International Journal of Marine Science, 2016, Vol.6, No.21, 1-20
14
cover remaining throughout the FKNMS regardless of the more consistent environment associated with offshore
reefs. We observed a greater percentage of live coral cover and greater coral diversity at five sites within the
inshore reef system spanning the lower and middle keys compared to five bank reef sites. Community level
analysis of an inshore and offshore reef site, further support that scleractinian corals inhabiting inshore sites are
not only more abundant (Figure 2) and more diverse (Figure 3), but mean colony size is significantly greater
(Figure 7). Although the rapid loss of dominant acroporid corals from the bank reef system caused a dramatic shift
in reef biota (Patterson et al., 2002) as a consequence of the epizootic pathogen
Serratia marsescens
(Patterson et
al., 2002; Sutherland et al., 2011), this event alone does not explain the failure of the currently dominant coral
species (Burman et al., 2012) to re-establish this zone over the past 20 years given the apparent absence of other
potential environmental constraints.
Figure 10. Frequency of occurrence for three brightness states following a reciprocal transplant of
P. astreoides
and
M. cavernosa
.
Three bins were created for mean brightness values, each spanning approximately 40 units. The four graphs are separated along the
y-axis by the site to which a coral was transplanted. Bar color indicates collection site (Black = Acer 24, Grey = Birthday). The
graphs are further separated by species along the x-axis. Bar height is indicative of the cumulative number of occurrences within a
particular bin from monthly images taken from September 2011-April 2013.
Our analysis indicates that inshore and offshore reefs of similar depth (6 m) within the middle and lower FKNMS
support distinct scleractinian coral communities. The abundances of four species greatly influenced the ordination
of inshore sites away from offshore sites;
Acropora palmata
,
S. siderea
,
M. cavernosa
, and
P. astreoides
(Figure
4). The influence of
A. palmata
was least revelatory as this known specialist inhabits a narrow habitat range
including high relief and inner line spur and groove habitats found only in the offshore reef zone (Miller et al.,
2008). The current endangered status of
A. palmata
also precluded it’s inclusion in our transplant study.
Siderastrea siderea
, the most common scleractinian coral currently inhabiting the FKNMS (Burman et al., 2012),
was highly prevalent regardless of the zone. Because the goal of this study was to identify sources of variation in
the coral cover of inshore and offshore sites, the known generalist nature of
S. siderea
(Burman et al., 2012)
precluded this species as well. The remaining two species,
P. astreoides
and
M. cavernosa
, although considered
eurytopic (Burman et al., 2012), inhabited inshore and offshore zones with differing degrees of prevalence
