PARENT SESSION
Contributed Oral Session 69: Marine Ecology: Habitat; Communities
Tuesday, August 9, 1:30 PM - 5:00 PM, Meeting Room 522 A, Level 5, Palais des congrès de Montréal

Linking fish assemblages to marine landscape structure at multiple spatial scales.

Pittman, Simon^*,1, Shapiro, Aurelie¹, Caldow, Chris¹, Monaco, Mark¹, ¹ NOAA/NOS/CCMA Biogeography Program, Silver Spring, Maryland, USA

ABSTRACT- Coral reef ecosystems exhibit complex spatial and temporal patterns in biophysical structure. These patterns vary in heterogeneity within scale and between scales and are likely to influence the way that animals use their environment and also may be indicative of broader ecological processes, including human activity. Many studies in marine environments have linked high spatial heterogeneity within habitats to high fish species diversity at relatively fine scales, yet few studies have examined these relationships at multiple spatial scales, that also encompass multiple habitat types. In order to characterize fish-habitat linkages at multiple spatial scales, the Biogeography Team of the National Oceanic and Atmospheric Administration (NOAA) have mapped, classified and quantified benthic habitats of the La Parguera region in southwest Puerto Rico and have surveyed fish across the coastal shelf at more than 650 sites over four years, including coral reefs, seagrasses and mangroves. Results indicated that habitat type, more than cross-shelf location, influenced fish spatial patterns and species size class distributions. Building on this, we then examined the statistical relationships between fish assemblage attributes and the spatial patterns in habitat types, including the surrounding marine landscape structure. Landscape structure was quantified using a range of pattern metrics applied to thematic maps, as well as, a range of spatial statistics applied to Landsat Enhanced Thematic Mapper (ETM+) imagery, including the Getis statistic for quantifying spatial heterogeneity. In addition, change in structural heterogeneity at multiple spatial scales was analyzed for a time series (1989-2003) of Landsat Thematic Mapper (TM) and ETM+ imagery. Hotspots of change in benthic structure were identified from satellite imagery in approximately 10% of the study area, and were identified as either expansion of submerged aquatic vegetation in backreef and shelf areas, or sedimentation in lagoonal habitats closer to shore. The ability to identify and quantify fish-habitat relationships at appropriate spatial and temporal scales will contribute to both the understanding of coral reef ecosystems and support resource management.

Key words: spatial heterogeneity, marine landscape ecology, coral reef fish, spatial statistics