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Describing and classifying a landscape for environmental impact and risk assessment purposes is a non-trivial challenge because this requires region-specific landscape classifications that cater for region-specific impacts. Assessing impacts on ecosystems from the extraction of water resources across large regions requires a causal link between landscape features and their water requirements. We present the rationale and implementation of an ecohydrological classification for regions where coal mine and coal seam gas developments may impact on water. Our classification provides the essential framework for modelling the potential impact of hydrological changes from future coal resource developments at the landscape level. We develop an attribute-based system that provides representations of the ecohydrological entities and their connection to landscape features and make use of existing broad-level classification schemes into an attribute-based system. We incorporate a rule set with prioritisation, which underpins risk modelling and makes the scheme resource efficient, where spatial landscape or ecosystem classification schemes, developed for other purposes, already exist. A consistent rule set and conceptualised landscape processes and functions allow for the combination of diverse data with existing classification schemes. This makes the classification transparent, repeatable and adjustable, should new data become available. We apply the approach in three geographically different regions, with widely disparate information sources, for the classification, and provide a detailed example of its application. We propose that it is widely applicable around the world for linking ecohydrology to environmental impacts. [ABSTRACT FROM AUTHOR]

Describing and classifying a landscape for environmental impact and risk assessment purposes is a non-trivial challenge, as standard landscape classifications that cater for region specific impacts do not exist. Assessing impacts on ecosystems from extraction of water resources across large regions requires linking of landscape features to their water requirements. We present the rationale and implementation of an ecohydrological classification for regions where coal mine and coal seam gas developments may impact on water. Our classification provides the essential framework for modelling the potential impact of hydrological changes from future coal resource developments at the landscape level. We develop an attribute-based system that provides representations of the ecohydrological entities and their connection to landscape features and make use of existing broad-level, classification schemes into an attribute20 based system. We incorporate a rule-set with prioritisation, which underpin risk modelling and make the scheme resource efficient, where spatial landscape or ecosystem classification schemes, developed for other purposes, already exist. - A consistent rule-set and conceptualised landscape processes and functions allow combining diverse data with existing classification schemes. This makes the classification transparent, repeatable, and adjustable, should new data become available. We apply the approach in three geographically different regions, with widely disparate information sources for the classification and provide a detailed example of its application. We propose that it is widely applicable around the world for linking ecohydrology to environmental impacts. [ABSTRACT FROM AUTHOR]

Agroforestry is one nature-based solution that holds significant potential for improving the sustainability and resilience of agricultural systems. Quantifying these benefits is challenging in agroforestry systems, largely due to landscape complexity and the diversity of management approaches. Digital tools designed for agroforestry typically focus on timber and crop production, and not the broader range of benefits usually considered in assessments of ecosystem services and natural capital. The objectives of this review were to identify and evaluate digital tools that quantify natural capital benefits across eight themes applicable to agroforestry systems: timber production and carbon sequestration, agricultural production, microclimate, air quality, water management, biodiversity, pollination, and amenity. We identified and evaluated 63 tools, 9 of which were assessed in further detail using Australia as a case study. No single tool was best suited to quantify benefits across each theme, suggesting that multiple tools or models could be combined to address capability gaps. We find that model complexity, incorporation of spatial processes, accessibility, regional applicability, development speed and interoperability present significant challenges for the tools that were evaluated. We recommend that these challenges be considered as opportunities to develop new, and build upon existing, tools to enhance decision support in agroforestry systems. [ABSTRACT FROM AUTHOR]

Abstract Background The Tissue Microarray (TMA) facilitates high-throughput analysis of hundreds of tissue specimens simultaneously. However, bottlenecks in the storage and manipulation of the data generated from TMA reviews have become apparent. A number of software applications have been developed to assist in image and data management; however no solution currently facilitates the easy online review, scoring and subsequent storage of images and data associated with TMA experimentation. Results This paper describes the design, development and validation of the Virtual Tissue Matrix (VTM). Through an intuitive HTML driven user interface, the VTM provides digital/virtual slide based images of each TMA core and a means to record observations on each TMA spot. Data generated from a TMA review is stored in an associated relational database, which facilitates the use of flexible scoring forms. The system allows multiple users to record their interpretation of each TMA spot for any parameters assessed. Images generated for the VTM were captured using a standard background lighting intensity and corrective algorithms were applied to each image to eliminate any background lighting hue inconsistencies or vignetting. Validation of the VTM involved examination of inter-and intra-observer variability between microscope and digital TMA reviews. Six bladder TMAs were immunohistochemically stained for E-Cadherin, β-Catenin and PhosphoMet and were assessed by two reviewers for the amount of core and tumour present, the amount and intensity of membrane, cytoplasmic and nuclear staining. Conclusion Results show that digital VTM images are representative of the original tissue viewed with a microscope. There were equivalent levels of inter-and intra-observer agreement for five out of the eight parameters assessed. Results also suggest that digital reviews may correct potential problems experienced when reviewing TMAs using a microscope, for example, removal of background lighting variance and tint, and potential disorientation of the reviewer, which may have resulted in the discrepancies evident in the remaining three parameters.

Rising levels of atmospheric CO2 concentration ( Ca) and simultaneous climate change profoundly affect plant physiological performance while challenging our ability to estimate vegetation-atmosphere fluxes. To predict rates of water and carbon exchange between vegetation and the atmosphere, we require a formulation for stomatal conductance ( gs) that captures the multidimensional response of stomata to changing environmental conditions. The unified stomatal optimization (USO) theory provides a formulation for gs with the ability to predict the response of gs to novel environmental conditions such as elevated Ca (e Ca), warmer temperatures and/or changing water availability., We tested for the effect of e Ca and seasonally varying climate on stomatal behaviour, as defined by the USO theory, during the first year of free-air CO2 enrichment in a native eucalypt woodland (the EucFACE experiment). We hypothesized that under e Ca, gs would decrease and photosynthesis ( Anet) would increase, but fundamental stomatal behaviour described in the USO model would remain unchanged. We also predicted that the USO slope parameter g1 would increase with temperature and water availability. Over 20 months, we performed quarterly gas exchange campaigns encompassing a wide range of temperatures and water availabilities. We measured gs, Anet and leaf water potential (Ψ) at mid-morning, midday and pre-dawn (Ψ only) under ambient and e Ca and prevailing climatic conditions, at the tree tops (20 m height)., We found that e Ca induced a 20% reduction in stomatal conductance under non-limiting water availability, enhanced mid-morning Anet by 24% in three out of five measurement campaigns and had no significant effect on Ψ. The parameter g1 was conserved under e Ca, weakly increased with temperature and did not respond to increasing water availability., Our results suggest that under e Ca and variable rainfall, mature eucalypt trees exhibit a conservative water-use strategy, but this strategy may be modified by growth temperature. We show that the USO theory successfully predicts coupling of carbon uptake and water loss in future atmospheric conditions in a native woodland and thus could be incorporated into ecosystem-scale and global vegetation models. [ABSTRACT FROM AUTHOR]

Future climate regimes characterized by rising [CO2], rising temperatures and associated droughts may differentially affect tree growth and physiology. However, the interactive effects of these three factors are complex because elevated [CO2] and elevated temperature may generate differential physiological responses during drought. To date, the interactive effects of elevated [CO2] and elevated temperature on drought-induced tree mortality remain poorly understood in gymnosperm species that differ in stomatal regulation strategies. Water relations and carbon dynamics were examined in two species with contrasting stomatal regulation strategies: Pinus radiata D. Don (relatively isohydric gymnosperm; regulating stomata to maintain leaf water potential above critical thresholds) and Callitris rhomboidea R. Br (relatively anisohydric gymnosperm; allowing leaf water potential to decline as the soil dries), to assess response to drought as a function of [CO2] and temperature. Both species were grown in two [CO2] (Ca (ambient, 400 μl l-1) and Ce (elevated, 640 μl l-1)) and two temperature (Ta (ambient) and Te (ambient +4 °C)) treatments in a sun-lit glasshouse under well-watered conditions. Drought plants were then exposed to a progressive drought until mortality. Prior to mortality, extensive xylem cavitation occurred in both species, but significant depletion of non-structural carbohydrates was not observed in either species. Te resulted in faster mortality in P. radiata, but it did not modify the time-to-mortality in C. rhomboidea. Ce did not delay the time-to-mortality in either species under drought or Te treatments. In summary, elevated temperature (+4 °C) had greater influence than elevated [CO2] (+240 μl l-1) on drought responses of the two studied gymnosperm species, while stomatal regulation strategies did not generally affect the relative contributions of hydraulic failure and carbohydrate depletion to mortality under severe drought. [ABSTRACT FROM AUTHOR]

Successful management of forest systems requires a deeper understanding of the role of ecophysiological traits in enabling adaptation to high temperature and water deficit under current and anticipated changes in climate. A key attribute of leaf water relations is the water potential at zero turgor (πtlp), because it defines the operating water potentials over which plants actively control growth and gas exchange. This study examines the drivers of variation in πtlp with respect to species climate of origin and habitat water availability. We compiled a water relations database for 174 woody species occupying clearly delineated gradients in temperature and precipitation across the Australian continent. A significant proportion of the variability in πtlp (∼35%) could be explained by climatic water deficit and its interaction with summertime maximum temperature, demonstrating the strong selective pressure of aridity and high temperature in shaping leaf water relations among Australian species. Habitat water availability (midday leaf water potential), was also a significant predictor of πtlp (R² = 0.43), highlighting the importance of species ecohydrologic niche under a set of climatic conditions. Shifts in πtlp in response to both climatic and site-based drivers of water availability emphasises its adaptive significance and its suitability as a predictor of plant performance under future climatic change. [ABSTRACT FROM AUTHOR]

Elevated [CO2] and temperature may alter the drought responses of tree seedling growth, photosynthesis, respiration and total non-structural carbohydrate (TNC) status depending on drought intensity and duration. Few studies have addressed these important climatic interactions or their consequences. We grew Eucalyptus globulus Labill. seedlings in two [CO2] concentrations (400 and 640 μl l−1) and two temperatures (28/17 and 32/21 °C) (day/night) in a sun-lit glasshouse, and grew them in well-watered conditions or exposed them to two drought treatments having undergone different previous water conditions (i.e., rewatered drought and sustained drought). Progressive drought in both drought treatments led to similar limitations in growth, photosynthesis and respiration, but reductions in TNC concentration were not observed. Elevated [CO2] ameliorated the impact of the drought during the moderate drought phase (i.e., Day 63 to Day 79) by increasing photosynthesis and enhancing leaf and whole-plant TNC content. In contrast, elevated temperature exacerbated the impact of the drought during the moderate drought phase by reducing photosynthesis, increasing leaf respiration and decreasing whole-plant TNC content. Extreme drought (i.e., Day 79 to Day 103) eliminated [CO2] and temperature effects on plant growth, photosynthesis and respiration. The combined effects of elevated [CO2] and elevated temperature on moderate drought stressed seedlings were reduced with progressive drought, with no sustained effects on growth despite greater whole-plant TNC content. [ABSTRACT FROM PUBLISHER]

Plant survival during drought requires adequate hydration in living tissues and carbohydrate reserves for maintenance and recovery. We hypothesized that tree growth and hydraulic strategy determines the intensity and duration of the 'physiological drought', thereby affecting the relative contributions of loss of hydraulic function and carbohydrate depletion during mortality., We compared patterns in growth rate, water relations, gas exchange and carbohydrate dynamics in three tree species subjected to prolonged drought., Two Eucalyptus species ( E. globulus, E. smithii) exhibited high growth rates and water-use resulting in rapid declines in water status and hydraulic conductance. In contrast, conservative growth and water relations in Pinus radiata resulted in longer periods of negative carbon balance and significant depletion of stored carbohydrates in all organs. The ongoing demand for carbohydrates from sustained respiration highlighted the role that duration of drought plays in facilitating carbohydrate consumption., Two drought strategies were revealed, differentiated by plant regulation of water status: plants maximized gas exchange, but were exposed to low water potentials and rapid hydraulic dysfunction; and tight regulation of gas exchange at the cost of carbohydrate depletion. These findings provide evidence for a relationship between hydraulic regulation of water status and carbohydrate depletion during terminal drought. [ABSTRACT FROM AUTHOR]

Early weed control may improve the growth of forest plantations by influencing soil water and nutrient availability. To understand eucalypt growth responses to weed control, we examined the temporal responses of leaf gas-exchange, leaf nitrogen concentration (N) and water status of 7-month-old Eucalyptus globulus L. trees in a paired-plot field trial. In addition, we monitored the growth, leaf N and water status of the competing vegetation in the weed treatment. By the end of the 11-month experiment, complete weed control (WF treatment) of largely woody competitors increased the basal diameter of E. globulus by 14%. As indicated by pre-dawn water potentials of >- 0.05 MPa, interspecies competition for water resources was minimal at this site. In contrast, competition for N appeared to be the major factor limiting growth. Estimations of total plot leaf N (g m-2 ground) showed that competing vegetation accounted for up to 70% of the total leaf N at the start of the trial. This value fell to 15% by the end of the trial. Despite increased leaf Narea in WF trees 5 months after imposition of weed control, the photosynthetic capacity (A1500) of E. globulus was unaffected by treatment suggesting that the growth gains from weed control were largely unrelated to changes in leaf-level photosynthesis. Increased nutrient availability brought about by weed control enabled trees to increase investment into leaf-area production. Estimates of whole-tree carbon budget based on direct measurements of dark respiration and A1500 allowed us to clearly demonstrate the importance of leaf area driving greater productivity following early weed control in a nutrient-limited site. [ABSTRACT FROM AUTHOR]

Forest canopies exchange a large part of the mass and energy between the earth and the atmosphere. The processes that regulate these exchanges have been of interest to scientists from a diverse range of disciplines for a long time. The International Union of Forest Research Organizations (IUFRO) Canopy Processes Working Group provides a forum for these scientists to explore canopy processes at scales ranging from the leaf to the ecosystem. Given the changes in climate that are being experienced in response to rising [CO2], there is a need to understand how forest canopy processes respond to altered environments. Globally, native and managed forests represent the largest terrestrial biome and, in wood and soils, the largest terrestrial stores of carbon. Changing climates have significant implications for carbon storage in forests, as well as their water use, species diversity and management. In order to address these issues, the Canopy Processes Working Group held a travelling workshop in south-east Australia during October 2010 to examine the impact of changing climates on forest canopies, highlighting knowledge gaps and developing new research directions. [ABSTRACT FROM AUTHOR]

Increasing drought frequency is a major driver of changes in forest structure and has been implicated in the decline of the endangered tree species, Eucalyptus gunnii ssp. divaricata (McAulay & Brett) in the Central Plateau region of Tasmania, Australia. In this study, we examined patterns of regeneration, aspects of the water relations of E. gunnii ssp. divaricata and its replacement Eucalyptus pauciflora and, whether shifts in stand dominance have occurred where the subspecies co-occurs with E. pauciflora could be related to recent changes in climate. Successful E. gunnii ssp. divaricata seedling regeneration was restricted to micro-sites with relatively deep soils within slight depressions. In contrast, poor E. gunnii ssp. divaricata regeneration and declining adult cohorts of this species all occurred on steeper, concave micro-sites with shallow soils. This apparent shift in suitable regeneration micro-site, from sites with shallow to deeper soils, may be linked to an observed 25% reduction in summer rainfall over the last 50 years. On slopes surrounding waterlogged depressions where E. gunnii ssp. divaricata co-occurs with E. pauciflora, E. pauciflora was in higher abundance than E. gunnii ssp. divaricata in small adult and sapling size-classes, compared with the adult cohorts (>30 cm d.b.h.), a trend consistent with a shift in stand dominance. Despite existing paradigms related to differential drought tolerance between these two species as a driver of this shift in stand dominance, there were no differences in predawn ( Ψpd) water potentials between species. Furthermore, pressure-volume analysis showed that E. gunnii ssp. divaricata had lower values for osmotic potential at turgor loss point (−2.33 ± 0.06 MPa) than E. pauciflora (−2.13 ± 0.03 MPa), suggesting that E. gunnii ssp. divaricata may be more drought tolerant than E. pauciflora, in contrast to the prevailing paradigm that it is more susceptible to drought than E. pauciflora. [ABSTRACT FROM AUTHOR]

We tested the ability of a model to scale gas exchange from leaf level to whole-tree level by: (1) measuring leaf gas exchange in the canopy of 10 trees in a tall Eucalyptus delegatensis RT Baker forest in NSW, Australia; (2) monitoring sap flow of the same 10 trees during the measurement week; and (3) using an individual-tree-based model (MAESTRA) to link the two sets of measurements. Photosynthesis and stomatal conductance components of the model were parameterized with the leaf gas exchange data, and canopy structure was parameterized with crown heights, dimensions and leaf areas of each of the measurement trees and up to 45 neighboring trees. Transpiration of the measurement trees was predicted by the model and compared with sap flow data. Leaf gas exchange parameters were similar for all 10 trees, with the exception of two smaller trees that had relatively low stomatal conductances. We hypothesize that these trees may have experienced water stress as a result of competition from large neighboring trees. The model performed well, and in most cases, was able to replicate the time course of tree transpiration. Maximum rates of transpiration were higher than measured rates for some trees and lower than measured rates for others, which may have been a result of inaccuracy in estimating tree leaf area. There was a small lag (about 15-30 minutes) between sap flow and modeled transpiration for some trees in the morning, likely associated with use of water stored in stems. The model also captured patterns of variation in sap flow among trees. Overall, the study confirms the ability of models to estimate forest canopy transpiration from leaf-level measurements. [ABSTRACT FROM AUTHOR]

Daily and seasonal fluxes of carbon dioxide and water vapor above a north Australian savanna were recorded over a complete dry season–wet season annual cycle using the eddy covariance technique. Wet season rates of photosynthesis and transpiration were larger than those measured in the dry season and were dominated by the presence of the grassy understory. As the dry season progressed and the grass understory died, ecosystem rates of assimilation and water vapor flux declined substantially. By the end of the dry season, canopy assimilation and evapotranspiration rates were 20–25% of wet season values. Assimilation was light saturated in the dry season but not in the wet season. Stomatal control of transpiration increased between the wet and dry season. This was revealed by the decline in the slope of E with increasing leaf-to-air vapor pressure difference (D) between wet and dry seasons, and also by the significant decrease in the ratio of boundary to canopy conductance observed between the wet and dry seasons. A simple pan-tropical modeling of leaf area index or wet season canopy CO2 flux was undertaken. It was shown that with readily available data for foliar N content and the ratio of rainfall to potential evaporation, leaf index and wet season canopy CO2 flux can be successfully estimated for a number of tropical ecosystems, including north Australian savannas. [ABSTRACT FROM AUTHOR]