The diet of goats, red deer and South American camelids feeding on three contrasting Scottish upland vegetation communities

Published source details Fraser M.D. & Gordon I.J. (1997) The diet of goats, red deer and South American camelids feeding on three contrasting Scottish upland vegetation communities. Journal of Applied Ecology, 34, 668-686.
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Summary

In the UK, with changes in subsidy payments in rural areas and imposition of production quotas, there is increased interest in integrating alternative grazing livestock such as red deer Cervus elaphus, goats Capra hircus and even South American camelids, on indigenous and sown swards traditionally grazed by sheep and cattle in upland Scotland.

This study investigated the diet composition over two seasons of goats, red deer and guanacos Lama guanicoe grazing three vegetation types typical of Scottish hill and upland ecosystems: a sown sward (perennial rye-grass Lolium perenne-dominated), an indigenous grassland (mat-grass Nardus stricta-dominated) and a dwarf shrub community (heather Calluna vulgaris-dominated).

Experimental sites: The Lolium and Calluna experimental sites were at the Macaulay Land Use Research Institute’s Glensaugh Research Station at Kincardine, Aberdeenshire (National Grid ref: NT 670800). The Nardus site was at the Institute’s Sourhope Research Station at Yetholm, Scottish Borders (National Grid ref: NT 840210).

Grazing plots: On the Nardus and Calluna communities the two plots for the grazing experiments were 3 ha each, on the more productive Lolium sward they were 1 ha each. Prior to the start of the experiment the Loilum sward had been grazed to less than 6 cm by red deer, the Calluna community had been grazed a stocking rate of less than 0.5 hinds/ha and the Nardus community at less than 1 seep/ha.

Each site was grazed during summer 1991, spring 1992 and summer 1992, each grazing session comprising a 5-day adjustment period and a 7-day diet measurement period.

Vegetation composition, structure and biomass: Vegetation composition and canopy structure were recorded using point quadrats. Above-ground biomass was determined but cutting samples of vegetation to the humus layer within randomly placed quadrats. Vegetation biomass was recorded before and after drying.

Diet analysis: Samples were collected using oesophageal-fistulated animals (see original paper) and analysed in the laboratory. In 1991 five cashmere x feral goats, three red deer and one guanaco were available and used for collection of samples; in 1992 five red deer and five guanaco were available and used.

On each vegetation type, all three animal species were selective feeders. Goat diet composition was more variable than either red deer or guanaco. All three species were more selective when grazing the indigenous communities than when grazing the more productive Lolium-dominated sown sward.

Rye-grass sward: On the Lolium sward (containing also nine species of other grasses and nine dicotyledons including white clover Trifolium repens), guanacos avoided clover and the other dicots, whilst the goats and red deer consumed green leaves from all plant categories found at or near the sward surface.

Mat-grass community: On the Nardus community, all three species avoided the mat-grass tussocks, selecting green lamina of broader-leaved grasses from the species-rich inter-tussock areas. Between-species differences in minor components included an increased contribution of non-grass monocotyledonous plants to goat diet in spring, and a higher proportion of grass flowerstem and grass seed/flowerhead in guanaco diet in summer.

Heather community: The diets of the three species of animal on the Calluna community were broadly similar. All generally avoided heather and strongly selected graminoid species. Consumption of grass was greater in spring than summer.

Conclusions: Three ruminant species investigated in this study showed differences in diet composition, particularly on the native vegetation communities dominated by mat-grass and heather. This in turn might facilitate vegetation management and improve animal output.

Note: If using or referring to this published study, please read and quote the original paper.