Assessing the value of trees in sustainable grazing systems

The retention of trees in strips provides an option for managing non-remnant woody vegetation in native and sown pastures in northern Australia. However, the impact of tree strips on pasture production has not been previously researched in detail in southern Queensland. The influence of existing tree strips on pasture production in southern Queensland was measured at three grazing properties during 2004 and 2005. Soil and pasture attributes were sampled along transects 80 to 300 metres in length positioned perpendicular to tree strips. The tree strips ranged from 15 to 75 metres wide and were 120 to 500 metres apart. The effects of tree strips along the pasture transect were quantified in terms of pasture microclimate (e.g. temperature, humidity and, at one location, wind), pasture growth in grazed and exclosed situations, soil water, soil nutrients and condition, and nutrient availability. An experimental approach using exclosed pasture transects provided a useful ‘bioassay’ potentially integrating beneficial and competitive effects of tree strips on pasture growth as well as other factors (e.g. soil variability). Averaged across two locations and two years, the competitive effects of the tree strip were compensated to some extent by enhanced pasture growth at distances of 1-6 x tree height from the tree strip edge. However, the observed effects on pasture growth along the transect were likely to be due to different causes: pasture microclimate at one site, soil texture and microtopography at a second site and pasture establishment history at a third site. Thus, the trial highlighted the difficulty of attributing effects in real-world situations, given the number of possible causes including the tree strip effects on pasture microclimate and nutrient availability, soil surface disturbance, and systematic variation on soil and water redistribution due to soil micro-topography and felled timber. Despite these many sources of variation, general effects were derived from the field data consistent with other studies on tree strips and wind breaks across Australia. To extrapolate the project results to other locations, tree strip configurations and climates, a new version of the soil waterpasture growth simulation model GRASP was developed allowing simulation of tree and pasture effects and processes for various distances along a pasture transect perpendicular from the tree strip

The Grizzly, May 3, 1985

Reimert Hall Will Welcome Girls in the Fall • Fraternities Are Still Alive at Ursinus • Ursinus Applicants Improve • Letters: Greek Week Disappointing; Radio Offers Thanks • Drinking Age of 21 Should Not Be a Standard • Profile: Dr. Coggers Says Farewell • Greek Week\u27s Final Results • Lacrosse Looks to Repeat Division III Title • Successful Year for Lacrosse Club • Gasser Retires • Sally Grim Shines As Star Pitcher • Griffin Worth Far More than Gold • Trackmen Head to MAC\u27s • Stormy Baver is Pilot Behind the Plate • Golf Team Optimistic • Visit the Writing Center • 1985 Baseball Wraps it Up • 1985 Lacrosse Stats • St. Joseph\u27s M.B.A Courses Offered at Ursinus • Open Dialog On Intervention • Area Residents Share College Memories • Shorts: Faculty Members to Retire; Open Dialog; Color Analysis Held on Campus; Evening Concert Announced; Voices ; Art Show • Dead Kennedys • WVOU Conducts Survey • Luau on Sat. • Weekend Highlights • It Will Be a Fantasy Weekendhttps://digitalcommons.ursinus.edu/grizzlynews/1142/thumbnail.jp

Pasture degradation and recovery in Australia's rangelands: learning from history

"The extended drought periods in each degradation episode have provided a test of the capacity of grazing systems (i.e. land, plants, animals, humans and social structure) to handle stress. Evidence that degradation was already occurring was identified prior to the extended drought sequences. The sequence of dry years, ranging from two to eight years, exposed and/or amplified the degradation processes. The unequivocal evidence was provided by: (a) the physical 'horror' of bare landscapes, erosion scalds and gullies and dust storms; (b) the biological devastation of woody weeds and animal suffering/deaths or forced sales, and; (c) the financial and emotional plight of graziers and their families due to reduced production in some cases leading to abandonment of properties or, sadly, deaths (e.g. McDonald 1991, Ker Conway 1989)."--Publisher websit

Climate variability, climate change and land degradation

Effective response by government and individuals to the risk of land degradation requires an understanding of regional climate variations and the impacts of climate and management on condition and productivity of land and vegetation resources. Analysis of past land degradation and climate variability provides some understanding of vulnerability to current and future climate changes and the information needs for more sustainable management. We describe experience in providing climate risk assessment information for managing for the risk of land degradation in north-eastern Australian arid and semi-arid regions used for extensive grazing. However, we note that information based on historical climate variability, which has been relied on in the past, will now also have to factor in the influence of human-induced climate change. Examples illustrate trends in climate for Australia over the past decade and the impacts on indicators of resource condition. The analysis highlights the benefits of insights into past trends and variability in rainfall and other climate variables based on extended historic databases. This understanding in turn supports more reliable regional climate projections and decision support information for governments and land managers to better manage the risk of land degradation now and in the future

Native pastures and beef cattle show a spatially variable response to a changing climate in Queensland, Australia

Queensland's rangelands are an important source for Australia's pastoral food production. However, they are subject to significant climate variability and will be under increasing pressure as the climate changes, potentially leading to loss of productivity. Pasture growth fluctuates greatly due to rainfall variability, which unfortunately is the climate variable with the largest uncertainties in future projections for northern and eastern Australia. This sensitivity study examines the effect of climate change and its interaction with soil fertility and trees on pasture and livestock production in Queensland. Nine climate change sensitivities were tested in various combinations; an increase in air temperatures by a median projected value of +3 °C, rainfall changes of -20 %, -10 % and +10 % and an increase of carbon dioxide concentrations to 700 ppm. The GRASP model was used to assess the responses of pasture growth, pasture quality and cattle liveweight change per head. The most arid areas in western and south-western Queensland were the most sensitive to changes in rainfall. In contrast, the tropical north was the most resilient region. Southern and south-eastern Queensland benefitted from higher air temperatures producing greater pasture growth, quality and liveweight gain per head by extending the growing season and reducing frost during the winter months. The presence of trees competing for water and nitrogen increased the sensitivity of pasture to climate change, especially at higher carbon dioxide levels and lower rainfall. Increased carbon dioxide enhanced pasture growth and mitigated rainfall reductions by improving the water use efficiency of the plants. Thus, a warmer climate may create new opportunities in the south and south-east, but a warmer and drier climate in the western regions of Queensland is likely to reduce pasture and livestock production

Analysis of soil carbon outcomes from interaction between climate and grazing pressure in Australian rangelands using Range-ASSESS

This paper uses a scenario analysis system - Range-ASSESS - to examine the potential for gains and losses of soil carbon in the Australian rangelands as affected by grazing and climate. The analysis involves a factorial examination of the effect of stocking rates and all possible 5-year historical climates between 1889 and 1999. The analysis also looks at the sensitivity of results to the method of calculation of safe carrying capacity, and to the thresholds used to calculate grazing and dryness indices that drive transitions in state and transition models. The analysis showed that different vegetation zones produced different responses to changes in stocking depending upon the spatial distribution of dryness index, nature of carbon state and transition model, rules governing transitions, and relative significance of soil carbon. At a stocking density equivalent to 100% of 1997 levels, the soil carbon loss from rangelands was about 400 Mt C in 40% of the 5-year periods using a sensitive growth deviation threshold to determine dryness index. If a less sensitive threshold was used, potential loss was reduced to about 200 Mt C. If the grazing pressure threshold for a grazing index of four is adjusted to a more generous level, then potential losses in the dry periods are substantially reduced. The analysis is intended to be indicative of a likely approximate outcome rather than a quantitative measure of system response. The results indicate that the interpretation of the effect of the drought-grazing pressure interaction on perennial plant survival, and consequent organic carbon input to soils, is a major source of uncertainty and a critical area for more experimental measurement. (C) 2005 Elsevier Ltd. All rights reserved

Modeling vegetation, carbon, and nutrient dynamics in the savanna woodlands of Australia with the AussieGRASS Model

Models of savanna and grassland systems in Australia are used for two distinct aims. The first aim is an applied operational role, where models are run in near real-time and results are used to address the information needs of public policy decisions, for example, drought situation analysis; State of Environment reporting; and provision of climate risk assessments of pasture resources for tactical management of grazing and fire. The second aim is to improve the scientific understanding of processes and to simulate the likely long-term outcomes and risks of current management practices for strategic policy and planning purposes. AussieGRASS (Carter et aI., 2000) provides a simulation of the soil water balance and pasture dry matter fluxes over the Australian continent. Simulations are spatial and are performed on individual grid cells (approximately 5 km x 5 km) across Australia. AussieGRASS uses a version of the GRASP model (Rickert et aI., 2000) and simulates the hydrology and dry matter flow of pasture communities at a daily time step. It includes, as gridded inputs (5 km x 5 km), information layers of daily climate data, soil attributes (e.g., plant available water range), tree cover, pasture community, and densities of grazing animals (i.e., domestic livestock, feral and native herbivores). The information layers of soil type and pasture community allow specification of parameters for available water range of four soil layers and pasture attributes affecting plant growth, senescence, detachment, and decomposition. A key feature of GRASP is that hydrological processes such as pasture transpiration and runoff are driven by dynamic groundcover estimates that are updated daily. Thus, AussieGRASS is a dynamic model, responding to daily variation in climatic variables and moderated by management, fire, and herbivory

The climate change risk management matrix for the grazing industry of northern Australia

The complexity, variability and vastness of the northern Australian rangelands make it difficult to assess the risks associated with climate change. In this paper we present a methodology to help industry and primary producers assess risks associated with climate change and to assess the effectiveness of adaptation options in managing those risks. Our assessment involved three steps. Initially, the impacts and adaptation responses were documented in matrices by 'experts' (rangeland and climate scientists). Then, a modified risk management framework was used to develop risk management matrices that identified important impacts, areas of greatest vulnerability (combination of potential impact and adaptive capacity) and priority areas for action at the industry level. The process was easy to implement and useful for arranging and analysing large amounts of information (both complex and interacting). Lastly, regional extension officers (after minimal 'climate literacy' training) could build on existing knowledge provided here and implement the risk management process in workshops with rangeland land managers. Their participation is likely to identify relevant and robust adaptive responses that are most likely to be included in regional and property management decisions. The process developed here for the grazing industry could be modified and used in other industries and sectors. By 2030, some areas of northern Australia will experience more droughts and lower summer rainfall. This poses a serious threat to the rangelands. Although the impacts and adaptive responses will vary between ecological and geographic systems, climate change is expected to have noticeable detrimental effects: reduced pasture growth and surface water availability; increased competition from woody vegetation; decreased production per head (beef and wool) and gross margin; and adverse impacts on biodiversity. Further research and development is needed to identify the most vulnerable regions, and to inform policy in time to facilitate transitional change and enable land managers to implement those changes

Geomorphology, Active Tectonics, and Landscape Evolution in the Mid-Atlantic Region

In 2014, the geomorphology community marked the 125th birthday of one of its most influential papers, ‘The Rivers and Valleys of Pennsylvania’ by William Morris Davis. Inspired by Davis’s work, the Appalachian landscape rapidly became fertile ground for the development and testing of several grand landscape evolution paradigms, culminating with John Hack’s dynamic equilibrium in 1960. As part of the 2015 GSA Annual Meeting, the Geomorphology, Active Tectonics, and Landscape Evolution field trip offers an excellent venue for exploring Appalachian geomorphology through the lens of the Appalachian landscape, leveraging exciting research by a new generation of process-oriented geomorphologists and geologic field mapping. Important geomorphologic scholarship has recently used the Appalachian landscape as the testing ground for ideas on long- and short-term erosion, dynamic topography, glacial-isostatic adjustments, active tectonics in an intraplate setting, river incision, periglacial processes, and soil-saprolite formation. This field trip explores a geologic and geomorphic transect of the mid-Atlantic margin, starting in the Blue Ridge of Virginia and proceeding to the east across the Piedmont to the Coastal Plain. The emphasis here will not only be on the geomorphology, but also the underlying geology that establishes the template and foundation upon which surface processes have etched out the familiar Appalachian landscape. The first day focuses on new and published work that highlights Cenozoic sedimentary deposits, soils, paleosols, and geomorphic markers (terraces and knickpoints) that are being used to reconstruct a late Cenozoic history of erosion, deposition, climate change, and active tectonics. The second day is similarly devoted to new and published work documenting the fluvial geomorphic response to active tectonics in the Central Virginia seismic zone (CVSZ), site of the 2011 M 5.8 Mineral earthquake and the integrated record of Appalachian erosion preserved on the Coastal Plain. The trip concludes on Day 3, joining the Kirk Bryan Field Trip at Great Falls, Virginia/Maryland, to explore and discuss the dramatic processes of base-level fall, fluvial incision, and knickpoint retreat

The coming global economic downturn and suicide: a call to action

No abstract available