ORCID Profile
0000-0002-4797-5644
Current Organisation
UNSW Sydney
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Publisher: Wiley
Date: 05-07-2016
DOI: 10.1111/EMR.12220
Publisher: Springer Science and Business Media LLC
Date: 09-10-2010
Publisher: Cambridge University Press
Date: 23-01-2014
Publisher: Cold Spring Harbor Laboratory
Date: 20-06-2022
DOI: 10.1101/2022.06.17.496658
Abstract: Upland sw s are peat-accumulating, groundwater-dependent and fire-prone wetland ecosystems. Drying caused by anthropogenic processes such as underground mining, ditching and climate change may disrupt surface and groundwater flows effecting a bottom-up control on wetland expression. Fire is an endogenous, recurring disturbance that drives a top-down consumptive force in many of these systems. When compounded with anthropogenic drying, fire may facilitate permanent community transitions. A dearth of ecological data and temporal lags have h ered our ability to predict risks associated with multiple disturbances in wetland plant communities. We collected intact wetland mesocosms from valley floors and lower slopes of four undisturbed sw sites. We transferred the mesocosms to a glasshouse and established three different soil moisture availability levels to simulate wetland drainage. After 20 months of the hydrological treatment, we simulated a fire event by sequentially applying biomass removal (clipping), heat and smoke to half of the mesocosms. We monitored species biomass, richness and composition over a 3.5-year time frame. We found evidence of a temporal lag in biomass response to low water availability and synergistic hydrological and fire effects on species richness. In unburnt conditions, richness declined with low water availability but was maintained under high and medium water availability. After simulated fire in medium water availability, however, richness also declined and converged with depauperate low water mesocosm richness. Representation by many obligate sw species declined in low compared with high water availability mesocosms over time, an effect that was lified by the fire treatment. Our evidence of lagged effects of hydrological change on wetland vegetation and compounding effects of fire should be considered in impact assessments, monitoring programs and ecosystem management to avoid irreversible wetland change in drying environments.
Publisher: Wiley
Date: 03-03-2009
Publisher: Elsevier BV
Date: 2007
Publisher: Springer Science and Business Media LLC
Date: 07-03-2013
DOI: 10.1007/S00442-013-2628-5
Abstract: Different arrival order scenarios of native functional groups to a site may influence both resource use during development and final community structure. Arrival order may then indirectly influence community resistance to invasion. We present a mesocosm experiment of constructed coastal dune communities that monitored biotic and abiotic responses to different arrival orders of native functional groups. Constructed communities were compared with unplanted mesocosms. We then simulated a single invasion event by bitou (Chrysanthemoides monilifera ssp. rotundata), a dominant exotic shrub of coastal communities. We evaluated the hypothesis that plantings with simultaneous representation of grass, herb and shrub functional groups at the beginning of the experiment would more completely sequester resources and limit invasion than staggered plantings. Staggered plantings in turn would offer greater resource use and invasion resistance than unplanted mesocosms. Contrary to our expectations, there were few effects of arrival order on abiotic variables for the duration of the experiment and arrival order was unimportant in final community invasibility. All planted mesocosms supported significantly more invader germinants and significantly less invader abundance than unplanted mesocosms. Native functional group plantings may have a nurse effect during the invader germination and establishment phase and a competitive function during the invader juvenile and adult phase. Arrival order per se did not affect resource use and community invasibility in our mesocosm experiment. While grass, herb and shrub functional group plantings will not prevent invasion success in restored communities, they may limit final invader biomass.
Publisher: Wiley
Date: 27-02-2012
Publisher: Wiley
Date: 21-11-2022
DOI: 10.1111/COBI.13995
Abstract: Insights into declines in ecosystem resilience and their causes and effects can inform preemptive action to avoid ecosystem collapse and loss of bio ersity, ecosystem services, and human well‐being. Empirical studies of ecosystem collapse are rare and h ered by ecosystem complexity, nonlinear and lagged responses, and interactions across scales. We investigated how an anthropogenic stressor could diminish ecosystem resilience to a recurring perturbation by altering a critical ecosystem driver. We studied groundwater‐dependent, peat‐accumulating, fire‐prone wetlands known as upland sw s in southeastern Australia. We hypothesized that underground mining (stressor) reduces resilience of these wetlands to landscape fires (perturbation) by diminishing groundwater, a key ecosystem driver. We monitored soil moisture as an indicator of ecosystem resilience during and after underground mining. After landscape fire, we compared responses of multiple state variables representing ecosystem structure, composition, and function in sw s within the mining footprint with unmined reference sw s. Soil moisture declined without recovery in sw s with mine subsidence (i.e., undermined), but was maintained in reference sw s over 8 years (effect size 1.8). Relative to burned reference sw s, burned undermined sw s showed greater loss of peat via substrate combustion reduced cover, height, and biomass of regenerating vegetation reduced postfire plant species richness and abundance altered plant species composition increased mortality rates of woody plants reduced postfire seedling recruitment and extirpation of a hydrophilic animal. Undermined sw s therefore showed strong symptoms of postfire ecosystem collapse, whereas reference sw s regenerated vigorously. We found that an anthropogenic stressor diminished the resilience of an ecosystem to recurring perturbations, predisposing it to collapse. Avoidance of ecosystem collapse hinges on early diagnosis of mechanisms and preventative risk reduction. It may be possible to delay or ameliorate symptoms of collapse or to restore resilience, but the latter appears unlikely in our study system due to fundamental alteration of a critical ecosystem driver. Efectos de las interacciones entre los estresantes antropogénicos y las perturbaciones recurrentes sobre la resiliencia y el colapso de los ecosistemas
Publisher: Elsevier BV
Date: 06-2021
Publisher: Elsevier BV
Date: 04-2007
Publisher: Public Library of Science (PLoS)
Date: 10-01-2017
Publisher: Elsevier BV
Date: 04-2018
Publisher: Wiley
Date: 05-07-2022
DOI: 10.1111/AEC.13215
Abstract: Human intervention through damming, ersion and extraction of water resources has created regulated dryland river systems. As a result, connectivity between river channels and floodplain wetlands has diminished. Wetland function is fundamentally linked to water availability: flooding exchanges water, nutrients, sediments and biota with the floodplain. Water allocation for environmental flows may mitigate wetland degradation following river regulation by improving hydrological connectivity between rivers and floodplain wetlands. We report the results (2014–15 to 2018–19) of a vegetation monitoring program in the Macquarie Marshes in north western New South Wales. As part of the long‐term program, we monitored semi‐permanent wetland (Water Couch ( Paspalum distichum ) grassland or sedgeland dominated) and River Red Gum ( Eucalyptus camaldulensis ) forest/woodland communities along with environmental and water resource availability predictors. During the five‐year period, we found linear and nonlinear responses of functional group abundance and species richness to the water year and to time since last inundation. We also found differences in species assemblages in response to the flow and flooding regime, particularly water year and inundation duration. These results indicated that wetlands continued to express dry and wet phase responses. We also observed a depressed response to the large 2016–17 flood event by a subset of semi‐permanent wetland sites that had not been inundated in 3 years, compared with sites that were more recently inundated. This result indicated that environmental water management, along with protection of natural inundation events, may improve the resilience of floodplain wetlands: increased hydrological connectivity may promote a stronger wetland response when floods occur. Our results indicate that inundation, in part comprised of managed environmental flows, is a primary driver of species assemblage and functional group representation in semi‐arid floodplain wetlands.
Publisher: CSIRO Publishing
Date: 2005
DOI: 10.1071/PC050233
Abstract: Plant invasions of natural systems threaten bio ersity and ecosystem processes across many biomes. Historically most plant invasions have been facilitated by human activities such as industry, transport and landscape modification. Consequently, both causes and management of weed invasion are dependent on human behaviour and management advice provided by ecologists needs to take account of this fact. This paper assesses current environmental weed control policy in Australia and asks: are government, land managers and the scientific community using available social levers to achieve optimal weed management? We do this by comparing aspects of weed policy with a generalized natural resource policy framework. Adequacy of issue characterization and policy framing are discussed with particular reference to public perceptions of the weed problem, policy scaling and defining policy principles and goals. The implementation of policy Instruments, including regulation, VOluntary incentives, education, Information, motivational instruments, property-right instruments and pricing mechanisms are reviewed. Limitations of current instruments and potential options to improve instrument effectiveness are discussed. Funding arrangements for environmental weed control are also reported: environmental weed invasion generally represents an external cost to economic markets which has resulted in relatively low funding levels for control operations. Finally, review and monitoring procedures in weed programmes and policy are addressed. Rigorous monitoring systems are important in effective, adaptive weed management where control techniques are continually refined to improve ecological outcomes. The utility of maintaining links between project outcomes and policy inputs along with methods of implementing appropriate monitoring are discussed.
Publisher: Wiley
Date: 08-02-2023
Abstract: Upland sw s are peat‐accumulating, groundwater‐dependent and fire‐prone wetland ecosystems. Drying caused by anthropogenic processes such as underground mining, ditching and climate change may disrupt surface and groundwater flows and result in bottom‐up controls on wetland expression. Fire is an endogenous, recurring disturbance that drives a top‐down consumptive force in many upland sw systems. When compounded with drying, fire may facilitate permanent community transitions. A dearth of ecological data and temporal lags have h ered our ability to predict risks associated with multiple disturbances in wetland plant communities. We collected intact wetland mesocosms from valley floors and lower slopes of four undisturbed sw sites. We transferred the mesocosms to a glasshouse and established three different soil moisture availability levels to simulate wetland drainage. After 20 months of the hydrological treatment, we simulated a fire event by sequentially applying biomass removal (clipping), heat and smoke to half of the mesocosms. We monitored species biomass, richness and composition over a 3.5‐year time frame. We found evidence of a temporal lag in biomass response to low water availability and synergistic hydrological and fire effects on species richness. In unburnt conditions, richness declined with low water availability but was maintained under high and medium water availability. After simulated fire under medium water availability, however, richness also declined and converged with depauperate low‐water mesocosm richness. Representation by many obligate sw species declined in low compared with high water availability mesocosms over time, an effect that was lified by the fire treatment. Synthesis . Our evidence of lagged effects of hydrological change on wetland vegetation and compounding effects of fire should be considered in impact assessments, monitoring programs and ecosystem management to avoid irreversible wetland change in drying environments.
Publisher: Wiley
Date: 12-08-2008
Publisher: Wiley
Date: 16-02-2017
DOI: 10.1002/EAP.1449
Abstract: Effective conservation requires an understanding not only of contemporary vegetation distributions in the landscape, but also cognizance of vegetation transitions over time with the goal of maintaining persistence of all states within the landscape. Using a state and transition model framework, we investigated temporal transitions over 31 years in species composition among five upland sw vegetation communities in southeastern Australia. We applied fuzzy clustering to document transitions across communities evaluated the resilience and resistance of communities to change and explored the relationship between ecosystem states and major environmental factors posited to structure the system. We also evaluated the predictive ability of an established vegetation dynamics model. We found that community composition remained stable or underwent reversible or directional transitions depending on the vegetation type. Wetter communities (Ti-tree thicket and Cyperoid heath) were more stable (i.e., resistant) while drier communities showed a greater propensity to transition (i.e., had lower resistance) under the observed disturbance regime (low variance fire intervals). The resilience of drier communities differed under this regime, with Banksia thicket showing reversible compositional change, while Restioid heath and Sedgeland showed directional change. In accord with an established conceptual model, we found that communities were distributed along a hydrological gradient. In addition, vegetation structure, along with light penetration to ground level, differentiated communities. However, internal dynamics of drier communities were complex: differences in fire regime (penultimate fire interval in 2014 and number of fires since 1965) were unable to predict differences in community membership among sites. Aspects of the fire regime are expected to be more important predictors if fire intervals vary more strongly among sites in the future. Fuzzy clustering of compositional data allows managers to track community transitions over time and facilitates planned interventions for conservation purposes.
No related grants have been discovered for Tanya Mason.