| 1. |
- Mattsson, Eskil, 1981, et al.
(författare)
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Quantification of carbon stock and tree diversity of homegardens in a dry zone area of Moneragala District, Sri Lanka
- 2015
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Ingår i: Agroforestry Systems. - : Springer Science and Business Media LLC. - 1572-9680 .- 0167-4366. ; 89:3, s. 435-445
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Tidskriftsartikel (refereegranskat)abstract
- Homegarden agroforestry systems are suggested to hold a large potential for climate change mitigation and adaptation. This is due to their multifunctional role in providing income, food and ecosystem services while decreasing pressure on natural forests and hence saving and storing carbon. In this paper, above-ground biomass carbon and tree species diversity of trees was quantified in homegardens around two villages in the dry south-eastern part of Moneragala district of Sri Lanka. A total of 45 dry zone homegardens were sampled on size, diameter at breast height, tree height and species diversity. Using allometric equations, we find a mean above-ground biomass stock of 13 mega grams of carbon per hectare (Mg C ha−1) with a large range among homegardens (1–56 Mg C ha−1, n = 45) due to a variation of tree diversity and composition between individual homegardens. Mean above-ground carbon stock per unit area was higher in small homegardens (0.2 ha, 26 Mg C ha−1, n = 11) and statistically different compared to medium (0.4–0.8 ha, 9 Mg C ha−1, n = 27) and large (1.0–1.2 ha, 8 Mg C ha−1, n = 7) homegardens. In total, 4,278 trees were sampled and 70 tree species identified and recorded. The Shannon Wiener index were used to evaluate diversity per homegarden and ranged from 0.76 to 3.01 with a mean value of 2.05 ± 0.07 indicating a medium evenly distributed diversity of sampled tree species. The results show a vast heterogeneity in terms of carbon stock and tree diversity within the less studied dry zone homegardens; results that contribute to more knowledge of their expansion potential as well as climate mitigation and adaptation potential. The results are also useful for whether homegardens should be considered to be included as an activity to enhance natural forest cover within Sri Lanka’s newly commenced UN-REDD National Programme.
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| 2. |
- Montelius, Malin
(författare)
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Chlorine Cycling in Terrestrial Environments
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Chlorinated organic compounds (Clorg) are produced naturally in soil. Formation and degradation of Clorg affect the chlorine (Cl) cycling in terrestrial environments and chlorine can be retained or released from soil. Cl is known to have the same behaviour as radioactive chlorine-36 (36Cl), a long-lived radioisotope with a half-life of 300,000 years. 36Cl attracts interest because of its presence in radioactive waste, making 36Cl a potential risk for humans and animals due to possible biological uptake. This thesis studies the distribution and cycling of chloride (Cl–) and Clorg in terrestrial environments by using laboratory controlled soil incubation studies and a forest field study. The results show higher amounts of Cl– and Clorg and higher chlorination rates in coniferous forest soils than in pasture and agricultural soils. Tree species is the most important factor regulating Cl– and Clorg levels, whereas geographical location, atmospheric deposition, and soil type are less important. The root zone was the most active site of the chlorination process. Moreover, this thesis confirms that bulk Clorg dechlorination rates are similar to, or higher than, chlorination rates and that there are at least two major Clorg pools, one being dechlorinated quickly and one remarkably slower. While chlorination rates were negatively influenced by nitrogen additions, dechlorination rates, seem unaffected by nitrogen. The results implicate that Cl cycling is highly active in soils and Cl– and Clorg levels result from a dynamic equilibrium between chlorination and dechlorination. Influence of tree species and the rapid and slow cycling of some Cl pools, are critical to consider in studies of Cl in terrestrial environments. This information can be used to better understand Cl in risk-assessment modelling including inorganic and organic 36Cl.
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| 3. |
- Svensson, Teresia, 1975-, et al.
(författare)
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Chlorination of soil organic matter : The role of humus type and land use
- 2022
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Ingår i: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 806p2
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Tidskriftsartikel (refereegranskat)abstract
- The levels of natural organic chlorine (Clorg) typically exceed levels of chloride in most soils and is therefore clearly of high importance for continental chlorine cycling. The high spatial variability raises questions on soil organic matter (SOM) chlorination rates among topsoils with different types of organic matter. We measured Clorg formation rates along depth profiles in six French temperate soils with similar Cl deposition using 36Cl tracer experiments. Three forest sites with different humus types and soils from grassland and arable land were studied. The highest specific chlorination rates (fraction of chlorine pool transformed to Clorg per time unit) among the forest soils were found in the humus layers. Comparing the forest sites, specific chlorination was highest in mull-type humus, characterized by high microbial activity and fast degradation of the organic matter. Considering non-humus soil layers, grassland and forest soils had similar specific chlorination rates in the uppermost layer (0–10 cm below humus layer). Below this depth the specific chlorination rate decreased slightly in forests, and drastically in the grassland soil. The agricultural soil exhibited the lowest specific chlorination rates, similar along the depth profile. Across all sites, specific chlorination rates were correlated with soil moisture and in combination with the patterns on organic matter types, the results suggest an extensive Cl cycling where humus types and soil moisture provided best conditions for microbial activity. Clorg accumulation and theoretical residence times were not clearly linked to chlorination rates. This indicates intensive Cl cycling between organic and inorganic forms in forest humus layers, regulated by humic matter reactivity and soil moisture, while long-term Clorg accumulation seems more linked with overall deep soil organic carbon stabilization. Thus, humus types and factors affecting soil carbon storage, including vegetation land use, could be used as indicators of potential Clorg formation and accumulation in soils.
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| 4. |
- Svensson, Teresia, 1975-, et al.
(författare)
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Chlorine cycling and the fate of Cl in terrestrial environments
- 2021
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Ingår i: Environmental Science and Pollution Research. - : Springer. - 0944-1344 .- 1614-7499. ; 28:7, s. 7691-7709
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Tidskriftsartikel (refereegranskat)abstract
- Chlorine (Cl) in the terrestrial environment is of interest from multiple perspectives, including the use of chloride as a tracer forwater flow and contaminant transport, organochlorine pollutants, Cl cycling, radioactive waste (radioecology; 36Cl is of largeconcern) and plant science (Cl as essential element for living plants).During the past decades, there has been a rapid developmenttowards improved understanding of the terrestrial Cl cycle. There is a ubiquitous and extensive natural chlorination of organicmatter in terrestrial ecosystems where naturally formed chlorinated organic compounds (Clorg) in soil frequently exceed theabundance of chloride. Chloride dominates import and export from terrestrial ecosystems while soil Clorg and biomass Cl candominate the standing stock Cl. This has important implications for Cl transport, as chloride will enter the Cl pools resulting inprolonged residence times. Clearly, these pools must be considered separately in future monitoring programs addressing Clcycling. Moreover, there are indications that (1) large amounts of Cl can accumulate in biomass, in some cases representing themain Cl pool; (2) emissions of volatile organic chlorines could be a significant export pathway of Cl and (3) that there is aproduction of Clorg in tissues of, e.g. plants and animals and that Cl can accumulate as, e.g. chlorinated fatty acids in organisms.Yet, data focusing on ecosystem perspectives and combined spatiotemporal variability regarding various Cl pools are still scarce,and the processes and ecological roles of the extensive biological Cl cycling are still poorly understood.
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| 5. |
- Svensson, Teresia, 1975-
(författare)
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Measurements and fluxes of volatile chlorinated organic compounds (VOCl) from natural terrestrial sources : Measurement techniques and spatio-temporal variability of flux estimates
- 2019
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Volatile organic compounds (VOCs) and especially chlorinated VOCs (VOCls) are regarded as en viron mental risk substances in water bodies due to their toxic characteristics. Even in the atmosphere they highly impact atmospheric chemistry, e.g. degrading the ozone layer. Several studies have convincingly identified a number of natural VOCl sources thereby challenging the view of VOCls as only produced by humans. Yet, fundamental knowledge is still missing concerning the emission, distribution and the natural abundance of VOCls, especially regarding the high spatial and temporal variability of emissions from terrestrial sources. In the nuclear industry, Cl36 is a dosedominating radionuclide in some waste, and this adds to the need to better understand the processes, transport and fate of chlorine in the bio sphere. In this report 38 studies on VOCl flux measurement estimates were reviewed to summarize the current knowledge on spatiotemporal variations of different VOCls and various measurement tech niques.Chloromethane is the most studied VOCl compound and chloroform, the second most studied. A few other studies have estimated fluxes of additional VOCls such as tetrachloromethane (CCl4), methyl chloroform (CH3CCl3), tetrachloroethane (C2H2Cl4), freons (CFCs), chloroethane (C2H5Cl), bromodichloromethane (CHBrCl2). Studies were conducted in climates and terrestrial ecosystems ranging from arctic tundra to tropical rainforest but most studies focus on the temperate climate region. Wetlands and coastal systems dominate the studied ecosystems. Flux chambers are the most common method for investigation of the soilatmosphere exchange of VOCls, but a few studies used soil gas profiles and one the Relaxed Eddy Accumulation (REA) technique. Methodological uncertainties are mainly related to sample contamination, few replicates, chamber design, and chamber deployment (the time of measurement) effects on the soilatmosphere exchange itself. Despite the many challenges in measuring VOCls and estimating the fluxes, a substantial part of the chlorine in terrestrial ecosystems, and especially from wetlands and coastal areas, is emitted to the atmosphere as VOCls. In inland forested ecosystems, the release of Cl to the atmosphere could be as much as 0.1 g m–2, which is 40 % of the wet deposition and there are studies that suggest that freshwater wetlands are much larger source of chlorine in the atmosphere than previously understood.
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| 6. |
- Nilsson, Marie-Louise, et al.
(författare)
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Current-use and Organochlorine Pesticides and Polychlorinated Biphenyls in the Biodegradable Fraction of Source Separated Household Waste, Compost, and Anaerobic Digestate
- 2011
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Ingår i: Bulletin of Environmental Contamination and Toxicology. - : Springer Science and Business Media LLC. - 0007-4861 .- 1432-0800. ; 86, s. 60-64
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Tidskriftsartikel (refereegranskat)abstract
- Several current-use (a parts per thousand currency sign80 ng g(-1) dry weight) and organochlorine pesticides (a parts per thousand currency sign15 ng g(-1) dry weight) and polychlorinated biphenyls (a parts per thousand currency sign18 ng g(-1) dry weight) were found in the biodegradable fraction of source separated household waste, compost, and/or anaerobic digestate. The degradation rates of individual compounds differ depending on the treatment. Dieldrin and pentachloroaniline, e.g., degrade more rapidly than the waste is mineralized and accumulates in the products after all treatments. Many organochlorines degrade at the same rate as the waste and have the same concentrations in the waste and products. Chlorpyrifos degrades slower than the waste and accumulates in all products and ethion during anaerobic digestion. The polychlorinated biphenyls and some pesticides show different degradations rates relative the waste during different processes. Understanding the degradation of the contaminants under different conditions is necessary to develop quality criteria for the use of compost and digestate.
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| 7. |
- Collier, Elizabeth S., et al.
(författare)
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Still just a matter of taste? Sensorial appreciation of seafood is associated with more frequent and diverse consumption
- 2024
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Ingår i: APPETITE. - : ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD. - 0195-6663 .- 1095-8304. ; 198
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Tidskriftsartikel (refereegranskat)abstract
- Improving health and sustainability outcomes in WEIRD (Western, Educated, Industrial, Rich, Democratic) nations necessitates a reduction in red meat consumption. Seafood is often overlooked in achieving this goal. However, simply consuming more of familiar fish species places high stress on production of these species. For this reason, diversification of seafood consumption is also critical. Here the motives for seafood consumption (frequency and diversity) are investigated across two studies by adapting the 4Ns survey to the seafood category. This 16-item survey measures four factors underpinning meat consumption: namely that it is 'Natural', 'Necessary', 'Normal' and 'Nice'. Swedish consumers' hedonic and sensory expectations of two herring concepts (traditional pickled contra novel minced and presented as a burger) are also evaluated in relation to the 4Ns. Study 1 (N = 304) revealed that the seafood 4Ns scale had a similar underlying structure to that of meat and had good test-retest reliability. Study 2 (N = 514) showed that consumers expected to like the pickled herring (associated with being 'seasoned', 'salty', 'sweet', 'firm', 'juicy', 'chewy', and 'slimy') more than the minced herring (associated with being 'mushy', 'fishy', 'grainy', 'dry' and having 'small bones'), and that 'Nice' scores affected expectations of both herring concepts. Food neophobia correlated inversely with seafood consumption frequency, expected liking, the 'Nice' subscale, and food agency. Critically, in both studies, enjoyment of seafood (higher 'Nice' scores) predicted more frequent and diverse seafood consumption, whilst agreeing that seafood is 'Necessary' for health predicted only consumption frequency, not diversity. Communicating the positive sensory attributes of seafood and developing novel product concepts in ways that disconfirm sceptical consumers' negative sensory expectations may increase acceptance of both familiar and unfamiliar seafood concepts.
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| 8. |
- Johansson, Victor, et al.
(författare)
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Fewer butterflies and a different composition of bees, wasps and hoverflies on recently burned compared to unburned clear-cuts, regardless of burn severity
- 2020
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Ingår i: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 463
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Tidskriftsartikel (refereegranskat)abstract
- Insect pollinators are declining, which often is related to intensified agriculture. Less focus has been on the effect of forestry. In many boreal forests, clear-cutting has replaced fire as the main disturbance agent, which has been negative for many species. Therefore, prescribed burning is performed, often on clear-cuts. Knowledge on the effect of fire on pollinators is, however, scarce. We sampled pollinators and their resources in 22 burned and 15 unburned clear-cuts in and around a large wildfire area in Sweden, three years after fire. We compared potential pollinator resources as well as richness, abundance and community composition of four groups of pollinators: bees (totaling 583 individuals), wasps (1226), hoverflies (416), and butterflies (7 2 8) between burned and unburned clear-cuts. Moreover, we analyzed the effect of burn severity (depth of remaining humus). We show that the diversity and cover of potential nectar/pollen plants were clearly lower in burned clear-cuts, while potential nesting resources were higher. Butterfly richness was 67% lower and abundance 89% lower in burned clear-cuts. Differences in richness and abundance were smaller for bees, wasps, and hoverflies, but their species composition differed. We found no effect of burn severity on pollinators or their resources. We conclude that burned clear-cuts have fewer pollinators three years after fire, which is driven by a loss of butterflies. However, changes in species composition from clear-cut fires could complement the fauna of unburned sites when mixed at landscape level. Future studies should follow vegetation and pollinator communities over longer time periods following clear-cut burning.
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| 9. |
- Mattsson, Eskil, 1981, et al.
(författare)
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Heterogeneity and assessment uncertainties in forest characteristics and biomass carbon stocks: Important considerations for climate mitigation policies
- 2016
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Ingår i: Land Use Policy. - : Elsevier BV. - 0264-8377 .- 1873-5754. ; 59, s. 84-94
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Tidskriftsartikel (refereegranskat)abstract
- The management of forests to store carbon and mitigate climate change has received significant inter- national attention during the last decade. Using in situ data from a 2008–2009 forest inventory field campaign in Sri Lanka, this study describes the structural characteristics and carbon stocks of six natural forest types. This paper has a dual scope: i) to highlight the variation in carbon stored in aboveground biomass within and between forest types and ii) to determine the implications of the allometric equa- tions chosen to calculate biomass carbon stocks. This study concerns work related to climate change interventions, such as Reducing Emissions from Deforestation and Forest Degradation (REDD+) and other forest-related, performance-based initiatives that require proper monitoring, reporting, and verification of carbon stocks, sinks and emissions. The results revealed that forests are heterogeneous in terms of tree density and height–diameter relationships, both between and within the six forest types investigated. The mean aboveground carbon stock in the different forest types ranged from 22 to 181 Mg C ha−1 , and there were statistically significant differences in the carbon stocks of the six forest types in 7 of 15 cases. The estimated carbon stock depended heavily on the allometric equation used for the calculations, the variables, and its application to the specific life zone. Due to the diversity of forest structures, these results suggest that caution should be taken when applying default values to estimate forest carbon stocks and emission values in reporting and accounting schemes. The results also indicated the need for allometric equations that are context-specific for different forest types. Therefore, new field investigations and mea- surements are needed to determine these specific allometric equations, as well as the potential variation in forest carbon stocks in tropical natural forests.
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| 10. |
- Ranlund, Åsa, et al.
(författare)
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Epiphytic lichen responses to environmental change due to clear-cutting differ among tree taxa
- 2018
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Ingår i: Journal of Vegetation Science. - : Wiley. - 1100-9233 .- 1654-1103. ; 29:6, s. 1065-1074
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Tidskriftsartikel (refereegranskat)abstract
- Question Many species-rich communities are associated with a foundation species. While we often have detailed information about the foundation species, we know less about its associated species. We explore such a situation, comparing the responses of lichen species associated with different tree taxa, which differ in successional strategy, to the environmental change that takes place when the surrounding trees are clear-cut. Location Boreal forests in Sweden. Methods We illustrated general differences in lichen species composition among four tree taxa and three stand categories using ordination of species occurrences. To analyse responses to clear-cutting we modelled the occurrence probability individually for 144 epiphytic lichen species from the lower 2 m of 2,400 tree trunks of four tree taxa in 130 stands, and compared trees in closed-canopy forests with those retained in logged stands, using Bayesian hierarchical models. Results The composition of lichens on aspen trees deviated clearly from that on the other tree species. Also lichen responses to logging differed among main host tree taxa, where lichen species associated with birches, European aspen, and Scots pine increased in probability of occurrence on trees in logged areas compared to intact forest, while lichen species associated with Norway spruce decreased. We found that time lags for changes in occupancy existed primarily in the increase, but not in the decline, of the groups of lichens associated with different tree taxa. Conclusions Lichens associated with different tree taxa vary in their response to the environmental change brought about by logging, but in a way that differs from the differences in species composition among host trees. Our results highlight the importance of considering the taxa of trees in forest management for the conservation of their associated lichen species. The extent to which the ecology of foundation species influences their associated species merits further inquiry, since such knowledge may facilitate predictions of responses of associated species also in other species-rich communities.
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