Ecological role of reindeer summer browsing in the mountain birch (Betula pubescens ssp. czerepanovii) forests: effects on plant defense, litter decomposition, and soil nutrient cycling

Stark, Sari; Julkunen‐Tiitto, Riitta; Kumpula, Jouko

doi:10.1007/s00442-006-0593-y

Cited by 56 publications

(34 citation statements)

References 53 publications

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“…Differences between fungal genotypes in the balancing of N-and C-metabolism might thus cause the differential mycorrhizal effects on the N supply of host plants (Table 2). In agreement with Stark et al (2007), we found a close overall relationship between the foliar concentrations of N and secondary substances (total phenolics) (Fig. 2).…”

Section: Interactions Between Host Genotype and Fungal Strainsupporting

confidence: 86%

The significance of host-fungus combinations in ectomycorrhizal symbioses for the chemical quality of willow foliage

et al. 2009

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The majority of plants interacts with mycorrhizal fungi, which predominantly provide mutual benefits, but also costs. We tested the hypothesis that specific combinations of host plants (four commercial varieties of Salix spp.) and ectomycorrhizal partners (species of Laccaria, Paxillus, Tricholoma and Hebeloma) differ in their effects on the host foliar chemistry. Twenty specific host -mycorrhiza combinations were pot-grown outdoors under low-N conditions. Foliar concentrations of total phenolics and salicylic acid were decreased by mycorrhizas in S. schwerinii x S. viminalis and S. x dasyclados genotypes, but increased in S. viminalis. Mycorrhiza effects on host biomass production were positive, indifferent or negative, depending on the specific host-mycorrhiza combination. The host plant genotype influenced mainly the direction of mycorrhizal effects on foliar chemistry, whereas the magnitude of mycorrhizal effects varied mostly among the fungal genotypes. The results are relevant with respect to the possible interactions between mycorrhizas, plants and leaf herbivores.

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Section: Interactions Between Host Genotype and Fungal Strainsupporting

confidence: 86%

The significance of host-fungus combinations in ectomycorrhizal symbioses for the chemical quality of willow foliage

et al. 2009

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“…form tannin-protein complexes, or be degraded or leached. In litter bag experiments with both spruce litter (Lorenz et al 2000) and birch litter (Stark et al 2007), tannins were lost rapidly, in some cases more than 80%, during the first year. As discussed above, in the field the concentration of total water-soluble phenolic compounds, condensed tannins and total tannins generally decreased from the litter layer to the humus layer but not as drastically as was the case with several terpenes, and the decrease was dependent on tree species (Adamczyk et al 2008b;Kanerva et al 2008).…”

Section: Occurrence Of Phenolic Compounds In Plants and Soilmentioning

confidence: 98%

Nitrogen transformations in boreal forest soils—does composition of plant secondary compounds give any explanations?

Smolander¹,

Kanerva

Adamczyk³

et al. 2011

Plant Soil

121

103

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Two major groups of plant secondary compounds, phenolic compounds and terpenes, may according to current evidence mediate changes in soil C and N cycling, but their exact role and importance in boreal forest soils are largely unknown. In this review we discuss the occurrence of these compounds in forest plants and soils, the great challenges faced when their concentrations are measured, their possible effects in regulating soil C and N transformations and finally, we attempt to evaluate their role in connection with certain forest management practices. In laboratory experiments, volatile monoterpenes, in the concentrations found in the coniferous soil atmosphere, have been shown to inhibit net nitrogen mineralization and nitrification; they probably provide a C source to part of the soil microbial population but are toxic to another part. However, there is a large gap in our knowledge of the effects of higher terpenes on soil processes. According to results from laboratory experiments, an important group of phenolic compounds, condensed tannins, may also affect microbial processes related to soil C and N cycling; one mechanism is binding of proteins and certain other organic N-containing compounds. Field studies revealed interesting correlations between the occurrence of terpenes or phenolic compounds and C or net N mineralization in forest soils; in some cases these correlations point in the same direction as do the results from laboratory experiments, but not always. Different forest management practices may result in changes in both the quantity and quality of terpenes and phenolic compounds entering the soil. Possible effects of tree species composition, clear-cutting and removal of logging residue for bioenergy on plant secondary compound composition in soil are discussed in relation to changes observed in soil N transformations.

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“…At the Munkajaure site, which presumably was used more permanently, it is possible that the overall effect of lowintensity reindeer grazing, trampling and fertilization improved the establishment of birch (cf. Helle et al 1998, Stark et al 2007). Furthermore, just as tree species can respond individually to climatic changes (cf.…”

mentioning

confidence: 99%

Legacies of pre-industrial land use can bias modern tree-ring climate calibrations

Gunnarson¹,

Josefsson²,

Linderholm³

et al. 2012

Clim. Res.

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In Scandinavia, dendrochronological reconstructions of past climate have mostly been based on tree-ring data from forests in which there has been, supposedly, very little or no human impact. However, human land use in sub-alpine forests has a substantially longer history and more profound effects on the forest ecosystems than previously acknowledged. Therefore, to assess human influence on tree-ring patterns over the last 500 yr, we have analyzed tree-ring patterns using trees from 2 abandoned Sami settlements and a reference site with no human impactall situated in the Tjeggelvas Nature Reserve in north-west Sweden. The hypothesis was that landuse legacies have affected tree-ring patterns, and in turn, the resulting palaeoclimate in ferences that have been made from these patterns. Our results show that climate signals are strongest at the reference site and weakest at one of the settlement sites. From the 1940s to the present, tree growth at this settlement site has been significantly lower than at the reference site. Lower tree growth at old settlements may have resulted from rapid changes in the traditional land use, or following the abrupt change when the settlements were abandoned. Without site-specific knowledge of past land use, there is a high risk of accidently sampling trees that have been affected by human-induced disturbances in the past. This may create bias in the climate signals inferred from such trees, and hence bias the outcome of climate reconstructions. We therefore recommend sampling several separate sites in study areas to improve the robustness of inferences.KEY WORDS: Scots pine · Tree-rings · Maximum latewood density · Climate reconstruction · Human land use · Vegetation history Resale or republication not permitted without written consent of the publisherClim Res 53: [63][64][65][66][67][68][69][70][71][72][73][74][75][76] 2012 (TRW) is primarily correlated with mid-summer (July) temperature, while the maximum latewood density (MXD) is strongly associated with temperatures over the full length of the growing season (McCarroll et al. 2003, Grudd 2008, Gunnarson et al. 2011. Peak response for the growing season is found with temperatures from August and is related to development of latewood cells. While TRW may provide information on other climate and environmental influences, such as precipitation or duration of snow cover, MXD provides stronger and more robust signals of the warm-season temperatures and is thus a more powerful proxy for summer temperatures than TRW.Collecting tree-ring data from forests at high altitudes or latitudes is also preferable since they are often located in inaccessible areas, where direct anthropogenic disturbance, which can affect treegrowth patterns, has been (and still is) limited (Sano et al. 2009). In northern Fennoscandia, large numbers of dendrochronological analyses have been performed to improve reconstructions of past climate using tree-ring data from Scots pine Pinus sylvestris L. trees growing in remote sub-alpine forests (Briffa et ...

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Ecological role of reindeer summer browsing in the mountain birch (Betula pubescens ssp. czerepanovii) forests: effects on plant defense, litter decomposition, and soil nutrient cycling

Cited by 56 publications

References 53 publications

The significance of host-fungus combinations in ectomycorrhizal symbioses for the chemical quality of willow foliage

The significance of host-fungus combinations in ectomycorrhizal symbioses for the chemical quality of willow foliage

Nitrogen transformations in boreal forest soils—does composition of plant secondary compounds give any explanations?

Legacies of pre-industrial land use can bias modern tree-ring climate calibrations

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