Can the potential for tick infestation influence patterns of resource use by Eland (Taurotragus oryx)?

[摘要] The vegetation of the Kgaswane Mountain Reserve, in North West Province, South Africa,was mapped according to seven vegetation structure types, based on tree density and height,and grass height. Free-living ticks were collected by drag-sampling the vegetation from eachstructure type in November 2014, prior to the onset of the summer rains, and February 2015,once most of the seasonal rains had fallen. Eland (Taurotragus oryx) location informationwas recorded from four GPS collared cows over the two sample periods. Tick abundance wasconsistently lower in shorter, open, more exposed vegetation structure types, and higher inmore sheltered types. Position higher up in the landscape nullified the positive impacts oftrees on beneath-canopy microclimate in tall open woodlands, as indicated by comparativelylower tick numbers than in more sheltered woodland types. Tick abundance is influenced byvegetation structure and the availability of hosts. The majority of ticks trapped during bothperiods were larvae, with nymphs mostly present in November and adults mostly present laterin the season, indicating the seasonal nature of tick cohort recruitment. Eland calvingbehaviour centred on areas with low adult tick abundance. Eland did not respond to total tickabundance during either sampling period. They did select areas with low adult tickabundance, and avoided areas with high adult tick abundance. This corresponded with animprovement in upland forage quality, which allowed them to avoid foraging in areas withhigh adult tick abundance. It is plausible that the potential for infestation by adult ticks maybe a supplementary influence driving the use of space by eland.

[发布机构] University of the Witwatersrand