Diversity Of Forest Ecosystems Research Articles

Association between Soil Physicochemical Properties and Bacterial Community Structure in Diverse Forest Ecosystems.

Although the importance of the soil bacterial community for ecosystem functions has long been recognized, there is still a limited understanding of the associations between its community composition, structure, co-occurrence patterns, and soil physicochemical properties. The objectives of the present study were to explore the association between soil physicochemical properties and the composition, diversity, co-occurrence network topological features, and assembly mechanisms of the soil bacterial community. Four typical forest types from Liziping Nature Reserve, representing evergreen coniferous forest, deciduous coniferous forest, mixed conifer-broadleaf forest, and its secondary forest, were selected for this study. The soil bacterial community was analyzed using Illumina MiSeq sequencing of 16S rRNA genes. Nonmetric multidimensional scaling was used to illustrate the clustering of different samples based on Bray-Curtis distances. The associations between soil physicochemical properties and bacterial community structure were analyzed using the Mantel test. The interactions among bacterial taxa were visualized with a co-occurrence network, and the community assembly processes were quantified using the Beta Nearest Taxon Index (Beta-NTI). The dominant bacterial phyla across all forest soils were Proteobacteria (45.17%), Acidobacteria (21.73%), Actinobacteria (8.75%), and Chloroflexi (5.06%). Chao1 estimator of richness, observed ASVs, faith-phylogenetic diversity (faith-PD) index, and community composition were distinguishing features of the examined four forest types. The first two principal components of redundancy analysis explained 41.33% of the variation in the soil bacterial community, with total soil organic carbon, soil moisture, pH, total nitrogen, carbon/nitrogen (C/N), carbon/phosphorous (C/P), and nitrogen/phosphorous (N/P) being the main soil physicochemical properties shaping soil bacterial communities. The co-occurrence network structure in the mixed forest was more complex compared to that in pure forests. The Beta-NTI indicated that the bacterial community assembly of the four examined forest types was collaboratively influenced by deterministic and stochastic ecological processes.

The diversity of epixylic bryophytes in relation to dead wood properties and forest management in New Brunswick, Canada

Rotting wood is widely recognized as an important feature for bryophyte diversity in forest ecosystems but forest management practices, focused on high yields, have led to widespread reductions in the quantity and quality of coarse woody debris (CWD). As a result, many epixylic specialists are now uncommon or threatened throughout much of their former ranges. How much CWD is required to maintain desirable biodiversity, and which qualities of CWD do this most effectively is still to be answered. To address this, we analyzed two datasets from mid-rotation and mature plantations from the same landscape to better understand how the epixylic community varies with stand age, wetness, silvicultural treatment, and the abundance and type of CWD. Mature stands were either partially cut with a strip-cut treatment or were untreated. Mid-rotation plantations had a higher richness of non-Sphagnum mosses and liverworts than mature plantations. Both plantation types had a similar Simpson’s diversity indices, but these were lower than those of treated and untreated mature white cedar stands and untreated mature softwood stands. While composition of both plantation types was similar, only mature plantations differed significantly from other stand types. We speculate that this discrepancy between mid-rotation plantations and mature plantations was due to better soil drainage and a longer duration of intensive management in mature plantations, leading to reduced CWD abundance, and therefore to reduced bryophyte diversity. Our results revealed a clear positive relationship between total CWD surface area and liverwort richness and diversity in xeric sites while no relation was detected in mesic sites. More CWD is better in the case of xeric sites, where apparent asymptote of diversity is near the maximum total CWD detected in these stands. Because canopy composition and humidity also had a significant influence on bryophyte diversity and composition, further studies are needed to clearly identify thresholds of CWD surface area that take into account different stand types, soil moisture, fertility regimes, or with regards to the ecosystem in which the managed stands occurs.

Characterization and Carbon Sequestration Potential of Sacred Forests in the Western Highlands Cameroon

Cameroon has a diversity of forest ecosystems, including sacred forests that have been preserved until now by traditional laws. The aim of this study was to characterize the vegetation of two sacred forests in the Western Highlands and to estimate the quantities of carbon stored by these forests. The inventories were carried out in 24 quadrats measuring 30 m x 30 m installed in the Bansoa and Baloum forests according to their surface area. Individuals with a diameter of 10 cm or more at breast height (1.30 m from the ground) were measured. Phytodiversity was assessed using the Shannon and Simpson indixes. The quantities of carbon stored by the sacred forests were obtained using allometric equations developed by other researchers and appropriate to the tropical zone. Overall, 50 species in 31 genera and 25 families were recorded. The diversity index values are low. They range from 1.47 to 2.52 bits per plot for the Shannon index, and from 0.70 to 0.91 for the Simpson index. Markhamia lutea and Cola acuminata are the most frequent and abundant species in the study area. The densities of individuals per hectare are 368 individuals/ha at Bansoa and 416 individuals/ha at Baloum and the basal area varies from 32.37 m2/ha to 38.44 m2/ha. The shrub layer dominates in both forests. Of the species recorded, 03 are Vulnerable and 02 are Endangered. Carbon sequestration was 286.84 t C/ha at Baloum and 232.44 t C/ha at Bansoa, with CO2 uptake of 1052.12 t CO2/ha and 853.55 t CO2 /ha respectively. The results of this study show that despite their small size, sacred forests play a significant role in the conservation of plant diversity and also help to reduce greenhouse gases in nature.

Dynamics and Prospects for Forestry Development in Russia and China: Cross-Country Comparisons

The purpose of the study is to assess the possibility of changing the trade exchange of timber products between Russia and China, caused by external circumstances. First, the growing sanctions pressure on both countries; secondly, the cessation of roundwood exports from Russia to China from the beginning of 2022, which accounted for up to 60 % of the total foreign trade turnover in timber products between the countries; thirdly, a special military operation of Russia since February 2022. All this led to a severance of logistical and financial ties and complicated the economic state of the forest complex of both countries in 2022. The article identifies and analyzes the most significant indicators that affect the efficiency of the development of forestry in Russia and China, as the basis of the forest industry. Including dynamics and trends in forest areas in both countries for 2010– 2021. which made it possible to show their multidirectional nature: in Russia, forest areas decreased by 0.37 %, in China - increased by 9.87 %. This indicates that contradictions between the owner of the forest and the forest business are growing in Russia, and vice versa in China. It has been established that the total forest reserves in Russia are 4.7 times greater than in China, and the forest reserves per hectare of forest area are 1.35 times greater. This is the competitive advantage of Russian forests. But the study of the trend of their changes indicates a reduction in forest reserves over the study period in Russia, and an increase in China. The quality of forest management in our country needs to be improved. It is noted that Russian and Chinese forests have been degraded. The reasons for this are different. Different outcomes and factors influencing reforestation in the countries studied. It is shown that in Russia during the study period, not only deforestation was observed, but also forest degradation, i.e. deterioration of the species composition, reduction of the species diversity of forest ecosystems. The studied dynamics and trends in the parameters of development of the forestry sector of the two countries made it possible to determine the directions for deepening economic cooperation in the field of forestry relations in the context of sanctions pressure on Russia and China, aimed at their expansion, taking into account the observance of mutual interests.

Long-term N addition reduced the diversity of arbuscular mycorrhizal fungi and understory herbs of a Korean pine plantation in northern China

With the development of agriculture and industry, the increase in nitrogen (N) deposition has caused widespread concern among scientists. Although emission reduction policies have slowed N releases in Europe and North America, the threat to biodiversity cannot be ignored. Arbuscular mycorrhizal (AM) fungi play an important role in the establishment and maintenance of plant communities in forest ecosystems, and both their distribution and diversity have vital ecological functions. Therefore, we analyzed the effects of long-term N addition on AM fungi and understory herbaceous plants in a Korean pine plantation in northern China. The soil properties, community structure, and diversity of AM fungi and understory herbaceous plants were detected at different concentrations of NH4NO3 (0, 20, 40, 80 kg N ha−1 year−1) after 7 years. The results showed that long-term N deposition decreased soil pH, increased soil ammonium content, and caused significant fluctuations in P elements. N deposition improved the stability of soil aggregates by increasing the content of glomalin-related soil protein (GRSP) and changed the AM fungal community composition. The Glomus genus was more adaptable to the acidic soil treated with the highest N concentration. The species of AM fungi, understory herbaceous plants, and the biomass of fine roots were decreased under long-term N deposition. The fine root biomass was reduced by 78.6% in the highest N concentration treatment. In summary, we concluded that long-term N deposition could alter soil pH, the distribution of N, P elements, and the soil aggregate fractions, and reduce AM fungal and understory herb diversity. The importance of AM fungi in maintaining forest ecosystem diversity was verified under long-term N deposition.

Representation of in situ forest genetic resources of broadleaf tree species according to forest types in the Right-Bank Forest-Steppe of Ukraine

The article analyzes the formation and localization of in situ forest genetic resource conservation facilities in the conditions of the Right Bank Forest-Steppe of Ukraine in terms of the main forest types. Peculiarities of the state and selection structure of the forest genetic reserves (FGR) and plus stands (PS) were studied. The established that the largest area of forest genetic reserves and plus stands of broadleaves forests within the Right Bank Forest-Steppe is concentrated in the Vinnytsia region, based on the results of the research. The largest number and largest areas of these objects are concentrated in this region. It was established that the largest area of FGR located in fresh forest type conditions — 3475.9 ha, according to the distribution of forest genetic reserves and plus stands. The largest number of objects — 92 (78.0%) — is concentrated in this type of forest. The largest area of FGR is concentrated in fresh hornbeam beech — 842.3 ha in the Roztoch-Opil district of the forest typological region. There are 44 genetic reserves located in the conditions of the Podilsk sector of the Polysk-Prikarpattia district of wet hornbeam forests of the forest typological region of the wet cluster 3d. The largest area of forest stands is fresh beech forest — 234.0 ha. There are 40 FGR with a total area of 2,001 hectares of fresh hornbeam forests in the Podilskyi and Pravoberezhny sectors of the Dnipro tipologycal district. Forest genetic reserves are mainly concentrated in fresh hornbeam forest — 1584.6 hectares (29 units). The representation of the objects of in situ conservation of the gene pool of forest tree species in terms of forest types is insufficient and reflects only 16% of the entire diversity of forest ecosystems within the boundaries of the Roztoch-Opil district and 21–24% of the Dnipro districts of Polisko-Prikarpatskiy. This requires the introduction of measures for the additional creation of forest genetic reserves in other types of forest with the aim of the widest possible representation of the ecosystem diversity of the forest landscapes of the region.

Armillaria altimontana in North America: Biology and Ecology.

Armillaria altimontana is a fungus (Basidiomycota, Agaricomycetes, Agaricales, and Physalacriaceae) that is generally considered as a weak/opportunistic pathogen or saprophyte on many tree hosts. It widely occurs across the northwestern USA to southern British Columbia, Canada, but relatively little is known about its ecological role in the diverse forest ecosystems where it occurs. This review summarizes the biology and ecology of A. altimontana, including its identification, life cycle, distribution, host associations, and bioclimatic models under climate change.

Improving Forest Detection Using Machine Learning and Remote Sensing: A Case Study in Southeastern Serbia

Vegetation plays an active role in ecosystem dynamics, and monitoring its patterns and changes is vital for effective environmental resource management. This study explores the possibility of machine learning techniques and remote sensing data to improve the accuracy of forest detection. The research focuses on the southeastern part of the Republic of Serbia as a case study area, using Sentinel-2 multispectral bands. The study employs publicly accessible satellite data and incorporates different vegetation indices to improve classification accuracy. The main objective is to examine the practicability of expanding the input parameters for forest detection using a machine learning approach. The classification process is performed by employing support vector machines (SVM) algorithm and utilising the SVM module in the scikit-learn package. The results demonstrate that including vegetation indices alongside the multispectral bands significantly improves the accuracy of vegetation detection. A comprehensive assessment reveals an overall classification accuracy of up to 99.01% when the selected vegetation indices (MCARI, RENDVI, NDI45, GNDVI, NDII) are combined with the Sentinel-2 bands. This research highlights the potential of machine learning and remote sensing in forest detection and monitoring. The findings underscore the importance of incorporating vegetation indices to enhance classification accuracy using the Python programming language. The study’s outcomes provide valuable insights for environmental resource management and decision-making processes, particularly in regions with diverse forest ecosystems.

Changes to relative stand composition after almost 50 years of Heterobasidion root disease in California true fir and pine forests

AbstractThe Agaricomycete Heterobasidion annosum sensu lato (s.l.), a species complex of fungal pathogens, causes root and butt rot on conifers throughout the northern hemisphere, thereby shaping structure, composition, and evolution of vast and diverse forest ecosystems. We analyze forest change 48–49 years following Heterobasidion root disease emergence in 63 permanent plots first established in 1970–1972 and measured at least once every decade through 2020. We use this dataset to infer the long‐term consequences of Heterobasidion root disease in a set of common forest types that reflect some of the most important hosts for this set of diseases in western North America. We contrasted three host–pathogen systems located within the Sierra Nevada, southern Cascades Mountain Range and the Modoc Plateau: (1) H. irregulare in host communities dominated by several Pinus (pine) species and Calocedrus decurrens (incense cedar) in Yosemite Valley, on the Sierra Nevada Range western slope; (2) H. irregulare in a largely single species (Pinus jeffreyi) host disease system on the eastern slopes of the Sierra Nevada and southern Cascades as well as the Modoc Plateau; and (3) H. occidentale—also on the western slope of the Sierra Nevada—in stands with a mixture of susceptible Abies (true fir) and a diversity of non‐hosts for this Heterobasidion species. Approximately 50 years after disease emergence, relative basal area and stem density were significantly reduced within disease centres in all three pathosystems, but changes to forest composition and relative species dominance were determined by pre‐disease host and non‐host diversity. In the western‐slope H. occidentale system, the disease increased the dominance of non‐susceptible species, Pinus species and C. decurrens. In the multi‐genus Yosemite pathosystem, H. irregulare did not significantly shift species dominance, and as expected, species shifts did not occur in the largely single‐genus eastern‐slope forests. In these widespread California forest ecosystems, two factors appeared to determine forest conditions almost 50 years after Heterobasidion root disease monitoring: the size of the disease centre and the initial diversity of non‐hosts. Along with pathogen species, these factors appear to affect the local severity of disease as well as the degree of species shifts relative to initial plot compositions, reaffirming host susceptibility classifications associated with these forest types.

Windstorm disturbance sets off plant species invasion, microbiota shift, and soilborne pathogens spread in an urban Mediterranean forest

We investigated the effects of a severe windstorm on vegetation, soil chemistry, understory microclimate, and soil microbiota in a Mediterranean holm oak forest. Plant species composition remained almost unchanged in the undisturbed area, whereas highly diverse plant communities were found in the disturbed area (e.g. gap area). Specifically, 11 invasive plant species were detected in 2015, but four years after, five disappeared and another five decreased, with only Ailanthus altissima increasing. Soil in disturbed areas has higher pH, Na, P, K, Ca, Cu, and Mn, but lower total limestone, organic carbon, total nitrogen, Mg, Fe, and standing litter compared to undisturbed areas. Disturbed areas had higher light availability at the ground and large variations in soil and air temperature and air relative humidity compared to undisturbed areas. The storm disturbance increased soil bacterial and fungal species richness and diversity. Moreover, the microbial co-occurrence network in the undisturbed area was more heterogeneous and complex, while modularity and number of positive correlations were higher in the disturbed area, which suggests that the structural composition of microbial communities and their co-occurrence patterns have been altered by windstorm disturbance. In the gaps, soil microbial community composition indicated a shift toward an opportunistic microbiota dominated by fast-growing but less competitive species. In addition, we found a large increase in putative plant pathogens but a decrease in simbiotrophic and ectomycorrhizal fungi in the gaps. The present work demonstrate the multiple effects of storm damage on the above- and belowground structure and diversity of forest ecosystems.

Abundance and diversity of soil arthropods in the secondary forest and park at the University of Bengkulu

Soil ecosystems are ecosystems related to the degradation of organic matter. University of Bengkulu is an area that has two kinds of soil ecosystems; secondary forest ecosystems and park ecosystems. Arthropods are one of the faunas living in the University of Bengkulu campus ecosystem. Camponotus dominates the secondary forest area, while Solenopsis dominates the park ecosystem. Data were obtained from two ecosystems (secondary forest ecosystem and park ecosystem). The results show that there are five classes with 199 individuals, while in the park ecosystem, there are four classes with 250 individuals.The secondary forest ecosystem diversity index value is 2,73, and the ecosystem diversity index value is 1,91. The evenness index value of the secondary forest ecosystem is 0,78, and the park ecosystem is 0,76. The secondary forest ecosystem dominance index value is 0,09, and the park ecosystem dominance index is 0,17. The diversity of soil arthropods in secondary forest and park ecosystems is in the category of moderate diversity. The even distribution of soil arthropods in both ecosystems is high. Moreover, there is no dominance by one type of soil arthropods in both ecosystems. The diversity of arthropods in the secondary forest ecosystem is higher than that of the park ecosystem. The number of individuals in the park ecosystem is higher than in the secondary forest ecosystem. In both ecosystems, the most commonly found are from the Formicidae family

LiDAR GEDI derived tree canopy height heterogeneity reveals patterns of biodiversity in forest ecosystems

The “Height Variation Hypothesis” is an indirect approach used to estimate forest biodiversity through remote sensing data, stating that greater tree height heterogeneity (HH) measured by CHM LiDAR data indicates higher forest structure complexity and tree species diversity. This approach has traditionally been analyzed using only airborne LiDAR data, which limits its application to the availability of the dedicated flight campaigns. In this study we analyzed the relationship between tree species diversity and HH, calculated with four different heterogeneity indices using two freely available CHMs derived from the new space-borne GEDI LiDAR data. The first, with a spatial resolution of 30 m, was produced through a regression tree machine learning algorithm integrating GEDI LiDAR data and Landsat optical information. The second, with a spatial resolution of 10 m, was created using Sentinel-2 images and a deep learning convolutional neural network. We tested this approach separately in 30 forest plots situated in the northern Italian Alps, in 100 plots in the forested area of Traunstein (Germany) and successively in all the 130 plots through a cross-validation analysis. Forest density information was also included as influencing factor in a multiple regression analysis. Our results show that the GEDI CHMs can be used to assess biodiversity patterns in forest ecosystems through the estimation of the HH that is correlated to the tree species diversity. However, the results also indicate that this method is influenced by different factors including the GEDI CHMs dataset of choice and their related spatial resolution, the heterogeneity indices used to calculate the HH and the forest density. Our finding suggest that GEDI LIDAR data can be a valuable tool in the estimation of forest tree heterogeneity and related tree species diversity in forest ecosystems, which can aid in global biodiversity estimation.

Anthropogenic disturbances alter responses of understory plants to deer density: A 9-year deer density control experiment

The increasing deer population and their expanding distribution have altered the diversity and biomass of the plant community in the northern hemisphere. Furthermore, anthropogenic disturbances such as nitrogen deposition and logging threaten plant diversity in many parts of the forests. Therefore, it is necessary to investigate the effects of deer on plant communities under nitrogen deposition and logging conditions to understand and conserve plant diversity in forest ecosystems. We conducted a field experiment that controlled three levels of deer densities (exclosure: 0 deer/km2, low: 10 deer/km2, and high: 20 deer/km2) and four anthropogenic disturbances (without anthropogenic disturbances [control], nitrogen addition, logging, and nitrogen addition and logging combined) in a cool temperate secondary forest in northern Japan for nine years. We surveyed the effects of deer density and anthropogenic disturbance treatments on species richness and vegetation cover of life forms (forbs, ferns, trees, graminoids, unpalatable species, vines, and shrubs) and all species of understory vascular plants. We estimated the constant effect (without the elapsed year) and the temporary effect (with the elapsed year) of deer density, anthropogenic disturbances, and their interactions on the species richness, vegetation cover, and Simpson’s index as separate parameters in full models and selected the best model. The high deer density negatively affected the species richness of some life forms and all species and accelerated these effects over time for all species. The vegetation covers of most of the life forms were negatively affected by high deer density, and the effect was reduced over time. In contrast, the exclosure negatively affected the species richness of some life forms and positively affected the vegetation cover of most of the life forms and all species. The effect on the cover accelerated over time. Nitrogen addition accelerated the negative effect of high deer density on the species richness of shrubs. On the other hand, logging reduced the negative effect of high deer density on the species richness of all species. The cover of unpalatable species in the high deer density site with logging was approximately nine times higher than that in the high deer density site without anthropogenic disturbances in the last surveyed year. The high deer density and logging decreased the Simpson’s diversity index score. These results indicate that the effects of deer density, anthropogenic disturbances, and their interactions vary with time. These interactions must be considered to manage deer’s effect on forest ecosystems.

Estimating the amount of British Columbia’s “big-treed” old growth: Navigating messy indicators

British Columbia’s (BC) diverse forest ecosystems include highly productive old growth with global importance for carbon storage and biodiversity. Current estimates of the remaining amount of “big-treed” old growth vary 10-fold, creating uncertainty that challenges provincial attempts to shift management policy toward ecological integrity. This uncertainty arises from using different remotely sensed indicators and definitions of tree size. No ideal indicator exists. We attempt to improve clarity by evaluating the reliability of candidate indicators, calibrating selected indicators to improve consistency, and generating multiple estimates of the amount of big-treed old growth using calibrated indicators. To evaluate reliability, we compared inventory estimates of tree size and site productivity with measured tree size in 1,945 ground plots. To assess the amount of big-treed old growth, we determined an equivalent “big” size threshold for each indicator and calculated the area of old growth above the size threshold. Stand volume, tree density, basal area, and diameter estimates performed poorly; we selected tree height and two measures of site productivity for further analysis. Estimated tree height best indicated the current old growth size, followed by inventory-based site index and finally ecosystem-based site index. The calibrated indicators agreed that very little remaining old growth supports large trees (1.5–3.3% for the biggest trees; 6–13% including medium-sized trees that represent the largest growing trees in lower productivity interior ecosystems). Tree height cannot be used to compare the remaining area of big-treed old growth to the area expected naturally, an important input for ecological risk assessment and conservation planning because height data are lost from the inventory after harvest. The two calibrated site productivity indicators agreed that the amount remaining is less than 30% of the expected historical amount, posing a high risk to biodiversity and resilience. We recommend using estimated height to identify the biggest remaining old-growth stands for regional planning and calibrated inventory-based site index for risk assessment until a detailed ecosystem mapping has been verified to represent old-growth variability. To reduce uncertainty, we suggest that planning groups compare several indicators and analysis approaches, adjusted to ensure equivalence, and use precaution to avoid any unknowingly increasing risks.

Floristički diverzitet veštački podignutih sastojina različitih vrsta četinara na području Kosmaja (Srbija)

One of the causes of decrease of species diversity of forest ecosystems could be inadequate selection of tree species for afforestation and ameliorations. It is known that by establishing new forest ecosystem habitat conditions change, and thus, edaphic and hydrological conditions and light regime also change, which directly or indirectly reflects on plant species. The research included four artificially established stands (pure or mixed) in the area of Kosmaj, where various coniferous species were introduced in the process of substitution of autochthonous forests of Hungarian oak and Turkey oak. The largest total number of plant species was recorded in artificially established stand of common spruce, Atlas cedar, and Douglas-fir (41). The highest Shannon-Wiener diversity index was recorded in stand of Douglas-fir (3.22), and the lowest in pine stands (2.95-2.97). It was determined by cluster analysis that stand of Austrian pine and stand of Austrian pine and Scots pine have the largest degree of mutual floristic similarity.

Contrasting Responses of Alien and Ancient Forest Indicator Plant Species to Fragmentation Process in the Temperate Lowland Forests.

Fragmentation is one of the major threats to biodiversity. In a fragmented landscape, forest specialists are losing suitable forest habitats with specific site and microclimate conditions, which results in their local extinction. Conversely, the invasion of alien species is facilitated by open forest areas and increased boundaries between forest fragments and adjacent land. We studied the effect of fragmentation in terms of fragment size impact on overall plant species richness and on selected ecologically important groups' richness, composition, and diversity. We surveyed vegetation in the interior of 47 fragments of various sizes and one unfragmented reference forest. Our results reveal that the effect of fragmentation is complex and differs for studied plant groups. Decreasing fragment size negatively affects the overall plant richness and richness of native and ancient forest indicator plants as well as their diversity, while the effect is positive for alien plants. The highest proportion of ancient forest indicator plant species and the lowest proportion of alien plants in the unfragmented forest underline the great conservation value of forest fragments. At the same time, our results reveal that large and diverse forest ecosystems are susceptible to biological invasions as well.

Rapid assessment of feeding traces enables detection of drivers of saproxylic insects across spatial scales

Knowledge of habitat requirements of saproxylic insects and their response to habitat changes is critical for assessing the ecological impacts of forest management. Several studies have demonstrated a positive relationship of tree-species richness, deadwood volume, or structural diversity with saproxylic species diversity, while the relationship with the abundance of potential pest species have often been negative. A better understanding of which factors drive saproxylic insects’ occurrence is therefore essential for deriving urgently needed thresholds for key habitat conditions. We tested a rapid assessment method applicable at large scale based on recorded feeding galleries and boreholes assessed during the Austrian National Forest Inventory to investigate the drivers and habitat thresholds of different saproxylic insect families; i.e. Buprestidae, Cerambycidae, Curculionidae, Siricidae, at multiple spatial scales; i.e. at the object, forest stand and landscape level. We modelled the relative abundance of all insects and these families considering nineteen explanatory variables using ordinal logistic regression models. Key habitat characteristics were identified using recursive partitioning. Our results revealed complex interactions among influencing factors at different spatial scales. We showed that deadwood volume was of surprisingly little importance. Instead, individual tree characteristics were of major importance, demonstrating the value of resource quality and variability. The abundance of all saproxylic insect families increased with advancing decomposition, on trees taller than 18 m, and above a living stand volume of 41 m3ha−1. Aiming to guide forest management, not only forest type-specific, but tree species-specific deadwood management is needed, taking into account site-specific conditions, including temperature and precipitation. For assessing temporal trends in insect colonization and habitat dynamics as well as the effects of forest management, we propose a continuous monitoring of insect traces, including living but weakened trees. This will allow for further thresholds that are urgently needed for maintaining biological diversity in forest ecosystems in the face of climate change.

Assessing tree species diversity in forest ecosystems: A new approach

The significance of biodiversity research is to understand the structure and function of the community, and then to protect and monitor the community. The metric of biodiversity is the base of biodiversity conservation. Species richness and evenness are the most common descriptors of biodiversity. Whether it is diversity information measure, probability measure or geometric measure, they all express the combination of species richness and evenness in different ways. This study presents a new biologically meaningful measure of species diversity, which evaluates species richness and evenness independently, designated as DRE. The novelty of our method is to use “absolute discrepancy” to express the dissimilarity between the observed community and the uniform distribution community with the same species composition and same abundance of each species, and then measure the species evenness. The logarithmic transformation of the species number is used to measure species richness with values ranging between 0 and 1. We test the performance of this measure using simulated data and observations of natural and planted forests in different climatic zones. The results showed that the new diversity index (DRE) has superior statistical qualities compared with the traditional indices. Especially, in extremely uneven communities, the new measure describes the causes of diversity changes than the traditional DRE. In addition, DRE is more sensitive to the abundance changes of rare species in the simulated community, and the interpretation of the results is more intuitive and meaningful. It is an improved method to evaluate the species diversity of any ecosystem.

Forest management practices in Spain: Understanding past trends to better face future challenges

Because forests provide a myriad of essential services to society, sustainable forest management that considers and promotes the multifunctional role of forests is of key importance. Understanding how forests have been and are being managed is essential to learn how current forest landscapes have been shaped and how management could be improved to better address all societal needs. Spain makes for an interesting case study due to its dramatic expansion in forest cover over the last 150 years following ambitious national reforestation and afforestation initiatives, as well as for its diversity of forest ecosystems and management approaches. However, a national-level assessment of such a development is currently missing. Therefore, our objective was to document and analyse the development of forest management practices in Spain since the mid-20th century. We developed narratives to describe the trends in 11 indicators of forest management decision-making and practices. Results show that while some decisions have evolved towards promoting multifunctionality (e.g., soil cultivation), others have intensified to maximize production at the expense of other ecosystem services (e.g., naturalness of tree species) and others have not changed much during the past 80 years (e.g., type of regeneration). The analysis also showed that some of the indicators have been conditioned by technological innovations (e.g., machine operation) and by the development of certain policies and legislation (e.g., the application of chemical agents). Based on these trends, we identified the main challenges that forest management in general, and in Spain in particular, may face as well as some decisions that may have to be reconsidered (cutting regime, tree maturity, naturalness of tree species) if the country wants to transition towards alternative silvicultural approaches that promote multifunctionality. In addition, a transition towards mixed-species, uneven-aged forests alongside with genetic improvement of tree species would also facilitate rising to one of the main challenges that forest management faces: to develop a climate-smart forestry that contributes to the mitigation of and adaptation to global change.

Soil fungal communities show more specificity than bacteria for plant species composition in a temperate forest in China

BackgroundSoil microbiome is an important part of the forest ecosystem and participates in forest ecological restoration and reconstruction. Niche differentiation with respect to resources is a prominent hypothesis to account for the maintenance of species diversity in forest ecosystems. Resource-based niche differentiation has driven ecological specialization. Plants influence soil microbial diversity and distribution by affecting the soil environment. However, with the change in plant population type, whether the distribution of soil microbes is random or follows an ecologically specialized manner remains to be further studied. We characterized the soil microbiome (bacteria and fungi) in different plant populations to assess the effects of phytophysiognomy on the distribution patterns of soil microbial communities in a temperate forest in China.ResultsOur results showed that the distribution of most soil microbes in different types of plant populations is not random but specialized in these temperate forests. The distribution patterns of bacteria and fungi were related to the composition of plant communities. Fungal species (32%) showed higher specialization than bacterial species (15%) for different types of plant populations. Light was the main driving factor of the fungal community, and soil physicochemical factors were the main driving factor of the bacterial community.ConclusionThese findings suggest that ecological specialization is important in maintaining local diversity in soil microbial communities in this forest. Fungi are more specialized than bacteria in the face of changes in plant population types. Changes in plant community composition could have important effects on soil microbial communities by potentially influencing the stability and stress resistance of forest ecosystems.