ORCID Profile
0000-0003-3650-3374
Current Organisation
University of Western Australia
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Environmental Science and Management | Environmental Management | Conservation and Biodiversity | Freshwater Ecology
ANZSRC Socio-Economic Objective (SEO)
Expanding Knowledge in the Environmental Sciences | Ecosystem Assessment and Management of Fresh, Ground and Surface Water Environments | Water Allocation and Quantification |
Related Links
Publications
Context dependency of top-down and bottom-up effects in a Northern Australian tropical river
Publisher: University of Chicago Press
Date: 06-2015
DOI: 10.1086/681106
Towards deeper collaboration: stories of Indigenous interests, aspirations, partnerships and leadership in aquatic research and management
Publisher: Springer Science and Business Media LLC
Date: 05-10-2016
Distribution, demography and dispersal model of spatial spread of invasive plant populations with limited data
Publisher: Wiley
Date: 11-05-2015
Implications of water extraction on the low-flow hydrology and ecology of tropical savannah rivers: an appraisal for northern Australia
Publisher: University of Chicago Press
Date: 06-2015
DOI: 10.1086/681302
Correlates of grass-species composition in a savanna woodland in northern Australia
Publisher: CSIRO Publishing
Date: 2009
DOI: 10.1071/BT08120
Abstract: Environmental features associated with the distribution of grass species are poorly known in tropical savannas, particularly at smaller spatial scales. The present study aimed to determine the relative influence of 11 environmental characteristics on grass-species composition in a savanna woodland in northern Australia. Environmental characteristics relating to woody-vegetation structure and soil, plus the long-term (14-year) fire frequency, were documented along an environmental gradient and compared with grass-species composition. Differences in grass-species composition, as well as richness and evenness, were related to differences in vegetation structure and edaphic characteristics. In particular, grass-species composition was most strongly related to plant-available moisture, the density of woody plants in the midstorey (2.0–9.99 m height), and canopy and litter cover. Grass-species richness and evenness were extremely low in areas where midstorey density, canopy cover and litter cover were high, and where soil moisture content in the root zone of grasses was low. Differences in fire frequency also influenced grass-species composition, with areas that had experienced lower fire frequency during the previous 14 years having lower density of the annual grass Sorghum intrans (F.Muell. ex Benth.) and the perennial grass Heteropogon triticeus (R.Br.) Stapf, and increased dominance of the perennial Eriachne triseta Nees ex Steud. The results of the present study demonstrate a complex interplay between bottom-up environmental factors and top-down processes such as fire, as determinants of grass-species composition in tropical savannas.
Invasive Andropogon gayanus (Gamba grass) alters litter decomposition and nitrogen fluxes in an Australian tropical savanna
Publisher: Springer Science and Business Media LLC
Date: 15-09-2017
DOI: 10.1038/S41598-017-08893-Z
Abstract: The African grass Andropogon gayanus Kunth. is invading Australian savannas, altering their ecological and biogeochemical function. To assess impacts on nitrogen (N) cycling, we quantified litter decomposition and N dynamics of grass litter in native grass and A . gayanus invaded savanna using destructive in situ grass litter harvests and litterbag incubations (soil surface and aerial position). Only 30% of the A . gayanus in situ litter decomposed, compared to 61% of the native grass litter, due to the former being largely comprised of highly resistant A . gayanus stem. In contrast to the stem, A . gayanus leaf decomposition was approximately 3- and 2 - times higher than the dominant native grass, Alloteropsis semilata at the surface and aerial position, respectively. Lower initial lignin concentrations, and higher consumption by termites, accounted for the greater surface decomposition rate of A . gayanus . N flux estimates suggest the N release of A . gayanus litter is insufficient to compensate for increased N uptake and N loss via fire in invaded plots. Annually burnt invaded savanna may lose up to 8.2% of the upper soil N pool over a decade. Without additional inputs via biological N fixation, A . gayanus invasion is likely to diminish the N capital of Australia’s frequently burnt savannas.
Fire frequency and biodiversity conservation in Australian tropical savannas
Publisher: Wiley
Date: 04-2005
Indigenous-led responsible innovation: lessons from co-developed protocols to guide the use of drones to monitor a biocultural landscape in Kakadu National Park, Australia
Publisher: Informa UK Limited
Date: 04-05-2021
Environmental factors influencing the establishment, height and fecundity of the annual grass Sorghum intrans in an Australian tropical savanna
Publisher: Cambridge University Press (CUP)
Date: 30-03-2010
DOI: 10.1017/S0266467409990629
Abstract: Environmental factors influencing grass establishment and performance in tropical savannas are poorly understood, particularly in relation to disturbance. We describe a seed sowing experiment that examined the effects of fire regime, canopy cover and litter cover on the emergence, establishment, height and fecundity (seed production) of the regionally dominant annual grass Sorghum intrans in northern Australia. Establishment was significantly lower under the woody canopy compared with canopy gaps, and where seeds were sown on a layer of litter compared with bare soil. However, variation in fire regime had no significant effect on establishment or seed production. Additionally, a shade-house experiment was conducted to test the effects of litter on seedling emergence of S. intrans and six other grass species representative of the local flora ( Pseudopogonatherum contortum , Sorghum plumosum , Chrysopogon latifolius , Eriachne triseta , Heteropogon triticeus and Alloteropsis semialata ). All species showed reduced emergence when sown either above or below litter, compared with bare soil. Our results demonstrate the importance of the overstorey as a determinant of S. intrans abundance and savanna grass composition more generally, through its effect on establishment. The aversion of savanna grasses to litter (and S. intrans to canopy shading) supports the notion of savanna species being highly adapted to disturbance.
WEEDS & FERAL ANIMAL ISSUES & SOLUTIONS
Publisher: Wiley
Date: 08-2004
Predicting Novel Riparian Ecosystems in a Changing Climate
Publisher: Springer Science and Business Media LLC
Date: 26-06-2013
The response of benthic algal biomass to nutrient addition over a range of current speeds in an oligotrophic river
Publisher: University of Chicago Press
Date: 12-2012
DOI: 10.1899/11-163.1
Riparian Ecosystems in the 21st Century: Hotspots for Climate Change Adaptation?
Publisher: Springer Science and Business Media LLC
Date: 13-03-2013
Does the Redfield ratio infer nutrient limitation in the macroalga Spirogyra fluviatilis?
Publisher: Wiley
Date: 07-12-2007
Use of otolith chemistry and acoustic telemetry to elucidate migratory contingents in barramundi Lates calcarifer
Publisher: CSIRO Publishing
Date: 2017
DOI: 10.1071/MF16177
Abstract: Migration is a fundamental aspect of the life history of many fish and must be well understood for targeted conservation and management. We used acoustic telemetry and otolith 87Sr/86Sr analysis, in conjunction with annual ageing, to study intraspecific variation in barramundi Lates calcarifer migration in the Northern Territory, Australia. Acoustic transmitters were implanted into 25 barramundi (420–1010-mm total length (TL) median 510mm TL) from freshwater reaches of the South Alligator River and their movements tracked over years. 87Sr/86Sr transect analysis was also conducted on otoliths of 67 barramundi from the Daly, Mary, South Alligator and Roper rivers. Acoustic telemetry showed that most fish remained in fresh water across wet and dry seasons. Higher rates of movement occurred during the wet season and a minority of fish moved into the estuary during high flows. Otolith chemistry analyses revealed high ersity in salinity histories among in iduals. We integrated the telemetry and otolith chemistry data to examine migration as a function of the stage of sexual development, and have proposed a revised life history model that identifies three migratory contingents. We conclude that anthropogenic disturbance, including modified river hydrology, has the potential to alter the frequency of life history contingents in barramundi populations.
Discharge-driven flood and seasonal patterns of phytoplankton biomass and composition of an Australian tropical savannah river
Publisher: Springer Science and Business Media LLC
Date: 20-01-2017
Seedling recruitment of the exotic grass Andropogon gayanus (Poaceae) in northern Australia
Publisher: CSIRO Publishing
Date: 2005
DOI: 10.1071/BT03154
Abstract: Andropogon gayanus Kunth. (Gamba grass), a tall perennial grass from Africa, is invading savanna ecosystems in northern Australia. This study investigated A. gayanus recruitment to determine the habitats at risk of invasion and to provide recommendations for its management. A. gayanus is able to establish and spread into new areas because of its high seed production (averaging 70 000 seeds m–2) and ability to establish across a range of habitats: from open woodlands on relatively dry lateritic soils to the more closed forests on black soil of the floodplain margins. Seedling emergence occurred in the absence of soil cultivation, although soil cultivation did increase emergence in the wetter habitats (Melaleuca uplands and floodplain margins). Seedling survival was high in the savanna (~90%) but low in the wetter habitats owing to wet-season inundation. A seed longevity trial based on burying seed in the field and retrieving between 1 and 12 months after burial showed that less than 1% of seeds survived in the seedbank after 12 months. Effective control programs are needed immediately because of the vast area and range of habitats in northern Australia that could potentially be invaded by A. gayanus. Management that can limit site disturbance and seed production, and can incorporate follow-up control for one to two years, should be an important part of an A. gayanus control strategy.
Exotic grass invasion alters microsite conditions limiting woody recruitment potential in an Australian savanna
Publisher: Springer Science and Business Media LLC
Date: 26-04-2018
DOI: 10.1038/S41598-018-24704-5
Abstract: Andropogon gayanus Kunth. is a large African tussock grass invading Australia’s tropical savannas. Invasion results in more intense fires which increases the mortality rate of adult woody plants. Invasion may also affect community structure by altering the recruitment potential of woody plants. We investigated the effects of A . gayanus invasion on ground-level microclimate, and the carbon assimilation potential and recruitment potential of two Eucalyptus species. We compared microclimatic variables from the early wet-season and into the mid-dry season to coincide with the period of growth of A . gayanus . We assessed Eucalyptus recruitment by monitoring seedling establishment, growth and survival of experimentally sown seed, and estimating seedling density resulting from natural recruitment. A . gayanus invasion was associated with increased grass canopy height, biomass and cover. Following invasion, the understorey microclimate had significantly reduced levels of photon flux density, increased air temperatures and vapour pressure deficit. The conditions were less favourable for woody seedling with aboveground biomass of seedlings reduced by 26% in invaded plots. We estimated that invasion reduced daily carbon assimilation of woody seedlings by ~30% and reduced survivorship of Eucalyptus seedlings. Therefore, A . gayanus invasion reduces recruitment potential, contributing to the transformation of savanna to a grassland ecosystem.
Consumer–resource coupling in wet–dry tropical rivers
Publisher: Wiley
Date: 21-11-2011
DOI: 10.1111/J.1365-2656.2011.01925.X
Abstract: 1. Despite implications for top-down and bottom-up control and the stability of food webs, understanding the links between consumers and their diets remains difficult, particularly in remote tropical locations where food resources are usually abundant and variable and seasonal hydrology produces alternating patterns of connectivity and isolation. 2. We used a large scale survey of freshwater biota from 67 sites in three catchments (Daly River, Northern Territory Fitzroy River, Western Australia and the Mitchell River, Queensland) in Australia's wet-dry tropics and analysed stable isotopes of carbon (δ(13) C) to search for broad patterns in resource use by consumers in conjunction with known and measured indices of connectivity, the duration of floodplain inundation, and dietary choices (i.e. stomach contents of fish). 3. Regression analysis of biofilm δ(13) C against consumer δ(13) C, as an indicator of reliance on local food sources (periphyton and detritus), varied depending on taxa and catchment. 4. The carbon isotope ratios of benthic invertebrates were tightly coupled to those of biofilm in all three catchments, suggesting assimilation of local resources by these largely nonmobile taxa. 5. Stable C isotope ratios of fish, however, were less well-linked to those of biofilm and varied by catchment according to hydrological connectivity the perennially flowing Daly River with a long duration of floodplain inundation showed the least degree of coupling, the seasonally flowing Fitzroy River with an extremely short flood period showed the strongest coupling, and the Mitchell River was intermediate in connectivity, flood duration and consumer-resource coupling. 6. These findings highlight the high mobility of the fish community in these rivers, and how hydrological connectivity between habitats drives patterns of consumer-resource coupling.
Effects of the exotic macrophyte, para grass (Urochloa mutica), on benthic and epiphytic macroinvertebrates of a tropical floodplain
Publisher: Wiley
Date: 15-05-2003
Invasive Andropogon gayanus (gamba grass) is an ecosystem transformer of nitrogen relations in Australian savanna
Publisher: Wiley
Date: 09-2009
DOI: 10.1890/08-0265.1
Abstract: Invasion by the African grass Andropogon gayanus is drastically altering the understory structure of oligotrophic savannas in tropical Australia. We compared nitrogen (N) relations and phenology of A. gayanus and native grasses to examine the impact of invasion on N cycling and to determine possible reasons for invasiveness of A. gayanus. Andropogon gayanus produced up to 10 and four times more shoot phytomass and root biomass, with up to seven and 2.5 times greater shoot and root N pools than native grass understory. These pronounced differences in phytomass and N pools between A. gayanus and native grasses were associated with an altered N cycle. Most growth occurs in the wet season when, compared with native grasses, dominance of A. gayanus was associated with significantly lower total soil N pools, lower nitrification rates, up to three times lower soil nitrate availability, and up to three times higher soil ammonium availability. Uptake kinetics for different N sources were studied with excised roots of three grass species ex situ. Excised roots of A. gayanus had an over six times higher-uptake rate of ammonium than roots of native grasses, while native grass Eriachne triseta had a three times higher uptake rate of nitrate than A. gayanus. We hypothesize that A. gayanus stimulates ammonification but inhibits nitrification, as was shown to occur in its native range in Africa, and that this modification of the soil N cycle is linked to the species' preference for ammonium as an N source. This mechanism could result in altered soil N relations and could enhance the competitive superiority and persistence of A. gayanus in Australian savannas.
Soil seed banks confer resilience to savanna grass-layer plants during seasonal disturbance
Publisher: Elsevier BV
Date: 03-2010
DYNAMICS OF IN‐STREAM WOOD AND ITS IMPORTANCE AS FISH HABITAT IN A LARGE TROPICAL FLOODPLAIN RIVER
Publisher: Wiley
Date: 21-05-2012
DOI: 10.1002/RRA.2580
Scale relationships and linkages between woody vegetation communities along a large tropical floodplain river, north Australia
Publisher: Cambridge University Press (CUP)
Date: 08-12-2009
DOI: 10.1017/S0266467409990319
Abstract: Riparian vegetation varies according to hydrogeomorphic processes operating across different scales over two didmensions: transversely (across-stream) and longitudinally (parallel to stream). We tested the hypothesis that vegetation patterns reveal the scale and direction of underlying processes. We correlated patterns of dominant woody vegetation with environmental variables at 28 sites located within four geomorphologically distinct regions along the length of the South Alligator River catchment of Kakadu National Park, northern Australia. Across the catchment there existed a strong transverse boundary between upland savanna vegetation and two zones of riparian vegetation: Melaleuca -spp.-dominated closed-forest vegetation along stream channels and mixed open-woodland vegetation adjacent to closed forest. We surmise that there is hierarchic constraint on smaller-scale catchment processes due to fire incursion into the riparian zone and access to water during the dry season. Within the closed-forest zone, vegetation did not vary transversely, but did longitudinally. Riparian woodlands also varied longitudinally, but in the upper reaches varied independently of stream variables. By contrast, in the lower reaches woodland was strongly correlated with stream variables. The observed pattern of weak transverse linkages in headwaters but strong linkages in lower reaches is analogous to models developed for in-stream patterns and processes, particularly the river continuum and flood-pulse concepts.
Timing and causes of gully erosion in the riparian zone of the semi-arid tropical Victoria River, Australia: Management implications
Publisher: Elsevier BV
Date: 08-2016
Connectivity, habitat, and flow regime influence fish assemblage structure: Implications for environmental water management in a perennial river of the wet–dry tropics of northern Australia
Publisher: Wiley
Date: 08-06-2020
DOI: 10.1002/AQC.3347
Abstract: Environmental water management seeks to balance competing demands between the water needed to sustain human populations and their economic activities and that required to sustain functioning freshwater ecosystems and the species they support. It must be predicated on an understanding of the environmental, hydrological, and biological factors that determine the distribution and abundance of aquatic species. The Daly River of the wet–dry tropics of northern Australia consists of a perennially flowing main stem and large tributaries, as well as many small to large naturally intermittent tributaries, and associated off‐channel wetlands. Increased groundwater abstraction to support irrigated agriculture during the dry season threatens to reduce dry‐season flows that maintain perenniality and persistence of freshwater fishes. Fish assemblages were surveyed at 55 locations during the dry season over a 2‐year period with the goal of establishing the key landscape‐scale and local‐scale (i.e. habitat) drivers of fish species distribution. Longitudinal (upstream/downstream) and lateral (river/floodplain) gradients in assemblage structure were observed with the latter dependent on the position in the river landscape. Underlying these gradients, stream flow intermittency influenced assemblage composition, species richness, and body size distributions. Natural constraints to dispersal were identified and their influence on assemblage structure was also dependent on position within the catchment. Eight distinct assemblage types were identified, defined by differences in the abundance of species within five groups differing in functional traits describing body size, spawning requirements, and dispersal capacity. These functional groups largely comprised species widely distributed in northern Australia. The results of the study are discussed with reference to the environmental flow needs of the Daly River and other rivers of northern Australia. The findings may also be applied to environmental flow management in savannah rivers elsewhere.
Adding Fuel to the Fire: The Impacts of Non-Native Grass Invasion on Fire Management at a Regional Scale
Publisher: Public Library of Science (PLoS)
Date: 14-05-2013
Andropogon gayanus (Gamba Grass) Invasion Increases Fire-mediated Nitrogen Losses in the Tropical Savannas of Northern Australia
Publisher: Springer Science and Business Media LLC
Date: 05-12-2007
Body size drives allochthony in food webs of tropical rivers
Publisher: Springer Science and Business Media LLC
Date: 28-11-2016
DOI: 10.1007/S00442-016-3786-Z
Abstract: Food web subsidies from external sources ("allochthony") can support rich biological ersity and high secondary and tertiary production in aquatic systems, even those with low rates of primary production. However, animals vary in their degree of dependence on these subsidies. We examined dietary sources for aquatic animals restricted to refugial habitats (waterholes) during the dry season in Australia's wet-dry tropics, and show that allochthony is strongly size dependent. While small-bodied fishes and invertebrates derived a large proportion of their diet from autochthonous sources within the waterhole (phytoplankton, periphyton, or macrophytes), larger animals, including predatory fishes and crocodiles, demonstrated allochthony from seasonally inundated floodplains, coastal zones or the surrounding savanna. Autochthony declined roughly 10% for each order of magnitude increase in body size. The largest animals in the food web, estuarine crocodiles (Crocodylus porosus), derived ~80% of their diet from allochthonous sources. Allochthony enables crocodiles and large predatory fish to achieve high biomass, countering empirically derived expectations for negative density vs. body size relationships. These results highlight the strong degree of connectivity that exists between rivers and their floodplains in systems largely unaffected by river regulation or dams and levees, and how large iconic predators could be disproportionately affected by these human activities.
Bayesian network models for environmental flow decision making in the Daly River, Northern Territory, Australia
Publisher: Wiley
Date: 24-09-2010
DOI: 10.1002/RRA.1456
Testing the grass‐fire cycle: alien grass invasion in the tropical savannas of northern Australia
Publisher: Wiley
Date: 23-04-2003
Tracking the resource pulse: Movement responses of fish to dynamic floodplain habitat in a tropical river
Publisher: Wiley
Date: 26-12-2020
Abstract: Natural river floodplains are among the Earth's most biologically erse and productive ecosystems but face a range of critical threats due to human disturbance. Understanding the ecological processes that support bio ersity and productivity in floodplain rivers is essential for their future protection and rehabilitation. Fish assemblage structure on tropical river floodplains is widely considered to be driven by dispersal limitation during the wet season and by environmental filtering and interspecific interactions during the dry season. However, the in idual-level movement behaviours (e.g. site attachment, nomadism, homing) that regulate dispersal of fish on floodplains are poorly understood. We combined radiotelemetry and remote sensing to examine the movement behaviour of two large-bodied fishes (barramundi Lates calcarifer, forktail catfish Neoarius leptaspis) over the flood cycle in a tropical river-floodplain system in northern Australia to: (a) quantify movement responses in relation to dynamic habitat resources at a landscape scale and (b) determine the extent of spatial 'reshuffling' of in idual fish following the wet season. Both species altered their behaviour rapidly in response to changes in the availability and distribution of aquatic habitat, with most in iduals undertaking extensive movements (up to ~27 km from the tagging location) on the inundated floodplain during the wet season. Although there was considerable in idual variation in movement patterns, overall barramundi distributions closely tracked the extent of floodplain primary productivity, whereas catfish distributions were most closely associated with the extent of flooded area. Most in iduals of both species exhibited homing back to previously occupied dry season refugia during the wet-to-dry transition, even though other potential refugia were available in closer proximity to wet season activity areas. We postulate that homing behaviour modulates temporal variation in fish assemblage composition and abundance and limits the transfer of aquatic-derived energy and nutrients into terrestrial food webs by reducing fish mortality on drying floodplains. Our study demonstrates the importance of quantifying in idual-level behaviour across the three stages of dispersal (emigration, inter-patch movement, immigration) for our understanding of how animal movement influences energetic subsidies and other large-scale ecosystem processes.
Fish mediate high food web connectivity in the lower reaches of a tropical floodplain river
Publisher: Springer Science and Business Media LLC
Date: 09-10-2011
DOI: 10.1007/S00442-011-2148-0
Abstract: High levels of hydrological connectivity during seasonal flooding provide significant opportunities for movements of fish between rivers and their floodplains, estuaries and the sea, possibly mediating food web subsidies among habitats. To determine the degree of utilisation of food sources from different habitats in a tropical river with a short floodplain inundation duration (~2 months), stable isotope ratios in fishes and their available food were measured from three habitats (inundated floodplain, dry season freshwater, coastal marine) in the lower reaches of the Mitchell River, Queensland (Australia). Floodplain food sources constituted the majority of the diet of large-bodied fishes (barramundi Lates calcarifer, catfish Neoarius graeffei) captured on the floodplain in the wet season and for gonadal tissues of a common herbivorous fish (gizzard shad Nematalosa come), the latter suggesting that critical reproductive phases are fuelled by floodplain production. Floodplain food sources also subsidised barramundi from the recreational fishery in adjacent coastal and estuarine areas, and the broader fish community from a freshwater lagoon. These findings highlight the importance of the floodplain in supporting the production of large fishes in spite of the episodic nature and relatively short duration of inundation compared to large river floodplains of humid tropical regions. They also illustrate the high degree of food web connectivity mediated by mobile fish in this system in the absence of human modification, and point to the potential consequences of water resource development that may reduce or eliminate hydrological connectivity between the river and its floodplain.
The impact of fire on riparian vegetation in Australia's tropical savanna
Publisher: University of Chicago Press
Date: 12-2015
DOI: 10.1086/684074
Do upstream migrating, juvenile amphidromous shrimps, provide a marine subsidy to river ecosystems?
Publisher: Wiley
Date: 20-02-2017
DOI: 10.1111/FWB.12907
Fire tolerance of perennial grass tussocks in a savanna woodland
Publisher: Wiley
Date: 25-11-2010
Benthic algal resilience to frequent wet-season storm flows in low-order streams in the Australian tropical savanna
Publisher: University of Chicago Press
Date: 12-2014
DOI: 10.1086/678516
Does long-term fire exclusion in an Australian tropical savanna result in a biome shift? A test using the reintroduction of fire
Publisher: Wiley
Date: 12-04-2012
Does flood rhythm drive ecosystem responses in tropical riverscapes?
Publisher: Wiley
Date: 2015
DOI: 10.1890/14-0991.1.SM
Measuring benefits of protected area management: Trends across realms and research gaps for freshwater systems
Publisher: The Royal Society
Date: 05-11-2015
Abstract: Protected areas remain a cornerstone for global conservation. However, their effectiveness at halting bio ersity decline is not fully understood. Studies of protected area benefits have largely focused on measuring their impact on halting deforestation and have neglected to measure the impacts of protected areas on other threats. Evaluations that measure the impact of protected area management require more complex evaluation designs and datasets. This is the case across realms (terrestrial, freshwater, marine), but measuring the impact of protected area management in freshwater systems may be even more difficult owing to the high level of connectivity and potential for threat propagation within systems (e.g. downstream flow of pollution). We review the potential barriers to conducting impact evaluation for protected area management in freshwater systems. We contrast the barriers identified for freshwater systems to terrestrial systems and discuss potential measurable outcomes and confounders associated with protected area management across the two realms. We identify key research gaps in conducting impact evaluation in freshwater systems that relate to three of their major characteristics: variability, connectivity and time lags in outcomes. Lastly, we use Kakadu National Park world heritage area, the largest national park in Australia, as a case study to illustrate the challenges of measuring impacts of protected area management programmes for environmental outcomes in freshwater systems.
BIODIVERSITY RESEARCH: Turning up the heat: the impacts of Andropogon gayanus (gamba grass) invasion on fire behaviour in northern Australian savannas
Publisher: Wiley
Date: 16-08-2010
Seasonal changes in water quality and macrophytes and the impact of cattle on tropical floodplain waterholes
Publisher: CSIRO Publishing
Date: 2012
DOI: 10.1071/MF12114
Abstract: The present study indicates the critical role of hydrologic connectivity in floodplain waterholes in the wet–dry tropics of northern Australia. These waterbodies provide dry-season refugia for plants and animals, are a hotspot of productivity, and are a critical part in the subsistence economy of many remote Aboriginal communities. We examined seasonal changes in water quality and aquatic plant cover of floodplain waterholes, and related changes to variation of waterhole depth and visitation by livestock. The waterholes showed declining water quality through the dry season, which was exacerbated by more frequent cattle usage as conditions became progressively drier, which also increased turbidity and nutrient concentrations. Aquatic macrophyte biomass was highest in the early dry season, and declined as the dry season progressed. Remaining macrophytes were flushed out by the first wet-season flows, although they quickly re-establish later during the wet season. Waterholes of greater depth were more resistant to the effects of cattle disturbance, and seasonal flushing of the waterholes with wet-season flooding homogenised the water quality and increased plant cover of previously disparate waterholes. Therefore, maintaining high levels of connectivity between the river and its floodplain is vital for the persistence of these waterholes.
A life-history account ofMacrobrachium spinipes(Schenkel, 1902) (Cherabin) in a large tropical Australian River
Publisher: University of Chicago Press
Date: 06-2015
DOI: 10.1086/681526
FIRE ECOLOGY & MANAGEMENT
Publisher: Wiley
Date: 08-2004
Comparison of image and rapid field assessments of riparian zone condition in Australian tropical savannas
Publisher: Elsevier BV
Date: 03-2007
Temporal and spatial patterns in stream physicochemistry and insect assemblages in tropical lowland streams
Publisher: University of Chicago Press
Date: 03-2006
Making time for space: the critical role of spatial planning in adapting natural resource management to climate change
Publisher: Elsevier BV
Date: 08-2017
Impacts of detritivore diversity loss on instream decomposition are greatest in the tropics
Publisher: Springer Science and Business Media LLC
Date: 17-06-2021
DOI: 10.1038/S41467-021-23930-2
Abstract: The relationship between detritivore ersity and decomposition can provide information on how biogeochemical cycles are affected by ongoing rates of extinction, but such evidence has come mostly from local studies and microcosm experiments. We conducted a globally distributed experiment (38 streams across 23 countries in 6 continents) using standardised methods to test the hypothesis that detritivore ersity enhances litter decomposition in streams, to establish the role of other characteristics of detritivore assemblages (abundance, biomass and body size), and to determine how patterns vary across realms, biomes and climates. We observed a positive relationship between ersity and decomposition, strongest in tropical areas, and a key role of abundance and biomass at higher latitudes. Our results suggest that litter decomposition might be altered by detritivore extinctions, particularly in tropical areas, where detritivore ersity is already relatively low and some environmental stressors particularly prevalent.
Invasive plants in the floodplains of Australia’s Kakadu National Park
Publisher: Springer Netherlands
Date: 2013
Quantifying indicators of riparian condition in Australian tropical savannas: integrating high spatial resolution imagery and field survey data
Publisher: Informa UK Limited
Date: 13-11-2008
Importance of the natural flow regime to an amphidromous shrimp: a case study
Publisher: CSIRO Publishing
Date: 2017
DOI: 10.1071/MF16034
Abstract: Amphidromous shrimp inhabiting large river systems are thought to migrate downstream to hatch larvae close to the estuary or sea. Recent work on Macrobrachium spinipes in northern Australia challenged this hypothesis, with the discovery of abundant females in reproductive condition over 400km upstream. We investigated the early life history of M. spinipes by using a combination of field s ling, laboratory experiments and modelling. We determined the spatial and temporal production of larvae, larval salinity requirements, and, finally, the potential for transport of larvae to the estuary during the wet season. Larvae occurred in high abundances across a 400-km river reach. However, successful larval development was contingent on access, by drift, to saltwater within 7 days. This interval is longer than that found for the majority of hidromous shrimp species and we propose that larvae in the study river are able to successfully moult through the early stages in freshwater. Large, wet-season discharge events were critical for transporting larvae from all s led sites to the estuary. The present study confirmed the hidromous life history of M. spinipes, highlighted the importance of natural flows for maintaining existing populations and provided evidence of a novel type of hidromous life-history strategy.
Temporal variation in benthic primary production in streams of the Australian wet–dry tropics
Publisher: Springer Science and Business Media LLC
Date: 08-05-2015
Hydrological connectivity structures concordant plant and animal assemblages according to niche rather than dispersal processes
Publisher: Wiley
Date: 16-11-2012
DOI: 10.1111/FWB.12058
Temporal and spatial variation in strontium in a tropical river: Implications for otolith chemistry analyses of fish migration
Publisher: Canadian Science Publishing
Date: 04-2017
Abstract: Analysis of otolith strontium isotope ratios ( 87 Sr/ 86 Sr) is an increasingly utilized approach for studying fish migration. We analysed surface and ground water from the Daly River catchment in the wet–dry tropics of northern Australia over 2 years. Analyses of otolith 87 Sr/ 86 Sr ratios were also conducted for freshwater sooty grunter (Hephaestus fuliginosus) and the putatively diadromous diamond mullet (Liza ordensis). Spatial variation in freshwater 87 Sr/ 86 Sr was high (range: 0.71612–0.78059), and there was strong seasonality in water 87 Sr/ 86 Sr, with highest values in the wet season. Temporal variation in water 87 Sr/ 86 Sr ratios is attributed to seasonal patterns in surface runoff from geological formations with radiogenic compositions versus input from groundwater aquifers interacting with less radiogenic formations. Temporal variation in water 87 Sr/ 86 Sr ratios precluded robust inference on movement within fresh water for both species, although movement across salinity gradients by diamond mullet was clearly identified. We conclude that temporally and spatially replicated water Sr data should be a general requisite for studies that analyse otolith Sr ( 87 Sr/ 86 Sr, Sr/Ca, Sr/Ba) to make inferences about fish movement and migration.
River and wetland food webs in Australia's wet-dry tropics: general principles and implications for management
Publisher: CSIRO Publishing
Date: 2005
DOI: 10.1071/MF04084
Abstract: The tropical rivers of northern Australia have received international and national recognition for their high ecological and cultural values. Unlike many tropical systems elsewhere in the world and their temperate Australian counterparts, they have largely unmodified flow regimes and are comparatively free from the impacts associated with intensive land use. However, there is growing demand for agricultural development and existing pressures, such as invasive plants and feral animals, threaten their ecological integrity. Using the international literature to provide a conceptual framework and drawing on limited published and unpublished data on rivers in northern Australia, we have derived five general principles about food webs and related ecosystem processes that both characterise tropical rivers of northern Australia and have important implications for their management. These are: (1) the seasonal hydrology is a strong driver of ecosystem processes and food-web structure (2) hydrological connectivity is largely intact and underpins important terrestrial–aquatic food-web subsidies (3) river and wetland food webs are strongly dependent on algal production (4) a few common macroconsumer species have a strong influence on benthic food webs and (5) omnivory is widespread and food chains are short. The implications of these ecosystem attributes for the management and protection of tropical rivers and wetlands of northern Australian are discussed in relation to known threats. These principles provide a framework for the formation of testable hypotheses in future research programmes.
Tropical freshwater sciences: an overview of ongoing tropical research
Publisher: University of Chicago Press
Date: 06-2015
DOI: 10.1086/681257
Recovery of benthic primary producers from flood disturbance and its implications for an altered flow regime in a tropical savannah river (Australia)
Publisher: Elsevier BV
Date: 2017
The effect of three fire regimes on stream water quality, water yield and export coefficients in a tropical savanna (northern Australia)
Publisher: Elsevier BV
Date: 04-2000
Exotic grass invasions
Publisher: Wiley
Date: 03-2010
Fish response to the temporal hierarchy of the natural flow regime in the Daly River, northern Australia
Publisher: Wiley
Date: 11-08-2011
DOI: 10.1111/J.1095-8649.2011.03072.X
Abstract: In this study, relationships between flow variation across multiple temporal scales and the distribution and abundance of three fish species, western rainbowfish Melanotaenia australis, sooty grunter Hephaestus fuliginosus and barramundi Lates calcarifer were examined at eight s ling reaches in the Daly River, Northern Territory, Australia. Discharge was highly seasonal during the study period of 2006-2010 with a distinct wet-dry discharge pattern. Significant catchment-wide correlations were identified between species abundance and hydrologic variables across several scales describing the magnitude and variability of flow. A Bayesian hierarchical model which accounted for >80% of variation in abundances for all species and age classes (i.e. juvenile and adult), identified the extent to which the influence of short-term flow variation was dependent upon the historical flow regime. There were distinct ontogenetic differences in these relationships for H. fuliginosus, with variability of recent flows having a negative effect on juveniles which was stronger at locations with higher historical mean daily flow. Lates calcarifer also displayed ontogenetic differences in relationships to flow variation with adults showing a positive association with increase in recent flows and juveniles showing a negative one. The effect of increased magnitude of wet-season flows on M. australis was negative in locations with lower historical mean daily flow but positive in locations with higher historical mean daily flow. The results highlighted how interactions between multiple scales of flow variability influence the abundance of fish species according to their life-history requirements.
Does flood rhythm drive ecosystem responses in tropical riverscapes?
Publisher: Wiley
Date: 03-2015
DOI: 10.1890/14-0991.1
Abstract: Biotic communities are shaped by adaptations from generations of exposure to selective pressures by recurrent and often infrequent events. In large rivers, floods can act as significant agents of change, causing considerable physical and biotic disturbance while often enhancing productivity and ersity. We show that the relative balance between these seemingly ergent outcomes can be explained by the rhythmicity, or predictability of the timing and magnitude, of flood events. By analyzing biological data for large rivers that span a gradient of rhythmicity in the Neotropics and tropical Australia, we find that systems with rhythmic annual floods have higher-fish species richness, more stable avian populations, and elevated rates of riparian forest production compared with those with arrhythmic flood pulses. Intensification of the hydrological cycle driven by climate change, coupled with reductions in runoff due to water extractions for human use and altered discharge from impoundments, is expected to alter the hydrologic rhythmicity of floodplain rivers with significant consequences for both bio ersity and productivity.
Productivity and Connectivity in Tropical Riverscapes of Northern Australia: Ecological Insights for Management
Publisher: Springer Science and Business Media LLC
Date: 21-09-2016
Resource-use efficiency explains grassy weed invasion in a low-resource savanna in north Australia
Publisher: Frontiers Media SA
Date: 04-08-2015
Integrated cross-realm planning: A decision-makers' perspective
Publisher: Elsevier BV
Date: 11-2015
Seasonal spatial dynamics of floodplain macrophyte and periphyton abundance in the Alligator Rivers region (Kakadu) of northern Australia
Publisher: Wiley
Date: 24-06-2016
DOI: 10.1002/ECO.1757
Relationships of stream algal community structure to catchment deforestation in eastern Madagascar
Publisher: University of Chicago Press
Date: 06-2009
DOI: 10.1899/07-171.1
We like to listen to stories about fish: Integrating indigenous ecological and scientific knowledge to inform environmental flow assessments
Publisher: Resilience Alliance, Inc.
Date: 2014
Water velocity and groundwater upwelling influence benthic algal biomass in a sandy tropical river: implications for water-resource development
Publisher: Springer Science and Business Media LLC
Date: 14-01-2020
Environmental drivers of recruitment in a tropical fishery: Monsoonal effects and vulnerability to water abstraction.
Publisher: Wiley
Date: 10-04-2022
DOI: 10.1002/EAP.2563
Abstract: Fisheries and natural water resources across the world are under increasing pressure from human activity, including fishing and irrigated agriculture. There is an urgent need for information on the climatic/hydrologic drivers of fishery productivity that can be readily applied to management. We use a generalized linear mixed model framework of catch curve regression to resolve the key climatic/hydrological drivers of recruitment in Barramundi Lates calcarifer using biochronological (otolith aging) data collected from four river-estuary systems in the Northern Territory, Australia. These models were then used to generate estimates of the year class strength (YCS) outcomes of different water abstraction scenarios (ranging from 10% to 40% abstraction per season/annum) for two of the rivers in low, moderate, and high discharge years. Barramundi YCS displayed strong interannual variation and was positively correlated with regional monsoon activity in all four rivers. River-specific analyses identified strong relationships between YCS and several river-specific hydrology variables, including wet and dry season discharge and flow duration. Water abstraction scenario models based on YCS-hydrology relationships predicted reductions of >30% in YCS in several cases, suggesting that increased water resource development in the future may pose risks for Barramundi recruitment and fishery productivity. Our study demonstrates the importance of the tropical monsoon as a driver of Barramundi recruitment and the potential for detrimental impacts of increased water abstraction on fishery productivity. The biochronological and statistical approaches we used have the potential to be broadly applied to inform policy and management of water resource and fisheries.
Productivity, Disturbance and Ecosystem Size Have No Influence on Food Chain Length in Seasonally Connected Rivers
Publisher: Public Library of Science (PLoS)
Date: 12-06-2013
Floodplain inundation and vegetation dynamics in the Alligator Rivers region (Kakadu) of northern Australia assessed using optical and radar remote sensing
Publisher: Elsevier BV
Date: 05-2014
The effect of a wildfire on stream water quality and catchment water yield in a tropical savanna excluded from fire for 10 years (Kakadu National Park, North Australia)
Publisher: Elsevier BV
Date: 07-2004
Related Organisations
Related Funding Activities
Linkage Projects - Grant ID: LP150100388
Start Date: 02-2016
End Date: 12-2020
Amount: $353,806.00
Funder: Australian Research Council
View Funded Activity