Doctoral defence: Eliisa Pass “The effect of managed forest-wetland landscapes on forest grouse and nest predation”

On 8 December at 10:15 Eliisa Pass will defend her doctoral thesis "The effect of managed forest-wetland landscapes on forest grouse and nest predation" for obtaining the degree of Doctor of Philosophy (in Zoology and Ecology).

Supervisors:
Professor Asko Lõhmus, University of Tartu
Research Fellow Marko Mägi, University of Tartu, Estonian Environmental Board

Opponent:
Associate Professor Grzegorz Mikusiński, Swedish University of Agricultural Sciences (Sweden)

Summary

Viable forest grouse populations (capercaillie, black grouse and hazel grouse) indicate landscape integrity, and maintaining such landscapes also protects other species. In the Nordic and Baltic countries, natural forest-wetland landscapes have been transformed by extensive afforestation, thinning and drainage systems. During the recent decades, the named landscapes have been altered into patches of fragmented woodland with increasing nest predation risk in birds. Along with the changes, the populations of forest grouse in these landscapes have also declined. All three species prefer different habitats in the same landscape and are sensitive to predation and forest management. I investigated how to improve the species survival. For that, I evaluated which silvicultural practices increase nest predation, and in which habitats the species are most vulnerable to predation. Clearcuts and young stands have the lowest nest predation, but capercaillie and hazel grouse avoid these areas. Forest fragmentation by clearcuts can cause both birds and predators to concentrate into remained patches of middle-aged and old-growth forest, increasing thus predation risk. Drainage ditches do not have a direct impact on grouse, but each species prefers a different type of Histosols. Thus, the abundance of variuous Histosols requires undrained forest-wetland landscape. The most unsuitable habitat for grouse are small protected areas, surrounded by production forestry with various silvicultural techniques. Unmanaged or minimally managed natural landscapes favour viable grouse populations. Conservation of such landscapes is crucial - even if drained habitats are being restored, breeding success decreases and nest predation risk increases shortly after the restoration. Culling nest predator species would provide temporary relief, but this would only have a local short-term effect.

The defense can also be followed on Zoom: https://ut-ee.zoom.us/j/94891251061?pwd=dnp5SHVpL040WGMzdHFHWW9LKzB3Zz09 (Meeting ID: 948 9125 1061, Passcode: 495752).