Population dynamics and resource use of red deer after release from harvesting in New Zealand
- Arthur Rylah Institute for Environmental Research, Department of Sustainability and Environment, 123 Brown Street, Heidelberg, Victoria 3084, Australia
- Landcare Research, PO Box 40, Lincoln 7640, New Zealand
- Proteus Wildlife Research Consultants, PO Box 5193, Dunedin 9058, New Zealand
- Forest Research Institute, Rangiora, New Zealand
- Present address: 18 McKenzie Place, Rangiora 7400, New Zealand
Despite periods of extensive government-funded control, fluctuating commercial exploitation and ongoing recreational hunting, little is known about how red deer (Cervus elaphus scoticus Lönnberg) in New Zealand respond to the cessation of harvesting in terms of population growth rate and resource use. We describe the population dynamics and resource use of red deer in a montane catchment over 5 years (1962–67) following cessation of intensive government-funded control in 1961. Locations and sex–age classes of deer were observed monthly along a fixed route in the Harper-Avoca catchment, inland Canterbury. A total of 2036 red deer groups were observed. The number of groups observed annually increased during the study but no trends in median (2 or 3) or modal (1 or 2) group sizes were found. Population growth rates (r) of deer were extraordinarily high in the first two years (e.g. 2.33 ± 0.22 for adult females and 1.61 ± 0.23 for adult males), but decreased in subsequent years and were not biologically possible without substantial immigration and/or changes in detectability of deer. Sexual segregation and selection of vegetation types (alpine grassland, montane grassland, and forest) and 10 topographic landforms showed stronger intra-annual than inter-annual patterns. Segregation was greatest in spring and summer, least in the rut, and variable in winter. In all seasons, sexual segregation was greatest at 25- and 50-ha scales, moderate at 100-ha, and absent at the 500- and 1000-ha scales. Selection of vegetation types also varied seasonally, with deer of both sexes preferring montane grasslands in spring and summer and alpine grasslands in the rut. Backslopes were preferred landforms in spring and summer, spurs during spring and the rut, and hollows during the rut. Our results highlight the need to consider spatial scale, immigration, and detectability in the design of red deer culling and harvesting programmes. Studies of home-range size and use, migration patterns, dispersal rates and distances are required to better understand the impacts of red deer on New Zealand ecosystems and the effects of management on red deer populations.