2.3. Epifauna Sampling
To assess the influence of plant structure on epifaunal diversity and determine if different morphologically distinct seagrass populations supported varied epibenthic diversities, invertebrate fauna present in both the seagrass canopy and sediment surface was estimated. A visual census method was employed to quantify the densities of epifauna within quadrats (50 cm x 100 cm) targeting a size fraction >3 mm. The surveys were conducted during spring low tide when the seagrass beds were fully exposed. This method allowed for the quantification of a subset of seagrass-associated fauna, primarily focusing on invertebrates that graze on seagrass leaves and epiphyton and differs from traditional techniques used to quantify infauna i.e., digging and sieving sediments (Edgar et al., 2001). Traditional methods are more suitable for evaluating a general suite of fauna associated with both seagrasses and unvegetated habitats, which even if sampled collectively is often analysed separately to answer specific questions ((Rodil et al., 2021).
Five quadrats were randomly placed within each seagrass bed at each of the five sites across four seasons (n = 420). Within each quadrat, all visible fauna present on, among, and below the seagrass leaves were identified and counted. If any specimen could not be identified on-site, they were collected for later identification. Species were then categorised into phyla and functional groups using guidebooks (e.g. (Branch, 2017) and the World Register of Marine Species (www.marinespecies.org).