ORCID Profile
0000-0001-7061-5068
Current Organisation
University of Tasmania
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Publisher: Elsevier BV
Date: 10-2022
DOI: 10.1016/J.CUB.2022.07.067
Abstract: Warming seas, marine heatwaves, and habitat degradation are increasingly widespread phenomena affecting marine bio ersity, yet our understanding of their broader impacts is largely derived from collective insights from independent localized studies. Insufficient systematic broadscale monitoring limits our understanding of the true extent of these impacts and our capacity to track these at scales relevant to national policies and international agreements. Using an extensive time series of co-located reef fish community structure and habitat data spanning 12 years and the entire Australian continent, we found that reef fish community responses to changing temperatures and habitats are dynamic and widespread but regionally patchy. Shifts in composition and abundance of the fish community often occurred within 2 years of environmental or habitat change, although the relative importance of these two mechanisms of climate impact tended to differ between tropical and temperate zones. The clearest of these changes on temperate and subtropical reefs were temperature related, with responses measured by the reef fish thermal index indicating reshuffling according to the thermal affinities of species present. On low latitude coral reefs, the community generalization index indicated shifting dominance of habitat generalist fishes through time, concurrent with changing coral cover. Our results emphasize the importance of maintaining local ecological detail when scaling up datasets to inform national policies and global bio ersity targets. Scaled-up ecological monitoring is needed to discriminate among increasingly erse drivers of large-scale bio ersity change and better connect presently disjointed systems of bio ersity observation, indicator research, and governance.
Publisher: Elsevier BV
Date: 09-2015
DOI: 10.1016/J.MARPOLBUL.2015.06.049
Abstract: Intensive fish culture in open sea pens delivers large amounts of nutrients to coastal environments. Relative to particulate waste impacts, the ecological impacts of dissolved wastes are poorly known despite their potential to substantially affect nutrient-assimilating components of surrounding ecosystems. Broad-scale enrichment effects of salmonid farms on Tasmanian reef communities were assessed by comparing macroalgal cover at four fixed distances from active fish farm leases across 44 sites. Macroalgal assemblages differed significantly between sites immediately adjacent (100m) to fish farms and reference sites at 5km distance, while sites at 400m and 1km exhibited intermediate characteristics. Epiphyte cover varied consistently with fish farm impacts in both sheltered and exposed locations. The green algae Chaetomorpha spp. predominated near fish farms at swell-exposed sites, whereas filamentous green algae showed elevated densities near sheltered farms. Cover of canopy-forming perennial algae appeared unaffected by fish farm impacts.
Publisher: The Royal Society
Date: 14-12-2022
Abstract: Ecosystem structure and function are increasingly threatened by changing climate, with profound effects observed globally in recent decades. Based on standardized visual censuses of reef bio ersity, we describe 27 years of community-level change for fishes, mobile macroinvertebrates and macroalgae in the Tasmanian ocean-warming hotspot. Significant ecological change was observed across 94 reef sites (5–10 m depth range) spanning four coastal regions between three periods (1992–95, 2006–07, 2017–19), which occurred against a background of pronounced sea temperature rise (+0.80°C on average). Overall, fish biomass increased, macroinvertebrate species richness and abundance decreased and macroalgal cover decreased, particularly during the most recent decade. While reef communities were relatively stable and warming was slight between the 1990s and mid-2000s (+0.12°C mean temperature rise), increased abundances of warm affinity fishes and invertebrates accompanied warming during the most recent decade (+0.68°C rise). However, significant rises in the community temperature index (CTI) were only found for fishes, invertebrates and macroalgae in some regions. Coastal warming was associated with increased fish biomass of non-targeted species in fished zones but had little effect on reef communities within marine reserves. Higher abundances of larger fishes and lobsters inside reserves appeared to negate impacts of ‘thermophilization’.
Publisher: ACM
Date: 17-10-2022
Publisher: Elsevier BV
Date: 06-2015
DOI: 10.1016/J.MARPOLBUL.2015.03.023
Abstract: Urbanisation of the coastal zone represents a key threat to marine bio ersity, including rocky reef communities which often possess disproportionate ecological, recreational and commercial importance. The nature and magnitude of local urban impacts on reef bio ersity near three Australian capital cities were quantified using visual census methods. The most impacted reefs in urbanised embayments were consistently characterised by smaller, faster growing species, reduced fish biomass and richness, and reduced mobile invertebrate abundance and richness. Reef faunal distribution varied significantly with heavy metals, local population density, and proximity to city ports, while native fish and invertebrate communities were most depauperate in locations where invasive species were abundant. Our study adds impetus for improved urban planning and pollution management practises, while also highlighting the potential for skilled volunteers to improve the tracking of changes in marine bio ersity values and the effectiveness of management intervention.
Publisher: Springer Science and Business Media LLC
Date: 22-03-2023
Publisher: Elsevier BV
Date: 12-2020
No related grants have been discovered for Elizabeth Oh.