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- Bakx, Tristan
(författare)
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A window into forest landscapes : Studying the relationship between forests, ownership, ecosystem services, and biodiversity in landscapes
- 2024
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Production forests are faced with the challenge of adapting to environmental change and simultaneously helping mitigate it and host rich biodiversity. This leads to new conflicts and trade-offs for forest management. Many management options have been proposed to achieve these goals while minimizing the loss of timber production. In this thesis, I explore the status and future of forest landscapes through multiple disciplines including physical geography, ecology, and forestry. Across landscapes, solutions for increased sustainability can be limited by the distribution and size of non-industrial privately-owned forest (NIPF) properties. At the national scale, it is important to prioritize the parts of the country where environmental measures should be focused. In my thesis, I studied different aspects of the relation between Swedish forests and spatial and temporal scale within the context of forest sustainability. I studied how NIPF properties could be classified by the characteristics of the forest within them. I also investigated how this characterization related to characteristics of the owner such as gender and age. Many forest properties were still significantly shaped by storm damage from over 15 years earlier. The diversity of forests that NIPF owners have presents each owner with a different challenge to adapt to a changing environment. This landscape diversity can affect the possibility of NIPF owners to implement environmental considerations in management. To illustrate this, I showed that forest owners with large properties can store more carbon in their forest at a lower cost than owners with little forest. Additionally, introducing carbon sequestration targets in forestry to aid mid-century climate mitigation efforts could be particularly costly for forest owners. Furthermore, the distribution of streams in a forest landscape will affect the amount of forest land that owners have to set-aside to protect those streams. I showed that the cost of implementing those buffer zones is unequally distributed among forest owners and that this inequality is largest among owners with small forests. The benefits of economies of scale can be explained by the positive relationship between spatial scale and landscape heterogeneity. Future policies should take this relationship into account to effectively persuade forest owners to increase the sustainability of their forests. Finally, I evaluated whether a proposed prioritization of Swedish landscapes for future conservation measures can target specialist and threatened forest birds. The proposed scheme mainly covered specialist forest birds in Northern Sweden and appropriate conservation measures could benefit those species. In other parts of Sweden, additional prioritizations are needed to provide sufficient opportunities to protect forest biodiversity. Overall, this thesis shows how the heterogeneity within and between forest landscapes influences the potential to increase sustainability for different environmental targets in forest management in Sweden. The understanding of the spatial distribution of forest properties, the spatiotemporal scale of management, and interactions between forestry objectives are all essential for solving the environmental puzzle that 21st-century forestry faces.
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| 2. |
- Bakx, Tristan, et al.
(författare)
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Areas of high conservation value support specialist forest birds
- 2023
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Ingår i: Ecosphere. - 2150-8925. ; 14:6
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Tidskriftsartikel (refereegranskat)abstract
- Scientists have deemed existing protected areas in European forests insufficient to halt and reverse biodiversity loss resulting from ongoing intensification of management. In Sweden, protected areas are therefore complemented with the so-called areas of high conservation value (AHCVs), that is, landscapes encompassing both protected and assumed biodiversity-valuable areas as well as surrounding land, where managers should pay increased attention to biodiversity. However, it is not known whether AHCVs are chosen so that the species they are intended to benefit inhabit such AHCVs to a higher degree. We investigated whether the occurrence and abundance of bird species that may be particularly vulnerable to intense forest management were higher in Swedish forest landscapes proposed as AHCVs compared with other forest landscapes. To this end, we fitted a joint species distribution model to bird count data for 70 forest bird species from a standardized Swedish bird monitoring scheme. Twelve of the 20 forest specialists (60%) were detected to occur more often inside AHCVs than outside, whereas no forest specialist was less likely to occur inside AHCVs. For forest generalists, the corresponding figures were 28% and 18%, respectively. Six of 15 red-listed species (40%) were detectably more likely to occur inside AHCVs. The relationship between AHCV status of landscapes and the abundance of individual species was not as consistently negative or positive. The higher occurrence of specialists and threatened species inside AHCVs than outside of them suggests that if managed correctly, AHCVs are important habitat for a considerable part of the specialized forest avifauna in Sweden. We conclude that AHCVs represent an opportunity for designing green infrastructure benefitting Swedish forest biodiversity.
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| 3. |
- Bakx, Tristan R.M., et al.
(författare)
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Farmland birds occupying forest clear-cuts respond to both local and landscape features
- 2020
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Ingår i: Forest Ecology and Management. - : Elsevier BV. - 0378-1127. ; 478
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Tidskriftsartikel (refereegranskat)abstract
- Agricultural landscapes have changed fast in Europe, which has led to steep declines in farmland biodiversity. While this has differentially impacted “farmland species”, some of these seem to be able to use alternative man-made open habitats in forests, such as forest clear-cuts and powerline rights-of-way. We investigated the use of clear-cuts by two historically declining farmland birds, the Yellowhammer (Emberiza citrinella) and the Red-backed Shrike (Lanius collurio), to determine both local and landscape habitat characteristics of clear-cuts used for breeding. Among 101 clear-cuts visited in Scania, southern Sweden, 27% were occupied by Yellowhammers and 12% by Red-backed Shrikes. Yellowhammer occurrence in clear-cuts was positively related to local spruce cover (the planted tree species). There was also an interaction between clear-cut size and the proportion of farmland in the landscape, such that the positive effect of the proportion of farmland nearby was stronger for larger clear-cuts. Red-backed Shrike occurrence was positively related to clear-cut size and the local presence of piles of forest residues (tops and branches). The relation between occurrence and the proportion of clear-cuts in the landscape was positive for small clear-cuts and negative for larger ones. Yellowhammers and Red-backed shrikes are affected by both the local habitat structure in the clearcut and on the composition of the surrounding landscape, most likely because they use the clear-cut for nesting and the surroundings as complementary feeding habitat. To what extent clear-cuts as complementary breeding habitat to farmland may contribute to the conservation of Yellowhammers and Red-backed shrikes, as well as other farmland birds, is a promising path for future investigations.
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| 4. |
- Bakx, Tristan R.M., et al.
(författare)
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Riparian buffer zones in production forests create unequal costs among forest owners
- 2024
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Ingår i: European Journal of Forest Research. - 1612-4669. ; 143:3, s. 1035-1046
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Tidskriftsartikel (refereegranskat)abstract
- Riparian buffer zones (RBZs) are an important instrument for environmental policies for water and biodiversity protection in managed forests. We investigate the variation of the cost of implementing RBZs within different property size classes across the size range of non-industrial forest owner properties in Southern Sweden. Using the Heureka PlanWise decision support system, we quantified the cost of setting aside RBZs or applying alternative management in them, as the relative loss of harvest volume and of net present value per property. We did this for multiple simulated as well as real-world property distributions. The variation of cost distribution among small properties was 4.2–6.9 times higher than among large properties. The interproperty cost inequality decreased non-linearly with increasing property size and levelled off from around 200 ha. We conclude that RBZs, due to the irregular distribution of streams, cause highly unequal financial consequences for owners, with some small property owners bearing a disproportionally high cost. This adds to previous studies showing how environmental considerations differentially affect property owners. We recommend decision makers to stimulate the uptake of RBZs by alleviating these inequalities between forest owners by including appropriate cost sharing or compensation mechanisms in their design.
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| 5. |
- Bakx, Tristan R.M., et al.
(författare)
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The effect of spatial and temporal planning scale on the trade-off between the financial value and carbon storage in production forests
- 2023
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Ingår i: Land Use Policy. - : Elsevier BV. - 0264-8377 .- 1873-5754. ; 127
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Tidskriftsartikel (refereegranskat)abstract
- Background: Increasing carbon stock in standing forests is one of the proposed ways to mitigate climate change. However, in production forests, this typically would lead to reduced harvesting possibilities and thus reduced financial gain for the forest owners. The size of this reduction should depend on the chosen target level of the carbon stock as well as the required speed of accumulation. Furthermore, due to landscape heterogeneity, the size of the loss can be expected to vary the planning scale, often related to forest property size. Aim: This study aimed to quantify the effects of spatial and temporal planning scales on the severity of the trade-off between Net Present Value (NPV) of future timber sales and carbon storage in production forests in Southern Sweden. Methods: We used the Heureka PlanWise forest decision support system with built-in Linear Programming functionality. We created six Production Possibility Frontiers (PPF) that quantified the trade-off for the combinations of two scenarios for timing of carbon accumulation (either by 2100 or by 2100 with an intermediate target by 2045) and three spatial management scales (∼3300 ha, ∼300 ha, and ∼60 ha; 1068 stands). Results: There was a strong effect of temporal scale, with consistently lower NPV, with the same carbon stock in 2100, when the intermediate target for 2045 was applied. The effect of the spatial scale was only apparent between the smallest (50 ha) scale and the larger scales (300 and 3300 ha), with consistently lower NPV with the same carbon stock at the smallest scale. Conclusion: We conclude that both the effects of spatial management scale and temporal scale on the cost of carbon storage should be considered in relation to potential climate policies.
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| 6. |
- Green, Martin, et al.
(författare)
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Fåglar på fågelskär i de stora sjöarna : Utvärdering av det gemensamma delprogrammet Insjöfåglar
- 2019
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- I denna rapport utvärderar vid det Gemensamma delprogrammet (GDP) Insjöfåglar, det vill säga de inventeringar av sjöfåglar under häckningstid som gjorts på fågelskär i de fyra största insjöarna i landet; Vänern, Vättern, Mälaren och Hjälmaren. Inventeringarna har genomförts i regi av läns-styrelserna kring sjöarna och sjöarnas Vattenvårdsförbund. Huvudfokus i rapporten ligger på populationstrender för utvalda sjöfågelarter för respektive sjö, samt för alla sjöar gemensamt.Inventeringar av fåglar på fågelskär har skett under olika lång tid i de olika sjöarna. Först ut var Vänern där heltäckande inventeringar av fåglar på fågelskär pågått sedan 1994 och nu därmed under 25 år. Därefter kom inventeringar igång i Vättern 2002, i Mälaren år 2005 och i Hjälmaren år 2015. Vi kan därför beskriva 25-årstrender från Vänerns fågelskär, 17-års-trender för Vätterns fågelskär och trender över 14 år för Mälarens fågelskär. För Hjälmarens fågelskär kan vi ännu inte beräkna några trender, men detta kommer att bli möjligt när minst fem inventeringsår har genomförts. För de stora sjöarna gemensamt går det att beräkna populationstrender för hela den period varifrån det finns inventeringar från någon av sjöarna, det vill säga samma 25-årsperiod som för Vänern. Detta genom att vi använder avancerad statistik som kan ta hänsyn till att det inte inventerats under lika lång period i alla sjöarna.Vi presenterar trender för 29 olika fågelarter totalt sett. För de enskilda sjöarna är antalet arter som det går att presentera en trend för lägre. Från Vänern visar vi trender för 28 arter 1994–2018, från Vättern för 19 arter 2002–2018 och från Mälaren för 22 arter 2005–2018. I långtidsperspektivet 1994–2018 har utvecklingen för fåglar på fågelskär i de stora sjöarna generellt varit positiv. Under denna period har 18 arter statistiskt säkra ökningar och fem arter statistiskt säkra minskningar i alla sjöarna gemensamt. Sex arter uppvisar inga säkerställda förändringar. I de enskilda sjöarna, för de perioder som täcks här är mönstren mer varierande. Allmänt sett har utvecklingen varit mer positiv i Vänern och Vättern än i Mälaren. I det kortare tidsperspektivet där inventeringar finns från de tre största sjöarna är mönstren inte lika positiva. Under den perioden uppvisar nio arter positiva trendriktningar, 15 arter negativa trendriktningar och fem arter visar inga tecken på tydliga förändringar i sjöarna sammantaget.Vi presenterar även förslag på möjliga miljömålsindikatorer baserade på data från programmet. Detta i form av trender för den samlade populations-utvecklingen för olika arturval. Vi rekommenderar i första hand att ett urval som innehåller arter som hämtar all eller huvuddelen av sin föda i sjöarna används som indikatorer. Detta då sådana indikatorer allra bäst bör spegla sjöarnas miljötillstånd. De framräknade indikatorerna bekräftar bilden som ges ovan genom att utvecklingen i Vänern till synes har varit mer positiv än i de andra sjöarna. I korttidsperspektivet är skillnaderna mellan sjöarna mindre.I rapporten tar vi även en allra första titt på fågeldata från fågelskären i jämförelse med resultat från de provfisken som gjorts i sjöarna. Resultaten är varierande, men i några fall finner vi de förväntade sambanden att det finns fler fiskätande fåglar i delområden där det finns mer fisk. Vi rekommenderar mer avancerade och detaljerade analyser av sambanden mellan fågeldata och andra data som på ett eller annat sätt beskriver sjöarna miljötillstånd och/eller andra former av biodiversitet i sjöarna. Vi tror att den typen av analyser kan bidra till en ökad förståelse av de olika ekologiska samband som finns i sjöarna och av hur och på vilka sätt som sjöarnas miljötillstånd varierar.Vi gör bedömningen att det mesta när det gäller själva upplägget och fältarbetet inom GDP Insjöfåglar fungerar alldeles utmärkt och bör fortsätta på i stort samma sätt framöver. Vi ser däremot en del brister när det gäller den datahantering som skett hittills och rekommenderar därför en översyn och samordning mellan ingående sjöar på det området. En sådan samordning bör ske inom ramarna för och i samarbete med den datavärd som programmet väljer att ansluta sig till.
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