Effects of reindeer grazing and forestry on ground lichens in Finnish Lapland

Abstract

Akujärvi A., Hallikainen V., Hyppönen M., Mattila E., Mikkola K., Rautio P. (2014). Effects of reindeer grazing and forestry on ground lichens in Finnish Lapland. Silva Fennica vol. 48 no. 3 article id 1153. 18 p. Highlights• Both reindeer grazing and forestry affect the cover and biomass of reindeer lichens.• Reindeer grazing has bigger impact than forestry.• The lichen cover was about five-fold and the biomass about fifteen-fold in the ungrazed (fenced) sites than in the grazed ones.• The decrease of not only the biomass, but also the cover of lichens, is alarming. AbstractReindeer husbandry and forestry are practiced in the same areas in northern Fennoscandia. Reindeer pastures have largely deteriorated. We aimed to quantify the separate and combined effects of reindeer grazing and forestry on the amount of ground lichens. To do this, we mapped and inventoried all larger enclosures (49) in Finnish Lapland where forest management practices were similar in both sides of the fence. The average time since fencing was 43 years. We recorded the cover and estimated dry biomass of ground lichens, as well as parameters describing forest stand characteristics. The effect of reindeer grazing on both the cover and estimated dry biomass of lichens was clear: in the ungrazed (fenced) sites, the lichen cover (35.8%) was on average 5.3-fold and the dry biomass (1929 kg ha -1 ) 14.8-fold compared with the corresponding estimates in the grazed sites (6.8% and 130 kg ha -1 ). The effect of forestry on lichens was smaller. In the grazed stands the cover and biomass of lichens were higher in the mature stands compared to the younger stand development classes, whereas in the ungrazed stands there were no significant differences between the development classes. Both reindeer grazing and forestry affect the cover and biomass of ground lichens. The influence of reindeer grazing is, however, much heavier than that of forestry. The decrease of not only the biomass, but also the lichen cover, is alarming. The decrease of lichen cover may hinder the recovery of reindeer pastures, which in the long run endangers the sustainability of reindeer husbandry.

Contrasting effects of reindeer grazing on CO2, CH4, and N2O fluxes originating from the northern boreal forest floor

“…Our previous study (K. documented significant effect of grazing on the biomass of lichens and mosses, but no effect was observed on dwarf shrub and grass biomasses. Lichens are the main winter forage for reindeer, and similarly to other studies (Akujärvi et al, 2014;E. Köster et al, 2013;Olofsson et al, 2010;Susiluoto, Rasilo, Pumpanen, & Berninger, 2008), reindeer grazing reduced the lichen biomass by more than 90% in our study areas.…”

“…Our previous study (K. Köster, Berninger, et al, ) documented significant effect of grazing on the biomass of lichens and mosses, but no effect was observed on dwarf shrub and grass biomasses. Lichens are the main winter forage for reindeer, and similarly to other studies (Akujärvi et al, ; E. Köster et al, ; Olofsson et al, ; Susiluoto, Rasilo, Pumpanen, & Berninger, ), reindeer grazing reduced the lichen biomass by more than 90% in our study areas. One additional important finding in our study was that grazing by reindeer did not create patches of bare soil, which was shown to be the case in studies conducted in tundra areas (Suominen & Olofsson, ; Väre et al, ).…”

“…They influence most of the Scandinavian Arctic, subarctic, and northern boreal regions, which are also expected to be significantly influenced by the climate change (Anisimov, Vaughan, Callaghan, et al, ). Reindeer can strongly influence plant diversity and species composition and consequently also the nutrient availability and carbon (C) balance of subarctic ecosystems (Akujärvi et al, ; E. Köster et al, ; Väre, Ohtonen, & Mikkola, ). The number of reindeer has declined in northern boreal areas, except for Scandinavia where it has remained stable or has even increased over the last decades (Vors & Boyce, ).…”

“…Reindeer can strongly influence plant diversity and species composition and consequently also the nutrient availability and carbon (C) balance of subarctic ecosystems (Akujärvi et al, 2014;E. Köster et al, 2013;Väre, Ohtonen, & Mikkola, 1996).…”

Influences of Reindeer Grazing on Above- and Belowground Biomass and Soil Carbon Dynamics

“…In his previous study, van der Wal (2006) pointed out that vegetation diversity and composition in tundra is strongly dependent on the reindeer density, and thus also from grazing pressure-areas with low reindeer density are lichen dominated, whereas areas with higher reindeer density are moss or grass dominated. Thus, reindeer grazing has a strong reducing effect on the biomass of lichens (Akujärvi et al, 2014;Köster et al, 2013;Olofsson et al, 2009Olofsson et al, , 2010Stark et al, 2000;Suominen and Olofsson, 2000;Susiluoto et al, 2008). At the same time, the biomass of Vaccinium sp.…”