1. Spatial variability in community structure of Dictyoceratid sponges across Torres Strait, Australia Alan Duckworth, Carsten Wolff, Elizabeth Evans- Illidge, Stephan Whalan and Stanley Lui Australian Institute of Marine Science Torres Strait Regional Authority CRC Torres Strait

2. Four locations, 50 to 220 km apart

3. Survey methods At each location, 5-7 sites,  2 km apart At each location, 5-7 sites,  2 km apart At each site, 4 x 100 m 2 transects, 5-15 m deep on reef At each site, 4 x 100 m 2 transects, 5-15 m deep on reef Record every dictyoceratid sponge Record every dictyoceratid sponge Record environmental factors: substrate type and slope, visibility Record environmental factors: substrate type and slope, visibility

4. 25 dictyoceratid species, known and unknown Dysidea herbacea Coscinoderma sp. Carteriospongia flabellifera Phyllospongia papyraceaPhyllospongia lamellosa Hyrtios reticulata Dysidea sp. 3Ircinia sp. 4 Ircinia ramosa

5. Species Richness No dictyoceratid species found at all four locations No dictyoceratid species found at all four locations 12 of 25 species found at only one location 12 of 25 species found at only one location Richness among locations: P=0.02

6. Mean abundance of all dictyoceratid sponges

8. Dendrogram showing similarity of dictyoceratid communities among sites B=Badu T=Thursday Y=Yorke D=Darnley Numbers=sites 7 clusters, sites similar… within a location between neighbouring locations between locations 100’s km apart

9. CCA plot showing distribution to environmental factors Distribution and abundance patterns only partially explained by environmental factors

10. Environmental factors Among locations rock varied, highest at Darnley and Yorke rubble varied, highest at Badu and Thursday sand similar Reef slope, survey depth and water visibility also similar Among sites(locations) Rock, rubble, sand, slope, depth and visibility all varied

11. Conclusions Abundance patterns can vary greatly between neighbouring sites Abundance patterns can vary greatly between neighbouring sites Species richness can vary greatly between neighbouring locations Species richness can vary greatly between neighbouring locations Complex dictyoceratid community structure Complex dictyoceratid community structure Similar patterns between neighbouring sites and among sites 100’s km apart Similar patterns between neighbouring sites and among sites 100’s km apart Great variation between neighbouring sites 2 km apart Great variation between neighbouring sites 2 km apart Measured environmental factors only partially explain distribution patterns Measured environmental factors only partially explain distribution patterns Spatial variation of dictyoceratid sponges in Torres Strait influenced by a combination of environmental, biological and stochastic processes Spatial variation of dictyoceratid sponges in Torres Strait influenced by a combination of environmental, biological and stochastic processes