| 1. |
- Alarcon Ferrari, Cristian, et al.
(författare)
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Citizen Science as Democratic Innovation That Renews Environmental Monitoring and Assessment for the Sustainable Development Goals in Rural Areas
- 2021
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Ingår i: Sustainability. - : MDPI. - 2071-1050. ; 13:5
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Tidskriftsartikel (refereegranskat)abstract
- This commentary focuses on analyzing the potential of citizen science to address legitimacy issues in the knowledge base used to guide transformative governance in the context of the United Nation’s Sustainable Development Goals (henceforth SDGs). The commentary develops two interrelated arguments for better understanding the limits of what we term “traditional” Environmental Monitoring and Assessment (EMA) as well as the potential of citizen science (CS) for strengthening the legitimacy of EMA in the local implementation of SDGs. We start by arguing that there is an urgent need for a profound renewal of traditional EMA to better implement the SDGs. Then, we present CS as a democratic innovation that provides a path to EMA renewal that incorporates, develops, and extends the role of CS in data production and use by EMA. The commentary substantiates such arguments based on current approaches to CS and traditional EMA. From this starting point, we theorize the potential of CS as a democratic innovation that can repurpose EMA as a tool for the implementation of the SDGs. With a focus on the implementation of SDG15 (Life on Land) in local contexts, the commentary presents CS as a democratic innovation for legitimate transformative governance that can affect socio-ecological transitions. We see this approach as especially appropriate to analyze the implementation of SDGs in rural settings where a specific resource nexus can create conflict-laden contexts with much potential for a renewed EMA to support transformative governance towards Agenda 2030.
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| 2. |
- Almér, Stefan, et al.
(författare)
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Global stability analysis of DC-DC converters using sampled-data modeling
- 2004
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Ingår i: PROCEEDINGS OF THE 2004 AMERICAN CONTROL CONFERENCE, VOLS 1-6. - 0780383354 ; , s. 4549-4554
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Konferensbidrag (refereegranskat)abstract
- The paper presents stability analysis of a class of pulse-width modulated (PWM) systems which incorporates many different DC-DC converters. Two types of pulse-width modulation (digital and analog control) are considered. A procedure is developed for systematic search for Lyapunov functions. The state space is partitioned in such a way that stability is verified if a set of coupled Linear Matrix Inequalities (LMIs) is feasible. Global stability is considered as well as the computation of local regions of attraction.
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| 3. |
- Almér, Stefan, et al.
(författare)
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Stability analysis of a class of PWM systems
- 2007
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Ingår i: IEEE Transactions on Automatic Control. - 0018-9286 .- 1558-2523. ; 52:6, s. 1072-1078
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Tidskriftsartikel (refereegranskat)abstract
- This note considers stability analysis of a class of pulsewidth modulated (PWM) systems that incorporates several different switched mode dc-de- converters. The systems of the class typically have periodic solutions. A sampled data model is developed and used to prove stability of these solutions. Conditions for global and local exponential stability are derived using quadratic and piecewise quadratic Lyapunov functions. The state space is partitioned and the stability conditions are verified by checking a set of coupled linear matrix inequalities (LMIs).
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| 4. |
- Aronsson, Per, et al.
(författare)
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An operational decision support tool for stump harvest
- 2011
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A multi-criteria decision support tool was developed to optimise stump harvesting for energy in Sweden. The decision tool takes account of multiple, sometimes conflicting, criteria relating to stump harvest; energy and climate, economics, biodiversity, and soil and water. Data on harvested stems are used as primary input data in the tool. Such data are routinely collected in harvester computers. The tool effectively deals with mixed sets of data; quantitative harvest data are re-calculated to metric (e.g. stump biomass), and qualitative data (e.g. biodiversity implications) are incorporated. A digital terrain map derived from air-borne laser scanning provides basic data for estimating soil wetness, while digital maps of water courses, key habitats and protected areas, or other sensitive habitats, are used to identify potentially and practically harvestable stumps.In four sub-models, an index from 0 to 10 is calculated for each stump, with 0 representing ‘Not at all suitable’ and 10 ‘Highly suitable for extraction’. Through this, a stump of high value for wood-living species is assigned a low index in the biodiversity sub-model and a large, easily accessible stump is assigned a high index in the economic sub-model. When calculating the net index, the sub-indices can be weighted according to the preferences of the end-user.An energy and climate sub-model incorporates greenhouse gas (GHG) emissions from forest operations and the effect of advancing GHG emissions when stump biomass is incinerated instead of being left to decompose. In the economic sub-model the potential monetary return from each stump is calculated based on estimated revenue from harvested stump biomass and the costs of stump harvesting and forwarding operations (based on cost functions and GIS calculations of transport distances).The biodiversity sub-model considers four types of wood-dependent organisms (lichens, mosses, insects and fungi) in terms of their habitat requirements, vulnerability, sun exposure preferences, locality, etc. A panel of external experts has drawn up a grading scale of stump values for the different taxonomic groups. The proximity to key habitats and exposure to sunlight are derived from a spatial model.Soil and water issues are handled within a sub-model estimating the consequences for long-term soil fertility (nutrient cycling and soil compaction) and water (leaching of plant nutrients and mercury, and particle transport due to soil damage by heavy machinery).The tool offers the end-user possibilities to prioritise and plan for cost-effective stump harvesting, while minimising negative environmental impacts.
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| 5. |
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| 6. |
- Bina, Pavel, et al.
(författare)
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Awareness, views and experiences of Citizen Science among Swedish researchers — two surveys
- 2021
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Ingår i: JCOM - Journal of Science Communication. - : Sissa Medialab Srl. - 1824-2049. ; 20:06
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Tidskriftsartikel (refereegranskat)abstract
- In 2021 Sweden’s first national portal for citizen science will be launched to help researchers practice sustainable and responsible citizen science with different societal stakeholders. This paper present findings from two surveys on attitudes and experiences of citizen science among researchers at Swedish universities. Both surveys provided input to the development of the national portal, for which researchers are a key stakeholder group. The first survey (n=636) was exclusively focused on citizen science and involved researchers and other personnel at Swedish University of Agricultural Science (SLU). 63% of respondents at SLU had heard about citizen science (CS) prior to the survey; however a majority of these (61%) had not been involved in any CS initiative themselves. Dominant reasons for researchers choosing a CS approach in projects were to enable collection of large amounts of data (68%), improving the knowledge base (59%), improving data quality (25%), promote participants’ understanding in research (21%) and promote collaboration between the university and society (20%). The other survey (n=3 699) was on the broader topic of communication and open science, including questions on CS, and was distributed to researchers from all Swedish universities. 61% of respondents had not been engaged in any research projects where volunteers were involved in the process. A minority of the researchers had participated in projects were volunteers had collected data (18%), been involved in internal or external communication (16%), contributed project ideas (14%) and/or formulated research questions (11%). Nearly four out of ten respondents (37%) had heard about CS prior to the survey. The researchers were more positive towards having parts of the research process open to citizen observation, rather than open to citizen influence/participation. Our results show that CS is a far from well-known concept among Swedish researchers. And while those who have heard about CS are generally positive towards it, researchers overall are hesitant to invite citizens to take part in the research process.
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| 7. |
- Bradter, Ute, et al.
(författare)
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Can opportunistically collected Citizen Science data fill a data gap for habitat suitability models of less common species?
- 2018
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Ingår i: Methods in Ecology and Evolution. - 2041-210X. ; 9, s. 1667-1678
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Tidskriftsartikel (refereegranskat)abstract
- 1. Opportunistically collected species observations contributed by volunteer reporters are increasingly available for species and regions for which systematically collected data are not available. However, it is unclear if they are suitable to produce reliable habitat suitability models (HSMs), and hence if the species-habitat relationships found and habitat suitability maps produced can be used with confidence to advice conservation management and address basic and applied research questions.2. We evaluated HSMs with opportunistically collected observations against HSMs with systematically collected observations. We enhanced the opportunistically collected presence-only data by adding inferred species absences. To obtain inferred absences, we asked individual reporters about their identification skills and if they reported certain species consistently and combined this information with their observations. We evaluated several HSM methods using a forest bird species, Siberian jay (Perisoreus infaustus), in Sweden: logistic regression with inferred absences, two versions of MaxEnt, a model combining presence-absence with presence-only observations and a Bayesian site-occupancy-detection model.3. All HSM methods produced nationwide habitat suitability maps of Siberian jay that agreed well with systematically collected observations (AUC: 086-0.88) and were very similar to a habitat suitability map produced from the HSM with systematically collected observations (Spearman rho: 0.94-0.98). At finer geographical scales there were differences among methods.4. At finer scale, the resulting habitat suitability maps from logistic regression with inferred absences agreed better with results from systematically collected observations than other methods. The species-habitat relationships found with logistic regression also agreed well with those found from systematically collected data and with prior expectations based on the species ecology.5. Synthesis and application. For many regions and species, systematically collected data are not available. By using inferred absences from high-quality, opportunistically collected contributions of few very active reporters in logistic regression we obtained HSMs that produced results similar to those from a systematic survey. Adding high-quality inferred absences to opportunistically collected data is likely possible for many less common species across various organism groups. Well-performing HSMs are important to facilitate applications such as spatial conservation planning and prioritization, monitoring of invasive species, understanding species habitat requirements or climate change studies.
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| 8. |
- Bäcklund, Sofia, et al.
(författare)
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A Pine Is a Pine and a Spruce Is a Spruce – The Effect of Tree Species and Stand Age on Epiphytic Lichen Communities
- 2016
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- With an increasing demand for forest-based products, there is a growing interest in introducing fast-growing non-native tree species in forest management. Such introductions often have unknown consequences for native forest biodiversity. In this study, we examine epiphytic lichen species richness and species composition on the trunks of non-native Pinus contorta and compare these to the native Pinus sylvestris and Picea abies in managed boreal forests in northern Sweden across a chronosequence of age classes. Overall, we recorded a total of 66,209 lichen occurrences belonging to 57 species in the 96 studied forest stands. We found no difference in species richness of lichens between stands of P. contorta and P. sylvestris, but stands of P. abies had higher total species richness. However, species richness of lichens in stands of P. abies decreased with increasing stand age, while no such age effect was detected for P. contorta and P. sylvestris. Lichen species composition progressively diverged with increasing stand age, and in 30-year-old stands all three tree species showed species-specific assemblages. Epiphytic lichen assemblages in stands of 30-year-old P. contorta were influenced by greater basal area, canopy closure, and average diameter at breast height, P. abies stands by higher branch density and canopy closure, and stands of P. sylvestris by greater bark crevice depth. Differences in lichen species richness and composition were mainly explained by canopy closure and habitat availability, and the greater canopy closure in mature P. abies stands promoted the colonization and growth of calicioid lichen species. Our results indicate that the non-native P. contorta have similar species richness as the native P. sylvestris. The main difference in lichen species richness and composition is between P. abies and Pinus spp. in managed forests of boreal Sweden.
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| 9. |
- Bäcklund, Sofia, et al.
(författare)
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Composition of functional groups of ground vegetation differ between planted stands of non-native Pinus contorta and native Pinus sylvestris and Picea abies in northern Sweden
- 2015
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Ingår i: Silva Fennica. - : Finnish Society of Forest Science. - 0037-5330 .- 2242-4075. ; 49
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Tidskriftsartikel (refereegranskat)abstract
- Intensified forestry increases the interest in replacing native tree species with fast growing nonnative species. However, consequences for native biodiversity and ecosystem functioning are poorly understood. We compared cover and composition of major functional groups of ground vegetation between planted stands of non-native Pinus contorta Dougl. var. latifolia Engelm. and native conifers Pinus sylvestris L. and Picea abies (L.) H. Karst. in northern boreal Sweden. We quantified the ground cover of lichens, bryophytes, vascular plants and ground without vegetation (bare ground) in 96 stands covering three different age classes (15, 30 and 85 years old). Our study revealed differences in ground vegetation patterns between non-native and native managed forests, and that these differences are linked to stand age and differences in canopy cover. Total vascular plant cover increased with increasing stand age for all tree species, with P. contorta stands having higher cover than both native conifers. The ground cover of lichens was, although generally low, highest in stands of Pinus sylvestris. P. abies stands had a lower cover of vascular plants, but bare ground was more common compared with P. contorta. Our results suggest that the use of P. contorta as an alternative tree species in Fennoscandian forestry will influence native ground vegetation patterns. This influence is likely to change with time and future research should consider both temporal and landscape-scale effects from shifting tree-species dominance to Pinus contorta and other non-native tree species.
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| 10. |
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| 11. |
- Bäcklund, Sofia, et al.
(författare)
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Tree and stand structure of the non-native Pinus contorta in relation to native Pinus sylvestris and Picea abies in young managed forests in boreal Sweden
- 2018
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Ingår i: Scandinavian Journal of Forest Research. - : Informa UK Limited. - 0282-7581 .- 1651-1891. ; 33, s. 245-254
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Tidskriftsartikel (refereegranskat)abstract
- Managed forest stands are typically younger and structurally less diverse than natural forests. Introduction of non-native tree species might increase the structural changes to managed forest stands, but detailed analyses of tree-and stand-structures of native and non-native managed forests are often lacking. Improved knowledge of non-native forest structure could help clarify their multiple values (e.g. habitat for native biodiversity, bioenergy opportunities). We studied the structural differences between the introduced, non-native Pinus contorta and the native Pinus sylvestris and Picea abies over young forest stand ages (13-34 years old) in managed forests in northern Sweden. We found that P. contorta stands had greater mean basal areas, tree heights, diameters at breast height, and surface area of living branches than the two native species in young stands. The surface area of dead attached branches was also greater in P. contorta than P. abies. Although this indicates greater habitat availability for branch-living organisms, it also contributes to the overall more shaded conditions in stands of P. contorta. Only one older 87 years old P. contorta stand was available, and future studies will tell how structural differences between P. contorta and native tree species develop over the full forestry cycle.
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| 12. |
- Dawson, Samantha, et al.
(författare)
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Handbook for the measurement of macrofungal functional traits: A start with basidiomycete wood fungi
- 2019
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Ingår i: Functional Ecology. - : Wiley. - 0269-8463 .- 1365-2435. ; 33, s. 372-387
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Forskningsöversikt (refereegranskat)abstract
- Functional traits are widely recognized as a useful framework for testing mechanisms underlying species community assemblage patterns and ecosystem processes. Functional trait studies in the plant and animal literature have burgeoned in the past 20 years, highlighting a need for standardized ways to measure ecologically meaningful traits across taxa and ecosystems. However, standardized measurements of functional traits are lacking for many organisms and ecosystems, including fungi. Basidiomycete wood fungi occur in all forest ecosystems world-wide, where they are decomposers and also provide food or habitat for other species, or act as tree pathogens. Despite their major role in the functioning of forest ecosystems, the understanding and application of functional traits in studies of communities of wood fungi lags behind other disciplines. As the research field of fungal functional ecology is growing, there is a need for standardized ways to measure fungal traits within and across taxa and spatial scales. This handbook reviews pre-existing fungal trait measurements, proposes new core fungal traits, discusses trait ecology in fungi and highlights areas for future work on basidiomycete wood fungi. We propose standard and potential future methodologies for collecting traits to be used across studies, ensuring replicability and fostering between-study comparison. Combining concepts from fungal ecology and functional trait ecology, methodologies covered here can be related to fungal performance within a community and environmental setting. This manuscript is titled "a start with" as we only cover a subset of the fungal community here, with the aim of encouraging and facilitating the writing of handbooks for other members of the macrofungal community, for example, mycorrhizal fungi. A is available for this article.
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| 13. |
- Dawson, Samantha, et al.
(författare)
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Just how big is intraspecific trait variation in basidiomycete wood fungal fruit bodies?
- 2020
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Ingår i: Fungal Ecology. - : Elsevier BV. - 1754-5048 .- 1878-0083. ; 46
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Tidskriftsartikel (refereegranskat)abstract
- As the use of functional trait approaches is growing in fungal ecology, there is a corresponding need to understand trait variation. Much of trait theory and statistical techniques are built on the assumption that interspecific variation is larger than intraspecific variation. This allows the use of mean trait values for species, which the vast majority of trait studies adopt. We examined the size of intra- vs. inter-specific variation in two wood fungal fruit body traits: size and density. Both coefficients of variation (CV) and Trait Probability Density analyses were used to quantify trait variation. We found that intraspecific variation in fruit body density was more than twice as variable as interspecific variation, and fruit body size was hugely variable (CVs averaged 190%), although interspecific variation was larger. Further, there was a very high degree of overlap in the trait space of species, indicating that there may be little niche partitioning at the species level. These findings show that intraspecific variation is highly important and should be accounted for when using trait approaches to understand fungal ecology. More data on variation of other fungal traits is also desperately needed to ascertain whether the high level of variation found here is typical for fungi. While the need to measure individuals does reduce the ability to generalise at the species level, it does not negate the usefulness of fungal trait measurements. There are two reasons for this: first, the ecology of most fungal species remains poorly known and trait measurements address this gap; and secondly, if trait overlap between species more generally is as much as we found here, then individual measurements may be more helpful than species identity for untangling fungal community dynamics. (C) 2019 The Authors. Published by Elsevier Ltd.
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| 14. |
- Dawson, Samantha K., et al.
(författare)
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Convergence of fungal traits over time in natural and forestry-fragmented patches
- 2020
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Ingår i: Biological Conservation. - : Elsevier BV. - 0006-3207 .- 1873-2917. ; 251
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Tidskriftsartikel (refereegranskat)abstract
- Setting aside small remnant patches of high biodiversity forest within managed forest landscapes is often used as conservation measure to provide a refuge and future source population of forest biodiversity, including wood-inhabiting fungal communities. Yet little is known about the long-term fungal community assembly, how these small, isolated patches change through time and how forest management in the surrounding landscape impacts traits and community functionality housed within. We applied a joint species distribution model to compare how fungal traits and communities changed over two survey periods undertaken ~20 years apart in boreal forest set-aside and natural patches. Natural patches in naturally fragmented landscapes were considered reference forests for small, remnant, near-natural forest patches in intensively managed forest landscapes. We found the majority of fungal traits converged over time between set-aside and natural patches, without changes in overall species richness. Red-listed species occurrence was initially lower in set-aside patches, but reached a comparable level of natural patches over time as a result of opposing changes in both patch types. Functional trait changes were larger in set-aside patches, but convergence was also related to opposing changes in natural patches. This is the first study to directly measure and test wood fungal community trait-environment relationships over time in small, high-conservation value forest patches. The long-term functional trait and red-listed species values of set-asides, coupled with their capacity for old-growth recovery, make them valuable focal areas for conservation.
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| 15. |
- Dawson, Samantha, et al.
(författare)
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The traits of "trait ecologists": An analysis of the use of trait and functional trait terminology
- 2021
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Ingår i: Ecology and Evolution. - : Wiley. - 2045-7758. ; 11, s. 16434-16445
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Tidskriftsartikel (refereegranskat)abstract
- Trait and functional trait approaches have revolutionized ecology improving our understanding of community assembly, species coexistence, and biodiversity loss. Focusing on traits promotes comparability across spatial and organizational scales, but terms must be used consistently. While several papers have offered definitions, it remains unclear how ecologists operationalize "trait" and "functional trait" terms. Here, we evaluate how researchers and the published literatures use these terms and explore differences among subdisciplines and study systems (taxa and biome). By conducting both a survey and a literature review, we test the hypothesis that ecologists' working definition of "trait" is adapted or altered when confronting the realities of collecting, analyzing and presenting data. From 486 survey responses and 712 reviewed papers, we identified inconsistencies in the understanding and use of terminology among researchers, but also limited inclusion of definitions within the published literature. Discrepancies were not explained by subdiscipline, system of study, or respondent characteristics, suggesting there could be an inconsistent understanding even among those working in related topics. Consistencies among survey responses included the use of morphological, phonological, and physiological traits. Previous studies have called for unification of terminology; yet, our study shows that proposed definitions are not consistently used or accepted. Sources of disagreement include trait heritability, defining and interpreting function, and dealing with organisms in which individuals are not clearly recognizable. We discuss and offer guidelines for overcoming these disagreements. The diversity of life on Earth means traits can represent different features that can be measured and reported in different ways, and thus, narrow definitions that work for one system will fail in others. We recommend ecologists embrace the breadth of biodiversity using a simplified definition of "trait" more consistent with its common use. Trait-based approaches will be most powerful if we accept that traits are at least as diverse as trait ecologists.
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| 16. |
- Edman, Mattias, et al.
(författare)
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Fungi and wind strongly influence the temporal availability of logs in an old-growth spruce forest
- 2007
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Ingår i: Ecological Applications. - : Wiley. - 1051-0761 .- 1939-5582. ; 17:2, s. 482-490
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Tidskriftsartikel (refereegranskat)abstract
- Coarse woody debris (CWD) is a key habitat for many species in forest ecosystems. To ensure the long-term survival of such species, forest management regimes must include measures that promote dead wood dynamics similar to those of natural forests. Thus, information on CWD dynamics under natural conditions is required, including data pertaining to the underlying agents of disturbance. This study examines modes of mortality, decay rates, and temporal patterns in the availability of Picea abies logs in a Swedish old-growth forest affected by internal, small-scale disturbance. All 684 logs in a 6.6-ha plot were mapped and classified into one of six decay classes. Logs in the early stages of decay were examined for the presence of heart-rot fungi. Six years later all logs were re-inventoried, including newly formed logs. Matrix models based on the transition rates between decay classes showed that it took about 60 years for 90% of the logs to decay beyond class 6 (a deformed trunk with soft wood). Large logs (≥26 cm) decayed 40% more slowly than small logs (≤25 cm). The initial volume of logs was 37.6 m3/ha but increased to 44.8 m 3/ha after six years. In addition, there was a large shift in the decay-class distribution. The volume of logs in early and late decay classes increased by 71% and 45%, respectively, while the volume of logs in the intermediate decay classes decreased by 32%. The fluctuations appear to result from pulses in mortality, driven by a combination of strong winds and the heart-rot fungus, Phellinus chrysoloma, which was present in more than 30% of all logs at an early stage of decay. These results show that large temporal fluctuations in dead wood also occur in the absence of large-scale disturbance, and that heart-rot fungi are important factors driving the overall dynamics of dead wood. Since many wood-inhabiting species are naturally rare and have very specific substrate demands, such temporal variability in dead wood availability may have effects on biodiversity and should be taken into account when designing small, protected forest areas.
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| 17. |
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| 18. |
- Fraver, Shawn, et al.
(författare)
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Demographics and disturbance history of a boreal old-growth Picea abies forest
- 2008
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Ingår i: Journal of Vegetation Science. - : Wiley. - 1100-9233 .- 1654-1103. ; 19:6, s. 789-798
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Tidskriftsartikel (refereegranskat)abstract
- Question: To what extent do tree growth, mortality, and long-term disturbance patterns affect stand structure and composition of an old-growth Picea abies forest?Location: Boreal Sweden.Methods: We linked data from three 50 m × 50 m permanent plots established in 1986 with dendrochronology data to evaluate tree growth and mortality over an 18-year period and to describe a several-hundred-year disturbance history for this forest type.Results: Averaged over all diameters, P. abies trees had an annual mortality rate of 0.60%; however, diameter had a striking effect on both growth and mortality, with trees of intermediate diameters (ca. 20–30 cm) showing faster growth and lower mortality. Their increased vigor gave rise to a diameter distribution resembling the ‘rotated sigmoid’ (not reverse-J) proposed for such conditions, and it led to a deficit of snags of intermediate diameters. Slow-growing trees had an increased likelihood of dying. Although recruitment occurred in most decades over the past 400 years, two prominent recruitment peaks occurred (mid 1700s and 1800s), neither of which appeared to cause a shift in tree species composition. The lack of fire evidence suggests that fire was not responsible for these recruitment peaks.Conclusions: Taken together, these results depict a rather impassive system, where canopy trees die slowly over decades. Field observations suggest that fungal infections, mediated by wind, account for much of the mortality during these periods of relative quiescence. However, these periods are at times punctuated by moderate-severity disturbances that foster abundant recruitment.
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| 19. |
- Fraver, Shawn, et al.
(författare)
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Tree growth and competition in an old-growth Picea abies forest of boreal Sweden : influence of tree spatial patterning
- 2014
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Ingår i: Journal of Vegetation Science. - : Wiley. - 1100-9233 .- 1654-1103. ; 25:2, s. 374-385
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Tidskriftsartikel (refereegranskat)abstract
- Question What factors best characterize tree competitive environments in this structurally diverse old-growth forest, and do these factors vary spatially within and among stands? Location Old-growth Picea abies forest of boreal Sweden. Methods Using long-term, mapped permanent plot data augmented with dendrochronological analyses, we evaluated the effect of neighbourhood competition on focal tree growth by means of standard competition indices, each modified to include various metrics of trees size, neighbour mortality weighting (for neighbours that died during the inventory period), and within-neighbourhood tree clustering. Candidate models were evaluated using mixed-model linear regression analyses, with mean basal area increment as the response variable. We then analysed stand-level spatial patterns of competition indices and growth rates (via kriging) to determine if the relationship between these patterns could further elucidate factors influencing tree growth. Results Inter-tree competition clearly affected growth rates, with crown volume being the size metric most strongly influencing the neighbourhood competitive environment. Including neighbour tree mortality weightings in models only slightly improved descriptions of competitive interactions. Although the within-neighbourhood clustering index did not improve model predictions, competition intensity was influenced by the underlying stand-level tree spatial arrangement: stand-level clustering locally intensified competition and reduced tree growth, whereas in the absence of such clustering, inter-tree competition played a lesser role in constraining tree growth. Conclusions Our findings demonstrate that competition continues to influence forest processes and structures in an old-growth system that has not experienced major disturbances for at least two centuries. The finding that the underlying tree spatial pattern influenced the competitive environment suggests caution in interpreting traditional tree competition studies, in which tree spatial patterning is typically not taken into account. Our findings highlight the importance of forest structure - particularly the spatial arrangement of trees - in regulating inter-tree competition and growth in structurally diverse forests, and they provide insight into the causes and consequences of heterogeneity in this old-growth system.
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| 20. |
- Gärdenfors, Ulf, et al.
(författare)
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Swedish LifeWatch ─ a biodiversity infrastructure integrating and reusing data from citizen science, monitoring and research
- 2014
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Ingår i: Human Computation. - : Human Computation Institute. - 2330-8001. ; 1, s. 147-163
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Tidskriftsartikel (refereegranskat)abstract
- With continued pressure on biodiversity and ever-growing conflicts with human development, qualified systems for scenario modelling, impact assessment and decision support are urgently needed. Such systems must be able to integrate complex models and information from many sources and do so in a flexible and transparent way. To that end, as well as for other complicated and data-intensive biodiversity research purposes, the concept of LifeWatch has emerged. The idea of LifeWatch is to construct e-infrastructure and virtual laboratories by integrating large data sources, computational capacities, and tools for analysis and modelling in an open, serviceoriented architecture. To be efficient and accurate, a continuous inflow of large quantities of data is essential. However, even with new techniques, government-funded monitoring data and research data will not feed the system with up-to-date species information of sufficient scale and resolution. To fill this void, skilled amateur observers (citizen scientists) can contribute to a very valuable extent. After a preparatory phase, a Swedish LifeWatch (SLW) consortium was initiated in 2011. Swedish LifeWatch developed an infrastructure where all components are accessible through open web services. At the SLW Analysis portal, different formats of species and environmental data can be accessed instantly, and integrated, analysed, visualized and downloaded at selected temporal, spatial or taxonomic scales. Swedish LifeWatch currently provides 46 million species observations from eight different databases, all harmonized according to standardized formats and the Dyntaxa taxonomic backbone database. Almost 40 million of these observations were provided by citizens through the online reporting system named the Species Observation System (SOS) or Artportalen. This paper describes this system, as well as the incentives that make it so successful. The citizen science data in the SOS are accessible, together with data from research and monitoring, in the SLW infrastructure, making the latter a powerful instrument for large-scale data extraction, visualization and analysis.
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| 21. |
- Göransson, Hans, et al.
(författare)
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Do oaks have different strategies for uptake of N, K and P depending on soil depth?
- 2007
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Ingår i: Plant and Soil. - : Springer Science and Business Media LLC. - 0032-079X .- 1573-5036. ; 297:1-2, s. 119-125
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Tidskriftsartikel (refereegranskat)abstract
- The uptake of nutrients from deep soil layers has been shown to be important for the long-term nutrient sustainability of forest soils. When modelling nutrient uptake in forest ecosystems, the nutrient uptake capacity of trees is usually defined by the root distribution. However, this leads to the assumption that roots at different soil depths have the same capacity to take up nutrients. To investigate if roots located at different soil depths differ in their nutrient uptake capacity, here defined as the nutrient uptake rate under standardized conditions, a bioassay was performed on excised roots (< 1 mm) of eight oak trees (Quercus robur L.). The results showed that the root uptake rate of Rb-86(+) (used as an analogue for K+ stop) declined with increasing soil depth, and the same trend was found for NH4+. The root uptake rate of H2PO4-, on the other hand, did not decrease with soil depth. These different physiological responses in relation to soil depth indicate differences in the oak roots, and suggest that fine roots in shallow soil layers may be specialized in taking up nutrients such as K+ and NH4+ which have a high availability in these layers, while oak roots in deep soil layers are specialized in taking up other resources, such as P, which may have a high availability in deep soil layers. Regardless of the cause of the difference in uptake trends for the various nutrients, these differences have consequences for the modelling of the soil nutrient pool beneath oak trees and raise the question of whether roots can be treated uniformly, as has previously been done in forest ecosystem models.
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| 22. |
- Hekkala, Anne-Maarit, et al.
(författare)
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Habitat heterogeneity is a good predictor of boreal forest biodiversity
- 2023
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Ingår i: Ecological Indicators. - : Elsevier BV. - 1470-160X .- 1872-7034. ; 148
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Tidskriftsartikel (refereegranskat)abstract
- Reliable assessment measures are crucial for tracking changes in biodiversity and for evaluating the state of biodiversity. Two of the main drivers of biodiversity are habitat heterogeneity and resource amount. These drivers are used as proxies of biodiversity but assessing both is costly, limiting their practical use. To test which of the drivers best predicts the number and abundance of sessile species of conservation concern (including macrofungi, lichens, bryophytes, and vascular plants), we assessed forest stand heterogeneity using a method developed in Sweden ('Habitat Heterogeneity Score HHS'), and quantified the resource amount and quality of ecologically important structural variables (deadwood volume, basal area of living trees, proportion of broadleaved trees, and the age of the oldest tree in the stand). We conducted the assessments in 77 boreal coniferdominated forest stands in two regions of Sweden. Despite some group-specific organism differences, HHS was the best predictor of both number and abundance of all species of conservation concern, regardless of the region. Further, HHS was the best predictor of red-listed species number and abundance in the southern region, while a model including the volume of deadwood and the age of the oldest tree performed best in the northern region. Deadwood (CWD) volume was the single best resource amount predictor of the number and abundance of species of conservation concern, emphasizing the critical role that dead trees have for biodiversity. In addition, we calculated threshold values for deadwood volume and HHS depicting the level above which the number of red-listed species is significantly higher, and found this value to be higher in the southern region (22.4 m(3) ha(-1) deadwood and a HSS value of 17) than in the north (20.0 m(3) ha(-1) and 16). These values can be used as guidance when identifying coniferous forests with high enough qualities to support red-listed species. To conclude, the method of assessing habitat heterogeneity presented in this study is a practical and reliable way to identify forests of high biological diversity, and can therefore be part of the toolbox for sustainable forestry in boreal forests.
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| 23. |
- Henckel, Laura, et al.
(författare)
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Assessing the usefulness of citizen science data for habitat suitability modelling: Opportunistic reporting versus sampling based on a systematic protocol
- 2020
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Ingår i: Diversity and Distributions. - : Wiley. - 1366-9516 .- 1472-4642. ; 26, s. 1276-1290
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Tidskriftsartikel (refereegranskat)abstract
- Aim To evaluate the potential of models based on opportunistic reporting (OR) compared to models based on data from a systematic protocol (SP) for modelling species distributions. We compared model performance for eight forest bird species with contrasting spatial distributions, habitat requirements and rarity. Differences in the reporting of species were also assessed. Finally, we tested potential improvement of models when inferring high-quality absences from OR based on questionnaires sent to observers. Location Both datasets cover the same large area (Sweden) and time period (2000-2013). Methods Species distributions were modelled using logistic regression. Predictive performance of OR models to predict SP data was assessed based on AUC. We quantified the congruence in spatial predictions using Spearman's rank correlation coefficient. We related these results to species characteristics and reporting behaviour of observers. We also assessed the gain in predictive performance of OR models by adding inferred absences. Finally, we investigated the potential impact of sampling bias in OR. Results For all species, and despite the sampling biases, results from OR overall agreed well with those of SP, for the nationwide spatial congruence of habitat suitability maps and the selection and directions of species-environment relationships. The OR models also performed well in predicting the SP data. The predictive performance of the OR models increased with species rarity and even outperformed the SP model for the rarest species. No significant impact of observer behaviour was found. Main conclusions Relatively simple analyses with inferred absences could produce reliable spatial predictions of habitat suitability. This was especially true for rare species. OR data should be seen as a complement to SP, as the weakness of one is the strength of the other, and OR may be especially useful at large spatial scales or where no systematic data collection protocols exist.
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