Deadwood Biodiversity

Deadwood is a key component for biodiversity and ecosystem services in boreal forests; however, the abundance of this critical element is declining worldwide. In natural forests, deadwood is produced by tree death due to physical disturbances, senescence, or pathogens. Timber harvesting, fire suppression, and salvage logging reduce deadwood abundance and diversity, and climate change is expected to bring further modifications. Although the effects of these changes are not yet fully understood, restoring a continuous supply of deadwood in boreal forest ecosystems is vital to reverse the negative trends in species richness and distribution. Increasing the availability of deadwood offers a path to building resilient forest ecosystems for the future

Wildfire and prescribed burning impact moose forage availability and browsing levels in the northern boreal forest

Fire regimes and herbivore densities have in parts of the boreal been heavily impacted by human activities with consequences for vegetation, forage supply and ungulate use. In this study, we evaluate the effects of natural wildfires and prescribed burning on moose forage availability, use, and browsing in northern Sweden. We studied three wildfire locations, adjacent controls, and five prescribed burns 12 years after fire. To compare forage availability and browsing levels we combined related variables with Principal Component Analyses and used the first axis in a regression analysis. The wildfire locations had a different composition of forage compared with the controls with less forage in the field layer and more woody browse and deciduous saplings. Forage availability was best explained by the occurrence of fire and differed between wildfire and the unburned control areas. Browsing levels were higher in wildfire locations compared with unburned controls. Prescribed burns varied substantially and could resemble both unburnt control and wildfire in terms of forage availability and browsing. We conclude that prescribed burning as a restoration action potentially can improve forage availability, particularly of deciduous species, if they mimic the impact of wildfires in terms of larger area burned and high fire severity

Wildfire yields a distinct turnover of the beetle community in a semi-natural pine forest in northern Sweden

Background Fires have been an important natural disturbance and pervasive evolutionary force in the boreal biome. Yet, fire suppression has made forest fires rare in the managed landscapes in Fennoscandia, causing significant habitat loss for saproxylic species such as polypores and insects. To better understand how the beetle community changes (species turnover) after a wildfire in a landscape with intense fire suppression, we monitored beetles with flight intercept traps the first 3 years as well as 12 years after a large wildfire in a national park in northern Sweden (a control/unburnt area was set up for the last year of sampling). Results Species composition changed significantly among all studied years with a continuous turnover of species following the wildfire. The indicator species analysis showed that year 1 post-fire was mostly associated with cambium consumers and also the pyrophilous speciesBatrisodes hubenthali. Year 2 was the most abundant and species-rich year, withTomicus piniperdaas the most important indicator species. The indicator species year 3 were mostly secondary successional species, fungivores, and predators and were characterized by lower species diversity. Year 12 had higher diversity compared with year 3 but lower species richness and abundance. A control area was established during year 12 post-fire, and our analyses showed that the control area and burned area differed in species composition suggesting that the beetle community needs longer than 12 years to recover even after a low-intensive ground fire. Conclusion The wildfire area hosted several red-listed and fire-dependent species suggesting that after a century of landscape-level fire suppression in a semi-natural area, the reintroduction of fire benefits rare and pyrophilous species and still impacts species composition after 12 years. This study implies that fire has long-lasting effects on high latitudes and that prescribed burning has the potential to benefit biodiversity over decades in these landscapes while also highlighting the value of considering the whole species community and not only monitoring abundance and richness to assess biodiversity after management actions

Reinventory of permanent plots show that kelo lichens face an extinction debt

Intensive forestry has led to landscape level deficits of important substrates such as deadwood and its associated biodiversity. Several taxa face extinction debts due to continuous declines and lack of regeneration of important habitats. Deadwood-dependent lichens are of great conservation concern due to a general lack of deadwood and due to their slow establishment, especially of rare species. In a field restoration experiment in central Sweden, we studied deadwood-dependent lichens for eight years, their association to different types of deadwood and their response to environmental change caused by variable retention forestry, deadwood enrichment and prescribed burning. Prescribed burning and site preparation caused depauperate lichen species assemblages throughout the study period but retention felling did not majorly affect lichen species assemblages. We found that lichen species were nested along deadwood qualities and deadwood created in the experiment only hosted a subset of lichen species found on kelo wood. Despite large reductions of kelo wood with lichen occurrences over the study period, overall species richness did not decrease. The fact that a large part of the lichen community occur only on kelo wood and that kelo wood is not regenerated implies that lichens associated with kelo wood face an extinction debt. In order to avoid local extinctions of deadwood-dependent lichens, site preparation and prescribed burning should be avoided in areas rich in high quality deadwood. There is urgent need to start creating new kelo wood through reoccurring fires in order to halt the impending extinction debt

A decadal study reveals that restoration guided by an umbrella species does not reach target levels

Maintaining structural and functional elements of ecosystems are essential in order to preserve biodiversity and ecosystem function. As a means of guiding conservation work, the umbrella species concept was developed. In Sweden, one putative umbrella species, the white-backed woodpecker, has guided conservation and restoration of deciduous forests for two decades. Here, we evaluate the decadal effects of restoration aimed at the white-backed woodpecker on biodiversity of saproxylic beetles. We compare stands that were restored 12 to 21 years ago to non-restored stands and historical white-backed woodpecker habitats acting as restoration target stands. Restored stands contained higher deciduous deadwood volumes than non-restored stands but lower volumes than restoration target stands. The deadwood in restored stands was concentrated in later decay stages, whereas target stand deadwood was more evenly distributed across decay stages. Restored stands had similar species richness and abundance of most groups of saproxylic beetles compared with non-restored stands while not reaching the levels of restoration target stands. Species assemblages differed among all stand types with restored stands supporting late decay stage and generalist species while target stands supported more deciduous associated and threatened species. Synthesis and applications: We conclude that after one to two decades, restoration improve stand structure and benefit beetle diversity but that target levels are not yet reached. Thus, only partial restoration is achieved. Our results stress that for restoration to be successful both continuous and repeated restoration efforts are needed and that it is important to identify target levels of important habitat characteristics when assessing restoration outcome.We conclude that after one to two decades, restoration improve stand structure and benefit beetle diversity but that target levels are not yet reached. Thus, only partial restoration is achieved. Our results stress that for restoration to be successful both continuous and repeated restoration efforts are needed and that it is important to identify target levels of important habitat characteristics when assessing restoration outcome. imag

Bryophyte species composition at the stand scale (1 ha) – Differences between secondary stands half a century after clear-cutting and older semi-natural boreal forests

A growing proportion of the boreal biome consists of managed even-aged secondary forest stands regenerated after clear-cutting. Many disturbance-intolerant species may not be able to recolonize or reach their original abundance in these stands before the next clear-cutting, potentially causing large-scale biodiversity losses. Boreal bryophytes (mosses and liverworts) include many species intolerant to clear-cutting, and at small spatial scales species richness and occupancy has been shown to remain changed in secondary stands half a century after logging. To assess if such persistent changes occur also at the stand scale, we listed and estimated cover of all bryophyte species in 1-ha plots, comparing 14 secondary stands originating from clear-cutting 40–60 years earlier with 14 older semi-natural stands. The large plots also made it possible to assess differences in occupancy and abundance for more bryophyte species than in previous studies. Species composition differed significantly for both mosses and liverworts, but unlike earlier studies, we could not detect any significant difference between stand types in species numbers. Thirteen species were significantly associated with semi-natural stands and the total cover of liverworts was less than half in secondary stands. Secondary stands had significantly fewer species typically occurring under shady conditions and/or mostly growing on “tree substrates” (dead wood and/or bases and stems of living trees). Ordination analysis further emphasized the importance of shade and suitable deadwood substrates; the among-plot variation in bryophyte species composition was related to amount of coarse deadwood as well as to gradients from shady spruce dominated to open pine dominated stands and from polar- to equator-facing slopes. Besides lack of suitable habitat conditions in secondary stands, dispersal limitation may have caused a colonization time lag for some species. The clear importance of stand scale habitat conditions for bryophyte species composition calls for management adaptions to facilitate life boating and/or recolonization by ensuring availability of shade, coarse decomposing logs, and specific deciduous tree species (Populus, Salix, Sorbus) in secondary stands

"Land-sparing benefits biodiversity while land-sharing benefits ecosystem services": Stakeholders' perspectives on biodiversity conservation strategies in boreal forests

Biodiversity conservation and economic profit from forests can be combined by various land-sparing and land-sharing approaches. Using a semi-structured survey, we evaluated support for scenarios representing contrasting conservation strategies in a managed boreal forest landscape. Land-sparing approaches were supported by the conservation organisation, regional administrations and the forest company, mainly motivated by the benefit for biodiversity based on ecological theory. Land-sharing approaches were supported by one recreational organisation, some municipalities and the forest owners' association, mainly motivated by the delivery of ecosystem services. Stakeholder groups using certain ecosystem services had motivations that we related to an anthropocentric mindset, while others focused more on species conservation, which can be related both to an anthropocentric or an ecocentric mindsets. Forest conservation planning should consider stakeholders' preferences to handle land-use conflicts. Since reaching consensus among multiple stakeholders seems unfeasible, a combination of land-sparing and land-sharing approaches is probably the best compromise

A decadal study reveals that restoration guided by an umbrella species does not reach target levels

<p>Maintaining structural and functional elements of ecosystems are essential in order to preserve biodiversity and ecosystem function. As a means of guiding conservation work, the umbrella species concept was developed. In Sweden, one putative umbrella species, the white-backed woodpecker, has guided conservation and restoration of deciduous forests for two decades.</p> <p>Here, we evaluate the decadal effects of restoration aimed at the white-backed woodpecker on biodiversity of saproxylic beetles. We compare stands that were restored twelve to twenty-one years ago to non-restored stands and historical white-backed woodpecker habitats acting as restoration target stands.</p> <p>Restored stands contained higher deciduous deadwood volumes than non-restored stands but lower volumes than restoration target stands. The deadwood in restored stands was concentrated in later decay stages whereas target stand deadwood was more evenly distributed across decay stages.</p> <p>Restored stands had similar species richness and abundance of most groups of saproxylic beetles compared with non-restored stands while not reaching the levels of restoration target stands. Species assemblages differed among all stand types with restored stands supporting late decay stage and generalist species while target stands supported more deciduous associated and threatened species. 5. Synthesis and applications: We conclude that after one to two decades, restoration improve stand structure and benefit beetle diversity but that target levels are not yet reached. Thus, only partial restoration is achieved. Our results stress that for restoration to be successful both continuous and repeated restoration efforts are needed and that it is important to identify target levels of important habitat characteristics when assessing restoration outcome.</p><p>Funding provided by: Swedish University of Agricultural Sciences<br>Crossref Funder Registry ID: https://ror.org/02yy8x990<br>Award Number: </p><p>Funding provided by: Stora Enso (Sweden)<br>Crossref Funder Registry ID: https://ror.org/01thwj886<br>Award Number: </p><p>Funding provided by: Stiftelsen Mauritz Carlgrens Fund*<br>Crossref Funder Registry ID: <br>Award Number: </p><p>Three IBL2, flight-intercept traps were strung between trees at breast height in a North, Southeast, Southwest pattern based on the centre of each stand, approximately 30-70 m from the stand centre. IBL2 traps are large (base 1 m, height 1m, intercept area 0.3 m3); semi-transparent flight-intercept traps shaped like downward facing triangles (Bell et al., 2015). All flying invertebrates were contained in bottles, filled to one-third with 70% propylene glycol and some detergent, at the bottom of the traps. The traps were equipped with water-diverging modules that prevent rainwater from entering and flooding the bottles. The traps were set out in the first week of June 2021 and collected in mid-October 2021. An expert taxonomist identified all saproxylic beetles to species level. We then categorised beetles based on their affiliation to deadwood, decay stage, tree species, their conservation status and if they were recorded as prey species for the white-backed woodpecker. This resulted in the following categories: a) Saproxylics, b) Saproxylic species of conservation concern, meaning that they have had the conservation status of NT or higher during the last three Swedish red lists (Gärdenfors, 2010; Swedish Species Information Centre, 2015;2020), c) WBW prey species, species pointed out as especially attractive as food for the white-backed woodpecker according to Aulén, (1988), g) Coniferous preferring, h) Deciduous preferring, i) Generalist, with no tree species preference, j) Early, species occurring at early stages of deadwood decay, k) Middle, middle decay species, l) Late, late decay species and m) decay stage generalists, with no known preferences of decay stage. The same species can occur in several groups. Classifications of ecological preferences were based on available literature (Koch, 1992; Hagge et al., 2019; Seibold et al., 2015) and personal communication with taxonomic experts; nomenclature following the Swedish Dyntaxa system (Dyntaxa, n.d.).</p> <p>Tree species and diameter at breast height (DBH, 1.3m) were recorded for all living trees higher than 1.3 m and > 5 cm in DBH within a 10 m circular sample plot at the centre of each stand. Coarse woody debris (DBH >10 cm, length/height >1.3 m) was measured within one 25 m circular sample plot, at the centre of each stand. We divided all deadwood by type (logs and snags), tree species and decay stage following Gibb et al., (2005) for logs and Jung et al., (1999) for snags. Top- and bottom diameter and length was measured for logs. For snags, we measured diameter in breast height and assessed height. Deadwood volumes for logs and snags up to 6 m height (as these snags were usually broken) were calculated as cylinders. For taller snags (>6 m) we used Brandel, (1990)'s southern Sweden volume functions for pine and spruce with birch being used for all deciduous tree species.</p&gt

Translocation of deadwood in ecological compensation: A novel way to compensate for habitat loss

Restoration of degraded habitat is frequently used in ecological compensation. However, ecological restoration suffers from innate problems of long delivery times of features shown to be good proxies for biodiversity, e.g., large dead trees. We tested a possible way to circumvent this problem; the translocation of hard-to-come deadwood substrates from an impact area to a compensation area. Following translocation, deadwood density in the compensation area was locally equivalent to the impact area, around 20 m3 ha-1, a threshold for supporting high biodiversity of rare and red-listed species. However, deadwood composition differed between the impact and compensation area, showing a need to include more deadwood types, e.g., late decomposition deadwood, in the translocation scheme. To guide future compensation efforts, the cost for translocation at different spatial scales was calculated. We conclude that translocation of deadwood could provide a cost-efficient new tool for ecological compensation/restoration but that the method needs refinement

Simulating long-term effects of bioenergy extraction on dead wood availability at a landscape scale in Sweden

Wood bioenergy may decrease the reliance on fossil carbon and mitigate anticipated increases in temperature. However, increased use of wood bioenergy may have large impacts on forest biodiversity primarily through the loss of dead wood habitats. We evaluated both the large-scale and long-term effects of different bioenergy extraction scenarios on the availability of dead wood and the suitability of the resulting habitat for saproxylic species, using a spatially explicit forest landscape simulation framework applied in the Swedish boreal forest. We demonstrate that bioenergy extraction scenarios, differing in the level of removal of biomass, can have significant effects on dead wood volumes. Although all of the scenarios led to decreasing levels of dead wood, the scenario aimed at species conservation led to highest volumes of dead wood (about 10 m3 ha-1) and highest connectivity of dead wood patches (mean proximity index of 78), whilst the scenario aimed at reaching zero fossil fuel targets led to the lowest levels (about 8 m3 ha-1) and least connectivity (mean proximity index of 7). Our simulations stress that further exploitation of dead wood from sites where volumes are already below suggested habitat thresholds for saproxylic species will very likely have further negative effects on dead wood dependent species.</p