Wayne S. Meyer

Landscape futures analysis: Assessing the impacts of environmental targets under alternative spatial policy options and future scenarios

Environmental targets are often used in planning for sustainable agricultural landscapes but their impacts are rarely known. In this paper we introduce landscape futures analysis as a method which combines linear programming optimisation with scenario analysis in quantifying the environmental, economic, and social impacts associated with achieving environmental targets, on a landscape scale. We applied the technique in the Lower Murray in southern Australia. Landscape futures models were used to identify specific geographic locations in the landscape for six natural resource management (NRM) actions such that regional environmental targets are achieved. The six potential NRM actions that may be undertaken to achieve environmental targets include remnant vegetation management, ecological restoration, conservation farming, deep-rooted perennials, and the production of biomass and biofuels feedstock for renewable energy generation. We developed landscape futures under four alternative spatial prioritisation policy options and four future climate and commodity price scenarios. The impacts of each landscape future were calculated across a range of environmental, economic, and social indicators. The external drivers, climate change and commodity prices, and internal decisions such as policy options for spatially prioritising NRM actions, both have a strong influence on the costs and benefits of achieving environmental targets. Illustrative results for the cleared agricultural areas in the Mallee region indicate that whilst achieving targets can have substantial environmental benefits, it requires large areas of land use and land management change, and is likely to be costly (up to

Future landscapes: managing within complexity

348.5 M per year) with flow-on impacts on the regional economy and communities. Environmental targets can be achieved more cost-effectively through spatial planning. Costs can be further reduced if markets are established for carbon, biomass, and biofuels to enable landholders to generate income from undertaking NRM. Landscape futures analysis is an effective tool for supporting the strategic regional NRM policy and planning decisions of how best to set and achieve environmental targets.

Real options analysis for land use management: Methods, application, and implications for policy

A regional landscape is a complex social–ecological system comprising a dynamic mosaic of land uses. Management at this scale requires an understanding of the myriad interacting human and natural processes operating on the landscape over a continuum of spatial and temporal scales. Complexity science, which is not part of traditional management approaches, provides a valuable conceptual framework and quantitative tools for dealing with cross-scale interactions and non-linear dynamics in social–ecological systems. Here, we identify concepts and actions arising from complexity science that can be learned and applied by ecosystem managers and discuss how they might be implemented to achieve sustainable future landscapes.

Waterlogging in Australian agricultural landscapes: a review of plant responses and crop models

Discounted cash flow analysis, including net present value is an established way to value land use and management investments which accounts for the time-value of money. However, it provides a static view and assumes passive commitment to an investment strategy when real world land use and management investment decisions are characterised by uncertainty, irreversibility, change, and adaptation. Real options analysis has been proposed as a better valuation method under uncertainty and where the opportunity exists to delay investment decisions, pending more information. We briefly review the use of discounted cash flow methods in land use and management and discuss their benefits and limitations. We then provide an overview of real options analysis, describe the main analytical methods, and summarize its application to land use investment decisions. Real options analysis is largely underutilized in evaluating land use decisions, despite uncertainty in policy and economic drivers, the irreversibility and sunk costs involved. New simulation methods offer the potential for overcoming current technical challenges to implementation as demonstrated with a real options simulation model used to evaluate an agricultural land use decision in South Australia. We conclude that considering option values in future policy design will provide a more realistic assessment of landholder investment decision making and provide insights for improved policy performance.

ERRORS IN FIELD MEASUREMENT OF LEAF DIFFUSIVE CONDUCTANCE ASSOCIATED WITH LEAF TEMPERATURE

Abstract. This review summarises reported observations of the effects of waterlogging on agricultural production in Australia and briefly discusses potential remediation strategies. Inconsistencies are demonstrated in the current indicators used for assessment of waterlogging potential across agricultural landscapes as well as in parameters measured in waterlogging studies. It is suggested that predictions of waterlogging potential for landscapes should be based on a minimum dataset that includes pedological, topographical, and climate data for the defined area, as well as observations of plant morphological appearance and visible surface water. The review also summarises the effects of low oxygen concentration in soil on rhizosphere processes, and discusses evidence for direct effects on plant physiology of reductions in soil oxygen caused by waterlogging. Finally, the review describes current crop growth, water use, and yield simulation models used in Australia (SWAGMAN, DRAINMOD, and APSIM) that incorporate waterlogging stress. It is suggested that there is scope for modifications to these models based on recent improved understanding of plant physiological responses to waterlogging and on further research. The review concludes that improvements in modelling waterlogging outcomes to assist growth and yield predictions should ultimately enhance management capacity for growers.

Drought rapidly diminishes the large net CO2 uptake in 2011 over semi-arid Australia

Meyer, W.S., Reicosky, D.C. and Schaefer, N.L., 1985. Errors in field measurement of leaf diffusive conductance associated with leaf temperature. Agric. For. Meterol., 36: 55--64. The ability of leaf diffusive conductance (CL) measurements to discriminate between different treatments in field studies has generally been disappointing. Since values of C L are sensitive to leaf temperature and temperature gradients between the leaf and air, inaccurate temperature measurements will produce substantial errors. This work compared two methods of leaf temperature measurement from which values of C L were calculated and subsequently compared. Experiments using well-watered field- and glasshouse-grown cotton (Gossypium hirsutum L.) where diffusion porometer readings and leaf temperatures were measured indicated that the porometer thermistor reading differed markedly from leaf temperature as assessed with an infrared thermometer. Under high air vapor pressure deficit (AVPD) conditions (5.2 kPa), leaf temperature (T L) to ambient air temperature • o . (TA) differences were as large as --8 C. Porometer thermistor temperature was strongly influenced by T A and to a lesser extent by T L. Values of C L calculated from porometer measurements of T L can be up to 96% less than true C L values. This is the result of both incorrect T L measurement and a failure to account for the effects of the leaf to porometer-cup temperature differential. Until these two sources of error are addressed, values of C L obtained from diffusion porometer measurements in the field must be regarded as only qualitative.

Future climate and land uses effects on flow and nutrient loads of a Mediterranean catchment in South Australia

Each year, terrestrial ecosystems absorb more than a quarter of the anthropogenic carbon emissions, termed as land carbon sink. An exceptionally large land carbon sink anomaly was recorded in 2011, of which more than half was attributed to Australia. However, the persistence and spatially attribution of this carbon sink remain largely unknown. Here we conducted an observation-based study to characterize the Australian land carbon sink through the novel coupling of satellite retrievals of atmospheric CO2 and photosynthesis and in-situ flux tower measures. We show the 2010–11 carbon sink was primarily ascribed to savannas and grasslands. When all biomes were normalized by rainfall, shrublands however, were most efficient in absorbing carbon. We found the 2010–11 net CO2 uptake was highly transient with rapid dissipation through drought. The size of the 2010–11 carbon sink over Australia (0.97 Pg) was reduced to 0.48 Pg in 2011–12, and was nearly eliminated in 2012–13 (0.08 Pg). We further report evidence of an earlier 2000–01 large net CO2 uptake, demonstrating a repetitive nature of this land carbon sink. Given a significant increasing trend in extreme wet year precipitation over Australia, we suggest that carbon sink episodes will exert greater future impacts on global carbon cycle.

The Australian SuperSite Network: A continental, long-term terrestrial ecosystem observatory

Mediterranean catchments experience already high seasonal variability alternating between dry and wet periods, and are more vulnerable to future climate and land use changes. Quantification of catchment response under future changes is particularly crucial for better water resources management. This study assessed the combined effects of future climate and land use changes on water yield, total nitrogen (TN) and total phosphorus (TP) loads of the Mediterranean Onkaparinga catchment in South Australia by means of the eco-hydrological model SWAT. Six different global climate models (GCMs) under two representative concentration pathways (RCPs) and a hypothetical land use change were used for future simulations. The climate models suggested a high degree of uncertainty, varying seasonally, in both flow and nutrient loads; however, a decreasing trend was observed. Average monthly TN and TP load decreased up to -55% and -56% respectively and were found to be dependent on flow magnitude. The annual and seasonal water yield and nutrient loads may only slightly be affected by envisaged land uses, but significantly altered by intermediate and high emission scenarios, predominantly during the spring season. The combined scenarios indicated the possibility of declining flow in future but nutrient enrichment in summer months, originating mainly from the land use scenario, that may elevate the risk of algal blooms in downstream drinking water reservoir. Hence, careful planning of future water resources in a Mediterranean catchment requires the assessment of combined effects of multiple climate models and land use scenarios on both water quantity and quality.

Simple models for managing complex social-ecological systems

Ecosystem monitoring networks aim to collect data on physical, chemical and biological systems and their interactions that shape the biosphere. Here we introduce the Australian SuperSite Network that, along with complementary facilities of Australias Terrestrial Ecosystem Research Network (TERN), delivers field infrastructure and diverse, ecosystem-related datasets for use by researchers, educators and policy makers. The SuperSite Network uses infrastructure replicated across research sites in different biomes, to allow comparisons across ecosystems and improve scalability of findings to regional, continental and global scales. This conforms with the approaches of other ecosystem monitoring networks such as Critical Zone Observatories, the U.S. National Ecological Observatory Network; Analysis and Experimentation on Ecosystems, Europe; Chinese Ecosystem Research Network; International Long Term Ecological Research network and the United States Long Term Ecological Research Network. The Australian SuperSite Network currently involves 10 SuperSites across a diverse range of biomes, including tropical rainforest, grassland and savanna; wet and dry sclerophyll forest and woodland; and semi-arid grassland, woodland and savanna. The focus of the SuperSite Network is on using vegetation, faunal and biophysical monitoring to develop a process-based understanding of ecosystem function and change in Australian biomes; and to link this with data streams provided by the series of flux towers across the network. The Australian SuperSite Network is also intended to support a range of auxiliary researchers who contribute to the growing body of knowledge within and across the SuperSite Network, public outreach and education to promote environmental awareness and the role of ecosystem monitoring in the management of Australian environments.

Modelling the impacts of altered management practices, land use and climate changes on the water quality of the Millbrook catchment-reservoir system in South Australia

Integrated modelling and assessment can facilitate exploration of complex social-ecological interactions and quantify trade-offs in regional policy, planning, and management options. However, there have been challenges in its acceptance and adoption for supporting decisions. Here we overcome this implementation gap through the development of an interactive online tool called the Landscape Futures Analysis Tool (LFAT) (http://www.lfat.org.au/). Identifying four high priority regional management issues; agricultural production, carbon sequestration, biodiversity conservation and weed management, we developed a series of simple models to explore them through a range of environmental and economic scenarios including climate change, carbon price, agricultural commodity price, and production costs. These models were implemented within the LFAT to allow users to select, query and explore combinations of key variables and examine their impact on each of the management issues through a range of interactive maps and summary statistics. We developed simple models to explore 4 key regional land management issues.Models were implemented in the interactive, online Landscape Futures Analysis Tool.Users can explore key uncertainties in productivity, prices, costs and global change.LFAT provides interactive maps and summary statistics to inform planning.LFAT helps bridge the implementation gap in land management and planning