The annual diet of feral goats (Capra hircusL.) in lowland rimu-rata-kamahi forest on eastern Mount Taranaki (Mt Egmont)

Abstract

The diet of the feral goat (Capra hircus) in rimu-rata-kamahi forest on Mt Taranaki was examined over 1 year from monthly rumen samples. Seasonal changes in diet, relative plant preference ratings, and differential fragmentation and digestion rates of plant species, were measured. Individual rumens contained 19 plant species on average and sometimes more than 30. Two species, (Asplenium bulbiferum and Ripogonum scandens), made up 44.8% of the total volume eaten over the year. Foods which were eaten in significantly different proportions by season included Coprosma grandifolia, Coprosma tenuifolia, Griselinia littoralis, Melicytus ramiflorus, Ripogonum scandens (fruit and vine), Weinmannia racemosa, and Dicksonia squarrosa. Goats selected or rejected different plant species largely independently of plant availability. Schefflera digitata was relatively scarce in the habitat, but was possibly the most preferred food. In contrast, the very abundant Microlaena avenacea, Uncinia spp., moss, Alsophila smithii, and especially Blechnum fluviatile, were among those most avoided. Differential fragmentation and digestion experiments showed that the fern Asplenium bulbiferum was underestimated in the diet.