Minna Turunen

Does climate change influence the availability and quality of reindeer forage plants

The northward and upward movement of the tree line and gradual replacement of lichens with vascular plants associated with increasing temperatures and nutrient availability may change the reindeer pastures in Northern Fennoscandia. The productivity of reindeer forage will most probably increase, but their protein (nitrogen) concentrations may decrease because of higher temperatures and CO2 concentration. In the long term, the nutritive value of forage will depend on the mineralization rate and nutrient uptake from the soil. Enhanced UV-B is likely to increase the concentration of phenolics, decreasing forage quality and choice, but reindeer may adapt to increased phenolics. Increased winter precipitation, the occurrence of ice layers, deeper snow cover, and the appearance of molds beneath the snow cover may reduce the availability and/or quality of reindeer forage, but prolongation of snowless periods might have the opposite effect. The net balance of negative and positive effects will vary regionally depending on the climate, bedrock, vegetation, reindeer herding systems and socio-political factors. Multidisciplinary research is needed most importantly on the effects of the changing winter climate on reindeer forage, and the effect of modified forage quality on reindeer physiology.

Nitrate reductase activity in some subarctic species and UV influence in the foliage of Betula pendula Roth. seedlings

Nitrate reductase (NR) activity was studied in the foliage of five subarctic species: mature trees of European white birch (Betula pubescens Erch. S.S.), Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies L. Karst), Ericaceous shrub bilberry (Vaccinium myrtillus L.), naturally growing in a forest, and seed-grown silver birch (Betula pendula Roth.) seedlings in an ultraviolet (UV) exclusion field experiment at the Pallas-Ounastunturi National Park in Finnish Lapland (68 degrees N). Mean NR activity ranged from 0 in bilberry to 1477 (S.D. = 277.7) and 1910 (S.D. = 785.4) nmol g(-1) DW h(-1) in mature trees of European white birch and silver birch seedlings, respectively. Significant differences due to UV exclosure treatments were determined for the NR activity of silver birch seedlings (F = 3.62, P= 0.025*) after three growing seasons (191 days) of UV exclusion. The ambient and control silver birch seedlings had or tended to have higher NR activity than those grown under UV exclusion. No relationship was found between the foliage NR activity and total nitrogen content, which ranged from 0.61 to 1.35% per seedling. The present study suggests large differences in NR activity between the species and the induction of NR activity in silver birch seedlings due to ambient UV radiation.

Effect of the temperature and the exclusion of UVB radiation on the phenolics and iridoids in Menyanthes trifoliata L. leaves in the subarctic

The long-term effects of UVB exclusion and temperature on the methanol extractable (ME) phenolics (flavonoids, phenolic acids) and iridoids of Menyanthes trifoliata L. (Mt) leaves were studied in northern Finland (68 degrees N) using wooden frames covered with filters for UVB exclusion (polyester filter), control (cellulose acetate filter) and ambient (no filter) conditions. Analysis of ambient plots showed no effect of the daily mean temperature (2sigma = 1.58 degrees C) on the leaf ME compound content and composition, but minimum temperatures decreased the flavonol content. UVB exclusion did not affect the total ME compound content but significantly decreased the proportion of flavonols concomitantly with an increase in iridoids. Due to its high iridoid content, Mt appears as an interesting model plant for studying the iridoid biosynthesis and its regulation under stress conditions.

The chemical response of reindeer summer pasture plants in a subarctic peatland to ultraviolet (UV) radiation

Reindeer management is an important livelihood in northern Fennoscandia. There are about 0.7 million reindeer in Finland, Sweden and Norway and approximately 300,000 calves are born every year. The survival of reindeer is highly dependent on renewable natural resources, or ecological preconditions provided by natural pastures (Helle et al. 1990; Reimers 1997; Kumpula et al. 1998). Summer pastures play a central role in the growth of reindeer. Reindeer calves are born in spring and their growth is most rapid during the first few months of life when they graze on summer pastures. Reindeer are mainly slaughtered during autumn. Most of the slaughtered animals are calves (>70 %), and the productivity of reindeer management and income of reindeer herders is highly dependent on the growth success of the calves during the summer. Body mass and fat stores that reindeer are able to accumulate on the summer pastures significantly affect the condition of reindeer and their survival over winter (Helle et al. 1987; Soppela 2000; Soppela and Nieminen 2002). The diet of reindeer is markedly different between summer and winter. During summer, reindeer feed on green vegetation such as grasses, sedges, shrubs, herbs, and leaves of deciduous trees (Warenberg et al. 1997). This diet has a high content of energy, protein, and minerals (Nieminen and Heiskari 1989; Staaland and Saebo 1993) and it enables rapid growth of reindeer and accumulation of muscle and fat. During autumn and early winter, reindeer gradually change to a diet consisting mainly of lichens and wintergreen parts of shrubs, sedges, and grasses (Warenberg et al. 1997). The main winter feeds in many areas are ground lichens (Cladina spp.; Kumpula 2001). Winter diet has a low content of nitrogen and minerals (Nieminen and Heiskari 1989; Staaland and Saebo 1993; Danell et al. 1994; Storeheier et al. 2002). Lichens

Needle Structures and Epiphytic Microflora of Scots Pine (Pinus Sylvestris L.) under Heavy Ammonia Deposition from Fur Farming

Scots pine (Pinus sylvestris) needles from forest sites differing in distance from big fur farms emitting large amounts of ammonia and ammonium (=NHy) were examined by scanning and transmission electron microscopy. Specific features indicating an ammonium-nitrogen overload, such as an abundance of needle surface organisms and modifications in cellular and wax structures, were classified. Throughout the study area (up to 1000 m from the farms), mesophyll cells had thin cytoplasm and folding plasmalemma indicating frost damage. Phloem damage attributable to a possible nutrient imbalance was also observed. Chloroplast membranes were undulating and the occurrence of leaf surface organisms (e.g. aerophilic algae) was more abundant at the closest sites. The changes were related both to the direct effects of dry NHy deposition on the needles, and to the effects operating via soil acidification. The needle epicuticular waxes proved to be structurally rather inert against the influence of ammonium compounds, since no significant changes due to NHy were observed.

Observations on the Effects of Acid Rain Treatment on Needle Surfaces of Scots Pine and Norway Spruce Seedlings

Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies L. Karst.) seedlings were subjected to acid rain treatment at pH 3, pH 4 and pH 7 in a field experiment during 1986-1989. SEM+EDS, TEM, and measurements of wax quantity were used to detect changes in needle surfaces. After 5 weeks at pH 3 and pH 4 acid rain treatment, CaSO4 - crystallites were observed on visibly undamaged pine and spruce needle surfaces. Direct acid rain damage in conjunction with CaSO4 - crystallites was observed only occasionally in wax structures. Two-month-old pine needles had 50% less wax in early August after exposure at pH 3 and pH 4 than water controls. The occurrence of CaS04 -crystallites on acid rain-treated needle surfaces, and more abundant deposition of Ca oxalate crystallites in the inner walls of epi- and hypodermal cells could be involved with acid rain-induced calcium leaching. Calcium sulphate is probably a result of the disturbed wax and cuticle biosynthesis resulting in undeveloped, permeable cuticles. At the end of experiment, no CaS04 - crystallites were seen on needle surfaces. Soil analysis revealed an increase in the soluble Ca concentrations at pH 3.

Impacts of winter feeding of reindeer on vegetation and soil in the sub-Arctic: insights from a feeding experiment

The overall impacts of winter feeding, including the effects of both forage and reindeer (Rangifer tarandus), were studied in an experiment in the Hammastunturi herding cooperative (68°N), Finland, with 300 reindeer in a sub-xeric heath forest (35 ha) during March/April 2009 and 2010. The feeding practices on the 50 plots were: (1) feeding with grass silage+hay with leftovers cleared in the spring; (2) feeding with grass silage+hay with leftovers not cleared; and (3) feeding with pellets. In addition, (4) unfenced and (5) fenced control plots were included, on which the reindeer were not fed. No invasive plant species introduced through grass silage+hay were observed on the plots. The coverage of Deschampsia flexuosa increased on grass silage+hay plots after the first winter, and both coverage and height of the grass increased after the second winter. The coverage of Dicranum sp. and Pleurozium schreberi was lower on plots where reindeer were fed with grass silage (leftover silage not cleared) vs. controls. Some dwarf shrubs, e.g., Calluna vulgaris, showed a similar response after the second winter. The N content of Empetrum nigrum was higher on grass silage plots (leftover silage not cleared) after the first winter vs. controls. After two winters, the N content of both E. nigrum and Vaccinium myrtillus was increased. Of the soil variables studied, C/N decreased on grass silage+hay plots vs. fenced controls. We conclude that even a moderate level of feeding may cause changes that can lead to a gradual shift from nutrient-poor heath forest towards a more nutrient-rich type. To access the supplementary material for this article, please see the supplementary files under Article Tools online.

Different response of two reindeer forage plants to enhanced UV-B radiation: modification of the phenolic composition

The long-term effects of enhanced UV-B radiation on the content and composition of leaf phenolics in Epilobiumangustifolium L. and Eriophorumrusseolum Fries ex Hartman were studied in northern Finland (68°N) using two UV-B enhancement experiments, both simulating UV-BCIE radiation and corresponding to a 20% loss of ozone layer. High proportions of hydrolyzable tannins (69%) and condensed tannins (66%) characterized both Epilobium and Eriophorum leaves, respectively. No UV treatment effect was detected in the content or composition of Epilobium leaf soluble phenolics, whereas significant UV effects were detected in Eriophorum leaves in a developmental-specific manner. At the end of the growing season, the proportion of total soluble phenolics was higher in leaves exposed to enhanced UV-A and UV-B radiation than in the control leaves, but the phenolic composition was not significantly modified. This study introduces a new example on plants’ phenolic response to UV radiation being species-specific and detectable only at certain developmental stages. Possible consequences of increased phenolic content in forage plants for selection and digestibility by reindeer are, however, not yet known.

Effects of Ozone Exposures on Epicuticular Wax of Ponderosa Pine Needles

Two-year-old ponderosa pine (Pinusponderosa L.) seedlings were exposed during the 1989 and 1990 growing seasons to ozone in open-top chambers placed in a forested location at Shirley Meadow, Greenhorn Mountain Range, Sierra Nevada. The ozone treatments were as follows: charcoal-filtered air (CF); charcoal-filtered air with addition of ambient concentrations of ozone (CF + O3); and charcoal-filtered air with addition of doubled concentrations of ozone (CF + 2 x O3). Ozone effects on ponderosa pine seedlings progressed and accumulated over two seasons of exposure. Throughout the first season, increased visible injury and accelerated senescence of the foliage were noted. Subsequently, during the second season of ozone exposure, various physiological and biochemical changes in the foliage took place. All these changes led to reduced growth and biomass of the seedlings. Epistomatal waxes of needles from the CA + 2 x O3 treatment had an occluded appearance. This phenomenon may be caused by earlier phenological development of needles from the high-ozone treatments and disturbed development and synthesis of waxes. It may also be caused by chemical degradation of waxes by exposures to high ozone concentrations.

Characteristics and Geographical Distribution of the Changes in Scots Pine Needle Surfaces in Finnish Lapland and the Kola Peninsula

Effects of air pollution and a variety of other environmental factors on physicochemical characteristics of Scots pine (Pinus sylvestris L.) needle surfaces were studied in an extensive field investigation, comprising 114 sample plots (356 trees) on transect lines extending from the Nikel and Monchegorsk industrial complexes on the Kola Peninsula, Russia, across Finnish Lapland. Preliminary results from some of the investigated physicochemical parameters are presented in this paper. Condition of epicuticular wax structures, occurrence of particle deposition, fungal hyphae and insect damage on needle surfaces were investigated quantitatively under a scanning electron microscope, and needle wettability was measured in terms of contact angles. The investigated parameters showed great variability in terms of pollution, climate and ecology. Both the epicuticular wax erosion rate and needle wettability changed significantly faster during the first year on pines in Kola Peninsula, Russia (transect 1, extending to Monchegorsk) than on pines in Finland (transects 1,2,3,7). Site dependent effects, e. g., variation in ecological conditions of the sample plot, could be diminished by investigating the rate of change in the physicochemical parameter of pine needle surface during the first year, instead of using absolute values from different needle age classes.