Goat pasturing—A biological solution to counteract shrub encroachment on abandoned dry grasslands in Central Europe?

Abstract

Shrub encroachment is one of the main causes of dry grassland loss in Central Europe. Abandoned semi-natural grasslands are often overgrown by thorny or spiny shrubs. Such unpalatable shrubs have frequently established by selective foraging during periods with low grazing pressure, particularly if sheep herding was performed. Feeding behaviour and diet selection vary between different livestock species and especially browsing goats are increasingly recognized for preventing woody encroachment. However, little is known about the appropriate timing of the grazing regime and the selection of woody species on abandoned dry grasslands already dominated by thorny and spiny shrubs.We quantified the foraging behaviour of Boer goats by direct observation on three encroached paddocks in the lower Saale River valley (Central Germany), which were grazed yearly from spring to autumn with a high stocking rate (0.6–0.8 LU/ha/yr). Feeding activities, the proportion of browsed woody species and identity of the browsed species were recorded in five minute intervals during a total of 30days in spring and 30days in summer/autumn. Dry grassland vegetation and woody coverage were observed on grazed and ungrazed 25-m2 plots for seven years.Contrary to other studies on grazing animals, we found that goats frequently browsed on spiny or thorny shrub species, if these species exhibited a high share of the shrub coverage. Altogether we detected a significant relationship between the abundance of woody species and browsing time on the respective species. The goats tended to spend more time browsing in spring than in summer/autumn. As a result of the browsing activity, we observed a significant decrease of woody coverage within pastures from 69.8% to 37.4% over seven years, which was positively related to the frequency of typical and endangered dry grassland species. An opposite trend was recorded on ungrazed plots.Therefore, goat pasturing with high-stocking rates and an early start in spring can be an efficient method for improving shrub-encroached dry grasslands during the restoration phase.