Open access publications in the SLU publication database

Abstract

Over the past decades, ungulates across the northern hemisphere have been expanding in range and numbers. This has raised concerns about their impacts, particularly on shared resources with humans, e.g., timber trees. Understanding how different ungulate species use trophic resources is therefore a crucial component of managing their populations.

In this thesis, I synthesized data from the literature and used faecal DNA metabarcoding to investigate diets and patterns of resource partitioning for ungulate communities in Sweden and at the European scale. I also evaluated the reliability of dung morphometry for identifying ungulate species. I found that species identification of faecal pellets is difficult where similar-sized ungulates coexist which questions the reliability of pellet counts as a monitoring technique in such systems. Dung morphometry could, however, clearly distinguish moose from the smaller deer species. Across Europe, average diets of the four main deer species fit well with predictions by Hofmann’s hypothesis of ruminant feeding types. Red and fallow deer (mixed feeders) showed larger dietary plasticity than moose and roe deer (browsers). In Sweden, red and fallow deer adopted a more browser-like diet with high proportions of woody plant species in their diet. Dietary niche width was lowest for moose and highest for fallow deer but varied only little across seasons. Ericaceous shrubs like Vaccinium spp. comprised a major component in the diet of all four deer species. Intraspecific dietary overlap for moose was higher than dietary overlap with either of the smaller deer species. Moose diets also contained larger proportions of Scots pine Pinus sylvestris than those of the other deer species. In areas with high densities of the smaller deer, moose, but not the other deer species, consumed more pine and less Vaccinium spp. Feeding competition from the smaller deer species over Vaccinium spp. may drive moose towards increased browsing on pine, thereby exacerbating the forestry-moose conflict.

For the mitigation of this conflict, managing important food items like Vaccinium spp. and the populations of smaller deer species may be of equal or greater importance than a simple reduction in the number of moose.