rsg_book_2013

MammalsFig. 1. The numbers of zebra, eland and giraffecounted during total-area counts from a helicopter ofthe wildlife on Shangani Ranch, Zimbabwe.monitoring. Wildebeestwere also released here inorder to contain them,because wildebeest maycarry a virus that causesmalignant catarrhal fever,which is potentially fatal tocattle.Post-release monitoring:There were three forms ofpost-release monitoring.First, there were incidentalobservations of groups ofre-introduced orsupplemented speciesduring cattle managementoperations. Sightings provided information about the spatial distribution anddispersal of released animals, and the presence of juveniles in the groupsindicated successful breeding. Secondly, whenever cattle management requiredcattle in a paddock to be rounded up, the staff - working on foot - searched theentire paddock and recorded the numbers of all wild herbivores that they saw. Inaddition to providing information on spatial distribution and breeding, these dataalso provided indices of abundance. Thirdly, usually every two years, all large,wild animals on each ranch were counted during a total-area survey, conductedfrom a helicopter flying at low level along parallel flight-lines.The helicopter surveys revealed that eland and zebra populations becameestablished on Shangani Ranch (Figure 1). A giraffe population also becameestablished, even though just six animals (all adult females) were released. Theincreased number of giraffe clearly resulted at least partly from immigration, eitherbecause immigrants were attracted by the released animals, or because ofdisruption caused onneighbouringproperties byZimbabwe’s agrarianreform program orboth. Giraffe releaseswere discontinuedbecause monitoringrevealed that thepopulation wasincreasing as a resultof this immigration.Foot patrols revealedthat the releases ofwaterbuck and sableantelope in theEland in plastic walled boma © Kevin Dunham140