| 1. |
- Braun, Sabine, et al.
(författare)
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Nitrogen deposition in forests: Statistical modeling of total deposition from throughfall loads
- 2022
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Ingår i: Frontiers in Forests and Global Change. - : IVL Svenska Miljöinstitutet. - 2624-893X. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Nitrogen (N) gradient studies in some cases use N deposition inthroughfall as measure of N deposition to forests.For evaluating critical loadsof N, however, information on total N deposition is required, i.e., the sum ofestimates of dry, wet and occult deposition.Methods: The present paper collects a number of studies in Europe wherethroughfall and total N deposition were compared in different forest types.From this dataset a function was derived which allows to estimate total Ndeposition from throughfall N deposition.Results: At low throughfall N deposition values, the proportion of canopyuptake is high and thus the underestimation of total deposition by throughfallN needs to be corrected.At throughfall N deposition values > 20 kg Nha?1 yr?1 canopy uptake is getting less important.Conclusion: This work shows that throughfall clearly underestimates totaldeposition of nitrogen. With the present data set covering large parts of Europe it is possible to derive a critical load estimate from gradient studiesusing throughfall data.
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| 2. |
- Lopes, Gabriela Russo, et al.
(författare)
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Understanding deforestation lock-in : Insights from Land Reform settlements in the Brazilian Amazon
- 2022
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Ingår i: Frontiers in Forests and Global Change. - : Frontiers Media SA. - 2624-893X. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- Cropland and pasture expansion continues to erase natural ecosystems at a staggering speed globally, notably in the tropics. Conventional policy approaches, usually focused on a particular land-use change driver (e.g., specific commodities) or individual regulations (e.g., the Amazon Soy Moratorium), have consistently failed to achieve sufficient or sustained results. The swift reversal of Brazil’s earlier success in reducing Amazon deforestation – now again accelerated – offers perhaps the most sobering illustration of that. Therefore, this article draws from scholarship on sustainability transitions to propose a more comprehensive systems view of unsustainable land-use patterns. We examine persistent tropical deforestation as a case of “lock-in,” using a transitions lens, and explore its constitutive elements. As a case study, we analyze the situation of Land Reform settlements in the Brazilian Amazon, where as much as one-third of that biome’s deforestation takes place. While subject to some specific factors, those places are also enmeshed in a broader setting that is common across the Brazilian Amazon’s deforestation frontier (e.g., infrastructure conditions, market demands, and sociocultural norms). Drawing from document analysis of Brazilian policies and fieldwork in three Land Reform settlements in Pará State, we expose multiple forms of techno-economic, institutional, and socio-cognitive lock-in that together drive deforestation systemically in those settlements. These drivers form a strongly consolidated socio-technical regime around large-scale agriculture that includes material and immaterial factors (e.g., cultural ones), a regime that not only resists change but also – like a vortex – pulls others into it. Escaping deforestation lock-in may thus require outside forces to help local actors destabilize and eventually replace this unsustainable land-use regime. International zero-deforestation efforts offer a starting point, but a transition requires moving beyond piecemeal, incremental change or end-of-pipe approaches and toward concerted, strategic action that addresses multiple of those regime elements in a coordinated way to replace it as a system. We argue that understanding deforestation lock-in is vital for tackling its worrisome persistence and that sustainability transitions theory offers an illuminating, but still underutilized, framework to analyze and eventually overcome unsustainable land use.
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| 3. |
- Snäll, Tord
(författare)
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Impacts of Forest Management on Forest Bird Occurrence Patterns-A Case Study in Central Europe
- 2022
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Ingår i: Frontiers in forests and global change. - : Frontiers Media SA. - 2624-893X. ; 05
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Tidskriftsartikel (refereegranskat)abstract
- The global increase in demand for wood products, calls for a more sustainable management of forests to optimize both the production of wood and the conservation of forest biodiversity. In this paper, we evaluate the status and future trends of forest birds in Central European forests, assuming different forest management scenarios that to a varying degree respond to the demand for wood production. To this end, we use niche models (Boosted Regression Trees and Generalized Linear Models) to model the responses of 15 forest bird species to predictors related to forest stand (e.g., stand volume of specific tree species) and landscape structure (e.g., percentage cover), and to climate (bioclimatic variables). We then define five distinct forest management scenarios, ranging from set-aside to productivity-driven scenarios, project them 100 years into the future, and apply our niche models into these scenarios to assess the birds' responses to different forest management alternatives. Our models show that the species' responses to management vary reflecting differences in their ecological niches, and consequently, no single management practice can benefit all species if applied across the whole landscape. Thus, we conclude that in order to promote the overall forest bird species richness in the study region, it is necessary to manage the forests in a multi-functional way, e.g., by spatially optimizing the management practices in the landscape.
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| 4. |
- Tunlid, Anders, et al.
(författare)
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Decomposition of soil organic matter by ectomycorrhizal fungi : Mechanisms and consequences for organic nitrogen uptake and soil carbon stabilization
- 2022
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Ingår i: Frontiers in Forests and Global Change. - : Frontiers Media SA. - 2624-893X. ; 5
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Forskningsöversikt (refereegranskat)abstract
- A major fraction of nitrogen (N) in boreal forest soils is found in organic forms associated with soil organic matter (SOM) and mineral particles. The capacity of ectomycorrhizal (ECM) fungal symbionts to access this N is debated, considering that these fungi have lost many of the genes for decomposing organic matter that were present in their saprotrophic ancestors. To gain a molecular-level understanding of the N-mining processes in ECM fungi, we developed an experimental approach where the processes of decomposition were studied in parallel with the changes in the structure and properties of the organic matter. We showed that ECM fungi have significant capacities to assimilate organic N associated with SOM and mineral surfaces. The decomposition mechanisms differ between species, reflecting the lignocellulose decomposition mechanisms found in their saprotrophic ancestors. During N-mining, the ECM fungi processed the SOM to a material with increased adsorptive properties to iron oxide mineral particles. Two pathways contributed to these changes: Extracellular modifications of the SOM and secretion of mineral surface reactive metabolites. Some of these metabolites have iron(III)-reducing activities and can participate in extracellular Fenton reactions and redox reactions at iron oxide mineral surfaces. We conclude that the traditional framework for understanding organic N acquisition by ECM fungi from recalcitrant SOM must be extended to a framework that includes how those decomposition activities affect the stabilization and reactivity of mineral-associated SOM. The activity through these complex networks of reactions is decisive for the overall effect of ECM fungal decomposition on nutrients and C-cycling in forest ecosystems.
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| 5. |
- Yong, Jean W.H
(författare)
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When nature needs a helping hand: different levels of human intervention for mangrove (re-)establishment
- 2022
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Ingår i: Frontiers in forests and global change. - : Frontiers Media SA. - 2624-893X. ; 5
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Forskningsöversikt (refereegranskat)abstract
- Protecting existing mangrove forests is a priority for global conservation because of the wide range of services that these coastal forests provide to humankind. Despite the recent reduction in global rates of mangrove loss, high historical loss rates mean that there are at least 800,000 ha globally that are potentially suitable for mangrove rehabilitation. Recently deposited mud banks or intertidal, previously terrestrial, land might provide additional habitat for expanding mangrove areas locally. There is a long history of mangrove rehabilitation. However, despite numerous good examples of, and growing expertise in, natural or assisted (re-)establishment activities, most mangrove planting efforts, for instance, either fail entirely or meet with only limited success. Exposed to waves and currents and subject to tidal inundation, mangroves differ from terrestrial forests, and approaches to, or tools for, terrestrial forest restoration cannot easily be transferred to mangrove forests. Successful mangrove (re-)establishment usually requires a robust understanding of the abiotic and biotic conditions of the chosen site, the ecological requirements of the mangrove species used or facilitated, the reasons for previous mangrove loss or degradation, as well as the barriers – both societal and ecological – that have prevented natural recovery to date. Because most mangrove forests are socio-ecological systems, with which local human populations are intimately engaged, (re-) establishment will normally require the support of, and engagement with, local communities and other local stakeholders. Here, we summarize where, when and why (re-)establishment of mangroves is needed and how to assess this need. We discuss a range of potential aims and goals of mangrove (re-)establishment along with potential pitfalls along the way from conceiving the initial idea to its realization. We compare different technical and conceptual approaches to mangrove (re-)establishment, their challenges and opportunities, and their design and financial requirements, as well as potential solutions. We ground our final outlook and recommendations on examples of successful efforts and the factors that rendered (re-)establishment successful in the past.
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