Suchergebnisse

The performance of helicopter surveys for estimating population densities of
red kangaroos (Macropus rufus), eastern grey kangaroos
(Macropus giganteus) and common wallaroos
(Macropus robustus) was investigated by comparing
line-transect density estimates obtained from helicopter surveys with those
from ground (walked) surveys. Comparisons were made at four sites in central
western Queensland (areas with high densities of red kangaroos and common
wallaroos) that were surveyed during winter and summer from December 1991
until February 1995, and one site in south-eastern Queensland (an area of high
eastern grey kangaroo density) surveyed annually during autumn from March 1991
until March 1994. Helicopter surveys generally recorded lower sample sizes
than did ground surveys (means ± s.e = 34 ± 6%, 33
± 9% and 76 ± 2% lower for red kangaroos, eastern
grey kangaroos and wallaroos, respectively). Density estimates obtained from
the helicopter surveys were not significantly different from those obtained
from ground surveys for both red and eastern grey kangaroos as assessed by
repeated-measures ANOVA and regression analysis. However, helicopter surveys
of common wallaroos consistently returned density estimates about half those
of ground surveys. The relationships between the two methods did not differ
between winter and summer for any species. The conventional aerial survey
method for kangaroos of strip transects from fixed-wing aircraft has limited
ability to adjust for varying sightability conditions. Therefore, helicopter
surveys with line-transect sampling are an attractive alternative.

Background Despite increasing evidence on health inequalities over the past decades, further efforts to strengthen capacities to produce research on this topic are still urgently needed to inform effective interventions aiming to address these inequalities. To strengthen these research capacities, an initial comprehensive understanding of the health inequalities research production process is vital. However, most existing research and models are focused on understanding the relationship between health inequalities research and policy, with less focus on the health inequalities research production process itself. Existing conceptual frameworks provide valuable, yet limited, advancements on this topic; for example, they lack the capacity to comprehensively explain the health (and more specifically the health inequalities) research production process at the local level, including the potential pathways, components and determinants as well as the dynamics that might be involved. This therefore reduces their ability to be empirically tested and to provide practical guidance on how to strengthen the health inequalities research process and research capacities in different settings. Several scholars have also highlighted the need for further understanding and guidance in this area to inform effective action. Methods Through a critical review, we developed a novel conceptual model that integrates the social determinants of health and political economy perspectives to provide a comprehensive understanding of how health inequalities research and the related research capacities are likely to be produced (or inhibited) at local level. Results Our model represents a global hypothesis on the fundamental processes involved, and can serve as a heuristic tool to guide local level assessments of the determinants, dynamics and relations that might be relevant to better understand the health inequalities research production process and the related research capacities. Conclusions This type of knowledge can assist researchers and decision-makers to identify any information gaps or barriers to be addressed, and establish new entry points to effectively strengthen these research capacities. This can lead to the production of a stronger evidence base, both locally and globally, which can be used to inform strategic efforts aimed at achieving health equity.

A total of 2071 individual prey items were identified from 34 active and 55 inactive wedge-tailed eagle nests following the 1995, 1996 and 1997 breeding seasons. Overall, the eagle's diet was comparable to that reported in other studies within semi-arid regions, with rabbits, reptiles and macropods accounting for 47.8, 22.6 and 13.7% of prey items, respectively. In spring 1996 rabbit calicivirus moved into the study area, resulting in a 44-78% reduction in rabbit abundance (Sharp et al. 2001). An index was developed to enable the time since death for individual prey items to be approximated and a historical perspective of the eagle's diet to be constructed. Rabbits constituted 56-69% of dietary items collected during the pre-rabbit calicivirus disease (RCD) samples, but declined to 31% and 16% in the two post-RCD samples. A reciprocal trend was observed for the proportion of reptiles in the diet, which increased from 8-21% of pre-RCD dietary items to 49-54% after the advent of RCD. Similarly, the proportion of avian prey items was observed to increase in the post-RCD samples. These data suggested that prey switching may have occurred following the RCD epizootic. However, a lack of data on the relative abundances of reptiles and birds prevented an understanding of the eagle's functional responses to be developed and definitive conclusions to be drawn. Nevertheless, the eagles were observed to modify their diet to the change in rabbit densities by consuming larger quantities of native prey species.