Ecology and conservation of grassy wetlands dominated by spiny mud grass Pseudoraphis spinescens in the southern Murray–Darling Basin,Australia

相似文献   

Evaluation of Four Commercial Grower Diets for Production of Largemouth Bass

We compared performance (growth, survival, condition, and health indices) of largemouth bass, Micropterus salmoides, fingerlings (10.3 g [SE ± 0.5 g] and 92 mm [SE ± 1 mm] total length) fed one of four commercial grower feeds: Purina Aquamax Grower 400 (PAG; PMI Nutrition International LLC), Bio-Oregon BioDiet Grower (BDG; Bio-Oregon), Silver Cup Steelhead (SCS; Silver Cup), and Richloam Bass Fry Diet 12 (RBF; Silver Cup). Sixteen 833-L circular tanks, connected in parallel to a recirculation system, were initially stocked with 2.25 kg of fish (219 fish each, 0.32 fish/L) with four replicates per feed treatment. Water temperature was 25°C, and photoperiod was 15 h light:9 h dark. Feed sizes (2.4–3.0 mm) were comparable, and protein compositions ranged from 49% to 61%. Fish were fed to satiation multiple times per day (trial duration = 100 days). Overall, performance was best for fish fed RBF, followed by PAG and BDG, and then SCS. The SCS feed resulted in significantly lower growth and survival (P ≤ 0.05). The PAG and BDG feeds resulted in significantly lower growth than the RBF feed (P ≤ 0.05); however, survival did not differ (P > 0.05). Performance measures were positively correlated with protein, and protein to energy ratio and negatively correlated with fat and carbohydrate compositions. The four commercial grower feeds resulted in highly varied growth, survival, and health indices, and this research should facilitate feed choice for various largemouth bass production strategies as well as increase contribution of stocked fish.     

A preliminary in vivo study on the potential application of e-tracking in poultry using ink printed 2D barcodes

A preliminary study on the potential application of electronic tracking in poultry in vivo has been conducted. The experimental procedure for this study was based on previous in vitro findings (Fröschle et al., 2009) as part of the same research programme. The study consisted of two phases whereby an initial experiment using inkjet printing of 10 × 10 DataMatrix barcodes onto the beaks of broiler chickens in a live commercial setting has been carried out. Results demonstrated very poor percentage of readability after a short period of time. Barcodes deteriorated very rapidly and this was attributed to the physical effects on the barcodes of the actions of the chickens in a commercial environment, together with the inability of the ink to bond to the hard keratinous surface of the beak. In a subsequent part of the study, a number of commercially available ink types were screened, using a predetermined abrasion testing procedure, for their ability to bond to the beak and provide a readable barcode on the beaks following some predetermined graduated physical abrasion.     

Testing woody fuel consumption models for application in Australian southern eucalypt forest fires

Five models for the consumption of coarse woody debris or woody fuels with a diameter larger than 0.6 cm were assessed for application in Australian southern eucalypt forest fires including: CONSUME models for (1) activity fuels, (2) natural western woody and (3) natural southern woody fuels, (4) the BURNUP model and (5) the recommendation by the Australian National Carbon Accounting System which assumes 50% woody fuel consumption. These models were assessed using field data collected as part of the woody fuel consumption project (WFCP) in south-west Western Australia and northern-central Victoria. Three additional datasets were also sourced to increase variability in forest type, fuel complex and fire characteristics. These datasets comprised data from south-west Western Australia collected as part of Project Aquarius, the Warra Long Term Ecological Research site in Tasmania and Tumbarumba in south-eastern New South Wales. Combined the dataset represents a range of fire behaviour characteristic of prescribed burning conditions with a maximum fireline intensity of almost 4000 kW m⁻¹.     

Rangeland biodiversity assessment using fine scale on-ground survey,time series of remotely sensed ground cover and climate data: an Australian savanna case study

Savanna rangelands are undergoing rapid environmental change and the need to monitor and manage landscape health is becoming increasingly an imperative of government agencies and research organizations. Remotely sensed ecological indicators of disturbance offer a potential approach, particularly in the context of issues of scale required to assess and monitor extensive rangeland areas. The objective of this research is to analyse the potential of spatially explicit ecological indicators of disturbance to explain the spatial variability in species diversity and abundance (including introduced flora species) in rangelands. For two mapped rangeland ecosystem types in northern Australia, regression analysis was used to explore the relationships between species diversity and abundance, and remotely sensed ground cover time series statistics, foliage projective cover, and a precipitation deficit index. It was assumed that the ecosystem types used had been mapped to represent uniform vegetation units and consequently predictors of environmental heterogeneity were not used in the regression analysis. It was found that the predictor variables performed well in explaining the variation in species diversity and abundance for the more open, homogenous and less topographically complex basalt ecosystem type and less effectively for the more structurally complex, more wooded and less disturbed metamorphic ecosystem type. The results indicate that, for mapped ecosystem types with low heterogeneity and topographic complexity, ground cover temporal mean and variance are potentially useful indicators of disturbance to species diversity and abundance, provided the local spatial variability in the climate signal is accounted for.