A Grazer in a Browser's Habitat: Resource Selection of Foraging Cattle in Productive Boreal Forest

Abstract

In Norway, cattle (Bos taurus) are released to large areas of boreal forest for summer grazing. To determine to what degree this practice challenges timber production and wildlife management, we need a better understanding of basic cattle ecology. What do cattle, typical grazers, feed on in a habitat typically used by browsers? We determined cattle's resource use and selection at three scales: habitat and microhabitat selection when foraging and diet selection. Boreal forest is dominated by grass-poor habitats, and despite their strong selection for grass-rich habitats, cows spent a lot of time in suboptimal habitats, like old bilberry (Vaccinium myrtillus) spruce (Picea abies) forest. However, they managed to find grass-rich habitat patches within those, selecting for patches with bentgrass (Agrostis spp.). Graminoids, mainly wavy hair-grass (Avenella spp.), tussock grass (Deschampsia), and true sedges (Carex spp.), made up the biggest part of the fecal samples. Woody plants, mainly willow (Salix spp.), Vaccinium spp., pine (Pinus spp.), and birch (Betula spp.), made up 9.4% ± 4.7% of the samples, a value lower than reported for other forest grazing cattle. Cattle avoided woody plants in their diet and selected for graminoids. They preferred deciduous over coniferous species. At these low stocking densities, the cows were grazers in this browser's habitat. Moreover, they selected rather on habitat and patch scale than for individual plants within a given habitat patch, considered typical for a grazer. Their grass-rich diet indicates little overlap with the diet of local wild ungulates, which are mostly browsers. Their aversion of spruce and selection for graminoids and deciduous trees indicates low conflict risk for browsing damages and even a beneficial weeding effect on trees planted for timber production.