Open Peatland Research Articles

Biogeochemical Processes in the Soil-Groundwater System of a Forest-Peatland Complex, North Coast British Columbia, Canada

Abstract There is a limited understanding of the distribution and transport of solutes in the coastal forest-peatland systems of northern British Columbia, Canada. The purpose of this research was to evaluate the sources, concentration and flux of major ions and dissolved organic carbon (DOC) in the soil-groundwater system of a forest-peatland complex in the coastal western hemlock (CWH) forest zone. DOC dominated the groundwater flux, with most of it exported during high flow conditions. Inorganic ion concentration increased and DOC decreased with ground surface slope and community type from open peatland to bog woodland, bog forest, swamp forest and upland forest. Base cations, HC03 - and DOC in the peatland forest communities differed significantly (P < 0.05) from concentrations in the upland forest. The greatest concentrations of ions derived from mineral weathering were found in the upland forest where the absence of peat, deep mineral soil (85-465 cm) and steep surface slope (26%) combined to increa...

A new perspective on the δ13C signal preserved in speleothems using LC–IRMS analysis of bulk organic matter and compound specific stable isotope analysis

The analysis of δ13C in speleothem calcite is established as a palaeoenvironmental proxy, but records can often be complex to interpret due to multiple controls on the signal. Here we present a novel palaeoenvironmental application of non-purgeable organic carbon (NPOC) δ13C analysis and compound-specific isotope analysis (CSIA) to speleothems, and compare the resultant signals to a conventional calcite δ13C record. By accessing the carbon pool held in molecular organic matter, we are able for the first time to produce stable isotope records complementary to the CO2-derived signal from the speleothem calcite, and begin to identify separate ecological and climatic controls. In this sample from north-west Scotland, the calcite δ13C record and the NPOC δ13C both show fluctuations at a period of increasing wetness and change from birch woodland to more open peatland, the NPOC signal having a strong correlation with biomarkers for vegetation change. We interpret an inverse correlation between the NPOC and CO2 δ13C signals as primarily driven by changes in soil conditions impacting upon microbial activity, with decreased activity leading to a reduction in 13C enrichment of the residual organic matter (the NPOC fraction), and an increase in δ13C in the CO2 pool (calcite) due to a decrease in respired 12C. This opens the way for the application of parallel analyses to distinguish between soil conditions and vegetation parameters as the primary control on a record, and highlights the advantage of combining both inorganic and organic geochemical techniques in the palaeoenvironmental interpretation of stable carbon isotopic records.

Spore rain in relation to regional sources and beyond

While patterns of spore dispersal from single sources at short distances are fairly well known, information about ‘spore rain’ from numerous sources and at larger spatial scales is generally lacking. In this study, I sampled spore rain using a novel method consisting of 0.25–0.5 m2 cotton cloth traps at nine sites in the boreo‐nemoral vegetation zone in eastern Sweden during two seasons, using Sphagnum spores as a model. Traps were located in various landscapes (mainland, islands). Additional trapping was done in an arctic area (Svalbard) without spore production. Spore densities were tested against distance from the nearest source and area of sources (open peatlands) within different radii around each site (5, 10, 20, 50, 100, 200, 300, 400 km). The cloth method appeared reliable when accounting for precipitation losses, retaining approximately 20–60% of the spores under the recorded amounts of precipitation. Estimated spore densities ranged from 6 million m−2 and season within a large area source, via regional deposition of 50 000–240 000 spores m−2, down to 1000 m−2 at Svalbard. Spore rain for all sites was strongly related to distance from the nearest source, but when excluding samples taken within a source peatland, the amount of sources within 200 km was most important. Spores were larger at isolated island sites, indicating that a higher proportion originated from distant, humid areas. Immense amounts of Sphagnum spores are dispersed across regional distances annually in boreal areas, explaining the success of the genus to colonise nutrient poor wetlands. The detectable deposition at Svalbard indicates that about 1% of the regional spore rain has a trans‐ or intercontinental origin. The regional spore rain, originating from numerous sources in the landscape, is probably valid for most organisms with small diaspores and provides a useful insight in ecology, habitat restoration and conservation planning.

Forest Policy / Biosecurity

Abstract 7Massive fires in Indonesian peatlands in the 1990s and in eastern Russian peatlands in 2002 and last year have highlighted the need to manage forests overlying peat deposits, as well as converted peat forests and open peatlands. Peat or peaty soils, contain 65% or more of partially decayed vegetation, can burn freely or underground. They cover some 10 percent of worldwide forests and contain 25 percent of all terrestrial carbon. Recent massive greenhouse gas (GHG) emissions from fires in forested peat and peatland in Indonesia and in Russia highlight the need for policies to reduce GHG emissions. We discuss major peatland areas and quantify their carbon stocks and potential GHG emissions. Trends show that year-to-year emissions are variable, with huge pulses that are a significant share of global GHG emissions. We group suggested policy options into three approaches. The first approach, which will reduce peat-related product demand, includes a) restricting peat, and products produced on cleared forested peatland, from being labeled or counted in GHG reduction achievements, as renewable (which palm oil currently is considered); b) developing full substitutes for horticultural peat (comprising about half mined peat use); and c) developing renewable power in countries still dependent on peat for power generation. These options reduce the rate of developing newly mined peat/forest areas. Options for a second approach, which treat already drained and cleared forested peatlands, are: d) restoring functioning peat ecosystems by closing drainage ditches, allowing natural rewetting, and “seeding” with peat vegetation fragments, e) requiring current peat operators to restore mined areas right after all peat is removed, and f) converting them to other land uses, despite the acidic conditions of mined peat bogs. These options sharply reduce risks of peat fires. Finally, a third group of policy options reduces ignition risks and limit fire spread: g) developing monitoring, suppression techniques, h) organizing local landowner protection groups and i) improving public fire organizations.

Disentangling direct and indirect effects of water table drawdown on above‐ and belowground plant litter decomposition: consequences for accumulation of organic matter in boreal peatlands

AbstractPristine peatlands are carbon (C)‐accumulating wetland ecosystems sustained by a high water table (WT) and consequent anoxia that slows down decomposition. Persistent WT drawdown as a response to climate and/or land‐use change affects decomposition either directly through environmental factors such as increased oxygenation, or indirectly through changes in plant community composition. This study attempts to disentangle the direct and indirect effects of WT drawdown by measuring the relative importance of environmental parameters (WT depth, temperature, soil chemistry) and litter type and/or litter chemical quality on the 2‐year decomposition rates of above‐ and belowground litter (altogether 39 litter types). Consequences for organic matter accumulation were estimated based on the annual litter production. The study sites were chosen to form a three‐stage chronosequence from pristine (undrained) to short‐term (years) and long‐term (decades) WT drawdown conditions at three nutrient regimes. The direct effects of WT drawdown were overruled by the indirect effects through changes in litter type composition and production. Short‐term responses to WT drawdown were small. In long‐term, dramatically increased litter inputs resulted in large accumulation of organic matter in spite of increased decomposition rates. Furthermore, the quality of the accumulated matter greatly changed from that accumulated in pristine conditions. Our results show that the shift in vegetation composition as a response to climate and/or land‐use change is the main factor affecting peatland ecosystem C cycle, and thus dynamic vegetation is a necessity in any model applied for estimating responses of C fluxes to changing environment. We provide possible grouping of litter types into plant functional types that the models could utilize. Furthermore, our results clearly show a drop in soil summer temperature as a response to WT drawdown when an initially open peatland converts into a forest ecosystem, which has not yet been considered in the existing models.

Carbon dynamics in peatlands under changing hydrology: Effects of water level drawdown on litter quality, microbial enzyme activities and litter decomposition rates

Pristine peatlands are carbon (C) accumulating wetland ecosystems sustained by a high water level (WL) and consequent anoxia that slows down decomposition. Persistent WL drawdown as a response to climate and/or land-use change directly affects decomposition: increased oxygenation stimulates decomposition of the “old C” (peat) sequestered under prior anoxic conditions. Responses of the “new C” (plant litter) in terms of quality, production and decomposability, and the consequences for the whole C cycle of peatlands are not fully understood. WL drawdown induces changes in plant community resulting in shift in dominance from Sphagnum and graminoids to shrubs and trees. There is increasing evidence that the indirect effects of WL drawdown via the changes in plant communities will have more impact on the ecosystem C cycling than any direct effects. The aim of this study was to disentangle the direct and indirect effects of WL drawdown on the “new C” by measuring the relative importance of 1) environmental parameters (WL depth, temperature, soil chemistry) and 2) plant community composition on litter production, microbial activity, litter decomposition rates and, consequently, on the C accumulation. This information is crucial for modelling C cycle under changing climate and/or land-use. The effects of WL drawdown were tested in a large-scale experiment with manipulated WL at two time scales and three nutrient regimes. Furthermore, the effect of climate on litter decomposability was tested along a north-south gradient. Additionally, a novel method for estimating litter chemical quality and decomposability was explored by combining Near infrared spectroscopy with multivariate modelling. WL drawdown had direct effects on litter quality, microbial community composition and activity and litter decomposition rates. However, the direct effects of WL drawdown were overruled by the indirect effects via changes in litter type composition and production. Short-term (years) responses to WL drawdown were small. In long-term (decades), dramatically increased litter inputs resulted in large accumulation of organic matter in spite of increased decomposition rates. Further, the quality of the accumulated matter greatly changed from that accumulated in pristine conditions. The response of a peatland ecosystem to persistent WL drawdown was more pronounced at sites with more nutrients. The study demonstrates that the shift in vegetation composition as a response to climate and/or land-use change is the main factor affecting peatland ecosystem C cycle and thus dynamic vegetation is a necessity in any model applied for estimating responses of C fluxes to changes in the environment. The time scale for vegetation changes caused by hydrological changes needs to extend to decades. This study provides grouping of litter types (plant species and part) into functional types based on their chemical quality and/or decomposability that the models could utilize. Further, the results clearly show a drop in soil temperature as a response to WL drawdown when an initially open peatland converts into a forest ecosystem, which has not yet been considered in the existing models.

Forest floor carbon dioxide fluxes within an upland‐peatland complex in the Western Boreal Plain, Canada

AbstractThis study examined the midday (10:00 to 16:00) growing season (April to October) surface cover CO2 relationships with different canopy closures in a forested upland–peatland–pond complex in the Western Boreal Plain (WBP), north‐central Alberta, Canada. Large differences were observed among the forest floors of landscape units with different canopy covers with respect to midday total respiration [(Rtot) = vegetation respiration (Rveg) + soil respiration (Rsoil)] and gross ecosystem production (GEP), and the seasonal pattern of GEP and Rtot. Highest rates of Rtot followed the general progression of riparian &gt; upland &gt; open peatland &gt; covered peatland, with high Rsoil contributions. Strong correlations were observed between C:N, soil temperature, moisture and Rtot. Photosynthetic active radiation (PAR) controlled the GEP, which was highest in the open and covered peatland. GEP and Rtot were highest in the middle of the growing season when soil and air temperatures were warmest; in addition Rveg contributed more to Rtot during this time. However, Rsoil dominated the flux.This study demonstrated that controlling environmental factors on CO2 exchange cannot necessarily be extrapolated among land cover units within a sub‐humid region, such as Canada's WBP. In addition, forest floors of different land cover units, and microtopography should be taken into account when discussing understory contributions to CO2 exchange. Copyright © 2008 John Wiley &amp; Sons, Ltd.

Carbon pools and productivity in a 1-km 2 heterogeneous forest and peatland mosaic in Minnesota, USA

Determining the magnitude of carbon (C) storage in forests and peatlands is an important step towards predicting how regional carbon balance will respond to climate change. However, spatial heterogeneity of dominant forest and peatland cover types can inhibit accurate C storage estimates. We evaluated ecosystem C pools and productivity in the Marcell Experimental Forest (MEF), in northern Minnesota, USA, using a network of plots that were evenly spaced across a heterogeneous 1-km 2 mosaic composed of a mix of upland forests and peatlands. Using a nested plot design, we estimated the standing C stock of vegetation, coarse detrital wood and soil pools. We also estimated aboveground net primary production (ANPP) as well as coarse root production. Additionally we evaluated how vegetation cover types within the study area differed in C storage. The total ecosystem C pool did not vary significantly among upland areas dominated by aspen (160 ± 13 Mg C ha −1), mixed hardwoods (153 ± 19 Mg C ha −1), and conifers (197 ± 23 Mg C ha −1). Live vegetation accounted for approximately 50% of the total ecosystem C pool in these upland areas, and soil (including forest floor) accounted for another 35–40%, with remaining C stored as detrital wood. Compared to upland areas, total C stored in peatlands was much greater, 1286 ± 125 Mg C ha −1, with 90–99% of that C found in peat soils that ranged from 1 to 5 m in depth. Forested areas ranged from 2.6 to 2.9 Mg C ha −1 in ANPP, which was highest in conifer-dominated upland areas. In alder-dominated and black spruce-dominated peatland areas, ANPP averaged 2.8 Mg C ha −1, and in open peatlands, ANPP averaged 1.5 Mg C ha −1. In treed areas of forest and peatlands, our estimates of coarse root production ranged from 0.1 to 0.2 Mg C ha −1. Despite the lower production in open peatlands, all peatlands have acted as long-term C sinks over hundreds to thousands of years and store significantly more C per unit area than is stored in uplands. Despite occupying only 13% of our study area, peatlands store almost 50% of the C contained within it. Because C storage in peatlands depends largely on climatic drivers, the impact of climate changes on peatlands may have important ramifications for C budgets of the western Great Lakes region.

Requirement for particular seed‐borne fungi for seed germination and seedling growth of Xyris complanata, a pioneer monocot in topsoil‐lost tropical peatland in Central Kalimantan, Indonesia

AbstractHawaii yellow‐eyed grass (Xyris complanata: Xyridaceae) inhabits infertile, acidic peat soil in the rainy tropical zone in Southeast Asia. This monocot plant produces a large number of dormant seeds in order to make a large deposit to seed bank in the soil. Under laboratory conditions, surface‐sterilized X. complanata seeds are rarely able to germinate on sterilized peat moss bed; they require inoculation with either seed epiphytic or soil fungi to facilitate active seed germination. In the present study, three different genera of seed epiphytic fungi were isolated, and two common fungal genera, Fusarium sp. (strain R‐1) and Penicillium sp. (strain Y‐1), were found to promote seed germination of X. complanata. In sterile peat moss beds, the germination‐stimulating fungi also showed growth‐promoting effects on X. complanata seedlings. These results suggest that the seed germination‐promoting fungi likely function as genuine partners for X. complanata in tropical open peat lands.

Emergence and behaviors of acid-tolerant Janthinobacterium sp. that evolves N 2O from deforested tropical peatland

Using a soilless culture system mimicking tropical acidic peat soils, which contained 3 mg of gellan gum and 0.5 mg NO 3 −-N per gram of medium, a greenhouse gas, N 2O emitting capability of microorganisms in acidic peat soil in the area of Palangkaraya, Central Kalimantan, Indonesia, was investigated. The soil sampling sites included a native swamp forest (NF), a burnt forest covered by ferns and shrubs (BF), three arable lands (A-1, A-2 and A-3) and a reclaimed grassland (GL) next to the arable lands. An acid-tolerant Janthinobacterium sp. strain A1-13 (Oxalobacteriaceae, β-proteobacteria) isolated from A-1 soil was characterized as one of the most prominent N 2O-emitting bacteria in this region. Physiological characteristics of the N 2O emitter in the soilless culture system, including responses to soil environments, substrate concentration, C-source concentration, pH, and temperature, suggest that the N 2O emitting Janthinobacterium sp. strain A1-13 is highly adapted to reclaimed open peatland and primarily responsible for massive N 2O emissions from the acidic peat soils. Regulation of N 2O emitters in the reclaimed peatland for agricultural use is therefore one of the most important issues in preventing the greenhouse gas emission from acidic peat soil farmlands.

Hydrogeological influences on forest community type along forest–peatland complexes in coastal British Columbia

The prospect of harvesting forest–peatland systems in the coastal western hemlock forest region of British Columbia has created the need for an understanding of the interrelationship between topography, groundwater flow, and site productivity. Detailed topographic mapping including the use of ground-penetrating radar coupled with point measurements of specific yield, bulk density, saturated hydraulic conductivity, and groundwater level were used to determine the characteristics of groundwater flow along forest–peatland complexes. A topographic index was then used to characterize the spatial distribution of groundwater flow and site conditions (as represented by water table depth and organic horizon thickness) influencing forest community type. Forest community type mean index decreased from open peatland to upland forest. Areas with high slope indices had thicker organic horizons (0.7–1.8 m), water tables closer to the surface (0–0.2 m), and higher soil moisture contents (46–92%). These conditions affect successional dynamics and favour the invasion of hydrophytic species such as Sphagnum mosses. Areas with low slope index values were associated with shallower organic horizons (&lt;0.4 m), deeper water table (0.3 to &gt;1.6 m), and drier soil moisture (35–76%), favouring more prolific timber growth.

Hydrological processes controlling ground and surface water flow from a hypermaritime forest–peatland complex, Diana Lake Provincial Park, British Columbia, Canada

AbstractThe proposed harvesting of previously undeveloped forests in north coastal British Columbia requires an understanding of hydrological responses. Hydrometric and isotopic techniques were used to examine the hydrological linkages between meteoric inputs to the surface‐groundwater system and runoff response patterns of a forest‐peatland complex. Quickflow accounted for 72–91% of peak storm discharge. The runoff ratio was lowest for open peatland areas with thick organic horizons (0·02–0·05) due to low topographic gradients and many surface depressions capable of retaining surface water. Runoff ratio increased comparatively for ephemeral surface seep flows (0·06–0·40) and was greatest in steeply sloping forest communities with more permeable soils (0·33–0·69). The dominant mechanism for runoff generation was saturated shallow subsurface flow. Groundwater fluxes from the organic horizon of seeps (1·70–1·72 m3 day−1 m−1) were an important component of quickflow. The homogeneous δ2Hδ18O composition of groundwater indicated attenuation of the seasonal rainfall signal by mixing during recharge. The positive correlation (r2 = 0·64 and 0·38, α = 0·05) between slope index and δ18O values in groundwater suggests that the spatial pattern in the δ18O composition along the forest‐peatland complex is influenced by topography and provides evidence that topographic indices may be used to predict groundwater residence time. Copyright © 2006 John Wiley &amp; Sons, Ltd.

Nitrogen isotope signature variability in plant species from open peatland

We report natural abundance of 15N content in a suite of plants and lichens from a sloping open peatland in coastal northern British Columbia, Canada. A wide range of δ 15N values varying between −11 and +3‰ were observed in the studied species. Herbs, mosses, and shrubs generally grouped individually along the δ 15N gradient from enriched to more depleted values. This grouping probably reflects similar nitrogen acquiring strategies within the group, but some species with different strategies showed deviated δ 15N values from the cluster. Hummock-lawn gradient, which is illustrated as depth to water table, explains the variation in δ 15N signature of cryptogams: the deeper the groundwater table, the more depleted is the 15N. This trend might be explained by differences in nitrogen sources and/or differences in internal fractionation during nitrogen translocation processes.

Surface Peat Mass and Carbon Balance in a Hypermaritime Peatland

Net primary production (NPP) and decomposition were measured in a suite of representative microsite types, and 210Pb age was determined on near‐surface peat in a hypermaritime sloping peatland in British Columbia, Canada. Hummock and depression communities had significantly higher aboveground NPP, and were characterized by higher moss NPP than other communities. Mass loss of a standard litter material was significantly different among the microcommunities, possibly because of the differences in microsite oxic conditions and water movement. Incubated litter material lost C and gained N during the 2‐yr trial in all microcommunities, except for the Sphagnum austinii hummock, where N was lost at shallow depth. Low N content in the living Sphagnum and further N depletion in hummocks suggest that the hummock Sphagnum peat is recalcitrant to decomposition. Peat accumulation was found to be faster in hummock than in lawn communities. The hummock Sphagnum NPP and mass loss values were higher than published values for continental peatlands, possibly due to the wet and mild hypermaritime climate in this region. The recalcitrant nature of the litter and high NPP in hummocks likely account for rapid peat accumulation at the surface, whereas peat decomposition is most pronounced with depth, resulting in similar C sink strength as in hummocks in continental peatlands. Given that lawn community predominates, overall C sequestration capacity at the study site was estimated to be smaller than in continental peatlands. Possible range of C sink strength in sloping open peatlands in the hypermaritime region, therefore, is lower than or close to that in continental peatlands.

Environmental factors responsible for shaping an open peatland – forest complex on the hypermaritime north coast of British Columbia

The relationships between the distribution of plant communities and environmental factors were studied in an open peatland – forest complex of the hypermaritime north coast of British Columbia. The entire vegetation gradient, from open through forested peatlands to upland forest, was primarily explained by slope and minimum level of groundwater table. Environmental conditions in the upland Tsuga–Rhytidiadelphus forest were considerably different from those of the other communities; differences were small among the Sphagnum open peatland, the Pinus–Sphagnum woodland, the Chamaecyparis–Fauria forest, and the Thuja–Gaultheria forest. Highest level of groundwater table, conductivity minimum, pH, and dissolved oxygen merely helped distinguish the upland Tsuga–Rhytidiadelphus forest from all other communities. The wet Thuja–Gaultheria forest could be more vulnerable than the upland Tsuga–Rhytidiadelphus forest to local hydrological changes caused by harvesting. Consecutive intraannual measurements of environmental variables are important in clarifying the relationships between distribution of plant communities and environmental variables, especially for communities with peat accumulation.

Growth of Mosses in Relation to Climate Factors in a Hypermaritime Coastal Peatland in British Columbia, Canada

Intra-annual growth patterns of Racomitrium lanuginosum, Pleurozium schreberi, Sphagnum austinii, Sphagnum fuscum, Sphagnum rubellum, Sphagnum papillosum, Sphagnum lindbergii, Sphagnum tenellum, and Sphagnum pacificum were studied in relation to local precipitation and temperature in a sloping open peatland on the hypermaritime north coast of British Columbia. The growth of mosses was strongly correlated with precipitation and less with temperature. A temperature effect on growth was suggested by the emphasized correlation between growth and a combination of precipitation and temperature. Temperature thresholds for Sphagnum spp. were estimated to be lower than those for P. schreberi and R. lanuginosum. Growth rates of hummock Sphagnum spp. were lower and the seasonal growth pattern was less variable than those of hollow and lawn Sphagnum spp. Despite low vertical growth rates, hummock Sphagnum spp. had higher productivity than hollow and lawn Sphagnum spp. Winter-growth in this hypermaritime region appears to be important.

Recent expansion of jack pine in peatlands of southeastern Québec: A paleoecological study

Jack pine (Pinus banksiana) colonization and expansion in ombrotrophic peatlands of the Bas-Saint-Laurent region, southeastern Québec, was analyzed using macrofossil and dendrochronological analyses. During the last 80 years, and mainly between 1920 and 1945, several open peatlands dominated by Sphagnum species were invaded by jack pine following a fire event. This phenomenon appears to have no precedent over the last 8,900 years, at least in one of the study sites. Fires triggered the expansion by eliminating the Sphagnum mat and spreading thousands of pine seeds released by a few individuals. While fires contributed to the expansion of pines in bogs, this phenomenon may have been facilitated by a drier-than-average climatic period during the first part of the 20th century. The fact that dense jack pine stands are now growing on thick organic deposits indicates that this species has a wider ecological tolerance than previously known and/or that the Bas-Saint-Laurent peatlands have recently undergone major ecological and hydrological changes favouring the growth of non-bog species.

Regional Landscape Patterns and Distribution of the Siberian Flying Squirrel Pteromys volans in Northern Finland

Distribution of the Siberian flying squirrel Pteromys volans in northern Finland, at the edge of its global range, is fairly distinctive: the species is apparently absent in the western part of the region (Pohjanmaa), occurs regularly in the central part (Koillismaa), and only sporadically further east closer to the Russian border (northern Kainuu). In this study, we examined landscape structure in these three regions using geographic information system (GIS) and multi‐source land use and cover data to identify key characteristics in landscape structure that are linked to the observed distribution pattern of the Siberian flying squirrel in northern Finland. We analysed landscape structure by studying habitat type proportions in nature reserves and in large‐scale landscape samples within the regions. In addition, landscape configuration and connectivity were analysed within larger landscape sample plots. Our results suggest that the observed distribution pattern is associated with natural patterns in landscape structure at local and regional scales. Open peat lands, bogs and non‐forested habitats dominate the landscape in the western part of the region and possibly account for the absence of the Siberian flying squirrel. More subtle differences between the central and eastern parts of the region indicate regional scale landscape responses of the species. The relatively high amount of spruce‐dominated mixed forests in the central part was associated with the regular occurrence of the Siberian flying squirrel, whereas the increasing dominance of pine forests towards the east was associated with the low number of sightings. Forest management history is much alike in the different parts of the region, but the effects of forest management on the actual range of the species cannot be estimated owing to a lack of knowledge on accurate population trends in northern Finland. However, human‐caused fragmentation and large‐scale habitat degradation may have long‐term effects on the persistence of the species in northern Finland.

Biogenic fluxes of halomethanes from Irish peatland ecosystems

Irish peatland ecosystems have been shown to be important sources of low molecular weight halocarbons. Emission of CH 3Br, CH 3Cl, CH 3I and CHCl 3 was recorded from all peatland sites monitored, with minor flux of other halocarbons at certain sites. Fluxes were found to be highly linked to incident light, with strong diurnal cycles recorded at all open peatland sites. Estimates of halomethane emissions, particularly from coastal peatland and conifer plantation forest floor sites, suggests that these ecosystems may make a significant contribution to the global budgets of several important halocarbons. Global annual fluxes of 4.7 (0.1–151.9), 0.9 (0.1–3.3), 5.5 (0.9–43.4), and 1.4 (0.1–12.8) Gg yr −1 for CHCl 3, CH 3Br, CH 3Cl, and CH 3I, respectively, were determined for peatland ecosystems.

Afforestation of low-productivity peatlands in Sweden — the potential of natural seeding

In 1971, a series of five afforestation trials were established along a north-south gradient on open peatlands in Sweden. All areas were drained, fertilized and planted with Scots pine (Pinus sylvestris). Survival and height of the planted trees as well as the amount of natural establishment, i.e. downy birch (Betula pubescens), silver birch (Betula pendula), Norway spruce (Picea abies (L.) Karst.), Scots pine (Pinus sylvestris L.), and other deciduous species: (e.g. Salix sp., Sorbus aucuparia), by seeding from nearby forests were measured 18–22 years later. The amount of naturally established trees exceeded the number of living planted trees in all five areas. Next to downy birch, Scots pine was the most common naturally established species. Large variations in both amount and height of natural establishment were found along the climatic gradient. Planted trees were taller than naturally established trees, except for the northernmost area. Number and height of naturally established trees correlated positively to closeness to nearest forest and to nearest ditch. These trees also responded positively to PK fertilization in the three southernmost areas. In the two northernmost areas no such response was found. It was concluded that natural seeding from neighbouring forests can be counted on and recommended in afforestation of low-productive peatlands in Sweden, provided that downy birch is accepted as a dominant tree species.