Lena Gustafsson

Higher levels of multiple ecosystem services are found in forests with more tree species

Forests are of major importance to human society, contributing several crucial ecosystem services. Biodiversity is suggested to positively influence multiple services but evidence from natural systems at scales relevant to management is scarce. Here, across a scale of 400,000 km2, we report that tree species richness in production forests shows positive to positively hump-shaped relationships with multiple ecosystem services. These include production of tree biomass, soil carbon storage, berry production and game production potential. For example, biomass production was approximately 50% greater with five than with one tree species. In addition, we show positive relationships between tree species richness and proxies for other biodiversity components. Importantly, no single tree species was able to promote all services, and some services were negatively correlated to each other. Management of production forests will therefore benefit from considering multiple tree species to sustain the full range of benefits that the society obtains from forests.

Retention Forestry to Maintain Multifunctional Forests: A World Perspective

The majority of the worlds forests are used for multiple purposes, which often include the potentially conflicting goals of timber production and biodiversity conservation. A scientifically validated management approach that can reduce such conflicts is retention forestry, an approach modeled on natural processes, which emerged in the last 25 years as an alternative to clearcutting. A portion of the original stand is left unlogged to maintain the continuity of structural and compositional diversity. We detail retention forestrys ecological role, review its current practices, and summarize the large research base on the subject. Retention forestry is applicable to all forest biomes, complements conservation in reserves, and represents bottom-up conservation through forest manager involvement. A research challenge is to identify thresholds for retention amounts to achieve desired outcomes. We define key issues for future development and link retention forestry with land-zoning allocation at various scales, expanding its uses to forest restoration and the management of uneven—age forests.

Tree retention as a conservation measure in clear-cut forests of northern Europe: a review of ecological consequences

Abstract Since the mid-1990s, it has been common practice to leave trees for biodiversity purposes when clear-cutting in Finland, Norway and Sweden, and regulations for such tree retention are today included in national legislation and certification standards. Peer-reviewed research publications on tree retention from studies performed in the three countries were analyzed and about 50 relevant biodiversity studies were found, with the first published in 1994. Most studies were directed towards beetles and dead wood, especially high stumps. General conclusions were that retention trees (1) provide some of the substrate types required by early-successional species, (2) alleviate the most serious consequences of clear-cutting on biota, and (3) cannot maintain characteristics of intact mature forests. Larger volumes and more trees tend to maintain diversity better. There is a particular lack of studies on dispersal, landscape effects and long-term dynamics. There is a need to study further the relationship between the biota and the amount of trees, as well as their spatial arrangement. Retention trees should preferably be evaluated in relation to other components in multiscaled conservation, including woodland key habitats and larger protected areas.

Can retention forestry help conserve biodiversity? A meta-analysis

Industrial forestry typically leads to a simplified forest structure and altered species composition. Retention of trees at harvest was introduced about 25 years ago to mitigate negative impacts on biodiversity, mainly from clearcutting, and is now widely practiced in boreal and temperate regions. Despite numerous studies on response of flora and fauna to retention, no comprehensive review has summarized its effects on biodiversity in comparison to clearcuts as well as un-harvested forests. Using a systematic review protocol, we completed a meta-analysis of 78 studies including 944 comparisons of biodiversity between retention cuts and either clearcuts or un-harvested forests, with the main objective of assessing whether retention forestry helps, at least in the short term, to moderate the negative effects of clearcutting on flora and fauna. Retention cuts supported higher richness and a greater abundance of forest species than clearcuts as well as higher richness and abundance of open-habitat species than un-harvested forests. For all species taken together (i.e. forest species, open-habitat species, generalist species and unclassified species), richness was higher in retention cuts than in clearcuts. Retention cuts had negative impacts on some species compared to un-harvested forest, indicating that certain forest-interior species may not survive in retention cuts. Similarly, retention cuts were less suitable for some open-habitat species compared with clearcuts. Positive effects of retention cuts on richness of forest species increased with proportion of retained trees and time since harvest, but there were not enough data to analyse possible threshold effects, that is, levels at which effects on biodiversity diminish. Spatial arrangement of the trees (aggregated vs. dispersed) had no effect on either forest species or open-habitat species, although limited data may have hindered our capacity to identify responses. Results for different comparisons were largely consistent among taxonomic groups for forest and open-habitat species, respectively. Synthesis and applications. Our meta-analysis provides support for wider use of retention forestry since it moderates negative harvesting impacts on biodiversity. Hence, it is a promising approach for integrating biodiversity conservation and production forestry, although identifying optimal solutions between these two goals may need further attention. Nevertheless, retention forestry will not substitute for conservation actions targeting certain highly specialized species associated with forest-interior or open-habitat conditions. Our meta-analysis provides support for wider use of retention forestry since it moderates negative harvesting impacts on biodiversity. Hence, it is a promising approach for integrating biodiversity conservation and production forestry, although identifying optimal solutions between these two goals may need further attention. Nevertheless, retention forestry will not substitute for conservation actions targeting certain highly specialized species associated with forest-interior or open-habitat conditions.

Bryophyte flora and vegetation of managed and virgin coniferous forests in South-West Sweden

Abstract One virgin and three managed Picea abies stands in SW Sweden were investigated and their bryophyte flora and vegetation compared. The composition of the bryophyte vegetation did not differ much between the stands. Cover of the single dominant species was very similar. Most common species were Pleurozium schreberi, Dicranum majus, D. polysetum, Sphagnum girgensohni and Hylocomium splendens . Species number and total cover was somewhat higher in the virgin stand (88 species, 73% total cover) than in the managed stands (56–72 species, 49–59% total cover). The diversity (Shannon-Wiener) ranged from 2·3 to 2·9. The importance-value curve for all stands taken together was intermediate between lognormal and geometric in shape. Rare hepatics growing on large logs, such as Calypogeia suecica, Odontoschisma denudatum and Scapania umbrosa , distinguished the virgin stand from the managed stands. Such uncommon log-species are threatened if intense, full-scale forestry continues. Large coniferous forests should be protected if they are to survive. Consideration should be given to the bryophytes when forestry is conducted; large logs should be allowed in a stand, forest fens should be left undrained, and areas with old trees left when clearcutting.

Factors of Importance to Some Lichen Species of Deciduous Broad-Leaved Woods in Southern Sweden

Morphological, anatomical, chemical and ecological evidence show that the South African lichen Roccellina capensis (Nyl. ex Stizenb.) Tehler has developed a dispersal strategy with either sexually dispersed individuals, or vegetatively dispersed, sorediate individuals, hence a putative species-pair. The concept ‘species-pair’ is well-known and widely used in lichenology. It refers to closely related, morphologically indistinguishable lichens that differ from each other by their dispersal strategies only. The so-called ‘ primary species ’ produces fruiting bodies and sexual spores, while its counterpart, the ‘ secondary species ’ is vegetatively dispersed by soredia, isidia or fragmentation. Our study uses molecular information to investigate if R. capensis should be treated as a species-pair or not. The internal transcribed spacer (ITS) of the nuclear ribosomal DNA was sequenced for 17 specimens of R. capensis in order to test if sexual and asexual (sorediate) specimens would group into two distinct, monophyletic groups. Such grouping would support their recognition as separate taxa in a species-pair. We also investigated whether the randomly amplified polymorphic DNA (RAPD) method would be a suitable procedure in population studies of lichens. The analysis of the ITS region produced a single most parsimonious tree. The sexual and asexual specimens were grouped according to their geographical distribution, rather than according to their dispersal strategy. This result clearly shows that the sexual and asexual specimens of R. capensis do not represent a species-pair. The RAPD data set produced an almost completely unresolved tree due to several homoplasious characters, possibly a result of algal contamination.

Woodland key habitats in northern Europe: concepts, inventory and protection.

Abstract The woodland key habitat (WKH) concept has become an essential instrument in biodiversity-orientated forest management in northern Europe. The philosophy behind the concept is basically the same in all of the countries: to conserve the biodiversity of production landscapes by preserving small habitat patches that are supposed to be particularly valuable. This article reviews the definitions, inventories and implementation processes of WKHs in Sweden, Finland, Norway, Latvia, Estonia and Lithuania. Sweden and the Baltic countries have similar WKH models, while the models in Finland and Norway are clearly deviating. Depending on the country, the definitions emphasize different factors, such as soil and bedrock properties, stand structure and occurrence of indicator species. The mean size of the WKHs varies considerably, from 0.7 ha (Finland) to 4.6 ha (Sweden). The degree of formal protection also differs. Preservation of WKHs is primarily based on forest legislation in Finland, Estonia and Latvia, and on forest certification in the other countries. The implementation of the WKH concept is inconsistent between the countries, resulting in different sets of habitats being included in the WKH networks. This makes direct comparisons between the countries difficult, and may hamper the generalization of research results into other areas.

Effects of forest-fuel harvesting on the amount of deadwood on clear-cuts

Forest residue left after clear-cutting is increasingly being used as biofuel in Sweden. Deadwood is an important habitat for many species and a crucial resource for forest biodiversity. On eight clear-cuts in eastern central Sweden, the amount of Picea abies (L.) Karst. deadwood left on the ground was compared with the amount collected in piles for fuelwood extraction. It was found that 65% of the volume, 77% of the surface area and 84% of the pieces of slash were to be extracted. In another study on 23 clear-cuts in the same region, it was found that 36% of the logs left outside piles after clear-cutting were later removed. These studies indicate that a considerable amount of potential substrate is lost during slash extraction.

High occurrence of red-listed bryophytes and lichens in mature managed forests in boreal Sweden

Abstract Successful biodiversity conservation needs to be based on reliable data regarding the distribution and abundance of species. Red Lists summarize the status of rare and declining species. Here we present the first detailed survey (10 m × 10 m resolution) of nationally red-listed bryophytes and lichens at stand level in boreal forests. 30 managed forest production stands in boreal Sweden, soon to be harvested, were surveyed in detail regarding red-listed bryophytes and lichens. On the 180 ha totally investigated, 33 red-listed species were found, representing 35% of all forest red-listed bryophytes and lichens so far recorded from this part of Sweden. The mean number of red-listed species per stand was 10 and varied between 5 and 16. Excluding three species which were so common that, given the time-limit, it was not possible to record all of their occurrences, there were on average 6 number of observations ha−1. The presence and density exceed those earlier found in ‘key habitats’, defined as hot-spots for red-listed species. Almost all observations were made on trees, with 48% on living trees and 52% on dead. Altitude, area and stem volume explained 67% of the red-list species density. The results highlight the importance of unprotected areas for rare and declining species and point to a hitherto unacknowledged high biodiversity value of mature managed boreal forest stands, shaped by a less intense forestry than todays. It also raises questions regarding the use of red-listed species to identify areas of importance to biodiversity. Objective and systematic surveys of red-listed species in the forest landscape, including younger stands, are urgent. Der erfolgreiche Schutz der Biodiversitat muss auf verlasslichen Daten uber die Verbreitung und Abundanz der Arten basieren. Rote Listen fassen den Status seltener und abnehmender Arten zusammen. Hier prasentieren wir die erste detaillierte Erfassung (10 m × 10 m Auflosung) von Bryophyten und Flechten der nationalen Rote Liste auf Bestandsniveau in borealen Waldern. Im borealen Schweden wurden in 30 bewirtschafteten Produktionswalder, die bald geerntet werden sollen, die Bryophyten und Flechten der Roten Liste im Detail erfasst. Auf den insgesamt untersuchten 180 ha wurden 33 Arten der Roten Liste gefunden, die 35% aller Wald-Bryophyten und-Flechten der Roten Liste reprasentieren, die bisher in diesem Teil Schwedens erfasst wurden. Die mittlere Anzahl der Rote-Liste-Arten pro Bestand war 10 und variierte zwischen 5 und 16. Unter Ausschluss von drei Arten, die so gewohnlich waren, dass es bei dem gegebenen Zeitlimit nicht moglich war alle ihre Vorkommen zu erfassen, gab es im Durchschnitt 6 Beobachtungen ha−1. Vorkommen und Dichten ubertrafen die fruher in “Schlusselhabitaten” gefundenen, die als ‘hot spots’ bezeichnet werden. Fast alle Beobachtungen wurden auf Baumen gemacht, mit 48% auf lebenden und 52% auf toten Baumen. Die Hohe, das Gebiet und das Stammvolumen erklarten 67% der Dichte der Rote-Liste-Arten. Die Ergebnisse heben die Wichtigkeit nicht-geschutzter Gebiete fur seltene und abnehmende Arten hervor und weisen auf einen bisher nicht wahrgenommenen hohen Biodiversitatswert von alten bewirtschafteten borealen Waldbestanden hin, die von einer weniger intensiven Forstwirtschaft als der heutigen geformt wurden. Es stellen sich ebenso Fragen, die die Verwendung der Rote-Liste-Arten betreffen, um fur die Biodiversitat wichtige Gebiete zu identifizieren. Objektive und systematische Erfassungen der Rote-Liste-Arten in Waldlandschaften inklusive der jungeren Bestande sind dringend.

Biodiversity and ecosystem services in forest ecosystems: a research agenda for applied forest ecology

Summary Given the substantial contributions of forest biodiversity and ecosystem services to society, forest sciences have a large potential to contribute to the integrity and sustainability of our future. This is especially true when the roles of biodiversity for sustaining ecosystem services are considered. The rapid expansion of sustainable forest management (SFM) has resulted in the adoption of various forest management frameworks intended to safeguard biodiversity. Concurrently, the importance of forest ecosystem services has been increasingly recognized. Although some initiatives aimed at conserving both biodiversity and ecosystem services are emerging, knowledge gaps still exist about their relationships and potential trade-offs in forests. Given recent advancements, increasing opportunities and some lags in forest ecology, further research on biodiversity, ecosystem functions and services will play substantial roles in the development of SFM practices. Here, we identified key issues including (i) relationships between biodiversity and ecosystem function as a foundation of ecological integrity, (ii) resilience thinking to better prepare for and adapt to environmental changes, (iii) social–ecological perspectives that facilitate real-world conservation and management and (iv) theory-driven restoration that bridges science and practice. Thus, we illustrate priorities and future possibilities in applied ecology studies in forests, which will help society and ecosystems to build capacity and resilience to face uncertainty in the changing environment. Synthesis and applications. Under substantial human influences, forests are highly likely to be largely altered, potentially leading to the emergence of novel ecosystems or alternative stable states. Management thus needs more flexible, novel measures to address the significant uncertainty this generates. Resilience-based approaches are important to respond adaptively to future changes and cope with surprises, potentially providing multiple options. Although challenges exist, theory should play an important role in managing, conserving and restoring forest ecosystems. The issues discussed here should receive further attention in the context of the multiple goals of sustainable forest management.