The Potential for Long-Term Sustainability in Seminatural Forestry: A Broad Perspective Based on Woodpecker Populations

A Validation Procedure for Ecological Corridor Locations

Connectivity conservation analysis is based on a wide range of approaches designed to pinpoint key ecological corridors in order to maintain multispecies flows. However, the lack of validation procedures with accessible data prevents one from evaluating the accuracy of ecological corridor locations. We propose a new validation procedure to evaluate the accuracy of ecological corridor locations in landscape connectivity approaches. The ability of the procedure to properly rank the accuracy of different landscape connectivity approaches was illustrated in a study case. Maxent model and circuit theory were used to locate ecological corridors for forest bird species, following three approaches based on land cover, umbrella species and multispecies presence data. The validation procedure was used to compare the three approaches. Our validation procedure ranked the three approaches as expected, considering that accuracy in locating ecological corridors is related to the biological realism of calibration data. The corridors modelled were more accurate with species presence data (umbrella and multispecies approaches) compared to land cover proxy (habitat-based approach). These results confirm the quality of the validation procedure. Our validation procedure can be used to: (1) evaluate the accuracy of the location of ecological corridors; (2) select the best approach to locate ecological corridors, and (3) validate the underlying assumptions of landscape connectivity approaches (e.g., dispersal and matrix resistance values).

What does FSC forest certification contribute to biodiversity conservation in relation to national legislation?

Forest certification has emerged as a voluntary, market-driven tool for sustainable forest management (SFM). Its legitimacy depends on its ability to achieve its objectives and to retain the support of stakeholders such as NGOs and the companies that adopt it. This study presents a novel approach for assessing the contributions of forest certification to biodiversity conservation, based on Forest Stewardship Council (FSC) certification in four northern European countries (Finland, Sweden, Estonia, Latvia). In each case, national FSC certification requirements related to specific biodiversity targets were compared with requirements in national legislation. Nearly 80% of the assessed certification requirements were more prescriptive than the national legislation. One-third of these requirements (3-8 per country) were assessed to have a positive contribution to biodiversity conservation, whereas four requirements (up to 2 per country) were assessed to have a low positive contribution. FSC requirements to protect Woodland Key Habitats were identified as having a positive contribution in all four countries, whereas requirements regarding live tree retention in harvests and preserving dead wood had a positive contribution in three countries each. Despite often prescribing similar measures, the other requirements with positive contributions varied between countries depending on the national legislative baseline. The remaining requirements could not be assessed through expert evaluation, indicating the need for additional empirical research to evaluate how the normative requirements translate to impacts in the field, and how the national context may affect their implementation. The approach is globally applicable, repeatable, and provides a basis for designing systematic empirical assessments of the certification impact.

Polypore fungi as a flagship group to indicate changes in biodiversity - a test case from Estonia

Polyporous fungi, a morphologically delineated group of Agaricomycetes (Basidiomycota), are considered well studied in Europe and used as model group in ecological studies and for conservation. Such broad interest, including widespread sampling and DNA based taxonomic revisions, is rapidly transforming our basic understanding of polypore diversity and natural history. We integrated over 40,000 historical and modern records of polypores in Estonia (hemiboreal Europe), revealing 227 species, and including Polyporus submelanopus and P. ulleungus as novelties for Europe. Taxonomic and conservation problems were distinguished for 13 unresolved subgroups. The estimated species pool exceeds 260 species in Estonia, including at least 20 likely undescribed species (here documented as distinct DNA lineages related to accepted species in, e.g., Ceriporia, Coltricia, Physisporinus, Sidera and Sistotrema). Four broad ecological patterns are described: (1) polypore assemblage organization in natural forests follows major soil and tree-composition gradients; (2) landscape-scale polypore diversity homogenizes due to draining of peatland forests and reduction of nemoral broad-leaved trees (wooded meadows and parks buffer the latter); (3) species having parasitic or brown-rot life-strategies are more substrate-specific; and (4) assemblage differences among woody substrates reveal habitat management priorities. Our update reveals extensive overlap of polypore biota throughout North Europe. We estimate that in Estonia, the biota experienced ca. 3-5% species turnover during the twentieth century, but exotic species remain rare and have not attained key functions in natural ecosystems. We encourage new regional syntheses on long studied fungal groups to obtain landscape-scale understanding of species pools, and for elaborating fungal indicators for biodiversity assessments.

Stand Structural Characteristics Are the Most Practical Biodiversity Indicators for Forest Management Planning in Europe

Including biodiversity assessments in forest management planning is becoming increasingly important due to the importance of biodiversity for forest ecosystem resilience provision and sustainable functioning. Here we investigated the potential to include biodiversity indicators into forest management planning in Europe. In particular, we aimed to (i) identify biodiversity indicators and data collection methods for biodiversity assessments at the stand and landscape levels, and (ii) evaluate the practicality of those indicators for forest management planning. We performed a literature review in which we screened 188 research studies published between 1990 and 2020. We selected 94 studies that fulfilled the inclusion criteria and examined in more detail. We considered three aspects of biodiversity: structure, composition, and function, and four forest management categories: unmanaged, managed, plantation, and silvopastoral. We used three criteria to evaluate the practicality of forest biodiversity indicators: cost-effectiveness, ease of application, and time-effectiveness. We identified differences in the practicality of biodiversity indicators for their incorporation into management plans. Stand-level indicators are more practical than landscape-level indicators. Moreover, structural biodiversity indicators (e.g., large trees, canopy openness, and old forest stands) are more useful in management plans than compositional indicators, as these are easily observable by non-professionals and can be obtained by forest inventories. Compositional indicators such are vascular plants, fungi, bryophyte, lichens, and invertebrate species are hard to identify by non-professionals and thus are impractical. Functional indicators (e.g., nutrient cycling) are not sufficiently addressed in the literature. Using recently updated existing databases (e.g., national forest inventories and bird atlases) is very time and cost-efficient. Remote sensing and other technology (e.g., smartphone applications) are promising for efficient data collection in the future. However, more research is needed to make these tools more accurate and applicable to a variety of ecological conditions and scales. Until then, forest stand structural variables derived from inventories can help improve management plans to prepare European forests towards an uncertain future.

The Potential of Production Forests for Sustaining Lichen Diversity: A Perspective on Sustainable Forest Management

There is a critical gap in our knowledge about sustainable forest management in order to maintain biodiversity with respect to allocating conservation efforts between production forests and set-asides. Field studies on this question are notably scarce on species-rich, poorly detectable taxon groups. On the basis of forest lichen surveys in Estonia, we assessed the following: (i) how much production stands contribute to maintaining the full species pool and (ii) how forest habitat conditions affect this contribution for habitat specialist species. The field material was collected in a “semi-natural forestry” system, which mitigates negative environmental impacts of even-aged forestry and forestry drainage by frequently using natural regeneration, tree retention, and low intensity of thinnings. We performed standard-effort surveys of full assemblages of lichens and allied fungi (such as non-lichenized calicioid and lichenicolous fungi) and measured stand structure in 127 2 ha plots, in mainland Estonia. The plots represented four management stages (old growth, mature preharvest forests, clear-cut sites with retention trees, and clear-cut sites without retention trees). The 369 recorded species represent an estimated 70% of the full species pool studied. Our main finding was that production forests supported over 80% of recorded species, but only one-third appears tolerant of management intensification. The landscape-scale potential of production forests through biodiversity-friendly silviculture is approximately twice as high as the number of tolerant species and, additionally, many very rare species depend on setting aside their scattered localities. The potential is much smaller at the scale of individual stands. The scale effect emerges because multiple stands contribute different sets of sensitive and infrequent species. When the full potential of production forests is realized, the role of reserves is to protect specific old-growth dependent taxa (15% to 20% of the species pool). Our study highlights that production forests form a heterogeneous and dynamic target for addressing the biodiversity conservation principle of sustainable forest management.

Recovery of the Critically Endangered bracket fungus Amylocystis lapponica in the Estonian network of strictly protected forests

In regions where primeval forests have vanished it is unclear whether forest protection can sustain specialized old-forest biota, and over what time scale. We report on population expansion of an old-growth specific fungus of European conservation concern, Amylocystis lapponica, in the forest reserve network of Estonia. This conspicuous species was known for 40 years from only single records in one old-growth forest and was categorized nationally as Critically Endangered. During the last 10 years A. lapponica has expanded over the eastern half of the country, with nine subpopulations, in 12 localities, now known, all in long-protected old-growth forests and several > 50 km apart. In most of the new localities historical absence of the species can be reliably assessed based on earlier surveys. The historical remnant subpopulation has also increased. The population size (c. 100 mature individuals) in Estonia indicates the species should be recategorized nationally as Endangered. This success story suggests that more than 50 years of non-intervention may be needed even in large old-forest reserves for old-growth specialist species to recover.