Merino Sheep Habitat Use in Canterbury High Country Tall Tussock Grasslands
Thesis DisciplineEnvironmental Sciences
Degree GrantorUniversity of Canterbury
Degree NameMaster of Science
Summary 1. The goals of this thesis were to determine whether Merino sheep use habitat at random. Specifically, this research was undertaken to identify areas of intensive use, determine daily activity patterns, explore habitat use between activities, between sheep, define home ranges and to explore the influence of weather on habitat use. 2. Sixteen Merino ewes were monitored using GPS collars recording locations every 15 minutes. A weather station was set up at 1380 m a.s.l. to record weather variables at the study site. 3. Merino ewes do not select and utilise habitat in proportion to its availability. Short tussock grassland was preferentially selected for despite having a low occurrence. Overall, ewes selected habitat that was within 400 metres of a water source, on slopes less than 30° and preferred easterly habitat. 4. Merino ewes utilised different habitat for different activities. The day was divided into grazing, resting and night camping, as determined from hourly movement, backed up by 10 days of visual observations. Grazing occurred mostly on flat to low slopes in short tussock grassland. Resting occurred mostly on the riverbed or on surrounding short tussock grassland. Night camping occurred at higher altitudes (~ 100 m higher) than the resting sites and was on steeper slopes, partly due to the U-shaped nature of the valley. Night camping occurred in tall tussock grassland and native mix habitat. Several night camps were used while a smaller number of grazing sites were used. 5. Sheep differed in their individual habitat use. Two sheep were explorers, one crossing the river to occupy adjacent land, and one sheep moved out of the original study area, passing through a narrow rocky gap. Some sheep stayed close to the main mobs, while others spread out in small groups. 6. Home ranges were affected by the presence of large mobs; those sheep in the main mob had smaller home ranges than those in smaller groups. Home ranges were also smaller in areas of higher quality forage. 7. Weather variables did affect sheep habitat use with rain having the most influence. One cold, wet, windy day resulted in sheep being less active while occupying the middle of the fan, so displayed a preference for grazing and resting at higher altitude than normal. Temperatures and wind had little effect on sheep habitat use.