bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of agricultural management on Vertosols in Tasmania
Authors: Cotching W. E. , Cooper J. , Sparrow L. A. , McCorkell B. E. , Rowley W. , Hawkins K.
Published: March 2003

Attributes of 21 Vertosols in 2 different regions of Tasmania were assessed using field and laboratory techniques to determine differences associated with 3 local forms of agricultural management (long-term pasture, rain-fed cropping and irrigated cropping). Vertosols in the northern Midlands had better physical properties (lesser bulk density and penetration resistance, and greater porosities and water holding capacities), poorer nutrient status (lower pH, exchangeable bases, and extractable P) and better biological properties (greater organic carbon (OC), carbon fractions F1 and F3, and more worms) than south-eastern Vertosols. When adjusted for clay content, cropped sites had less soil OC than pasture sites at 0–75 mm depth. Readily oxidisable (fraction F1) carbon in the surface 75 mm was 3.6 mg/g and 6.9 mg/g under long-term pasture compared with 2.5 mg/g and 3.9 mg/g in irrigated cropped paddocks on south-eastern and Midlands sites, respectively. Soil organic carbon values were positively correlated with physical and chemical soil properties. Long-term pasture paddocks showed stronger structural development and had smaller aggregates than cropped paddocks, which had more larger clods. Vane shear strength and penetration resistance were less in rainfed cropped paddocks compared with long-term pasture but this effect was not apparent on irrigated cropped paddocks. Farmers considered that a majority of their soil attributes were healthy under all management histories but strategies for maintaining organic matter levels and minimising clod formation by tillage are essential for long-term sustainable use of these Vertosols.
Artificial neural network analysis of laboratory and in situ spectra for the estimation of macronutrients in soils of Lop Buri (Thailand)
Authors: Daniel K. W. , Tripathi N. K. , Honda K.
Published: March 2003

Reflectance spectrometry is an emerging and non-destructive detection technique bearing fast, cheap, and accurate results compared with conventional assessments. Most field and laboratory-based spectrometers are restricted to VNIR (visible–near-infrared). However, soils fail to show well-defined narrow absorption bands in this region. This obstructs the use of curve feature as a diagnostic criterion for soil nutrient predictions. In this paper artificial neural network (ANN) is implemented to estimate soil organic matter, phosphorous, and potassium from the VNIR spectrum (400–1100 nm). Macronutrients were modelled from 41 bare soil reflectances of Lop Buri province, Thailand. Neurons were trained from 7 bandwidth categories derived from laboratory-based StellarNet spectroradiometer and in situ photometer. Satisfactory results were attained and compared across different synthesised bandwidths. Models exhibited slightly better estimates from the laboratory than in situ spectra, and from narrower than broader bandwidths. Widening bandwidth corresponds with attenuated predictive powers, coupled with rising errors. Cross validation of models yielded acceptable correlations. The strength of models confirmed the capability of ANN to estimate macronutrients by solving difficulties incurred from high cross-channel correlations prevailing in conventional statistical techniques.
Evaluation of methods for field diagnosis of sodicity in soiland irrigation water in the sugarcane growing districts of Queensland, Australia
Authors: Nelson P. N. , Lawer A. T. , Ham G. J.
Published: March 2003

Sodicity and related properties of soils and irrigation water restrict sugarcane yields and cause environmental problems such as turbid runoff. The aim of this work was to assess the usefulness of several field diagnostic tests for soils and waters of the Australian sugar industry. Tests were evaluated using over 500 soil samples collected from 0–0.75 m depth from the 6 main sugarcane growing districts. Exchangeable sodium percentage (ESP) in the topsoil (0–0.25 m) could be predicted by electromagnetic induction (Geonics EM38) in 2 districts (r2 = 0.64–0.82), and in the subsoil (0.25–0.5 m) in 3 districts (r2�=�0.63–0.86). Dispersion index (DI) was a function of ESP in all districts, with 54–67% of variation accounted for in four districts. Soil pH was a function of ESP in all districts (59–73% of variation accounted for) except Bundaberg. ESP could be predicted from pH, electrical conductivity (EC), and Na concentration (by portable Na-selective electrode) of 1 : 5 soil : water suspensions (r2 = 0.57 for Bundaberg and r2�=�0.66–0.84 in all other districts). In irrigation waters (141 samples), measurements of Na concentration, by portable Na-selective electrode, and EC could be used to estimate Na (r2 = 0.85) and Ca + Mg (r2 = 0.87) concentrations, allowing sodium adsorption ratio to be estimated. Depending on the circumstances, these tests can provide useful estimates of sodicity and related properties in the field.
An improved Victorian erosivity map
Authors: Sheridan G. J. , Rosewell C. J.
Published: March 2003

The impact of raindrops on the soil surface and surface water runoff are two of the agents of soil detachment and sediment transport. The magnitude of these erosion processes is a function of the erosive potential, or erosivity of a rainstorm. The erosivity of rainfall is commonly quantified using the R factor developed for the universal soil loss equation. R is the average of the annual sum of the individual storm erosivity values and can be estimated from published relationships between the storm energy and the rainfall intensity. Currently the most likely source of R-values in Victoria is a hand-drawn contour map produced more than 20 years ago by an expert panel and published in an out-of-print handbook. A new R-value contour map for Victoria is presented, developed from current empirical relationships between rainfall intensity–frequency–duration and R. The R contours vary in value across the state by about a factor of 4, from <800 MJ.mm/ha.h.year in the north-west, to >2700 MJ.mm/ha.h.year in the eastern ranges. The new map improves the resolution and accuracy of erosivity values for Victoria, especially in steeper, forested areas, and will assist in the prediction and modelling of erosion and water quality.
Cadmium accumulation by willow clones used for soil conservation, stock fodder, and phytoremediation
Authors: Granel Thierry , Robinson Brett , Mills Tessa , Clothier Brent , Green Steve , Fung Lindsay
Published: March 2003

Elevated levels of cadmium are often found in the soil of New Zealand pasturelands due to the long-term use of Cd-contaminated fertilisers. The accumulation of Cd in willow biomass used as stock fodder could therefore adversely affect agricultural productivity and human health. Alternatively, willows may be used for phytoremediation of Cd-contaminated soil at polluted sites. An investigation was carried out to determine the variation in Cd as well as Zn, Mn, and Fe accumulation in 15 willow clones that had been bred for soil conservation purposes. These clones were grown under controlled conditions in 20-L pots of soil containing Cd, Zn, Mn, and Fe at concentrations of 0.3, 64, 597, and 56 000 mg/kg, respectively. Daily water use was measured over the final 2 weeks of the experiment and biomass accumulation was determined at the end of the experiment. We found that shrub willows had significantly higher leaf and stem Cd, Mn, and Zn concentrations than tree willows. Average leaf Cd concentrations varied widely between clones from 1.5 to 10 mg/kg. Clones with a high Cd accumulation capacity may be selected to improve the efficacy of Cd-phytoremediation, whereas clones that accumulated lower Cd concentrations may be used for stock fodder. Metal concentrations were not significantly correlated with plant water-use, or biomass production.
Effects of site preparation on runoff, erosion, and nutrient losses from Pinus plantations established on the coastal lowlands of south-east Queensland, Australia
Authors: Costantini A. , Loch R. J.
Published: March 2003

Site preparation practices used during establishment of second rotation Pinus plantations on the coastal lowlands of south-east Queensland became more conservative during the 1990s. Traditionally, site preparation included stick raking of residue into windrows, followed by burning. Areas subject to periodic saturation were then cultivated to form continuous high mounds, while better drained sites were contour strip cultivated. These practices were replaced by retention of residue biomass on hillslopes. Similarly, intensive site disturbance was increasingly replaced by tillage of the immediate planting zone only and, as far as possible, avoidance of continuous furrows, major drainage structures, and high mounding works. In the study reported here, simulated rainfall and overland flows were used to assess the impacts of the earlier, less-conservative site preparation practices on hillslope soil loss, nutrient loss, and the potential for off-site nutrient movement.Where residue from clearfell harvesting of the first rotation was not removed, runoff, erosion, and nutrient loss were negligible. Harvesting tended to distribute residue widely across hillslopes, and, together with naturally occurring understorey biomass, it formed a largely continuous groundcover. Highest concentrations of sediment in overland flow were recorded for hillslopes in the newly stick-raked condition. Sediment concentrations in overland flows applied to properly designed and constructed high mounds were low, even for large flows simulating relatively long furrow lengths. However, sediment in rainfall-induced runoff from mounded areas was observed to be nutrient enriched, indicating potential for an off-site nutrient pollution risk, at least prior to establishment of grass cover along furrows. Nutrient enrichment was correlated with enrichment of finer size classes of sediment in runoff.The work reported in this paper vindicated the move away from traditional residue removal and site preparation practices to an approach based on residue retention, minimum site disturbance, and, wherever possible, spot rather than continuous mounding/cultivation.
Characterisation of iron nodules in a Ultisol of central Taiwan
Authors: Pai C. W. , Wang M. K. , Chiang H. C. , King H. B. , Hwong J.-L. , Hu H. T.
Published: March 2003

The chemical and physical properties, clay mineralogy, and 14C radiocarbon age of iron nodules found in a Ultisol located on a low elevation terrace of Taiwan were investigated. The results indicated that the amount and size of iron nodules increase with soil depth. Free iron contents in nodules were markedly higher than in the surrounding soil matrix. Feo/Fed ratio was low in all iron nodules, indicating that the predominant form of free iron was crystalline. Al-substituted goethite was found as the predominant oxide mineral and Al substitution ranged from 16 to 24% mole. Illite and hydroxy-interlayered vermiculite and kaolinite were the dominant clay minerals in the iron nodules. X-ray fluorescence (XRF) analysis of the iron nodules are composed primarily of Fe, Si, and Al, and minor amounts of Mn. Based on the similarity of clay mineralogical compositions and radiocarbon dating ages, it is suggested that the major driving force promoting the formation of iron nodules was in situ weathering of saprolite by the frequent wetting/drying cycles. We speculate that illuviated iron played only a minor role in their formation.
Subsoil nitrogen mineralisation and its potential to contribute to NH4 accumulation in a Vertosol
Authors: Page K. L. , Dalal R. C. , Menzies N. W. , Strong W. M.
Published: March 2003

High concentrations of NH4+ (up to 270 kg N/ha) have been observed in a Vertosol below 1 m depth in south-east Queensland. This study examined the possibility that mineralisation associated with the removal of native vegetation (Acacia harpophylla) for cropping was responsible for the production of NH4+. Particularly, the potential contribution of decomposing root material and/or dissolved organic nitrogen (DON) leached into the subsoil after clearing was investigated. The amount of N that was contained within native vegetation root material was determined from an area of native vegetation adjacent to the cleared site containing elevated NH4+ concentrations. In addition, the amount of NH4+ that could be mineralised in the native vegetation soil was determined by monitoring NH4+ concentrations over 360 days in intact cores, and by conducting waterlogged incubations. To determine the rate at which a source of DON leached into the subsoil would mineralise, soil was amended with glutamic acid at a rate of 250 mg N/kg and placed under waterlogged incubation. The possibility that the acidic pH of the subsoil, or the lack of a significant subsoil microbial population, was inhibiting mineralisation was also examined by increasing soil pH from 4.4 to 7.0, and inoculating the subsoil with surface soil microorganisms during waterlogged incubations. Low concentrations of N, approximately 90 kg N/ha between 1.2 and 3 m, were found in the native vegetation root material. In addition, no net N mineralisation was observed in either the extended incubation of intact cores or in the control samples of the waterlogged incubations. Net N mineralisation was also not detected when the subsoil was amended with a source of organic N. Results indicate that this lack of mineralisation is largely due to pH inhibition of the microbial population. It is concluded that the mineralisation of either in situ organic material, or DON transported to the subsoil during leaching events, is unlikely to have significantly contributed to the subsoil NH4 accumulation at the study site.
The effect of soil texture and roots on the stable carbon isotope composition of soil organic carbon
Authors: Bird M. , Kracht O. , Derrien D. , Zhou Y.
Published: March 2003

This study examines the distribution of soil organic carbon and carbon-isotopes with depth and among particle size fractions in 2 forest soil profiles of contrasting texture from Cape York Peninsula, Queensland, Australia. The profile on sand has a comparatively low inventory of carbon (557 mg/cm2 from 0–100 cm) and exhibits comparatively small variations in δ13C value. In contrast, the clay-rich profile has a much larger inventory of soil organic carbon (1725 mg/cm2 from 0–100 cm) and large variations in δ13C value occur both with depth in the profile and between different particle size fractions. The considerable differences in carbon inventories and δ13C values between the sites appear to be largely due to soil textural differences. In�the absence of fine minerals the trend in δ13C value with decreasing particle size is to similar or lower δ13C values, due to an increase in the relative abundance of low δ13C compounds in the residue left by microbial decomposition. In the presence of fine minerals, the trend is to higher δ13C values due to the stabilisation of the products of microbial decomposition by the fine minerals. Thus, the bulk δ13C value of soil organic carbon appears to be determined as much by the abundance of fine minerals in a soil profile as by isotope fractionation effects accompanying degradation. It is further postulated that an initial rapid rise in δ13C value in the upper soil layers is due to an increase in the relative importance of higher 13C, root-derived carbon immediately below the soil surface.
Interferences in the determination of isotopically exchangeable P in soils and a method to minimise them
Authors: Hamon R. E. , McLaughlin M. J.
Published: March 2003

In soils with a high phosphate buffering capacity or in soils with large amounts of colloidal P in soil solution, E-values often overestimate P availability. These problems have been ascribed to a variety of causes including analytical difficulties in terms of measuring low concentrations of P, colorimetric interferences, and inadvertent measurement of non-isotopically exchangeable colloidal P. We investigated measurement of E-values in 8 soil types, of which 6 had properties likely to give overestimates of size of the available pool of P based on results of previous authors. The potential for overestimation of the E-value due to interferences described above was identified in several soil types. A simple anion exchange resin purification step was introduced to the E-value methodology. The resin adsorbs both 31P and 32P isotopes in proportion to their concentration in the solution and minimises transfer of colloids and Si into the analysed eluant, thereby providing a simple way to increase the eluant P concentration and to avoid analytical interferences.
Use and abuse of isotopic exchange data in soil chemistry
Authors: Hamon R. E. , Bertrand I. , McLaughlin M. J.
Published: March 2003

Isotope dilution techniques have been widely applied in research investigating the fate and availability of different elements in soils. One technique, known as the 'E-value' method, involves tracking the depletion of isotope from solution in a soil suspension to determine the amount of isotopically exchangeable element at a given time following addition of isotope. An assumption underlying this method is that the isotope behaves exactly as the cold element in soil and hence, the amount of depletion of isotope from solution relative to the quantity of cold element at a given time can be used to determine specific elemental compartments in the soil. However, there has been some confusion in the literature with many studies neglecting to consider that an E-value can be composed of either a solid-phase compartment (Ee) or a combination of a solid-phase and solution compartment (Ea) depending on how it is calculated. Selection of the correct E-value formula is crucial for meaningful interpretation of data in soils with low buffering capacities, high concentrations of the element of interest in solution, or methods which use very short incubation times of isotope with soil. Here we discuss the derivation of E-value equations and circumstances where each should be applied.
Cadmium distribution and inventories at a pre-European seabird breeding site on agricultural land, Banks Peninsula, New Zealand
Authors: Hawke D. J.
Published: March 2003

Cadmium distribution was determined at a hill country agricultural site with no history of fertiliser application, but where pre-European seabird breeding occurred. Total Cd concentrations were measured in 2 depth profiles on the ridgeline, and in surface soil (0–15 cm; 15 ridgeline and 7 sideslope transects). Concentrations were low (range 0.04–0.13 mg/kg) for New Zealand agricultural soils. Concentrations were independent of stock camps (locations frequented by grazing animals), altitude, soil depth, organic matter, and N and P concentrations. Surface Cd concentrations on the sideslope were significantly higher than the ridgeline. Inventories from the 2 ridgeline profiles (29.9 ± 2.4 mg/m2; 18.4 ± 1.5 mg/m2) were higher than the 16 mg/m2 and 7 mg/m2, respectively, predicted from the loess and basalt parent material concentrations; surface soil concentrations also exceeded those predicted from parent materials. Together, these results suggest that agricultural activity has not significantly redistributed Cd, and that external sources have contributed a large proportion of soil Cd. Atmospheric input was too low to explain all of the observed enrichment. Instead, Cd distribution was consistent with seabird input concentrated in the deeper soils of the sideslope rather than the relatively thin soils of the ridgeline.
The effect of a gap between the access tube and the soil during neutron probe measurements
Authors: Li J. , Smith D. W. , Fityus S. G.
Published: March 2003

The neutron probe is a tool employed for the measurement of water content in a soil mass. The presence of a gap between the soil and the neutron probe access tube, filled with either air or water, inevitably introduces a systematic error in neutron probe readings. In this study, experimental investigations and numerical analyses were carried out to evaluate the effects of this gap on neutron probe calibration. The numerical model was developed based on the multigroup neutron diffusion equations and the finite element method. The experiments were conducted in a heavy clay soil. The results show that an air gap of 2.5–30 mm between the soil and a 50-mm-diameter aluminium tube could lead to an underestimation of soil water content by 5–45%, but significant underestimation was apparent for air gaps <10 mm. It is also found that the neutron count is significantly overestimated if the gap around the access tube is filled with water rather than air, but this effect is most significant for larger gaps. The results of this research clearly indicate that a gap between the neutron probe access tube and the soil profile should be avoided during field installation, and that if a gap between the access tube and soil develops during service, a systematic error will be introduced into measurements.
A model to predict lightning-caused fire occurrences
Authors: Anderson Kerry
Published: March 2003

This paper presents a model to predict the probability that a lightning flash will lead to a detectable fire. This is done by estimating the probability of the lightning flash having a long-continuing current, the probability of ignition, the probability of survival, and the probability of arrival. Individual probabilities are calculated using the lightning, noon weather, and forest inventory data and combined to predict the number of ignitions, holdovers, and detectable fires within a region. The model was run for six fire seasons in Saskatchewan and predicted results were compared with the actual number of fires for that season. The model successfully predicted the number of fires on 55.7% of the days with a 64.8% detection rate and a false alarm rate of 29.7%. The model was found to be highly sensitive to moisture conditions, resulting in some unusually high predictions under dry conditions.
Forecasting diurnal variations in fire intensity to enhance wildland firefighter safety
Authors: Beck J. A. , Alexander M. E. , Harvey S. D. , Beaver A. K.
Published: March 2003

The extent to which the concept of displaying the diurnal variation in Byram's fire intensity on a daily basis during the fire season has been applied in the Province of British Columbia, Canada, to ensure safe and productive wildland firefighting work practices is described. This has been made possible by using the Canadian Forest Fire Danger Rating System coupled with fire weather forecasts and local information on the state of the fire environment in regards to fuel types, fuel moisture conditions and slope steepness. The resulting operational fire management tool has been the development, beginning in the mid 1990s, of the British Columbia Fire Weather and Behavior Advisory and Warning System. Potential areas for improvement in this system are detailed.
The Oklahoma Fire Danger Model: An operational tool for mesoscale fire danger rating in Oklahoma
Authors: Carlson J. D. , Burgan Robert E. , Engle David M. , Greenfield Justin R.
Published: March 2003

This paper describes the Oklahoma Fire Danger Model, an operational fire danger rating system for the state of Oklahoma (USA) developed through joint efforts of Oklahoma State University, the University of Oklahoma, and the Fire Sciences Laboratory of the USDA Forest Service in Missoula, Montana. The model is an adaptation of the National Fire Danger Rating System (NFDRS) to Oklahoma, but more importantly, represents the first time anywhere that NFDRS has been implemented operationally using hourly weather data from a spatially dense automated weather station network (the Oklahoma Mesonet). Weekly AVHRR satellite imagery is also utilized for live fuel moisture and fuel load calculations. The result is a near-real-time mesoscale fire danger rating system to 1-km resolution whose output is readily available on the World Wide Web (http://agweather.mesonet.ou.edu/models/fire). Examples of output from 25 February 1998 are presented.The Oklahoma Fire Danger Model, in conjunction with other fire-related operational tools, has proven useful to the wildland fire management community in Oklahoma, for both wildfire anticipation and suppression and for prescribed fire activities. Instead of once-per-day NFDRS information at two to three sites, the fire manager now has statewide fire danger information available at 1-km resolution at up to hourly intervals, enabling a quicker response to changing fire weather conditions across the entire state.
A new method for the analysis of fire spread modeling errors
Authors: Fujioka Francis M.
Published: March 2003

Fire spread models have a long history, and their use will continue to grow as they evolve from a research tool to an operational tool. This paper describes a new method to analyse two-dimensional fire spread modeling errors, particularly to quantify the uncertainties of fire spread predictions. Measures of error are defined from the respective spread distances of the actual and simulated fires at specified points around their perimeters. A ratio error provides a correction factor for the spread model bias. The characteristics of the error are defined by a probability model, which is used to construct error bounds on fire spread predictions. The method is applied to the Bee Fire, which burned 3848 ha on the San Bernardino National Forest, California, in summer 1996. The study focused on the early, presuppression stages of the fire. A mesoscale spectral model was used to simulate weather conditions on a grid interval of 2 km. The FARSITE system was used to simulate fire growth during the first 105 min of the fire. The case study showed how difficult fire spread modeling is under the conditions presented by the Bee Fire.
Modification of the Fosberg fire weather index to include drought
Authors: Goodrick Scott L.
Published: March 2003

The Fosberg fire weather index is a simple tool for evaluating the potential influence of weather on a wildland fire based on temperature, relative humidity and wind speed. A modification to this index that includes the impact of precipitation is proposed. The Keetch-Byram drought index is used to formulate a ‘fuel availability’ factor that modifies the response of the fire weather index. Comparisons between the original and modified indices are made using historical fire data from the Florida Division of Forestry. The addition of the fuel availability factor helps increase the utility of the fire weather index as it offers an improved relationship between the index and area burned.
An examination of the sensitivity of numerically simulated wildfires to low-level atmospheric stability and moisture, and the consequences for the Haines Index
Authors: Jenkins Mary Ann
Published: March 2003

The Haines Index, an operational fire–weather index introduced in 1988 and based on the observed stability and moisture content of the near-surface atmosphere, has been a useful indicator of the potential for high-risk fires in low wind conditions and flat terrain.
The Haines Index is of limited use, however, as a predictor of actual fire behavior. To develop a fire–weather index to predict severe or erratic wildfire behavior, an understanding of how the ambient lower-level atmospheric stability and moisture affects the growth of a wildfire is needed. This study is a first step in this process. This study investigates, through four comparative numerical simulations with a coupled wildfire–atmosphere model, the sensitivity of wildland fires to atmospheric stability and moisture, and in the process explores the correspondence between atmospheric stability and moisture, wildfire behavior, and the Haines Index. In the first three fire simulations, the model atmosphere was initially set to identical moisture but different instability conditions that correspond to Haines Indexes for low, moderate, and high potential for severe fire development. In the fourth fire simulation, the initial atmospheric and moisture conditions were for a high-risk fire Haines Index rating, but different from the initial conditions of dryness and stability of the previous experiments. The study indicates that high-risk fire development is sensitive to near-surface atmospheric stability and moisture, and that there is a range of atmospheric stability and moisture conditions that is important to the development of severe or erratic fire behavior, and that this range is within the atmospheric stability and moisture conditions represented by a Haines Index for high potential for severe fire. The analyses also suggest that there is a substantial latitude of fire behavior for fires rated as this Index, indicating that this Index should be further divided, or refined.
Studying wildfire behavior using FIRETEC
Authors: Linn Rodman , Reisner Jon , Colman Jonah J. , Winterkamp Judith
Published: March 2003

A coupled atmospheric/wildfire behavior model is described that utilizes physics-based process models to represent wildfire behavior. Five simulations are presented, four of which are highly idealized situations that are meant to illustrate some of the dependencies of the model on environmental conditions. The fifth simulation consists of a fire burning in complex terrain with non-homogeneous vegetation and realistic meteorological conditions. The simulated fire behavior develops out of the coupling of a set of very complex processes and not from prescribed rules based on empirical data. This represents a new direction in wildfire modeling that we believe will eventually help decision makers and land managers do their jobs more effectively.
A dynamics based view of atmosphere - fire interactions
Authors: Potter Brian E.
Published: March 2003

Current research on severe fire interactions with the atmosphere focuses largely on examination of correlations between fire growth and various atmospheric properties, and on the development of indices based on these correlations. The author proposes that progress requires understanding the physics and atmospheric dynamics behind the correlations. A conceptual 3-stage model of fire development, based on atmospheric structure, is presented. Using parcel theory and basic atmospheric dynamics equations, the author proposes possible causal explanations for some of the known correlations. The atmospheric dynamics are discussed in terms of the 3-stage model, but can also be viewed more generally. The overall goal is to reframe fire–atmosphere interactions in a way that will allow better understanding and progress in fire science, prediction, and safety.
Long lead statistical forecasts of area burned in western U.S. wildfires by ecosystem province
Authors: Westerling Anthony L. , Gershunov Alexander , Cayan Daniel R. , Barnett Tim P.
Published: March 2003

A statistical forecast methodology exploits large-scale patterns in monthly U.S. Climatological Division Palmer Drought Severity Index (PDSI) values over a wide region and several seasons to predict area burned in western U.S. wildfires by ecosystem province a season in advance. The forecast model, which is based on canonical correlations, indicates that a few characteristic patterns determine predicted wildfire season area burned. Strong negative associations between anomalous soil moisture (inferred from PDSI) immediately prior to the fire season and area burned dominate in most higher elevation forested provinces, while strong positive associations between anomalous soil moisture a year prior to the fire season and area burned dominate in desert and shrub and grassland provinces. In much of the western U.S., above- and below-normal fire season forecasts were successful 57% of the time or better, as compared with a 33% skill for a random guess, and with a low probability of being surprised by a fire season at the opposite extreme of that forecast.
Measuring moisture dynamics to predict fire severity in longleaf pine forests
Authors: Ferguson Sue A. , Ruthford Julia E. , McKay Steven J. , Wright David , Wright Clint , Ottmar Roger
Published: March 2003

To understand the combustion limit of biomass fuels in a longleaf pine (Pinus palustris) forest, an experiment was conducted to monitor the moisture content of potentially flammable forest floor materials (litter and duff) at Eglin Air Force Base in the Florida Panhandle. While longleaf pine forests are fire dependent ecosystems, a long history of fire exclusion has allowed large amounts of pine litter and duff to accumulate. Reintroducing fire to remove excess fuel without killing the longleaf pine trees requires care to burn under litter and duff moisture conditions that alternately allow fire to carry while preventing root exposure or stem girdle. The study site was divided into four blocks that were burned under litter and duff moisture conditions of wet, moist, dry, and very dry. Throughout the 4-month experiment, portable weather stations continuously collected meteorological data, which included continuous measurements of water content in the forest floor material from in situ, time-domain reflectometers. In addition, volumetric moisture samples were collected almost weekly, and pre-burn fuel load and subsequent consumption were measured for each burn. Meteorological variables from the weather stations compared with trends in fuel moisture showed the influence of relative humidity and precipitation on the drying and wetting rates of the litter and duff. Fuel moisture conditions showed significant influence on patterns of fuel consumption and could lead to an understanding of processes that govern longleaf pine mortality.
Near-real time mapping of Keetch-Byram drought index in the south-eastern United States
Authors: Janis Michael J. , Johnson Michael B. , Forthun Gloria
Published: March 2003

High spatial resolution maps of daily Keetch-Byram Drought Index (KBDI) are constructed for the south-eastern United States. KBDI is a cumulative algorithm for estimating fire potential from meteorological information, including daily maximum temperature, daily total precipitation, and mean annual precipitation. With few input parameters, the KBDI is attractive for providing estimates of fire potential at a large number of locations. The Southeast Regional Climate Center (SERCC) applies the original algorithms over daily time steps to maximize the response time in the event of rapidly increasing fire potential. Algorithms are applied to a network of 261 weather stations across the south-eastern United States to provide regional contour maps of KBDI as well as maps of week-to-week KBDI difference. Though uniformity and spatial density of weather stations and the consistency of input parameters are potential hurdles, it is shown that careful compilation of meteorological databases makes KBDI a tractable and valuable monitoring tool for automated fire-potential monitoring.
The diets of cats, foxes and dingoes in relation to prey availability in the Tanami Desert, Northern Territory
Authors: Paltridge Rachel
Published: March 2003

In most areas of Australia, mammals constitute the staple diets of cats, foxes and dingoes. In central Australia the abundance of mammals is often too low to meet the dietary requirements of these carnivores and yet populations of cats, foxes and dingoes persist. To investigate alternative feeding strategies of cats, foxes and dingoes in arid environments, their diets were monitored in relation to prey availability in two areas of the Tanami Desert where rabbits do not occur. Dietary information was obtained by analysing predator scats collected between 1995 and 1997. Prey availability was monitored by track counts, pitfall trapping, Elliott trapping, and bird counts along walked transects. In contrast to dietary studies elsewhere in Australia, it was found that reptiles were an important component of the diets of predators in the Tanami Desert, and should be classified as seasonal staples. Birds increased in importance in the diets of cats and foxes during the winter, when reptiles were less active. There was considerable overlap between the diets of all three predators, although dingoes ate more large prey items (e.g.�macropods) than the other two predators. Results highlight the opportunistic feeding habits of cats, foxes and dingoes and show that, although mammalian prey are less important in central Australia than has been found elsewhere, species that are vulnerable to extinction, such as the bilby (Macrotis lagotis), mulgara (Dasycercus cristicauda) and marsupial mole (Notoryctes typhlops), are also consumed by these predators.
Improved sampling of wildlife populations using airborne surveys
Authors: Khaemba W. M. , Stein A.
Published: March 2003

Parameter estimates, obtained from airborne surveys of wildlife populations, often have large bias and large standard errors. Sampling error is one of the major causes of this imprecision and the occurrence of many animals in herds violates the common assumptions in traditional sampling designs like systematic or simple random sampling even when stratification is used. In this paper, we present an adaptive sampling design that uses criteria of observed animal counts to maximise sample information and that is independent of the usual assumption of a uniform distribution for wildlife populations. For illustration, the design is applied to data derived from a survey carried out in the Masai Mara ecosystem (Mara) of Kenya, with a focus on three species: elephant (Loxodonta africana), kongoni (Alcelaphus buselaphus) and wildebeest (Connochaetes taurinus). The sampling design's more efficient estimates show an improvement on those from conventional systematic design, with a greater than 10 times reduction in estimated bias and a 37% lowering of the standard error. The adaptive design, however, underestimates population totals for species in large herds, while a multivariate extension gives only marginal improvements.
Rapid evaluation of pasture quality for a critically endangered mammal, the northern hairy-nosed wombat (Lasiorhinus krefftii)
Authors: Woolnough Andrew P. , Foley William J.
Published: March 2003

Near-infrared spectroscopy (NIRS) was used to predict the nutritive value of
forage species available to the critically endangered northern hairy-nosed
wombat (Lasiorhinus krefftii). Nutritive attributes of
the forage successfully estimated included total nitrogen concentration, fibre
(including neutral detergent fibre, acid detergent fibre and acid lignin),
organic matter, water soluble carbohydrates and in vitro
dry matter digestibility. The reported results demonstrate the seasonal
variability of the forage resource available to
L. krefftii in its tropical savanna habitat.
Multivariate modelling of the spectra enabled the nutritive value of forage
samples to be estimated with coefficients of determination
(r2) of 0.770–0.995 and
standard errors of the cross-validation of 0.070–2.850 using a modified
partial least-squares analysis technique. The standard error of the laboratory
was 0.02–1.42. This study demonstrates that broad-based NIRS predictive
equations can be used to predict the nutritive value of a number of plant
types available to a herbivore over time. By using NIRS the analyst can
rapidly analyse large numbers of samples with limited reduction of precision,
thereby enabling large-scale ecological applications that may have previously
been impeded by time and costs.
Factors influencing annual variation in breeding by common brushtail possums (Trichosurus vulpecula) in New Zealand
Authors: Ramsey Dave , Efford Murray , Cowan Phil , Coleman Jim
Published: March 2003

We assembled data on annual variation in breeding rates of brushtail possums
from four long-term studies in the lower North Island of New Zealand, three of
which spanned more than 20 years. In each study, more than 80% of adult
females bred in most years. The major exception was in 1996, when breeding
failed synchronously at sites separated by up to 122 km. The overall breeding
rate in 1996 at these sites was 28% (n =
201). Other instances of low breeding rate (<70%) occurred
asynchronously at particular sites. We analysed variation in breeding rates to
determine the contributions to annual variation of individual condition (body
weight), population density, food resources and other environmental
predictors. The probability of breeding declined rapidly as body condition
fell below average. An index of fruitfall of hinau
(Elaeocarpus dentatus), a highly nutritious food used by
possums, and population density in the previous year were the most important
predictors of possum condition and breeding rate. High density in the previous
year coupled with low hinau fruitfall in the current year predicted
below-average body condition and reduced breeding rate. Although the magnitude
of these effects were only significant in ‘extreme’ years, they
are consistant with delayed density-dependent effects on fecundity in
brushtail possums.
Low-density koala (Phascolarctos cinereus) populations in the mulgalands of south-west Queensland. I. Faecal pellet sampling protocol
Authors: Sullivan B. J. , Baxter G. S. , Lisle A. T.
Published: March 2003

Koala (Phascolarctos cinereus) populations in eastern Australia are threatened by land clearing for agricultural and urban development. At the same time, conservation efforts are hindered by a dearth of information about inland populations. Faecal deposits offer a source of information that is readily available and easily collected non-invasively. We detail a faecal pellet sampling protocol that was developed for use in a large rangeland biogeographic region. The method samples trees in belt transects, uses a thorough search at the tree base to quickly identify trees with koala pellets under them, then estimates the abundance of faecal pellets under those trees using 1-m2 quadrats. There was a strong linear relationship between these estimates and a complete enumeration of pellet abundance under the same trees. We evaluated the accuracy of our method in detecting trees where pellets were present by means of a misclassification index that was weighed more heavily for missed trees that had high numbers of pellets under them. This showed acceptable accuracy in all landforms except riverine, where some trees with large numbers of pellets were missed. Here, accuracy in detecting pellet presence was improved by sampling with quadrats, rather than basal searches. Finally, we developed a method to reliably age pellets and demonstrate how this protocol could be used with the faecal-standing-crop method to derive a regional estimate of absolute koala abundance.
Tree use, diet and home range of the koala (Phascolarctos cinereus) at Blair Athol, central Queensland
Authors: Ellis W. A. H. , Melzer A. , Carrick F. N. , Hasegawa M.
Published: March 2003

Free-ranging koalas (Phascolarctos cinereus) were monitored by means of radio-relocation in the area of Blair Athol Coal Mine and surrounding properties. Daytime tree use, home range and diet of these koalas was determined in spring and autumn, as was the leaf moisture composition of potential fodder species. Koalas used on average 93 (male koalas) and 56 (female koalas) trees during the period of observation, occupying home ranges of 135 and 101 ha respectively. Mean sightings per tree were 1.19 for both males and females and home-range sizes were not significantly different between sexes or seasons. Koalas were observed returning to previously used daytime roosting trees infrequently (<12%). Although koalas were observed roosting in trees of the species that they ate, proportional species representation in the diet of these koalas during spring and autumn did not accurately reflect concurrent observations of their daytime tree-roosting behaviour. Koalas were observed to utilise non-fodder species for daytime roosting, and patterns of daytime tree use and diet selection varied between individuals inhabiting adjacent communities within the site. Leaf moisture of tree species represented in koala diets was greater in autumn than spring.
Estimated 1080 dose rate for the M-44 ejector for the control of red foxes (Vulpes vulpes)
Authors: Marks C. A. , Gigliotti F. , Busana F.
Published: March 2003

Recent studies have suggested that bait movement and caching by foxes (Vulpes vulpes) may increase the potential risk of off-target effects from 1080 meat baits close to urban habitats. The M-44 ejector is an alternative way to deliver 1080 to foxes that will eliminate bait movement and caching. Whilst the M-44 ejector has been used for the control of foxes using cyanide in the United States, we investigated its use with 1080 as a toxicant. Exotic eutherian carnivores are generally more sensitive to 1080 than are most Australian endemic wildlife species, yet no useful difference in sensitivity to cyanide exists for these groups. The lower risk associated with occupational exposure to 1080 compared with cyanide suggests that it is a more desirable toxicant for fox control. Pen trials were undertaken in order to establish an appropriate capsule dose of 1080 to be used in the ejector. A minimum capsule dose of 2.7 mg of 1080 is estimated to be consistently lethal to foxes weighing up to 8.3 kg. The recommended dose is below the current meat bait dose of 3.0 mg 1080 used in Victoria. This may represent an improvement in occupational safety and a reduction in non-target risk.
Sensitivity to sodium fluoroacetate (1080) of native animals from north-western Australia
Authors: Martin Gary R. , Twigg Laurie E.
Published: March 2003

The sensitivity to sodium monofluoroacetate (1080) of 9 species of native
animals from north-western Australia was assessed using the increasing dose
procedure to determine the Approximate Lethal Dose for each species.
Granivorous birds from this region (e.g. ducks, corellas) were generally more
sensitive to 1080 than their counterparts from southern Australia, and would
be theoretically at risk from primary poisoning during 1080 grainbased baiting
programs. However, the tolerance to 1080 of birds of prey from these areas is
sufficient that these species face little risk of secondary poisoning during
pest-control programs aimed at rodents or rabbits. The risk of primary
poisoning to raptors from meat baits containing 6 mg 1080 per bait or less
also appears to be low. The coexistence of brown falcons and barn owls with
fluoroacetate-bearing vegetation over parts of their range has probably
contributed to their development of tolerance to fluoroacetate.
Aggressive interactions between freshwater turtle, Chelodina oblonga, hatchlings and freshwater crayfish, Cherax spp.: implications for the conservation of the critically endangered western swamp turtle, Pseudemydura umbrina
Authors: Bradsell P. , Prince J. , Kuchling G. , Knott B.
Published: March 2003

Interactions between turtle hatchlings of Chelodina oblonga and the marron, Cherax tenuimanus, the gilgie, C. quinquecarinatus, the koonac, C. preissii (freshwater crayfish native to Western Australia) and the introduced yabby, Cherax. sp., were observed in laboratory-based trials in uncluttered aquaria.
Marron, koonacs and yabbies, but not gilgies, showed aggressive and predatory behaviour towards the hatchlings. In total, 59 attacks were observed in 26 of the 80 trials. On 12 occasions, crayfish captured hatchlings in their chelae. On two occasions, the attack of the crayfish was so quick that the hatchling was killed instantly. Compared with movement when alone, movement of hatchlings was significantly greater in the presence of koonacs and yabbies, but significantly less in the presence of marron and gilgies.
The range of non-native yabbies currently is expanding into Ellen Brook Nature Reserve which harbours the last naturally persisting population of the critically endangered western swamp turtle, Pseudemydura umbrina. No native crayfish occur in the habitat of P. umbrina in this reserve. The possible invasion by the ecological generalist yabby poses a new threat to the survival of P. umbrina.