Species Richness and Community Structure on a High Latitude Reef: Implications for Conservation and Management

Abstract

Abstract:In spite of the wealth of research on the Great Barrier Reef, few detailed biodiversity assessments of its inshore coral communities have been conducted. Effective conservation and management of marine ecosystems begins with fine-scale biophysical assessments focused on diversity and the architectural species that build the structural framework of the reef. In this study, we investigate key coral diversity and environmental attributes of an inshore reef system surrounding the Keppel Bay Islands near Rockhampton in Central Queensland, Australia, and assess their implications for conservation and management. The Keppels has much higher coral diversity than previously found. The average species richness for the 19 study sites was ~40 with representatives from 68% of the ~244 species previously described for the southern Great Barrier Reef. Using scleractinian coral species richness, taxonomic distinctiveness and coral cover as the main criteria, we found that five out of 19 sites had particularly high conservation value. A further site was also considered to be of relatively high value. Corals at this site were taxonomically distinct from the others (representatives of two families were found here but not at other sites) and a wide range of functionally diverse taxa were present. This site was associated with more stressful conditions such as high temperatures and turbidity. Highly diverse coral communities or biodiversity 'hotspots' and taxonomically distinct reefs may act as insurance policies for climatic disturbance, much like Noah's Arks for reefs. While improving water quality and limiting anthropogenic impacts are clearly important OPEN ACCESSDiversity 2011, 3 330 management initiatives to improve the long-term outlook for inshore reefs, identifying, mapping and protecting these coastal 'refugia' may be the key for ensuring their regeneration against catastrophic climatic disturbance in the meantime.

A U‐Th Dating Approach to Understanding Past Coral Reef Dynamics and Geomorphological Constraints on Future Reef Growth Potential; Mazie Bay, Southern Great Barrier Reef

“…The period 1998 to 2010 is defined predominantly by thermal bleaching in the earlier years and flooding of the Fitzroy River in the later years (Figures and S6; Berkelmans et al, ; Elvidge et al, ). While coral bleaching was observed in 1998 and 2002, post bleaching assessments reported little total coral mortality in the Keppel Islands (Jones et al, ; Maynard et al, ; van Oppen et al, ). The lack of death assemblage dating to this period supports observations that corals were able to recover from bleaching via tissue regeneration (Diaz‐Pulido et al, ), with little destruction of the original framework.…”

“…The modern reef slope drops rapidly to a sandy base at a depth of 7 mLAT and is dominated by fast growing arborescent Acropora spp. with generally high coral cover (~60%); however, the region experiences frequent disturbance events that periodically affect coral cover dynamics (Jones et al, 2011;Kennedy et al, 2018;van Woesik & Done, 1997). Notable recent disturbance 10.1029/2019PA003768 Paleoceanography and Paleoclimatology events include up to 100% coral mortality due to flooding in 1991 ( Van Woesik, 1991) andsubstantial thermal bleaching in 1998substantial thermal bleaching in , 2002substantial thermal bleaching in (Elvidge et al, 2004, and 2006; mild to moderate bleaching in 2016 (Kennedy et al, 2018); and observed cyclone damage in 1976 and 2015.…”

“…Stochastic disturbance regimes have affected coral reefs over geological timescales, yet it remains uncertain as to whether current global declines in reef growth are unprecedented, and whether reefs have lost their ability to recover due to increasing anthropogenic pressures (Clark et al, ; Clark et al, ; Hughes et al, ; Jones et al, ; Williamson et al, ). It is therefore important to evaluate modern reef growth against long‐term reef dynamics to understand the historical development of reefs relative to geomorphological constraints, as well as to determine past reef response to climatic and environmental change at various temporal scales (van Woesik & Done, ).…”

“…Located in the Southern inshore GBR (Figure ), the Keppel Islands reefs were thought to have only initiated in the past 1,500 years (Jones et al, ). However, recent U‐Th dating of coral microatoll and emergent reef flat coral from North Keppel, Great Keppel, and Humpy Islands indicates that reef flats had developed in the region by ~6,900 yr. BP and, similar to the synthesis of Perry and Smithers (), showed a potential reef hiatus between 4,600 and 2,800 yr. BP (Leonard et al, ).…”

Raiding the Coral Nurseries?

“…Regardless of the cause, the risk is that without timely and prolonged restrictions on harvest there could be a risk of further population declines. Since these species are already sparse and occur in small, isolated populations in the first place [35,57] there could be an "Allee" effect on the capacity of such a small population to regenerate [58,59].…”