Comparison of image and rapid field assessments of riparian zone condition in Australian tropical savannas

Suitable methods for measuring and monitoring the condition of riparian environments are being investigated by government agencies responsible for maintaining these environments in Australia. The objective of this work was to compare two riparian condition assessment approaches, the Tropical Rapid Appraisal of Riparian Condition (TRARC) method developed for rapid on-ground assessment of the environmental condition of savanna riparian zones and an image based riparian condition monitoring scheme. Measurements derived from these two approaches were compared and correlated. The sample representativeness of the TRARC method was evaluated and the cost-effectiveness and suitability for multi-temporal analysis of the two approaches were assessed. Two high spatial resolution multi-spectral QuickBird satellite images captured in 2004 and 2005 and coincident field data covering sections of the Daly River in the Northern Territory, Australia were used in this work. Both field and image data were processed to map indicators of riparian zone condition including percentage canopy cover, organic litter on the ground, canopy continuity, tree clearing, bank stability, and flood damage. Spectral vegetation indices, image segmentation, and supervised classification were used to produce riparian health indicator maps. QuickBird image data were used to examine if the spatial distribution of TRARC transects provided a representative sample of ground based estimates of riparian health indicators. Covering approximately 3% of the study area, the sample mean of the TRARC estimates of individual indicators of riparian zone condition were in most cases within 20% of the global mean derived from the whole imaged riparian area. The cost-effectiveness of the image based approach was compared to that of the ground based TRARC method. Results showed that the TRARC method was more cost-effective at spatial scales from 1 km to 200 km of river in relatively homogeneous riparian zones along rivers with only one channel, while image based assessment becomes more feasible at regional scales (200–2000 km of river). A change detection analysis demonstrated that image data can provide detailed information on gradual change, while the TRARC method is less suited for multi-temporal analysis due to the ranked data format, which inhibits precise detection of change. However, results from both methods were considered to complement each other for single date assessment of riparian zones if used at appropriate spatial scales.     

Scrub-itch mite infestation in the endangered bridled nailtail wallaby

Skin lesions on the ears and inguinal and axillary regions of a number of adult animals within a captive population of the endangered bridled nailtail wallaby ( Onychogalea fraenata ) were associated with the trombiculid mite, Eutrombicula hirsti . The local inflammatory response of these Australian marsupials is described.     

Factors influencing the occurrence of fall armyworm parasitoids in Zambia

Journal of Pest Science - Invasive alien species have environmental, economic and social impacts, disproportionally threatening livelihood and food security of smallholder farmers in low- and...     

Use and misuse of multiple comparisons in animal experiments.

The objective of many animal experiments is to detect meaningful relationships among treatments and associated responses. Types of comparisons of means include pairwise multiple comparisons, planned orthogonal or nonorthogonal contrasts, and orthogonal polynomials. Some procedures are appropriate only for specific types of treatment designs and specific types of objectives. Pairwise, multiple comparisons are appropriate only for comparing unstructured, qualitative treatments. Planned comparisons partition the overall set of treatment effects into independent or nonindependent subsets, with special application to factorials. Orthogonal polynomial (regression) procedures assess relationships between quantitative treatments and response when a full range of responses or an optimal dose is of interest. Recommendations for appropriate use of each mean comparison procedure are illustrated using data from three Journal of Animal Science articles. Also mentioned are a number of computer graphics packages that provide creative ways to display biological relationships and can be linked to statistical packages for input and to word processors or 35-mm cameras for output.     

Validation of a new dental plaque quantification method in dogs

Current methods for the quantification of plaque accumulation in cats and dogs are well-accepted adaptations of traditional human models, but have required substantial modifications in order to compensate for the inherent differences in compliance, cooperation, and temperament between animals and humans. While these modifications have sought to maintain or improve upon the accuracy and reproducibility of the original methods, they also have increased the complexity of the technique and have required additional scorer time and animal cooperation, which leads to increased cost of trials. Therefore, research was directed toward the development and validation of a new substrate scoring system that reduces resources while maintaining or increasing the reproducibility attributed to the more traditional methods. This new gingival contour plaque index was shown to be accurate and reproducible, but used fewer animals, required less time, and eliminated the need for many of the specialized procedures required by traditional methods.     

Induced non-enzymatic browning of soybean meal. I. Effects of factors controlling non-enzymatic browning on in vitro ammonia release

Non-enzymatic browning was tested as a means of suppressing degradation of soybean meal (SBM) by ruminal microbes in five trials with in vitro ammonia release as the response criterion. Treatments imposed on SBM included reducing sugar source (xylose, glucose, fructose and lactose), reducing sugar level (1, 3 and 5 mol/mol SBM-lysine), pH (6.5, 8.5 and 10.0), dry matter (DM) content (65, 70, 75, 80, 85 and 90%) and varying lengths of heating time (0 to 90 min) at 150 C. Samples heated under conditions that promoted non-enzymatic browning gave greater (P less than .01) ammonia release suppression that when SBM was heated without these treatments. Xylose was the most reactive sugar, but extended heating of SBM containing glucose, fructose or lactose resulted in ammonia release similar to xylose. Increasing sugar level from 1 to 5 mol/mol SBM-lysine caused linear decreases (P less than .01) in ammonia release for xylose, glucose and fructose, but not lactose. Ammonia release was higher (P less than .01) at pH 6.5 than pH 8.5 and 10.0, and higher (P less than .01) at pH 9.5 than pH 10.0. Rate of non-enzymatic browning decreased when samples containing greater than 80% DM were heated. These results are interpreted to show that controlled non-enzymatic browning may be effective for reducing ruminal degradation of SBM.     

Enhancement of phagocytosis and bacterial killing by heterophils from neonatal chicks after administration of Salmonella enteritidis-immune lymphokines

During the first week post-hatch, chickens demonstrate an increased susceptibility to infection by bacteria such as Salmonella. The purpose of the present study was to evaluate the effects of immune lymphokines on phagocytosis and killing activities of heterophils in chicks during the first 1-7 days of life. Lymphokines isolated from chicken splenic T-cells harvested from Salmonella enteriditis (SE)-hyperimmunized hens (SE-ILK), have in past experiments, demonstrated augmentation of heterophil activity in day-of-hatch chicks resulting in protection from SE organ invasion. The present experiments reveal significant increases (p<0.05) in heterophil phagocytosis and killing when comparing chicks treated with SE-ILK to control groups in vitro. In SE-ILK-treated groups, a two-fold or greater increase is noted in heterophil phagocytosis within I h of incubation as compared to controls. Heterophils isolated from 1-day-old and 4-day-old chicks treated with SE-ILK killed significantly greater numbers (p<0.05) of SE than heterophils isolated from control groups. By Day 7 post-hatch, significance is not noted in the killing activity of heterophils from treated groups when compared to control groups. However, heterophils from SE-ILK groups continue to kill greater numbers of SE than control groups. These data support SE-ILK augmentation results in an enhanced heterophil function in chicks during the greatest period of susceptibility to Salmonella invasion.     

Rapid impact of Impatiens glandulifera control on above‐ and belowground invertebrate communities

The annual plant Impatiens glandulifera (Himalayan balsam) is the most widespread invasive non‐native weed in the British Isles. Manual control is widely used, but is costly and laborious. Recently, biological control using the rust fungus Puccinia komarovii var. glanduliferae has been trialled. We designed an experiment to assess the impact of these control methods on invertebrate communities in relation to unmanaged and uninvaded habitats, and to determine whether mycorrhizal inoculation aided post‐control recovery of these communities. Sixty invaded and twenty uninvaded field soil blocks were transplanted to the experiment site, where a mycorrhizal inoculum was added to half of all blocks. Biological and mechanical control treatments were applied to twenty invaded blocks independently; the twenty remaining invaded blocks were left intact. Above‐ and belowground invertebrate samples were collected from the blocks at the end of the growing season. Overall, aboveground invertebrate abundance increased with the removal of I. glandulifera, and several groups showed signs of recovery within one growing season. The effect of mechanical control was more variable in belowground invertebrates. Biological control did not affect aboveground invertebrate abundance but resulted in large increases in populations of belowground Collembola. Our experiment demonstrates that mechanical removal of I. glandulifera can cause rapid increases in invertebrate abundance and that its biological control with P. komarovii var. glanduliferae also has the potential to benefit native invertebrate communities.