Feeding ecology of Konik horses and donkeys in Belgian coastal dunes and its implications for nature management

Foraging behaviour and diet selection of Koniks and donkeys were studied in order to estimate their possible impact on vegetation development and hence their appropriateness as nature management tools. Koniks show a larger intake rate and quantity than do donkeys. Koniks do not show significant seasonal differences in biomass intake, whereas donkeys consume significantly more in winter. Both animal species feed mainly on graminoids. The Konik diet is composed of 86\% of graminoids with an additional 12\% of herbs. The donkey diet consists of 69 \% of graminoids, which are mainly supplemented with browsing (18 \%), e. g. twigs and leaves of Ligustrum vulgare and Rubus caesius. Calamagrostis epigejos, Rosa pimpinellifolia (fruits), Carex arenaria and Arrhenatherum elatius are the most important plant species eaten by donkeys (based on number of bites and biomass). Koniks eat Calamagrostis epigejos significantly more, qualitatively (number of bites) as well as quantitatively (biomass intake), than any other plant species, but Cirsium arvense, Calamagrostis canescens, Juncus subnodulosus, Holcus lanatus and Claytonia perfoliata are also frequently consumed. Koniks as well as donkeys do eat plant species that nature managers would like to see decline in dominance, e. g. Calamagrostis epigejos, but browsing on scrub species is insufficient to decrease the area occupied by shrubs.