Aerial survey of kangaroos in South Australia 1978-1998: a brief report focusing on methodology

摘要: Twenty-one surveys have been conducted using a Cessna 182 in the pastoral zone of South Australia, covering twenty year period 1978 to 1998, flying same transects and method. Considerable attention has given observer training turnover rate observers low. The pilot flown all surveys. is bounded north west by dingo-proof fence. Large lakes areas terrain above 2000 ft elevation (notably Flinders Ranges) were excluded from survey, leaving surveyed area approximately 207 000 square km. Surveys are each July/August, with morning afternoon survey sessions. Transects run east/west 15 nautical miles (28km) apart. method followed what become standard for fixed-wing surveys: height 250ft (76m) ground (AGL), speed 100 knots (185 km h-1), 5 unit lengths (97 sec.) 7 sec. pause between animals counted 200 m wide strips side aircraft, demarcated streamers attached wing struts. A radar altimeter used maintain and, since 1989, global positioning system ensure adherence transect required groundspeed. Red kangaroos, western grey common wallaroos, emus goats other macro fauna noted (camels, horses, dingoes, ostriches, etc.). Standard correction factors applied throughout, except that, present paper, data recalculated reflect outcomes this workshop concerning move modified factors. results highlighted responsiveness kangaroo populations rainfall pasture availability. There statistically significant long-term trend towards higher numbers kangaroos study area, similar reds end 1982/1983 drought. Over 20 years, however, there no either or lower red kangaroos. Some analyses obtained aerial already presented due course, further will be elsewhere. Importantly, provide useful demonstration that harvesting can carried out without detriment populations.