Michelle Linklater

Response of coral reefs to climate change: Expansion and demise of the southernmost Pacific coral reef

Received 21 May 2010; revised 20 June 2010; accepted 6 July 2010; published 3 August 2010. [1] Coral reefs track sea level and are particularly sensitive to changes in climate. Reefs are threatened by global warming, with many experiencing increased coral bleaching. Warmer sea surface temperatures might enable reef expansion into mid latitudes. Here we report multibeam sonar and coring that reveal an extensive relict coral reef around Lord Howe Island, which is fringed by the southernmost reef in the Pacific Ocean. The relict reef, in water depths of 25–50 m, flourished in early Holocene and covered an area more than 20 times larger than the modern reef. Radiocarbon and uranium‐series dating indicates that corals grew between 9000 and 7000 years ago. The reef was subsequently drowned, and backstepped to its modern limited extent. This relict reef, with localised re‐establishment of corals in the past three millennia, could become a substrate for reef expansion in response to warmer temperatures, anticipated later this century and beyond, if corals are able to recolonise its surface. Citation: Woodroffe, C. D., B. P. Brooke, M. Linklater, D. M. Kennedy, B. G. Jones, C. Buchanan, R. Mleczko, Q. Hua, and J. Zhao (2010), Response of coral reefs to climate change: Expansion and demise of the southernmost Pacific coral reef, Geophys. Res. Lett., 37, L15602, doi:10.1029/2010GL044067.

Regional Scale Coastal Mapping to Underpin Strategic Land Use Planning in Southeast Australia

ABSTRACT Hanslow D.J.; Dela-Cruz J.; Morris B.D.; Kinsela M.A.; Foulsham E.; Linklater M., and Pritchard T.R., 2016. Regional scale coastal mapping to underpin strategic land use planning in southeast Australia. In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 987–991. Coconut Creek (Florida), ISSN 0749-0208. In the current study we develop spatial data to inform strategic land use and coastal planning which considers coastal hazards and the protection, maintenance and in some cases, restoration of our waterways. The benefits of sustainable coastal development underpinned by a well-established understanding of coastal processes and our ability to avoid negative impacts from inappropriate placement of development are well understood. With climate change and increasing use of coastal systems there is increasing need to identify and manage both current and possible future risk exposure. Mapping is undertaken to allow upfront identification of risks and benefits associated with potential future land use as well fundamental data to help inform coastal assessments. This will help ensure impacts on the coastal environment are minimised and impacts on proposed development from coastal hazards are avoided. The study has several parallel components addressing estuarine water quality and ecosystem health, sea level rise inundation, coastal erosion and sediment/geomorphic setting. Additional benefits of the project include risk based assessment to enable prioritisation of effort to address existing development which is either exposed to coastal hazards or having an impact on coastal waterways.

Geomorphic Features and Infauna Diversity of a Subtropical Mid-Ocean Carbonate Shelf: Lord Howe Island, Southwest Pacific Ocean

Publisher Summary Lord Howe Island (31°33S, 159°04E) sits approximately 580 km east of Australia in the southwest Pacific Ocean. This remote island is the subaerial remnant of a hot-spot volcano that erupted between 6.6 and 7.2 Ma and comprises a mid-ocean basaltic sequence. Erosion of these basalts has dominated island evolution since the cessation of volcanism, creating a rhomboidal-shaped shelf around Lord Howe Island, 24 km wide and 36 km from north to south. As part of a large collaborative program of marine biodiversity research, the shelf around Lord Howe Island was selected as an area representative of a shallow (20–120 m) mid-ocean carbonate shelf environment. The relict reef comprises sand sheet, macroalgae, and hardground habitats. Inshore of the relict reef a sandy basin (mean depth 45 m) has thick sand deposits. Offshore of the relict reef is a relatively flat outer shelf (mean depth 60 m) with bedrock exposures and sandy habitat. Infauna species abundance and richness were similar for sediment samples collected on the outer shelf and relict reef, while samples from the basin had significantly lower infauna abundance and richness. The irregular shelf morphology appears to determine the distribution and character of sandy substrates and local oceanographic conditions, which in turn influence the distribution of different types of infauna communities.

Integrating Seafloor Habitat Mapping and Fish Assemblage Patterns Improves Spatial Management Planning in a Marine Park

ABSTRACT Malcolm, H.A., Jordan, A., Schultz, A.L., Smith, S.D.A., Ingleton, T., Foulsham, E., Linklater, M., Davies, P., Ferrari, R., Hill, N., and Lucieer, V., 2016. Integrating seafloor habitat mapping and fish assemblage patterns improves spatial management planning in a marine park. In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 1292 - 1296. Coconut Creek (Florida), ISSN 0749-0208. Marine Protected Areas (MPAs) are important spatial mechanisms for managing human activities, if effectively planned. The Solitary Islands Marine Park (SIMP), covering 720 km2 of coastal waters in New South Wales, Australia, includes reef and unconsolidated habitats up to 17 km from shore and 75 m depth. When established in 1991, there was limited knowledge of biotic patterns, seafloor habitats and habitat-biotic relationships in the multiple-use SIMP, which constrained effective conservation planning. Subsequent mapping of sub-tidal habitats from aerial photography and single-beam acoustics improved habitat representation following rezoning in 2002 using Comprehensive, Adequate, Representative (CAR) principles and assisted site selection for diver surveys of fishes, a key surrogate taxon. In 2006, a swath acoustic mapping program commenced, which mapped ~35% of the MPA. This has produced high-resolution data on seafloor habitats, including depths >50 m. Bathymetry and backscatter layers have facilitated targeted deployment of Baited Remote Underwater Video (BRUV) to test hypotheses about associations between fishes and physical habitat characteristics. Strong and persistent patterns in fish assemblage composition in relation to particular habitat characteristics provided the basis for a Habitat Classification Scheme (HCS) to be refined with the following categories: substratum (consolidated, unconsolidated), cross-shelf position (inshore, mid, offshore) and depth (shallow, intermediate, deep). Further refinement of unconsolidated substratum into gravel and sand habitats, which were mapped using backscatter layers, improves this classification. The HCS, which integrates habitat and biotic patterns, greatly increases the potential for effective spatial management planning in the SIMP when used with spatial planning tools (e.g. Marxan).