Five herbivorous introduced mammals are sympatric in the central Southern Alps. All of these species have the potential to affect conservation values, yet the Department of Conservation at present monitors and mitigates the impacts of only one. We outline ecological arguments for multi-species management of sympatric herbivore pest impacts and use the two- species system of sympatric thar and chamois to highlight the need for multi-species management of the central Southern Alps alpine pest community.
Current monitoring of Himalayan thar (Hemitragus jemlahicus) populations in New Zealand involves a technique based on repeated observations by different, experienced observers. The method gives no measure of error and hence does nor allow for statistical comparison of repeated surveys. We outline a faster and cheaper technique that enables statistical comparison between surveys based on mark-recapture theory.
The breeding ranges of thar are described as they were in 1976 and 1984 and compared with previously described ranges in 1936, 1946, 1956 and 1966. Commercial hunting during 1972-1976 harvested about 32000 thar and along with habitat limits in some areas this slowed the rate of dispersal into new areas and eliminated thar from the periphery of their range in other areas. The rate of thar dispersal from the time of their liberation in 1904 until 1936 was non-linear and recalculation of their breeding ranges from 1936-1966 shows rates of dispersal consistent with an exponential curve.