Doctoral defence: Yehor Yatsiuk "Large tree-cavities as key structures for forest biodiversity"

On 9 June at 10.15 Yehor Yatsiuk will defend his doctoral thesis "Large tree-cavities as key structures for forest biodiversity" for obtaining the degree of Doctor of Philosophy (in Zoology and Ecology).

Supervisor: Professor Asko Lõhmus, University of Tartu

Opponent: Associate Professor Adam Felton, Swedish University of Agricultural Sciences (Sweden)

Tree cavities are diverse microhabitats important for biodiversity in wooded ecosystems. Ensuring a supply of tree cavities is also a way to increase habitat complexity and biodiversity in landscape management. This dissertation examines the specific features of large tree cavities, which are relatively scarce, associated with large trees, and have specific patterns of use by fauna. It starts from a literature review that collates the so-far published information, specifically related to functions of large tree cavities for fauna, their distribution patterns and development processes. This is complemented by four case studies that provide field data about large cavity stocks, dynamics, animal use patterns and preferences for cavity characteristics in temperate and hemiboreal European forests. In general, large tree-cavities are naturally rare, become even scarcer in forests managed for wood production, and only a fraction has characteristics suitable for a particular vertebrate species. However, there can be also hotspots of high cavity density in landscapes. Overall, relatively few animal species breed in large cavities due to a high predation risk, but these species are often red-listed and well known the public. In addition, large cavities are important locations of non-breeding use by animals for obtaining food and water, or for social interactions. Natural turnover of large cavities in forests is relatively fast, highlighting the importance of constant recruitment. Management for sustaining large cavity stocks has to take long-term perspectives to allow for slow tree-decay processes and tree-species diversity in stands, and to implement spatial planning to ensure presence of senescent trees along with production and human safety considerations.

Defence will be held in Oecologicum room 127 and Zoom (meeting ID 921 0051 4943, passcode: 013441)