Amina Price

Improving ecological response monitoring of environmental flows.

AbstractEnvironmental flows are now an important restoration technique in flow-degraded rivers, and with the increasing public scrutiny of their effectiveness and value, the importance of undertaking scientifically robust monitoring is now even more critical. Many existing environmental flow monitoring programs have poorly defined objectives, nonjustified indicator choices, weak experimental designs, poor statistical strength, and often focus on outcomes from a single event. These negative attributes make them difficult to learn from. We provide practical recommendations that aim to improve the performance, scientific robustness, and defensibility of environmental flow monitoring programs. We draw on the literature and knowledge gained from working with stakeholders and managers to design, implement, and monitor a range of environmental flow types. We recommend that (1) environmental flow monitoring programs should be implemented within an adaptive management framework; (2) objectives of environmental flow programs should be well defined, attainable, and based on an agreed conceptual understanding of the system; (3) program and intervention targets should be attainable, measurable, and inform program objectives; (4) intervention monitoring programs should improve our understanding of flow-ecological responses and related conceptual models; (5) indicator selection should be based on conceptual models, objectives, and prioritization approaches; (6) appropriate monitoring designs and statistical tools should be used to measure and determine ecological response; (7) responses should be measured within timeframes that are relevant to the indicator(s); (8) watering events should be treated as replicates of a larger experiment; (9) environmental flow outcomes should be reported using a standard suite of metadata. Incorporating these attributes into future monitoring programs should ensure their outcomes are transferable and measured with high scientific credibility.

A Bayesian Belief Network Decision Support Tool for Watering Wetlands to Maximise Native Fish Outcomes.

Wetlands are productive and diverse habitats for native fish but can be highly degraded, particularly in the Murray-Darling Basin (MDB), south-eastern Australia. Wetland management requires tools and processes that facilitate the synthesis and application of knowledge for decisions concerning the allocation of environmental water to wetlands to improve environmental outcomes. This paper describes the development of a Decision Support Tool (DST), based on a Bayesian Network designed to provide the best available science and support adaptive management of environmental flows into wetlands. The DST predicts the probability of improvements in fish population health as defined by abundance, population structure and fish condition for introduced common carp and three native species of fish: carp gudgeon, Australian smelt, and golden perch. Model sensitivity and validation showed that fish response varied depending on model inputs, but that responses from the DST were an accurate reflection of fish responses in wetlands based on field data. Ultimately, the success of this DST is dependent on its adoption by wetland managers. Throughout the entire development process, adoption of the DST has been promoted through engagement with managers and subsequently, through initiatives to integrate it into current management initiatives.

Distribution of arsenic species in an open seagrass ecosystem: relationship to trophic groups, habitats and feeding zones

Environmental context Although arsenic occurs at high concentrations in many marine systems, the influencing factors are poorly understood. The arsenic content of sediments, detritus, suspended particles and organisms have been investigated from different trophic levels in an open seagrass ecosystem. Total arsenic concentrations and arsenic species were organism-specific and determined by a variety of factors including exposure, diet and the organism physiology. Abstract The distribution and speciation of arsenic within an open marine seagrass ecosystem in Lake Macquarie, NSW, Australia is described. Twenty-six estuarine species were collected from five trophic groups (autotrophs, suspension-feeders, herbivores, detritivores and omnivores, and carnivores). Sediment, detritus, epibiota and micro-invertebrates were also collected and were classified as arsenic source samples. There were no significant differences in arsenic concentrations between trophic groups and between pelagic and benthic feeders. Benthic-dwelling species generally contained higher arsenic concentrations than pelagic-dwelling species. Sediments, seagrass blades and detritus contained mostly inorganic arsenic (50–90 %) and arsenoribosides (10–26 %), with some methylarsonate (9.4–14.6 %) and dimethyarsinate (7.9–9.7 %) in seagrass blades and detritus. Macroalgae contained mostly arsenoribosides (40–100 %). Epibiota and other animals contained predominately arsenobetaine (63–100 %) and varying amounts of dimethyarsinate (0–26 %), monomethyarsonate (0–14.6 %), inorganic arsenic (0–2 %), trimethylarsenic oxide (0–6.6 %), arsenocholine (0–12 %) and tetramethylarsonium ion (0–4.5 %). It was concluded that arsenic concentrations and species within the organisms of the Lake Macquarie ecosystem are species-specific and determined by a variety of factors including exposure, diet and the physiology of the organisms.

Model development of a Bayesian Belief Network for managing inundation events for wetland fish

Wetlands are essential components of floodplain-river ecosystems that often suffer degradation due to river regulation. To this end, the application of environmental water is increasingly being seen as an important amelioration strategy. However, decisions regarding the delivery of water to maximise environmental benefits, including native fish population health, are complex and difficult. This paper describes the development of a Bayesian Belief Network (BBN) model as part of a Decision Support Tool for assessing inundation strategies to benefit native wetland fish. Separate, albeit closely related, BBNs were developed for three native (golden perch Macquaria ambigua, carp gudgeon Hypseleotris spp., Australian smelt Retropinna semoni) and one alien fish species (common carp Cyprinus carpio carpio). The model structure was based on a conceptualisation of the relationships between wetland habitats, hydrology and fish responses, with emphasis on the types of inundation activities undertaken by managers. Conditional probability tables for fish responses were constructed from expert opinion and the model was validated against field data. The predictive ability and sensitivity of the model reflected the inherent high variability in relationships between wetland characteristics, hydrology and fish responses, but was nonetheless able to address satisfactorily such complexities within a holistic framework. As the model was designed in conjunction with managers and evaluated by them, its application will be enhanced by on-going engagement between managers and scientists.

The role of dispersal and retention in the early life stages of shrimp in a lowland river

This study investigated the importance of dispersal and retention processes during early ontogeny for three caridean shrimp species that complete their entire life history in freshwater. Directional traps were used to examine the small-scale movement patterns of shrimp into and out of nursery habitat patches (slackwaters) in a small lowland river in southeastern Australia. Movement patterns provided evidence for two contrasting life history based dispersal and retention strategies. For the two smaller atyid species, Paratya australiensis and Caridina mccullochi, the majority of larvae remained within the slackwater in which they were hatched until the final stage of development, at which point dispersal, either among slackwaters or out of slackwaters to faster-flowing pool and run habitats, occurred. For the larger palaemonid species, Macrobrachium australiense, larvae were hatched into slackwaters and dispersal occurred predominately during the first stage of larval development and then decreased as deve...

Morphological, physiological and behavioural response patterns of carp gudgeon Hypseleotris spp. to food deprivation: implications for assessing health

Morphological (growth, Fultons condition factor), physiological (per cent dry mass, total lipid content) and behavioural (activity levels) response patterns of carp gudgeon Hypseleotris spp. were examined in response to food deprivation during a 56 day experiment. Considerable variability in the nature and magnitude of these response patterns was observed, suggesting that caution should be taken when interpreting changes in the health of small-bodied fishes based on individual response variables.