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Published Research

PEER REVIEWED JOURNAL ARTICLES

Publications: Publications

March 14 2023, Marine and Freshwater Research

Plasticity of upper thermal limits of Australian Paratya spp. (Decapoda, Atyidae) and considerations of climate-change adaptation

Abstract

Context: The ability of ectothermic stream invertebrates to adapt to the predicted increases in mean and extreme stream temperatures is crucial to ensuring they continue to exist.


Aims: To examine the plasticity of thermal limits of Australian  Paratya spp. (Decapoda, Atyidae) from streams in eastern New South Wales (NSW). We hypothesised that the upper lethal temperature (ULT, as indicated by the median lethal temperature, LT50) would be higher for warm water-acclimated shrimp individuals than for winter-acclimatised shrimp individuals because of the importance of acclimatisation temperature.


Methods: Controlled experiments were undertaken to determine the ULT by using ramping assays for winter field-acclimatised and warm water laboratory-acclimated Paratya spp.

Key results: Warm water-acclimated shrimp individuals demonstrated a significantly higher LT50 of 36.1°C than did winter-acclimatised shrimp individuals at 34.6°C. Paratya spp. exhibited a limited plasticity for acclimation to warmer temperatures.


Conclusions: Results demonstrated the potential vulnerability of ectothermic stream invertebrates to climate change if stream temperatures increase as predicted and thermal thresholds are exceeded.


Implications: Understanding the ULT of stream invertebrates helps predict their ability to respond to temperature variability and response to climate change. Increasing resilience through target management of resorting riparian vegetation for shade and securing environmental flows may reduce the impacts of stream warming.


Keywords: acclimatisation, climate change, distribution, macroinvertebrates, plasticity, shrimp, stream temperature, thermal tolerance.

In peer review

Mixing Fire and Water: Consequences of High-Severity Wildfires for Riverine Ecosystems

Brendan G. Cox, Andrew J. Brooks, William Bovil, Catherine Leigh, Pauline F. Grierson, Ewen Silvester, Michael Reid, Mark Lintermans8, Ben J. Kefford, Ross M.Thompson, Alec Davie, Sarah Mika, Sally MaxwelL, Lisa J. Evans, and Ryan M. Burrows.

Abstract

Riverine ecosystems are among the most threatened ecosystems globally. Exposure to increased frequency and spatial extent of high-severity wildfires are amongst the most serious threats facing riverine ecosystems. High severity fires are increasingly being referred to as high-severity ‘megafires’.  The ecological consequences of these fires are poorly understood. Still, they may include effects on important riverine ecosystem functions, patterns in diversity across a range of scales and habitats, and their potential recovery trajectories. Here, we identify themes that provide a conceptual framework for understanding the consequences of high-severity wildfire on riverine ecosystems and their subsequent recovery. In particular, we illustrate how different aspects of the fire regime and the location of a fire can affect both the ecological responses and interactions among the terrestrial impacts and riverine ecosystem consequences. We highlight gaps in knowledge to motivate a hypothesis-driven research program focused on understanding ecosystem consequences and recovery in riverine ecosystems due to high-severity wildfires.


Keywords:  Megafire, climate change, water quality, biodiversity, ecosystem recovery

November, 2019 Ecological Indicators Volume 106

A comparison of macroinvertebrate-based indices for biological assessment of river health: A case example from the sub-tropical Richmond River Catchment in northeast New South Wales, Australia

Brendan Cox, Sue Oeding, and Kathryn Taffs,

ABSTRACT

Globally, river health is deteriorating due to increased anthropogenic pressures. Accurately assessing river health is crucial for the management of river resources with macroinvertebrates commonly used as biological indicators of ecological integrity. Complex biological data is made more straightforward using indices as they offer the ability to rapidly communicate complex science in a simple form. Management decisions are often based on the results of biological river health assessments, making the identification of the most appropriate, robust and sensitive macroinvertebrate-based index vital when undertaking catchment specific assessments. Selection of a macroinvertebrate-based index should rely on a scientific method rather than arbitrary selection criteria. This study aimed to compare the performance of several macroinvertebrate-based indices to identify the index or indices most appropriate to the Richmond River Catchment (RRC) in northern New South Wales, Australia. River health within the RRC is poor with a clear pollution gradient from upper to lower catchment sites. Six commonly used indices were calculated using family-level identification. The biological assessment supported the physicochemical results with a gradient in river health from upper to lower catchment. Family Richness and Family Richness Percent were assessed as the most usable indices. In studies that have restricted time, budget and expertise they will provide accurate but limited information on river health. SIGNAL2 was identified as the most valid index for assessing river health due to its overall sensitivity to changes in river health, and level of detail on anthropogenic impacts. The poor performance of the AUSRIVAS, EPT and BCI limits or precludes their use for river health assessment in the RRC. While this model for identification and selection of an appropriate macroinvertebrate-based index for catchment scale river health assessments was useful in this context, it needs to be improved with a larger dataset and a greater environmental gradient of river health to make a less subjective evaluation.

15 January, 2018. Journal of Environmental Management, Volume 206

The influence of land use in a highly modified catchment: Investigating the importance of scale in riverine health assessment

Oeding, S., Taffs, K.H., Cox, B., Reichelt-Brushett, A., Sullivan, C.


ABSTRACT

Globally, river health is deteriorating due to increased anthropogenic pressures. Accurately assessing river health is crucial for the management of river resources with macroinvertebrates commonly used as biological indicators of ecological integrity. Complex biological data is made more straightforward using indices as they offer the ability to rapidly communicate complex science in a simple form. Management decisions are often based on the results of biological river health assessments, making the identification of the most appropriate, robust and sensitive macroinvertebrate-based index vital when undertaking catchment specific assessments. Selection of a macroinvertebrate-based index should rely on a scientific method rather than arbitrary selection criteria. This study aimed to compare the performance of several macroinvertebrate-based indices to identify the index or indices most appropriate to the Richmond River Catchment (RRC) in northern New South Wales, Australia. River health within the RRC is poor with a clear pollution gradient from upper to lower catchment sites. Six commonly used indices were calculated using family-level identification. The biological assessment supported the physicochemical results with a gradient in river health from upper to lower catchment. Family Richness and Family Richness Percent were assessed as the most usable indices. In studies that have restricted time, budget and expertise they will provide accurate but limited information on river health. SIGNAL2 was identified as the most valid index for assessing river health due to its overall sensitivity to changes in river health, and level of detail on anthropogenic impacts. The poor performance of the AUSRIVAS, EPT and BCI limits or precludes their use for river health assessment in the RRC. While this model for identification and selection of an appropriate macroinvertebrate-based index for catchment scale river health assessments was useful in this context, it needs to be improved with a larger dataset and a greater environmental gradient of river health to make a less subjective evaluation.

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