A switch in keystone seed-dispersing ant genera between two elevations for a myrmecochorous plant, acacia terminalis

© 2016 Thomson et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. The dispersal capacity of plant species that rely on animals to disperse their seeds (biotic dispersal) can alter with changes to the populations of their keystone dispersal vectors. Knowledge on how biotic dispersal systems vary across landscapes allows better understanding of factors driving plant persistence. Myrmecochory, seed dispersal by ants, is a common method of biotic dispersal for many plant species throughout the world. We tested if the seed dispersal system of Acacia terminalis (Fabaceae), a known myrmecochore, differed between two elevations in the Greater Blue Mountains World Heritage Area, in southeastern Australia. We compared ant assemblages, seed removal rates of ants and other vertebrates (bird and mammal) and the dominant seed-dispersing ant genera. At low elevations (c. 200 m a.s.l) seed removal was predominantly by ants, however, at high elevation sites (c. 700 m a.s.l) vertebrate seed dispersers or seed predators were present, removing over 60% of seeds from experimental depots when ants were excluded. We found a switch in the keystone seed-dispersing ant genera from Rhytidoponera at low elevations sites to Aphaenogaster at high elevation sites. This resulted in more seeds being removed faster at low elevation sites compared to high elevation sites, however long-term seed removal rates were equal between elevations. Differences in the keystone seed removalist, and the addition of an alternate dispersal vector or seed predator at high elevations, will result in different dispersal and establishment patterns for A. terminalis at different elevations. These differences in dispersal concur with other global studies that report myrmecochorous dispersal systems alter with elevation

Oil and gas exploration and development in the Lake Eyre Basin: distribution and consequences for rivers and wetlands, including the Coongie Lakes Ramsar Site

Context. Altered flooding regimes and pollution threaten the world’s wetlands, including floodplains of the largely free-flowing rivers. Aims. We investigated the distribution of current and future oil and gas production and exploration on the floodplains of the Lake Eyre Basin. Methods. We compiled these data and their associated infrastructure across the basin floodplains, including the Coongie Lakes Ramsar Site. Key results. There were 831 oil and gas wells across the Lake Eyre Basin, predominantly (98.6%) on Cooper Creek floodplains, with 296 wells in the Coongie Lakes Ramsar Site, with 281 well pads, roads (870 km) and 440 storages. Only eight referrals occurred under the Environment Protection and Biodiversity Conservation Act 1999, despite potential Ramsar wetland impacts. Future oil and gas production licences, primarily unconventional gas production, covered ~2.91 × 106 ha (Cooper Creek), 0.63 × 106 ha (Diamantina) and 1.03 × 106 ha (Georgina) of the floodplains. Conclusions and implications. Oil and gas production and exploration disrupt flooding regimes, with pollution (spills and greenhouse gas emissions). Little rigorous environmental assessment existed to protect the Lake Eyre Basin rivers and Coongie Lakes Ramsar Site, despite state and Commonwealth legislation and policy for protection, which remain largely ineffective in controlling oil and gas development on this free-flowing river

Incorporating an iterative energy restraint for the Surface Energy Balance System (SEBS)

© 2017 Elsevier Inc. The Surface Energy Balance System (SEBS) has proven itself as an effective remotely sensed estimator of actual evapotranspiration (ETa). However, it has several vulnerabilities associated with the partitioning of the available energy (AE) at the land surface. We introduce a two stage energy restraint process into the SEBS algorithm (SEBS-ER) to overcome these vulnerabilities. The first offsets the remotely sensed surface temperature to ensure the surface to air temperature difference reflects AE, while the second stage uses a domain based image search process to identify and adjust the proportions of sensible (H) and latent (λE) heat flux with respect to AE. We effectively implemented SEBS-ER over 61 acquisitions over two Landsat tiles (path 90 row 84 and path 91 row 85) in south-eastern Australia that feature heterogeneous land covers. Across the two areas we showed that the SEBS-ER algorithm has: greater resilience to perturbed errors in surface energy balance algorithm inputs; significantly improved accuracy (p < 0.05) at two eddy covariance flux towers in heavily forested (RMSE 62.3 W m− 2, R2 0.879) and sub-alpine grassland (RMSE 33.2 W m− 2, R2 0.939) land covers; and greater temporal stability across 52 daily actual evapotranspiration (ETa) estimates compared to a temporally stable and independent ETa dataset. The energy restraint within SEBS-ER has reduced exposure to the complex errors and uncertainties within remotely sensed, meteorological, and land type SEBS inputs, providing more reliable and accurate spatially distributed ETa products

Learning consciousness in managing water for the environment, exemplified using Macquarie River and Marshes, Australia

Context: Ongoing learning is essential for freshwater ecosystem management, but there is limited documentation of successful integration into management. Aims: We aimed to increase learning-related understanding required for effective adaptive management of water for the environment, in water-stressed and contested river systems. Methods: We developed a learning approach (requisite learning) for managing water for the environment, demonstrated with real-world examples from the Macquarie River and Marshes, Australia. Key results: Four co-existing, interdependent learning types enable effective management of water for the environment: (1) 'adjusting routines', (2) 'adaptive assessment', (3) 'changing practice', and (4) 'transforming governance', exemplified by using management of water for the environment for the Macquarie River and Marshes. To enable and improve requisite learning, stakeholder social learning, and flexibility in governance arrangements, must develop. Conclusions: Ongoing learning is essential for effective adaptive management. Understanding what requisite learning is and how capacity can be improved, will help achieve outcomes required of managing water for the environment. Implications: Effective management of water for the environment is essential, transparently delivering environmental outcomes and accounting for decision-making. To do this, we need to improve explicit learning understanding by nurturing learning mandates and champions, fostering social learning, increasing flexibility in governance arrangements, and institutionalising learning

Scale, evidence, and community participation matter: lessons in effective and legitimate adaptive governance from decision making for Menindee Lakes in Australia’s Murray-Darling Basin

Rivers and their interdependent human communities form social-ecologically complex systems that reflect basin scale functionally but are often governed by spatially mismatched governance systems. Accounting for this complexity requires flexible adaptive governance systems supported by legitimacy in decision-making processes. Meaningful community dialogue, information exchange, transparency, and scientific rigor are essential to this process. We examined failings in the adaptive governance of the Menindee Lakes system, a major Australian wetland system on the Barka/Darling River of the Murray-Darling Basin. Ecological sustainability of the Menindee Lakes was a casualty of a top-down governance, driven by the New South Wales Government in pursuit of “water savings” for the Murray-Darling Basin, a large scale, federally influenced region. We used quantitative and qualitative methods to analyze long-term social-ecological impacts and stakeholder perceptions of adaptive governance. State and federal government agencies failed basic processes of adaptive governance, ignoring local environmental sustainability in pursuit of basin scale objectives at great cost to governments, communities, humans, and non-humans. This resulted in the development of an ineffective, technocratic solution that lacked community input, leading to a complete loss of support by local communities, including traditional owners. We emphasize the importance of elements of scale in adaptive governance projects, if such projects are going to be effective and legitimate with consequences of coarse commitments to large spatial scale political and environmental objectives

Impacts on fish transported in tube fishways

Experimental data and numerical predictions of steady and unsteady flow in a 4 m high, 86 mm internal diameter tube fishway were compared quantitatively, and reflected expected uncertainties characteristic of the experiments and flow hydraulics. We then measured the response of a neutrally-buoyant fluid sensor and the behaviour of live fish transported vertically within the tube fishway. Ten repeat tests using the sensor and tests with seventy individual live fish demonstrated transport with 100% reliability. No ill effects were observed over a post-test monitoring period for two species of Australian native fish (Australian bass (Percalates novemaculeata) and Silver perch (Bidyanus bidyanus)) or as a function of size of the Silver perch that can be related to their passage through the fishway. There may have been temporary bruising of a few of the largest Silver perch tested. The largest Silver perch averaged 137 mm in length. The spatial distributions of the inert sensor and fish relative to the moving front during the transport process were quantified. Consequently, the volumes of water required during each operational cycle to ensure reliable delivery of fish over vertical distances less than 4 m were determined. The sensor measurements indicated negligible interactions with straight pipe walls but exposure to significant accelerations at sharp bends. Further experiments with live fish are required to quantify the possible adverse effects of alternative pipe transition designs on animals transported through them. Safe transport of fish up to a fish length/tube fishway delivery diameter ratio of 1.6 is demonstrated

Threatened but not conserved: Flying-fox roosting and foraging habitat in Australia

Conservation relies upon a primary understanding of changes in a species' population size, distribution, and habitat use. Bats represent about one in five mammal species in the world, but understanding for most species is poor. For flying-foxes, specifically the 66 Pteropus species globally, 31 are classified as threatened (Vulnerable, Endangered, Critically Endangered) on the IUCN Red List. Flying-foxes typically aggregate in colonies of thousands to hundreds of thousands of individuals at their roost sites, dispersing at sunset to forage on floral resources (pollen, nectar, and fruit) in nearby environments. However, understanding of flying-fox roosting habitat preferences is poor, hindering conservation efforts in many countries. In this study, we used a database of 654 known roost sites of the four flying-fox species that occur across mainland Australia to determine the land-use categories and vegetation types in which roost sites were found. In addition, we determined the land-use categories and vegetation types found within the surrounding 25 km radius of each roost, representing primary foraging habitat. Surprisingly, for the four species most roosts occurred in urban areas (42-59%, n = 4 species) followed by agricultural areas (21-31%). Critically, for the two nationally listed species, only 5.2% of grey-headed and 13.9% of spectacled flying-fox roosts occurred in habitat within protected areas. Roosts have previously been reported to predominantly occur in rainforest, mangrove, wetland, and dry sclerophyll vegetation types. However, we found that only 20-35% of roosts for each of the four species occurred in these habitats. This study shows that flying-fox roosts overwhelmingly occurred within human-modified landscapes across eastern Australia, and that conservation reserves inadequately protect essential habitat of roosting and foraging flying-foxes

Operational field trialling of Felixer™ grooming traps for the control of feral cats in the Strzelecki Desert, Australia

Context Feral cats (Felis catus) have an impact on native wildlife populations around the world but are difficult to control because of their neophobic behaviours and preference for live prey over scavenging poisoned baits. Felixers™ address these challenges by squirting poison-gel directly onto feral cats, exploiting their fastidious oral grooming tendencies to facilitate poison ingestion. Aims This study trialled Felixers in a landscape-scale arid-ecosystem site to assess their capacity to sustainably manage cat populations in a semi-bounded in situ predator training area and to eradicate cat incursions into a feral-free safe haven. Specifically, the aims were to determine target specificity and firing rates; optimise installation sites to exploit cat behaviour and landscape features; assess the fate of individuals following Felixer interaction; and assess the overall cost, performance and efficacy of Felixers compared with conventional cat control methods. Methods Up to nine Felixers were simultaneously deployed across three trial periods, spanning 30 months (4,642 trap nights) in Sturt National Park in the Strzelecki Desert dunefields of Australia. Felixers were deployed within and outside of feral-free safe havens, at varying cat densities, with populations monitored through camera-trap activity indices and individual behaviour monitored through satellite tracking. Key results Felixers fired at 20.3–43.9% of cats that passed in front (292 of 1,144 cats), with the remainder failing to satisfy the discriminatory algorithm’s target criteria. The devices had 99.93% target specificity from 17,425 interactions with moving animals and objects. Overall cat activity was lower in a semi-bounded 10,400 ha landscape-scale area where Felixers were intensively used, relative to an adjacent unbounded area where no cat control was occurring, over a 12-month subset of the 30-month trial. Felixers also resolved one of two incursions by cats into a 2,000 ha safe haven. Optimisation of Felixer placement and upgrading of software drove improvements in technical reliability and target identification during the trial. Shortcomings included cost and high incidence of technical faults, causing significant downtime and requiring regular investment of field staff time for monitoring and resolution. Conclusions Felixers provide a safe tool for cat management and eradication at intensively managed conservation sites. Efficacy could be improved through reductions in cost and improvements in reliability. Implications Overall Felixers appear to be an effective tool for cat management, when used in an integrated approach

Using feathers to map continental‐scale movements of waterbirds and wetland importance

Abstract Waterbirds are highly mobile, moving over large distances to access resources. Although consistent migration routes are observed in highly seasonal and predictable environments, movement patterns to utilize ephemeral resources in dryland environments are largely unknown. This makes conservation planning and water policy challenging as the relative importance of widely dispersed wetlands is difficult to rank. We addressed this challenge by combining a citizen science project with the novel application of X‐ray fluorescence of feathers to detect continental scale movement of waterbirds using elemental signatures. By doing so, we gained important insight into the movements of 24 waterbird species, including the significance of the Murray–Darling basin as a key source of waterbirds across the continent. Our approach highlights the benefits of elemental signatures to identify key areas of habitat use and priorities for wetland management

Fragmentation by major dams and implications for the future viability of platypus populations

The evolutionarily unique platypus (Ornithorhynchus anatinus) has experienced major declines and extinctions from a range of historical and recent interacting human-mediated threats. Although spending most of their time in the water, platypuses can move over land. Nevertheless, uncertainties remain whether dams are barriers to movement, thus limiting gene flow and dispersal, essential to evolution and ecology. Here we examined disruption of gene flow between platypus groups below and above five major dams, matched to four adjacent rivers without major dams. Genetic differentiation (FST) across dams was 4- to 20-fold higher than along similar stretches of adjacent undammed rivers; FST across dams was similar to differentiation between adjacent river systems. This indicates that major dams represent major barriers for platypus movements. Furthermore, FST between groups was correlated with the year in which the dam was built, increasing by 0.011 every generation, reflecting the effects of these barriers on platypus genetics. This study provides evidence of gene flow restriction, which jeopardises the long-term viability of platypus populations when groups are fragmented by major dams. Mitigation strategies, such as building of by-pass structures and translocation between upstream and downstream of the dam, should be considered in conservation and management planning