ORCID Profile
0000-0001-7208-9700
Current Organisation
University of Tasmania
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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)
Global Change Biology | Ecological Applications | Other Biological Sciences | Plant Physiology | Management And Environment | Global Change Biology | Terrestrial Ecology | Ecological Impacts of Climate Change | Terrestrial Ecology | Surfacewater Hydrology | Ecology | Soil Sciences | Forestry Sciences | Crop and Pasture Production | Soil Biology | Soil Chemistry | Plant Biology | Nutrition And Physiology | Natural Resource Management | Evolutionary Impacts of Climate Change | Ecosystem Function | Population And Ecological Genetics | Carbon Sequestration Science | Crop and Pasture Biomass and Bioproducts | Agro-ecosystem Function and Prediction | Landscape Ecology |
ANZSRC Socio-Economic Objective (SEO)
Climate change | Biological sciences | Integration of farm and forestry | Land and water management | Expanding Knowledge in the Environmental Sciences | Native vegetation | Expanding Knowledge in the Biological Sciences | Sown Pastures (excl. Lucerne) | Forestry | Hardwood plantations | Land and water management | Remnant vegetation and protected conservation areas | Rehabilitation/reafforestation | Remnant vegetation and protected conservation areas | Mountain and High Country Soils | Mountain and High Country Flora, Fauna and Biodiversity | Expanding Knowledge in the Agricultural and Veterinary Sciences | Pasture, browse and fodder crops | Mountain and High Country Land and Water Management | Global climate change adaptation measures | Ecosystem Assessment and Management of Mountain and High Country Environments
Related Links
Publications
A water availability gradient reveals the deficit level required to affect traits in potted juvenile Eucalyptus globulus
Publisher: Oxford University Press (OUP)
Date: 10-01-2017
DOI: 10.1093/AOB/MCW266
Stability of Plant Defensive Traits Among Populations in Two Eucalyptus Species Under Elevated Carbon Dioxide
Publisher: Springer Science and Business Media LLC
Date: 02-2012
DOI: 10.1007/S10886-012-0071-4
Abstract: Plant secondary metabolites (PSMs) mediate a wide range of ecological interactions. Investigating the effect of environment on PSM production is important for our understanding of how plants will adapt to large scale environmental change, and the extended effects on communities and ecosystems. We explored the production of PSMs under elevated atmospheric carbon dioxide ([CO(2)]) in the species rich, ecologically and commercially important genus Eucalyptus. Seedlings from multiple Eucalyptus globulus and E. pauciflora populations were grown in common glasshouse gardens under elevated or ambient [CO(2)]. Variation in primary and secondary chemistry was determined as a function of genotype and treatment. There were clear population differences in PSM expression in each species. Elevated [CO(2)] did not affect concentrations of in idual PSMs, total phenolics, condensed tannins or the total oil yield, and there was no population by [CO(2)] treatment interaction for any traits. Multivariate analysis revealed similar results with significant variation in concentrations of E. pauciflora oil components between populations. A [CO(2)] treatment effect was detected within populations but no interactions were found between elevated [CO(2)] and population. These eucalypt seedlings appear to be largely unresponsive to elevated [CO(2)], indicating stronger genetic than environmental (elevated [CO(2)]) control of expression of PSMs.
Quantifying neighbour effects on tree growth: Are common ‘competition’ indices biased?
Publisher: Wiley
Date: 21-03-2023
Abstract: Interactions among neighbouring plants are key determinants of plant growth. To characterise the cumulative effect of all neighbours on the growth of a focal plant, neighbourhoods are often described by ‘competition’ indices. Common competition indices calculate the summed size of neighbour plants (focal‐independent index [FII]) whilst others include the summed ratio of the neighbour size relative to focal plant size (focal dependent). A frequently overlooked statistical artefact is that focal‐dependent indices (FDIs) may lead to biased estimates of neighbourhood effects on plant growth when growth is size dependent. Here, we conduct a literature search to determine the most common index types used to explain neighbour effects on tree growth. We then assess the ability of two common index types—focal dependent and focal independent—to correctly infer neighbourhood effects in (1) observations of tree growth in an experimental forest in south‐east Tasmania, Australia, and (2) an artificially created dataset where tree growth is unrelated to the neighbourhood. Both indices detected the competitive neighbourhood effect on tree growth observed in our own dataset but differed in their conclusion regarding neighbour effects in the simulated data. Despite the simulated dataset being generated so there was no relationship between tree growth and their neighbourhood, the FDI detected strong, competitive neighbourhood effects when intrinsic growth was incorrectly related to tree size. In contrast, when we considered the FII as the neighbourhood metric, we correctly did not detect any neighbourhood effects in the simulated data regardless of how size‐dependent growth was described. Synthesis . ‘Competition’ indices are a useful method to characterise the cumulative neighbourhood effect on plant growth however, we demonstrate that indices which include the size of the focal plant in their calculation can be biased by an inherent relationship between tree growth and initial size. Whilst this bias typically overstates the strength of competition in determining focal tree growth, we show that it can be mitigated by correctly describing intrinsic growth. We discuss the limitations of both index types, provide recommendations for performing statistical modelling and outline how to check for accurate neighbour inference.
Effect of limited water availability on foliar plant secondary metabolites of two Eucalyptus species
Publisher: Elsevier BV
Date: 09-2014
Density and assemblage influence the nature of the species richness?productivity relationship in Australian dry sclerophyll forest species
Publisher: Wiley
Date: 09-2015
DOI: 10.1111/AEC.12182
Flowering phenology in a species-rich temperate grassland is sensitive to warming but not elevated CO(2)
Publisher: Wiley
Date: 12-03-2008
DOI: 10.1111/J.1469-8137.2008.02419.X
Abstract: * Flowering is a critical stage in plant life cycles, and changes might alter processes at the species, community and ecosystem levels. Therefore, likely flowering-time responses to global change drivers are needed for predictions of global change impacts on natural and managed ecosystems. * Here, the impact of elevated atmospheric CO2 concentration ([CO2]) (550 micromol mol(-1)) and warming (+2 masculineC) is reported on flowering times in a native, species-rich, temperate grassland in Tasmania, Australia in both 2004 and 2005. * Elevated [CO2] did not affect average time of first flowering in either year, only affecting three out of 23 species. Warming reduced time to first flowering by an average of 19.1 d in 2004, acting on most species, but did not significantly alter flowering time in 2005, which might be related to the timing of rainfall. Elevated [CO2] and warming treatments did not interact on flowering time. * These results show elevated [CO2] did not alter average flowering time or duration in this grassland neither did it alter the response to warming. Therefore, flowering phenology appears insensitive to increasing [CO2] in this ecosystem, although the response to warming varies between years but can be strong.
Effects of forest management practices on a localised Tasmanian endemic plant, the trailing riceflower Pimelea filiformis Hook.f. (Thymelaeaceae)
Publisher: Informa UK Limited
Date: 2005
The impacts of leaf shape and arrangement on light interception and potential photosynthesis in southern beech (Nothofagus cunninghamii)
Publisher: CSIRO Publishing
Date: 2004
DOI: 10.1071/FP03211
Abstract: The impact of differences in leaf shape, size and arrangement on the efficiency of light interception, and in particular the avoidance of photoinhibition, are poorly understood. We therefore estimated light exposure of branches in the cool temperate rainforest tree, Nothofagus cunninghamii (Hook.) Oerst., in which leaf shape, size and arrangement vary systematically with altitude and geographic origin. Measurements of incident photosynthetic photon flux density (PPFD) were made in the laboratory at solar angles corresponding to noon at summer solstice, winter solstice and equinox on branches collected from a common garden experiment. Tasmanian plants showed more self-shading than Victorian plants in summer and equinox. This was related to branch angle, leaf arrangement and leaf shape. Using a modelled light response-curve, we estimated the carbon assimilation rate and the flux density of excess photons at different incident PPFD. Victorian plants had higher predicted assimilation rates than Tasmanian plants in summer and equinox, but were exposed to substantially greater levels of excess photons. Because of the shape of the light-response curve, self-shading appears to reduce the plant's exposure to excess photons, thus providing photoprotection, without substantially reducing the carbon assimilation rate. This is dependent on both regional origin and season.
Aridity drives coordinated trait shifts but not decreased trait variance across the geographic range of eight Australian trees
Publisher: Wiley
Date: 13-08-2020
DOI: 10.1111/NPH.16795
Abstract: Large intraspecific functional trait variation strongly impacts many aspects of communities and ecosystems, and is the medium upon which evolution works. Yet intraspecific trait variation is inconsistent and hard to predict across traits, species and locations. We measured within‐species variation in leaf mass per area (LMA), leaf dry matter content (LDMC), branch wood density (WD), and allocation to stem area vs leaf area in branches (branch Huber value (HV)) across the aridity range of seven Australian eucalypts and a co‐occurring Acacia species to explore how traits and their variances change with aridity. Within species, we found consistent increases in LMA, LDMC and WD and HV with increasing aridity, resulting in consistent trait coordination across leaves and branches. However, this coordination only emerged across sites with large climate differences. Unlike trait means, patterns of trait variance with aridity were mixed across populations and species. Only LDMC showed constrained trait variation in more xeric species and drier populations that could indicate limits to plasticity or heritable trait variation. Our results highlight that climate can drive consistent within‐species trait patterns, but that patterns might often be obscured by the complex nature of morphological traits, s ling incomplete species ranges or s ling confounded stress gradients.
Canopy damage during a natural drought depends on species identity, physiology and stand composition
Publisher: Wiley
Date: 14-12-2022
DOI: 10.1111/NPH.17888
Abstract: Vulnerability to xylem cavitation is a strong predictor of drought‐induced damage in forest communities. However, biotic features of the community itself can influence water availability at the in idual tree‐level, thereby modifying patterns of drought damage. Using an experimental forest in Tasmania, Australia, we determined the vulnerability to cavitation (leaf P 50 ) of four tree species and assessed the drought‐induced canopy damage of 2944 6‐yr‐old trees after an extreme natural drought episode. We examined how in idual damage was related to their size and the density and species identity of neighbouring trees. The two co‐occurring dominant tree species, Eucalyptus delegatensis and Eucalyptus regnans , were the most vulnerable to drought‐induced xylem cavitation and both species suffered significantly greater damage than neighbouring, subdominant species Pomaderris apetala and Acacia dealbata . While the two eucalypts had similar leaf P 50 values, E. delegatensis suffered significantly greater damage, which was strongly related to the density of neighbouring P. apetala . Damage in E. regnans was less impacted by neighbouring plants and smaller trees of both eucalypts sustained significantly more damage than larger trees. Our findings demonstrate that natural drought damage is influenced by in idual plant physiology as well as the composition, physiology and density of the surrounding stand.
The competitive effect of neighbouring plants on the growth of two eucalypts is stronger in dry conditions
Publisher: Wiley
Date: 26-10-2023
Responses to mild water deficit and rewatering differ among secondary metabolites but are similar among provenances within Eucalyptus species
Publisher: Oxford University Press (OUP)
Date: 23-10-2015
Abstract: Water deficit associated with drought can severely affect plants and influence ecological interactions involving plant secondary metabolites. We tested the effect of mild water deficit and rewatering on physiological, morphological and chemical traits of juvenile Eucalyptus globulus Labill. and Eucalyptus viminalis Labill. We also tested if responses of juvenile eucalypts to water deficit and rewatering varied within species using provenances across a rainfall gradient. Both species and all provenances were similarly affected by mild water deficit and rewatering, as only foliar abscisic acid levels differed among provenances during water deficit. Across species and provenances, water deficit decreased leaf water potential, above-ground biomass and formylated phloroglucinol compound concentrations, and increased condensed tannin concentrations. Rewatering reduced leaf carbon : nitrogen, and total phenolic and chlorogenic acid concentrations. Water deficit and rewatering had no effect on total oil or in idual terpene concentrations. Levels of trait plasticity due to water deficit and rewatering were less than levels of constitutive trait variation among provenances. The overall uniformity of responses to the treatments regardless of native provenance indicates limited ersification of plastic responses when compared with the larger quantitative variation of constitutive traits within these species. These responses to mild water deficit may differ from responses to more extreme water deficit or to responses of juvenile/mature eucalypts growing at each locality.
Soil carbon sequestration in cool temperate dryland pastures: mechanisms and management options
Publisher: CSIRO Publishing
Date: 2015
DOI: 10.1071/SR14062
Abstract: Permanent pastures, which include sown, native and naturalised pastures, account for 4.3 Mha (56%) of the national land use in Australia. Given their extent, pastures are of great interest with respect to their potential to influence national carbon (C) budgets and CO2 mitigation. Increasing soil organic C (SOC) mitigates greenhouse gases while providing other benefits such as pasture productivity, soil health and ecosystem services. Several management approaches have been recommended to increase C sequestration in pasture-based systems however, results have proved variable and often contradictory between sites and years. Here, we present an overview of the processes and mechanisms responsible for C sequestration in permanent pastures. In addition, we discuss the merits of traditional and emerging pasture-management practices for increasing SOC in pastures, with a focus on dryland pasture systems of south-eastern Australia. We conclude by summarising the knowledge gaps and research priorities for soil C-sequestration research in dryland pastures. Our review confirms that soils under a range of pasture types have considerable potential for sequestration of atmospheric CO2 in Australia, and that the magnitude of this potential can be greatly modified by pasture-management practices. Although the shortage of long-term studies under Australian conditions limits our ability to predict the potential of various management approaches to sequester soil C, our review indicates that prevention of erosion through maintenance of groundcover and adoption of options that promote deep C sequestration are likely to confer broad-scale maintenance or increases in SOC in pasture soils over a decade or longer. We acknowledge that the evidence is limited therefore, confidence in the recommended practices in different locations and climates is largely unknown.
Decomposition and nitrogen transformation rates in a temperate grassland vary among co-occurring plant species
Publisher: Springer Science and Business Media LLC
Date: 30-07-2011
Warming increases soil respiration in a carbon-rich soil without changing microbial respiratory potential
Publisher: Copernicus GmbH
Date: 02-09-2020
Exposure and Nutrients As Delimiters of Lichen Communities in Continental Antarctica
Publisher: Cambridge University Press (CUP)
Date: 11-1995
DOI: 10.1016/S0024-2829(95)80010-7
Abstract: Lichens dominate the terrestrial vegetation of the ice-free regions of continental Antarctica. Vegetation patterns were studied in the Windmill Islands Oasis, Wilkes Land, continental Antarctica, in relation to edaphic features to elucidate the factors that govern lichen distribution and abundance. Vegetation was studied on a low rounded knoll on Clark Peninsula some 3 km North East of the present Casey station. Substratum nutrient levels vary considerably across the knoll due to the presence of an abandoned penguin rookery on the crest and the uneven topography provides both sheltered and exposed sites. Along a 130 m-long transect crossing the knoll from South to North, a total of 25 species of lichen and one moss were identified, the vegetation being dominated by Umbilicaria decussata, Pseudephebe minuscula, Usnea sphacelata and U. antarctica . TWINSPAN analysis of species distributions identified six sociations, the distribution of which were related to substratum structure and chemistry. Several species were restricted to nutrient-rich zones while late-lying snow restricted all species to varying degrees.
Testing the impact of community composition on the productivity of a cool temperate eucalypt forest: the Australian Forest Evenness Experiment (AFEX)
Publisher: CSIRO Publishing
Date: 2020
DOI: 10.1071/BT19131
Abstract: Understanding the factors controlling productivity is crucial for modelling current and predicting future forest growth and carbon sequestration potential. Although abiotic conditions exert a strong influence on productivity, it is becoming increasingly evident that plant community composition can dramatically influence ecosystem processes. However, much of our understanding of these processes in forests comes from correlative studies or field experiments in short-statured, short-lived vegetation. Here, we present the background, design and implementation success of the Australian Forest Evenness Experiment (AFEX), which was designed to investigate the influence of community composition on the processes that contribute to forest productivity. Eighty 25 × 25-m plots, covering 5 ha in a logged, burnt forest coupe in south-eastern Tasmania were sown with four tree species, namely Eucalyptus delegatensis R.T.Baker, E. regnans F.Muell., Acacia dealbata Link and Pomaderris apetala Labill., in varying combinations to provide a range of evenness levels with each of the four species as target dominant. Despite some differences between sown composition and realised composition 1year after sowing, a substantial range of community evenness and local neighbourhood densities and compositions existed in the experiment. Thus, this site provides a unique opportunity to determine the influence of local neighbourhood composition on a range of ecological processes.
Occurrence and distribution of native and introduced C-4 grasses in Tasmania
Publisher: CSIRO Publishing
Date: 2002
DOI: 10.1071/BT01093
Abstract: Of the 137 species of grass considered native to Tasmania, only eight use the C4 photosynthetic pathway. There are also approximately 137 grass species considered as introduced to Tasmania and 21% of these are C4. In total, there are 41 species from 20 genera of C4 grass recorded from Tasmania. Many of the introduced C4 species have a very limited distribution, however, and are generally confined to urban areas and along roadsides. Overall, Tasmania has fewer C4 grasses than would be expected from climate alone and few of the C4 grass species are widely distributed or abundant. However, the proportion of grasses recorded from Tasmania that use the C4 pathway has been increasing for the past century and is still increasing. General distribution and habitat notes are provided for all C4 grasses known to be native or naturalised in Tasmania.
Partitioning direct and indirect effects reveals the response of water-limited ecosystems to elevated CO2
Publisher: Proceedings of the National Academy of Sciences
Date: 24-10-2016
Abstract: Elevated levels of atmospheric carbon dioxide affect plants directly by stimulating photosynthesis and reducing stomatal aperture. These direct effects trigger several more subtle, indirect effects via changes in soil moisture and plant structure. While such effects have been acknowledged, they have never been assessed quantitatively, partly due to the fact they are inseparable in field experiments. Here we show that the indirect effects of elevated CO 2 explain, on average, 28% of the total plant productivity response, and are almost equal to the size of direct effects on evapotranspiration. This finding has major implications for our mechanistic understanding of plant response to elevated CO 2 , forcing us to revisit the interpretation of experimental results as well as simulations of future productivity.
Holistic carbon planning for industrial parks: a waste-to-resources process integration approach
Publisher: Elsevier BV
Date: 09-2012
Plant responses to CO2 are a question of time
Publisher: American Association for the Advancement of Science (AAAS)
Date: 20-04-2018
Abstract: Long-term experiments show unexpected plant responses to elevated CO 2 concentrations
Offspring of plants exposed to elevated or ambient CO2 differ in their impacts on soil nitrification in a common garden experiment
Publisher: Elsevier BV
Date: 07-2013
Warming prevents the elevated CO2-induced reduction in available soil nitrogen in a temperate, perennial grassland
Publisher: Wiley
Date: 31-01-2008
Author Correction: Nitrogen and phosphorus constrain the CO2 fertilization of global plant biomass
Publisher: Springer Science and Business Media LLC
Date: 26-05-2020
Soil water potential does not affect leaf morphology or cuticular characters important for palaeo-environmental reconstructions in southern beech, Nothofagus cunninghamii (Nothofagaceae)
Publisher: CSIRO Publishing
Date: 2012
DOI: 10.1071/BT11286
Abstract: Leaf form is closely related to local prevailing abiotic conditions and thus the morphology of fossil and sub-fossil leaves is often used to reconstruct both historical and palaeo-environmental conditions. However, palaeo-environmental reconstruction is difficult because leaf form is controlled potentially by many interacting environmental factors such as temperature, CO2 concentration, light and water availability. We used a glasshouse trial to investigate the impact of water availability on the leaf and cuticle morphology of a species important for palaeo-environmental reconstruction, the southern beech, Nothofagus cunninghamii. We found that reducing soil water potential to –0.2 or –0.5 MPa had no impact on leaf form or cuticular characters, despite reducing leaf carbon assimilation and severely restricting plant growth. Although plant accession affected many leaf characters, there were few significant impacts of altitude of origin and no substantial interactions between altitude of origin and soil water potential. Thus, both cuticular and gross leaf morphology seem to be stable across a range of soil water potentials in this species, meaning that palaeo-environmental signals from this species are unlikely to be affected by changes in water availability.
Variability in precipitation seasonality limits grassland biomass responses to rising CO2: historical and projected climate analyses
Publisher: Springer Science and Business Media LLC
Date: 06-06-2018
The TasFACE climate-change impacts experiment: design and performance of combined elevated CO2 and temperature enhancement in a native Tasmanian grassland
Publisher: CSIRO Publishing
Date: 2006
DOI: 10.1071/BT04194
Abstract: The potential impacts of climate change on both natural and managed ecosystems are far-reaching and are only beginning to be understood. Here we describe a new experiment that aims to determine the impacts of elevated concentration of CO2 ([CO2]) and elevated temperature on a native Themeda–Austrodanthonia-dominated grassland ecosystem in south-eastern Tasmania. The experimental site contains 60 vascular plant species. The experiment combines the latest developments in free-air CO2 enrichment (FACE) technology with the use of infrared (IR) heaters to mimic environmental conditions expected to exist in the year 2050. The CO2 concentration in the FACE treatments is reliably maintained at 550 µmol mol–1 and leaf temperature is elevated by an average of 2.1°C by the IR treatment, with 1-cm soil temperature being elevated by 0.8°C. Measurements being made in the experiment cover plant ecophysiological responses, plant population dynamics and community interactions. Soil processes and ecosystem effects, including nutrient cycling and plant animal interactions, are also being investigated. Collaborations are invited from interested parties.
Importance of the Local Environment on Nutrient Cycling and Litter Decomposition in a Tall Eucalypt Forest
Publisher: MDPI AG
Date: 16-04-2019
DOI: 10.3390/F10040340
Abstract: The relative abundance of nitrogen-fixing species has been hypothesised to influence tree biomass, decomposition, and nitrogen availability in eucalypt forests. This prediction has been demonstrated in experimental settings (two-species mixtures) but is yet to be observed in the field with more realistically complex communities. We used a combination of (a) field measurements of tree-community composition, (b) s ling of soil from a subset of these sites (i.e., the local environment), and (c) a decomposition experiment of forest litter to examine whether there is a local-scale effect of the nitrogen-fixing Acacia dealbata Link (presence and abundance) on nitrogen availability, and whether increases in this essential nutrient led to greater biomass of the canopy tree species, Eucalyptus obliqua L’Hér. Average A. dealbata tree size was a significant predictor of forest basal area in 24 plots (12% deviance explained) and, when combined with average distance between trees, explained 29.1% variance in E. obliqua biomass. However, static patterns of local nitrogen concentration were unrelated to the presence or size of A. dealbata, despite our experiments showing that A. dealbata leaf litter controls decomposition rates in the soil (due to three times higher N). Such results are important for forest management in the context of understanding the timing and turnover of shorter-lived species like acacias, where higher N (through either litter or soil) might be better detected early in community establishment (when growth is faster and intraspecific competition more intense) but with that early signal subsequently dissipated.
Seasonal trends in nitrogen status of Antarctic lichens
Publisher: Oxford University Press (OUP)
Date: 10-2000
A meta-analysis of 1,119 manipulative experiments on terrestrial carbon-cycling responses to global change
Publisher: Springer Science and Business Media LLC
Date: 19-08-2019
DOI: 10.1038/S41559-019-0958-3
Abstract: Direct quantification of terrestrial biosphere responses to global change is crucial for projections of future climate change in Earth system models. Here, we synthesized ecosystem carbon-cycling data from 1,119 experiments performed over the past four decades concerning changes in temperature, precipitation, CO
The response of leaf morphology to irradiance depends on altitude of origin in Nothofagus cunninghamii
Publisher: Wiley
Date: 31-10-2006
DOI: 10.1111/J.1469-8137.2005.01585.X
Abstract: Leaf morphology varies reliably with increasing altitude in many species, and this is generally considered to be related to temperature. Changes in irradiance with elevation may confound any relationships between a morphological character and altitude, particularly if altitude of origin affects the response to irradiance. Here we describe the interaction between irradiance and altitude of origin on leaf morphology of Southern beech, Nothofagus cunninghamii. Cuttings from each of four altitudes were grown in a glasshouse under full sunlight or 50% shade, and leaf morphology was related to irradiance, altitude of origin and accession. There was a significant interaction between irradiance and altitude of origin for leaf length, width, thickness, area, weight, specific leaf area and stomatal density. There was no effect of altitude on leaf length to width ratio or stomatal index, nor was there an interaction between irradiance and altitude of origin for these variables. These results show that the altitude of origin of a plant has an overriding impact on the leaf morphological response to irradiance. This must be considered in climatic reconstructions.
Nature vs nurture in the leaf morphology of Southern beech, Nothofagus cunninghamii (Nothofagaceae)
Publisher: Wiley
Date: 23-12-2004
Catalytic activity evaluation of industrial Pd/C catalyst via gray-box dynamic modeling and simulation of hydropurification reactor
Publisher: Elsevier BV
Date: 2015
Warming and free-air CO2 enrichment alter demographics in four co-occurring grassland species
Publisher: Wiley
Date: 20-07-2007
DOI: 10.1111/J.1469-8137.2007.02170.X
Abstract: DOI: 10.1111/j.1469-8137.2007.02224.x Commentary p 235
Light as a key driver of freshwater biofouling surface roughness in an experimental hydrocanal pipe rig
Publisher: Informa UK Limited
Date: 31-05-2016
DOI: 10.1080/08927014.2016.1184255
Abstract: Biofouling in canals and pipelines used for hydroelectric power generation decreases the flow capacity of conduits. A pipeline rig was designed consisting of test sections of varying substrata (PVC, painted steel) and light levels (transparent, frosted, opaque). Stalk-forming diatoms were abundant in both the frosted and transparent PVC pipes but negligible in the painted steel and opaque PVC pipes. Fungi were slightly more abundant in the painted steel pipe but equally present in all the other pipes while bacterial ersity was similar in all pipes. Photosynthetically functional biofouling (mainly diatoms) was able to develop in near darkness. Different biological fouling compositions generated differing friction factors. The highest friction factor was observed in the transparent pipe (densest diatom fouling), the lowest peak friction for the opaque PVC pipe (lowest fouling biomass), and with the painted steel pipe (high fouling biomass, but composed of fungal and bacterial crusts) being intermediate between the opaque and frosted PVC pipes.
Nitrogen and phosphorus constrain the CO2 fertilization of global plant biomass
Publisher: Springer Science and Business Media LLC
Date: 12-08-2019
Elevated CO2 causes large changes to morphology of perennial ryegrass (Lolium perenne)
Publisher: CSIRO Publishing
Date: 2019
DOI: 10.1071/CP18569
Abstract: Plant morphology and architecture are essential characteristics for all plants, but perhaps most importantly for agricultural species because economic traits are linked to simple features such as blade length and plant height. Key morphological traits likely respond to CO2 concentration ([CO2]), and the degree of this response could be influenced by water availability however, this has received comparatively little research attention. This study aimed to determine the impacts of [CO2] on gross morphology of perennial ryegrass (Lolium perenne L.), the most widespread temperate pasture species, and whether these impacts are influenced by water availability. Perennial ryegrass cv. Base AR37 was grown in a well-fertilised FACE (free-air carbon dioxide enrichment) experiment in southern Tasmania. Plants were exposed to three CO2 concentrations (~400 (ambient), 475 and 550 µmol mol–1) at three watering-treatment levels (adequate, limited and excess). Shoot dry weight, height, total leaf area, leaf-blade separation, leaf size, relative water content and specific leaf area were determined, as well as shoot density per unit area as a measure of tillering. Plant morphology responded dramatically to elevated [CO2], plants being smaller with shorter leaf-blade separation lengths and smaller leaves than in ambient (control) plots. Elevated [CO2] increased tillering but did not substantially affect relative water content or specific leaf area. Water supply did not affect any measured trait or the response to elevated [CO2]. Observed impacts of elevated [CO2] on the morphology of a globally important forage crop could have profound implications for pasture productivity. The reductions in plant and leaf size were consistent across a range of soil-water availability, indicating that they are likely to be uniform. Elucidating the mechanisms driving these responses will be essential to improving predictability of these changes and may assist in breeding varieties suited to future conditions.
Photosynthesis of coppicing poplar clones in a free-air CO2 enrichment (FACE) experiment in a short-rotation forest
Publisher: CSIRO Publishing
Date: 2003
DOI: 10.1071/FP02233
Abstract: Photosynthetic capacity was assessed in coppices of three poplar clones (Populus alba L. genotype 2AS11, P. × euramericana (Dode) Guinier genotype I-214 and P. nigra L. genotype Jean Pourtet) growing in the POPFACE/EUROFACE free-air CO2 enrichment experiment in central Italy. Plants were grown either at an elevated CO2 concentration of 550 μmol mol–1 or in control conditions for 3 years and were then harvested and allowed to coppice. Plants were either fertilised with the addition of liquid fertiliser at a level of 212 kg N ha–1 year–1 or unfertilised after harvesting. No evidence was found of changes in the maximum Rubisco carboxylation rate (VCmax) and thus there was no photosynthetic downregulation caused by the FACE treatment in either P. × euramericana or P. nigra, but there was a marginally significant reduction in VCmax of fertilised P. alba (P .09). Carbon assimilation rates were significantly higher in FACE plants than control plants. Maximum carbon assimilation rate was stimulated by an average of 32.8% in these clones, with in idual stimulation values of 27.6% for P. alba, 32.1% for P. × euramericana and 49.5% for P. nigra. No significant interactions between the FACE and fertilisation treatments were found for any of the photosynthetic variables measured. The day respiration rate in leaves of P.�×�euramericana was significantly increased by FACE treatment, but it was unaffected in the other clones. This work shows that photosynthesis remains stimulated at elevated CO2 concentration in these plants following harvesting, although to a lesser extent than seen normally, which may be related to a reduction in sink strength.
Flowering, seed production and seed mass in a species-rich temperate grassland exposed to FACE and warming
Publisher: CSIRO Publishing
Date: 2007
DOI: 10.1071/BT07107
Abstract: Long-term effects of climate change on plant communities must be mediated by reproductive and recruitment responses of component species. From spring 2003 until autumn 2006, we monitored flowering and seed-production responses to free air CO2 enrichment (FACE) and 2°C warming in a species-rich, nutrient-poor southern temperate grassland, by using the TasFACE experiment. There were no effects of either FACE or warming on the proportion of species flowering in any year. Flowering, seed production and seed mass were not significantly affected by FACE, warming or their interaction in most species. Some species, however, did respond significantly to simulated global changes. These responses generally were not governed by life history, but there were two distinct trends. First, warming increased the proportion of the population that flowered in perennial grasses but not in other species types. Second, flowering and seed production of both perennial woody dicots responded strongly to the interaction of FACE and warming, with Bossiaea prostrata producing most seeds in warmed FACE plots and Hibbertia hirsuta producing the most in unwarmed FACE plots. FACE increased seed mass 4-fold in the perennial C3 grass Elymus scaber (P 0.01) but substantially reduced seed mass of the perennial C3 grass Austrodanthonia caespitosa (P 0.02) and the perennial forb Hypochaeris radicata (P 0.02), with the remainder of species unaffected. Our results indicate that warming and elevated CO2 had little effect on seed production in the temperate grassland ecosystem. The few significant affects there were, however, are likely to have substantial implications for community composition and structure.
Influence of warming on soil water potential controls seedling mortality in perennial but not annual species in a temperate grassland
Publisher: Wiley
Date: 02-09-2008
DOI: 10.1111/J.1469-8137.2008.02563.X
Abstract: In a water-limited system, the following hypotheses are proposed: warming will increase seedling mortality elevated atmospheric CO2 will reduce seedling mortality by reducing transpiration, thereby increasing soil water availability and longevity (i.e. whether a species is annual or perennial) will affect the response of a species to global changes. Here, these three hypotheses are tested by assessing the impact of elevated CO2 (550 micromol mol(-1) and warming (+2 degrees C) on seedling emergence, survivorship and establishment in an Australian temperate grassland from autumn 2004 to autumn 2007. Warming impacts on seedling survivorship were dependent upon species longevity. Warming reduced seedling survivorship of perennials through its effects on soil water potential but the seedling survivorship of annuals was reduced to a greater extent than could be accounted for by treatment effects on soil water potential. Elevated CO2 did not significantly affect seedling survivorship in annuals or perennials. These results show that warming will alter recruitment of perennial species by changing soil water potential but will reduce recruitment of annual species independent of any effects on soil moisture. The results also show that exposure to elevated CO2 does not make seedlings more resistant to dry soils.
Elevated CO2 does not stimulate carbon sink in a semi-arid grassland
Publisher: Wiley
Date: 04-01-2019
DOI: 10.1111/ELE.13202
Modelled effects of rising CO2 concentration and climate change on native perennial grass and sown grass-legume pastures
Publisher: Inter-Research Science Center
Date: 03-06-2010
DOI: 10.3354/CR00863
The impacts of rising CO2 concentrations on Australian terrestrial species and ecosystems
Publisher: Wiley
Date: 29-08-2010
Soil nitrogen cycle unresponsive to decadal long climate change in a Tasmanian grassland
Publisher: Springer Science and Business Media LLC
Date: 10-12-2019
DOI: 10.1007/S10533-019-00627-9
Abstract: Increases in atmospheric carbon dioxide (CO 2 ) and global air temperature affect all terrestrial ecosystems and often lead to enhanced ecosystem productivity, which in turn d ens the rise in atmospheric CO 2 by removing CO 2 from the atmosphere. As most terrestrial ecosystems are limited in their productivity by the availability of nitrogen (N), there is concern about the persistence of this terrestrial carbon sink, as these ecosystems might develop a progressive N limitation (PNL). An increase in the gross soil N turnover may alleviate PNL, as more mineral N is made available for plant uptake. So far, climate change experiments have mainly manipulated one climatic factor only, but there is evidence that single-factor experiments usually overestimate the effects of climate change on terrestrial ecosystems. In this study, we investigated how simultaneous, decadal-long increases in CO 2 and temperature affect the soil gross N dynamics in a native Tasmanian grassland under C3 and C4 vegetation. Our laboratory 15 N labeling experiment showed that average gross N mineralization ranged from 4.9 to 11.3 µg N g −1 day −1 across the treatment combinations, while gross nitrification was about ten-times lower. Considering all treatment combinations, no significant effect of climatic treatments or vegetation type (C3 versus C4 grasses) on soil N cycling was observed.
Soil carbon storage under simulated climate change is mediated by plant functional type
Publisher: Wiley
Date: 12-2010
The influence of temperature and genotype on the growth and stomatal morphology of southern beech, Nothofagus cunninghamii (Nothofagaceae)
Publisher: CSIRO Publishing
Date: 2001
DOI: 10.1071/BT01001
Abstract: Nothofagus cunninghamii (Hook.) Oerst. clones of five different genotypes from Mt Field National Park, Tasmania, were grown in controlled environment cabinets at daytime temperatures of 23 and 18°C. These temperatures approximate summer conditions in Tasmania at sea level and at about 700 m a.s.l., respectively. There was a significant effect of both temperature and genotype on plant height, but there was no interaction of these terms. Temperature also had a significant influence on plant leaf area and biomass. Plants grown at 23°C were significantly larger and allocated more biomass to leaf tissue than did those grown at 18°C. Importantly, temperature had no impact on the size of leaves, whether expressed as average weight per leaf or area per leaf, but these variables were strongly affected by genotype. Specific leaf area, stomatal density and stomatal index did not vary with either temperature or genotype. These results have implications for our understanding of altitudinal impacts on plant morphology and also for the interpretation of the fossil record, since temperature has little impact on leaf characters in this species.
Globally consistent influences of seasonal precipitation limit grassland biomass response to elevated CO2
Publisher: Springer Science and Business Media LLC
Date: 08-02-2019
DOI: 10.1038/S41477-018-0356-X
Abstract: Rising atmospheric carbon dioxide concentration should stimulate biomass production directly via biochemical stimulation of carbon assimilation, and indirectly via water savings caused by increased plant water-use efficiency. Because of these water savings, the CO
Photosynthesis does influence superoxide production in the ichthyotoxic alga Chattonella marina (Raphidophyceae)
Publisher: Oxford University Press (OUP)
Date: 11-2002
Seedling survivorship of temperate grassland perennials is remarkably resistant to projected changes in rainfall
Publisher: CSIRO Publishing
Date: 2012
DOI: 10.1071/BT12042
Abstract: Recruitment is central to the maintenance of any plant population, particularly in disturbed or drought-prone environments. Recruitment relies on both seedling emergence and subsequent survival to establishment, processes susceptible to changes in soil water potential. Here, we use an existing relationship between seedling survivorship and soil water potential from the TasFACE global change impacts experiment situated in Tasmanian grassland, elucidate relationships between rainfall and soil water potential, and then simulate seedling survivorship responses to potential changes in both the amount and seasonal distribution of precipitation. Annual rainfall was a poor predictor of survivorship, suggesting the importance of seasonal and daily distribution of rain in determining establishment patterns. Modelled seedling survivorship was remarkably resistant to declines in rainfall, with a rainfall reduction of 40% reducing survivorship only by ~10%. Reducing spring rainfall only markedly reduced seedling survivorship when the rain removed was not added to winter rainfall. Our results show that soil water recharge during winter is critical to seedling survivorship of perennial species at the study site. Providing rainfall regimes allow recharge to occur, seedling survivorship of perennial grassland species may be maintained despite large reductions in rainfall, indicating that these grassland species may have an inherent capacity that limits the impacts of reductions in rainfall.
Elevated CO2 and warming impacts on flowering phenology in a southern Australian grassland are related to flowering time but not growth form, origin or longevity
Publisher: CSIRO Publishing
Date: 2008
DOI: 10.1071/BT08142
Abstract: Flowering is a critical stage in plant life cycles, and changes in phenology might alter processes at the species, community and ecosystem levels. Therefore, likely flowering-time responses to global-change drivers are needed for predictions of global-change impacts on natural and managed ecosystems. Predicting responses of species to global changes would be simplified if functional, phylogenetic or biogeographical traits contributed substantially to a species’ response. Here we investigate the role of growth form (grass, graminoid, forb, subshrub), longevity (annual, perennial), origin (native, exotic) and flowering time in determining the impact of elevated [CO2] (550 μmol mol−1) and infrared warming (mean warming of +2°C) on flowering times of 31 co-occurring species of a range of species-types in a temperate grassland in 2004, 2005 and 2007. Warming reduced time to first flowering by an average of 20.3 days in 2004, 2.1 days in 2005 and 7.6 days in 2007 however, the response varied among species and was unrelated to growth form, origin or longevity. Elevated [CO2] did not alter flowering times neither was there any [CO2] by species-type interaction. However, both warming and elevated [CO2] tended to have a greater effect on later-flowering species, with time to first flowering of later-flowering species being reduced by both elevated [CO2] (P 0.001) and warming (P 0.001) to a greater extent than that of earlier-flowering species. These results have ramifications for our predictions of community and ecosystem interactions in native grasslands in response to global change.
Altitude of origin influences stomatal conductance and therefore maximum assimilation rate in Southern Beech, Nothofagus cunninghamii
Publisher: CSIRO Publishing
Date: 2000
DOI: 10.1071/PP99164
Abstract: Gas exchange measurements were made on saplings of Southern Beech, Nothofagus cunninghamii (Hook.) Oerst. collected from three altitudes (350, 780 and 1100 m above sea level) and grown in a common glasshouse trial. Plants were grown from cuttings taken 2 years earlier from a number of plants at each altitude in Mt Field National Park, Tasmania. Stomatal density increased with increasing altitude of origin, and stomatal con-ductance and carbon assimilation rate were linearly related across all s les. The altitude of origin influenced thestomatal conductance and therefore carbon assimilation rate, with plants from 780 m having a greater photosynthetic rate than those from 350 m. The intercellular concentration of CO2 as a ratio of external CO2 concentration (ci/ca) was similar in all plants despite the large variation in maximum stomatal conductance. Carboxylation efficiency was greater in plants from 780 m than in plants from 350 m. Altitude of origin has a strong influence on the photo-synthetic performance of N. cunninghamii plants even when grown under controlled conditions, and this influence is expressed in both leaf biochemistry (carboxylation efficiency) and leaf morphology (stomatal density).
Multifunctional redundancy: Impossible or undetected?
Publisher: Wiley
Date: 08-2023
DOI: 10.1002/ECE3.10409
Abstract: The ersity‐functioning relationship is a pillar of ecology. Two significant concepts have emerged from this relationship: redundancy, the asymptotic relationship between ersity and functioning, and multifunctionality, a monotonic relationship between ersity and multiple functions occurring simultaneously. However, multifunctional redundancy, an asymptotic relationship between ersity and multiple functions occurring simultaneously, is rarely detected in research. Here we assess whether this lack of detection is due to its true rarity, or due to systematic research error. We discuss how inconsistencies in the use of terms such as ‘function’ lead to mismatched research. We consider the different techniques used to calculate multifunctionality and point out a rarely considered issue: how determining a function's maximum rate affects multifunctionality metrics. Lastly, we critique how a lack of consideration of multitrophic, spatiotemporal, interactions and community assembly processes in designed experiments significantly reduces the likelihood of detecting multifunctional redundancy. Multifunctionality research up to this stage has made significant contributions to our understanding of the ersity‐functioning relationship, and we believe that multifunctional redundancy is detectable with the use of appropriate methodologies.
VENTILATION AND RESPIRATION IN ROOTS OF ONE-YEAR-OLD SEEDLINGS OF GREY MANGROVE AVICENNIA-MARINA (FORSK) VIERH
Publisher: Springer Science and Business Media LLC
Date: 1995
DOI: 10.1007/BF00029107
Warming and elevated CO2 combine to increase microbial mineralisation of soil organic matter
Publisher: Elsevier BV
Date: 06-2015
Evaluating carbon storage in restoration plantings in the Tasmanian Midlands, a highly modified agricultural landscape
Publisher: CSIRO Publishing
Date: 2015
DOI: 10.1071/RJ15070
Abstract: In recent years there have been incentives to reforest cleared farmland in southern Australia to establish carbon sinks, but the rates of carbon sequestration by such plantings are uncertain at local scales. We used a chronosequence of 21 restoration plantings aged from 6 to 34 years old to measure how above- and belowground carbon relates to the age of the planting. We also compared the amount of carbon in these plantings with that in nearby remnant forest and in adjacent cleared pasture. In terms of total carbon storage in biomass, coarse woody debris and soil, young restoration plantings contained on average much less biomass carbon than the remnant forest (72 versus 203 Mg C ha–1), suggesting that restoration plantings had not yet attained maximum biomass carbon. Mean biomass carbon accumulation during the first 34 years after planting was estimated as 4.2 ± 0.6 Mg C ha–1 year–1, with the 10th and 90th quantile regression estimates being 2.1 and 8.8 Mg C ha–1 year–1. There were no significant differences in soil organic carbon (0–30-cm depth) between the plantings, remnant forest and pasture, with all values in the range of 59–67 Mg ha–1. This is in line with other studies showing that soil carbon is slow to respond to changes in land use. Based on our measured rates of biomass carbon accumulation, it would require ~50 years to accumulate the average carbon content of remnant forests. However, it is more realistic to assume the rates will slow with time, and it could take over 100 years to attain a new equilibrium of biomass carbon stocks.
Cold hardening reduces photoinhibition of Eucalypts nitens and E-pauciflora at frost temperatures
Publisher: Springer Science and Business Media LLC
Date: 28-01-1998
Abstract: Photoinhibition of photosynthesis at low temperatures was investigated in two species of subalpine eucalypt, Eucalypts nitens (Deane and Maiden) Maiden and E. pauciflora Sieb. ex Spreng. Imposition of an artificial cold-hardening treatment increased the frost tolerance of leaf tissue and increased tolerance to excess light. Cold-hardened seedlings of both species had a higher photosynthetic capacity than non-hardened seedlings at 6 and 16°C and lower levels of non-photochemical quenching (NPQ) at 20 and 5°C. Furthermore, hardened seedlings had faster rates of NPQ development at 5 and -3.5°C. An increase in minimal fluorescence, which indicates slowly reversible photoinhibition, was evident in all seedlings at -1.5 and -3.5°C but was less pronounced in hardened seedlings, with a threefold faster rate of development of NPQ, at -3.5°C than non-hardened seedlings. Hardened seedlings also recovered faster from photoinhibition at -3.5°C. Thus cold hardening increased tolerance to high light in these species. Differences between E. nitens and E. pauciflora in their response to excess light were small and significant only at -3.5°C. Faster recovery from photoinhibition of E. pauciflora was consistent with its occurrence in colder habitats than E. nitens.
Global change effects on plant communities are magnified by time and the number of global change factors imposed
Publisher: Proceedings of the National Academy of Sciences
Date: 19-08-2019
Abstract: Accurate prediction of community responses to global change drivers (GCDs) is critical given the effects of bio ersity on ecosystem services. There is consensus that human activities are driving species extinctions at the global scale, but debate remains over whether GCDs are systematically altering local communities worldwide. Across 105 experiments that included over 400 experimental manipulations, we found evidence for a lagged response of herbaceous plant communities to GCDs caused by shifts in the identities and relative abundances of species, often without a corresponding difference in species richness. These results provide evidence that community responses are pervasive across a wide variety of GCDs on long-term temporal scales and that these responses increase in strength when multiple GCDs are simultaneously imposed.
Exposure and Nutrients As Delimiters of Lichen Communities in Continental Antarctica
Publisher: Cambridge University Press (CUP)
Date: 11-1995
DOI: 10.1016/S0024-2829(95)80010-7
Abstract: Lichens dominate the terrestrial vegetation of the ice-free regions of continental Antarctica. Vegetation patterns were studied in the Windmill Islands Oasis, Wilkes Land, continental Antarctica, in relation to edaphic features to elucidate the factors that govern lichen distribution and abundance. Vegetation was studied on a low rounded knoll on Clark Peninsula some 3 km North East of the present Casey station. Substratum nutrient levels vary considerably across the knoll due to the presence of an abandoned penguin rookery on the crest and the uneven topography provides both sheltered and exposed sites. Along a 130 m-long transect crossing the knoll from South to North, a total of 25 species of lichen and one moss were identified, the vegetation being dominated by Umbilicaria decussata, Pseudephebe minuscula, Usnea sphacelata and U. antarctica . TWINSPAN analysis of species distributions identified six sociations, the distribution of which were related to substratum structure and chemistry. Several species were restricted to nutrient-rich zones while late-lying snow restricted all species to varying degrees.
Changes in the microbial community structure of bacteria, archaea and fungi in response to elevated CO2 A ustralian native grassland soil
Publisher: Wiley
Date: 08-10-2012
DOI: 10.1111/J.1462-2920.2012.02855.X
Abstract: The microbial community structure of bacteria, archaea and fungi is described in an Australian native grassland soil after more than 5 years exposure to different atmospheric CO2 concentrations ([CO2]) (ambient, +550 ppm) and temperatures (ambient, + 2°C) under different plant functional types (C3 and C4 grasses) and at two soil depths (0-5 cm and 5-10 cm). Archaeal community ersity was influenced by elevated [CO2], while under warming archaeal 16S rRNA gene copy numbers increased for C4 plant Themeda triandra and decreased for the C3 plant community (P < 0.05). Fungal community ersity resulted in three groups based upon elevated [CO2], elevated [CO2] plus warming and ambient [CO2]. Overall bacterial community ersity was influenced primarily by depth. Specific bacterial taxa changed in richness and relative abundance in response to climate change factors when assessed by a high-resolution 16S rRNA microarray (PhyloChip). Operational taxonomic unit signal intensities increased under elevated [CO2] for both Firmicutes and Bacteroidetes, and increased under warming for Actinobacteria and Alphaproteobacteria. For the interaction of elevated [CO2] and warming there were 103 significant operational taxonomic units (P < 0.01) representing 15 phyla and 30 classes. The majority of these operational taxonomic units increased in abundance for elevated [CO2] plus warming plots, while abundance declined in warmed or elevated [CO2] plots. Bacterial abundance (16S rRNA gene copy number) was significantly different for the interaction of elevated [CO2] and depth (P < 0.05) with decreased abundance under elevated [CO2] at 5-10 cm, and for Firmicutes under elevated [CO2] (P < 0.05). Bacteria, archaea and fungi in soil responded differently to elevated [CO2], warming and their interaction. Taxa identified as significantly climate-responsive could show differing trends in the direction of response ('+' or '-') under elevated CO2 or warming, which could then not be used to predict their interactive effects supporting the need to investigate interactive effects for climate change. The approach of focusing on specific taxonomic groups provides greater potential for understanding complex microbial community changes in ecosystems under climate change.
Warming and elevated CO2 affect the relationship between seed mass, germinability and seedling growth in Austrodanthonia caespitosa, a dominant Australian grass
Publisher: Wiley
Date: 26-03-2008
Relative humidity has dramatic impacts on leaf morphology but little effect on stomatal index or density in Nothofagus cunninghamii (Nothofagaceae)
Publisher: CSIRO Publishing
Date: 2012
DOI: 10.1071/BT12110
Abstract: Reconstructing past environmental conditions using proxies based on fossil and subfossil leaves is difficult because leaf form is influenced by many interacting environmental factors such as temperature, CO2 concentration, light, soil water availability and, potentially, atmospheric relative humidity (RH). We used a species important for palaeo-environmental reconstruction, the southern beech, Nothofagus cunninghamii, to test for the effects of a 50% difference in RH on leaf morphology and epidermal anatomy in a glasshouse experiment. Leaf size, shape and thickness were all strongly affected by RH with leaves from high humidity being larger, narrower and thicker than those from low humidity regardless of plant accession. RH impacts on epidermal characters were generally slight and dependent upon accession. In particular, epidermal cell size was remarkably consistent across accessions and RH levels. Thus, gross leaf morphology of N. cunninghamii was sensitive to changes in RH but, on average, epidermal characters were not. Thus, palaeoenvironmental signals from the epidermis of this species are unlikely to be affected by variation in RH, provided sufficient numbers of leaves are investigated. Gross leaf morphology, however, was strongly related to RH and should not be used for palaeo-climatic reconstruction if changes in RH are likely.
Photochemistry, energy dissipation and cold-hardening in Eucalyptus nitens and E. pauciflora
Publisher: CSIRO Publishing
Date: 1998
DOI: 10.1071/PP98027
Abstract: The allocation of absorbed photon energy to thermal energy dissipation and photosynthetic electron transport was investigated as a function of photosynthetic photon flux density (PPFD) and temperature in two species of subalpine eucalypt, Eucalyptus nitens (Deane et Maiden) Maiden and E. pauciflora Sieb. ex Spreng. The proportion of absorbed light utilised in photosynthetic electron transport decreased with increasing PPFD, and the decrease was more pronounced the lower the temperature. The proportion erted into dissipation processes increased with increasing PPFD to a maximum where it reached a plateau. This maximum increased with decreasing temperature. Exposure to a succession of cold (4˚C) nights increased the photochemical quantum yield of photosystem II and decreased the allocation of excitation energy to thermal dissipation processes in conditions of excess light, particularly at low temperatures. Consequently, the photosynthetic electron transport rate (ETR) was higher and heat dissipation rate (HDR) was lower in hardened plants than in non-hardened plants at low temperatures. At 20˚C, ETR was generally higher than HDR in all plants, but as the temperature decreased, HDR became the dominant process. The PPFD at which HDR exceeded ETR decreased with decreasing temperature, and at low temperatures was always lower in non-hardened plants than hardened plants, although quite similar between species.
Plant communities, populations and individuals have distinct responses to short‐term warming and neighbour biomass removal in two montane grasslands
Publisher: Wiley
Date: 2021
DOI: 10.1111/AVSC.12557
Ambient changes exceed treatment effects on plant species abundance in global change experiments
Publisher: Wiley
Date: 18-10-2018
DOI: 10.1111/GCB.14442
Abstract: The responses of species to environmental changes will determine future community composition and ecosystem function. Many syntheses of global change experiments examine the magnitude of treatment effect sizes, but we lack an understanding of how plant responses to treatments compare to ongoing changes in the unmanipulated (ambient or background) system. We used a database of long-term global change studies manipulating CO
Elevated CO2 and warming effects on grassland plant mortality are determined by the timing of rainfall
Publisher: Oxford University Press (OUP)
Date: 28-02-2017
DOI: 10.1093/AOB/MCX006
FIELD PHOTOSYNTHETIC ACTIVITY OF LICHENS IN THE WINDMILL ISLANDS OASIS, WILKES LAND, CONTINENTAL ANTARCTICA
Publisher: Wiley
Date: 03-1994
Cold-induced photoinhibition and foliar pigment dynamics of Eucalyptus nitens seedlings during establishment
Publisher: CSIRO Publishing
Date: 2001
DOI: 10.1071/PP01039
Abstract: The effects of cold-induced photoinhibition on chlorophyll and carotenoid dynamics and xanthophyll cycling in Eucalyptus nitens (Deane and Maiden) Maiden were assessed between planting and 32 weeks after planting. The seedlings were fertilised or nutrient-deprived (non-fertilised) before planting and shaded or not shaded after planting. The experimental site was 700 m a.s.l., which is considered marginal for establishment of E. nitens plantations in Tasmania due to low mean annual minimum temperatures. Low temperature–high light conditions caused a reduction in variable to maximal chlorophyll fluorescence ratio (F v /F m ), which was more pronounced in non-fertilised than in fertilised seedlings. Shadecloth shelters alleviated this depression. Except in shaded fertilised seedlings, F v /F m did not recover to the level before planting until after 20 weeks. Total chlorophyll content was initially reduced in shaded treatments but subsequently increased with increasing temperatures and F v /F m. Total xanthophyll content and xanthophylls per unit chlorophyll remained relatively constant in fertilised seedlings but decreased in non-fertilised seedlings within 2 weeks after planting. Total xanthophyll and xanthophylls per unit chlorophyll subsequently recovered in non-shaded, non-fertilised seedlings with increasing temperatures and F v /F m. Diurnal [yield and non-photochemical quenching (NPQ) and seasonal (F v /F m) variation in chlorophyll fluorescence parameters were not reflected in xanthophyll cycling during the period of most severe photoinhibition. This result may indicate that chlorophyll–xanthophylls protein complexes form in winter-acclimated E. nitens foliage as have been demonstrated to occur in Eucalyptus pauciflora Sieb. ex Spreng. (Gilmore and Ball 2000, Proceedings of the National Academy of Sciences USA 97, 11098–11101).
Generic Carbon Cascade Analysis technique for carbon emission management
Publisher: Elsevier BV
Date: 09-2014
Interactive effects of nitrogen and irradiance on sustained xanthophyll cycle engagement in Eucalyptus nitens leaves during winter
Publisher: Springer Science and Business Media LLC
Date: 2003
DOI: 10.1007/S00442-002-1097-Z
Abstract: Eucalyptus nitens is a species that is adapted to low temperature. This study examines xanthophyll-cycle engagement in E. nitens seedlings exposed to cold-induced photoinhibitory conditions under different levels of irradiance and nutrient status. Xanthophyll-cycle pool size indicated an increased requirement for light energy dissipation under high irradiance and low nutrient status. Greater sensitivity to photoinhibition of non-shaded seedlings indicated that sustained xanthophyll-cycle engagement may occur in response to damaged chlorophyll. Within irradiance treatments, fertilised seedlings had higher photochemical efficiency and faster recovery from photoinhibition than unfertilised seedlings. These results demonstrate that fertilised compared to unfertilised seedlings can utilise a greater proportion of incident light under cold temperature conditions
Warming has a larger and more persistent effect than elevated CO2 on growing season soil nitrogen availability in a species-rich grassland
Publisher: Springer Science and Business Media LLC
Date: 28-10-2017
The impact of introduced ship rats (Rattus rattus) on seedling recruitment and distribution of a subantarctic megaherb (Pleurophyllum hookeri)
Publisher: Wiley
Date: 02-2005
Genotypic differences in growth and stomatal morphology of Southern Beech, Nothofagus cunninghamii, exposed to depleted CO2 concentrations
Publisher: CSIRO Publishing
Date: 2000
DOI: 10.1071/PP99195
Abstract: Nothofagus cunninghamii (Hook.) Oerst. clones of four different genotypes from Mt Field National Park, Tasmania were grown at both current (~370 mol mol–1 ) and depleted (~170 mol mol –1 ) CO2. Growth was significantly less in the lower [CO2] treatment in all genotypes. The amount of growth reduction caused by low [CO2] depended strongly upon genotype and varied from less than 30% to greater than 75% reduction of whole plant biomass when compared to growth at current [CO2]. Specific leaf area was significantly greater in all plants grown in reduced [CO2], whereas in idual leaf area was not significantly affected by [CO2]. The direction and magnitude of the response of stomatal index, stomatal density and epidermal cell density to [CO2] was strongly dependent upon genotype. [CO2] had a significant effect on the length of the stomatal pore, but the magnitude of the effect (~3%) was trivial compared to changes in stomatal density (up to 20%). There was a significant (P 0.01) and positive relationship between the response of stomatal density and growth response of a genotype. Therefore, we propose that the response of stomatal density to [CO2] controls the relative growth response of N. cunninghamii and that this response is highly dependent upon genotype.
Selective grazing modifies previously anticipated responses of plant community composition to elevated CO2 in a temperate grassland
Publisher: Wiley
Date: 11-11-2014
DOI: 10.1111/GCB.12301
Abstract: Our limited understanding of terrestrial ecosystem responses to elevated CO2 is a major constraint on predicting the impacts of climate change. A change in botanical composition has been identified as a key factor in the CO2 response with profound implications for ecosystem services such as plant production and soil carbon storage. In temperate grasslands, there is a strong consensus that elevated CO2 will result in a greater physiological stimulus to growth in legumes and to a lesser extent forbs, compared with C3 grasses, and the presumption this will lead in turn to a greater proportion of these functional groups in the plant community. However, this view is based on data mainly collected in experiments of three or less years in duration and not in experiments where defoliation has been by grazing animals. Grazing is, however, the most common management of grasslands and known in itself to influence botanical composition. In a long-term Free Air Carbon Dioxide Enrichment (FACE) experiment in a temperate grassland managed with grazing animals (sheep), we found the response to elevated CO2 in plant community composition in the first 5 years was consistent with the expectation of increased proportions of legumes and forbs. However, in the longer term, these differences diminished so that the proportions of grasses, legumes and forbs were the same under both ambient and elevated CO2 . Analysis of vegetation before and after each grazing event showed there was a sustained disproportionately greater removal ('apparent selection') of legumes and forbs by the grazing animals. This bias in removal was greater under elevated CO2 than ambient CO2 . This is consistent with sustained faster growth rates of legumes and forbs under elevated CO2 being countered by selective defoliation, and so leading to little difference in community composition.
Special Issue: Ecophysiology of Australasian Plants and Ecosystems.
Publisher: CSIRO Publishing
Date: 2004
DOI: 10.1071/FP04902
Moister soils at elevated CO2 stimulate root biomass but suppress aboveground biomass production in Lolium perenne
Publisher: CSIRO Publishing
Date: 2023
DOI: 10.1071/CP22287
The effects of mechanical disturbance and burn intensity on the floristic composition of two-year old aggregated retention coupes in Tasmanian wet eucalypt forests
Publisher: Elsevier BV
Date: 09-2012
Short-term effects of firebreaks on seedling growth, nutrient concentrations and soil strength in southern Australian wet eucalypt forests
Publisher: Elsevier BV
Date: 08-2012
Co-occurring grass species differ in their associated microbial community composition in a temperate native grassland
Publisher: Springer Science and Business Media LLC
Date: 20-11-2013
The great escape: patterns of enemy release are not explained by time, space or climate
Publisher: The Royal Society
Date: 16-08-2023
Abstract: When a plant is introduced to a new ecosystem it may escape from some of its coevolved herbivores. Reduced herbivore damage, and the ability of introduced plants to allocate resources from defence to growth and reproduction can increase the success of introduced species. This mechanism is known as enemy release and is known to occur in some species and situations, but not in others. Understanding the conditions under which enemy release is most likely to occur is important, as this will help us to identify which species and habitats may be most at risk of invasion. We compared in situ measurements of herbivory on 16 plant species at 12 locations within their native European and introduced Australian ranges to quantify their level of enemy release and understand the relationship between enemy release and time, space and climate. Overall, plants experienced approximately seven times more herbivore damage in their native range than in their introduced range. We found no evidence that enemy release was related to time since introduction, introduced range size, temperature, precipitation, humidity or elevation. From here, we can explore whether traits, such as leaf defences or phylogenetic relatedness to neighbouring plants, are stronger indicators of enemy release across species.
Seasonal not annual rainfall determines grassland biomass response to carbon dioxide
Publisher: Springer Science and Business Media LLC
Date: 28-05-2014
DOI: 10.1038/NATURE13281
Abstract: The rising atmospheric concentration of carbon dioxide (CO2) should stimulate ecosystem productivity, but to what extent is highly uncertain, particularly when combined with changing temperature and precipitation. Ecosystem response to CO2 is complicated by biogeochemical feedbacks but must be understood if carbon storage and associated d ening of climate warming are to be predicted. Feedbacks through the hydrological cycle are particularly important and the physiology is well known elevated CO2 reduces stomatal conductance and increases plant water use efficiency (the amount of water required to produce a unit of plant dry matter). The CO2 response should consequently be strongest when water is limiting although this has been shown in some experiments, it is absent from many. Here we show that large annual variation in the stimulation of above-ground biomass by elevated CO2 in a mixed C3/C4 temperate grassland can be predicted accurately using seasonal rainfall totals summer rainfall had a positive effect but autumn and spring rainfall had negative effects on the CO2 response. Thus, the elevated CO2 effect mainly depended upon the balance between summer and autumn/spring rainfall. This is partly because high rainfall during cool, moist seasons leads to nitrogen limitation, reducing or even preventing biomass stimulation by elevated CO2. Importantly, the prediction held whether plots were warmed by 2 °C or left unwarmed, and was similar for C3 plants and total biomass, allowing us to make a powerful generalization about ecosystem responses to elevated CO2. This new insight is particularly valuable because climate projections predict large changes in the timing of rainfall, even where annual totals remain static. Our findings will help resolve apparent differences in the outcomes of CO2 experiments and improve the formulation and interpretation of models that are insensitive to differences in the seasonal effects of rainfall on the CO2 response.
Strategies of light energy utilisation, dissipation and attenuation in six co-occurring alpine heath species in Tasmania
Publisher: CSIRO Publishing
Date: 2003
DOI: 10.1071/FP03145
Abstract: Alpine environments are characterised by low temperatures and high light intensities. This combination leads to high light stress owing to the imbalance between light energy harvesting and its use in photochemistry. In extreme cases, high light stress can lead to the level of photo-oxidative damage exceeding the rate of repair to the photosynthetic apparatus. Plant species may vary in the mechanisms they use to prevent photodamage, but most comparisons are of geographically and ecologically distinct species. Differences in leaf colouration suggested that photoprotective strategies might differ among Tasmanian evergreen alpine shrub species. We compared chlorophyll fluorescence and leaf pigment composition in six co-occurring alpine shrub species on the summit of Mt Wellington, southern Tasmania, Australia, during spring and autumn. We found marked differences among species in light energy utilisation, attenuation and dissipation. Ozothamnus ledifolius maintained a large capacity for photosynthetic light utilisation and thus, had a low requirement for light dissipation. All five of the other species relied on xanthophyll-cycle-dependent thermal energy dissipation. In addition Epacris serpyllifolia, Richea sprengelioides and Leptospermum rupestre had foliar anthocyanins that would attenuate photosynthetically active light in the leaf. During spring, all species retained de-epoxidised xanthophylls through the night and the pre-dawn concentration of antheraxanthin and zeaxanthin was significantly correlated with reductions in pre-dawn Fv / Fm. We propose that these species use three photoprotective strategies to cope with the combination of high light and low temperature.
Effects of a rapid, unseasonal rewetting event on mineral location in Antarctic lichens
Publisher: Wiley
Date: 10-1997
DOI: 10.1046/J.1469-8137.1997.00785.X
Abstract: During the middle of the 1992 austral winter in the northern Windmill Islands, continental Antarctica, a highly unusual climatic event occurred in which the air temperature exceeded 0°C for some 60 h, at the end of which there was a significant rain shower before the ambient temperature returned to subzero conditions. This event caused most of the snow cover to melt and refreeze as clear ice. Lichens were thus rehydrated in the dark, in some places completely inundated, then frozen in ice. The effect that these conditions had on the distribution of K, Na, Mg and Ca within the thallus was estimated for two of the dominant macrolichen species, Umbilicaria decussata (Vill.) Zahlbr. and Usnea sphacelata R.Br, from three sites on a knoll on Clark Peninsula. One site acted as a natural control, owing to the very deep snow cover at the site, which protected lichens from the rewetting event. Despite persistent differences between species and the various sites, there was no overall effect of the climatic event on the membrane integrity of either lichen species. Only Usnea sphacelata from the most exposed site showed a significant leakage of K across the cell membrane, which indicated a loss of membrane integrity. Overall, both species were tolerant of the extreme conditions, although Umbilicaria decussata was the more tolerant.
Variable-retention harvesting in Tasmania: regeneration success?
Publisher: Informa UK Limited
Date: 16-09-2015
Simple additive effects are rare: a quantitative review of plant biomass and soil process responses to combined manipulations of CO2
Publisher: Wiley
Date: 27-06-2012
DOI: 10.1111/J.1365-2486.2012.02745.X
Abstract: In recent years, increased awareness of the potential interactions between rising atmospheric CO2 concentrations ([ CO2 ]) and temperature has illustrated the importance of multifactorial ecosystem manipulation experiments for validating Earth System models. To address the urgent need for increased understanding of responses in multifactorial experiments, this article synthesizes how ecosystem productivity and soil processes respond to combined warming and [ CO2 ] manipulation, and compares it with those obtained in single factor [ CO2 ] and temperature manipulation experiments. Across all combined elevated [ CO2 ] and warming experiments, biomass production and soil respiration were typically enhanced. Responses to the combined treatment were more similar to those in the [ CO2 ]-only treatment than to those in the warming-only treatment. In contrast to warming-only experiments, both the combined and the [ CO2 ]-only treatments elicited larger stimulation of fine root biomass than of aboveground biomass, consistently stimulated soil respiration, and decreased foliar nitrogen (N) concentration. Nonetheless, mineral N availability declined less in the combined treatment than in the [ CO2 ]-only treatment, possibly due to the warming-induced acceleration of decomposition, implying that progressive nitrogen limitation (PNL) may not occur as commonly as anticipated from single factor [ CO2 ] treatment studies. Responses of total plant biomass, especially of aboveground biomass, revealed antagonistic interactions between elevated [ CO2 ] and warming, i.e. the response to the combined treatment was usually less-than-additive. This implies that productivity projections might be overestimated when models are parameterized based on single factor responses. Our results highlight the need for more (and especially more long-term) multifactor manipulation experiments. Because single factor CO2 responses often dominated over warming responses in the combined treatments, our results also suggest that projected responses to future global warming in Earth System models should not be parameterized using single factor warming experiments.
HORIZONTAL STRUCTURES ON PNEUMATOPHORES OF AVICENNIA-MARINA (FORSK) VIERH - A NEW SITE OF OXYGEN CONDUCTANCE
Publisher: Oxford University Press (OUP)
Date: 04-1994
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