Abstract

Climate change results in longer growing season, benefitting forage crop production in northern Norway. Wild goose populations take advantage of the increased access to this high-quality feed. European goose populations are increasing, triggering conflicts and economical losses for farmers. A warmer climate may open for higher yielding seed mixtures, with better tolerance against goose grazing. We tested eight different seed mixtures by adding five forage species in various combinations to a traditional, commercial seed mixture in a randomized block design, three replicates. Goose grazing was simulated by weekly cutting small plots (0.25 m2) fixed within 10.5 m2 larger plots. Cumulated biomass in the weekly cut small plots was compared to total yields from the large plots, harvested twice according to normal practice. No significant differences in biomass accumulation between seed mixtures of the weekly cut plots were identified, possibly due to large variation between replicates, harvest years and cutting regime. However, results indicate that several of the new mixtures containing Dactylis glomerata are higher yielding and tolerate intensified cutting better than the traditional mixtures. This suggests that traditional, commercial seed mixtures are not the best for grasslands subjected to intensive geese grazing. goose grazing, Northern Norway, Dactylis glomerata, field study, simulated grazing

Abstract

Farmers in Northern Norway frequently experience winter damaged fields caused by ice encasement. The economic consequences are severe due to loss of fodder and costs with reestablishment of swards. It is therefore important to choose the best available varieties for the local climatic and environmental conditions. We tested eight Norwegian cultivars of timothy (Phleum pratense), for tolerance to ice encasement and their regrowth capacity. Both old and new cultivars, and cultivars with good overwintering capacity and less biomass production were tested against more productive cultivars with less overwintering capacity. The experiment was a semi-field setup and plants were established in pots which were placed outside. Half of the pots were covered with ice and half were kept under snow cover. During four months, pots were brought, once per month, into a greenhouse for thawing and measurement of biomass production under normal growth conditions. The results indicate that the old winter hardy cultivar ‘Engmo’ is least affected by ice encasement but produces little biomass. The joint Nordic cultivar ‘Snorri’ produced most biomass of all the cultivars after a treatment with ice cover. In conclusion, there is a large difference between cultivars in ice encasement tolerance, and ice cover affected regrowth capacity far more than snow cover

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Abstract

Climate change-induced snow thaw and subsequent accumulation of ice on the ground is a potential, major threat to snow-dominated ecosystems. While impacts of ground-ice on arctic wildlife are well explored, the impacts on tundra vegetation is far from understood. We therefore tested the vulnerability of two high-arctic plants, the prostrate shrub Salix polaris and the graminoid Luzula confusa, to ice encasement for 60 days under full environmental control. Both species were tolerant, showing only minor negative responses to the treatment. Subsequent exposure to simulated late spring frost increased the amount of damaged tissue, particularly in S. polaris, compared to the pre-frost situation. Wilting shoot tips of S. polaris increased nearly tenfold, while the proportion of wilted leaves of L. confusa increased by 15%. During recovery, damaged plants of S. polaris responded by extensive compensatory growth of new leaves that were much smaller than leaves of non-damaged shoots. The results suggest that S. polaris and L. confusa are rather tolerant to arctic winter-spring climate change, and this may be part of the reason for their wide distribution range and abundance in the Arctic.

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Abstract

Birks et al. question our proposition that trees survived the Last Glacial Maximum (LGM) in Northern Scandinavia. We dispute their interpretation of our modern genetic data but agree that more work is required. Our field and laboratory procedures were robust; contamination is an unlikely explanation of our results. Their description of Endletvatn as ice-covered and inundated during the LGM is inconsistent with recent geological literature.