Erik Veneklaas

Thermal imagery of woodland tree canopies provides new insights into drought-induced tree mortality

Publisher: Elsevier BV

Date: 08-2022

DOI: 10.1016/J.SCITOTENV.2022.155395

Abstract: Our understanding of how water dynamics determines the probability of tree mortality during drought is incomplete. Here we help address this shortcoming by coupling approaches from the disciplines of ecophysiology, geophysics and remote sensing in a woodland ecosystem undergoing protracted drying. Water uptake and use strategies varied between the dominant canopy species of the ecosystem. At one extreme were species that tightly regulate their water status, which is broadly consistent with the definition of isohydry. The higher leaf temperatures revealed by thermal imagery of these isohydric species are likely a reflection of reduced latent cooling owing to a stringent control of transpiration rate. Where silty sediments occur in the root zone, this strategy may have the effect of limiting the water sources available to these species during prolonged drought because of an insufficient hydraulic gradient for water uptake. In contrast were species that allowed their water status to fluctuate, operating in a fashion more consistent with anisohydry. For these species, latent cooling owing to relatively high transpiration rates maintained leaf temperatures near, or below, the ambient air temperature. The resulting drawdown in leaf water potential between soil and leaves in these anisohydric species may generate a sufficient hydraulic gradient to enable water uptake from silty soil during seasonal or prolonged droughts. In this way the spatial distribution of fine textured soil could indicate areas where the isohydric hydraulic control strategy is disadvantageous during prolonged droughts or where annual soil water recharge has fallen below a critical threshold.

Tree host-pathogen interactions as influenced by drought timing

Publisher: Oxford University Press (OUP)

Date: 09-10-2018

DOI: 10.1093/TREEPHYS/TPY113

Abstract: There is increasing concern about tree mortality around the world due to climatic extremes and associated shifts in pest and pathogen dynamics. Yet, empirical studies addressing the interactive effect of biotic and abiotic stress on plants are very rare. Therefore, in this study, we examined the interaction between drought stress and a canker pathogen, Quambalaria coyrecup, on the eucalypt - Corymbia calophylla (marri), which is experiencing increasing drought stress. We hypothesized that drought stress would increase marri's susceptibility to canker disease, and cankers would have the largest negative effect on plants that are already drought stressed before pathogen inoculation. To test the hypotheses, in a glasshouse, marri saplings were exposed to drought either before or after pathogen inoculation, or were well-watered or droughted throughout the experiment either with or without inoculation. Canker development was greater in well-watered saplings than in droughted saplings, with the fastest development occurring in well-watered saplings that had experienced drought stress before inoculation. Irrespective of water treatments, marri saplings employed phenol-based localized biochemical defence against the pathogen. Drought reduced photosynthesis and growth, however, a negative effect of canker disease on saplings' physiological performance was only observed in well-watered saplings. In well-watered saplings, canker-induced loss of sapwood function contributed to reduced whole-plant hydraulic conductance, photosynthesis and growth. The results provide evidence that timing of drought stress influences host physiology, and host condition influences canker disease susceptibility through differences in induced biochemical defence mechanisms. The observations highlight the importance of explicitly incorporating abiotic and biotic stress, as well as their interactions, in future studies of tree mortality in drought-prone regions worldwide.

Putting provenance into perspective: the relative importance of restoration site conditions over seed sourcing

Publisher: Wiley

Date: 08-08-2023

DOI: 10.1111/REC.13989

Abstract: Post‐mining scenarios present challenges for restoration in a wide range of environments, especially in the context of climate change. The source of seed for restoration has been an issue of intense focus, as seed provenance can impact plant fitness and restoration outcomes. However, post‐mining landscapes require substrate reconstruction prior to vegetation re‐establishment. Critically, the relative importance of provenance and substrate in ecosystem recovery has been rarely quantified in a statistically rigorous framework. We established a large provenance trial with Banksia attenuata and Eucalyptus todtiana at two Western Australian mine sites in post‐mining reconstructed and adjoining un‐mined substrates. We show that site and substrate were 4 and 26 times more important than provenance in explaining survival for B. attenuata and E. todtiana , respectively. At one site, there was 100% mortality in the post‐mining substrate but high survival and no clear provenance effect in the un‐mined substrate. At the second site, there was again no clear provenance effect, but E. todtiana survival was higher in the post‐mining than un‐mined substrate. Our results show that post‐mining substrate changes can overwhelm provenance issues. Consequently, where substrates are highly impacted, alternative restoration targets and/or greater investment in substrate research are needed to improve restoration outcomes. Due to the thousands of mines across the world, this is an internationally relevant finding with important implications for investment into global ecosystem recovery.

Functional traits of riparian trees in the lower Fitzroy River, Western Australia

Publisher: Wiley

Date: 17-10-2022

DOI: 10.1002/ECO.2488

Abstract: Riparian trees are critically important for maintaining the ecological function of freshwater ecosystems. Globally, anthropogenic changes to water regimes are impacting the health and distribution of riparian trees. Understanding the physiological constraints on the distribution of riparian tree species in relation to the water regime is essential for informed water resource management that seeks to limit impacts on riparian trees. To fill an identified knowledge gap for the Fitzroy River, a significant river in the wet–dry tropics of north‐western Australia, we used a trait‐based approach to characterise nine common riparian tree species in relation to their distribution along a hydrological gradient. We assessed key functional traits related to drought and flood flows. Leaf mass per unit area (LMA), leaf dry matter content (LDMC), foliar carbon content (% C) and the ratio of carbon to nitrogen (C:N) are broadly related to plant productivity and durability and may reflect resistance to fluvial stress. Traits related to water availability were stem specific density (SSD), mean xylem vessel diameter and xylem vessel density, as well as foliar δ 13 C which is related to water use efficiency, and leaf osmotic potential at full hydration ( π 100 ) as a measure of drought tolerance. We found that π 100 , δ 13 C and SSD values reflected species hydrological habitat preferences, with higher δ 13 C values and lower π 100 for species distributed in the drier floodplain habitats, compared with species constrained to the riverbank. Low SSD values for species close to the riverbank may be indicative of aerenchyma tissue in response to flooding. Differences in leaf trait values were primarily attributed to differences between evergreen Myrtaceous and deciduous non‐Myrtaceous species, rather than hydrological habitat preferences. LMA was greatest for the Myrtaceous study species, with deciduous non‐Myrtaceous species associated with wetter habitats having the lowest values. The physiology of riparian trees in northern Australia is not well described for the majority of species. Our study provides insight into plant functional strategies in response to both flooding and drought and is a critical step in understanding plant responses to future water‐take scenarios to support evidence‐based decision making.

Investigating above- vs. below-ground competition by accounting for azimuth of competitors in native eucalypt forests

Publisher: Elsevier BV

Date: 08-2023

DOI: 10.1016/J.FORECO.2023.121103

AusTraits, a curated plant trait database for the Australian flora

Publisher: Springer Science and Business Media LLC

Date: 30-09-2021

DOI: 10.1038/S41597-021-01006-6

Abstract: We introduce the AusTraits database - a compilation of values of plant traits for taxa in the Australian flora (hereafter AusTraits). AusTraits synthesises data on 448 traits across 28,640 taxa from field c aigns, published literature, taxonomic monographs, and in idual taxon descriptions. Traits vary in scope from physiological measures of performance (e.g. photosynthetic gas exchange, water-use efficiency) to morphological attributes (e.g. leaf area, seed mass, plant height) which link to aspects of ecological variation. AusTraits contains curated and harmonised in idual- and species-level measurements coupled to, where available, contextual information on site properties and experimental conditions. This article provides information on version 3.0.2 of AusTraits which contains data for 997,808 trait-by-taxon combinations. We envision AusTraits as an ongoing collaborative initiative for easily archiving and sharing trait data, which also provides a template for other national or regional initiatives globally to fill persistent gaps in trait knowledge.

Root length is proxy for high-Throughput screening of waterlogging tolerance in Urochloa spp. grasses

Publisher: CSIRO Publishing

Date: 2021

DOI: 10.1071/FP20200

Abstract: C4 perennial Urochloa spp. grasses are widely planted in extensive areas in the tropics. These areas are continuously facing waterlogging events, which limits plant growth and production. However, no commercial cultivar combining excellent waterlogging tolerance with superior biomass production and nutritional quality is available. The objective of this study was to identify root traits that can be used for selecting waterlogging tolerant species of Urochloa. Root respiration, root morphological, architectural and anatomical traits were evaluated in eight contrasting Urochloa spp. genotypes grown under aerated or deoxygenated stagnant solutions. Moreover, modelling of internal aeration was used to relate differences in root traits and root growth in waterlogged soils. Increased aerenchyma formation in roots, reduced stele area and development of a fully suberised exodermis are characteristics improving internal aeration of roots and therefore determining waterlogging tolerance in these C4 forage grasses. Waterlogging-tolerant genotypes had steeper root angles and greater root lengths than the waterlogging-sensitive genotypes. In stagnant conditions, waterlogging-tolerant genotypes had a greater proportion of aerenchyma and reduced stele area in root cross-sections, had deeper roots, steeper root angle and larger root biomass, which in turn, allowed for greater shoot biomass. Total root length had the strongest positive influence on shoot dry mass and can therefore be used as proxy for selecting waterlogging tolerant Urochloa genotypes.

Microbial inoculation to improve plant performance in mine-waste substrates

Publisher: Wiley

Date: 04-01-2022

DOI: 10.1002/LDR.4165

Abstract: Mining activities alter soil physicochemical and biological properties that are critical for plant establishment. Revitalisation of soil biological properties via microbial inoculations can potentially be adopted to improve vegetation restoration. Here, we evaluate the feasibility of using beneficial microorganisms in the form of commercially available inoculants to enhance plant performance in a non‐toxic and infertile mine‐waste substrate, using pigeon pea [ Cajanus cajan (L) Millsp.] as a test plant. Six treatments were established to investigate the effects of inoculants ( Bradyrhizobium spp., microbial mix and uninoculated controls) and water availability (low and moderate) in a factorial design over 6 months. Plant performance was determined by physiological parameters (leaf gas exchange, leaf carbon, nitrogen and stable isotopes) and growth (height and biomass). Plant xylem sap phytohormones were measured to determine the plants' physiological status and effects of inoculation treatments. Results revealed that water had a greater effect on plant growth than inoculation treatments. Inoculation treatments, however, improved some physiological parameters. This study suggests that physical conditions such as soil moisture and nutrient availability may occlude more subtle (direct or interactive) effects of beneficial soil microbes on plant growth and plant condition. Prior knowledge on the biological and physicochemical properties of the soil to be amended, and on plant species‐specific responses, would be needed to customise microbial inoculants for maximum benefits to ecological restoration, to support future adoption of this practice.

No evidence of regulation in root-mediated iron reduction in two Strategy I cluster-rooted Banksia species (Proteaceae)

Publisher: Springer Science and Business Media LLC

Date: 27-01-2021

DOI: 10.1007/S11104-021-04849-5

Apparent Overinvestment in Leaf Venation Relaxes Leaf Morphological Constraints on Photosynthesis in Arid Habitats

Publisher: Oxford University Press (OUP)

Date: 26-10-2016

DOI: 10.1104/PP.16.01313

Coccidiosis in green turtles (Chelonia mydas) in Australia: Pathogenesis, spatial and temporal distribution, and climate-related determinants of disease outbreaks

Publisher: Wildlife Disease Association

Date: 31-03-2020

DOI: 10.7589/2019-05-115

Abstract: An epizootic of coccidiosis in free-ranging green turtles (

Stockpiling disrupts the biological integrity of topsoil for ecological restoration

Publisher: Springer Science and Business Media LLC

Date: 02-12-2021

DOI: 10.1007/S11104-021-05217-Z

Abstract: Biotic and abiotic properties of soils can hinder or facilitate ecological restoration, and management practices that impact edaphic factors can strongly influence plant growth and restoration outcomes. Salvaged topsoil is an invaluable resource for mine-site restoration, and a common practice is topsoil transfer from mined areas to restoration sites. However, direct transfer is often not feasible, necessitating storage in stockpiles. We evaluated the effects of topsoil stockpiling on plant performance across erse ecosystems impacted by mining throughout Western Australia. We conducted a bioassay experiment using a widespread native Acacia species to assess how topsoil storage might impact plant growth, physiology, and nodulation by N-fixing bacteria using soils from native reference vegetation and stockpiled soils from six mine sites across Western Australia. Plant responses varied across mine sites, but overall plants performed better in soils collected from native vegetation, exhibiting greater biomass, more root nodules, and higher water-use efficiency compared to those grown in stockpiled soils. Soil physiochemistry showed few and minor differences between native soils and stockpiles. Results strongly suggest observed differences in plant performance were biotic in nature. This study highlights the negative effects of topsoil storage on the biological integrity of soil across erse ecosystems, with important implications for mine-site restoration our results show that topsoil management can strongly influence plant performance, and stockpiled soils are likely inferior to recently disturbed topsoil for restoration purposes. We also use this study to illustrate the utility of bioassays for assessing soil quality for ecological restoration.

Investigating the effect of neighbour competition on individual tree growth in thinned and unthinned eucalypt forests

Publisher: Elsevier BV

Date: 12-2021

DOI: 10.1016/J.FORECO.2021.119637

Patterns and drivers of structure, diversity, and composition in species‐rich shrublands restored after mining

Publisher: Wiley

Date: 21-04-2021

DOI: 10.1111/REC.13360

Abstract: Long‐term studies of vegetation recovery following post‐mining restoration in low‐productivity, high‐stress areas are limited, but essential for understanding underlying ecological processes and evaluating management practices. This study's goal was to describe temporal patterns of recovery (up to 37 years) in vegetation structure, floristic ersity, and composition following post‐mining restoration at two sites, and identify potential drivers of restoration outcomes, in the nutrient‐poor, seasonally dry, species‐rich, fire‐prone kwongan vegetation of southwest Western Australia. Vegetation development is progressing and restoration measures are within range of native reference values, but there is large variation in both patterns observed and restoration outcomes. Several patterns described share similarities with post‐fire recovery of kwongan, and post‐disturbance recovery of other low‐productivity, high‐stress, fire‐prone systems. However, differences in some patterns between sites indicate differences in the underlying mechanisms of recovery. Many management and environmental variables emerge as significant drivers of restoration outcomes but age, fire, and the planting of seedlings account for the largest amount of variation. Adaptive management at both sites appears to be facilitating improved restoration outcomes over time. Using a combination of space‐for‐time, plot level, and linear mixed effects modeling perspectives to examine patterns provides greater insights into restoration recovery than a chronosequence perspective alone. This study will inform restoration practices and outcomes not only in kwongan but in other comparable systems also.

Flow similarity, stochastic branching, and quarter-power scaling in plants

Publisher: Oxford University Press (OUP)

Date: 28-07-2022

DOI: 10.1093/PLPHYS/KIAC358

Abstract: The origin of allometric scaling patterns that are multiples of one-fourth has long fascinated biologists. While not universal, quarter-power scaling relationships are common and have been described in all major clades. Several models have been advanced to explain the origin of such patterns, but questions regarding the discordance between model predictions and empirical data have limited their widespread acceptance. Notable among these is a fractal branching model that predicts power-law scaling of both metabolism and physical dimensions. While a power law is a useful first approximation to some data sets, nonlinear data compilations suggest the possibility of alternative mechanisms. Here, we show that quarter-power scaling can be derived using only the preservation of volume flow rate and velocity as model constraints. Applying our model to land plants, we show that incorporating biomechanical principles and allowing different parts of plant branching networks to be optimized to serve different functions predicts nonlinearity in allometric relationships and helps explain why interspecific scaling exponents covary along a fractal continuum. We also demonstrate that while branching may be a stochastic process, due to the conservation of volume, data may still be consistent with the expectations for a fractal network when one examines sub-trees within a tree. Data from numerous sources at the level of plant shoots, stems, and petioles show strong agreement with our model predictions. This theoretical framework provides an easily testable alternative to current general models of plant metabolic allometry.

High rock content enhances plant resistance to drought in saline topsoils

Publisher: Elsevier BV

Date: 10-2021

DOI: 10.1016/J.JARIDENV.2021.104589

Trait-based formal definition of plant functional types and functional communities in the multi-species and multi-traits context

Publisher: Elsevier BV

Date: 12-2019

DOI: 10.1016/J.ECOCOM.2019.100787

Variation in morphological and physiological root traits and organic acid exudation of three sweet potato (Ipomoea batatas) cultivars under seven phosphorus levels

Publisher: Elsevier BV

Date: 10-2019

DOI: 10.1016/J.SCIENTA.2019.108572

Effect of thinning on growth and allometry of Eucalyptus diversicolor

Publisher: National Inquiry Services Center (NISC)

Date: 20-12-2022

DOI: 10.2989/20702620.2022.2155090

How does spatial micro‐environmental heterogeneity influence seedling recruitment in ironstone outcrops?

Publisher: Wiley

Date: 03-2021

DOI: 10.1111/JVS.13010

Root-zone hypoxia reduces growth of the tropical forage grass Urochloa humidicola in high-nutrient but not low-nutrient conditions

Publisher: Oxford University Press (OUP)

Date: 06-2019

DOI: 10.1093/AOB/MCZ071

Abstract: The perennial C4 grass Urochloa humidicola is widely planted on infertile acidic and waterlogging-prone soils of tropical America. Waterlogging results in soil anoxia, and O2 deficiency can reduce nutrient uptake by roots. Interestingly, both nutrient deficiencies and soil waterlogging can enhance root cortical cell senescence, and the increased gas-filled porosity facilitates internal aeration of roots. We tested the influence of nutrient supply and root-zone O2 on root traits, leaf nutrient concentrations and growth of U. humidicola. Plants were grown in pots in a completely randomized design under aerated or stagnant deoxygenated hydroponic conditions and six nutrient regimes, with low to high concentrations of all essential elements, for 28 d in a controlled-temperature greenhouse. The standard acid solution (SAS) used was previously designed based on infertile acidic soils of the tropical America savannas, and step increases in the concentration of SAS were used in aerated or deoxygenated 0.1 % agar solution, which mimics changes in gas composition in waterlogged soils. Measurements included shoot and root growth, root porosity, root anatomy, radial O2 loss, and leaf tissue nutrient concentrations. Shoot dry mass was reduced for plants in stagnant compared with aerated conditions at high, but not at low, levels of mineral nutrition. In low-nutrition stagnant solution, roots were shorter, of greater porosity and had smaller radial thickness of the stele. Suberized lamellae and lignified sclerenchyma, as well as a strong barrier to radial O2 loss, were documented for roots from all treatments. Leaf nutrient concentrations of K, Mg and Ca (but not N, P and S) were higher in aerated than in stagnant conditions. Under low-nutrient conditions, plant growth in stagnant solution was equal to that in aerated solution, whereas under higher-nutrient regimes growth increased but dry mass in stagnant solution was less than in aerated solution. Slow growth in low-nutrient conditions limited any further response to the low O2 treatment, and greater porosity and smaller stele size in roots would enhance internal O2 movement within roots in the nutrient-limited stagnant conditions. A constitutive barrier to radial O2 loss and aerenchyma facilitates O2 movement to the tips of roots, which presumably contributes to maintaining nutrient uptake and the tolerance of U. humidicola to low O2 in the root-zone.

Composition and ecological drivers of the kwongan scrub and woodlands in the northern Swan Coastal Plain, Western Australia

Publisher: Wiley

Date: 07-04-2019

DOI: 10.1111/AEC.12759

The potential for phosphorus benefits through root placement in the rhizosphere of phosphorus-mobilising neighbours

Publisher: Springer Science and Business Media LLC

Date: 08-2020

DOI: 10.1007/S00442-020-04733-6

Native plant diversity is a stronger driver for soil quality than inorganic amendments in semi-arid post-mining rehabilitation

Publisher: Elsevier BV

Date: 07-2021

DOI: 10.1016/J.GEODERMA.2021.115001

Dihydroxyacetone in the Floral Nectar of Ericomyrtus serpyllifolia (Turcz.) Rye (Myrtaceae) and Verticordia chrysantha Endl. (Myrtaceae) Demonstrates That This Precursor to Bioactive Honey Is Not Restricted to the Genus Leptospermum (Myrtaceae)

Publisher: American Chemical Society (ACS)

Date: 16-05-2023

DOI: 10.1021/ACS.JAFC.3C00673

Leaf manganese concentrations as a tool to assess belowground plant functioning in phosphorus-impoverished environments

Publisher: Springer Science and Business Media LLC

Date: 09-09-2020

DOI: 10.1007/S11104-020-04690-2

Positive heterospecific interactions can increase long‐term diversity of plant communities more than negative conspecific interactions alone

Publisher: Wiley

Date: 10-11-2021

DOI: 10.1111/1365-2435.13941

Abstract: Negative conspecific interactions have been shown to promote ersity in plant communities, as have some heterospecific interactions such as intransitive competition and facilitation. However, it is unclear whether combinations of conspecific and other heterospecific interactions can also promote ersity in plant communities. We therefore investigated the effects of heterospecific plant interaction network architecture with and without conspecific interactions on alpha ersity, beta ersity and long‐term ersity. We simulated long‐term plant community dynamics for theoretical plant interaction scenarios with modular, ring and nested networks of positive or negative heterospecific interactions and conspecific interactions, using a spatially explicit cellular automaton model that accounted for stochastic effects. Throughout the simulations several measures of ersity were recorded. The way that heterospecific interactions affected ersity depended strongly on various characteristics of the architecture of the interaction network. Negative conspecific interactions generally promoted alpha ersity and reduced beta ersity, with a few key exceptions. Positive heterospecific ring interactions that resulted in cyclic appearance and disappearance of species groups led to the greatest long‐term ersity (a measure of the total ersity over time). This study provides new theoretical insights into how the network architecture of heterospecific plant interactions can affect the ersity of plant communities over time and provides the first evidence that heterospecific plant interactions can increase long‐term ersity more than negative conspecific interactions alone. A free Plain Language Summary can be found within the Supporting Information of this article.

Community patterns and environmental drivers in hyper‐diverse kwongan scrub vegetation of Western Australia

Publisher: Wiley

Date: 10-2018

DOI: 10.1111/AVSC.12399

Root positioning and trait shifts in Hibbertia racemosa as dependent on its neighbour's nutrient‐acquisition strategy

Publisher: Wiley

Date: 13-01-2021

DOI: 10.1111/PCE.13991

Water availability drives the effectiveness of inorganic amendments to increase plant growth and substrate quality

Publisher: Elsevier BV

Date: 11-2019

DOI: 10.1016/J.CATENA.2019.104116

Two sides to every leaf: water and CO2 transport in hypostomatous and amphistomatous leaves

Publisher: Wiley

Date: 28-01-2019

DOI: 10.1111/NPH.15652

Abstract: Leaves with stomata on both upper and lower surfaces, termed histomatous, are relatively rare compared with hypostomatous leaves with stomata only on the lower surface. Amphistomaty occurs predominantly in fast-growing herbaceous annuals and in slow-growing perennial shrubs and trees. In this paper, we present the current understanding and hypotheses on the costs and benefits of histomaty related to water and CO

Sugar and dihydroxyacetone ratios in floral nectar suggest continuous exudation and reabsorption in Leptospermum polygalifolium Salisb

Publisher: Elsevier BV

Date: 10-2022

DOI: 10.1016/J.PLANTSCI.2022.111378

Abstract: Leptospermum polygalifolium Salisb. can accumulate high concentrations of dihydroxyacetone (DHA), precursor of the antimicrobial compound methylglyoxal found in honey obtained from floral nectar of Leptospermum spp. Floral nectar dynamics over flower lifespan depends on internal and external factors that invariably impact nectar quality. Current models to estimate nectar quality in Leptospermum spp. overlook time of day, daily (24 h), and long-term dynamics of nectar exudation and accumulation over flower lifespan. To explain the dynamics of nectar quality over flower lifespan, accumulated nectar from flowers of different ages was collected from two L. polygalifolium clones, and then re-collected 24 h later from the same flowers. High-Performance Liquid Chromatography was used to quantify DHA amount and total equivalents of glucose + fructose (Tsugar) per flower in the nectar. DHA and Tsugar amount per flower differed with flower age and between clones. In accumulated nectar, the amount of DHA and Tsugar per flower rose to a broad peak post-anthesis before decreasing. Immediately after peaking DHA declined more quickly than Tsugar in accumulated nectar due to a greater decrease in the exudation of DHA than for Tsugar. The DHA : Tsugar ratios in accumulated nectar and in nectar exuded over the next 24 h were similar and decreased with flower age, indicating that exudation and reabsorption occurred concomitantly across flower development. Hence there is a balance between exudation and reabsorption. A quantitative model suggested that flowers have the potential to exude more DHA and Tsugar than actually accumulated.

Relative growth rate and biomass allocation in 20 Aegilops (Poaceae) species

Publisher: Wiley

Date: 11-1998

DOI: 10.1046/J.1469-8137.1998.00286.X

Shallow soils negatively affect water relations and photosynthesis in two semi-arid Eucalyptus species

Publisher: Elsevier BV

Date: 11-2018

DOI: 10.1016/J.ENVEXPBOT.2018.06.037

TRY plant trait database – enhanced coverage and open access

Publisher: Wiley

Date: 31-12-2019

DOI: 10.1111/GCB.14904

Abstract: Plant traits—the morphological, anatomical, physiological, biochemical and phenological characteristics of plants—determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to bio ersity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait‐based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits—almost complete coverage for ‘plant growth form’. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait–environmental relationships. These traits have to be measured on in idual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives.

Phosphate fertiliser alters carboxylates and bacterial communities in sweet potato (Ipomoea batatas (L.) Lam.) rhizosheaths

Publisher: Springer Science and Business Media LLC

Date: 08-2020

DOI: 10.1007/S11104-020-04646-6

Restoration ecophysiology

Publisher: Wiley

Date: 28-10-2022

DOI: 10.1111/REC.13571

Abstract: As human activities destroy and degrade the world's ecosystems at unprecedented scales, there is a growing need for evidence‐based methods for ecological restoration if we are to preserve bio ersity and ecosystem services. Mining represents one of the most severe anthropogenic disturbances, often necessitating intensive intervention to restore the most basic attributes of native ecosystems. Despite ex les of successful mine‐site restoration, re‐establishing native vegetation in these degraded landscapes remains a significant challenge. Plant ecophysiology—the study of the interactions between plants and the environment—can provide a useful framework for evaluating and guiding mine‐site restoration. By understanding the physiological mechanisms that allow plants to establish and persist in these highly disturbed environments, practitioners may be able to improve restoration outcomes. Specifically, methods in plant ecophysiology can inform site preparation and the selection of plant material for restoration projects, aid in monitoring restoration progress by providing additional insight into plant performance, and ultimately improve our ability to predict restoration trajectories. Here, we review the challenges and benefits of integrating an ecophysiological perspective to mine‐site restoration in Western Australia, a global hotspot of bio ersity and mining operations. Using case studies and ex les from the region's erse ecosystems, we illustrate how an ecophysiological approach can guide the restoration of some of the world's most severely disturbed landscapes. With careful selection of study species and traits and consideration of the specific environmental conditions and stressors within a site, the restoration ecophysiology framework outlined here has the potential to inform restoration strategies across ecosystems.

The barrier to radial oxygen loss impedes the apoplastic entry of iron into the roots of Urochloa humidicola

Publisher: Oxford University Press (OUP)

Date: 05-02-2021

DOI: 10.1093/JXB/ERAB043

Abstract: Lack of O2 and high concentrations of iron (Fe) and manganese (Mn) commonly occur in waterlogged soils. The development of a barrier to impede radial O2 loss (ROL) is a key trait improving internal O2 transport and waterlogging tolerance in plants. We evaluated the ability of the barrier to ROL to impede the entry of excess Fe into the roots of the waterlogging-tolerant grass Urochloa humidicola. Plants were grown in aerated or stagnant deoxygenated nutrient solution with 5 µM or 900 µM Fe. Quantitative X-ray microanalysis was used to determine cell-specific Fe concentrations at two positions behind the root apex in relation to ROL and the formation of apoplastic barriers. At a mature zone of the root, Fe was ‘excluded’ at the exodermis where a suberized lamella was evident, a feature also associated with a strong barrier to ROL. In contrast, the potassium (K) concentration was similar in all root cells, indicating that K uptake was not affected by apoplastic barriers. The hypothesis that the formation of a tight barrier to ROL impedes the apoplastic entry of toxic concentrations of Fe into the mature zones of roots was supported by the significantly higher accumulation of Fe on the outer side of the exodermis.

A threatened ecological community

Publisher: CSIRO Publishing

Date: 2021

DOI: 10.1071/BT20089

Abstract: The rapid expansion of urban areas worldwide is leading to native habitat loss and ecosystem fragmentation and degradation. Although the study of urbanisation’s impact on bio ersity is gaining increasing interest globally, there is still a disconnect between research recommendations and urbanisation strategies. Expansion of the Perth metropolitan area on the Swan Coastal Plain in south-western Australia, one of the world’s thirty-six bio ersity hotspots, continues to affect the Banksia Woodlands (BWs) ecosystem, a federally listed Threatened Ecological Community (TEC). Here, we utilise the framework of a 1989 review of the state of knowledge of BWs ecology and conservation to examine scientific advances made in understanding the composition, processes and functions of BWs and BWs’ species over the last 30 years. We highlight key advances in our understanding of the ecological function and role of mechanisms in BWs that are critical to the management of this ecosystem. The most encouraging change since 1989 is the integration of research between historically disparate ecological disciplines. We outline remaining ecological knowledge gaps and identify key research priorities to improve conservation efforts for this TEC. We promote a holistic consideration of BWs with our review providing a comprehensive document that researchers, planners and managers may reference. To effectively conserve ecosystems threatened by urban expansion, a range of stakeholders must be involved in the development and implementation of best practices to conserve and maintain both bio ersity and human wellbeing.

Climatic origin of provenances of Corymbia calophylla affects canker disease susceptibility, caused by Quambalaria coyrecup, and interactions with drought stress

Publisher: Wiley

Date: 25-10-2022

DOI: 10.1111/EFP.12780

Abstract: Many forest ecosystems are in decline around the world due to increasing biotic and abiotic stresses. Marri ( Corymbia calophylla ) is an endemic and common eucalypt species of southwestern Australia, which is in decline primarily due to stem canker caused by the pathogenic fungus Quambalaria coyrecup . This study determined to what extent disease susceptibility and plant growth were associated with climate at origin for eight provenances of marri. Plants of all provenances were grown in a common garden with or without pathogen inoculation. Disease development and physiological performance of plants were monitored during an initial irrigated and subsequent terminal drought period. Provenances from drier regions were more susceptible to the fungal pathogen than those from wetter regions, having on average 31% higher incidence rates at 20 days post‐inoculation (dpi) and larger canker lesions at 130 dpi (on average 49% increase) and 230 dpi (on average 42% increase). However, canker development for each provenance was fastest during the initial irrigated wetter growing period. Overall, the average relative canker growth rate was 4‐fold higher during the irrigated period compared to the terminal drought period ( p .001). There were no significant differences between the provenances in leaf water status, photosynthetic rates, or relative growth rates ( p .05). Canker infection reduced both photosynthetic rates and growth rates but only during the later part of the terminal drought period, with significant ( p .05) reductions observed in two out of eight provenances, when plants had relatively large canker sizes. This effect tended to be strongest in the provenances from drier regions as they had relatively larger canker sizes than the provenances from wetter regions. We propose that the increased susceptibility of drier provenances is related to their lower exposure to the pathogen in their drier habitats. Since this is potentially due to suboptimal defence responses, using provenances from drier locations to ‘future‐proof’ local restoration outcomes in a drying climate may be counterproductive due to plant–pathogen interactions.

Interspecific facilitation of micronutrient uptake between cluster-root-bearing trees and non-cluster rooted-shrubs in a Banksia woodland

Publisher: Springer Science and Business Media LLC

Date: 21-06-2023

DOI: 10.1007/S11104-023-06092-6

Abstract: Belowground interspecific plant facilitation is supposed to play a key role in enabling species co-existence in hyper erse ecosystems in extremely nutrient-poor, semi-arid habitats, such as Banksia woodlands in southwestern-Australia. Manganese (Mn) is readily mobilised by Banksia cluster root activity in most soils and accumulates in mature leaves of native Australian plant species without significant remobilisation during leaf senescence. We hypothesised that neighbouring shrubs are facilitated in terms of Mn uptake depending on distance to surrounding cluster root-forming Banksia trees. We mapped all Banksia trees and selected neighbouring shrubs within a study site in Western Australia. Soil s les were collected and analysed for physical properties and nutrient concentrations. To assesses the effect of Banksia tree proximity on leaf Mn concentrations [Mn] of non-cluster-rooted woody shrubs, s les of similarly aged leaves were taken. We used multiple linear models to test for factors affecting shrub leaf [Mn]. None of the assessed soil parameters showed a significant correlation with shrub leaf Mn concentrations. However, we observed a significant positive effect of very close Banksia trees (2 m) on leaf [Mn] in one of the understorey shrubs. We found additional effects of elevation and shrub size. Leaf micronutrient concentrations of understorey shrubs were enhanced when growing within 2 m of tall Banksia trees. Our model predictions also indicate that belowground facilitation of Mn uptake was shrub size-dependent. We discuss this result in the light of plant water relations and shrub root system architecture.

Potassium Fertilisation Is Required to Sustain Cassava Yield and Soil Fertility

Publisher: MDPI AG

Date: 30-07-2020

DOI: 10.3390/AGRONOMY10081103

Abstract: Cassava is often grown in low-fertility soils and has a reputation for having modest nutrient requirements. The storage roots that are harvested, however, contain relatively large amounts of potassium (K). We carried out a field experiment in Laos to determine the growth response to K fertiliser and to examine the field’s K balance over the cropping season. Four different rates of K (0-40-80-120 kg K2O equivalents ha−1) were applied to cassava variety Rayong11. Harvests were done at 8 and 10 months after planting, when the crop was at early and full maturity respectively, to assess if any benefits for productivity or K balance could be achieved by early harvest. We found a positive effect of K fertiliser (up to 39% yield increase compared to no K fertiliser at early harvest, 21% at late harvest) and a positive effect of late harvest (on average a 35% increase compared to early harvest) on cassava root yield. Low-K crops benefited more from a late harvest. At 10 months, the harvested cassava contained 99–142 kg K ha−1, indicating that there was a net removal of K from the fields, even at high K fertilisation levels. This experiment was carried out in comparatively fertile soil with relatively high background K levels, yet, yield benefits of K fertilisation were observed and soil K reserves were depleted by the harvest. It can be concluded that K fertilisation of cassava is advisable for better yields and to avoid progressive depletion of the soil K capital.

Individual tree growth in jarrah (Eucalyptus marginata) forest is explained by size and distance of neighbouring trees in thinned and non-thinned plots

Publisher: Elsevier BV

Date: 08-2011

DOI: 10.1016/J.FORECO.2021.119364

Effect of thinning and fertilizer on growth and allometry of Eucalyptus marginata

Publisher: Elsevier BV

Date: 2021

DOI: 10.1016/J.FORECO.2020.118594

Linkage Projects - Grant ID: LP150100339

Start Date: 12-2015

End Date: 12-2018

Amount: $354,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP0985685

Start Date: 2009

End Date: 12-2013

Amount: $315,000.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP0882350

Start Date: 04-2008

End Date: 2012

Amount: $312,858.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP120200581

Start Date: 07-2012

End Date: 12-2016

Amount: $275,000.00

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE0989071

Start Date: 01-2009

End Date: 07-2012

Amount: $600,000.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP0211478

Start Date: 03-2002

End Date: 12-2005

Amount: $67,635.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP0669757

Start Date: 11-2006

End Date: 11-2011

Amount: $631,000.00

Funder: Australian Research Council

Industrial Transformation Training Centres - Grant ID: IC150100041

Start Date: 06-2016

End Date: 12-2021

Amount: $4,961,622.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP0347692

Start Date: 06-2003

End Date: 05-2006

Amount: $125,000.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP140100736

Start Date: 02-2015

End Date: 04-2019

Amount: $300,000.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP0774881

Start Date: 06-2007

End Date: 03-2012

Amount: $1,028,287.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP190100051

Start Date: 11-2020

End Date: 12-2023

Amount: $439,000.00

Funder: Australian Research Council