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Exploring the multiple drivers of alpha and beta-diversity dynamics in Europe’s primary forests: Informing conservation strategies
Abstract
Addressing the scope of biodiversity loss is a societal issue. However, consensus regarding effective management practices to attenuate species extinction is lacking. An assessment of spatial variation in species assemblages (beta-diversity) provides a promising framework for informing forest landscape planning. Within the context of recent European Union biodiversity conservation goals, this research demonstrates an application of beta-diversity theory to understand spatial patterns in the distribution of a suite of environmentally-sensitive taxa within Europe’s remaining best-preserved primary forests. We sampled the local community composition (alpha-diversity) of four taxonomic groups (birds, epiphytic and epixylic lichens, saproxylic beetles, and deadwood-inhabiting fungi) to estimate corresponding levels of beta-diversity, as well as the underlying spatial components of nestedness and turnover. To identify particularly sensitive sites on the landscape that are potentially important for multiple species, we assessed beta-diversity congruence among the taxonomic groups. To elucidate critical abiotic factors and resource attributes underpinning biodiversity patterns, we regressed observed levels of local species richness against selected habitat variables. Results show that levels of beta-diversity were high and predominantly driven by spatial turnover, particularly for dispersal-limited organisms having relationships with deadwood. Beta-diversity was lowest for the avian group, reflecting their mobility. The lichen and fungal groups were correlated in terms of beta-diversity and turnover likely due to similar resource requirements. Variation in deadwood attributes (volume, decay stage) was significantly related to the local species richness of beetle and lichen communities. We identified occurrences of several threatened (red-listed) species that were similarly associated with deadwood substrates. We suggest that the beta-diversity patterns and habitat associations revealed by our analyses provide baseline data for comparison with managed systems. In particular, our findings highlight the importance of dead trees and logs for biodiversity conservation, suggesting a need for management strategies that retain an abundant and diverse supply of deadwood in forested landscapes.
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Snags are an important component of beech forests that promote biodiversity. However, their occurrence is completely marginal in managed stands. Creating snags in these stands would greatly enhance biodiversity. We investigated whether snag dimensions are important for saproxylic beetle richness since they are easily transferable parameters to forest management and assessed the presence of other snag microhabitats affecting beetle communities. Data collection was performed using passive flight traps placed on thirty snags in a recent beech reserve. A total of 6706 adults belonging to 231 saproxylic species (53 Red List species, 23%) were captured. The results showed that the most important snag parameters were the diameter (thickness) and canopy openness of the surrounding stands. The occurrence of F. fomentarius, the volume of snag and decay class 3 were marginally significant in terms of the preference of all saproxylic species. Alpha diversity was reduced by an advanced degree of decay and a surprisingly deep stem cavity. After dividing snag thickness into categories (<35; 35-70; >70 cm DBH), we found that categories with snag diameter greater than 35 cm showed little differences in all saproxylic and Red List species richness and diversity indices and exhibited the highest similarity in beetle communities. Regarding recommendations to forest managers in terms of optimization and simplification of practical procedures, we suggest actively creating high stumps to act as snags greater than 35 cm in DBH diameter to promote biodiversity in beech management stands.
Mountain spruce- and beech-dominated forests (SDPF and BDPF) are of major importance in temperate Europe. However, information on the differences between their historical disturbance regimes, structures, and biodiversity is still incomplete. To address this knowledge gap, we established 118 circular research plots across 18 primary forest stands. We analysed the disturbance history of the last 250 years by dendrochronological methods and calculated disturbance frequency, severity, and timing. We also measured forest structure (DBH, tree density, volume of deadwood, and other parameters). Breeding bird populations were examined by point count method during the spring seasons 2017–2018 (SDPF) and 2019–2020 (BDPF). Using direct ordination analysis, we compared the disturbance history, structure and bird assemblage in both forest types. While no differences were found regarding disturbance regimes between forest types, forest structure and bird assemblages were significantly different. SDPF had a significantly higher density of cavities and higher canopy openness, while higher tree species richness and more intense regeneration was found in BDPF. Bird assemblage showed higher species richness in BDPF, but lower total abundance. Most bird species which occurred in both forest types were more numerous in spruce-dominated forests, but more species occurred exclusively in BDPF. Further, some SDPF- preferring species were found in naturally disturbed patches in BDPF. We conclude that although natural disturbances are important drivers of primary forest structures, differences in the bird assemblages in the explored primary forest types were largely independent of disturbance regimes.
Assessing the impacts of natural disturbance on the functioning of complex forest systems are imperative in the context of global change. The unprecedented rate of contemporary species extirpations, coupled with widely held expectations that future disturbance intensity will increase with warming, highlights a need to better understand how natural processes structure habitat availability in forest ecosystems. Standardised typologies of tree-related microhabitats (TreMs) have been developed to facilitate assessments of resource availability for multiple taxa. However, natural disturbance effects on TreM diversity have never been assessed. We amassed a comprehensive dataset of TreM occurrences and a concomitant 300-year disturbance history reconstruction that spanned large environmental gradients in temperate primary forests. We used nonlinear analyses to quantify relations between past disturbance parameters and contemporary patterns of TreM occurrence. Our results reveal that natural forest dynamics, characterised
Protecting structural features, such as tree‐related microhabitats (TreMs), is a cost‐effective tool crucial for biodiversity conservation applicable to large forested landscapes. Although the development of TreMs is influenced by tree diameter, species, and vitality, the relationships between tree age and TreM profile remain poorly understood. Using a tree‐ring‐based approach and a large data set of 8038 trees, we modeled the effects of tree age, diameter, and site characteristics on TreM richness and occurrence across some of the most intact primary temperate forests in Europe, including mixed beech and spruce forests. We observed an overall increase in TreM richness on old and large trees in both forest types. The occurrence of specific TreM groups was variably related to tree age and diameter, but some TreM groups (e.g., epiphytes) had a stronger positive relationship with tree species and elevation. Although many TreM groups were positively associated with tree age and diameter, only two TreM groups in spruce stands reacted exclusively to tree age (insect galleries and exposed sapwood) without responding to diameter. Thus, the retention of trees for conservation purposes based on tree diameter appears to be a generally feasible approach with a rather low risk of underrepresentation of TreMs. Because greater tree age and diameter positively affected TreM development, placing a greater emphasis on conserving large trees and allowing them to reach older ages, for example, through the establishment of conservation reserves, would better maintain the continuity of TreM resource and associated biodiversity. However, this approach may be difficult due to the widespread intensification of forest management and global climate change.
Background
Gradients in local environmental characteristics may favour the abundance of species with particular traits, while other species decline, or favour species with different traits at the same time, without an increase in average species abundances. Therefore, we asked: do variations in species and traits differ along gradients of deadwood variables? Do species abundance and trait occurrence change with species richness within or between functional groups? Thus, we analysed the beetle assemblages of five forest sites located in Italy, along the Apennines mountains.
Methods
From 2012 to 2018 we sampled beetles and five deadwood types in 193 plots to characterise the deadwood gradient: standing dead trees, snags, dead downed trees, coarse woody debris, and stumps. We modelled beetle species relative abundances and trophic traits occurrences against the deadwood variables using joint species distribution models.
Results
Out of 462 species, only 77 showed significant responses to at least one deadwood type, with a weak mean response across species. Trophic groups showed mostly negative responses to deadwood variables. Species abundance increased with species richness among sites only for phytophagous and saproxylophagous. Similarly, trait occurrence did not increase with species richness among sites, except for phytophagous and saproxylophagous. However, trait occurrence changed significantly with species richness of several trophic groups within some sites. We found that increases in species richness do not result in decreases in species abundance of a given trophic group, but rather null or positive relationships were found suggesting low interspecific competition.
Conclusions
Our findings suggest that in Mediterranean mountain forests there is still room for increasing the level of naturalness, at least for what concerns deadwood management. On one side, our findings suggest that competition for deadwood substrates is still low, on the other side they indicate that increasing deadwood volume and types to improve overall beetle diversity may increase also beetle abundances.
The patterns of successional change of decomposer communities is unique in that resource availability predictably decreases as decomposition proceeds. Saproxylic (i.e. deadwood‐dependent) beetles are a highly diverse and functionally important decomposer group, and their community composition is affected by both deadwood characteristics and other environmental factors. Understanding how communities change with faunal succession through the decomposition process is important as this process influences terrestrial carbon dynamics.
Here, we evaluate how beta‐diversity of saproxylic beetle communities change with succession, as well as the effects of different major drivers of beta‐diversity, such as deadwood tree species, spatial distance between locations, climate and forest structure.
We studied spatial beta‐diversity (i.e. dissimilarity of species composition between deadwood logs in the same year) of saproxylic beetle communities over 8 years of wood decomposition. Our study included 379 experimental deadwood logs comprising 13 different tree species in 30 forest stands in Germany. We hypothesized that the effects of tree species dissimilarity, measured by phylogenetic distance, and climate on beta‐diversity decrease over time, while the effects of spatial distance between logs and forest structure increase.
Observed beta‐diversity of saproxylic beetle communities increased over time, whereas standardized effects sizes (SES; based on null models) of beta‐diversity decreased indicating higher beta‐diversity than expected during early years. Beta‐diversity increased with increasing phylogenetic distance between tree species and spatial distance among regions, and to a lesser extent with spatial distance within regions and differences in climate and forest structure. Whereas effects of space, climate and forest structure were constant over time, the effect of phylogenetic distance decreased.
Our results show that the strength of the different drivers of saproxylic beetle community beta‐diversity changes along deadwood succession. Beta‐diversity of early decay communities was strongly associated with differences among tree species. Although this effect decreased over time, beta‐diversity remained high throughout succession. Possible explanations for this pattern include differences in decomposition rates and fungal communities between logs or the priority effect of early successional communities. Our results suggest that saproxylic beetle diversity can be enhanced by promoting forests with diverse tree communities and structures.
Extremely old trees have important roles in providing insights about historical climatic events and supporting cultural values, yet there has been limited work on their global distribution and conservation. We extracted information on 197,855 tree cores from 4854 sites and combined it with other tree age (e.g., the OLDLIST) data from a further 156 sites to determine the age of the world's oldest trees and quantify the factors influencing their global distribution. We found that extremely old trees >1000 years were rare. Among 30 individual trees that exceeded 2000 years old, 27 occurred in high mountains. We modeled maximum tree age with climatic, soil topographic, and anthropogenic variables, and our regression models demonstrated that elevation, human population density, soil carbon content, and mean annual temperature were key determinants of the distribution of the world's oldest trees. Specifically, our model predicted that many of the oldest trees will occur in high‐elevation, cold, and arid mountains with limited human disturbance. This pattern was markedly different from that of the tallest trees, which were more likely to occur in relatively more mesic and productive locations. Global warming and expansion of human activities may induce rapid population declines of extremely old trees. New strategies, including targeted establishment of conservation reserves in remote regions, especially those in western parts of China and the United States, are required to protect these trees.
How to manage forest for biodiversity conservation is an ongoing debate. We argue that maximizing biodiversity in managed forest landscapes requires a diversity of forest management regimes in space and time. This will generate high levels of habitat heterogeneity at a landscape scale, which in turn will support various groups of forest species. Based on concepts from landscape ecology, we formulate five hypotheses on how management diversity, i.e. combining various management approaches can benefit overall biodiversity across a production forest landscape. First, management diversity will increase habitat diversity and, therefore, beta diversity (the habitat diversity hypothesis). Second, asynchrony in management timing will enhance long-term availability of different habitat types (the spatio-temporal heterogeneity hypothesis). Third, management to create spatial adjacency or proximity of stands with different management or successional stages will increase biodiversity by providing simultaneous access to multiple resources (the interspersion hypothesis). Fourth, heterogeneous unmanaged set-aside forests, interspersed with managed forests, are needed for complete biodiversity conservation (the natural forest hypothesis). Fifth, management diversity will create functional landscape connectivity between protected forests for multiple species through time (the temporary corridor hypothesis). Although strongly grounded in landscape and forest ecology, these five hypotheses remain largely under-investigated, and we suggest methods for how they can be tested. In the meantime, we suggest that increasing forest management diversity represents a risk-spreading approach for adaptation to global change, and therefore is likely a reasonable objective for sustainable forestry moving forward.
Microclimate is a crucial driver of saproxylic beetle assemblages, with more species often found in sunny forests than in shady ones. Whether this pattern is caused by a higher detectability due to increased beetle activity under sunny conditions or a greater diversity of beetles emerging from sun-exposed deadwood remains unclear. This study examined whether sun exposure leads to higher microclimatic heterogeneity in deadwood and whether this drives beetle diversity in deadwood logs and at forest stand scale. Saproxylic beetles were sampled at the stand scale using flight-interception traps and at object scale using stem-emergence traps on deadwood logs at the same site. The variability in wood surface temperature was measured on single logs and between logs as a proxy for microclimatic heterogeneity in deadwood. Abundance in sunny forests was higher at the stand scale, and in shady forests at the object scale. The estimated number of species was higher in sunny forests at both scales and correlated positively with temperature variability on single logs and between logs at the stand scale and, albeit weakly, with temperature variability on single logs at the object scale. Gamma-diversity, and thus beta-diversity, across logs at the object scale was higher in sunny forests. These findings indicate that sun exposure promotes saproxylic beetle diversity due to higher microclimatic heterogeneity within and between deadwood logs. Our study therefore corroborates previous research demonstrating the importance of canopy cover and microclimate for forest biodiversity.
International and national initiatives aim to conserve at least 30% of lands and waters by 2030. To safeguard biodiversity, conservation actions must be distributed in places that represent ecosystem and species diversity. Various methods of prioritizing sites for conservation have been used in local and global assessments. However, the performance and consequences of alternative methods are usually unknown. Such comparisons are needed to confidently implement national and international conservation initiatives. Here, we compared four widely-used methods of prioritizing sites in the contiguous United States for conserving species of mammals, birds, amphibians, and reptiles. Specifically, we calculated and mapped species richness, rarity-weighted richness, and two complementarity-based prioritizations (additive benefit function [ABF] and core area zonation [CAZ] in the software Zonation). We compared maps derived from these alternatives with respect to spatial locations and overlap, patch size distributions of the top-30% priorities, and existing ownership and protected-area status. We used species-accumulation curves across ranked priorities to evaluate performance of methods and compared results at 30% total area. Mapped locations and patch sizes of the highest priorities varied by taxonomic class and method of prioritization. Complementarity-based methods (ABF and CAZ) more efficiently represented species than methods based on richness or rarity-weighted richness, especially for taxa with higher beta diversity (amphibians). ABF and CAZ methods also resulted in greater conservation opportunity for the top 30% of priorities compared to maps of richness. Area-based conservation targets, such as the “30 by 30” initiative, must distribute limited resources in ways that safeguard all species. Our results show that spatial locations and configuration, performance, and conservation opportunity vary among prioritization methods and taxonomic classes.
Aim
Natural disturbances influence forest structure, successional dynamics, and, consequently, the distribution of species through time and space. We quantified the long-term impacts of natural disturbances on lichen species richness and composition in primary mountain forests, with a particular focus on the occurrence of endangered species.
Location
Ten primary mountain spruce forest stands across five mountain chains of the Western Carpathians, a European hotspot of biodiversity.
Methods
Living trees, snags, and downed logs were surveyed for epiphytic and epixylic lichens in 57 plots. Using reconstructed disturbance history, we tested how lichen species richness and composition was affected by the current forest structure and disturbance regimes in the past 250 years. We also examined differences in community composition among discrete microhabitats.
Results
Dead standing trees as biological legacies of natural disturbances promoted lichen species richness and occurrence of threatened species at the plot scale, suggesting improved growing conditions for rare and common lichens during the early stages of recovery post-disturbance. However, high-severity disturbances compromised plot scale species richness. Both species richness and the number of old-growth specialists increased with time since disturbance (i.e. long-term uninterrupted succession). No lichen species was strictly dependent on live trees as a habitat, but numerous species showed specificity to logs, standing objects, or admixture of tree species.
Main conclusions
Lichen species richness was lower in regenerating, young, and uniform plots compared to overmature and recently disturbed areas. Natural forest dynamics and its legacies are critical to the diversity and species composition of lichens. Spatiotemporal consequences of natural dynamics require a sufficient area of protected forests for provisioning continual habitat variability at the landscape scale. Ongoing climatic changes may further accentuate this necessity. Hence, we highlighted the need to protect the last remaining primary forests to ensure the survival of regionally unique species pools of lichens.
Primary forests, defined here as forests where the signs of human impacts, if any, are strongly blurred due to decades without forest management, are scarce in Europe and continue to disappear. Despite these losses, we know little about where these forests occur. Here, we present a comprehensive geodatabase and map of Europe’s known primary forests. Our geodatabase harmonizes 48 different, mostly field-based datasets of primary forests, and contains 18,411 individual patches (41.1 Mha) spread across 33 countries. When available, we provide information on each patch (name, location, naturalness, extent and dominant tree species) and the surrounding landscape (biogeographical regions, protection status, potential natural vegetation, current forest extent). Using Landsat satellite-image time series (1985–2018) we checked each patch for possible disturbance events since primary forests were identified, resulting in 94% of patches free of significant disturbances in the last 30 years. Although knowledge gaps remain, ours is the most comprehensive dataset on primary forests in Europe, and will be useful for ecological studies, and conservation planning to safeguard these unique forests.
Numerous bird species, often rare or endangered, rely on the presence of standing and downed deadwood for shelter, nesting, and foraging. Habitat quality was evaluated on the basis of deadwood volume, the density of large standing deadwood, and the space filling index (SFI). The SFI reflects the degree of space filling of the bottom layers taking into account tree trunks, seedlings, saplings, ground vegetation, stumps, and downed deadwood. Analysis encompassed all special protection areas (SPAs) in Poland (a total of 107 SPAs containing 7974 sample plots monitored under the National Forest Inventory). An additional in-depth analysis was conducted for 30 SPAs with the greatest share of forest habitats. The studied indicators varied substantially both between and within individual SPAs, with deadwood volume ranging from 1.3 to 50.5 m 3 ha −1 (mean of 9.0 m 3 ha −1) and the density of large standing deadwood (diameter at breast height ≥ 30 cm) from 0.1 to 16.0 ind ha −1 (mean of 2.2 ind ha −1). These values were relatively low compared to the density of living trees with corresponding dimensions (111 ind ha −1). SFI analysis indicated high or very high space filling of the bottom forest layers on 14-56% of sample plots in a given SPA. The presence of deadwood was found to be significantly positively affected by SPA location in the mountains, a greater proportion of sites with higher fertility, a greater share of forest area under strict protection, as well as higher stand volume within a given SPA. The correlation between deadwood volume and the density of birds (primary and secondary cavity nesters) in individual SPAs was positive (R = 0.60). As compared to lowland areas, SPAs in mountain areas are generally characterized by high stand volumes, a greater density of large living trees, and a greater amount of diverse deadwood. In those areas conservation measures should involve continuous monitoring and diagnosing of any problems associated with the populations of individual bird species; focused efforts should be implemented to support those species that exhibit unfavorable population trends. In most lowland SPAs measures aimed at the improvement of site conditions for birds must be more extensive than in the mountains, with a low abundance of dead trees (especially large ones). These parameters can be improved by retaining some senescent stands in managed forests until their natural death and implementing a strict protection regime in areas of high conservation value.
The relationships between structural complexity, deadwood abundance, microhabitat type and species-diversity indicators are excellent tools to monitor biodiversity in forest ecosystems.
In spite of their importance, correlations between structural traits and Coleoptera communities in Mediterranean mountain forests have only rarely been investigated. Consequently, the magnitude and direction of the relationships between forest traits and biodiversity indicators remain poorly understood. In this study, we analyzed whether biodiversity indices of saproxylic and non-saproxylic beetle communities could be influenced by stand structure, microhabitat type, and deadwood abundance in two protected beech forests located in the central and southern Apennines (namely Gran Sasso e Monti della Laga National Park, GSML, and Cilento, Vallo di Diano e Alburni National Park, CVDA). Standard measurements of forest structural traits and quantitative assessment of tree microhabitats and deadwood were carried out. Adult beetles were collected using window flight traps and emergence traps on decaying deadwood. The two beech forests were different in terms of both beetle communities and structural traits. A two-block partial least squares analysis 2B-PLS highlighted differences in biodiversity indices and structural traits between the two forest ecosystems. In GSML, we observed that biodiversity indices were positively correlated with the volume of coarse woody debris and the presence fungal infections, clefts into the sapwood, and woodpecker cavities, while more dominant beetle communities were found under denser canopy cover. In CVDA, Coleoptera abundance was positively correlated with the basal area and crown broken microhabitats. Our results point toward the relevance of ecological attributes in tracking changes in beetle biodiversity in specific forest contexts. In these protected Mediterranean mountain beech stands, in which the main forest management strategies have the primary objective of biodiversity conservation, we suggest to progressively increase the structural diversity and canopy dynamics, as well as the volume of coarse woody debris.
Understanding how abiotic disturbance and biotic interactions determine pollinator and flowering‐plant diversity is critically important given global climate change and widespread pollinator declines. To predict responses of pollinators and flowering‐plant communities to changes in wildfire disturbance, a mechanistic understanding of how these two trophic levels respond to wildfire severity is needed.
We compared site‐to‐site variation in community composition (β‐diversity), species richness and abundances of pollinators and flowering plants among landscapes with no recent wildfire (unburned), mixed‐severity wildfire and high‐severity wildfire in three sites across the Northern Rockies Ecoregion, USA. We used variation partitioning to assess the relative contributions of wildfire, other abiotic variables (climate, soils and topography) and biotic associations among plant and pollinator composition to community assembly of both trophic levels.
Wildfire disturbance generally increased species richness and total abundance, but decreased β‐diversity, of both pollinators and flowering plants. However, reductions in β‐diversity from wildfire appeared to result from increased abundances following fires, resulting in higher local species richness of pollinators and flowers in burned than unburned landscapes. After accounting for differences in abundance, standardized effect sizes of β‐diversity were higher in burned than unburned landscapes, suggesting that wildfire enhances non‐random assortment of pollinator and flowering‐plant species among local communities.
Wildfire disturbance mediated the relative importance of mutualistic associations to β‐diversity of pollinators and flowering plants. The influence of pollinator β‐diversity on flowering‐plant β‐diversity increased with wildfire severity, whereas the influence of flowering‐plant β‐diversity on pollinator β‐diversity was greater in mixed‐severity than high‐severity wildfire or unburned landscapes. Moreover, biotic associations among pollinator and plant species explained substantial variation in β‐diversity of both trophic levels beyond what could be explained by wildfire and all other abiotic and spatial factors combined.
Synthesis. Wildfire disturbance and plant–pollinator interactions both strongly influenced the assembly of pollinator and flowering‐plant communities at local and regional scales. However, biotic interactions were generally more important drivers of community assembly in disturbed than undisturbed landscapes. As wildfire regimes continue to change globally, predicting its effects on biodiversity will require a deeper understanding of the ecological processes that mediate biotic interactions among linked trophic levels.
Red-listed species are often used as target species in selection of sites for conservation. However, limitations to their use have been pointed out, and here we address the problem of expected high spatio-temporal dynamics of red-listed species. We used species data (vascular plants, bryophytes, macrolichens and polypore fungi) from two inventories 17 years apart to estimate temporal turnover of red-listed and non-red-listed species in two forest areas (147 and 195 ha) and of plots (0.25 ha) within each area. Furthermore, we investigated how turnover of species affected the rank order of plots regarding richness of red-listed species, using two different national Red List issues (1998 and 2015). In both study areas, temporal turnover was substantial, despite minor changes in the overall number of species. At plot level, temporal turnover in red-listed species was higher than in non-red-listed species, but similar to non-red-listed species of the same frequency of occurrence. Adding the effect of changing identities of species red-listed according to the two Red List issues, further increased the estimated spatio-temporal dynamics. Recorded spatio-temporal turnover also resulted in substantial changes in the rank order of plots regarding richness of red-listed species. Using rare red-listed species for site selection may therefore be accompanied by a higher loss of conservation effectiveness over time than for more common species, and particularly at finer scales.
Although habitat loss is the predominant factor leading to biodiversity loss in the Anthropocene1,2, exactly how this loss manifests—and at which scales—remains a central debate3–6. The ‘passive sampling’ hypothesis suggests that species are lost in proportion to their abundance and distribution in the natural habitat7,8, whereas the ‘ecosystem decay’ hypothesis suggests that ecological processes change in smaller and more-isolated habitats such that more species are lost than would have been expected simply through loss of habitat alone9,10. Generalizable tests of these hypotheses have been limited by heterogeneous sampling designs and a narrow focus on estimates of species richness that are strongly dependent on scale. Here we analyse 123 studies of assemblage-level abundances of focal taxa taken from multiple habitat fragments of varying size to evaluate the influence of passive sampling and ecosystem decay on biodiversity loss. We found overall support for the ecosystem decay hypothesis. Across all studies, ecosystems and taxa, biodiversity estimates from smaller habitat fragments—when controlled for sampling effort—contain fewer individuals, fewer species and less-even communities than expected from a sample of larger fragments. However, the diversity loss due to ecosystem decay in some studies (for example, those in which habitat loss took place more than 100 years ago) was less than expected from the overall pattern, as a result of compositional turnover by species that were not originally present in the intact habitats. We conclude that the incorporation of non-passive effects of habitat loss on biodiversity change will improve biodiversity scenarios under future land use, and planning for habitat protection and restoration.
The evolutionary split between gymnosperms and angiosperms has far‐reaching implications for the current communities colonizing trees. The inherent characteristics of dead wood include its role as a spatially scattered habitat of plant tissue, transient in time. Thus, local assemblages in deadwood forming a food web in a necrobiome should be affected not only by dispersal ability but also by host tree identity, the decay stage and local abiotic conditions. However, experiments simultaneously manipulating these potential community drivers in deadwood are lacking. To disentangle the importance of spatial distance and microclimate, as well as host identity and decay stage as drivers of local assemblages, we conducted two consecutive experiments, a 2‐tree species and 6‐tree species experiment with 80 and 72 tree logs, respectively, located in canopy openings and under closed canopies of a montane and a lowland forest. We sampled saproxylic beetles, spiders, fungi and bacterial assemblages from logs. Variation partitioning for community metrics based on a unified framework of Hill numbers showed consistent results for both studies: host identity was most important for sporocarp‐detected fungal assemblages, decay stage and host tree for DNA‐detected fungal assemblages, microclimate and decay stage for beetles and spiders and decay stage for bacteria. Spatial distance was of minor importance for most taxa but showed the strongest effects for arthropods. The contrasting patterns among the taxa highlight the need for multi‐taxon analyses in identifying the importance of abiotic and biotic drivers of community composition. Moreover, the consistent finding of microclimate as the primary driver for saproxylic beetles compared to host identity shows, for the first time that existing evolutionary host adaptions can be outcompeted by local climate conditions in deadwood.
Estimates of historical disturbance patterns are essential to guide forest management aimed at ensuring the sustainability of ecosystem functions and biodiversity. However, quantitative estimates of various disturbance characteristics required in management applications are rare in longer‐term historical studies. Thus, our objectives were to (1) quantify past disturbance severity, patch size, and stand proportion disturbed and (2) test for temporal and subregional differences in these characteristics. We developed a comprehensive dendrochronological method to evaluate an approximately two‐century‐long disturbance record in the remaining Central and Eastern European primary mountain spruce forests, where wind and bark beetles are the predominant disturbance agents. We used an unprecedented large‐scale nested design data set of 541 plots located within 44 stands and 6 subregions. To quantify individual disturbance events, we used tree‐ring proxies, which were aggregated at plot and stand levels by smoothing and detecting peaks in their distributions. The spatial aggregation of disturbance events was used to estimate patch sizes. Data exhibited continuous gradients from low‐ to high‐severity and small‐ to large‐size disturbance events. In addition to the importance of small disturbance events, moderate‐scale (25–75% of the stand disturbed, >10 ha patch size) and moderate‐severity (25–75% of canopy disturbed) events were also common. Moderate disturbances represented more than 50% of the total disturbed area and their rotation periods ranged from one to several hundred years, which is within the lifespan of local tree species. Disturbance severities differed among subregions, whereas the stand proportion disturbed varied significantly over time. This indicates partially independent variations among disturbance characteristics. Our quantitative estimates of disturbance severity, patch size, stand proportion disturbed, and associated rotation periods provide rigorous baseline data for future ecological research, decisions within biodiversity conservation, and silviculture intended to maintain native biodiversity and ecosystem functions. These results highlight a need for sufficiently large and adequately connected networks of strict reserves, more complex silvicultural treatments that emulate the natural disturbance spectrum in harvest rotation times, sizes, and intensities, and higher levels of tree and structural legacy retention.
The expected future intensification of forest disturbance as a consequence of ongoing anthropogenic climate change highlights the urgent need to more robustly quantify associated biotic responses. Saproxylic beetles are a diverse group of forest invertebrates representing a major component of biodiversity that is associated with the decomposition and cycling of wood nutrients and carbon in forest ecosystems. Disturbance-induced declines or shifts in their diversity indicate the loss of key ecological and/or morphological species traits that could change ecosystem functioning. Functional and phylogenetic diversity of biological communities is commonly used to link species communities to ecosystem functions. However, our knowledge on how disturbance intensity alters functional and phylogenetic diversity of saproxylic beetles is incomplete. Here, we analyzed the main drivers of saproxylic beetle abundance and diversity using a comprehensive dataset from montane primary forests in Europe. We investigated cascading relationships between 250 years of historical disturbance mechanisms, forest structural attributes and the taxonomic, phylogenetic and functional diversity of present-day beetle communities. Our analyses revealed that historical disturbances have significant effects on current beetle communities. Contrary to our expectations, different aspects of beetle communities, that is, abundance, taxonomic, phylogenetic and functional diversity, responded to different disturbance regime components. Past disturbance frequency was the most important component influencing saproxylic beetle communities and habitat via multiple temporal and spatial pathways. The quantity of deadwood and its diameter positively influenced saproxylic beetle abundance and functional diversity, whereas phylogenetic diversity was positively influenced by canopy openness. Analyzing historical disturbances, we observed that current beetle diversity is far from static, such that the importance of various drivers might change during further successional development. Only forest landscapes that are large enough to allow for the full range of temporal and spatial patterns of disturbances and post-disturbance development will enable long-term species coexistence and their associated ecosystem functions.
High numbers of threatened species might be expected to occur where overall species richness is also high; however, this explains only a proportion of the global variation in threatened species richness. Understanding why many areas have more or fewer threatened species than would be expected given their species richness, and whether that is consistent across taxa, is essential for identifying global conservation priorities. Here, we show that, after controlling for species richness, environmental factors, such as temperature and insularity, are typically more important than human impacts for explaining spatial variation in global threatened species richness. Human impacts, nevertheless, have an important role, with relationships varying between vertebrate groups and zoogeographic regions. Understanding this variation provides a framework for establishing global conservation priorities, identifying those regions where species are inherently more vulnerable to the effects of threatening human processes, and forecasting how threatened species might be distributed in a changing world. Understanding to what extent geographic patterns in threatened species diversity are driven by environmental features or human activities could aid conservation. Here, Howard et al. investigate broad scale patterns in species richness of threatened vertebrates and test the role of environmental and anthropogenic drivers.
Forests are under increasing pressure globally and the establishment of protected areas has long been used as a conservation tool to preserve them. Seven categories of protected areas have been defined by the International Union for Conservation of Nature (IUCN) with different management objectives and protection levels. However, recent studies raised questions over whether protected areas are effective in preventing ecosystem degradation and whether IUCN categories vary in their effectiveness. In this study, we analysed forest loss and trends between 2001 and 2014 within IUCN protected areas at a global scale and within sixteen Intergovernmental Platform for Biodiversity and Ecosystem services (IPBES) subregions, relevant for international policy. As habitat protection can be driven by the location of protected areas and as the amount of forest within protected sites is highly unequal, we reported the forest loss integrating the proximity of roads and population, as well as the amount of initial forest in 2000. Our results show that worldwide, the highest protection categories experienced less forest loss than those allowing more human intervention, although this result was reversed in three IPBES subregions. Moreover, in four subregions there was more forest loss within protected areas than outside. We also found accelerating rates of forest loss in protected areas across all IUCN categories, more pronounced in the highest protection IUCN categories. Our results highlight the importance of moving the discussion of the post-2020 biodiversity framework for protected areas beyond simple general areal targets and that areas with poor implementation effectiveness should benefit from additional support.
Reducing the rate of global biodiversity loss is a major challenge facing humanity¹, as the consequences of biological annihilation would be irreversible for humankind2–4. Although the ongoing degradation of ecosystems5,6 and the extinction of species that comprise them7,8 are now well-documented, little is known about the role that remaining wilderness areas have in mitigating the global biodiversity crisis. Here we model the persistence probability of biodiversity, combining habitat condition with spatial variation in species composition, to show that retaining these remaining wilderness areas is essential for the international conservation agenda. Wilderness areas act as a buffer against species loss, as the extinction risk for species within wilderness communities is—on average—less than half that of species in non-wilderness communities. Although all wilderness areas have an intrinsic conservation value9,10, we identify the areas on every continent that make the highest relative contribution to the persistence of biodiversity. Alarmingly, these areas—in which habitat loss would have a more-marked effect on biodiversity—are poorly protected. Given globally high rates of wilderness loss¹⁰, these areas urgently require targeted protection to ensure the long-term persistence of biodiversity, alongside efforts to protect and restore more-degraded environments.
The long-term success of sites selected for species conservation depends on the persistence of target species. Red List species or threatened species lists are frequently defined as target species, but when Red Lists are updated, their species composition may change. Here we investigate the effects of Red List updates on the long-term robustness of fine-scale site selection. We used records of red-listed species (vascular plants, bryophytes, macrolichens, and polypore fungi) recorded in 1997–1998 in 1058 sample plots (50 × 50 m) from six forest landscapes in Norway, and four consecutive issues of the Norwegian Red List for species (1998, 2006, 2010, 2015). Sites were selected based on the first issue (1998) using both a scoring (“hotspot”) approach and a complementarity approach, and the ability of selected sites to include red-listed species of later issues was measured. In four boreal forests the mean proportion of red-listed species included in selected sites were reduced by18% during the study period, whereas no such effect was found in two hemiboreal forests, where increased clustering of red-listed species in sites compensated for target species changes. Changing target species adds to earlier documented challenges caused by population dynamics, and we suggest that alternatives to using occurrences of target species in site selection should be considered, and particularly at finer spatial scales. Keywords: Changing targets, Effectiveness, Red list updates, Site selection, Spatial distribution
The successional dynamics of forests—from canopy openings to regeneration, maturation, and decay—influence the amount and heterogeneity of resources available for forest‐dwelling organisms. Conservation has largely focused only on selected stages of forest succession (e.g., late‐seral stages). However, to develop comprehensive conservation strategies and to understand the impact of forest management on biodiversity, a quantitative understanding of how different trophic groups vary over the course of succession is needed.
We classified mixed mountain forests in Central Europe into nine successional stages using airborne Li DAR . We analysed α‐ and β‐diversity of six trophic groups encompassing approximately 3,000 species from three kingdoms. We quantified the effect of successional stage on the number of species with and without controlling for species abundances and tested whether the data fit the more‐individuals hypothesis or the habitat heterogeneity hypothesis. Furthermore, we analysed the similarity of assemblages along successional development.
The abundance of producers, first‐order consumers, and saprotrophic species showed a U‐shaped response to forest succession. The number of species of producer and consumer groups generally followed this U‐shaped pattern. In contrast to our expectation, the number of saprotrophic species did not change along succession. When we controlled for the effect of abundance, the number of producer and saproxylic beetle species increased linearly with forest succession, whereas the U‐shaped response of the number of consumer species persisted. The analysis of assemblages indicated a large contribution of succession‐mediated β‐diversity to regional γ‐diversity.
Synthesis and applications . Depending on the species group, our data supported both the more‐individuals hypothesis and the habitat heterogeneity hypothesis. Our results highlight the strong influence of forest succession on biodiversity and underline the importance of controlling for successional dynamics when assessing biodiversity change in response to external drivers such as climate change. The successional stages with highest diversity (early and late successional stages) are currently strongly underrepresented in the forests of Central Europe. We thus recommend that conservation strategies aim at a more balanced representation of all successional stages.
Aim
Primary forests have high conservation value but are rare in Europe due to historic land use. Yet many primary forest patches remain unmapped, and it is unclear to what extent they are effectively protected. Our aim was to (1) compile the most comprehensive European‐scale map of currently known primary forests, (2) analyse the spatial determinants characterizing their location and (3) locate areas where so far unmapped primary forests likely occur.
Location
Europe.
Methods
We aggregated data from a literature review, online questionnaires and 32 datasets of primary forests. We used boosted regression trees to explore which biophysical, socio‐economic and forest‐related variables explain the current distribution of primary forests. Finally, we predicted and mapped the relative likelihood of primary forest occurrence at a 1‐km resolution across Europe.
Results
Data on primary forests were frequently incomplete or inconsistent among countries. Known primary forests covered 1.4 Mha in 32 countries (0.7% of Europe’s forest area). Most of these forests were protected (89%), but only 46% of them strictly. Primary forests mostly occurred in mountain and boreal areas and were unevenly distributed across countries, biogeographical regions and forest types. Unmapped primary forests likely occur in the least accessible and populated areas, where forests cover a greater share of land, but wood demand historically has been low.
Main conclusions
Despite their outstanding conservation value, primary forests are rare and their current distribution is the result of centuries of land use and forest management. The conservation outlook for primary forests is uncertain as many are not strictly protected and most are small and fragmented, making them prone to extinction debt and human disturbance. Predicting where unmapped primary forests likely occur could guide conservation efforts, especially in Eastern Europe where large areas of primary forest still exist but are being lost at an alarming pace.
Significance
The strong focus on species extinctions, a critical aspect of the contemporary pulse of biological extinction, leads to a common misimpression that Earth’s biota is not immediately threatened, just slowly entering an episode of major biodiversity loss. This view overlooks the current trends of population declines and extinctions. Using a sample of 27,600 terrestrial vertebrate species, and a more detailed analysis of 177 mammal species, we show the extremely high degree of population decay in vertebrates, even in common “species of low concern.” Dwindling population sizes and range shrinkages amount to a massive anthropogenic erosion of biodiversity and of the ecosystem services essential to civilization. This “biological annihilation” underlines the seriousness for humanity of Earth’s ongoing sixth mass extinction event.
Aim
The aim was to investigate the relationship between climate, topography and soil pH, as well as vegetation structure and the beta diversity of plants, butterflies and birds; and to investigate the correlations of (woody) plant beta diversity with animal beta diversity.
Location
Switzerland (central Europe).
Methods
We used pairwise Sørensen dissimilarity as measure of total beta diversity and partitioned it into its turnover and nestedness components. Variation partitioning was used to assess the independent and cumulative effects of environmental predictors, with vegetation structure being derived from airborne light detection and ranging (LiDAR) data. We also checked for independent effects of plant and woody plant beta diversity on butterfly and bird beta diversity, respectively, and for independent effects of spatial distance on beta diversity.
Results
Climate emerged as the strongest statistical predictor of beta diversity across taxonomic groups, with large independent effects on species turnover. Climate effects were most pronounced for plants, followed by butterflies and birds. We also found large independent effects of vegetation structure on total beta diversity and its turnover component across taxonomic groups, particularly for birds. Plant and woody plant beta diversity substantially improved the predictions of butterfly and bird beta diversity, respectively. Spatial distance had hardly any independent effect on beta diversity.
Main conclusions
Climate is a stronger filter for plant communities than for butterfly and bird communities, which are more affected by vegetation structure, probably owing to associated resources and niches. Vegetation structure is a crucial predictor of beta diversity, and therefore contiguous and detailed 3‐D habitat structure data are highly relevant to further our understanding of niche‐based community assembly. Plant and animal beta diversity appear to be non‐independent, suggesting that differences in the response times of interacting taxa should be accounted for in environmental change impact assessments on biodiversity.
Habitat loss and fragmentation can negatively impact the persistence of dispersal-limited lichen species with narrow niches. Rapid change in microclimate due to canopy dieback exposes species to additional stressors that may limit their capacity to survive and colonize. We studied the importance of old trees as micro-refuges and microclimate stability in maintaining lichen survival and diversity. The study was situated in mountain Norway spruce (Picea abies) forests of the Gorgany Mountains of the Ukrainian Carpathian mountain belt. Lichens were collected on 13 circular study plots (1000 m²). Dendrochronological methods were used to reconstruct age structure and maximum disturbance event history. A linear mixed effects model and general additive models were used to explain patterns and variability of lichens based on stand age and disturbance history for each plot. Tree age was the strongest variable influencing lichen diversity and composition. Recent (<80 years ago) severely disturbed plots were colonized only by the most common species, however, old trees (>200 years old) that survived the disturbances served as microrefuges for the habitat-specialized and/or dispersal limited species, thus epiphytic lichen biodiversity was markedly higher on those plots in comparison to plots without any old trees. Most species were able to survive microclimatic change after disturbances, or recolonize disturbed patches from surrounding old-growth forests. We concluded that the survival of old trees after disturbances could maintain and/or recover large portions of epiphytic lichen biodiversity even in altered microclimates.
Advances in metacommunity theory have made a significant contribution to understanding the drivers of variation in biological communities. However, there has been limited empirical research exploring the expression of metacommunity theory for two fundamental components of beta diversity: nestedness and species turnover. In this paper, we examine the influence of local environmental and a range of spatial variables (hydrological connectivity, proximity and overall spatial structure) on total beta diversity and the nestedness and turnover components of beta diversity for the entire macroinvertebrate community and active and passively dispersing taxa within pond habitats. High beta diversity almost entirely reflects patterns of species turnover (replacement) rather than nestedness (differences in species richness) in our dataset. Local environmental variables were the main drivers of total beta diversity, nestedness and turnover when the entire community was considered and for both active and passively dispersing taxa. The influence of spatial processes on passively dispersing composition, total beta diversity and nestedness was significantly greater than for actively dispersing taxa. Our results suggest that species sorting (local environmental variables) operating through niche processes was the primary mechanism driving total beta diversity, nestedness and turnover for the entire community and active and passively dispersing taxa. In contrast, spatial factors (hydrological connectivity, proximity and spatial eigenvectors) only exerted a secondary influence on the nestedness and turnover components of beta diversity. This article is protected by copyright. All rights reserved.
The concept of 'metacommunity', or a set of local communities linked by dispersal, has gained great popularity among community ecologists over the last decade. However, whereas metacommunity research mostly addresses questions on spatial biodiversity patterns at the regional scale, conservation planning requires quantifying temporal variation in those metacommunities, and the contributions that individual (local) habitats make to regional dynamics. Here we propose that recent advances in diversity partitioning methods may allow for a better understanding of metacommunity dynamics and for the identification of keystone habitats. First, we show how time series of the two components of beta diversity (richness and replacement), and of the contributions of local habitats to these components, can provide valuable insights into metacommunity dynamics. Second, we apply this framework to a time-series data set of a highly-dynamic model system (an intermittent river) to identify which habitats control source-sink dynamics. Finally, we show how overlooking the temporal component of variation in metacommunity structure may lead to underestimating beta diversity, and we discuss how conservation and metacommunity ecology research in highly-dynamic ecosystems could benefit from studying beta diversity components over time. Adequately appraising spatio-temporal variability in community composition, and identifying sites that are pivotal for maintaining biodiversity at the landscape scale, are key needs for conservation prioritization and planning. Our framework may thus guide conservation actions in highly-dynamic ecosystems whenever time-series data describing biodiversity across sites connected by dispersal are available. This article is protected by copyright. All rights reserved.
An ongoing loss of Europe’s old-growth forests urgently calls for improving our understanding of native biodiversity response to habitat changes. Studies disentangling the effects of habitat quantity, quality, and continuity on species diversity are rare, however, understanding the differences between these effects is crucial for forest management and conservation efforts. Here, we investigated the influence of habitat quantity, quality, and continuity on the total and red-listed species richness of wood-inhabiting fungi in old-growth mountain Norway spruce (Picea abies Karst.) forest in Central Europe. The fruitbody-based mycological survey conducted on permanent plots was combined with the measurements of forest structural characteristics such as deadwood volumes (indicating habitat quantity), dimensions, and decay stages (indicating habitat quality). Additionally, precise dendrochronological measurements were used to estimate the mean age of five oldest trees and the number of >250 years-old-trees (i.e., those that survived a probable logging activity about 250 years ago) as indicators of habitat continuity. Our results showed the total species richness of wood-inhabiting fungi to be best correlated with habitat quantity (volume of low snags and lying deadwood), while the red-listed species richness was best explained by habitat continuity indicated by the number of >250 years-old-trees. Our study provides novel evidence regarding uninterrupted habitat continuity being crucial in supporting red-listed fungal species. Stands with preserved habitat continuity (e.g., the absence of clearcutting and deforestation) as well as old-growth stands with long habitat history should be prioritised for conservation. Greater degree of retention forestry practices should be required in production forests to preserve habitat continuity. Our study shows that such decisions are likely to lead to positive effects that can persist for centuries.
Forests are increasingly affected by natural disturbances like fires, insect outbreaks, and windstorms. Such disturbances are commonly followed by salvage logging. Disturbance and salvage logging affect biodiversity by altering microclimate, habitat structure, and deadwood amount. To mitigate possible negative effects of salvage logging on biodiversity, ecologists often recommend the retention of disturbance-created structures. However, the mechanisms through which retained structures affect biodiversity remain largely unknown. We analysed
9,602 individuals of saproxylic beetles belonging to 268 species and 3,172 individuals of aculeate Hymenoptera
belonging to 68 species of cavity-nesters and 126 species of non-cavity-nesters over two years in a wind-disturbed beech forests with various intensity of salvage logging. We quantified the relative importance of canopy openness and deadwood amount. Our final dataset consisted of 268 saproxylic beetle species and 194 species of aculeate Hymenoptera out of which 68 were cavity-nesters and 126 non cavity-nesters. Generalized linear mixed effect models showed the lowest number of Hymenoptera and beetle species in undisturbed forest. Permutational
analysis of variance revealed that treatment and canopy openness drive community composition of both taxa.
Increased canopy openness was the main factor positively affecting numbers of species of aculeate Hymenoptera
and saproxylic beetles in the first two years after the disturbance. Deadwood amount only affected community composition of saproxylic beetles. However, gamma diversity and community composition of saproxylic beetles indicated that disturbed and extensively logged plots resembled disturbed unlogged plots rather than disturbed and intensively logged plots. Our findings suggest that at least some timber might be extracted from disturbed areas, without major losses of biodiversity of saproxylic beetles and aculeate Hymenoptera.
Habitat loss and fragmentation along with altered disturbance regimes cause raptor population declines, but processes, rates and interactions are seldom known. Knowledge gaps remain mainly in large forest-dwelling raptors that use habitats on several spatial scales. Our study focusses on breeding habitats and habitat-associated breeding performance of the Lesser Spotted Eagle (“eagle”) across five spatial scales in Laborecká vrchovina Mts (East Carpathians, Slovakia) during 2011–2016. We calculated two relative measures of breeding performance (breeding attempt index, BAI; nest productivity index, NPI) and related them to habitat characteristics sampled on the nest-platform, nest-tree, nest-site, home-range and landscape scale. We found that eagle‘s breeding performance was best explained by predictors on the home-range and landscape scale. BAI and NPI strongly and consistently increased with increasing distance of nest to the nearest felling site and with occurrence of the nest site on lower slope landforms. Former finding supported ample evidence that logging operations pose a grave threat to eagle’s reproduction, while the latter hinted at its strong preference or even specialization for forest edges, for notably old regional ecotones between montane forests and submontane non-forest formations show lower slope topography. On the nest-site scale, nest productivity (NPI) significantly and strongly increased with increasing percentage of Sessile Oak (Quercus petraea) and decreased with cosine of slope aspect in response to more open and accessible canopy structure resulting from oak appearance in beech-dominated forests and to contrasts in solar radiation, shade and similar north–south effects. On the nest-platform and nest-tree scale breeding performance marginally significantly increased with increasing relative nest height above ground and decreased in nests of natural origin (in BAI). It pointed to unrecognized relevance of relative nest height that may link nest-tree with nest-site scale and reflect a trade-off between nest accessibility and nest protective cover, and to greater nest placement diversity with possible greater vulnerability of natural nests. Differences in breeding performance measured by BAI vs NPI indicated that certain selection pressures may vary significantly during the breeding cycle, e.g., early vs late breeding failures and subsequent learning from negative experience. We recommended several management actions by our results, particularly to advance systematic eagle monitoring, to address multiple scales of its habitat use according to their relative importance, to increase the width of protection zones around nests and adopt new or strengthen existing landscape-scale measures and to follow sustainable forestry as a part of integrated landscape management instead of close-to-nature forestry.
Understanding the processes shaping the composition of assemblages at multiple spatial scales in response to disturbance events is crucial for preventing ongoing biodiversity loss and for improving current forest management policies aimed at mitigating climate change and enhancing forest resilience. Deadwood-inhabiting fungi represent an essential component of forest ecosystems through their association with deadwood decomposition and the cycling of nutrients and carbon. Although we have sufficient evidence for the fundamental role of deadwood availability and variability of decay stages for fungal species diversity, the influence of long-term natural disturbance regimes as the main driver of deadwood quantity and quality has not been sufficiently documented. We used a dendroecological approach to analyse the effect of 250-years of historical natural disturbance and structural habitat elements on local (plot-level) and regional (stand-level) species richness of deadwood-inhabiting fungi. We used data collected from 51 study plots within nine best-preserved primary spruce forest stands distributed across the Western Carpathian Mountains. Historical disturbances shaped the contemporary local and regional species richness of fungi, with contrasting impacts of disturbance regime components at different spatial scales. While local diversity of red-listed species has increased due to higher disturbance frequency, regional diversity of all species has decreased due to higher severity historical disturbances. The volume of deadwood positively influenced the species richness of deadwood-inhabiting fungi while canopy openness had a negative impact. The high number of observed rare species highlights the important role of primary forests for biodiversity conservation. From a landscape perspective, we can conclude that the distribution of species from the regional species pool is-at least to some extent-driven by past spatiotemporal patterns of disturbance events. Natural disturbances occurring at higher frequencies that create a mosaic forest structure are necessary for fungal species-especially for rare and endangered taxa. Thus, both the protection of intact forest landscapes and forest management practises that emulate natural disturbance processes are recommended to support habitats of diverse fungal communities and their associated ecosystem functions.
Large trees (also termed veteran trees or habitat trees) are keystone structures for biodiversity worldwide. Retention forestry aims to keep large trees in production stands to support biodiversity. Nevertheless, there is insufficient information about the effect of large trees on biodiversity and how many large trees should be left in different types of stands, including spruce-dominated production forest. We aimed to investigate the influence of large trees on birds (included generalist and specialist species) in spruce-dominated production forest throughout the Czech Republic while taking into consideration effects of stand age, tree species composition, and distance to a clearing. At 20 study sites (each 600 ha), all trees with diameter at breast height (DBH) ≥ 70 cm were exhaustively searched. We then localized sampling plots representing a gradient of large tree numbers from zero to maximum on each plot. Birds were sampled using point count method in breeding seasons 2018 and 2019. Bird assemblages were analysed using generalized linear mixed models with Poisson error distribution. The total number of birds, number of generalist species, and number of specialist species increased significantly with the number of broadleaved trees ≥ 70 cm DBH. Furthermore, tree species diversity positively affected generalist species and negatively influenced specialist species. Our results suggest that 5 broadleaved trees ≥ 70 cm DBH/ ha greatly improve bird diversity in spruce-dominated production forests and forest management should be adapted to reach ≥ 5 native, large, broadleaved trees to improve structural diversity of spruce-dominated production forests.
Epiphytic and epixylic lichens respond negatively to forest degradation, climate change and pollution, but those effects may depend on functional traits or interact with the stage of tree decay. Disentangling the main drivers of lichen communities remains a challenge in regions where lichens are diverse and poorly known, as the case of Patagonian temperate forests. We used a multi-scale approach to evaluate the relationship between environmental variables, tree decay stage and lichens. We sampled lichens across three increasing scales (tree<<site<<landscape) by selecting 19 landscape units, where trees in four decay stages (snags, logs, cavity trees and healthy trees) were selected within sampling plots. A total of 35 predictors were measured over different scales, including 25 remote sensing indices of forest conditions, climate and air pollutants. Structural Equation Models were used to test the causal linkages of predictors with lichens, distinguishing functional categories (size, growth and reproductive strategy). A total of 69 lichen species were recorded. Cavity trees and logs supported the largest diversity, while snags and healthy trees had the lowest diversity. Functional lichen groups responded differently to fine-scale variables, including the diameter, height, density and pH of trees. Air pollutants affected species with sexual and mixed strategies. Lichens were sensitive to precipitation, temperature and wind speed, with foliose and sexual species responding positively to the latter. The abundance of all species and macrolichens increased with tree senescence and decreased with canopy continuity. Lichens occupying snags and logs responded negatively to primary productivity and tree senescence, but positively to soil organic matter. Our findings suggest: i) the functional structure of lichen communities varies non-linearly with the wood decay process; ii) the reproductive strategy influences the sensitivity to air pollutants, iii) climate variables influence dispersal and colonization of woody substrates; and iv) forest structure/succession interacts with tree decay.
Threats to fungi and fungal diversity throughout the world have prompted debates about whether and how fungi can be conserved. Should it be the site, or the habitat, or the host that is conserved? All of these issues are addressed in this volume, but coverage goes beyond mere debate with constructive guidance for management of nature in ways beneficial to fungi. Different parts of the world experience different problems and a range of examples are presented; from Finland in the North to Kenya in the South, and from Washington State, USA in the West to Fujian Province, China in the East. Equally wide-ranging solutions, are put forward, from voluntary agreements, through land management techniques, to primary legislation. Taken together, these provide useful suggestions about how fungi can be included in conservation projects in a range of circumstances.
Understanding the processes shaping the composition of assemblages in response to disturbance events is crucial for preventing ongoing biodiversity loss in forest ecosystems. However, studies of forest biodiversity responses to disturbance typically analyze immediate or short-term impacts only, while studies relating long-term disturbance history to biodiversity assemblage dynamics are rare. To address this important knowledge gap, we used a dendroecological approach to link natural disturbance history of 250 years (1750-2000) to structural habitat elements and, in turn, to breeding bird assemblages. We used data collected in 2017 and 2018 from 58 permanent study plots within 10 primary spruce forest stands distributed across the Western Carpathian Mountains of Europe. This dataset contained breeding bird counts and environmental variables describing forest density, tree diameter distribution, tree height, tree microhabitats, deadwood quantity and quality, and regeneration. Bird assemblages were significantly influenced by forest structure which was in turn shaped by disturbance dynamics (disturbance frequency, time since the last disturbance and its severity). Early successional species associated with more open habitats were positively influenced by disturbance-related structure (i.e. deadwood-related variables, canopy cover), while some species responded negatively. At the same time, overall abundance, species richness and Shannon diversity of the bird assemblage remained unchanged under variable disturbance histories. Our results support a view of primary spruce forests as a highly dynamic ecosystem, harbouring populations of bird species at all stages of succession despite significant structural changes and shifting patch mosaics over time due to natural disturbances.
Given the global intensification of forest management and climate change, protecting and studying forests that develop free of direct human intervention-also known as primary forests-are becoming increasingly important. Yet, most countries still lack data regarding primary forest distribution. Previous studies have tested remote sensing approaches as a promising tool for identifying primary forests. However, their precision is highly dependent on data quality and resolution, which vary considerably. This has led to underestimation of primary forest abundance and distribution in some regions, such as the temperate zone of Europe. Field-based inventories of primary forests and methodologies to conduct these assessments are inconsistent; incomplete or inaccurate mapping increases the vulnerability of primary forest systems to continued loss from clearing and land-use change. We developed a comprehensive methodological approach for identifying primary forests, and tested it within one of Europe's hotspots of primary forest abundance: the Carpathian Mountains. From 2009 to 2015, we conducted the first national-scale primary forest census covering the entire 49,036 km 2 area of the Slovak Republic. We analyzed primary forest distribution patterns and the representativeness of potential vegetation types within primary forest remnants. We further evaluated the conservation status and extent of primary forest loss. Remaining primary forests are small, fragmented, and often do not represent the potential natural vegetation. We identified 261 primary forest localities. However, they represent only 0.47% of the total forested area, which is 0.21% of the country's land area. The spatial pattern of primary forests was clustered. Primary forests have tended to escape anthropogenic disturbance on sites with higher elevations, steeper slopes, rugged terrain, and greater distances from roads and settlements. Primary forest stands of montane mixed and subalpine spruce forests are more abundant compared to broadleaved forests. Notably, several habitat types are completely missing within primary forests (e.g., floodplain forests). More than 30% of the remaining primary forests are not strictly protected, and harvesting occurred at 32 primary forest localities within the study period. Almost all logging of primary forests was conducted inside of protected areas, underscoring the critical status of primary forest distribution in this part of Europe. Effective conservation strategies are urgently needed to stop the rapid loss and fragmentation of the remaining primary forests. Our approach based on precise, field-based surveys is widely applicable and transferrable to other fragmented forest landscapes.
Evidence is increasing for positive effects of α-diversity on ecosystem functioning. We highlight here the crucial role of β-diversity - a hitherto underexplored facet of biodiversity - for a better process-level understanding of biodiversity change and its consequences for ecosystems. A focus on β-diversity has the potential to improve predictions of natural and anthropogenic influences on diversity and ecosystem functioning. However, linking the causes and consequences of biodiversity change is complex because species assemblages in nature are shaped by many factors simultaneously, including disturbance, environmental heterogeneity, deterministic niche factors, and stochasticity. Because variability and change are ubiquitous in ecosystems, acknowledging these inherent properties of nature is an essential step for further advancing scientific knowledge of biodiversity-ecosystem functioning in theory and practice.
The book is written in German.
Teil 1. Makromyzeten.
Zusammenfassung
Dieses Buch ist ein Verzeichnis aller in Österreich bisher festgestellten Basidienpilze (Basidiomycota) mit Ausnahme der Rost- und Brandpilze und zudem der Becherpilze (Pezizales) aus der Abteilung der Schlauchpilze (Ascomycota). Diese Pilzgruppen bilden mit freiem Auge gut sichtbare Fruchtkörper und werden deshalb als „Makromyzeten“ (Großpilze) bezeichnet. Ein solches Artenverzeichnis kann keinen Anspruch auf Vollständigkeit erheben. Jedoch wurde durch aufwändige Recherchen, die Zuarbeit vieler Datenbringer und eine hohe Sorgfalt bei der Erstellung der Liste versucht, eine annähernde Vollständigkeit zu erzielen.
Das Verzeichnis beinhaltet insgesamt über 4.450 Pilztaxa (4.100 Arten, 260 Varietäten und 100 Formen) und dokumentiert damit den hohen Anteil der Pilze an der Artenvielfalt Österreichs. Es ist der erste Artenkatalog für Großpilze Österreichs in diesem Umfang.
Das Verzeichnis basiert auf der „Datenbank der Pilze Österreichs“ mit exakt 475.013 gespeicherten Pilznachweisen von 13.652 Fundorten in Österreich bzw. aus 443 Datenquellen (Stand vom September 2016). Weniger als 1.000 Pilzarten (21 %) sind in Österreich „häufig bis sehr häufig“, etwa 1.700 Arten (38 %) sind „verbreitet bis mäßig häufig“, etwa 1.300 Arten (30 %) sind „selten“ und beinahe 500 Arten (11 %) sind in Österreich nur von einem einzigen Nachweis bekannt.
Im Verzeichnis werden für jede Pilzart neben dem wissenschaftlichen und dem deutschen Pilznamen folgende Informationen angeführt: Zuordnung zu einer Formengruppe und zu einer ökologischen (trophischen) Gruppe, allfällige Bindung an eine Pflanzengattung, Häufigkeit in Österreich innerhalb bzw. außerhalb des Alpenraums, Vorkommen in den Bundesländern, Anzahl der älteren (vor 1990) und der neueren Fundorte (seit 1990). Eine umfangreiche Liste von synonymen Pilznamen mit der Referenz zum jeweils aktuellen Pilznamen im Verzeichnis ist angefügt. Das Literaturverzeichnis inkludiert alle vorliegenden und ausgewerteten Datenquellen zu Pilznachweisen in Österreich.
Gleichzeitig wird in diesem Buch eine völlig neu bearbeitete Version der Roten Liste gefährdeter Pilze Österreichs vorgelegt. Von den über 4.450 Pilzarten im vorliegenden Verzeichnis müssen ca. 1.300 Arten (= 29 %) als gefährdet, stark gefährdet oder vom Aussterben bedroht gelten, weitere 790 Arten (= 17 %) als potentiell gefährdet. Die aktuelle Rote Liste umfasst daher insgesamt 2.086 Arten (= 46 %) und ist direkt in das Gesamtverzeichnis aller Pilzarten integriert.
Für jede gefährdete Pilzart werden steckbriefartig die Naturräume (Regionen in Österreich) sowie die gefährdeten Lebensräume aufgezählt, in denen die Art vorkommt, für jede stark gefährdete Pilzart werden außerdem die einzelnen Nachweise (Funde) in Österreich exemplarisch angeführt und die Gefährdungssituation kommentiert. Viele der gefährdeten Pilzarten sowie ihre gefährdeten Lebensräume werden mit Farbfotos abgebildet.
Die Gefährdungsgrade werden sowohl nach dem herkömmlichen und bewährten System mit den Kategorien 0 bis 4 angegeben, als auch mit IUCN-Kategorien. Die Hauptkriterien für die Bewertung des Gefährdungspotenzials sind, neben verschiedenen anderen Risikofaktoren, die Verbreitungsdichte in Österreich (Anzahl der neueren Fundorte) sowie die Bindung an gefährdete Lebensräume (entsprechend der „Liste der gefährdeten Biotoptypen Österreichs“).
Die Pilzarten der Kategorien 0 bis 3 verteilen sich auf neun Gruppen von Lebensraum-Typen wie folgt: 1. Lebensräume der Auen (180 Arten), 2. Moore und weitere Feuchtlebensräume (230 Arten), 3. Grasländer und Offenland-Lebensräume (200 Arten), 4. Laubwälder der kollinen und submontanen Stufe (200 Arten), 5. Mischwälder der montanen Stufe (140 Arten), 6. Lebensräume der hochmontanen und subalpinen Stufe (110 Arten), 7. Lebensräume der alpinen Stufe (100 Arten), 8. Synanthrope Gehölz-Lebensräume (wenige Arten), 9. Weitere Lebensräume (80 Arten).
Als hauptsächliche Ursachen für die Gefährdung der Pilzarten Österreichs werden folgende Faktoren erläutert: Gefährdungsfaktoren, Eutrophierung (Überangebot an Nährstoffen), Vernichtung von Lebensräumen, verminderte ökologische Wertigkeit von Lebensräumen, Zufallsereignisse und Auswirkungen der Klimaerwärmung.
Der Schutz gefährdeter Pilzarten betrifft verschiedene Ebenen, drei Bereiche werden besonders hervorgehoben und diskutiert: Strukturelle Maßnahmen am Standort (besonders in Wäldern), Artenkenntnis, Bildung und Öffentlichkeitsarbeit sowie Internationale Schutzbestrebungen.
In Bezug auf die in Österreich gerne gesammelten Speisepilze wird festgestellt, dass – unter Berücksichtigung der maßgeblichen Kriterien – für die gängigen und beliebtesten Speisepilzarten (mit Ausnahme des Kaiserlings) aktuell keine Gefährdung im Sinne der Roten Liste besteht.
Einen umfangreichen Teil dieses Buches nehmen schließlich statistische Auswertungen ein. Dabei wird die Anzahl der Pilzarten in Österreich, sowie speziell die Anzahl der Rote Liste-Arten, nach zahlreichen verschiedenen Parametern analysiert: Systematische Gruppen, Jahrzehnte (Dekaden), Jahre, Bundesländer, biogeografische Regionen, naturräumliche Regionen, Höhenstufen, Meereshöhen, Klimatypen, Niederschlag, Temperatur, Gesteinsuntergrund (Karbonat bzw. Silikat), ökologische Gruppen, assoziierte Pflanzengattungen insgesamt bzw. speziell für substratgebundene Pilzarten, Monate und Wochen im Jahresverlauf. Am Beispiel von Schutzgebieten, einschließlich aller Nationalparks Österreichs, wird dargestellt, wie sehr die Anzahl der nachgewiesenen Arten (speziell die Zahl der aus einem Gebiet bekannten gefährdeten Pilzarten) von einer hohen oder geringen Untersuchungsintensität abhängen.
Eine Liste von über 100 Personen ist angefügt, die bei einer größeren Anzahl von Pilznachweisen als Finder (Beobachter, Sammler) genannt sind; sie haben maßgeblich zur Entstehung dieses Verzeichnisses beigetragen.
Abstract:
part 1. Macromycetes
This book presents a list of almost all basidiomycetes (Basidiomycota), which have been found in Austria, except rust and smut fungi, and discomycetes (Pezizales, Ascomycota). These fungal groups form fruit bodies well-visible with the naked eye and are therefore referred to as "macromycetes" (large mushrooms).
The list contains a total of 4,450 Pilztaxa (4,100 species, 260 varieties and 100 forms), thus documenting the high percentage of the fungi within the species biodiversity of Austria. It is the first species catalogue for macromycetes in Austria to this extent.
The list is based on the "Database of fungi in Austria" with exactly 475,013 fungal records from 13,652 localities in Austria and from 443 data sources (as of September 2016). In Austria, less than 1,000 species (21%) are "frequent to very frequent", about 1,700 species (38%) are "widespread to moderately frequent", about 1,300 species (30%) are "rare" and almost 500 species (11 %) are only known from one single record.
In addition to the scientific and the German fungus name, the following information is given for each species: allocation to a systematic group in broad sense and an ecological (trophic) guild, possible binding to a plant genus, frequency in Austria within or outside the Alpine area, occurrence in the federal states, number of older (before 1990) and more recent localities (since 1990). An extensive list of synonyms with reference to the current fungal name in the list is attached. The literature lists all available and evaluated data sources of fungal records in Austria.
At the same time, this book presents a completely revised version of the Red List of endangered fungi in Austria. Of the more than 4,450 species of fungi in the present list, approximately 1,300 species (= 29%) are vulnerable, endangered, critically endangered or regionally extinct, while 790 species (= 17%) are near threatened. The actual red list thus comprises a total of 2,086 species (= 46%) and is integrated directly into the list of all macromycetes.
For each endangered fungus species, the natural habitats (regions in Austria) as well as the vulnerable habitats are listed, in which the species occurs, for each endangered or critically endangered species the individual records (finds) in Austria are exemplarily given and the threat situation is commented. Many of the endangered species and their endangered habitats are illustrated with colour photos.
The categories are indicated both by the conventional and proven system with the categories 0 to 4, as well as with IUCN categories. In addition to various other risk factors, the main criteria for the assessment of the potential threat are the distribution density in Austria (number of recent localities) and their binding to endangered habitats (according to the "list of endangered biotope types in Austria").
The fungal species of categories 0 to 3 are distributed among nine groups of habitat types as follows: 1. Habitats of the floodplain (180 species), 2. Bogs and other moist habitats (230 species), 3. Grasslands and open land habitats (200 species), 4. Deciduous forests of the colline and submontane altitudinal zone (200 species), 5. Mixed forests of the montane zone (140 species), 6. Habitats of the upper montane and subalpine zone (110 species), 7. Habitats of the alpine zone (100 species), 8. Synantrop bosk habitats (few species), 9. Other habitats (80 species).
The following factors are elucidated as the main reasons of threat to Austria's fungal species: risk factors, eutrophication (over-supply of nutrients), destruction of habitats, reduced ecological value of habitats, random events and effects of climate warming.
The protection of endangered fungal species affects different fields; three of them are highlighted and discussed: Structural measures at the site (especially in forests), species awareness, education and public relations as well as international conservation efforts.
With regard to the edible mushrooms collected in Austria, it can be stated that - given the relevant criteria - there is currently no danger for the most popular mushrooms in the sense of the red list (except Amanita caesarea).
Finally, a comprehensive section of this book contains statistical evaluations. The number of fungal species in Austria, as well as the number of red list species, is analysed according to numerous different parameters: systematic groups, decades, years, federal states, biogeographical regions, nature regions, altitudinal zones, altitude, climate types, rainfall, temperature, bedrock (carbonate or silicate), ecological groups, associated plant genera in general or especially for substrate-bound fungi, months and weeks in the course of the year. Using the example of protected areas, including all national parks in Austria, it is shown to which extent the number of species reported (especially the number of endangered fungal species known from a locality) depends on a high or low intensity of investigation.
A list of more than 100 persons is attached, which are recorded as a finder (observer, collector) for a larger number of fungal data; they have contributed significantly to the development of this list.
Aim. The number of studies investigating the nestedness and turnover components of beta diversity has increased substantially. Yet, our general understanding of the drivers of turnover and nestedness remains elusive. Here, we examined the effects of species traits, spatial extent, latitude and ecosystem type on the nestedness and turnover components of beta diversity.
Location. Global.
Time period: 1968-2017.
Major taxa studied: From bacteria to mammals.
Methods. From the 99 studies that partition total beta diversity into its turnover and nestedness components, we assembled 269 and 259 data points for the pairwise and multiple site beta diversity metrics, respectively. Our data covered a broad variation in species dispersal type, body size and trophic position. The data were from freshwater, marine and terrestrial realms, and encompassed geographical areas from the tropics to near polar regions. We used linear modelling as a meta-regression tool to analyze the data.
Results. Pairwise turnover, multiple site turnover and total beta diversity all decreased significantly with latitude. In contrast, multiple site nestedness showed a positive relationship with latitude. Beta diversity components did not generally differ among the realms. The turnover component and total beta diversity increased with spatial extent, whereas nestedness was scale-invariant for pairwise metrics. Multiple site beta diversity components did not vary with spatial extent. Surprisingly, passively dispersed organisms had lower turnover and total beta diversity than flying organisms. Body size showed a relatively weak relationship with beta diversity, but had important interactions with trophic position, thus also affecting beta diversity via interactive effects. Producers had significantly higher average pairwise turnover and total beta diversity than carnivores.
Main conclusions. The present results provide evidence that species turnover, being consistently the larger component of total beta diversity, and nestedness are related to the latitude of the study area and intrinsic organismal features. We showed that two beta diversity components had generally opposing patterns with regard to latitude. We highlight that beta diversity partition may give additional insights into the underlying causes of spatial variability in biotic communities compared with total beta diversity alone.
Diversity of forest macrofungal communities is strongly influenced by various management approaches. These effects have so far only been studied in certain types of forest stands and with limited sampling effort. Here we studied the fruit bodies of all macrofungal trophic groups on 80 permanent plots (2500 m² each) in forest stands differing in tree species composition and management practice. Unmanaged forests were shown to be the species-richest at the plot scale and also when the total fungal species richness of the studied forest types was compared. Diversity patterns varied between functional groups – unmanaged forests stand out in richness of wood-inhabiting fungi, while ectomycorrhizal species were more diverse in managed stands. Terrestrial saprotrophic species were similarly highly diverse in both managed and unmanaged mixed forest stands. The highest number of indicator species, predominantly wood-inhabiting fungi, was associated with unmanaged stands. We discuss a list of the most faithful indicator species along with their substratum preferences.