Search results for "Tundra"
showing 10 items of 30 documents
Plant trait‐environment relationships in tundra are consistent across spatial scales
2023
Patterns and processes shaping ecosystems vary across spatiotemporal scales. As plant functional traits reflect ecosystem properties, investigating their relationships with environment provides an important tool to understand and predict ecosystem structure and functioning. This is particularly important in the tundra where a changing climate may trigger severe alterations in plant communities as both summer and winter conditions are changing. Here, we investigate the relationships between key environmental drivers including summer temperature, snow persistence, topographic position and soil pH, and species height, specific leaf area (SLA) and seed mass as plant traits. The study is carried…
Statistical upscaling of ecosystem CO2 fluxes across the terrestrial tundra and boreal domain: Regional patterns and uncertainties
2021
The regional variability in tundra and boreal carbon dioxide (CO2) fluxes can be high, complicating efforts to quantify sink-source patterns across the entire region. Statistical models are increasingly used to predict (i.e., upscale) CO2 fluxes across large spatial domains, but the reliability of different modeling techniques, each with different specifications and assumptions, has not been assessed in detail. Here, we compile eddy covariance and chamber measurements of annual and growing season CO2 fluxes of gross primary productivity (GPP), ecosystem respiration (ER), and net ecosystem exchange (NEE) during 1990–2015 from 148 terrestrial high-latitude (i.e., tundra and boreal) sites to a…
The ABCflux database: Arctic-boreal CO2flux observations and ancillary information aggregated to monthly time steps across terrestrial ecosystems
2022
Past efforts to synthesize and quantify the magnitude and change in carbon dioxide (CO2) fluxes in terrestrial ecosystems across the rapidly warming Arctic–boreal zone (ABZ) have provided valuable information but were limited in their geographical and temporal coverage. Furthermore, these efforts have been based on data aggregated over varying time periods, often with only minimal site ancillary data, thus limiting their potential to be used in large-scale carbon budget assessments. To bridge these gaps, we developed a standardized monthly database of Arctic–boreal CO2 fluxes (ABCflux) that aggregates in situ measurements of terrestrial net ecosystem CO2 exchange and its derived partitioned…
Sources of nitrous oxide and the fate of mineral nitrogen in subarctic permafrost peat soils
2022
Nitrous oxide (N2O) emissions from permafrost-affected terrestrial ecosystems have received little attention, largely because they have been thought to be negligible. Recent studies, however, have shown that there are habitats in the subarctic tundra emitting N2O at high rates, such as bare peat (BP) surfaces on permafrost peatlands. Nevertheless, the processes behind N2O production in these high-emission habitats are poorly understood. In this study, we established an in situ 15N-labeling experiment with two main objectives: (1) to partition the microbial sources of N2O emitted from BP surfaces on permafrost peatlands and (2) to study the fate of ammonium and nitrate in these soils and in …
Data from: Grazing decreases N partitioning among coexisting plant species
2018
1. Herbivores play a key role in shaping ecosystem structure and functions by influencing plant and microbial community composition and nutrient cycling. 2. This study investigated the long-term effects of herbivores on plant resource acquisition. We explored differences in the natural δ15N signatures in plant, microbial and soil N pools, and examined mycorrhizal colonization in two tundra sites that have been either lightly or heavily grazed by reindeer for more than 50 years. The study examined changes in nutrient acquisition in five common tundra plants with contrasting traits and mycorrhiza status; the mycorrhizal dwarf shrubs, Betula nana, Vaccinium myrtillus and Empetrum hermaphroditu…
Setaria tundra, what do we know, what is still to be discovered?
2021
Over the past years, the nematode species from the Onchocercidae family, Setaria tundra, has expanded its range by thousands of kilometres from subpolar to subtropical climate zone. Its presence has been confirmed in seven new countries. The appearance of this parasite in many other European countries, especially central and southern ones, is highly probable. In recent years, its mass appearance has led to the numerous fall of reindeer in Fennoscandia, thus causing significant economic damage. There is also a growing risk of its gradation in Central Europe, which threatens overpopulated wild deer species and possibly farm animals, however there is no information if other than mosquitoes blo…
Grazing intensity in subarctic tundra affects the temperature adaptation of soil microbial communities
2015
Abstract Grazing by large ungulates, such as reindeer (Rangifer tarandus L.), in subarctic tundra exerts a considerable effect on the soil microclimate. Because of higher insulation by the aboveground vegetation in light versus heavily grazed areas, soil temperatures during the growing season are considerably higher under heavy grazing. Here, we hypothesized that these grazer-induced changes in soil microclimate affect the temperature sensitivity of soil microbial activity. To test this hypothesis, we conducted soil incubations at different temperatures (4 °C, 9 °C and 14 °C) for six weeks using soils from sites with contrasting long-term grazing intensities. Microbial respiration at low te…
Benthic mats offer a potential subsidy to pelagic consumers in tundra pond food webs
2014
We quantified the potential nutritional contribution of benthic mats to pelagic consumers in tundra ponds using three approaches. (1) We compared benthic and pelagic habitats based on their algal biomass and community composition and assessed the dietary quality in terms of fatty acid (FA) concentrations in both habitats. The algal community compositions differed significantly between habitats. Both benthic and pelagic habitats contained saturated and unsaturated FAs, but on average there were more FAs relative to carbon in the pelagic habitat (44 6 29 mg mg C21) than the benthic habitat (23 6 18 mg mg C21) across all studied ponds. (2) We quantified the contribution of benthic mats to the …
In-depth characterization of denitrifier communities across different soil ecosystems in the tundra
2022
Abstract Background In contrast to earlier assumptions, there is now mounting evidence for the role of tundra soils as important sources of the greenhouse gas nitrous oxide (N2O). However, the microorganisms involved in the cycling of N2O in this system remain largely uncharacterized. Since tundra soils are variable sources and sinks of N2O, we aimed at investigating differences in community structure across different soil ecosystems in the tundra. Results We analysed 1.4 Tb of metagenomic data from soils in northern Finland covering a range of ecosystems from dry upland soils to water-logged fens and obtained 796 manually binned and curated metagenome-assembled genomes (MAGs). We then sear…
Porolaidunnuksen vaikutus sammalten monimuotoisuuteen tuottavilla ja vähätuottoisilla tuntureilla pohjoisessa Fennoskandiassa
2010
Laiduntajat vaikuttavat kasvillisuuteen useilla sekä suorilla että epäsuorilla mekanismeilla, joista epäsuorat voivat olla ekosysteemiprosessien kannalta tärkeämpiä. Vähätuottoisella tundralla kasvinsyöjien vaikutuksen kasvillisuuteen tiedetään olevan merkittävä, mutta suuri osa tutkimuksesta on keskittynyt laiduntajien ravintokasveihin. Tundralla sammalet muodostavat suuren osan kasviyhteisöjen biomassasta ja monimuotoisuudesta, ja niiden on havaittu toimivan laiduntajien vaikutusten välittäjinä muuhun kasvillisuuteen ja maaperään. Laidunnuksen vaikutuksia sammalyhteisöihin on kuitenkin tutkittu hyvin vähän. Tässä tutkimuksessa selvitettiin poron (Rangifer tarandus tarandus L.) laidunnukse…