Andrew P. Woolnough

Ecological applications of near infrared reflectance spectroscopy - a tool for rapid, cost-effective prediction of the composition of plant and animal tissues and aspects of animal performance

Abstract Many ecological studies rely heavily on chemical analysis of plant and animal tissues. Often, there is limited time and money to perform all the required analyses and this can result in less than ideal sampling schemes and poor levels of replication. Near infrared reflectance spectroscopy (NIRS) can relieve these constraints because it can provide quick, non-destructive and quantitative analyses of an enormous range of organic constituents of plant and animal tissues. Near infrared spectra depend on the number and type of CH, NH and OH bonds in the material being analyzed. The spectral features are then combined with reliable compositional or functional analyses of the material in a predictive statistical model. This model is then used to predict the composition of new or unknown samples. NIRS can be used to analyze some specific elements (indirectly – e.g., N as protein) or well-defined compounds (e.g., starch) or more complex, poorly defined attributes of substances (e.g., fiber, animal food intake) have also been successfully modeled with NIRS technology. The accuracy and precision of the reference values for the calibration data set in part determines the quality of the predictions made by NIRS. However, NIRS analyses are often more precise than standard laboratory assays. The use of NIRS is not restricted to the simple determination of quantities of known compounds, but can also be used to discriminate between complex mixtures and to identify important compounds affecting attributes of interest. Near infrared reflectance spectroscopy is widely accepted for compositional and functional analyses in agriculture and manufacturing but its utility has not yet been recognized by the majority of ecologists conducting similar analyses. This paper aims to stimulate interest in NIRS and to illustrate some of the enormous variety of uses to which it can be put. We emphasize that care must be taken in the calibration stage to prevent propagation of poor analytical work through NIRS, but, used properly, NIRS offers ecologists enormous analytical power.

Invasive species can't cover their tracks : using microsatellites to assist management of starling (Sturnus vulgaris) populations in Western Australia

Invasive species are known to cause environmental and economic damage, requiring management by control agencies worldwide. These species often become well established in new environments long before their detection, resulting in a lack of knowledge regarding their history and dynamics. When new invasions are discovered, information regarding the source and pathway of the invasion, and the degree of connectivity with other populations can greatly benefit management strategies. Here we use invasive common starling (Sturnus vulgaris) populations from Australia to demonstrate that genetic techniques can provide this information to aid management, even when applied to highly vagile species over continental scales. Analysis of data from 11 microsatellites in 662 individuals sampled at 17 localities across their introduced range in Australia revealed four populations. One population consisted of all sampling sites from the expansion front in Western Australia, where control efforts are focused. Despite evidence of genetic exchange over both contemporary and historical timescales, gene flow is low between this population and all three more easterly populations. This suggests that localized control of starlings on the expansion front may be an achievable goal and the long‐standing practice of targeting select proximal eastern source populations may be ineffective on its own. However, even with low levels of gene flow, successful control of starlings on the expansion front will require vigilance, and genetic monitoring of this population can provide essential information to managers. The techniques used here are broadly applicable to invasive populations worldwide.

Population genetic tools for pest management: a review.

Population genetic tools have the potential to answer key questions in pest management including quantifying the number of genetically distinct populations represented in an invasion, the number of individuals present, whether populations are expanding or contracting, identifying the origin of invasive individuals, the number of separate introduction events that have occurred and in which order, and the rate that individuals are moving between populations. Genetic methods have only recently gained sufficient resolution to address these questions due to advances in laboratory techniques coupled with an increase in computational power. In combination, these methods may lead to a more comprehensive understanding of the dynamics of invasions. The expansion of the European starling (Sturnus vulgaris) into Western Australia is used as an applied example of how genetic methods can be integrated to provide vital information to improve pest-management strategies. Invasion events also may provide a unique opportunity to test some of these methodologies.

Mitochondrial DNA offers unique insights into invasion history of the common starling.

Mitochondrial DNA (mtDNA) can be a powerful genetic marker for tracing origins and history of invasive populations. Here, we use mtDNA to address questions relevant to the understanding of invasion pathways of common starlings (Sturnus vulgaris) into Western Australia (WA) and discuss the utility of this marker to provide information useful to invasive species management. Mitochondrial sequence data indicate two geographically restricted genetic groups within Australia. Evidence of dispersal from genetically distinct sources outside the sampled range of starlings in Australia suggests increased vigilance by management agencies may be required to prevent further incursions from widely separated localities. Overall, genetic diversity in Australia was lower than in samples from the native range. Within Australia, genetic diversity was lowest in the most recently colonized area in the west, indicating that demographic bottlenecks have occurred in this area. Evidence of restricted dispersal between localities on the edge of the range expansion (ERE) in WA and other Australian sampling localities suggests that localized control within the ERE may be effective in preventing further range expansion. Signatures of spatial and demographic expansion are present in mismatch analyses from sampling localities located at the ERE, but neutrality indices did not support this finding, suggesting that the former may be more sensitive to recent expansion. Additionally, mismatch analyses support the presence of admixture, which is likely to have occurred pre‐introduction. We compare our findings with those from a microsatellite study of the same samples and discuss how the mtDNA analyses used here offer valuable and unique insights into the invasion history of introduced species.

Comparison of three techniques for the attachment of radio transmitters to European Starlings

Abstract A captive study was conducted to determine the most appropriate method for attaching radio transmitters to a medium-sized (20–100 g) passerine, the European Starling (Sturnus vulgaris). Using mock transmitters, three methods of attachment were tried: a body harness, a glued backpack, and a tail-mount. The harness was the most reliable in terms of duration of attachment, with six of eight attachments (75%) retained by the birds at the completion of the 24-d trial. In contrast, just two of eight (25%) glued backpack attachments remained in place at the conclusion of the study. Tail-mounts performed only slightly better than glued backpacks, with only three of eight tail-mounts remaining in place at the conclusion of the study. Flight, feeding, and perching activities were not affected by the attachments; however, some birds showed initial annoyance toward the mock radio transmitters, inferred by pecking directed at the attachment site. Each attachment method was found to slightly alter the activity (pecking) of the starlings compared to the control group, but this persisted only for the first day following attachment. On the basis of the pecking response, tail-mount attachments were the least aggravating to the birds followed by the harness method. Once adjusted to the attachment, we observed no difference in starling activity, and the body condition of control and treated birds remained similar for the duration of the trials. We recommend the use of the harness for attaching radio transmitters to European Starlings and other similar sized passerines, particularly if birds are expected to molt during the experimental period.

Feral pigs: predicting future distributions

Feral pig populations are expanding in many regions of the world following historically recent introductions. Populations are controlled to reduce damage to agriculture and the environment, and are also a recreational hunting resource. Knowledge of the area over which feral pigs may expand in the future could be used regionally to assist biosecurity planning, control efforts and the protection of biodiversity assets. The present study sought to estimate the future distribution of a recently introduced, expanding feral pig population in the remote Kimberley region of north-western Australia. An existing survey of feral pig distributions was enhanced and remote-sensing and weather data, reflecting or correlated with factors that may affect feral pig distributions, were collated and analysed. Relationships between feral pig distributions and these data were identified by using a generalised additive modelling approach. By the use of the model, the distribution of favourable habitat was estimated across the study region (89 125 km2). The potential future distribution of feral pigs in the Kimberley was then estimated, assuming only natural dispersal of feral pigs from areas of known feral pig status (cf. hunter-assisted movements or escape of domestic pigs). The modelling suggests that feral pigs could expand their distribution by realistic natural dispersal in the future (to 61 950 km2). This expansion possibility contains several strategically important areas (such as sea ports and biologically significant wetlands). This approach has the potential to improve biosecurity planning for the containment of the feral pig in the Kimberley and may have utility for other recently introduced invasive species in other regions. These results may also be used to improve pest-management programmes and contingency planning for exotic-disease incursions.

Assessment of the potential for competition between two sympatric herbivores - the northern hairy-nosed wombat, Lasiorhinus krefftii, and the eastern grey kangaroo, Macropus giganteus

The northern hairy-nosed wombat, Lasiorhinus krefftii, is a critically endangered grazing herbivore, restricted to a single population of just 65 individuals in the savanna of central Queensland. Lasiorhinus krefftii shares its habitat with another grazing herbivore of similar body size, the eastern grey kangaroo, Macropus giganteus. This study investigated the potential for M. giganteus to compete with L. krefftii for food. Analysis of faecal residues demonstrated that both herbivores consumed grass almost exclusively, with the exception of small quantities of sedges and dicotyledons. Dietary overlap between M. giganteus and L. krefftii was high, both in the consumption of plant species (90%) and plant parts (99%), suggesting that there is potential for dietary competition. Using the distribution of faecal deposits for both herbivores, analysis of habitat usage by multiple linear regression techniques indicated that M. giganteus exhibits clear associations with some habitat features but proved inconclusive for L. krefftii because of their use of defecation in social marking. However, an examination of the population dynamics of M. giganteus suggested that the densities reported in this study, although highly seasonal, are sufficiently low that competition with L. krefftii for food is currently negligible.

Rapid evaluation of pasture quality for a critically endangered mammal, the northern hairy-nosed wombat (Lasiorhinus krefftii)

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 (r 2 ) 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. Ra s e gr y ws A.and . F W o .

Selection on Mitochondrial Variants Occurs between and within Individuals in an Expanding Invasion

Mitochondria are critical for life, yet their underlying evolutionary biology is poorly understood. In particular, little is known about interaction between two levels of evolution: between individuals and within individuals (competition between cells, mitochondria or mitochondrial DNA molecules). Rapid evolution is suspected to occur frequently in mitochondrial DNA, whose maternal inheritance predisposes advantageous mutations to sweep rapidly though populations. Rapid evolution is also predicted in response to changed selection regimes after species invasion or removal of pathogens or competitors. Here, using empirical and simulated data from a model invasive bird species, we provide the first demonstration of rapid selection on the mitochondrial genome within individuals in the wild. Further, we show differences in mitochondrial DNA copy number associated with competing genetic variants, which may provide a mechanism for selection. We provide evidence for three rarely documented phenomena: selection associated with mitochondrial DNA abundance, selection on the mitochondrial control region, and contemporary selection during invasion.

Can the Judas technique be applied to pest birds

The Judas technique was evaluated for its use as a technique to assist with the control of the common starling (Sturnus vulgaris). This technique uses the natural behaviour of a gregarious animal to betray the location of itself and its companions through radio-telemetry. Two trials were conducted to assess and develop the technique for starlings. The first trial was conducted near the western edge of the starling’s current established range in Australia, at Penong in South Australia. Nine out of ten radio-tagged birds were successfully tracked from the ground and air. Estimates of the areas utilised varied from 1.1 km2 to 96.5 km2 (100% convex polygons). Night-time roosts were found for three of the nine radio-tagged birds and control (shooting) recovered just one bird directly associated with a Judas starling, as well as the radio-tagged bird. The second trial was conducted at Munglinup near Esperance in Western Australia. Munglinup is the site of a recent infestation of starlings and is the most western-known outlier of this pest in Australia. At this site, five radio-tagged starlings tracked from the ground and air, utilised areas ranging from 0.7 km2 to 51.6 km2. Reduced fidelity to roosting trees impaired our ability to destroy starlings here. However, the real value of the Munglinup trial was to expand the geographical area known to be occupied by this population from 103 km2 to more than 225 km2 and to identify habitats and roost sites used by the starlings. We conclude that the Judas technique could be applied to starlings and other pest birds with similar social structures as a means of strategic surveillance rather than as an adjunct to control per se.