Methane emissions are lower from reindeer fed lichens compared to a concentrate feed

Methane emissions from reindeer ( Rangifer tarandus tarandus ) fed lichens (mainly Cladonia stellaris ) and a concentrate feed were determined using open-circuit respirometry. The lichen diet was low in crude protein ( 4 weeks prior to experiments and methane emissions recorded for two separate 23 h periods for each diet. Methane emissions increased on average by 0.93 g/h (or by 5.8 times) in the first hour after feeding the concentrate feed, while emissions remained unchanged after the intake of lichens. Mean methane emissions from reindeer (n = 5) were 7.5 ± 0.54 (SE) g CH 4 day −1 when fed lichens, compared to a higher emission ( p = 0.001) of 11.2 ± 0.54 g CH 4 day −1 on the concentrate diet. The mean proportion of gross energy intake lost as methane was 5.2 ± 0.37% on the lichens and 7.6 ± 0.37%, or some 50% higher, on the concentrate feed. This difference was significant ( p < 0.001). Our results suggest that it is of environmental importance to preserve the lichens on the tundra and minimize supplementary feeding with concentrate diets, in order to reduce methane emission.