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Publication year : 0
Thematic : Environmental Education
Language : English
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Coral reefs of the Turks and Caicos Islands (TCIs) constitute some of the few
pristine coral reef systems in the world and play a crucial role in the islands’
economy because they support rich fisheries catches and tourism development.
Ambitious development plans involving increase in fishing and tourism pressures
are about to bring changes in coastal zone resources of the TCIs associated
with increased sediments and nutrients and reduced predation by
herbivorous fish on coral reefs. Understanding change is critical when attempting
to protect the resources that these coral reefs support and to adopt proper
management strategies. Yet, an environmental assessment program to detect
imminent human-induced changes on the surrounding reefs of the TCIs is
lacking. Thus, (i) we obtained baseline data on benthic composition and coral
community structure at seven reef sites of representative reefs of the TCIs
within the Admiral Cockburn Land and Sea National Park (ACLSNP) of South
Caicos Island and (ii) performed a priori statistical power analysis to calculate
replication requirements for safely and confidently detecting small (d = 0.1),
medium (d = 0.3), and large (d = 0.5) effect sizes for a number of relevant to
anticipated changes, univariate, benthic indices and for power b = 0.95. The
platforms of the margin reefs studied (9–12 m depth) appeared rather variable
regarding benthic composition but quite homogeneous regarding hard coral
community structure. Mean percent cover of algal functional groups was
0.1 ± 0.3 (mean ± sd) percent for coralline algae and Halimeda, 0.1 ± 0.6
(mean ± sd) percent for macroalgae, 21.7 ± 33 (mean ± sd) percent for turf
algae and 4.8 ± 4.0 (mean ± sd) percent for hard coral cover. The dominant benthic
component, however, was carbonate substrate (mean ± sd = 30.4 ± 34.3),
thus indicating an accreting reef framework. Mean hard coral density, colony size
and recruit density were 5.5 ± 1.8 (mean ± sd) corals per 20-m line transect,
13.0 ± 2.3 (mean ± sd) cm maximum colony diameter, and 1.3 ± 1.4
(mean ± sd) recruits per square foot, respectively. Due to high natural variance,
hard coral colony size and density were practically the most sensitive indices in
detecting even small size changes on benthos. Also, the geometric mean of
log-transformed colony size-frequency distributions of the most abundant hard
coral taxa, i.e. Montastrea annularis, Agaricia spp., Siderastrea spp. and Porites
asteroides were practically sensitive for the same purpose. We hope that the study
will optimize the spatial component of a necessary environmental impact assessment
program on coral reefs of the TCIs once the natural spatial variability of
the system has been assessed and sensitive, benthic, univariate indices have been
identified for representative reference coral reef sites of the TCIs.
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Keywords : Pseudorabdion oxycephalum
Encoded by : Pauline Carmel Joy Eje
