Publications by authors named "Andrew Olds"

Human impacts lead to widespread changes in the abundance, diversity and traits of shark assemblages, altering the functioning of coastal ecosystems. The functional consequences of shark declines are often poorly understood due to the absence of empirical data describing long-term change. We use data from the Queensland Shark Control Program in eastern Australia, which has deployed mesh nets and baited hooks across 80 beaches using standardised methodologies since 1962.

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Sandy beaches are iconic interfaces that functionally link the ocean with the land via the flow of organic matter from the sea. These cross-ecosystem fluxes often comprise uprooted seagrass and dislodged macroalgae that can form substantial accumulations of detritus, termed 'wrack', on sandy beaches. In addition, the tissue of the carcasses of marine animals that regularly wash up on beaches form a rich food source ('carrion') for a diversity of scavenging animals.

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Landscape modification alters the condition of ecosystems and the complexity of terrain, with consequences for animal assemblages and ecosystem functioning. In coastal seascapes, dredging is routine practice for extracting sediments and maintaining navigation channels worldwide. Dredging modifies processes and assemblages by favouring species with wide trophic niches, diverse habitat requirements and tolerances to dredge-related eutrophication and sedimentation.

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Animals can respond to human impacts by favouring different morphological traits or by exploiting different food resources. We quantified the morphology and diet of four functionally different fish species (n = 543 fish) from 13 estuaries with varying degrees of human modification in Queensland, Australia. We found differences in the responses of trophic groups to the environmental conditions of estuaries; principally the extent of seagrass in the estuary, and the amount of shoreline and catchment urbanisation.

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The global lockdown to mitigate COVID-19 pandemic health risks has altered human interactions with nature. Here, we report immediate impacts of changes in human activities on wildlife and environmental threats during the early lockdown months of 2020, based on 877 qualitative reports and 332 quantitative assessments from 89 different studies. Hundreds of reports of unusual species observations from around the world suggest that animals quickly responded to the reductions in human presence.

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Connectivity is fundamentally important for shaping the resilience of complex human and natural networks when systems are disturbed. Ecosystem resilience is, in part, shaped by the spatial arrangement of habitats, the permeability and fluxes between them, the stabilising functions performed by organisms, their dispersal traits, and the interactions between functions and stressor types. Controlled investigations of the relationships between these phenomena under multiple stressors are sparse, possibly due to logistic and ethical difficulties associated with applying and controlling stressors at landscape scales.

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The global distribution of primary production and consumption by humans (fisheries) is well-documented, but we have no map linking the central ecological process of consumption within food webs to temperature and other ecological drivers. Using standardized assays that span 105° of latitude on four continents, we show that rates of bait consumption by generalist predators in shallow marine ecosystems are tightly linked to both temperature and the composition of consumer assemblages. Unexpectedly, rates of consumption peaked at midlatitudes (25 to 35°) in both Northern and Southern Hemispheres across both seagrass and unvegetated sediment habitats.

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Human activities in coastal catchments can cause the accumulation of pollutants in seafood. We quantified the concentration of heavy metals, pesticides and PFASs in the flesh of the fisheries species yellowfin bream Acanthopagrus australis (n = 57) and mud crab Scylla serrata (n = 65) from 13 estuaries in southeast Queensland, Australia; a region with a variety of human land uses. Pollutants in yellowfin bream were best explained by the extent of intensive uses in the catchment.

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Article Synopsis
  • Estuaries play a crucial role for coastal cities, often becoming engineered environments with high nutrient levels due to urbanization.
  • A study across 22 estuaries in eastern Australia reveals that urbanization affects fish diversity and abundance, with certain trophic groups thriving in urbanized areas.
  • The findings highlight that the relationship between fish assemblages, urbanization, and habitat transformation is complex, suggesting that successful estuarine conservation efforts must consider both environmental context and water quality.
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Seascape connectivity (landscape connectivity in the sea) can modify reserve performance in low-energy marine ecosystems (e.g., coral reefs, mangroves, and seagrass), but it is not clear whether similar spatial linkages also shape reserve effectiveness on high-energy, exposed coastlines.

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The response of seagrass systems to a severe disturbance provides an opportunity to quantify the degree of resilience in different meadows, and subsequently to test whether there is a genetic basis to resilience. We used existing data on levels of long-standing disturbance from poor water quality, and the responses of seagrass () after an extreme flood event in Moreton Bay, Queensland, Australia. Sites were grouped into high and low disturbance categories, in which seagrass showed high and low resilience, respectively, as determined by measuring rates of key feedback processes (nutrient removal, suppression of sediment resuspension, and algal grazing), and physiological and morphological traits.

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  • The study investigates how introduced species, specifically red foxes, influence ecological functions like carrion removal along Eastern Australia's beaches, focusing on their interactions with native raptors.
  • Researchers expected to find that the presence of foxes would enhance carrion removal, especially when there was a lot of carrion available, due to reduced competition for food.
  • Results showed that while scavenger dynamics varied by location and time, overall carrion consumption remained consistent across different areas, suggesting that the presence of red foxes has a neutral effect on ecological function beyond just carrion consumption.
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We compared the sensitivity of algae and hermit crabs to seasonal shifts in the dominance of continuous sewage discharge vs. pulsed inputs of terrestrial material to a subtropical bay. During periods of low rainfall, when sewage was proportionately more important than diffuse loads from adjacent catchments, algae and crabs provided comparable information on the spatial distribution of N pollution.

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  • This study investigates how beach characteristics influence nesting success for green and loggerhead turtles, focusing on factors like beach shape, vegetation, and urban development.
  • Researchers analyzed turtle nesting locations along Australia’s Sunshine Coast, looking at their distance from urban areas, light exposure, and specific beach features using advanced digital modeling.
  • Findings indicate turtles didn’t consistently choose nests based on environmental traits but tended to prefer areas close to vegetation and with moderate artificial light exposure, laying groundwork for future conservation strategies to protect nesting sites.
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Management authorities seldom have the capacity to comprehensively address the full suite of anthropogenic stressors, particularly in the coastal zone where numerous threats can act simultaneously to impact reefs and other ecosystems. This situation requires tools to prioritise management interventions that result in optimum ecological outcomes under a set of constraints. Here we develop one such tool, introducing a Bayesian Belief Network to model the ecological condition of inshore coral reefs in Moreton Bay (Australia) under a range of management actions.

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Coastal birds are critical ecosystem constituents on sandy shores, yet are threatened by depressed reproductive success resulting from direct and indirect anthropogenic and natural pressures. Few studies examine clutch fate across the wide range of environments experienced by birds; instead, most focus at the small site scale. We examine survival of model shorebird clutches as an index of true clutch survival at a regional scale (∼200 km), encompassing a variety of geomorphologies, predator communities, and human use regimes in southeast Queensland, Australia.

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Article Synopsis
  • Many bird species that breed on ocean beaches face conservation challenges due to their dependence on invertebrates for food, particularly in areas affected by human recreation.
  • An experiment in Victoria, Australia showed that foot traffic leads to significant declines in invertebrate abundance and species diversity, especially impacting rare species integral to the diet of birds like the threatened Hooded Plover.
  • The findings suggest that trampling is a serious threat to these birds, indicating a need for conservation strategies that involve managing and improving food resources in their breeding habitats.
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Species composition is expected to alter ecological function in assemblages if species traits differ strongly. Such effects are often large and persistent for nonnative carnivores invading islands. Alternatively, high similarity in traits within assemblages creates a degree of functional redundancy in ecosystems.

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Determining the position of range edges is the first step in developing an understanding of the ecological and evolutionary dynamics in play as species' ranges shift in response to climate change. Here, we study the leading (poleward) range edge of Ocypode cordimanus, a ghost crab that is common along the central to northern east coast of Australia. Our study establishes the poleward range edge of adults of this species to be at Merimbula (36.

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Connectivity is a pivotal feature of landscapes that affects the structure of populations and the functioning of ecosystems. It is also a key consideration in conservation planning. But the potential functional effects of landscape connectivity are rarely evaluated in a conservation context.

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The relationship between ecological impact and ecosystem structure is often strongly nonlinear, so that small increases in impact levels can cause a disproportionately large response in ecosystem structure. Nonlinear ecosystem responses can be difficult to predict because locally relevant data sets can be difficult or impossible to obtain. Bayesian networks (BN) are an emerging tool that can help managers to define ecosystem relationships using a range of data types from comprehensive quantitative data sets to expert opinion.

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Identification of critical life-stage habitats is key to successful conservation efforts. Juveniles of some species show great flexibility in habitat use while other species rely heavily on a restricted number of juvenile habitats for protection and food. Considering the rapid degradation of coastal marine habitats worldwide, it is important to evaluate which species are more susceptible to loss of juvenile nursery habitats and how this differs across large biogeographic regions.

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Climate change is predicted to increase the transmission of many vector-borne pathogens, representing an increasing threat to a safe blood supply. In early 2011, Australia experienced catastrophic rainfall and flooding, coupled with increased arbovirus transmission. We used Ross River (RRV) and Barmah Forest (BFV) viruses as test cases to investigate the potential risk posed to Australia's blood supply after this period of increased rainfall .

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Complexity is increasingly the hallmark in environmental management practices of sandy shorelines. This arises primarily from meeting growing public demands (e.g.

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