Sheep, dingoes and kangaroos: new challenges and a change of direction 20 years on

Predation and competition are two primary forces limiting the extent to which sheep can be grazed in the Australian rangelands, particularly in Queensland. Dingo predation has been non-existent in much of the sheep zone since the localised eradication of dingoes in the early 1900s. Competition with kangaroos has been ever-present, but was previously managed (to some extent) by the commercial kangaroo harvesting industry. However, changes to dingo distribution and kangaroo densities and harvesting over the last 20 years have meant that dingo predation and kangaroo competition again threaten viable sheep production in the rangelands. Dingoes have increased their distribution and density in almost all sheep grazing areas and contemporary lethal control efforts are not preventing the decline of sheep. Loss of valuable international markets and moves to now harvest only adult male kangaroos means that the kangaroo harvesting industry produces little relief from kangaroo grazing pressure (given that kangaroo population growth is little affected by removal of adult males; see Finch et al. this volume). New approaches to dingo and kangaroo management are sorely needed to salvage and restore the production of sheep in the rangelands. In response, the installation and use of pest-proof fences is rapidly increasing in Queensland and other areas, facilitating, for the first time in nearly a century, the localised eradication of dingoes and the suppression of kangaroos to manageable numbers within fenced areas. We describe these challenges and opportunities for one site in particular (Leander Station), and offer a sheep grazier’s perspective on past and future use and management of problematic wildlife in sheep production zones

Issues in the Analysis of Capital Formation and Productivity Growth

macroeconomics,product growth, capital formation

Operational Time and Seasonality in Distributed Lag Estimation

The following paper discusses the analysis of some types of economic time series using an altered time scale, or operational time. It is argued that for some series, observations that are ordinarily thought of as equidistant in time are actually irregularly spaced in a more natural time scale. Section A discusses point or impulse sampling of related series and the estimation of distributed lag relationships between them. Section B discusses time-aggregated sampling. In Section C, operational-time methods are used to calculate the distributed lag relationship between starts and completions for single-family dwellings in the United States. The results are statistically compared with those of ordinary distributed lag methods.