Passive acoustic monitoring is gaining popularity in ecology as a practical and non-invasive approach to surveying ecosystems. This technique is increasingly being used to monitor terrestrial ...systems, particularly bird populations, given that it can help to track temporal dynamics of populations and ecosystem health without the need for expensive resampling. We suggest that underwater acoustic monitoring presents a viable, non-invasive, and largely unexplored approach to monitoring freshwater ecosystems, yielding information about three key ecological elements of aquatic environments - (1) fishes, (2) macroinvertebrates, and (3) physicochemical processes - as well as providing data on anthropogenic noise levels. We survey the literature on this approach, which is substantial but scattered across disciplines, and call for more cross-disciplinary work on recording and analysis techniques. We also discuss technical issues and knowledge gaps, including background noise, spatiotemporal variation, and the need for centralized reference collection repositories. These challenges need to be overcome before the full potential of passive acoustics in dynamic detection of biophysical processes can be realized and used to inform conservation practitioners and managers.
Planning for the remediation of multiple threats is crucial to ensure the long term persistence of biodiversity. Limited conservation budgets require prioritizing which management actions to ...implement and where. Systematic conservation planning traditionally assumes that all the threats in priority sites are abated (fixed prioritization approach). However, abating only the threats affecting the species of conservation concerns may be more cost-effective. This requires prioritizing individual actions independently within the same site (independent prioritization approach), which has received limited attention so far. We developed an action prioritization algorithm that prioritizes multiple alternative actions within the same site. We used simulated annealing to find the combination of actions that remediate threats to species at the minimum cost. Our algorithm also accounts for the importance of selecting actions in sites connected through the river network (i.e., connectivity). We applied our algorithm to prioritize actions to address threats to freshwater fish species in the Mitchell River catchment, northern Australia. We compared how the efficiency of the independent and fixed prioritization approach varied as the importance of connectivity increased. Our independent prioritization approach delivered more efficient solutions than the fixed prioritization approach, particularly when the importance of achieving connectivity was high. By spatially prioritizing the specific actions necessary to remediate the threats affecting the target species, our approach can aid cost-effective habitat restoration and land-use planning. It is also particularly suited to solving resource allocation problems, where consideration of spatial design is important, such as prioritizing conservation efforts for highly mobile species, species facing climate change-driven range shifts, or minimizing the risk of threats spreading across different realms.
Aim: Recent efforts to apply the principles of systematic conservation planning to freshwater ecosystems have focused on the special connected nature of these systems as a way to ensure adequacy ...(long-term maintenance of biodiversity). Connectivity is important in maintaining biodiversity and key ecological processes in freshwater environments and is of special relevance for conservation planning in these systems. However, freshwater conservation planning has focused on longitudinal connectivity requirements within riverine ecosystems, while other habitats, such as floodplain wetlands or lakes and connections among them, have been overlooked. Here, we address this gap by incorporating a new component of connectivity in addition to the traditional longitudinal measure. Location: Northern Australia. Methods: We integrate lateral connections between freshwater areas (e.g. lakes and wetlands) that are not directly connected by the river network and the longitudinal upstream—downstream connections. We demonstrate how this can be used to incorporate ecological requirements of some water-dependent taxa that can move across drainage divides, such as waterbirds. Results: When applied together, the different connectivity rules allow the identification of priority areas that contain whole lakes or wetlands, their closest neighbours whenever possible, and the upstream/downstream reaches of rivers that flow into or from them. This would facilitate longitudinal and lateral movements of biota while minimizing the influence of disturbances potentially received from upstream or downstream reaches. Main conclusions: This new approach to defining and applying different connectivity rules can help improve the adequacy of freshwater-protected areas by enhancing movements of biodiversity within priority areas. The integration of multiple connectivity needs can also serve as a bridge to integrate freshwater and terrestrial conservation planning.
Summary
1. The importance of hydrologic variability for shaping the biophysical attributes and functioning of riverine ecosystems is well recognised by ecologists and water resource managers. In ...addition to the ecological dependences of flow for aquatic organisms, human societies modify natural flow regimes to provide dependable ecological services, including water supply, hydropower generation, flood control, recreation and navigation. Management of scarce water resources needs to be based on sound science that supports the development of environmental flow standards at the regional scale.
2. Hydrological classification has long played an essential role in the ecological sciences for understanding geographic patterns of riverine flow variability and exploring its influence on biological communities, and more recently, has been identified as a critical process in environmental flow assessments.
3. We present the first continental‐scale classification of hydrologic regimes for Australia based on 120 metrics describing ecologically relevant characteristics of the natural hydrologic regime derived from discharge data for 830 stream gauges. Metrics were calculated from continuous time series (15–30 years of record constrained within a 36‐year period) of mean daily discharge data, and classification was undertaken using a fuzzy partitional method – Bayesian mixture modelling.
4. The analysis resulted in the most likely classification having 12 classes of distinctive flow‐regime types differing in the seasonal pattern of discharge, degree of flow permanence (i.e. perennial versus varying degrees of intermittency), variations in flood magnitude and frequency and other aspects of flow predictability and variability. Geographic, climatic and some catchment topographic factors were generally strong discriminators of flow‐regime classes. The geographical distribution of flow‐regime classes showed varying degrees of spatial cohesion, with stream gauges from certain flow‐regime classes often being non‐contiguously distributed across the continent. These results support the view that spatial variation in hydrology is determined by interactions among climate, geology, topography and vegetation at multiple spatial and temporal scales. Decision trees were also developed to provide the ability to determine the natural flow‐regime class membership of new stream gauges based on their key environmental and/or hydrological characteristics.
5. The need to recognise hydrologic variation at multiple spatial scales is an important first step to setting regional‐scale environmental flow management strategies. We expect that the classification produced here can underpin the development of a greater understanding of flow‐ecology relationships in Australia, and management efforts aimed at prescribing environmental flows for riverine restoration and conservation.
Understanding how sensitive aquatic ecosystems respond to climate change is essential for effective biodiversity conservation and management. The Tibetan Plateau (TP) is one of the most globally ...sensitive areas to climate change with potentially serious implications for resident fish populations and aquatic food webs. However, how the growth of TP fish responds to climate change, and how this response varies with the trophic level of different species remain unknown. We established growth-increment chronologies of two important Schizothoracinae fishes that are endemic to the TP (e.g., the omnivorous Schizopygopsis younghusbandi and the carnivorous Oxygymnocypris stewartii) from the Yarlung Tsangpo River, using otolith increment width measurements and dendrochronological methods. These growth chronologies were correlated with key indicators of environmental variation (temperature, precipitation, and river discharge) to examine the potential effects of climate change. The two chronologies displayed synchronous responses to recent climate change. In this glacial-fed river, the growth of both fish species was significantly and negatively correlated with the mean annual air temperature, while it was positively but not significantly correlated with precipitation and discharge. The higher trophic level species O. stewartii was more sensitive to climate than was the lower trophic level species S. younghusbandi, with temperature variables explaining a higher proportion of growth variability in O. stewartii (64.6%) than in S. younghusbandi (46.4%). The results collectively indicate that both species are highly sensitive to climate change, which may affect fish growth by altering water environment, fish physiological fitness and food availability. This study provides further empirical evidence of the utility of growth-increment chronologies for investigating the effects of climate change on aquatic ecosystems across different basins and water body types of the TP. These findings can inform conservation and management actions related to addressing climate change on the TP and other high-elevation temperate systems found worldwide.
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•Fish growth-environment relations were established in a river fed by glacial water.•Growth chronologies of fish were established using dendrochronological methods.•Fish chronologies were negatively correlated with air temperature.•Higher trophic level (TP) fish were more sensitive to climate than lower TP fish.
The coarse spatial resolution of the Gravity Recovery and Climate Experiment (GRACE) dataset has limited its application in local water resource management and accounting. Despite efforts to improve ...GRACE spatial resolution, achieving high resolution downscaled grids that correspond to local hydrological behaviour and patterns is still limited. To overcome this issue, we propose a novel statistical downscaling approach to improve the spatial resolution of GRACE-terrestrial water storage changes (ΔTWS) using precipitation, evapotranspiration (ET), and runoff data from the Australian Water Outlook. These water budget components drive changes in the GRACE water column in much of the global land area. Here, the GRACE dataset is downscaled from the original resolution of 1.0° × 1.0° to 0.05° × 0.05° over a large hydro-geologic basin in northern Australia (the Cambrian Limestone Aquifer-CLA), capturing sub- grid heterogeneity in ΔTWS of the region. The downscaled results are validated using data from 12 in-situ groundwater monitoring stations and water budget estimates of the CLA's land water storage changes from April 2002 to June 2017. The change in water storage over time (ds/dt) estimated from the water budget model was weakly correlated (r = 0.34) with the downscaled GRACE ΔTWS. The weak relationship was attributed to the possible uncertainties inherent in the ET datasets used in the water budget, particularly during the summer months. Our proposed methodology provides an opportunity to improve freshwater reporting using GRACE and enhances the feasibility of downscaling efforts for other hydrological data to strengthen local-scale applications.
This study uses species distribution modeling and physiological and functional traits to predict the impacts of climate change on native freshwater fish in the Murray-Darling Basin, Australia. We ...modelled future changes in taxonomic and functional diversity in 2050 and 2080 for two scenarios of carbon emissions, identifying areas of great interest for conservation. Climatic-environmental variables were used to model the range of 23 species of native fish under each scenario. The consensus model, followed by the physiological filter of lethal temperature was retained for interpretation. Our study predicts a severe negative impact of climate change on both taxonomic and functional components of ichthyofauna of the Murray-Darling Basin. There was a predicted marked contraction of species ranges under both scenarios. The predictions showed loss of climatically suitable areas, species and functional characters. There was a decrease in areas with high values of functional richness, dispersion and uniqueness. Some traits are predicted to be extirpated, especially in the most pessimistic scenario. The climatic refuges for fish fauna are predicted to be in the southern portion of the basin, in the upper Murray catchment. Incorporating future predictions about the distribution of ichthyofauna in conservation management planning will enhance resilience to climate change.
When identifying conservation priorities, the accuracy of conservation assessments is constrained by the quality of data available. Despite previous efforts exploring how to deal with imperfect ...datasets, little is known about how data uncertainty translates into errors in conservation planning outcomes. Here, we evaluate the magnitude of commission and omission error, effectiveness and efficiency of conservation planning outcomes derived from three datasets with increasing data quality. We demonstrate that investing in data acquisition might not always be the best strategy as the magnitude of errors introduced by new sites/species can exceed the benefits gained. There was a trade-off between effectiveness and efficiency due to poorly sampled rare species. Given that data acquisition is limited by the high cost and time required, we recommend focusing on improving the quality of data for those species with the highest level of uncertainty (rare species) when acquiring new data.
Budgeting for biodiversity conservation requires realistic estimates of threat abatement costs. However, data on threat management costs are often unavailable or unable to be extrapolated across ...relevant locations and scales. Conservation expenditure largely occurs without a priori cost estimates of management activities and is not recorded in ways that can inform future budgets or cost‐effective management decisions.
We provided transparent, broadly applicable cost models for 18 Threat Abatement Strategies aimed at managing the processes threatening Australia's biodiversity. We defined the actions required to implement each strategy and used a consistent structure to classify costs of labour, travel, consumables and equipment. We drew upon expert knowledge and published literature to parameterise each model, estimating the implementation cost of each strategy across the Australian continent, accounting for spatial variables such as threat presence, terrain, and travel distance.
Estimated annualised costs for the threat abatement strategies varied considerably between strategies and across Australia, ranging from $24 to $879,985 per km2 ($0.24–$8880 per ha). On average, labour was the largest cost component (49%), followed by consumables (37%), travel (13%) and equipment (2%). Based on national scale variables and assumptions, cost estimates across Australia for each threat abatement strategy ranged from +44% and −33% of the most common cost estimate.
Policy implications. We provide a consistent and transparent approach to budgeting for threat abatement strategies, aiming to improve conservation planning processes, outcomes, and reporting across Australia. In addition, understanding the budget required to achieve threat management outcomes can aid revenue‐raising and target setting. The models, cost layers and estimates we generate provide the basis for a nationally consistent approach for estimating and recording the cost of biodiversity management strategies, which should be continually updated and improved with local‐scale information over time.
We provide a consistent and transparent approach to budgeting for threat abatement strategies, aiming to improve conservation planning processes, outcomes, and reporting across Australia. In addition, understanding the budget required to achieve threat management outcomes can aid revenue‐raising and target setting. The models, cost layers and estimates we generate provide the basis for a nationally consistent approach for estimating and recording the cost of biodiversity management strategies, which should be continually updated and improved with local‐scale information over time.
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