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Context: Forest microclimate influences biodiversity and plays a crucial role in regulating forest ecosystem functions. It is modified by forest management as a result of changes in forest structure due to tree harvesting and thinning. Objectives: Here, we investigate the impacts of even-aged and uneven-aged forest management on stand- and landscape-level heterogeneity of forest microclimates, in comparison with unmanaged, old-growth European beech forest. Methods: We combined stand structural and topographical indices derived from airborne laser scanning with climate observations from 23 meteorological stations at permanent forest plots within the Hainich region, Germany. Based on a multiple linear regression model, we spatially interpolated the diurnal temperature range (DTR) as an indicator of forest microclimate across a 4338 ha section of the forest with 50 m spatial resolution. Microclimate heterogeneity was measured as α-, β-, and γ-diversity of thermal niches (i.e. DTR classes). Results: Even-aged forests showed a higher γ-diversity of microclimates than uneven-aged and unmanaged forests. This was mainly due to a higher β-diversity resulting from the spatial coexistence of different forest developmental stages within the landscape. The greater structural complexity at the stand-level in uneven-aged stands did not increase α-diversity of microclimates. Predicted DTR was significantly lower and spatially more homogenous in unmanaged forest compared to both types of managed forest. Conclusion: If forest management aims at creating a wide range of habitats with different microclimates within a landscape, spatially co-existing types of differently managed and unmanaged forests should be considered, instead of focusing on a specific type of management, or setting aside forest reserves only. [ABSTRACT FROM AUTHOR]

Most forests in Central Europe are subject to human management, especially timber harvesting, which alters soil conditions by creating gaps in the forest canopy and reduces the availability of deadwood. However, consequences of these management practices, in particular the combined effect of gap formation and deadwood removal, have been largely neglected. Here, we investigated the abundance, diversity and community composition of oribatid mites (Acari: Oribatida) in forests where deadwood availability and gap formation were manipulated in a full factorial design (Control, Gap, Deadwood, Gap + Deadwood). Forest gaps of about 30 m in diameter were established by felling trees, which were subsequently removed (Gap) or left on site as deadwood (Gap + Deadwood). Nearby forest sites without gaps were enriched with the equal amount of felled trees (Deadwood) or left untreated (Control). Experimental treatments were established at 29 forest sites including deciduous and coniferous stands in three regions of Germany, i.e. the Swabian Alb, Hanich-Dün and Schorfheide-Chorin in the south, center and north, respectively. One year after establishment of the treatments, we sampled 10,777 individuals and 104 species of oribatid mites. Deadwood addition significantly increased the density of oribatid mites in the Hainich-Dün from 24,036 to 46,658 ind. m-². Specifically, species of Oppiidae with relatively short life cycles and high reproductive output benefited from the additional deadwood supply, resulting in shifts in community compositions between treatments with and without deadwood. By contrast, mean oribatid mite density decreased from an average of 64,083 in controls to 36,621 ind. m-² in forest gaps of the Schorfheide-Chorin and the Swabian Alb. Presumably, adverse abiotic conditions, mainly amplified drought, induced higher mortality rates in these regions. Overall, deadwood addition and forest gap formation had strong effects on oribatid mite communities, although the magnitude of each effect was similar between forest types and largely determined by regional context. This emphasizes that the effects of forest management practices on oribatid mite communities cannot be generalized across regional scales, suggesting that management plans should carefully consider regional differences. • Large logs of deadwood increase the density of oribatid mites in forest soil. • Forest gaps reduce the density and species number of oribatid mites. • Effects of deadwood addition and forest gap formation differ between regions. • Deadwood addition to forest gaps does not mitigate detrimental effects of gaps. [ABSTRACT FROM AUTHOR]

Biodiversity loss, as often found in intensively managed agricultural landscapes, correlates with reduced ecosystem functioning, for example, pollination by insects, and with altered plant composition, diversity, and abundance. But how does this change in floral resource diversity and composition relate to occurrence and resource use patterns of trap‐nesting solitary bees? To better understand the impact of land‐use intensification on communities of trap‐nesting solitary bees in managed grasslands, we investigated their pollen foraging, reproductive fitness, and the nutritional quality of larval food along a land‐use intensity gradient in Germany. We found bee species diversity to decrease with increasing land‐use intensity irrespective of region‐specific community compositions and interaction networks. Land use also strongly affected the diversity and composition of pollen collected by bees. Lack of suitable pollen sources likely explains the absence of several bee species at sites of high land‐use intensity. The only species present throughout, Osmia bicornis (red mason bee), foraged on largely different pollen sources across sites. In doing so, it maintained a relatively stable, albeit variable nutritional quality of larval diets (i.e., protein to lipid (P:L) ratio). The observed changes in bee–plant pollen interaction patterns indicate that only the flexible generalists, such as O. bicornis, may be able to compensate the strong alterations in floral resource landscapes and to obtain food of sufficient quality through readily shifting to alternative plant sources. In contrast, other, less flexible, bee species disappear. [ABSTRACT FROM AUTHOR]

Evidence from experimental and established grasslands indicates that plant biodiversity can modify the water cycle. One suspected mechanism behind this is a higher infiltration capacity (νB) and hydraulic conductivity (K) of the soil on species‐rich grasslands. However, in established and agriculturally managed grasslands, biodiversity effects cannot be studied independent of land‐use effects. Therefore, we investigated in established grassland systems how land‐use intensity and associated biodiversity of plants and soil animals affect νB and K at and close to saturation. On 50 grassland plots along a land‐use intensity gradient in the Biodiversity Exploratory Schwäbische Alb, Germany, we measured νB with a hood infiltrometer at several matrix potentials and calculated the saturated and unsaturated K. We statistically analysed the relationship between νB or K and land‐use information (e.g., fertilising intensity), abiotic (e.g., soil texture) and biotic data (e.g., plant species richness, earthworm abundance). Land‐use intensity decreased and plant species richness increased νB and K, while the direction of the effects of soil animals was inconsistent. The effect of land‐use intensity on νB and K was mainly attributable to its negative effect on plant species richness. Our results demonstrate that plant species richness was a better predictor of νB and K at and close to saturation than land‐use intensity or soil physical properties in the established grassland systems of the Schwäbische Alb. [ABSTRACT FROM AUTHOR]

Intensive land use has been shown to alter the composition and functioning of soil communities. Due to their low dispersal ability, oribatid mites are particularly vulnerable to land-use intensification and species which are not adjusted to management-related disturbances become less abundant. We investigated how different land-use parameters in forests and grasslands affect oribatid mite diversity and abundance, with a focus on: (1) species-level impacts, by classifying species as increasing ('winners') or decreasing ('losers') in abundance with higher land-use intensity, and (2) reproductive impact, by investigating whether sexual and parthenogenetic species react differently. We collected 32,542 adult oribatid mites in 60 forests and grasslands of known land-use intensity in two regions of Germany. Diversity and total abundance as well as the proportion of sexual species were higher in forests than in grasslands. Diversity declined with higher land-use intensity in forests, but increased with higher mowing and fertilization in grasslands. Depending on land-use parameter and region, abundance either declined or remained unaffected by increasing intensity. Gravidity was higher in sexual than in parthenogenetic species and sexuals had 1.6× more eggs per gravid female. Proportions of sexual species and gravid females decreased with land-use intensity in forests, but increased with mowing in grasslands. At the species level, 75% of sexuals and 87.5% of parthenogens were 'losers' of higher percentages of dead wood originating from management-related disturbances. Across land-use parameters and habitats, a similar proportion of sexual and parthenogenetic oribatid mite species were 'losers' of high land-use intensity. However, 'winner' species were more common among sexuals. [ABSTRACT FROM AUTHOR]

Soil P pools are strongly driven by microbial activities, and vice versa, P pools shape bacterial communities and their functional potential. Biological soil crusts (biocrusts) represent a microbial hotspot for nutrient turnover. We compared biocrusts and bulk soil samples from different temperate beech (Fagus sylvatica L.) forests representing a gradient in soil texture, nutrient concentrations, and pH values at biocrust peak biomass. We measured the total and plant-available P and N concentrations and assessed the bacterial potential to mineralize (phoD, phnX), solubilize (gcd), and take up P (pstS and pitA) and mineralize (chiA, apr) and fix N (nifH) by quantifying the respective marker genes (qPCR). We found an increase of absolute and relative bacterial abundance involved in P turnover in biocrusts, but the strategy to acquire P differed between the regions as bacteria harboring the starvation-induced pstS gene were most abundant where labile P was lowest. In contrast, the region with lowest total P concentrations has a higher potential to utilize more stable phosphonates. N mineralization was strongly correlated to P turnover at regions with increased labile N and P concentrations. Interestingly, the potential to fix N was highest in the bulk soil where total P concentrations were highest. Even though the correlation of N and P turnover is strongest if their ratio is low, the acquisition strategy strongly depends on soil properties. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A large-scale study combining pheromone trapping and experimental logs. • Management decreases abundance and attack probability of native ambrosia beetles. • The abundance of invasive X. germanus may be increased by management. • Pest control of native T. domesticum is less effective at high management intensities. • Substrate availability, microclimate and antagonists drive ambrosia beetle abundance. Abstract Land-use intensification has been shown to negatively affect biodiversity and ecosystem functioning. Because higher trophic levels are expected to suffer most strongly from intensification, negative consequences for ecosystem services, such as biological pest control by natural enemies, are likely. In European beech forests ambrosia beetles are common secondary pests of freshly cut wood and stored timber, but they may also infest living trees that are highly stressed. We examined whether forest management intensity, ranging from unmanaged beech forests to non-natural conifer plantations, affects the abundance, attack rate, and breeding success of ambrosia beetles across three regions of Germany. We applied pheromone trapping to estimate the abundance of ambrosia beetles and exposed experimental beech logs to measure infestation rates and breeding success. In general, we found decreasing abundance and attack probability by ambrosia beetles with increasing management intensity, which is most likely related to the availability of suitable breeding substrate. However, the abundance of the invasive species Xylosandrus germanus increased with increasing management intensity in one region, where high management intensity was represented by pine forests; the drier and warmer conditions in this forest type most likely increased population densities. Breeding success of Trypodendron domesticum increased with increasing management intensity, suggesting less effective pest control by natural antagonists, in particular by specialised parasitoids, at high management intensities. We conclude that the availability of breeding substrate, in combination with microclimate and antagonist effectiveness, shape ambrosia beetle populations in Central European forests. Forest management strategies should thus reduce the availability of breeding substrate in production forests, in particular where microclimatic conditions are favourable for beetle reproduction (i.e. warm, moist). Moreover, unmanaged forest patches should be maintained to promote parasitoid abundance and thus to mitigate negative effects of climate change, such as increasing drought stress of trees. [ABSTRACT FROM AUTHOR]

Questions: To what extent is trait variation in grasses and forbs driven by land-use intensity, climate, soil conditions and plant diversity of the local neighbourhood? Do grass and forb species differ in the degree of intraspecific trait variation? Location: Managed grasslands in three regions of Germany. Methods: Using a phytometer approach,we raised 20 common European grassland species (ten forbs and ten grasses) and planted them into 54 plots of different land-use types (pasture, meadow, mown pasture). After 1 yr in the field, we measured above- and below-ground plant functional traits. Linear mixed effects models (LMEM) were used to identify the most powerful predictors for every trait. Variation partitioning was applied to assess the amount of inter- and intraspecific trait variation in grasses and forbs explained by environmental conditions (land-use intensity, climate and soil conditions) and plant species diversity of the local neighbourhood. Results: For 12 out of the 14 traits studied, either land-use intensity or local neighbourhood diversity were predictors in the best LMEM. Land-use intensity had considerably stronger effects than neighbourhood diversity. Root dry matter content and root phosphorus concentration of forbs were more affected by land-use intensity than those of grasses. For almost all traits, intraspecific trait variation of grasses was much higher than that of forbs, while traits of forbs varied more among species. Overall, inter- and intraspecific variation was of the same magnitude. Conclusion: The similar magnitude of intra- and interspecific trait variation suggests that both sources should be considered in grassland studies at a scale similar to that of our study. The high amount of intraspecific trait variation that was explained by environmental factors and local neighbourhood diversity clearly demonstrates the high potential of species to adjust to local conditions, which would be ignored when only considering species mean trait values. [ABSTRACT FROM AUTHOR]

The effects of management on insect communities have been studied in several forest ecosystems, although the consequences for single potential pests are only known for a few species. The present study investigated whether forest management affects the infestation of European beech trees by the beech scale Cryptococcus fagisuga., We assessed the densities of C. fagisuga on a total of 520 trees ( Fagus sylvatica) at 104 forest sites, representing three main types of beech forest management intensity across three regions in Germany., The infestation rates on beech trees were 16% in the South- West, 20% in the Centre and 35% in the North- East of Germany, although the rates per plot did not differ significantly among regions. No significant differences between unmanaged beech, managed even-aged beech and managed uneven-aged beech forests were found because of high variability in beech scale infestation observed among forest sites and within forest management types. Highest infestation rates occurred on widely dispersed mature trees within thickets with shelterwood stage and lowest infestation rates occurred on young beech trees in the thicket stage., The results of the present study suggest that the infestation rates of C. fagisuga on beech depend on tree age and canopy openness rather than on management intensity. [ABSTRACT FROM AUTHOR]

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Abstract: Understanding changes in biodiversity in agricultural landscapes in relation to land-use type and intensity is a major issue in current ecological research. In this context nutrient enrichment has been identified as a key mechanism inducing species loss in Central European grassland ecosystems. At the same time, insights into the linkage between agricultural land use and plant nutrient status are largely missing. So far, studies on the relationship between chemical composition of plant community biomass and biodiversity have mainly been restricted to wetlands and all these studies neglected the effects of land use. Therefore, we analyzed aboveground biomass of 145 grassland plots covering a gradient of land-use intensities in three regions across Germany. In particular, we explored relationships between vascular plant species richness and nutrient concentrations as well as fibre contents (neutral and acid detergent fibre and lignin) in the aboveground community biomass. We found the concentrations of several nutrients in the biomass to be closely linked to plant species richness and land use. Whereas phosphorus concentrations increased with land-use intensity and decreased with plant species richness, nitrogen and potassium concentrations showed less clear patterns. Fibre fractions were negatively related to nutrient concentrations in biomass, but hardly to land-use measures and species richness. Only high lignin contents were positively associated with species richness of grasslands. The N:P ratio was strongly positively related to species richness and even more so to the number of endangered plant species, indicating a higher persistence of endangered species under P (co-)limited conditions. Therefore, we stress the importance of low P supply for species-rich grasslands and suggest the N:P ratio in community biomass to be a useful proxy of the conservation value of agriculturally used grasslands. [Copyright &y& Elsevier]

• Estimation-based structural Index of biodiversity potential (IBP) is tested by comparing it with conventional species monitoring data. • IBP is positively correlated with species richness of birds, fungi, true bugs, lichens, and moths. • Easy and time-efficient IBP serves as proxy for a potential biodiversity. Effects of forest management on forest biodiversity have received increasing attention in both research and forestry practice. Despite advances in technology, monitoring of biodiversity remains time and cost-intensive and requires specific taxonomic expertise. In forest management, however, there is increasing interest and need to integrate biodiversity monitoring into forest inventories efficiently to estimate the potential effects of forest management on biodiversity. Forest management systems can differ greatly depending on management goals and the intensity and frequency of the applied silvicultural interventions. To identify management effects on biodiversity, an estimation of biodiversity using forest structural attributes may be a reasonable approach. Forest structure can – compared to conventional species-based monitoring - easily be captured during forest inventories and does not require specific taxonomic expertise. The IBP (Index of Biodiversity Potential) is a composite index aiming to provide practitioners with an efficient tool for estimating biodiversity at the local level. We recorded the IBP on 147 plots in three regions of Germany, where detailed biodiversity monitoring had been conducted. This study quantified the relationship between changes in the IBP scores and changes in species richness for 13 taxonomic groups. To determine this, we analyzed estimated relationships between the IBP and species richness using a count regression model. We found positive estimated relationships with species richness of birds, fungi, true bugs, lichens, and moths in at least 3 of 5 examined forest types. However, for spiders, bats, carabids, necrophagous and saproxylic beetles, either no relationship with the IBP or estimated relationships with only one forest type were found. Changes in scores for the IBP's factors number of vertical layers, large living trees, tree-related microhabitats, and proportion of gaps correlated with changes in the measured species richness in many cases. Even though the IBP is generally not adequate to predict actual presence or precise number of species, it can be utilized to depict a forest stand's potential in terms of species richness. Due to its easy and time-efficient application, it could be a useful proxy used in combination with species-based monitoring approaches. [ABSTRACT FROM AUTHOR]

The current biodiversity decline through anthropogenic land-use not only involves local species losses, but also homogenization of communities, with a few generalist species benefitting most from human activities. Most studies assessed community heterogeneity (β-diversity) on larger scales by comparing different sites, but little is known about impacts on β-diversity within each site, which is relevant for understanding variation in the level of α-diversity, the small-scale distribution of species and associated habitat heterogeneity. To obtain our dataset with 36,899 individuals out of 117 different plant- and leafhopper (Auchenorrhyncha) species, we sampled communities of 140 managed grassland sites across Germany by quantitative vacuum suction of five 1 m 2 plots on each site. Sites differed in land-use intensity as characterized by intensity of fertilization, mowing and grazing. Our results demonstrate a significant within-site homogenization of plant- and leafhopper communities with increasing land-use intensity. Correspondingly, density (- 78%) and γ-diversity (- 35%) declined, particularly with fertilization and mowing intensity. More than 34% of plant- and leafhopper species were significant losers and only 6% were winners of high land-use intensity, with abundant and widespread species being less affected. Increasing land-use intensity adversely affected dietary specialists and promoted generalist species. Our study emphasizes considerable, multifaceted effects of land-use intensification on species loss, with a few dominant generalists winning, and an emerging trend towards more homogenized assemblages. By demonstrating homogenization for the first time within sites, our study highlights that anthropogenic influences on biodiversity even occur on small scales.

Although temporal heterogeneity is a well-accepted driver of biodiversity, effects of interannual variation in land-use intensity (LUI) have not been addressed yet. Additionally, responses to land use can differ greatly among different organisms; therefore, overall effects of land-use on total local biodiversity are hardly known. To test for effects of LUI (quantified as the combined intensity of fertilization, grazing, and mowing) and interannual variation in LUI (SD in LUI across time), we introduce a unique measure of whole-ecosystem biodiversity, multidiversity. This synthesizes individual diversity measures across up to 49 taxonomic groups of plants, animals, fungi, and bacteria from 150 grasslands. Multidiversity declined with increasing LUI among grasslands, particularly for rarer species and aboveground organisms, whereas common species and belowground groups were less sensitive. However, a high level of interannual variation in LUI increased overall multidiversity at low LUI and was even more beneficial for rarer species because it slowed the rate at which the multidiversity of rare species declined with increasing LUI. In more intensively managed grasslands, the diversity of rarer species was, on average, 18% of the maximum diversity across all grasslands when LUI was static over time but increased to 31% of the maximum when LUI changed maximally over time. In addition to decreasing overall LUI, we suggest varying LUI across years as a complementary strategy to promote biodiversity conservation.