The exact distribution of the maximum, minimum and the range of multinomial/dirichlet and multivariate hypergeometric frequencies

The exact distribution of the maximum and minimum frequencies of Multinomial/Dirichlet and Multivariate Hypergeometric distributions of n balls in m urns is compactly represented as a product of stochastic matrices. This representation does not require equal urn probabilities, is invariant to urn order, and permits rapid calculation of exact probabilities. The exact distribution of the range is also obtained. These algorithms satisfy a long-standing need for routines to compute exact Multinomial/Dirichlet and Multivariate Hypergeometric maximum, minimum, and range probabilities in statistical computation libraries and software packages.

Southward range expansion of the Mourning Gecko Lepidodactylus lugubris on mainland Australia and nearshore islands

The Mourning Gecko Lepidodactylus lugubris is a species that colonises areas of human habitation and its spread is assisted by humans. This note documents southward range expansion of this species down the Queensland coast.

Range size-abundance relationships in Australian passerines

Aim  To investigate the relationship between geographical range size and abundance (population density) in Australian passerines.
Location  Australia (including Tasmania).
Methods   We analysed the relationship between range size and local abundance for 272 species of Australian passerines, across the whole order and within families. We measured abundance as mean and maximum abundance, and used a phylogenetic generalized least-squares regression method within a maximum-likelihood framework to control for effects of phylogeny. We also analysed the relationship within seven different habitat types.
Results  There was no correlation between range size and abundance for the whole set of species across all habitats. Analyses within families revealed some strong correlations but showed no consistent pattern. Likewise we found little evidence for any relationship or conflicting patterns in different habitats, except that woodland/forest habitat species exhibit a negative correlation between mean abundance and range size, whilst species in urban habitats exhibit a significant positive relationship between maximum abundance and range size. Despite the general lack of correlation, the raw data plots of range size and abundance in this study occupied a triangular space, with narrowly distributed species exhibiting a greater variation in abundances than widely distributed species. However, using a null model analysis, we demonstrate that this was due to a statistical artefact generated by the frequency distributions for the individual variables.
Conclusions   We find no evidence for a positive range size-abundance relationship among Australian passerines. This absence of a relationship cannot be explained by any conflicting effects introduced by comparing across different habitats, nor is it explained by the fact that large proportions of Australia are arid. We speculate that the considerable isolation and evolutionary age of Australian passerines may be an explanatory factor.

The Viggers & Hearn conundrum : a kangaroo home range study with no implications for land management

1.
Viggers & Hearn (2005) examined the encroachment of native herbivores on to farmland.
They presented kangaroo home range estimates and pasture biomass data for
three sites in south-eastern Australia, then made broad management recommendations
regarding the preservation of remnant habitat.
2.
While Viggers & Hearn identified potentially important patterns, we believe that
their data were neither sufficient nor appropriate to reveal the processes that underlie
these patterns.
3.
Specifically, their study was unreplicated at the land-use level, used inappropriate
density estimates for their study populations, failed to measure resources adequately,
used flawed methods of home range analysis, and demonstrated limited understanding
of key concepts and of their study species and thus could not draw valid conclusions.
4.
Synthesis and applications.
In view of these fundamental problems, we recommend
that decisions on the management of kangaroos

The foraging range of Little Penguins (Eudyptula minor) during winter

Although the movements of seabirds at sea during various stages of breeding in spring and summer have been the focus of many studies in recent years, there is still little known about the non-breeding period for most species. Satellite telemetry was used to determine the at-sea movements and foraging range of 47 Little Penguins (Eudyptula minor) from Phillip Island, south-eastern Australia, during the winter non-breeding period. Individuals conducting single-day trips (72% of individuals) typically foraged 8–14 km from the colony, whereas individuals conducting longer trips (28%; 2–49 days) foraged either within Port Phillip Bay or in the coastal waters of western Bass Strait at maximum distances of 62–147 km from the colony. Although there was no difference between sexes in duration of foraging trips, the overall foraging range of males (841 km2) was substantially smaller than that of females (1983 km2) across all months, and showed an overlap of only 34%. Our results show that the foraging range of Little Penguins in the non-breeding period is greater than that observed during the summer breeding period, which suggest a reduction in local food abundance in winter and highlights the importance of foraging areas distant to the colony during a time of increased energetic costs and higher mortality.

Low-cost interactive active range finder

This paper describes a new type of low-cost interactive active range finder and illustrates the effect of introducing interactivity to the range-acquisition process. The new range finder consists of only one camera and a laser pointer to which three LEDs are attached. When a user scans the laser, the camera captures the image of spots (one from the laser and the others from LEDs), and triangulation is carried out using the camera's viewing direction and the optical axis of the laser. The user interaction allows the range finder to acquire range data in which the sampling rate varies across the object depending on the underlying surface structures. Moreover, the processes of separating objects from the background and/or finding parts in the object can be achieved using the operator's knowledge of the objects.

Low-cost interactive active monocular range finder

This paper describes a low-cost interactive active monocular range finder and illustrates the effect of introducing interactivity to the range acquisition process. The range finder consists of only one camera and a laser pointer, to which three LEDs are attached. When a user scans the laser along surfaces of objects, the camera captures the image of spots (one from the laser, and the others from LEDs), and triangulation is carried out using the camera's viewing direction and the optical axis of the laser. The user interaction allows the range finder to acquire range data in which the sampling rate varies across the object depending on the underlying surface structures. Moreover, the processes of separating objects from the background and/or finding parts in the object can be achieved using the operator's knowledge of the objects.

Multiple emitter localization using range only measurements considering geometrical constraints

This paper proposes a constrained optimization approach to improve the accuracy of a Time-of-Arrival (ToA) based multiple target localization system. Instead of using an overdetermined measurement system, this paper uses local distance measurements between the targets/emitters as the geometric constraint.Computer simulations are used to evaluate the performance of the geometrically constrained optimization method.

Optimal sensor placement in range based localization for linear arrays

This paper investigates the linear separation requirements for range sensors in order to achieve the optimal performance in estimating the position of a target from multiple and typically noisy sensor measurements. We analyze the sensor-target geometry in terms of the Cramer-Rao inequality and the corresponding Fisher information matrix, in order to characterize localization performance with respect to the linear special distribution.

Phenological response of sea turtles to environmental variation across a species' northern range

Variations in environmental parameters (e. g. temperature) that form part of global climate change have been associated with shifts in the timing of seasonal events for a broad range of organisms. Most studies evaluating such phenological shifts of individual taxa have focused on a limited number of locations, making it difficult to assess how such shifts vary regionally across a species range. Here, by using 1445 records of the date of first nesting for loggerhead sea turtles (Caretta caretta) at different breeding sites, on different continents and in different years across a broad latitudinal range (25-39 degrees ' N), we demonstrate that the gradient of the relationship between temperature and the date of first breeding is steeper at higher latitudes, i.e. the phenological responses to temperature appear strongest at the poleward range limit. These findings support the hypothesis that biological changes in response to climate change will be most acute at the poleward range limits and are in accordance with the predictions of MacArthur's hypothesis that poleward range limit for species range is environmentally limited. Our findings imply that the poleward populations of loggerheads are more sensitive to climate variations and thus they might display the impacts of climate change sooner and more prominently.

How many seabirds do we need to track to define home-range area?

In recent years, marine predator and seabird tracking studies have become ever more popular. However, they are often conducted without first considering how many individuals should be tracked and for how long they should be tracked in order to make reliable predictions of a population's home-range area. Home-range area analysis of two seabird-tracking data sets was used to define the area of active use (where birds spent 100% of their time) and the core foraging area (where birds spent 50% of their time). Analysis was conducted on the first foraging trip undertaken by the birds and then the first two, three and four foraging trips combined. Appropriate asymptotic models were applied to the data, and the calculated home-range areas were plotted as a function of an increasing number of individuals and trips included in the sample. Data were extrapolated from these models to predict the area of active use and the core foraging area of the colonies sampled. Significant variability was found in the home-range area predictions made by analysis of the first foraging trip and the first four foraging trips combined. For shags, the first foraging trip predicted a 56% smaller area of active use when compared to the predictions made by combining the first four foraging trips. For kittiwakes, a 43% smaller area was predicted when comparing the first foraging trip with the four combined trips. The number of individuals that would be required to predict the home range area of the colony depends greatly on the number of trips included in the analysis. This analysis predicted that 39 (confidence interval 29-73) shags and 83 (CI: 109-161) kittiwakes would be required to predict 95% of the area of active use when the first four foraging trips are included in the sample compared with 135 (CI 96-156) shags and 248 (164-484) kittiwakes when only the first trip is included in the analysis. Synthesis and applications. Seabird and marine mammal tracking studies are increasingly being used to aid the designation of marine conservation zones and to predict important foraging areas. We suggest that many studies may be underestimating the size of these foraging areas and that better estimates could be made by considering both the duration and number of data logger deployments. Researchers intending to draw conclusions from tracking data should conduct a similar analysis of their data as used in this study to determine the reliability of their home-range area predictions.

Home-range, diet and breeding of a Powerful Owl Ninox strenua in East Gippsland, Victoria

Between 2004 and 2008 the diet and breeding success of a pair of Powerful Owls Ninox strenua were studied near Lakes Entrance, Victoria. In early November 2006 the adult female Powerful Owl was captured and radio-tracked for a period of 7.5 months. During this time the Owl's location was recorded on 111 occasions, including 65 nocturnal locations over 29 nights. Her home-range was calculated as 1589 ha using the Minimum Convex Polygon (MCP) method, or 871 ha based on the 95% Adaptive Kernel method. The area of forested habitat within the MCP home-range was 896 ha (the remainder representing cleared land). Her activity was centred primarily on the nesting gully where two dependent juveniles roosted, but several long-distance foraging expeditions (including roosting) that occurred more than 2.5 km from the juveniles were recorded. Arboreal mammals and birds dominated the Owls' diet. Low prey availability is suggested as being responsible for the single successful breeding event recorded in four nesting seasons.