ORCID Profile
0000-0002-9215-3666
Current Organisation
Murdoch University
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Publisher: Wiley
Date: 10-03-2023
DOI: 10.1111/GCB.16650
Abstract: Climate change is altering hydrological cycles globally, and in Mediterranean (med‐) climate regions it is causing the drying of river flow regimes, including the loss of perennial flows. Water regime exerts a strong influence over stream assemblages, which have developed over geological timeframes with the extant flow regime. Consequently, sudden drying in formerly perennial streams is expected to have large, negative impacts on stream fauna. We compared contemporary (2016/17) macroinvertebrate assemblages of formerly perennial streams that became intermittently flowing (since the early 2000s) to assemblages recorded in the same streams by a study conducted pre‐drying (1981/82) in the med‐climate region of southwestern Australia (the Wungong Brook catchment, SWA), using a multiple before‐after, control‐impact design. Assemblage composition in the stream reaches that remained perennial changed very little between the studies. In contrast, recent intermittency had a profound effect on species composition in streams impacted by drying, including the extirpation of nearly all Gondwanan relictual insect species. New species arriving at intermittent streams tended to be widespread, resilient species including desert‐adapted taxa. Intermittent streams also had distinct species assemblages, due in part to differences in their hydroperiods, allowing the establishment of distinct winter and summer assemblages in streams with longer‐lived pools. The remaining perennial stream is the only refuge for ancient Gondwanan relict species and the only place in the Wungong Brook catchment where many of these species still persist. The fauna of SWA upland streams is becoming homogenised with that of the wider Western Australian landscape, as drought‐tolerant, widespread species replace local endemics. Flow regime drying caused large, in situ alterations to stream assemblage composition and demonstrates the threat posed to relictual stream faunas in regions where climates are drying.
Publisher: Wiley
Date: 23-03-2018
DOI: 10.1111/CONL.12447
Publisher: Wiley
Date: 07-06-2023
DOI: 10.1002/ECO.2566
Abstract: Crayfish perform important roles within freshwater ecosystems, including in regions where global warming is causing prolonged drying of waterbodies. However, little is known about responses of crayfish to habitat drying from both a behavioural and physiological perspective. We compared burrowing ability, survival and metabolism of the crayfish Cherax quinquecarinatus from a seasonal stream and a perennial stream. Burrowing ability and crayfish survival were quantified in a mesocosm experiment contrasting sediment type (sand vs. clay/sand mixture) and water regime. Aerobic scope, standard metabolic rate (SMR) and maximum metabolic rate (MMR) were also compared using intermittent flow respirometry. Crayfish from the seasonal stream showed limited burrowing ability but higher survival in the drying treatment, while the perennial stream crayfish burrowed strongly in the clay/sand sediment. Higher survival suggests that crayfish from seasonal streams might be physiologically better adapted to drying. Larger crayfish burrowed more proficiently, reaching the saturated hyporheic zone refuge in the clay/sand sediment treatment. SMR/MMR/aerobic scope did not differ between populations or respirometry runs however, SMR differed between in iduals, perhaps due to personality traits. There was a significant negative relationship between MMR/aerobic scope and weight. Sediment type may limit C. quinquecarinatus burrowing and persistence through drying. Crayfish populations did not differ in terms of metabolism however, crayfish from seasonal habitats may possess more efficient physiological adaptations to drying. This study highlights the need for greater research attention on the effects of climatic drying on both the behaviour and the physiology of species exposed to climate change.
Publisher: Springer Science and Business Media LLC
Date: 08-1996
DOI: 10.1007/BF00328458
Publisher: Springer Science and Business Media LLC
Date: 05-2015
Publisher: Wiley
Date: 2005
DOI: 10.1002/AQC.675
Publisher: CSIRO Publishing
Date: 2009
DOI: 10.1071/MF08350
Abstract: Willow removal followed by riparian revegetation is a widespread river restoration practice in Australia, but the ecological response to this has rarely been evaluated. We s led river macroinvertebrates from six sites each of three riparian vegetation types: revegetated (treatment), willow-dominated (control) and native forest (reference) in the Gellibrand River catchment during austral spring 2007 and autumn 2008, and measured temperature and light intensity. Revegetated sites varied in age from 1 to 8 years since restoration. Abundances of invertebrates were similar across vegetation types, but were higher during autumn. Macroinvertebrate assemblages at revegetated sites (regardless of age) and at willow-dominated sites showed little among-site variation compared with native forest sites, which showed high site-to-site variability. Water temperatures and light intensity were higher at revegetated sites where works had recently been completed and cooler in native forest sites and long-established revegetated sites. The reduced variability in macroinvertebrate communities among revegetated sites may result from their history as willow-dominated sites or from the disturbance created by willow removal. Either way, these results suggest that longer than 8 years is required before macroinvertebrate assemblages in restored stretches of stream show the variation that appears characteristic of natural sites.
Publisher: International Association of Astacology
Date: 31-12-2014
Publisher: CSIRO Publishing
Date: 2012
DOI: 10.1071/MF12095
Abstract: Some freshwater species aestivate to resist drying however, little is known about factors affecting post-aestivation survival. Climate change prolongs drying and may make short bursts of flow more frequent in southern Australian streams, thereby affecting aestivation success. The tolerance of larval Lectrides varians (Mosley) to drying was tested by inducing aestivation in dry or moist sediment and then re-immersing larvae and measuring survival and activity. Survival did not differ between in iduals that were continually immersed (78%) or aestivating on moist sediment (70.5%) after 16 weeks. Survival was significantly lower on dry sediment (29.3%). Furthermore, some larvae showed delayed responses to re-immersion 65% of in iduals showed activity within 4.5 h, whereas over 30% of larvae did not become active until 72 h after re-immersion. L. varians can survive extended periods (112 days) without surface water, showing a bimodal response to re-immersion that increases the likelihood of population persistence by enabling some larvae to remain aestivating during short-lived bursts of stream flow. L. varians populations will therefore be more robust to prolonged stream drying and short-lived flow events than are some other insect taxa, although as the duration of aestivation increases larval survivorship decreases, suggesting that there are limits to the flexibility of aestivation traits.
Publisher: Wiley
Date: 09-07-2009
Publisher: Wiley
Date: 12-2004
DOI: 10.1002/RRA.789
Publisher: CSIRO Publishing
Date: 1996
DOI: 10.1071/MF9960851
Abstract: Densities of benthic invertebrates were counted over several weeks before and after a small winter spate (15.5 times base flow) in two riffle types of contrasting architectural complexity in Mountain River, Tasmania. Complex benthic architecture reduced the impact of this spate on invertebrate densities over the short term (seven days). Longer-term recovery (several weeks) was unaffected by riffle architecture, with one of the riffles recovering much more slowly than the others. Refuges from small spates in Mountain River may exist in mid channel in complex boulder-cobble riffles. Within its temporal context, the effects of the spate on the study sites were of a similar magnitude to other unexplained population fluctuations.
Publisher: Wiley
Date: 02-07-2015
DOI: 10.1111/FWB.12630
Publisher: Wiley
Date: 14-07-2011
Publisher: Wiley
Date: 24-05-2021
DOI: 10.1111/GCB.15673
Abstract: Recent climate change is altering the timing, duration and volume of river and stream flows globally, and in many regions, perennially flowing rivers and streams are drying and switching to intermittent flows. Profound impacts on aquatic biota are becoming apparent, due in part to the strong influence of flow regime on the evolution of life history. We made predictions of life‐history responses for 13 common aquatic invertebrate species (four caddisflies, five mayflies, two stoneflies, a dragonfly and an hipod), to recent flow regime change in Australian mediterranean climate streams, based on historic studies in the same streams. Size distributions, phenology, voltinism and synchrony were compared, revealing five main responses. More than half of the species were restricted to perennially flowing streams and were absent from those that had switched to intermittent flows (including all four caddisfly species). These formerly common species are at risk of extinction as climate change progresses. Two mayfly species had ergent responses in voltinism and synchrony, and one relied on drought micro‐refuges to persist. One stonefly species changed development timing to suit the new flow regime, and the hipod species retreated to subterranean refuges. Two formerly common species were not detected at all during 2016–2017. In addition, a new mayfly species and a caddisfly species proliferated under new flow regimes, because they had life histories suited to brief hydroperiods. Importantly, previous life history rarely predicted species’ actual responses to climate‐driven flow regime change, raising doubts about the veracity of predictions based on species traits. This is because a species’ potential for flexible phenology or growth rate is not necessarily indicated by life‐history traits.
Publisher: Springer Science and Business Media LLC
Date: 08-2004
Publisher: Elsevier BV
Date: 07-2010
Publisher: Springer Science and Business Media LLC
Date: 12-10-2022
DOI: 10.1038/S41586-022-05318-4
Abstract: As the United Nations develops a post-2020 global bio ersity 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’ 1,2 . Advancing dual imperatives to conserve bio ersity and sustain ecosystem services requires reliable and resilient generalizations and predictions about ecosystem responses to environmental change and management 3 . Ecosystems vary in their biota 4 , service provision 5 and relative exposure to risks 6 , yet there is no globally consistent classification of ecosystems that reflects functional responses to change and management. This h ers progress on developing conservation targets and sustainability goals. Here we present the International Union for Conservation of Nature (IUCN) Global Ecosystem Typology, a conceptually robust, scalable, spatially explicit approach for generalizations and predictions about functions, biota, risks and management remedies across the entire biosphere. The outcome of a major cross-disciplinary collaboration, this novel framework places all of Earth’s ecosystems into a unifying theoretical context to guide the transformation of ecosystem policy and management from global to local scales. This new information infrastructure will support knowledge transfer for ecosystem-specific management and restoration, globally standardized ecosystem risk assessments, natural capital accounting and progress on the post-2020 global bio ersity framework.
Publisher: Wiley
Date: 27-10-2006
Publisher: Wiley
Date: 07-07-2023
DOI: 10.1111/AEC.13384
Abstract: Little is known about odonate ecology and phenology in warm mediterranean climates where most wetlands are intermittent. We identified variables associated with the presence, relative abundance, assemblage composition and body size of odonates in spring and summer, to understand the influence of intermittency and season. We hypothesized that size at eclosion would be smaller in seasonal wetlands in summer due to time stress caused by drying. Nymphs, exuviae and adults were s led in spring and summer from 22 intermittent and perennial suburban wetlands in south‐western Australia. Spatial and environmental variables within and between wetlands were measured and associated with adult and nymph distributions. Exuviae were collected to quantify size at eclosion. As in temperate perennial wetlands, wetland‐scale variables (submerged, emergent and terrestrial vegetation, water temperature) were most strongly associated with assemblage composition of adults and nymphs, but landscape‐scale variables (distance to nearest patch of native vegetation, distance to nearest large lake) were also associated with adult assemblages. Two abundant dragonfly ( Orthetrum caledonicum Libellulidae, Hemicordulia tau Hemicorduliidae) and one damselfly ( Xanthagrion erythroneurum Coenagrionidae) species emerged at smaller body sizes in summer than spring, but from both intermittent and perennial wetlands. Consequently, declining photoperiod and warmer summer temperatures, rather than wetland drying, probably caused reduced size at eclosion. Although the influence of vegetation, temperature and photoperiod on odonate assemblages appears similar in temperate and mediterranean climates, odonate phenology differs markedly. Fitness cost of emerging at a smaller adult size may be outweighed by the increased likelihood of successfully reaching emergence in drying waterbodies in summer. More field data on size at eclosion in warm climate regions, and laboratory experiments manipulating temperature and photoperiod, are needed to confirm the generality of patterns shown here.
Publisher: CSIRO Publishing
Date: 2010
DOI: 10.1071/MF09073
Abstract: Metastability may arise in rivers subject to multiple disturbance processes because external constraints to ecosystem change sustain the metastable state this has important implications for management, especially river restoration. The Glenelg River and its southern Australian landscape have been extensively studied by different researchers across many projects, and several restoration actions implemented across different reaches and spatial scales. Research involving erse researchers and projects over extended periods shows strengths such as flexibility in pursuing emerging research questions, increased regional capacity by facilitating research training, and the generation of broader perspectives on river management. We conclude that metastability is a likely state for rivers with multiple interacting disturbances in regions with Mediterranean-type climates. In such rivers, disrupted relationships between the physical environment and ecological processes are likely, such that habitat restoration might have limited effectiveness. Restoration practices that constitute a disturbance might also risk disrupting metastability, or their impact may be limited because metastability confers resistance to further disturbance. Restoration may be more effectively targeted at less-disturbed reaches where ecosystems have a greater capacity to respond. Similarly, restoration in disturbed reaches might be more effectively directed at supporting metastability in the face of landscape change, than attempting to restore antecedent conditions.
Publisher: Wiley
Date: 2007
DOI: 10.1002/RRA.1016
Publisher: Springer International Publishing
Date: 2016
Publisher: Springer Science and Business Media LLC
Date: 18-07-2013
Publisher: CSIRO Publishing
Date: 2011
DOI: 10.1071/MF10062
Abstract: In some arid, semi-arid or Mediterranean climate regions, increased water extraction combined with climate change will prolong periods of drought in non-perennial streams, but the effects on macroinvertebrate populations are poorly understood. Drought refuges allow species to survive drying but their use depends on species’ traits, and refuge availability depends on landscape structure. This review evaluates the utility of existing ecological concepts for predicting the role of drought refuges for sustaining bio ersity in non-perennial streams. We also suggest traits that may determine invertebrate species’ resistance or resilience to prolonged drying. Parts of the likely responses by populations to increased stream drying are described by existing ecological concepts, such as the biological traits of species and their interaction with the habitat templet, barriers to dispersal and metapopulation dynamics, the use of drought refuges, habitat fragmentation and population and landscape genetics. However, the limited knowledge of invertebrate life histories in non-perennial streams restricts our ability to use these concepts in a predictive manner. In particular, reach or pool occupancy by species cannot be accurately predicted, but such predictions are necessary for evaluating potential management actions such as the use of environmental flows to sustain drought refuges during dry periods.
Publisher: Elsevier BV
Date: 03-2012
Publisher: CSIRO Publishing
Date: 2017
DOI: 10.1071/MF15391
Abstract: Submerged plants are often abundant in lowland streams in agricultural landscapes, but little is known of their role in stream ecosystems compared to riparian vegetation. We investigated the importance of submerged macrophytes as a basal resource of food webs in stream reaches with good and poor riparian vegetation condition, using mixing model analysis with stable carbon and nitrogen isotopes. Epilithic periphyton and terrestrial detritus were important basal resources in good condition reaches, although where macrophytes were present they contributed to food webs. Higher assimilation of either the macrophyte Cycnogeton huegelii or conspicuous epiphytes on C. huegelii leaves was associated with poor riparian condition. Where Potamogeton ochreatus and Ottelia ovalifolia occurred in poor condition reaches, these macrophytes contributed moderately to the food web, but were probably of greater importance as substrates for epiphytic algae. Mixing models indicated invertebrates commonly had generalist feeding strategies, feeding on the most available resource at each reach. Thus, where riparian vegetation is limited, submerged macrophytes may support opportunistic consumers both directly and as a substrate for epiphytes, thereby partially compensating for the loss of allochthonous resources in lowland agricultural streams.
Publisher: Wiley
Date: 05-11-2008
Publisher: Wiley
Date: 05-02-2020
DOI: 10.1111/FWB.13479
Publisher: Elsevier BV
Date: 09-2011
Publisher: Wiley
Date: 10-07-2021
DOI: 10.1111/FWB.13794
Abstract: Climate change is altering hydrologic regimes globally. In the Mediterranean climate region of south‐western Australia (SWA), climate drying has caused many perennial streams to switch to intermittent flow regimes. Shifts in flow regime are expected to alter physical and biological processes in streams, including litter decomposition, which is the basis of detrital food webs. Decomposition of jarrah ( Eucalyptus marginata ) leaves and associated macroinvertebrates, were measured over 320 days in 2018–19 using leaf bags in four headwater streams in SWA. Two streams retained perennial reaches and two were formerly perennial streams that are now intermittent. Pre‐planned comparisons that formed a partial multiple before–after, control–impact design were used to compare the results to an experiment conducted in 1982–83 in some of the same streams when all were perennially flowing. Both experiments used coarse and fine‐mesh bags containing 10 g of dry leaves. In one perennial stream, coarse bags lost more weight than fine bags at the last s ling time only, when shredding caddisflies arrived on the leaf bags. In the other perennial stream, leaf‐mining chironomids entered fine‐mesh bags and accelerated decomposition so that they lost more weight than the coarse‐mesh bags. There was no difference in weight loss between fine and coarse‐mesh leaf bags in the two intermittent streams. In 2018–19, decomposition was slower in dry reaches of intermittent streams than in perennial reaches. Leaf weight loss increased with the resumption of flow in intermittent streams, so that by the end of the experiment, similar amounts of leaf weight had been lost in intermittent and perennial reaches. Thus, although the temporal pattern of decomposition differed between intermittent and perennial reaches, after 320 days, they had reached a similar endpoint. Over similar experimental duration, mean leaf weight remaining in perennial reaches at the end of the experiment did not differ between the 1982–83 study and 2018–19, showing that leaf decomposition had not changed in reaches that retained perennial flow. As mean leaf weight remaining also did not differ between intermittent and perennial streams in 2018–19, leaf decomposition was robust to flow regime change. However, since 1982–83, these streams have lost populations of shredding caddisflies and stoneflies, which were replaced by other shredders (e.g. leaf mining chironomids Stenochironomus sp.), showing that there was some redundancy amongst shredder species. As climate change progresses, drying flow regimes will become commonplace in Mediterranean (and other) climate regions globally. This study indicates that litter decomposition may be maintained as streams transition to intermittency although shredder species may change. However, the impact of shredding species on leaf decomposition varies amongst studies, so effects of the loss of shredder species sensitive to drying may also vary, and in some cases their loss may substantially alter ecosystem processes.
Publisher: Wiley
Date: 08-2009
Publisher: Springer Science and Business Media LLC
Date: 27-02-2016
Publisher: Wiley
Date: 06-06-2019
DOI: 10.1002/AQC.3112
Publisher: Springer Science and Business Media LLC
Date: 23-10-2015
Publisher: CSIRO Publishing
Date: 2009
DOI: 10.1071/MF08175
Abstract: Restoration works are carried out to alleviate human impacts and improve habitats within ecosystems. However, human impacts may also create new (anthropogenic) habitat for species to exploit. A dilemma arises when proposed restoration works would remove anthropogenic habitat and the assemblages it supports. Sediment input into the Glenelg River has formed tributary junction plug wetlands at confluences. Sand slug removal is proposed as part of river rehabilitation, but would also drain plug wetlands. We s led four plug wetland, four river run and three river pool sites to determine whether plug wetlands influence water quality and add to the bio ersity of macroinvertebrates in the Glenelg River. Water quality and macroinvertebrate ersity were similar in plug wetlands, river runs and river pools. Assemblages were distinct among all sites, regardless of type, so there was no characteristic ‘plug-wetland fauna’. Therefore, although removal of plug wetlands would not cause a dramatic loss of invertebrate bio ersity, it would destroy anthropogenic habitat that supports a similar range of species to natural habitats in a river subject to multiple degrading processes. Gains from rehabilitation should be weighed against the value of anthropogenic habitat and the extent of similar habitat lost elsewhere in the ecosystem.
Publisher: Wiley
Date: 05-11-2012
DOI: 10.1002/AQC.2304
Publisher: Elsevier
Date: 2017
Publisher: Wiley
Date: 2006
DOI: 10.1002/AQC.725
Publisher: CSIRO Publishing
Date: 11-11-2022
DOI: 10.1071/MF22005
Abstract: The sheltered environments of coastal embayments have played a vital role for humans for millennia and their resources have underpinned modern industrial development globally. Their effective management and restoration remains an enormous challenge, owing, in part, to lack of recognition of the threshold changes that occurred in many bays prior to scientific study (i.e. years ago). Advances in marine extraction technologies and increased clearing of catchments for agriculture and urbanisation in recent history (∼400 years) have resulted in profound physical, chemical and biological changes to these ecosystems. More recently, the integration of ecology, history, archaeology, economics and fisheries science have contributed to the emerging field of ‘marine historical ecology’ (MHE). The synthesis of information from these different disciplines can markedly improve knowledge of past ecosystem condition, thereby assisting managers to set realistic goals for environmental restoration to improve bio ersity and ecosystem function. This paper reviews historical knowledge of long-term environmental degradation processes in coastal embayments, summarising the wide range of methods and techniques used as evidence and providing ex les from around the world, thereby illustrating the need for longer time-frames of reference for contemporary restoration ecology.
Publisher: Wiley
Date: 12-2009
DOI: 10.1002/RRA.1226
Publisher: Springer Science and Business Media LLC
Date: 22-06-2016
Publisher: Public Library of Science (PLoS)
Date: 19-03-2014
Publisher: CSIRO Publishing
Date: 2000
DOI: 10.1071/MF00012
Abstract: Human use of stream flow for water supply may increase the duration and/or frequency of dry periods in intermittent streams, but there is little information on the effect of this change on in-stream flora or fauna. To predict the effects of dry periods on stream biota, it is necessary to understand the relative roles of various sources of recolonization. A transplant experiment was used to test the hypothesis that the dry residual algal biofilm on stones in intermittent streams is an important source of algal growth when the streams are re-wetted. Two sites were chosen, one on each of two intermittent streams in south-eastern Australia. Rocks at the sites differed in the amount of naturally occurring residual biofilm on them. Forty rocks were transplanted between the sites and counts of algal densities were made from s les taken one and five weeks after flow recommenced. At one of the sites, where the biofilm was dominated by Cyanobacteria, dry residual biofilm strongly influenced the developing algal community at both one and five weeks after flow recommenced. At the other site the influence of dry biofilm was limited after five weeks, implying that other sources of algal recolonization were influential there.
Publisher: CSIRO Publishing
Date: 2002
DOI: 10.1071/MF01222
Abstract: A method is described for making rapid in situ field measurements of riverbed topography over spatial scales of ≅1–10 m. This method uses rolling balls to make quick, accurate measurements of river-bed roughness at several spatial scales. Random s ling and replication generate multiple estimates of the fractal dimension (d) that can be used to test for significant differences in the complexity of riverbed architecture between habitat types and spatial scales.
Publisher: CSIRO Publishing
Date: 2005
DOI: 10.1071/MF04219
Abstract: The hymenosomatid crab Amarinus lacustris is abundant in some south-eastern Australian rivers however, little is known of its ecology. Patterns of habitat use by crabs in rivers may be affected by seasonal changes in river discharge. This study investigates population characteristics, timing of reproduction and patterns of habitat use by A. lacustris in five riffle and pool habitats from each of the Hopkins and Merri Rivers in south-west Victoria, Australia, s led over a twelve-month period. Distribution of Amarinus lacustris was similar between the two rivers, but log-linear modelling showed that there was a strong association between crab sex, habitat occupied and time of year because female A. lacustris showed a shift from riffle to pool habitats during March and April, coinciding with the non-gravid period of the year. Male crabs also showed a change in relative occurrence, occurring most often in riffles during winter–spring (July–November) but being equally common in both habitats in summer–autumn (January–May). These patterns are probably the result of the reproductive cycle of A. lacustris, which appears to show both ontogenetic and sex-related changes in habitat use during its life cycle, taking advantage of seasonal fluctuations in flow regime that may assist egg/larval development and dispersal.
Publisher: Elsevier BV
Date: 04-2013
Publisher: Wiley
Date: 09-10-2021
DOI: 10.1111/GCB.15890
Abstract: Many regions across the globe are shifting to more arid climates. For shallow lakes, decreasing rainfall volume and timing, changing regional wind patterns and increased evaporation rates alter water regimes so that dry periods occur more frequently and for longer. Drier conditions may affect fauna directly and indirectly through altered physicochemical conditions in lakes. Although many studies have predicted negative effects of such changes on aquatic bio ersity, empirical studies demonstrating these effects are rare. Global warming has caused severe climatic drying in southwestern Australia since the 1970s, so we aimed to determine whether lakes in this region showed impacts on lake hydroperiod, water quality, and α, β and γ ersity of lake invertebrates from 1998 to 2011. Seventeen lakes across a range of salinities were s led biennially in spring in the Wheatbelt and Great Southern regions of Western Australia. Multivariate analyses were used to identify changes in α, β and γ ersity and examine patterns in physicochemical data. Salinity and average rainfall partially explained patterns in invertebrate richness and assemblage composition. Climatic drying was associated with significant declines in lake depth, increased frequency of dry periods, and reduced α and γ ersity (γ declined from ~300 to ~100 taxa from 1998 to 2011 in the 17 wetlands). In contrast, β ersity remained consistently high, because each lake retained a distinct fauna. Mean α ersity per‐lake declined both in lakes that dried and lakes that did not dry out, but lakes which retained a greater proportion of their maximum depth retained more α ersity. Accumulated losses in α ersity caused the decline in γ ersity likely through shrinking habitat area, fewer stepping stones for dispersal and loss of specific habitat types. Bio ersity loss is thus likely from lakes in drying regions globally. Management actions will need to sustain water depth in lakes to prevent bio ersity loss.
Publisher: CSIRO Publishing
Date: 2014
DOI: 10.1071/MF13239
Abstract: When intermittent streams flow, benthic algae develop from both colonising propagules and regrowing dried biofilm. We aimed to determine whether colonisation processes influence algal densities and taxonomic composition beyond the period immediately following commencement of winter flows, and whether regulation modifies those processes, in the Victoria Range, Australia. Stones were placed in two unregulated streams, and upstream and downstream of weirs in three regulated streams, after dry biofilm was removed. Epilithic algae on treatment and control stones were collected after winter flows (12 weeks). Treatment effects were still apparent in one (unregulated) stream, but not in the other streams. Algal assemblages and densities upstream and downstream of weirs differed, but there was no systematic pattern among streams. In intermittent headwater streams, recolonisation processes may influence algal assemblages until spring but in most streams, the duration of influence will be shorter, depending on the assemblage composition in regrowth and refuges, which is also shaped by conditions during the previous flow season. If the effects of regulation depend on how idiosyncratic flow regimes and assemblage compositions influence recolonisation, they may be difficult to predict. Similarly, recovery trajectories for stream communities after drought will differ among streams, depending on whether biofilm can develop during potentially short seasonal flows.
Publisher: Wiley
Date: 03-1998
Publisher: CSIRO Publishing
Date: 2010
DOI: 10.1071/MF10048
Abstract: Patterns in macroinvertebrate assemblage structure detected across spatial scales in rivers vary among studies, and it is not clear whether methodological differences in s ling methods or differences between rivers are responsible. We aimed to separate the roles of microhabitats and s ling methods in determining patterns in macroinvertebrate assemblages across spatial scales in the Johanna River, south-eastern Australia. We hypothesised that less s le-to-s le variability in the structure of macroinvertebrate assemblages would be detected using a Sürber s ler than by scrubbing stones. However, Sürber s les were more variable than in idual stones, although invertebrate abundance did not differ. To examine the effect of habitat and substratum, we hypothesised that taxa richness, invertebrate abundance and s le variability would differ among leaf packs and stones. Variation among s les in taxa richness and abundance was higher among leaf packs than among cobbles, whereas variability in taxon composition was much higher among stones. Leaf packs in runs had four times as many taxa as did stones in riffles, and more in iduals. Leaf packs may therefore provide a more representative s le of the assemblage than do stones. Sürber s lers may randomly subs le riffle assemblages, inflating the s le-to-s le variability detected.
Publisher: Wiley
Date: 12-1999
Publisher: Wiley
Date: 22-09-2014
DOI: 10.1111/FWB.12451
Publisher: Wiley
Date: 12-1999
Publisher: Wiley
Date: 22-02-2016
DOI: 10.1111/FWB.12738
Publisher: Wiley
Date: 21-03-2020
DOI: 10.1002/AQC.3324
Publisher: Springer Science and Business Media LLC
Date: 09-11-2012
Publisher: Elsevier
Date: 2024
Publisher: Wiley
Date: 08-09-2018
DOI: 10.1002/AQC.2828
Publisher: Springer Science and Business Media LLC
Date: 23-02-2018
Publisher: Wiley
Date: 28-04-2005
Publisher: Elsevier BV
Date: 10-2013
Publisher: CSIRO Publishing
Date: 2018
DOI: 10.1071/MF15094
Abstract: Rotational burn management has been practiced for years in UK peatlands however, little information exists on its effects on streams. An experiment investigated effects of ash input on four UK headwater streams by depositing ash onto trays filled with natural stream substrata. Before the experiment, streambed s les (SS) were taken to describe ambient macroinvertebrate assemblages. Macroinvertebrate response after 21 days was compared among SS, low (50g), high (100g) and top-up (50g + 50g dosed twice) ash-addition treatments and control trays (0g ash addition). Additions increased tray ash-free dry mass (AFDM), and by the end of the experiment, some trays retained more ash than did others (F12,72=5.15, P .001). Macroinvertebrate assemblages differed among streams (r=0.84, P .001) and treatments (r=0.23, P .001). SS contained fewer shredders than did other treatments (range: r=0.35–0.52, P=0.005). A significant relationship was found between assemblages and environmental conditions (Spearmans rho: 0.203, P=0.001). Stream depth and AFDM showed strongest correlations with assemblages. Ash deposition affects macroinvertebrate assemblages when deposited onto streambeds. However, the high among-stream variation in assemblage composition typical of UK headwaters is a stronger source of variation, suggesting that the effect of deposition is reasonably small in these streams.
Publisher: Springer Science and Business Media LLC
Date: 10-05-2016
No related grants have been discovered for Belinda Robson.