Wernberg T.,University of Western Australia |
Wernberg T.,Australian Institute of Marine Science |
Wernberg T.,Edith Cowan University |
Russell B.D.,University of Adelaide |
And 11 more authors.
Journal of Experimental Marine Biology and Ecology | Year: 2011
Temperate Australia is a global hotspot for marine biodiversity and its waters have experienced well-above global average rates of ocean warming. We review the observed impacts of climate change (e.g. warming, ocean acidification, changes in storm patterns) on subtidal temperate coasts in Australia and assess how these systems are likely to respond to further change. Observed impacts are region specific with the greatest number of species responses attributable to climate change reported in south-eastern Australia, where recent ocean warming has been most pronounced. Here, a decline of giant kelp (Macrocystis pyrifera) and poleward range extension of a key herbivore (sea urchin) and other trophically important reef organisms has occurred. Although, evidence of changes on other coastlines around Australia is limited, we suggest that this is due to a lack of data rather than lack of change. Because of the east-west orientation of the south coast, most of Australia's temperate waters are found within a narrow latitudinal band, where any southward movement of isotherms is likely to affect species across very large areas. Future increases in temperature are likely to result in further range shifts of macroalgae and associated species, with range contractions and local extinctions to be expected for species that have their northern limits along the southern coastline. While there is currently no evidence of changes attributable to non-temperature related climate impacts, potentially due to a lack of long-term observational data, experimental evidence suggests that ocean acidification will result in negative effects on calcifying algae and animals. More importantly, recent experiments suggest the combined effects of climate change and non-climate stressors (overharvesting, reduced water quality) will lower the resilience of temperate marine communities to perturbations (e.g. storms, diseases, and introduced species), many of which are also predicted to increase in frequency and/or severity. Thus climate change is likely to, both by itself and in synergy with other stressors, impose change to southern Australian coastal species, including important habitat-forming algae and the associated ecological functioning of temperate coasts. Management of local and regional-scale stresses may increase the resistance of temperate marine communities to climate stressors and as such, provides an attractive tool for building resilience in temperate systems. © 2011 Elsevier B.V.
Demers M.C.A.,University of Wollongong |
Davis A.R.,University of Wollongong |
Knott N.A.,NSW Marine Parks Authority
Marine Environmental Research | Year: 2013
Permanent boat moorings have contributed to the decline of seagrasses worldwide, prompting the development of 'seagrass-friendly' moorings. We contrasted seagrass cover and density (predominantly Posidonia australis) in the vicinity of three mooring types and nearby reference areas lacking moorings in Jervis Bay, Australia. We examined two types of 'seagrass-friendly' mooring and a conventional 'swing' mooring. 'Swing' moorings produced significant seagrass scour, denuding patches of ∼9 m radius. Seagrass-friendly 'cyclone' moorings produced extensive denuded patches (average radius of ∼18 m). Seagrass-friendly 'screw' moorings, conversely, had similar seagrass cover to nearby reference areas. Our findings reinforce previous work highlighting the negative effects of 'swing' and 'cyclone' moorings. In contrast, the previously unstudied 'screw' moorings were highly effective. We conclude that regular maintenance of moorings and the monitoring of surrounding seagrass are required to ensure that 'seagrass-friendly' moorings are operating effectively. This is important, as following damage Posidonia will take many decades to recover. © 2012 Elsevier Ltd.
Hellyer C.B.,University of New South Wales |
Harasti D.,NSW Marine Parks Authority |
Poore A.G.B.,University of New South Wales
Aquatic Conservation: Marine and Freshwater Ecosystems | Year: 2011
Artificial habitats are a common feature of urban marine environments and usually support different assemblages of marine organisms in contrast to neighbouring natural habitats. Despite these differences, artificial habitats can be managed to benefit biodiversity, either by the addition of structures to provide habitat where little natural habitat remains, or by engineering existing structures to better support native populations. Seahorses are listed as protected species in New South Wales, Australia, and are of conservation concern worldwide. The physical structure of nets used to protect popular swimming beaches in a highly urbanized estuary, Sydney Harbour, was manipulated to test the hypotheses that more structurally complex habitats would support higher abundances of the seahorse Hippocampus whitei that use these structures and their potential prey (mobile crustaceans). The simple addition of frayed net material to construct a more structurally complex net habitat supported higher abundances of H. whitei than unmanipulated nets in a field experiment over 53days. Habitat preference assays in the laboratory supported the hypothesis that the patterns of distribution observed in the field were due to the preferences of individual seahorses for the more complex habitats. The habitats manipulated to add structural complexity supported much higher abundances of the mobile epifauna (amphipods, copepods) that are consumed by seahorses. The potential therefore exists to engineer artificial structures in urban estuaries to provide habitats that are preferred by vulnerable fauna and their food sources. © 2011 John Wiley & Sons, Ltd.
Brookhouse N.,Southern Cross University of Australia |
Bucher D.J.,Southern Cross University of Australia |
Rose K.,Wildlife Conservation Society |
Kerr I.,NSW Marine Parks Authority |
Gudge S.,NSW Marine Parks Authority
Journal of Ecotourism | Year: 2013
Poorly managed food provisioning to attract wild fish to interact with tourists has many impacts on the fish and surrounding environment. Such impacts can theoretically be managed at sustainable levels, but too often the activity becomes established at unsustainable levels long before management intervention, resulting in dependence, not only of the fish, but also the local economy, making management unpopular and difficult to enforce. For decades feeding fish has been a popular tourist activity at Lord Howe Island. This study documents the intensity of the activity and examines the behavioural and health impacts on the fish. Impacts included habituation, dependency, aggression and altered foraging behaviour, skin lesions, microbial infections, excessive fat deposits, stomach ulcers and excessive parasite burdens. Lord Howe Island supports a small economy dependent upon ecotourism around sustainable interactions with the natural environment and fish feeding is marketed as a major attraction for visitors. Management action, including education and control of food types and quantities, is imperative to ensure the sustainability of fish feeding. This study exemplifies how an initially small-scale interaction between tourists and fish can escalate to pose a threat to the fish, the surrounding ecosystem and the local economy in a marine park of international significance. © 2014 Taylor & Francis.
Gladstone W.,University of Newcastle |
Lindfield S.,University of Newcastle |
Coleman M.,NSW Marine Parks Authority |
Kelaher B.,NSW Marine Parks Authority
Journal of Experimental Marine Biology and Ecology | Year: 2012
Baited remote underwater video stations (BRUVS) are used for monitoring fish assemblages and assessing management effectiveness in reef environments but are infrequently used in estuaries. A review of the BRUVS literature found that most adopted sampling designs from other studies were rarely designed from pilot studies. This potentially compromises their value for monitoring natural and anthropogenic variation. The aims of this study were: (i) to assess the suitability of BRUVS for sampling fishes in estuarine habitats (seagrass beds and unvegetated sediments) and (ii) to develop an optimal and cost effective sampling methodology for each habitat. Fishes in both habitats were sampled independently using BRUVS with soak times of 30, 60, 90. min (n=4). Thirty five species of fishes were recorded including 18 species of economic importance. Mean number of species, mean total Max N and mean Max N of species did not differ among soak times. Precision was generally greater in seagrass and in both habitats it improved with increasing soak time. Bootstrapping revealed that greater improvements in precision occurred from increasing soak time rather than increasing replication. A sampling design with n=5 replicates of 90. min soak time was optimal for most variables. This sampling effort is greater than many current applications of BRUVS. The results highlight the importance of pilot studies to optimise sampling methods and develop cost effective and statistically-robust monitoring programs. © 2012 Elsevier B.V.