Abiotic surrogates for temperate rocky reef biodiversity: implications for marine protected areas

Abstract

Aim To examine the potential of remotely sensed abiotic measures as surrogates for the abundance, diversity and community composition of temperate rocky reef fishes and sessile invertebrates. Location Batemans Marine Park, south‐eastern Australia. Methods We used high‐resolution bathymetric side‐scan sonar imagery to quantify abiotic measures of rocky reef habitat, within a marine protected area (MPA), and examine the relationship between abiotic measures and (1) sessile invertebrate abundance, (2) sessile invertebrate species richness, (3) total fish abundance, (4) fish species richness, and (5) Monacanthidae abundance using generalized additive mixed models (GAMMs). We chose GAMMs as the preferred statistical analysis to account for the spatial autocorrelation present in our data. Results We found a strong positive relationship between abiotic measures and sessile invertebrate abundance and diversity (r2 > 0.64). By far the most important predictor was vertical relief within a 75 m radii seascape surrounding the faunal survey. Overall, abiotic measures were poor predictors of total fish abundance (r2 = 0.175) and fish species richness (r2 = 0.276), with minimum adequate models producing low explanatory power. In contrast, Monacanthids exhibited a strong positive relationship with abiotic variables (r2 = 0.385), with increased abundance associated with greater depth and distance from soft sediment. Main conclusions Remotely sensed abiotic measures are important predictors in describing the spatial patterns of sessile invertebrate abundance and diversity and Monacanthid abundance. In contrast, abiotic variables were poor predictors of total fish abundance and diversity. Habitat could be a useful cost‐effective surrogate to determine areas of conservation value for certain temperate rocky reef assemblages. This information is valuable for future MPA development and design.

Application of species distribution models to explain and predict the distribution, abundance and assemblage structure of nearshore temperate reef fishes

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Habitat structural complexity metrics improve predictions of fish abundance and distribution

“…In marine ecosystems fish abundance is strongly related to benthic biota and depth (Osmundson et al 2002, Chong-Seng et al 2012, Fitzpatrick et al 2012). Yet, precisely measured estimates of habitat structural complexity have only recently been explored as a potential surrogate of fish abundance and richness (Rees et al 2014). Although airborne laser-scanning and aerial images are used to obtain high-resolution 3D metrics of complexity on land (Goetz et al 2010, Zellweger et al 2013, Eldegard et al 2014, repeatable and high-resolution measurement of complexity in marine and freshwater systems has proven difficult (Graham and Nash 2013).…”

Forests of the sea: Predictive habitat modelling to assess the abundance of canopy forming kelp forests on temperate reefs

“…In the marine environment, where it is difficult to intensively sample over large areas, SDMs are extremely useful for understanding species distributions across landscapes (Elith & Leathwick, 2009). Mapping out the spatial distributions of marine species can help with coastal management (Margules & Pressey, 2000;Jordan, Lawler, & Halley, 2005;Ross & Howell, 2012;Rees, Jordan, Price, Coleman, & Davis, 2014), inform ecological studies (Duarte, 1999), and quantify biodiversity in marine systems (Gray, 2001;Fernandes et al, 2005;Rees et al, 2014).…”