Disrupted trophic interactions affect recruitment of boreal deciduous and coniferous trees in northern Europe

Abstract

Abstract. Loss of large carnivore populations may lead to increased population densities of large herbivores, and subsequent cascading effects on the composition, structure, and function of ecosystems. Using a macroecological approach based on studies in multiple boreal forest landscapes in the Baltic Sea region and Russia, we tested the hypothesis that disrupted trophic interactions among large carnivores and large herbivores affect the recruitment of both ecologically and economically valuable tree species. We measured damage levels on young trees and large herbivore density in 10 local landscapes representing a gradient from extinct to extant populations of both large carnivores and large herbivores. We also tested the alternative hypothesis that forest management intensity is correlated to reduced recruitment of these tree species. At the macroecological scale there was an inverse relationship between the number of large carnivores and large herbivores. This coincided with a steep gradient in browsing damage on the ecologically important aspen, rowan and sallow as hosts for specialized species, as well as the economically important Scots pine. In one landscape hunting had replaced the presence of carnivores. Mean damage levels of these four tree species were correlated with large herbivore abundance, but not with forest management intensity. We discuss the pros and cons of this macroecological approach, as well as the challenge of governing and managing trophic interactions at multiple scales.

Wood production and biodiversity conservation are rival forestry objectives in Europe's Baltic Sea Region

“…, Angelstam et al. ). However, caution should be applied because too much focus on intensification of forest management for wood production threatens forest biodiversity.…”

“…Means (depictured as bars) and SE (as lines) of normalized values for four indicators of wood production (dark gray) and four of biodiversity conservation (light gray; Table 2), respectively, among the in the four regional case studies Bergslagen-M€ alardalen in Sweden, entire Latvia, Vitebsk oblast in Belarus, and Pskov oblast in Russia. easternmost case study regions with shorter landscape histories (Naumov et al 2016, Angelstam et al 2017b). However, caution should be applied because too much focus on intensification of forest management for wood production threatens forest biodiversity.…”

“…The steep west–east gradient in landscape history, ownership, and political culture within Europe's Baltic Sea Region (BSR) provides excellent opportunities to explore the consequences for the profile of benefits delivered by landscapes’ green infrastructures (e.g., Kern and Loffelsend , Metzger and Schmitt , Angelstam et al. , ). Following the enlargement of the European Union in 2004 by inclusion of the three Baltic States and Poland, the Baltic Sea has become close to an EU‐internal sea.…”

Impacts of wolves on rural economies from recreational small game hunting

“…Wolves may contribute by adding one more species, a charismatic top predator, to the ecosystems. The trophic effects of wolves are debatable (Allen et al 2017a;Allen et al 2017b;Bruskotter et al 2017;Kuijper et al 2016;Mech 2012;Mech 2017;Peterson et al 2014); however, it has been argued that if sufficiently abundant in the long term, wolves could lead to several potential cascading ecosystem effects on the recruitment of deciduous trees of importance for biodiversity conservation (Angelstam et al 2017;Angelstam et al 2000;Beschta and Ripple 2009), damages to economically important tree species (Angelstam et al 2017) and changing mesopredator populations (e.g. red fox (Vulpes vulpes), pine marten (Martes martes) (Elmhagen et al 2010;Ripple et al Fig.…”

The tree species matters: Biodiversity and ecosystem service implications of replacing Scots pine production stands with Norway spruce

“…Sweden has comparatively high-population densities of large herbivores (Angelstam et al 2017), including e.g. moose (Alces alces) and roe deer (Capreolus capreolus).…”