International Journal of Marine Science, 2016, Vol.6, No.21, 1-20
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the mean benthos cover resulted in a single species difference between inshore and offshore reefs. Rényi profiles
of coral abundance indicated that all sites were dominated by a few species and therefore, are characterized by low
species evenness (Figure 3). The most speciose sites, Looe Key from offshore reefs and Western Head from
inshore reefs, displayed the least evenness. Offshore sites other than Looe Key reef, displayed similar profiles,
indicated by the similar slopes of Rényi profiles. Although inshore sites displayed similar species richness,
diversity profiles of sites within this zone indicate within zone community variation. Dustan Rocks and Western
Washerwoman were the most similar of the inshore sites while Cliff Green with very similar richness to these two
sites, was less even.
Figure 3. Mean Rényi diversity profiles of CREMP and established patch and offshore reef sites. Patch reef points (grey triangles)
and offshore points (black circles) are identified similarly for CREMP data (A) and established sites (B). CREMP data points reflect
the mean value at each location across the sampling period from 1996-2011, while points for established sites reflect mean Rényi
values of transects carried out in the summer and winter of 2012 (n=6 per site). Loess regression was applied to visualize each trend
(grey line = offshore reefs, black line=inshore patch reefs). Alphas at 0, 1, and Inf indicate species richness, community diversity
weighting all species equally, and community diversity with greater weight placed on more abundant species, respectively.
Zonal ordination of coral communities was identified following PCoA (Figure 4). Inshore sites ordinated closely
together in quadrant 3 while offshore reefs, although displaying more variability, ordinated in the periphery away
from this cluster in quadrants 1, 2, and 4, centering on quadrant 2 (Figure 4). Evaluating the loadings, along the
first two axes, the abundances of some coral species were dissimilar between locations. Inshore patch reefs were
characterized by an increased prevalence of
M. cavernosa
and
Sidereastrea siderea
, while
P. astreoides
and
Acropora palamata
were more common at offshore bank reefs.
Analysis of CREMP data supports the ongoing observation of increased abundance of corals at inshore patch reefs,
however the CREMP data set is limited to relative abundance. To circumvent this issue we selected two reference
sites within each zone to analyze in greater detail, focusing on coral community characteristics, particularly
colony abundance, colony size, and benthic community composition. The mean seasonal benthos composition at
