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).