| 1. |
- Eggers, Sönke, et al.
(författare)
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Ecological restoration in boreal forest modifies the structure of bird assemblages
- 2017
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Ingår i: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 401, s. 75-88
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Tidskriftsartikel (refereegranskat)abstract
- Ecological restoration is increasingly recognised as a useful tool for biodiversity conservation in boreal forests. Most restoration methods in this environment aim to emulate natural disturbances, and thereby promote the development of key ecological structures. However, research about forest ecosystem restoration is still in its infancy and the responses of many boreal species groups remain to be described. We established a large-scale field experiment to evaluate the short-term effects of two restoration treatments - prescribed burning and gap cutting involving the creation of dead wood - on breeding bird assemblages in boreal Sweden. We censused breeding birds using territory mapping during two years in forest stands subjected to the two restoration treatments, in untreated controls and in old-growth references (nature reserves) (n = 10 per treatment). Averaged over the two census years, we found 1145 territories of 36 bird species. Total bird species richness and abundance did not differ among treatments. However, prescribed burning led to clear changes in the structure of the bird assemblages. When dividing species according to four functional categorizations (migration, foraging, nesting and successional stage), we found that the abundance of long-distance migrants, ground breeders, strong cavity excavators and species preferring early-successional habitat was higher in burned stands than in untreated controls and gap-cut stands, as was the species richness of bark feeders and strong cavity excavators. In contrast, abundance of off-ground breeders and species richness of crown feeders were lower following prescribed burning than in the controls. The gap cutting treatment did not have any significant effects on the bird assemblages. Ecological restoration through prescribed burning can be a useful tool for the conservation of boreal forest birds, including the ecologically important strong cavity excavators (i.e. woodpeckers (Picidae)). Forest managers should therefore be encouraged to use prescribed burning as a restoration tool to quickly provide habitat for bird species adapted to natural disturbances in boreal forest. (C) 2017 Elsevier B.V. All rights reserved.
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| 2. |
- Hekkala, Anne-Maarit, et al.
(författare)
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Ecological restoration for biodiversity conservation triggers response of bark beetle pests and their natural predators
- 2020
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Ingår i: Forestry: An International Journal of Forest Research. - : Oxford University Press (OUP). - 1464-3626 .- 0015-752X. ; 94, s. 115-126
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Tidskriftsartikel (refereegranskat)abstract
- The restoration of forest structure and function is increasingly being used in boreal forests in order to halt the loss of biodiversity. Often ecological restoration is aimed at increasing the volume of dead and dying trees to enhance the biodiversity of deadwood-dependent organisms, but it may also increase population sizes of pest bark beetle species, even several years following restoration. Herein, we used a large-scale restoration experiment in Northern Sweden to assess the 5 years post-restoration effects of restorative gap cutting and prescribed burning on the populations of a set of economically harmful pest bark beetles (Ips typographus, Polygraphus poligraphus, Tomicus piniperda and Pityogenes chalcographus) and the most important predators of bark beetles, Thanasimus spp. In addition, we assessed the effects of forest stand characteristics at stand and landscape scale on the abundance of I. typographus. Five years post-restoration, gap-cut stands supported the highest abundances of P. poligraphus and contained the highest count of spruce trees newly attacked by bark beetles. By contrast, prescribed burning generally sustained the lowest abundances of pest bark beetles, especially I. typographus and P. poligraphus, and the highest abundance of their natural predators Thanasimus spp. The population abundance of I. typographus was also positively affected by the area of clear cuts within a 500 m radius from the stand. In conclusion, prescribed burning appears to be a safer method for ecological restoration than gap cutting in the long-term. According to our results, a risk of a local bark beetle outbreak still remains 5 years following the initiation of ecological restoration treatments on spruce-dominated mature gap-cut stands.
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| 3. |
- Versluijs, Martijn, et al.
(författare)
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Comparing the effects of even-aged thinning and selective felling on boreal forest birds
- 2020
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Ingår i: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 475
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Tidskriftsartikel (refereegranskat)abstract
- Biodiversity is in decline and therefore alternative forest management approaches have gained interest. One of such approaches is uneven-aged silviculture, which has been suggested to better maintain mature or late-successional forest characteristics and species assemblages than even-aged silviculture. Therefore, it is assumed that uneven-aged silviculture can be a useful tool for landscape planning to benefit biodiversity. Nevertheless, there is a lack of empirical studies regarding bird responses to uneven-aged silviculture in north European boreal ecosystems. Here we test the similarity of bird assemblage structure between mature forests within even-aged silviculture (‘thinning’) and uneven-aged silviculture (‘selective felling’). In spring 2018 we censused breeding birds using territory mapping in 14 thinned stands and 14 selectively felled stands. We found higher abundance and different bird assemblages in thinned stands compared to selectively felled stands. The pied flycatcher, tree pipit and great tit contributed most to the variation of bird assemblages between the two management types. None of the species were more abundant in selectively felled than in thinned stands. According to functional guilds, the abundance of ground breeders, ground feeders and generalists was higher in thinned stands than in selectively felled stands, similar results were found in the species richness of long-distance migrants, ground nesters, secondary cavity nesters and generalists. Independent of management type, time since treatment had an overall effect on assemblage structures, the mistle thrush and wren were negatively correlated with time since treatment, while the chiffchaff showed the opposite trend. Our results suggest that at these locations and given this particular type of uneven-age management, selective felling is less suitable for some abundant generalists than even-aged forest stands reaching the thinning age. However, the results from this study does not provide clear management recommendations aiming to maintain biodiversity, as management guidelines should be based on red-listed species and not on common generalists. Nevertheless, our results stresses the urgent need for more long-term studies comparing the effect of these different silvicultural strategies on bird assemblages. © 2020 The Author(s)
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| 4. |
- Versluijs, Martijn, et al.
(författare)
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Ecological restoration for biodiversity conservation improves habitat quality for an insectivorous passerine in boreal forest
- 2019
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Ingår i: Biological Conservation. - : Elsevier BV. - 0006-3207 .- 1873-2917. ; 237, s. 90-96
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Tidskriftsartikel (refereegranskat)abstract
- It is increasingly recognized that successful biodiversity conservation will necessitate active ecological restoration measures. In boreal forests, emulating natural disturbances is commonly used as a restoration tool for improving habitat quality for a range of sensitive species. We assessed the consequences of prescribed burning and artificial gap creation on the demographic parameters of an insectivorous bird, the pied flycatcher (Ficedula hypoleuca). This to improve our ability to develop strategies for successful ecological restoration aiming at improving the conservation status of boreal forest birds. Pied flycatchers reproduced equally well in nature reserves, forests subjected to ecological restoration and untreated control stands. Nestling body weight was found to be higher in stands restored through prescribed burning. Considering that nestling condition at the time of fledging is known to be positively related to survival rates after fledging, our results suggest a positive effect of prescribed burning on population dynamics and on local habitat quality. Our findings should encourage forest managers to actively use prescribed burning as a management tool in boreal forests to complement other conservation measures. However, one should be careful with generalizing these results to other bird species as they only are directly applicable to pied flycatchers. Still, they may potentially apply also to other insectivorous bird species with similar habitat requirements. In addition, it should be stressed that to maintain diverse boreal forest bird assemblages, heterogeneous landscapes are needed including both burned and unburned forest of different successional stages.
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| 5. |
- Versluijs, Martijn, et al.
(författare)
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Ecological restoration modifies the value of biodiversity indicators in resident boreal forest birds
- 2019
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Ingår i: Ecological Indicators. - : Elsevier BV. - 1470-160X .- 1872-7034. ; 98, s. 104-111
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Tidskriftsartikel (refereegranskat)abstract
- A wide range of different biodiversity indicators have been identified in different biomes and types of environments. However, we currently lack a clear understanding under which circumstances proposed biodiversity indicators are valid indicators and when they are not. Here we conducted a large-scale restoration experiment by emulating natural disturbances through prescribed burning and gap-cutting. From this experiment data of resident forest birds was used to, (1) identify biodiversity indicators in the middle and northern boreal zone, (2) test the effect of forest restoration practices on biodiversity indicators and (3) explore the patterns when biodiversity indicator analyses are performed across a wider range of forest types including both restored and unrestored sites. Additionally, to understand the occurrence of species we correlated their occurrence with local habitat structures across different forest types. We found that both the three-toed woodpecker (Picoides tri-dactylus) and Siberian jay (Perisoreus infaustus) were important biodiversity indicators for the middle/northern boreal zone. The occurrence of these species can generally be used to identify species rich areas across different forest types. However, the three-toed woodpecker, the best indicator for unrestored forest, lost its indicator value after prescribed burning; in these stands the goldcrest (Regulus regulus) was the best biodiversity indicator. Based on habitat associations, we suggest that biodiversity indicators in boreal forest not only indicate high species richness but also structural habitat complexity. Our results draw attention to the fact that one must be careful about using previously identified biodiversity indicators in ecosystems subjected to ecological restoration.
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| 6. |
- Versluijs, Martijn, et al.
(författare)
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Foraging behavior of the Eurasian three-toed woodpecker (Picoides tridactylus) and its implications for ecological restoration and sustainable boreal forest management
- 2020
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Ingår i: Avian Conservation and Ecology. - 1712-6568 .- 1712-6576. ; 15
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Tidskriftsartikel (refereegranskat)abstract
- Several studies have shown that the Three-toed Woodpecker (Picoides tridactylus) is strongly favored by large-scale disturbances, including forest fires. However, natural disturbances have largely disappeared from European boreal forests because of modern forestry practices and fire suppression. We currently lack knowledge on the foraging activity and resource use of the Eurasian Three-toed Woodpecker, especially in burned forests, and this restricts our ability to develop strategies for sustainable forest management and ecological restoration aiming at improving the situation of this woodpecker and associated species. In order to fill this knowledge gap, we studied the characteristics of selected foraging substrates and the foraging behavior of the Three-toed Woodpecker during the breeding season in unburned forests and forests that have been subjected to prescribed burning. We used instantaneous sampling during two consecutive springs (2016-2017), where we observed the woodpeckers' foraging behavior during a total of 977 minutes in burned forest and 962 minutes in unburned forests. The preferred foraging substrate for Three-toed Woodpeckers in both burned and unburned forests can be characterized as freshly dead trees with a DBH > 15 cm. However, data on time spent foraging on different substrates suggest that also substrates in the 5-15 DBH range and living trees are important. Additionally, prescribed burnings led to less pronounced selection of tree species, which suggest that fire may reduce differences in abundance of saproxylic insect prey between tree species. This information on substrate selection and foraging time provide complementary knowledge and thus should be used simultaneously when management strategies for improved woodpecker habitat are developed. Our results suggest that both prescribed burning and protecting forests with high density and diversity of dead wood provides habitat opportunities for Three-toed Woodpeckers and using both in management may maximize conservation outcome.
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| 7. |
- Versluijs, Martijn, et al.
(författare)
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Foraging behaviour of the Eurasian Three-toed Woodpecker Picoides tridactylus in its peak abundance after wildfire
- 2022
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Ingår i: Ardea -Wageningen-. - : Netherlands Ornithologists' Union. - 0373-2266. ; 110, s. 75-88
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Tidskriftsartikel (refereegranskat)abstract
- In the boreal biome, forest fires are the most important natural disturbance influencing tree substrate availability and quality for a range of specialized species. This includes the Eurasian Three-toed Woodpecker Picoides tridactylus, which is known to promptly utilize burned forest habitats. However, there are no studies addressing the foraging behaviour of this woodpecker in forests affected by wildfire. Such knowledge could assist the development of efficient post-fire management strategies which are in line with biodiversity conservation objectives. This study describes the foraging behaviour of the Eurasian Three-toed Woodpecker during the breeding season in a forest area of 13,100 ha in south-central Sweden affected by a major wildfire in 2014. During the second breeding season after fire, we used instantaneous sampling where we observed the foraging behaviour of 28 individuals during a total of 1681 observation minutes. Our results suggest that Norway Spruce Picea abies and larger diameter trees (DBH > 25 cm) are important foraging substrates. However, data on time spent foraging on the different substrates suggest that Scots Pines Pinus sylvestris also are important. In particular, we identified the importance of the root collars, where excavation into sapwood was the main foraging method. Our study was performed during a clearly visible peak of Eurasian Three-toed Woodpecker abundance and this may suggest that the level of food resources available was very high which led to observed foraging patterns not necessarily observed in other types of habitats.
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