (100 m2 in size) were collected and used to identify and map all juvenile (<5 cm diameter) and adult coral colonies. Using metrics of density, percent cover, and the position of each colony, we examined abundance and spatial relationships between juvenile and adult populations. Our results show that juvenile density is more strongly related to the numerical density of adults rather than percent cover. Additionally, we found that juveniles of some taxa were associated with specific habitat types, most often favoring unconsolidated over consolidated substrata. Nearest neighbor analyses showed conspecific aggregation of juveniles with respect to adults for two of the focal taxa, while all other taxa were randomly distributed around adults. However, juveniles for five of the eight taxa had clumped distributions, suggesting that environmental factors such as habitat type rather than intraspecific associations have a greater influence on spatial distributions at the juvenile stage. Using spatial patterns, we examine how reproduction and local benthic characteristics structure early life stage coral populations.