The Vertebrate Scavenger Community Along a Boreal Forest-Alpine Gradient: The Importance of Ungulate Management, Small Rodent Cycles and Winter Climate

• Main Author: Gomo, Gjermund
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: 2020
• Subjects: Skandinavia; central Scandinavia; temperature; snow depth; moose; Alces alces; scavenging patterns; scavenging communities; small rodent abundance; reindeer; Rangifer tarandus; red fox; Vulpes vulpes; common raven; Corvus corax; wolverine; Gulo gulo; Eurasian jay; Garrulus glandarius; golden eagle; Aquila chrysaetos; VDP::Matematikk og Naturvitenskap: 400::Zoologiske og botaniske fag: 480; Fennoscandia
• Online Access: https://hdl.handle.net/11250/2690242

While the importance of carrion and scavenging is increasingly acknowledged, there are relatively few empirical studies of the scavenging community in Fennoscandia. There is limited knowledge on how habitat and potentially important drivers like winter climate, productivity, human subsidies or small rodent cycles affects the scavenger guild. The objectives of my thesis were to investigate 1) the structure of the winter scavenger community across a forest-alpine gradient in central Scandinavia and the effects of temperature and snow depth; 2) effects of large quantities of gut piles left behind during the moose (Alces alces) harvest on scavenging communities and the influence of energy content and gut pile density on scavenging patterns; 3) how fluctuating small rodent abundance, landscape productivity and snow depth affected red fox scavenging during autumn and winter in forest and alpine habitat. To meet these objectives camera traps were set up on gut piles from moose harvest in autumn and on baits consisting of frozen blocks of discarded reindeer (Rangifer tarandus) meat, fat and connective tissue in winter. Spatial variation in snow depth along the forest-alpine gradient interact with habitat to shape the structure of the scavenger community, while the impact of snow depth and temperature on species richness were weak in both forest and alpine habitats. When examining species separately diverse effects were observed, and most variation in individual species occurrence at baits was also explained by snow depth and habitat. Increasing snow depth only had negative effect on occurrence at baits for the species with stronghold in forest. The habitat generalists, and the alpine species showed no effect from climatic conditions at baits in alpine areas, but occurrence at baits in forest declined with decreasing snow depth and increasing temperature for red fox (Vulpes Vulpes), common raven (Corvus corax) and wolverine (Gulo gulo). Besides from the forest species Eurasian jay (Garrulus glandarius) which had a high ...