Abstract
Today there is serious concern as to how intensive herbivore browsing affect organisms associated with browsing-prone woody plants. This project addresses interactions between deciduous trees in managed boreal forest and browsing by large ungulates (moose and roe deer). Specifically, we target aspen, one of the most valuable trees for biodiversity and how its recruitment is affected by ungulates in relation to tree cutting and fire. We aim at quantifying critical thresholds for co-existence of both aspen and large herbivores and estimate long-term dynamics of aspen. The project will provide new and fundamental understanding of how ungulate browsing affect abundance and distribution of aspen and species associated with this tree. To achieve this, we conduct comparative studies in landscapes with contrasting amounts of aspen and ungulates using series of exclosures. Furthermore, we perform experiments in split-plot design to unravel the relative importance of disturbance and browsing on aspen recruitment. A novel approach is that we assess temporal variability in demographic parameters in order to employ stage-structured deterministic and stochastic population modeling to forecast changes in aspen abundance. We also address the impact of environmental heterogeneity on ungulate habitat use, ranging behavior and utilization of aspen in a sequential series of analyzes at different spatial scales in order to gain better understanding of factors governing use.
Sweden