Peter Schlyter

The chemical weathering regime of Kärkevagge, arctic–alpine Sweden

Abstract Karkevagge is a valley located in Swedish Lapland at approximately 68°N and represents an arctic–alpine landscape. It is a presently periglacial, glaciated trough incised into essentially horizontal metamorphic rocks, some of which are presumably pyrite-rich. A set of coordinated studies was undertaken to investigate the nature of chemical weathering and pedogenesis in the valley and upon the abutting ridges. August 1996 water quality measures reveal considerable spatial variation in solute totals with the highest Total Dissolved Solute abundances being correlated with high sulfate abundances. Ridge-crest soils exhibited poor horizonation, but more extensive development of secondary clay minerals developed in situ than was found in valley-flank and valley-bottom soils. Valley soils exhibited multiple thin horizons, many of which were buried, and are taken to reflect great paraglacial and periglacial instability. Favorable microenvironments in the valley permit significant development of Spodosols. Coarse debris along and across the valley bears both weathering rinds and rock coatings. Rock coatings in the valley include several types of iron films, sulfate crusts, carbonate skins, and heavy metal skins. Karkevagge represents a mild arctic environment, which does not preclude substantial chemical weathering in locations where abundant pyrite-rich bedrock and water coincide. This weathering follows pathways which are eminently expectable given that weathering of the pyrite-rich rock permits generation of sulfuric acid which, in turn, weathers muscovite mica and calcite in local schists and marble, respectively. Zones of intense chemical weathering also generate clearly visible deposits of gypsum and iron sulfate deposits such as jarosite. Not all arctic and/or alpine environments are likely to be so active chemically, but the results from Karkevagge clearly show that dismissal of chemical weathering in cold regions on the basis of presumed first principles is erroneous. Consequently, chemical weathering in such environments merits substantially more attention than it has hitherto received.

Solving problems in social–ecological systems : definition, practice and barriers of transdisciplinary research

Translating policies about sustainable development as a social process and sustainability outcomes into the real world of social–ecological systems involves several challenges. Hence, research policies advocate improved innovative problem-solving capacity. One approach is transdisciplinary research that integrates research disciplines, as well as researchers and practitioners. Drawing upon 14 experiences of problem-solving, we used group modeling to map perceived barriers and bridges for researchers’ and practitioners’ joint knowledge production and learning towards transdisciplinary research. The analysis indicated that the transdisciplinary research process is influenced by (1) the amount of traditional disciplinary formal and informal control, (2) adaptation of project applications to fill the transdisciplinary research agenda, (3) stakeholder participation, and (4) functional team building/development based on self-reflection and experienced leadership. Focusing on implementation of green infrastructure policy as a common denominator for the delivery of ecosystem services and human well-being, we discuss how to diagnose social–ecological systems, and use knowledge production and collaborative learning as treatments.

Clay mineralogy, chemical weathering and landscape evolution in Arctic–Alpine Sweden

Abstract The purpose of this research was to: (1) characterize the clay mineralogy of soils in and adjacent to Karkevagge, a recently deglaciated valley in Arctic Sweden, (2) document chemical weathering in a periglacial environment and (3) use the mineralogy to help explain landscape evolution. Soil samples were analyzed from 11 sites that differ in elevation, parent material, drainage, slope and vegetation. Parent materials include residuum, alluvium, colluvium and glaciofluvial material derived from garnet–mica–schist, plus, in one locality, a till of granitic origin. X-ray diffraction (XRD) was used to characterize the clay-size fraction (

Simulating Icelandic vegetation cover during the Holocene implications for long-term land degradation

We have simulated the spatial relationship between temperature change and long‐term potential vegetation cover dynamics. The results show that the potential vegetation and birch forest range is highly sensitive to the temperature conditions. Around 3000 BP the simulated potential vegetation cover began to decrease and at the time of the Viking settlement, in AD 874 (1076 BP), vegetation and forest cover was already in decline. The climate driven decline continued to an unprecedented low potential for vegetation for the Holocene that lasted c. 600 years, i.e. between ADc. 1300 and 1900. These interpretations are further supported by geomorphological and pollen data.

Relationship of Vegetation Distribution to Soil Properties in Kärkevagge, Swedish Lapland

Abstract Kärkevagge, an alpine ecosystem in the subarctic, has been the subject of scientific study for half a century. We investigated the relationship of its vegetation to soil properties. At the lowest elevations, on stable portions of the landscape dominated by Betula and Empetrum, are found Spodosols developed in glacio-fluvial sediments. Cryosaprists occur in scattered bedrock depressions with bog-type vegetation. Cryofluvents are found in flood-prone areas covered by dwarf-willow thickets. Intermediate elevations have meadow-type vegetation with Cryofluvents on floodplains and on lower colluvial slopes, Cryaquents in wetter areas, and Cryorthents on steeper soliflucted slopes. Above that, on steep, west-facing Dryas-covered colluvial slopes, soils are Ca-rich Eutrocryepts and Haplocryolls. The highest-elevation soils are infertile with poor horizonation, despite their possible antiquity, and vegetation that is largely cryptogams. Dystrocryepts occur on more stable alpine locations; Cryorthents on soliflucted areas; and Haploturbels, with shallow permafrost, above 1400 m. Measured annual soil temperatures range from +2.4°C at a Dryas site to −3.4°C at 1585 m at an alpine cryptogam site. Vegetation distribution in Kärkevagge is related to climatic factors, which are controlled by elevation and landscape position, and edaphic factors, which control soil moisture and nutrient availability.

Weathering rates of fine pebbles at the soil surface in Kärkevagge, Swedish Lapland

Abstract In 1994, nylon mesh bags containing ∼6.2-mm diameter fragments of either freshly crushed dolomite or granite were placed on meadow, solifluction meadow, birch, heath and alpine tundra vegetation that cover surfaces within Karkevagge, a glaciated arctic–alpine valley in Swedish Lapland. Each vegetation category contained three replicate sites comprising one bag of each rock type. In 1995, the study was extended to Dryas heath and willow (two sites only) surfaces. Percentage annual weight loss was used as a metric of chemical weathering rates. One site in each of the 1994 categories was measured in 1995. All sites were measured in 1999. Two dolomite and granite standards stored in the laboratory and subjected to identical cleaning and weighing regimes to the field samples, exhibited no more than a 0.24% total weight loss after 5 years. The percentage weight loss in the subgroup examined after 1 year (dolomite 0.54%/year; granite 0.41%/year) significantly exceeded the average annual loss for the subsequent 4 years in all cases (dolomite 0.40%/year; granite 0.07%/year). Ten sites with a 5-year record had a mean annual loss of 0.326±0.115%/year (two standard errors) for dolomite and 0.121±0.020%/year for granite. Assuming an exponential decay model, a 0.326%/year rate of loss produces a ‘half-life’ of approximately 212 years and a 0.121%/year loss rate, a half-life of approximately 570 years. Kruskal–Wallis one-way ANOVA on rank-ordered data determined significant differences in dolomite pebble mass loss between the Dryas heath and willow plus meadow microenvironments, as well as between the birch forest and the willow plus meadow microenvironments. The underpinning factor behind these differences appears to be moisture differences. A similar test failed to determine statistically significant differences for the granite pebbles. Dolomite appears to be a viable medium for determining mass loss rates over quite modest time periods providing that the number of samples is sufficiently large.

Paleo-Periglacial Ventifact Formation by Suspended Silt or Snow—Site Studies in South Sweden

Paleo-periglacial ventifacts are common in southern Sweden. Snow and/or silt abrasion have often been suggested as the agents for ventifact formation, owing to a comparative lack of eolian sands in...

Preliminary investigation of geochemical process responses to potential environmental change in Kärkevagge, Northern Scandinavia

Preliminary investigation of geochemical process responses to potential environmental change in Karkevagge, Northern Scandinavia

Comparison of radiocarbon dating of buried paleosols using arbuscular mycorrhizae spores and bulk soil samples.

Ten paleosols from four separate soil pits located in Kärkevagge, a glaciated trough in Swedish Lapland, were dated using radiocarbon. Each soil was dated using both conventional bulk soil organic material (SOM) and a pure sample of arbuscular mycorrhizae (AM) fungal spores. The latter are produced by ubiquitous mycorrhizal fungi associated with the roots of many plant genera and may be viewed as a fossil material that has not interacted with any soil constituent subsequent to its emplacement in the soil — at a time presumed to mark the cessation of a favorable soil-forming environment. Regional deglaciation is presumed to have been about 10 000 BP, while a cosmogenic exposure date obtained from the valley floor in Kärkevagge dated at 13 100 ± 1638 BP. The youngest paleosol, buried at ~6 cm in soil pit M3, produced a spore date of 0—281 cal. yr BP (1σ). However, bulk SOM dates of the same paleosol A horizon gave widely divergent dates and varied with the sample pretreatment, ie, the combustion temperature and the acid-base treatment. For example, the bulk SOM dates for that paleosol ranged from a post-bomb date of 0—314 cal. yr BP (1σ) to 2366—2710 cal. yr BP (1σ) when subjected to different pretreatments (acid only, acid-base-acid) and ignition temperatures (400, 800, or 900°C). The oldest paleosol in the set, buried at ~61 cm in soil pit M6, dated at 5479—5698 cal. yr BP (1σ) using spores, but beyond calibration using bulk SOM. The spore dates were all within the range to be expected of postglacial paleosols, but the bulk SOM dates were frequently beyond the generally accepted time of deglaciation. In addition, all of the spore dates followed a conventional age/depth pattern while the bulk SOM dates did not. There are known possible sources of geogenic carbon contamination in Kärkevagge which may well account for the obviously invalid older bulk SOM dates. An additional complication is that the spore dates vary somewhat with their density and diameter. However, where other types of fossil or charcoal are unavailable it appears that the enormously broad distribution of spores and their lack of interaction within the soil and persistence may well offer the prospect of an unusually useful radiocarbon dating medium within paleosols.

Biodiversity in sustainable forestry

The global and regional decline in biodiversity during modern times is the result of several interacting factors due to changes in human numbers, life styles, ways of land-use and production and the associated load of environmental pollution. Current risks of irreversible loss of habitats and extinction of species is incomparably greatest in species rich tropical areas of the developing South. Nevertheless, concerns for loss of local biodiversity also figure, rightly, high on the agenda in developed North. Viewed from a Swedish perspective many of the species on the national red list are rare owing to the fact that they occur at or close to their climatically controlled distribution limits or owing to changes in land use and methods in agriculture (most are associated with the agricultural landscape) and forestry and few of these species are at risk for extinction in a wider European or global perspective (Sjoberg 1994).