School of BioSciences - Research Publications
Permanent URI for this collection
Search Results
1 - 10 of 53
-
ItemNo Preview AvailableCurrent extent and future opportunities for living shorelines in Australia(ELSEVIER, 2024-03-20)Living shorelines aim to enhance the resilience of coastlines to hazards while simultaneously delivering co-benefits such as carbon sequestration. Despite the potential ecological and socio-economic benefits of living shorelines over conventional engineered coastal protection structures, application is limited globally. Australia has a long and diverse coastline that provides prime opportunities for living shorelines using beaches and dunes, vegetation, and biogenic reefs, which may be either natural ('soft' approach) or with an engineered structural component ('hybrid' approach). Published scientific studies, however, have indicated limited use of living shorelines for coastal protection in Australia. In response, we combined a national survey and interviews of coastal practitioners and a grey and peer-reviewed literature search to (1) identify barriers to living shoreline implementation; and (2) create a database of living shoreline projects in Australia based on sources other than scientific literature. Projects included were those that had either a primary or secondary goal of protection of coastal assets from erosion and/or flooding. We identified 138 living shoreline projects in Australia through the means sampled starting in 1970; with the number of projects increasing through time particularly since 2000. Over half of the total projects (59 %) were considered to be successful according to their initial stated objective (i.e., reducing hazard risk) and 18 % of projects could not be assessed for their success based on the information available. Seventy percent of projects received formal or informal monitoring. Even in the absence of peer-reviewed support for living shoreline construction in Australia, we discovered local and regional increases in their use. This suggests that coastal practitioners are learning on-the-ground, however more generally it was stated that few examples of living shorelines are being made available, suggesting a barrier in information sharing among agencies at a broader scale. A database of living shoreline projects can increase knowledge among practitioners globally to develop best practice that informs technical guidelines for different approaches and helps focus attention on areas for further research.
-
ItemGreater Consideration of Animals Will Enhance Coastal Restoration Outcomes(OXFORD UNIV PRESS, 2022-10-30)As efforts to restore coastal habitats accelerate, it is critical that investments are targeted to most effectively mitigate and reverse habitat loss and its impacts on biodiversity. One likely but largely overlooked impediment to effective restoration of habitat-forming organisms is failing to explicitly consider non-habitat-forming animals in restoration planning, implementation, and monitoring. These animals can greatly enhance or degrade ecosystem function, persistence, and resilience. Bivalves, for instance, can reduce sulfide stress in seagrass habitats and increase drought tolerance of saltmarsh vegetation, whereas megaherbivores can detrimentally overgraze seagrass or improve seagrass seed germination, depending on the context. Therefore, understanding when, why, and how to directly manipulate or support animals can enhance coastal restoration outcomes. In support of this expanded restoration approach, we provide a conceptual framework, incorporating lessons from structured decision-making, and describe potential actions that could lead to better restoration outcomes using case studies to illustrate practical approaches.
-
ItemAn environmental DNA approach to informing restoration of the functionally extinct oyster, Ostrea angasi(WILEY, 2022-11)Abstract The success of oyster reef restoration can be enhanced by data on the distribution of remnant populations to inform the selection of suitable restoration locations. A quantitative polymerase chain reaction‐based environmental DNA (eDNA) assay was designed to provide distribution data for the oyster, Ostrea angasi, whose reefs are functionally extinct in Port Phillip Bay, Australia. Ostrea angasi eDNA accumulation and decay was measured in aquaria containing oysters in low and high densities, prior to testing the efficacy of the eDNA approach for detection of oysters at 15 field sites. Ostrea angasi eDNA accumulated significantly faster in aquaria where more individuals were present, while eDNA became undetectable 2–6 days after oysters were removed in low‐density treatments. The eDNA samples were successful at detecting O. angasi in the field when taken in close proximity of an oyster population. Increasing the sample number and volume could maximize oyster detection, demonstrating the potential of eDNA to identify suitable sites for the restoration of functionally extinct marine ecosystems.
-
ItemNature-based solutions for atoll habitability(ROYAL SOC, 2022-07-04)Atoll societies have adapted their environments and social systems for thousands of years, but the rapid pace of climate change may bring conditions that exceed their adaptive capacities. There is growing interest in the use of 'nature-based solutions' to facilitate the continuation of dignified and meaningful lives on atolls through a changing climate. However, there remains insufficient evidence to conclude that these can make a significant contribution to adaptation on atolls, let alone to develop standards and guidelines for their implementation. A sustained programme of research to clarify the potential of nature-based solutions to support the habitability of atolls is therefore vital. In this paper, we provide a prospectus to guide this research programme: we explain the challenge climate change poses to atoll societies, discuss past and potential future applications of nature-based solutions and outline an agenda for transdisciplinary research to advance knowledge of the efficacy and feasibility of nature-based solutions to sustain the habitability of atolls. This article is part of the theme issue 'Nurturing resilient marine ecosystems'.
-
ItemBorn at the right time? A conceptual framework linking reproduction, development, and settlement in reef fish(WILEY, 2018-01)Parents are expected to make decisions about reproductive timing and investment that maximize their own fitness, even if this does not maximize the fitness of each individual offspring. When offspring survival is uncertain, selection typically favors iteroparity, which means that offspring born at some times can be disadvantaged, while others get lucky. The eventual fate of offspring may be further modified by their own decisions. Are fates of offspring set by birthdates (i.e., determined by parents), or can offspring improve upon the cards they've been dealt? If so, do we see adaptive plasticity in the developmental timing of offspring? We evaluate these questions for a coral reef fish (the sixbar wrasse, Thalassoma hardwicke) that is characterized by extreme iteroparity and flexible larval development. Specifically, we monitored larval settlement to 192 small reefs over 11 lunar months and found that most fish settled during new moons of a lunar cycle (consistent with preferential settlement on dark nights). Settlement was significantly lower than expected by chance during the full moon and last quarter of the lunar cycle (consistent with avoidance of bright nights). Survival after settlement was greatest for fish that settled during times of decreasing lunar illumination (from last quarter to new moon). Fish that settled on the last quarter of the lunar cycle were ~10% larger than fish that settled during other periods, suggesting larvae delay settlement to avoid the full moon. These results are consistent with a numerical model that predicts plasticity in larval development time that enables avoidance of settlement during bright periods. Collectively, our results suggest that fish with inauspicious birthdates may alter their developmental trajectories to settle at better times. We speculate that such interactions between parent and offspring strategies may reinforce the evolution of extreme iteroparity and drive population dynamics, by increasing the survival of offspring born at the "wrong" time by allowing them to avoid the riskiest times of settlement.
-
ItemImpacts of human-induced environmental change in wetlands on aquatic animals(WILEY, 2018-02)Many wetlands harbour highly diverse biological communities and provide extensive ecosystem services; however, these important ecological features are being altered, degraded and destroyed around the world. Despite a wealth of research on how animals respond to anthropogenic changes to natural wetlands and how they use created wetlands, we lack a broad synthesis of these data. While some altered wetlands may provide vital habitat, others could pose a considerable risk to wildlife. This risk will be heightened if such wetlands are ecological traps - preferred habitats that confer lower fitness than another available habitat. Wetlands functioning as ecological traps could decrease both local and regional population persistence, and ultimately lead to extinctions. Most studies have examined how animals respond to changes in environmental conditions by measuring responses at the community and population levels, but studying ecological traps requires information on fitness and habitat preferences. Our current lack of knowledge of individual-level responses may therefore limit our capacity to manage wetland ecosystems effectively since ecological traps require different management practices to mitigate potential consequences. We conducted a global meta-analysis to characterise how animals respond to four key drivers of wetland alteration: agriculture, mining, restoration and urbanisation. Our overarching goal was to evaluate the ecological impacts of human alterations to wetland ecosystems, as well as identify current knowledge gaps that limit both the current understanding of these responses and effective wetland management. We extracted 1799 taxon-specific response ratios from 271 studies across 29 countries. Community- (e.g. richness) and population-level (e.g. density) measures within altered wetlands were largely comparable to those within reference wetlands. By contrast, individual fitness measures (e.g. survival) were often lower, highlighting the potential limitations of using only community- and population-level measures to assess habitat quality. Only four studies provided habitat-preference data, preventing investigation of the potential for altered wetlands to function as ecological traps. This is concerning because attempts to identify ecological traps may detect previously unidentified conservation risks. Although there was considerable variability amongst taxa, amphibians were typically the most sensitive taxon, and thus, may be a valuable bio-indicator of wetland quality. Despite suffering reduced survival and reproduction, measures such as time to and mass at metamorphosis were similar between altered and reference wetlands, suggesting that quantifying metamorphosis-related measures in isolation may not provide accurate information on habitat quality. Our review provides the most detailed evaluation to date of the ecological impacts of human alterations to wetland ecosystems. We emphasise that the role of wetlands in human-altered ecosystems can be complex, as they may represent important habitat but also pose potential risks to animals. Reduced availability of natural wetlands is increasing the importance of altered wetlands for aquatic animals. Consequently, we need to define what represents habitat quality from the perspective of animals, and gain a greater understanding of the underlying mechanisms of habitat selection and how these factors could be manipulated. Furthermore, strategies to enhance the quality of these wetlands should be implemented to maximise their conservation potential.
-
ItemFine-scale variability in elemental composition of estuarine water and otoliths: Developing environmental markers for determining larval fish dispersal histories within estuaries(WILEY, 2018-01)Abstract Otolith chemistry has been widely used as a natural tag for determining environmental histories of fish that migrate across large distances and environmental gradients. However, it is not as well established as to whether otolith chemistry can be a useful tool for determining fine‐scale movement and dispersal patterns of fish, particularly larvae, within estuaries. In this study, we collected water samples and otoliths from larvae of black bream, Acanthopagrus butcheri, an estuarine resident fish, and analyzed each for a suite of trace elements to determine the degree of spatio‐temporal variability in elemental composition and which elements were incorporated into otoliths in relation to their associated water chemistry. We found that there were three distinct water layer signatures based on their Me : Cawater (Me = each element): a freshwater signature, a halocline signature, and a marine signature. There were also significant spatio‐temporal patterns in Me : Caotolith, most notably for Li : Ca, K : Ca, and Mn : Ca. This study provides encouraging evidence for the utility of intra‐estuary otolith chemistry to reconstruct environmental histories during larval development. This application will enable a better understanding of the abundance, timing, and duration of residency in particular water masses and locations that are important larval nursery habitats for species that develop within estuaries.
-
ItemWhen good animals love bad restored habitats: how maladaptive habitat selection can constrain restoration(WILEY, 2017-10)Restoration is increasingly undertaken to ameliorate the risks of habitat loss and transformation to biodiversity. Despite significant expenditure of time and resources world‐wide, restored habitats commonly fail to achieve these objectives. Restoration could fail because animals either avoid restored habitats (perceptual traps) or prefer restored habitats where their fitness is reduced (ecological traps). Consequently, restoration may have a neutral impact or more worryingly provide an additional risk to population persistence. Whether traps arise as an unintended consequence of restoration has largely been unexplored. Our aim is to highlight how traps can compromise restoration efforts and propose ways to reduce this possibility. We first highlight five criteria for successful habitat restoration to identify how and where ecological and perceptual traps could arise and use case studies to demonstrate some of the diverse ways restoration could cause traps. Managing traps that form via restoration depends on reinstating the links between habitat quality and preference. We suggest resource‐based habitat approaches, which consider what represents functional habitats from the perspective of animals, are a potentially useful tool in this regard. Furthermore, cognitive theory may help to improve our understanding of how animals select habitats and to address problematic behaviours as they arise. Synthesis and applications. Restoration will fail if habitat quality and preference are not strongly linked, but this possibility has received limited attention. Our review will help ensure that restored habitats provide the resources required by animals, and that animals assess and respond to these habitats adaptively. We hope to stimulate further discussion between evolutionary, behavioural and restoration ecologists to improve the success of habitat restoration.
-
ItemInteractive effects of shelter and conspecific density shape mortality, growth, and condition in juvenile reef fish(WILEY, 2016-06)How landscape context influences density-dependent processes is important, as environmental heterogeneity can confound estimates of density dependence in demographic parameters. Here we evaluate 19 populations in a shoaling temperate reef fish (Trachinops caudimaculatus) metapopulation within a heterogeneous seascape (Port Phillip Bay, Australia) to show empirically that shelter availability and population density interact to influence juvenile mortality, growth and condition. Although heterogeneity in shelter availability obscured the underlying patterns of density dependence in different ways, the combination of habitat and its interaction with density were two to six times more important than density alone in explaining variation in demographic parameters for juveniles. These findings contradict many small-scale studies and highlight the need for landscape-scale observations of how density dependence interacts with resource availability and competition to better understand how demographic parameters influence the dynamics of metapopulations in heterogeneous environments.
-
ItemSMELL NO EVIL: COPPER DISRUPTS THE ALARM CHEMICAL RESPONSE IN A DIADROMOUS FISH, GALAXIAS MACULATUS(WILEY-BLACKWELL, 2016-09)