Publications by authors named "Ralph Mac Nally"

Waterbirds are highly mobile and have the ability to respond to environmental conditions opportunistically at multiple scales. Mobility is particularly crucial for aggregate-nesting species dependent on breeding habitat in arid and semi-arid wetlands, which can be ephemeral and unpredictable. We aimed to address knowledge gaps about movement routes for aggregate-nesting nomadic waterbird species by tracking them in numbers sufficient to make robust assessment of their movement patterns.

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Waterbird population and species diversity maintenance are important outcomes of wetland conservation management, but knowledge gaps regarding waterbird movements affect our ability to understand and predict waterbird responses to management at appropriate scales. Movement tracking using satellite telemetry is now allowing us to fill these knowledge gaps for highly mobile waterbirds at continental scales, including in remote areas for which data have been historically difficult to acquire. We used GPS satellite telemetry to track the movements of 122 individuals of three species of ibis and spoonbills (Threskiornithidae) in Australia from 2016 to 2023.

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As the United Nations develops a post-2020 global biodiversity framework for the Convention on Biological Diversity, attention is focusing on how new goals and targets for ecosystem conservation might serve its vision of 'living in harmony with nature'. Advancing dual imperatives to conserve biodiversity and sustain ecosystem services requires reliable and resilient generalizations and predictions about ecosystem responses to environmental change and management. Ecosystems vary in their biota, service provision and relative exposure to risks, yet there is no globally consistent classification of ecosystems that reflects functional responses to change and management.

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Predicting the impacts of species introductions long has attracted the attention of ecologists yet there still is limited insight into how impacts on native assemblages vary with the degree of shared evolutionary context. Here, we used data from 535 stream-fish surveys from 15 catchments in north-eastern Spain (99,700 km) to explore whether the relative effects on native fishes differ between fish introductions from two different ecoregions (i.e.

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Nature-based solutions including rooftop-water storage ponds are increasingly adopted in cities as new eco-designs to address climate change issues, such as water scarcity and storm-water runoff. Macrophytes may be valuable additions for treating stored rooftop waters and provisioning other services, including aquaponics, esthetic and wildlife-conservation values. However, the efficacy of macrophyte treatments has not been tested with influxes of different labile carbon loadings such as those occurring in storms.

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Environmental degradation of rivers in agricultural landscapes is typically caused by multiple co-occurring stressors, but how interactions among stressors affect freshwater ecosystems is poorly understood. Therefore, we investigated the sensitivity and specificity of several measures of benthic macroinvertebrate community response to the individual and combined effects of the pesticide sulfoxaflor (SFX), increased sand sedimentation and elevated nutrients using outdoor recirculating mesocosms. Among the single stressor treatments, nutrients had no observable impact and sand only affected one community response measure compared to controls.

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Water quality and riparian communities are among the most affected stream components by agriculture. However, little is known about the effects of riparian management for both aquatic and terrestrial taxa at different spatial scales. Here, we surveyed aquatic (diatoms) and terrestrial taxa (bryophytes, vascular plants, litter-dwelling snails, and ground and volant arthropods), to compare the abundance and richness of riparian taxa and chemical quality between reference and exposed sites in two stream reaches each of c.

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Pesticides are increasingly recognised as a threat to freshwater biodiversity, but their specific ecological effects remain difficult to distinguish from those of co-occurring stressors and environmental gradients. Using mesocosms we examined the effects of an organophosphate insecticide (malathion) on stream macroinvertebrate communities concurrently exposed to a suite of stressors typical of streams in agricultural catchments. We assessed the specificity of the SPEcies At Risk index designed to determine pesticide effects in mesocosm trials (SPEAR).

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Conservation initiatives overwhelmingly focus on terrestrial biodiversity, and little is known about the freshwater cobenefits of terrestrial conservation actions. We sampled more than 1500 terrestrial and freshwater species in the Amazon and simulated conservation for species from both realms. Prioritizations based on terrestrial species yielded on average just 22% of the freshwater benefits achieved through freshwater-focused conservation.

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Article Synopsis
  • Habitat destruction is a major cause of biodiversity loss, and existing research lacks standardization in data collection and analysis, making it hard to draw firm conclusions.
  • A systematic review of the literature yielded 117 studies on species composition in various habitat sizes, revealing a concentration of research in tropical forests, while also covering a range of species including invertebrates and vertebrates.
  • The gathered data on species abundances, sampling efforts, and additional metadata will help create standardized comparisons to better understand how habitat fragmentation impacts biodiversity.
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The increased rate of outbreaks of infectious diseases in ecosystems is a dramatic consequence of global change, particularly when outbreaks affect important resources such as freshwater fish. However, the links between disease-inducing epizootics and widespread human impacts, including nutrient pollution and high water conductivity, in freshwater organisms are largely unexplored. We used data from extensive surveys in northeastern Spain (99,700 km, 15 river catchments, n = 530 sites) to explore the environmental factors that singly, or in combination, are likely to influence the occurrence of the invasive parasite, Lernaea cyprinacea, after accounting for host fish characteristics.

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Article Synopsis
  • Secondary forests (SFs) are increasingly important for carbon storage and biodiversity, regenerating on previously deforested tropical lands.
  • Despite their recovery, SFs do not fully replicate the biodiversity and structure of undisturbed primary forests (UPFs), with an average recovery of 88% species richness after up to 40 years.
  • The study shows that while SFs accumulate carbon and support many species, they cannot replace UPFs, highlighting the need for ongoing conservation efforts in primary forests.
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The effective aridity in riparian areas is increasing from climate change and from human water consumption, which exacerbates the impacts of effluents from wastewater-treatment plants and from catchment run-off in rivers. The potential of natural riparian areas to act as 'green filters' has long been recognized, but the possible ecological benefits of natural riparian areas over large-scale environmental gradients on fish have not been explored in detail. Using an extensive data-set from northeastern Spain (99,700 km, 15 catchments, 530 sites), ours is the first study to ask whether natural riparian vegetation can mitigate the effects of pollution on fish in rivers experiencing water scarcity.

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Examining how the trophic structure of biotic assemblages is affected by human impacts, such as habitat degradation and the introduction of alien species, is important for understanding the consequences of such impacts on ecosystem functioning. We used general linear mixed models and hierarchical partitioning analyses of variance to examine for the first time the applicability of three hypotheses (ecosystem-size, productivity and disturbance) for explaining food-chain length (FCL) in invaded fish assemblages. We used Fishbase trophic level (TL) estimates for 16 native and 18 alien fish species in an extensive riverine system in north-eastern Spain (99,700 km, 15 catchments, 530 sites).

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Agricultural expansion and intensification are major threats to tropical biodiversity. In addition to the direct removal of native vegetation, agricultural expansion often elicits other human-induced disturbances, many of which are poorly addressed by existing environmental legislation and conservation programmes. This is particularly true for tropical freshwater systems, where there is considerable uncertainty about whether a legislative focus on protecting riparian vegetation is sufficient to conserve stream fauna.

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Many estuaries are becoming increasingly eutrophic from human activities within their catchments. Nutrient loads often are used to assess risk of eutrophication to estuaries, but such data are expensive and time consuming to obtain. We compared the percent of fertilized land within a catchment, dissolved inorganic nitrogen loads, catchment to estuary area ratio and flushing time as predictors of the proportion of macroalgae to total vegetation within 14 estuaries in south-eastern Australia.

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When freshwater resources become scarce there is a trade-off between human resource demands and environmental sustainability. The cost of conserving freshwater ecosystems can potentially be reduced by implementing institutional reforms that endow environmental water managers with a permanent water entitlement and the capacity to store, trade and release water. Australia's Murray Darling Basin Plan (MDBP) includes one of the world's most ambitious programs to recover water for the environment, supported by institutional reforms that allow environmental water managers to operate in water markets.

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There is a risk of 'ecological surprises' if multiple potentially interacting stressors are managed individually, which is a question attracting significant current interest. Habitat degradation and species introductions are major threats to global biodiversity, and riverine fish are among the most threatened taxa in the world. Our interest was whether the presence of non-native species can affect native fish sensitivity to water quality deterioration in a large region in northeastern Spain (99,700km, 15 catchments, 530 sites).

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Human society has a profound adverse effect on natural assets as human populations increase and as global climate changes. We need to envisage different futures that encompass plausible human responses to threats and change, and become more mindful of their likely impacts on natural assets. We describe a method for developing a set of future scenarios for a natural asset at national scale under ongoing human population growth and climate change.

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Most natural assets, including native biodiversity (our focus), are under increasing threat from direct (loss of habitat, hunting) and indirect (climate change) human actions. Most human impacts arise from increasing human populations coupled with rises in per capita resource use. The rates of change of human actions generally outpace those to which the biota can respond or adapt.

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Concerted political attention has focused on reducing deforestation, and this remains the cornerstone of most biodiversity conservation strategies. However, maintaining forest cover may not reduce anthropogenic forest disturbances, which are rarely considered in conservation programmes. These disturbances occur both within forests, including selective logging and wildfires, and at the landscape level, through edge, area and isolation effects.

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As humans continue to alter tropical landscapes across the world, it is important to understand what environmental factors help determine the persistence of biodiversity in modified ecosystems. Studies on well-known taxonomic groups can offer critical insights as to the fate of biodiversity in these modified systems. Here we investigated species-specific responses of 44 forest-associated bird species with different behavioural traits to forest disturbance in 171 transects distributed across 31 landscapes in two regions of the eastern Brazilian Amazon.

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Land-cover change and ecosystem degradation may lead to biotic homogenization, yet our understanding of this phenomenon over large spatial scales and different biotic groups remains weak. We used a multi-taxa dataset from 335 sites and 36 heterogeneous landscapes in the Brazilian Amazon to examine the potential for landscape-scale processes to modulate the cumulative effects of local disturbances. Biotic homogenization was high in production areas but much less in disturbed and regenerating forests, where high levels of among-site and among-landscape β-diversity appeared to attenuate species loss at larger scales.

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