feral goat

Pronounced differences between the vegetation of four islands in a low-alpine lake compared to an adjacent mainland site are attributed to browsing by feral goats. The herbs Anisotome haastii and Ourisia macrocarpa are significantly more abundant on the islands, where they form tall herbfields. The grass Hierochloe recurvata and the shrub Gaultheria crassa were also more common on the islands, and were absent at the mainland study site.

The ability of feral goats to become pests is partly a consequence of the process of domestication. Neolithic people selected biological characteristics from wild goats, such as higher intrinsic rates of increase and increased sociability that have resulted in their domestic descendants becoming a particular nuisance when they escape to become feral. Feral goats live in about 11 % of New Zealand, mostly on land reserved for conservation of the indigenous biota. Their uncontrolled densities are usually less than 1 ha-1, but have reached 10 ha-1 in one area.