Browsing by Subject "SOIL"

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  • Felix, Benjamin; Sevellec, Yann; Palma, Federica; Douarre, Pierre Emmanuel; Felten, Arnaud; Radomski, Nicolas; Mallet, Ludovic; Blanchard, Yannick; Leroux, Aurelie; Soumet, Christophe; Bridier, Arnaud; Piveteau, Pascal; Ascensio, Eliette; Hebraud, Michel; Karpiskova, Renata; Gelbicova, Tereza; Torresi, Marina; Pomilio, Francesco; Camma, Cesare; Di Pasquale, Adriano; Skjerdal, Taran; Pietzka, Ariane; Ruppitsch, Werner; Canelhas, Monica Ricao; Papic, Bojan; Hurtado, Ana; Wullings, Bart; Bulawova, Hana; Castro, Hanna; Lindström, Miia; Korkeala, Hannu; Steingolde, Zanete; Kramarenko, Toomas; Cabanova, Lenka; Szymczak, Barbara; Gareis, Manfred; Oswaldi, Verena; Marti, Elisabet; Seyfarth, Anne-Mette; Leblanc, Jean-Charles; Guillier, Laurent; Roussel, Sophie (2022)
    Listeria monocytogenes (Lm) is a ubiquitous bacterium that causes listeriosis, a serious foodborne illness. In the nature-to-human transmission route, Lm can prosper in various ecological niches. Soil and decaying organic matter are its primary reservoirs. Certain clonal complexes (CCs) are over-represented in food production and represent a challenge to food safety. To gain new understanding of Lm adaptation mechanisms in food, the genetic background of strains found in animals and environment should be investigated in comparison to that of food strains. Twenty-one partners, including food, environment, veterinary and public health laboratories, constructed a dataset of 1484 genomes originating from Lm strains collected in 19 European countries. This dataset encompasses a large number of CCs occurring worldwide, covers many diverse habitats and is balanced between ecological compartments and geographic regions. The dataset presented here will contribute to improve our understanding of Lm ecology and should aid in the surveillance of Lm. This dataset provides a basis for the discovery of the genetic traits underlying Lm adaptation to different ecological niches.
  • Cockell, Charles S.; Harrison, Jesse P.; Stevens, Adam H.; Payler, Samuel J.; Hughes, Scott S.; Nawotniak, Shannon E. Kobs; Brady, Allyson L.; Elphic, R. C.; Haberle, Christopher W.; Sehlke, Alexander; Beaton, Kara H.; Abercromby, Andrew F. J.; Schwendner, Petra; Wadsworth, Jennifer; Landenmark, Hanna; Cane, Rosie; Dickinson, Andrew W.; Nicholson, Natasha; Perera, Liam; Lim, Darlene S. S. (2019)
    A major objective in the exploration of Mars is to test the hypothesis that the planet hosted life. Even in the absence of life, the mapping of habitable and uninhabitable environments is an essential task in developing a complete understanding of the geological and aqueous history of Mars and, as a consequence, understanding what factors caused Earth to take a different trajectory of biological potential. We carried out the aseptic collection of samples and comparison of the bacterial and archaeal communities associated with basaltic fumaroles and rocks of varying weathering states in Hawai'i to test four hypotheses concerning the diversity of life in these environments. Using high-throughput sequencing, we found that all these materials are inhabited by a low-diversity biota. Multivariate analyses of bacterial community data showed a clear separation between sites that have active fumaroles and other sites that comprised relict fumaroles, unaltered, and syn-emplacement basalts. Contrary to our hypothesis that high water flow environments, such as fumaroles with active mineral leaching, would be sites of high biological diversity, alpha diversity was lower in active fumaroles compared to relict or nonfumarolic sites, potentially due to high-temperature constraints on microbial diversity in fumarolic sites. A comparison of these data with communities inhabiting unaltered and weathered basaltic rocks in Idaho suggests that bacterial taxon composition of basaltic materials varies between sites, although the archaeal communities were similar in Hawai'i and Idaho. The taxa present in both sites suggest that most of them obtain organic carbon compounds from the atmosphere and from phototrophs and that some of them, including archaeal taxa, cycle fixed nitrogen. The low diversity shows that, on Earth, extreme basaltic terrains are environments on the edge of sustaining life with implications for the biological potential of similar environments on Mars and their exploration by robots and humans.
  • Baltrenaite, Edita; Baltrenas, Pranas; Bhatnagar, Amit; Vilppo, Teemu; Selenius, Mikko; Koistinen, Arto; Dahl, Mari; Penttinen, Olli-Pekka (2017)
    The environmental legislation and strict enforcement of environmental regulations are the tools effectively used for developing the market of materials for environmental protection technologies. Sustain ability criteria shift environmental engineering systems to more sustainable-material-based technologies. For carbon-based medium materials in biofiltration, this trend results in attempts to use biochar for biofiltration purposes. The paper presents the analysis of biochar properties based on the main criteria for biofiltration medium integrating the environmental quality properties of biochar, following the European Biochar Certificate guidelines. Three types of biochar produced from feedstock of highly popular and abundant types of waste are analysed. A multi component approach was applied to summarize the results. The lignocellulosic type of biochar was found to be more competitive for use as a biofiltration medium than the types of biochar with high ash or lignin content. (C) 2016 Elsevier Ltd. All rights reserved.
  • Torresan, Chiara; Benito Garzón, Marta; O’Grady, Michael; Robson, Thomas Matthew; Picchi, Gianni; Panzacchi, Pietro; Tomelleri, Enrico; Smith, Melanie; Marshall, John; Wingate, Lisa; Tognetti, Roberto; Rustad, Lindsey E.; Kneeshaw, Dan (2021)
    Climate-smart forestry (CSF) is an emerging branch of sustainable adaptive forest management aimed at enhancing the potential of forests to adapt to and mitigate climate change. It relies on much higher data requirements than traditional forestry. These data requirements can be met by new devices that support continuous, in situ monitoring of forest conditions in real time. We propose a comprehensive network of sensors, i.e., a wireless sensor network (WSN), that can be part of a worldwide network of interconnected uniquely addressable objects, an Internet of Things (IoT), which can make data available in near real time to multiple stakeholders, including scientists, foresters, and forest managers, and may partially motivate citizens to participate in big data collection. The use of in situ sources of monitoring data as ground-truthed training data for remotely sensed data can boost forest monitoring by increasing the spatial and temporal scales of the monitoring, leading to a better understanding of forest processes and potential threats. Here, some of the key developments and applications of these sensors are outlined, together with guidelines for data management. Examples are given of their deployment to detect early warning signals (EWS) of ecosystem regime shifts in terms of forest productivity, health, and biodiversity. Analysis of the strategic use of these tools highlights the opportunities for engaging citizens and forest managers in this new generation of forest monitoring.
  • Setälä, Heikki; Szlavecz, Katalin; Pullen, Jamie D.; Parker, John D.; Huang, Yumei; Chang, Chih-Han (2022)
    Acute resource pulses can have dramatic legacies for organismal growth, but the legacy effects of resource pulses on broader aspects of community structure and ecosystem processes are less understood. Mass emergence of periodical cicadas (Magicicada spp.) provides an excellent opportunity to shed light on the influence of resource pulses on community and ecosystem dynamics: the adults emerge every 13 or 17 years in vast numbers over much of eastern North America, with a smaller but still significant number becoming incorporated into forest food webs. To study the potential effects of such arthropod resource pulse on primary production and belowground food webs, we added adult cicada bodies to the soil surface surrounding sycamore trees and assessed soil carbon and nitrogen concentrations, plant-available nutrients, abundance and community composition of soil fauna occupying various trophic levels, decomposition rate of plant litter after 50 and 100 days, and tree performance for 4 years. Contrary to previous studies, we did not find significant cicada effects on tree performance despite observing higher plant-available nutrient levels on cicada addition plots. Cicada addition did change the community composition of soil nematodes and increased the abundance of bacterial- and fungal-feeding nematodes, while plant feeders, omnivores, and predators were not influenced. Altogether, acute resource pulses from decomposing cicadas propagated belowground to soil microbial-feeding invertebrates and stimulated nutrient mineralization in the soil, but these effects did not transfer up to affect tree performance. We conclude that, despite their influence on soil food web and processes they carry out, even massive resource pulses from arthropods do not necessarily translate to NPP, supporting the view that ephemeral nutrient pulses can be attenuated relatively quickly despite being relatively large in magnitude.
  • Zhang-Turpeinen, Huizhong; Kivimäenpää, Minna; Berninger, Frank; Köster, Kajar; Zhao, Peng; Zhou, Xuan; Pumpanen, Jukka (2021)
    The amplification of global warming in the Northern regions results in a higher probability of wildfires in boreal forests. On the forest floor, wildfires have long-term effects on vegetation composition as well as soil and its microbial communities. A large variety of biogenic volatile organic compounds (BVOCs) such as isoprene, monoterpenes, sesquiterpenes have been observed to be emitted from soil and understory vegetation of boreal forest floor. Ultimately, the fire-induced changes in the forest floor affect its BVOC fluxes, and the recovery of the forest floor determines the quantity and quality of BVOC fluxes. However, the effects of wildfires on forest floor BVOC fluxes are rarely studied. Here we conducted a study of the impacts of post-fire succession on forest floor BVOC fluxes along a 158-year fire chronosequence in boreal Scots pine stands near the northern timberline in north-eastern Finland throughout a growing season. We determined the forest floor BVOC fluxes and investigated how the environmental and ground vegetation characteristics, soil respiration rates, and soil microbial and fungal biomass are associated with the BVOC fluxes during the post-fire succession. The forest floor was a source of diverse BVOCs. Monoterpenes (MTs) were the largest group of emitted BVOCs. We observed forest age-related differences in the forest floor BVOC fluxes along the fire chronosequence. The forest floor BVOC fluxes decreased with the reduction in ground vegetation coverage resulted from wildfire, and the decreased fluxes were also connected to a decrease in microbial activity as a result of the loss of plant roots and soil organic matter. The increase in BVOC fluxes was associated with the recovery of aboveground plant coverage and soils. Our results suggested taking into consideration the implications of BVOC flux variations on the atmospheric chemistry and climate feedbacks.
  • Hagner, Marleena; Uusitalo, Marja; Ruhanen, Hanna; Heiskanen, Juha; Peltola, Rainer; Tiilikkala, Kari; Hyvonen, Juha; Sarala, Pertti; Makitalo, Kari (2021)
    In the northern boreal zone, revegetation and landscaping of closed mine tailings are challenging due to the high concentrations of potentially toxic elements; the use of nutrient-poor, glacigenic cover material (till); cool temperatures; and short growing period. Recycled waste materials such as biochar (BC) and composted sewage sludge (CSS) have been suggested to improve soil forming process and revegetation success as well as decrease metal bioavailability in closed mine tailing areas. We conducted two field experiments in old iron mine tailings at Rautuvaara, northern Finland, where the native mine soil or transported cover till soil had not supported plant growth since the mining ended in 1989. The impacts of CSS and spruce (Picea abies)-derived BC application to till soil on the survival and growth of selected plant species (Pinus sylvestris, Salix myrsinifolia, and grass mixture containing Festuca rubra, Lolium perenne, and Trifolium repens) were investigated during two growing seasons. In addition, the potential of BC to reduce bioaccumulation of metals in plants was studied. We found that (1) organic amendment like CSS markedly enhanced the plant growth and is therefore needed for vegetation establishment in tailing sites that contained only transported till cover, and (2) BC application to till soil-CSS mixture further facilitated the success of grass mixtures resulting in 71-250% higher plant biomass. On the other hand, (3) no effects on P. sylvestris or S. myrsinifolia were recorded during the first growing seasons, and (4) accumulation of metals in cover plants was negligible and BC application to till further decreased the accumulation of Al, Cr, and Fe in the plant tissues.
  • Rehman, Sidra; Mansoora, Nida; Al-Dhumri, Sami A.; Amjad, Syeda F.; Al-Shammari, Wasimah B.; Almutari, Mohammad M.; Alhusayni, Fatimah S.; Al Bakre, Dhafer A.; Lalarukh, Irfana; Alshahri, Abdullah H.; Poczai, Peter; Galal, Tarek M.; Abdelhafez, Ahmed A. (2022)
    Heavy metal stress and less nutrient availability are some of the major concerns in agriculture. Both abiotic stresses have potential to decrease the crops productivity. On the other hand, organic fertilizers i.e., activated carbon biochar (ACB) and arbuscular mycorrhizal fungi (AMF) increase nutritional and heavy metal like Nickel (Ni) stress tolerance and provide immunity to plants for their survival in unfavorable environments. Previous studies have only looked at single applications of either ACB or AMF thus far. There is limited evidence of their synergistic effects, especially in plants growing in soil contaminated with nickel (Ni). To cover the knowledge gap of combined use of AMF inoculation (Glomus intraradices) and/or wheat straw biochar amendments on wheat growth, antioxidant activities and osmolytes concentration, present study is conducted. The use of either the AMF inoculant or the ACB alone resulted in improved wheat growth and decreased Ni uptake. Furthermore, sole AMF or ACB also reduced Ni stress effectively, allowing wheat to grow faster and reducing soil Ni transfer into plant tissue. In comparison to a control, adding ACB with AMF inoculant considerably increased fungal populations. The most significant increase in wheat growth and decrease in tissue Ni contents came from amending soil with AMF inoculant and biochar. Inducing soil alkalinization and causing Ni immobilization, as well as decreasing Ni phyto-availability, the combination treatment had a synergistic impact. These findings imply that AMF inoculation in ACB treatment could be used not only for wheat production but also for Ni-contaminated soil phyto-stabilization. (C) 2022 The Author(s). Published by Elsevier B.V.
  • Ren, Wenzi; Penttilä, Reijo; Kasanen, Risto; Asiegbu, Fred (2022)
    The microbiome of Heterobasidion-induced wood decay of living trees has been previously studied; however, less is known about the bacteria biota of its perennial fruiting body and the adhering wood tissue. In this study, we investigated the bacteria biota of the Heterobasidion fruiting body and its adhering deadwood. Out of 7,462 operational taxonomic units (OTUs), about 5,918 OTUs were obtained from the fruiting body and 5,469 OTUs were obtained from the associated dead wood. Interestingly, an average of 52.6% of bacteria biota in the fruiting body was shared with the associated dead wood. The overall and unique OTUs had trends of decreasing from decay classes 1 to 3 but increasing in decay class 4. The fruiting body had the highest overall and unique OTUs number in the fourth decay class, whereas wood had the highest OTU in decay class 1. Sphingomonas spp. was significantly higher in the fruiting body, and phylum Firmicutes was more dominant in wood tissue. The FAPROTAX functional structure analysis revealed nutrition, energy, degradation, and plant-pathogen-related functions of the communities. Our results also showed that bacteria communities in both substrates experienced a process of a new community reconstruction through the various decay stages. The process was not synchronic in the two substrates, but the community structures and functions were well-differentiated in the final decay class. The bacteria community was highly dynamic; the microbiota activeness, community stability, and functions changed with the decay process. The third decay class was an important turning point for community restructuring. Host properties, environmental factors, and microbial interactions jointly influenced the final community structure. Bacteria community in the fruiting body attached to the living standing tree was suppressed compared with those associated with dead wood. Bacteria appear to spread from wood tissue of the standing living tree to the fruiting body, but after the tree is killed, bacteria moved from fruiting body to wood. It is most likely that some of the resident endophytic bacteria within the fruiting body are either parasitic, depending on it for their nutrition, or are mutualistic symbionts.
  • Ma, Yang; Qu, Zhao-Lei; Liu, Bing; Tan, Jia-Jin; Asiegbu, Fred O.; Sun, Hui (2020)
    Pine wilt disease (PWD) caused by the nematode Bursaphelenchus xylophilus is a devastating disease in conifer forests in Eurasia. However, information on the effect of PWD on the host microbial community is limited. In this study, the bacterial community structure and potential function in the needles, roots, and soil of diseased pine were studied under field conditions using Illumina MiSeq coupled with Phylogenetic Investigation of Communities by Reconstruction of Unobserved states (PICRUSt) software. The results showed that the community and functional structure of healthy and diseased trees differed only in the roots and needles, respectively (p <0.05). The needles, roots, and soil formed unique bacterial community and functional structures. The abundant phyla across all samples were Proteobacteria (41.9% of total sequence), Actinobacteria (29.0%), Acidobacteria (12.2%), Bacteroidetes (4.8%), and Planctomycetes (2.1%). The bacterial community in the healthy roots was dominated by Acidobacteria, Planctomycetes, and Rhizobiales, whereas in the diseased roots, Proteobacteria, Firmicutes, and Burkholderiales were dominant. Functionally, groups involved in the cell process and genetic information processing had a higher abundance in the diseased needles, which contributed to the difference in functional structure. The results indicate that PWD can only affect the host bacteria community structure and function in certain anatomical regions of the host tree.
  • Vaario, Lu-Min; Asamizu, Shumpei; Sarjala, Tytti; Matsushita, Norihisa; Onaka, Hiroyasu; Xia, Yan; Kurokochi, Hiroyuki; Morinaga, Shin-Ichi; Huang, Jian; Zhang, Shijie; Lian, Chunlan (2020)
    Tricholoma matsutake is known to be the dominant fungal species in matsutake fruitbody neighboring (shiro) soil. To understand the mechanisms behind matsutake dominance, we studied the bacterial communities in matsutake dominant shiro soil and non-shiro soil, isolated the strains of Streptomyces from matsutake mycorrhizal root tips both from shiro soil and from the Pinus densiflora seedlings cultivated in shiro soil. Further, we investigated three Streptomyces spp. for their ability to inhibit fungal growth and Pinus densiflora seedling root elongation as well as two strains for their antifungal and antioxidative properties. Our results showed that Actinobacteria was the most abundant phylum in shiro soil. However, the differences in the Actinobacterial community composition (phylum or order level) between shiro and non-shiro soils were not significant, as indicated by PERMANOVA analyses. A genus belonging to Actinobacteria, Streptomyces, was present on the matsutake mycorrhizas, although in minority. The two antifungal assays revealed that the broths of three Streptomyces spp. had either inhibitory, neutral or promoting effects on the growth of different forest soil fungi as well as on the root elongation of the seedlings. The extracts of two strains, including one isolated from the P. densiflora seedlings, inhibited the growth of either pathogenic or ectomycorrhizal fungi. The effect depended on the medium used to cultivate the strains, but not the solvent used for the extraction. Two Streptomyces spp. showed antioxidant activity in one out of three assays used, in a ferric reducing antioxidant power assay. The observed properties seem to have several functions in matsutake shiro soil and they may contribute to the protection of the shiro area for T. matsutake dominance.
  • Kang, Zongjing; Li, Xiaolin; Li, Yan; Ye, Lei; Zhang, Bo; Zhang, Xiaoping; Penttinen, Petri; Gu, Yunfu (2022)
    Truffles (Tuber spp.) are edible ectomycorrhizal fungi with high economic value. Bacteria in ectomycorrhizosphere soils are considered to be associated with the nutrient uptake of truffles and hosts. Whether Tuber spp. inoculation can affect the growth of Quercus aliena, the ectomycorrhizosphere soil, and the rhizosphere nirK and nirS-denitrifier communities at the ectomycorrhizae formation stage is still unclear. Therefore, we inoculated Q. aliena with the black truffles Tuber melanosporum and Tuber indicum, determined the physiological activity and morphological indices of Q. aliena seedlings, analyzed the physicochemical properties of ectomycorrhizosphere soils, and applied DNA sequencing to assess the nirK and nirS- denitrifier community structure in ectomycorrhizosphere soils. Peroxidase activity was higher in the seedlings inoculated with T. melanosporum than in the T. indicum inoculation and uninoculated control treatments. The available phosphorus contents were lower and nitrate contents were higher in those with truffle inoculation, and T. melanosporum treatment differed more from the control than the T. indicum treatment. The richness of the nirK-community was highest in the T. indicum treatment and lowest in the uninoculated treatment. The differences in nirK-community composition across treatments were not statistically significant, but the nirS communities were different. The nirS-type bacteria correlated with three environmental factors (pH, available phosphorus, and nitrate contents), whereas the nirK-type bacteria were only associated with the nitrate contents. Generally, this work revealed that inoculation with Tuber spp. would change a few nutrient contents and richness of nirK-type bacteria and had little effects on growth of Q. aliena seedlings in the initial stage of inoculation. The results of this study may provide in-depth insights into the relationships between Tuber spp. and hosts, which should be taken into account when developing truffle production methods.
  • Lucke, Bernhard; Roskin, Joel; Vanselow, Kim André; Bruins, Hendrik; Abu-Jaber, Nizar; Deckers, Katleen; Lindauer, Susanne; Porat, Naomi; Reimer, Paula J.; Bäumler, Rupert; Erickson-Gini, Tali; Kouki, Paula (2019)
    Loess accumulated in the Negev desert during the Pleistocene and primary and secondary loess remains cover large parts of the landscape. Holocene loess deposits are however absent. This could be due low accumulation rates, lack of preservation, and higher erosion rates in comparison to the Pleistocene. This study hypothesized that archaeological ruins preserve Holocene dust. We studied soils developed on archaeological hilltop ruins in the Negev and the Petra region and compared them with local soils, paleosols, geological outcrops, and current dust. Seven statistically modeled grain size end-members were identified and demonstrate that the ruin soils in both regions consist of mixtures of local and remote sediment sources that differ from dust compositions deposited during current storms. This discrepancy is attributed to fixation processes connected with sediment-fixing agents such as vegetation, biocrusts, and/or clast pavements associated with vesicular layers. Average dust accretion rates in the ruins are estimated to be similar to 0.14 mm/a, suggesting that similar to 30% of the current dust that can be trapped with dry marble dust collectors has been stored in the ruin soils. Deposition amounts and grain sizes do not significantly correlate with wind intensity. However, precipitation may have contributed to dust accretion. A snowstorm in the Petra region delivered a significantly higher amount of sediment than rain or dry deposition. Snowfall dust had a unique particle size distribution relatively similar to the ruin soils. Wet deposition and snow might catalyze dust deposition and enhance fixation by fostering vegetation and crust formation. More frequent snowfall during the Pleistocene may have been an important mechanism of primary loess deposition in the southern Levant.
  • Räsänen, Aleksi; Juutinen, Sari; Tuittila, Eeva-Stiina; Aurela, Mika; Virtanen, Tarmo (2019)
  • Autio, Antti; Johansson, Tino; Motaroki, Lilian; Minoia, Paola; Pellikka, Petri (2021)
    CONTEXT: Climate uncertainty challenges the livelihoods of smallholder farmers in sub-Saharan Africa. Awareness of climate-smart agricultural (CSA) practices and access to climate-smart technologies are key factors in determining the utilization of farm and land management practices that may simultaneously decrease greenhouse gas emissions, increase the adaptive capacity of farmers, and improve food security. OBJECTIVE: Understanding how biophysical and socio-economic constraints affect the adoption of CSA practices and technologies plays an essential role in policy and intervention planning. Our objective was to identify these constraints among smallholder farmers in Taita Taveta County of Southeast Kenya across varying agro-ecological zones. METHODS: We conducted a Climate-Smart Agriculture Rapid Appraisal that consisted of four mostly genderdisaggregated smallholder farmer workshops (102 participants), a household survey (65 participants), key informant interviews (16 informants), and four transect walks. RESULTS AND CONCLUSIONS: Our results indicate a dissonance in the perceived awareness of CSA practices and utilization of CSA technologies between state actors and farmers. State actors emphasize lack of awareness as a barrier to adoption, while farmers express knowledgeability regarding environmental change and climate-smart practices but are confined by limitations and restrictions posed by e.g. market mechanisms, land tenure issues,and lack of resources. These restrictions include e.g. uncertainty in product prices, lack of land ownership, scarcity of arable land, and simply lack of capital or willingness to invest. Farmers are further challenged by the emergence of new pests and human-wildlife conflicts. Our research findings are based on the contextual settings of Taita Taveta County, but the results indicate that adopting CSA practices and utilizing technologies, especially in sub-Saharan regions that are heavily based on subsistence agriculture with heterogenous agro-ecological zones, require localized and gender-responsive solutions in policy formation and planning of both agricultural extension services and development interventions that take into account the agency of the farmers. SIGNIFICANCE: This study contributes to existing climate change adaptation research by increasing our un- derstanding of how physical and socio-economic constraints can affect the adoption of new farm and land management practices, and how CSA-based intervention strategies could be restructured by local stakeholders to be more inclusive.
  • Köster, Kajar; Köster, Egle; Berninger, Frank; Heinonsalo, Jussi; Pumpanen, Jukka (2018)
    Reindeer (Rangifer tarandus L.) is considered to be an important mammalian herbivore, strongly influencing Arctic lichen-dominated ecosystems. There is no wide knowledge about the effect of reindeer on greenhouse gas (GHG) fluxes in northern boreal forests. Ground vegetation plays an important role in absorbing nitrogen (N) and carbon dioxide (CO2) from the atmosphere. Lately, it has also been found to be a significant source of nitrous oxide (N2O) and a small source of methane (CH4). We investigated the influence of reindeer grazing on field layer GHG (CO2, CH4, and N2O) fluxes, ground vegetation coverage and biomass, and soil physical properties (temperature and moisture) in a northern boreal forest. At our study site, the reindeer-induced replacement of lichen by mosses had contrasting effects on the GHG fluxes originating from the field layer. Field layer CO2 efflux was significantly higher in grazed areas. The field layer was a CH4 sink in all areas, but grazed areas absorbed more CH4 compared to non-grazed areas. Although total N2O fluxes remained around 0 in grazed areas, a small N2O sink occurred in non-grazed areas with lower moss biomass. Our results indicated that grazing by reindeer in northern boreal forests affects GHG fluxes from the forest field layer both positively and negatively, and these emissions largely depend on grazing-induced changes in vegetation composition.
  • Epie, Kenedy E.; Artigas, Olga M.; Santanen, Arja; Mäkelä, Pirjo S. A.; Stoddard, Frederick L. (2018)
    The biomass potential of eight high yielding maize cultivars was studied in the sub-boreal climate of southern Finland. The effects of harvest date on lignin and sugar production, biomass yield, mineral element composition, bioenergy potential and soil nutrient management were determined in two years. The eight maize cultivars produced 17.6-33.3 t ha(-1) of biomass. The ear fraction contained 50-60% of the biomass, and ash and mineral element composition of the plant fractions were significantly different (p <0.001), with more ash, Ca and S in the above-ear fractions of the plants than in the mid-stalk portions, whereas the C:N ratio was highest in the lower stalk. Cultivars with less lignin content produced more fermetable sugars. Despite the relatively cool growing conditions and short season of the sub-boreal region, maize has potential for use as biomass, for biofuel or other uses. The crop can be fractioned into ear and stalk, with the lower 20 cm of stalk left in the field to maintain soil organic matter content.
  • Saine, Sonja; Ovaskainen, Otso; Somervuo, Panu; Abrego, Nerea (2020)
    Inferring interspecific interactions indirectly from community data is of central interest in community ecology. Data on species communities can be surveyed using different methods, each of which may differ in the amount and type of species detected, and thus produce varying information on interaction networks. Since fruit bodies reflect only a fraction of the wood-inhabiting fungal diversity, there is an ongoing debate in fungal ecology on whether fruit body?based surveys are a valid method for studying fungal community dynamics compared to surveys based on DNA metabarcoding. In this paper, we focus on species-to-species associations and ask whether the associations inferred from data collected by fruit-body surveys reflect the ones found from data collected by DNA-based surveys. We estimate and compare the association networks resulting from different survey methods using a joint species distribution model. We recorded both raw and residual associations that respectively do not and do correct for the influence of the abiotic predictors when estimating the species-to-species associations. The analyses of the DNA data yielded a larger number of species-to-species associations than the analyses of the fruit body?based data as expected. Yet, we estimated unique associations also from the fruit-body data. Our results show that the directions of estimated residual associations were consistent between the data types, whereas the raw associations were much less consistent, highlighting the need to account for the influence of relevant environmental covariates when estimating association networks. We conclude that even though DNA-based survey methods are more informative about the total number of interacting species, fruit-body surveys are also an adequate method for inferring association networks in wood-inhabiting fungi. Since the DNA and fruit-body data carry on complementary information on fungal communities, the most comprehensive insights are obtained by combining the two survey methods. This article is protected by copyright. All rights reserved.
  • Moose, Ryan A.; Schigel, Dmitry; Kirby, Lucas J.; Shumskaya, Maria (2019)
    Saproxylic fungi act as keystone species in forest ecosystems because they colonise and decompose dead wood, facilitating colonisation by later species. Here, we review the importance of intact forest ecosystems to dead wood fungi, as well as trends in their diversity research and challenges in conservation. Saproxylic communities are sensitive to transition from virgin forests to managed ecosystems, since the latter often results in reduced tree diversity and the removal of their natural habitat dead wood. The impact of dead wood management can be quite significant since many saproxylic fungi are host-specific. The significance of citizen science and educational programmes for saproxylic mycology is discussed with the emphasis on the North American region. We intend to raise the awareness of the role that dead wood fungi play in forest health in order to support development of corresponding conservational programmes.
  • Mali, Tuulia; Mäki, Mari; Hellén, Heidi; Heinonsalo, Jussi; Bäck, Jaana; Lundell, Taina (2019)
    Effect of three wood-decaying fungi on decomposition of spruce wood was studied in solid-state cultivation conditions for a period of three months. Two white rot species (Trichaptum abietinum and Phlebia radiata) were challenged by a brown rot species (Fomitopsis pinicola) in varying combinations. Wood decomposition patterns as determined by mass loss, carbon to nitrogen ratio, accumulation of dissolved sugars, and release of volatile organic compounds (VOCs) were observed to depend on both fungal combinations and growth time. Similar dependence of fungal species combination, either white or brown rot dominated, was observed for secreted enzyme activities on spruce wood. Fenton chemistry suggesting reduction of Fe3+ to Fe2+ was detected in the presence of F. pinicola, even in co-cultures, together with substantial degradation of wood carbohydrates and accumulation of oxalic acid. Significant correlation was perceived with two enzyme activity patterns (oxidoreductases produced by white rot fungi; hydrolytic enzymes produced by the brown rot fungus) and wood degradation efficiency. Moreover, emission of four signature VOCs clearly grouped the fungal combinations. Our results indicate that fungal decay type, either brown or white rot, determines the loss of wood mass and decomposition of polysaccharides as well as the pattern of VOCs released upon fungal growth on spruce wood.