Range-extending tropical herbivores increase diversity, intensity and extent of herbivory functions in temperate marine ecosystems
Zarco-Perello, Salvador; Wernberg, Thomas (2020), Range-extending tropical herbivores increase diversity, intensity and extent of herbivory functions in temperate marine ecosystems, Dryad, Dataset, https://doi.org/10.5061/dryad.8w9ghx3hx
Surveys of herbivorous fish were conducted over inshore habitats along the coastline of south-western Australia during summer (April-May) of 2018 and 2019, from the Perth metropolitan area to Cape Naturaliste in the south of the state. The abundances of temperate (Girella zebra, Olisthops cyanomelas, Pelates octolineatus, Kyphosus cornelii and Kyphosus sydneyanus) and tropical herbivorous fish (Scarus spp. and Siganus fuscescens) were measured via a GPS-tracked roving underwater visual census with 15 minutes per sampling location. One surveyor swam at a constant pace, registering all individuals of the species of interest in an approximate area of 2000 m2 per transect. A second surveyor followed the same path recording the seascape with an underwater camera for subsequent assessment of habitat features. Videos were analyzed with the program TransectMeasure (SeaGIS), each video transect was paused at one minute intervals (n=15 per transect) to extract information on topographic complexity (Wilson, Graham & Polunin 2007), substrate type, species composition, species diversity, and abundance of morpho-functional groups of sessile biota based on the CATAMI classification scheme (Althaus et al. 2015). Fish abundance was standardized to density (individuals 125 m-2); however, we also considered a new metric: MaxS (maximum number of fish per school in each survey), a similar approach to abundance assessments of pelagic schooling fish (i.e. school size; Beare 2002) and abundance estimates from static video methods (i.e. MaxN; Cappo et al. 2003).
The Holsworth Wildlife Research Endowment & The Ecological Society of Australia, Award: RA/1/411/101