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Reversing the decline of biodiversity in European agricultural landscapes is urgent. We suggest eight measures addressing politics, economics, and civil society to instigate transformative changes in agricultural landscapes. We emphasize the need for a well-informed society and political measures promoting sustainable farming by combining food production and biodiversity conservation [ABSTRACT FROM AUTHOR]

Tree growth is the most important factor in determining the carbon sequestration processes of forest ecosystems. However, the growth phenology (seasonal growth pattern) and responses of tree growth to climatic variables vary considerably among different species, especially between deciduous and evergreen species. Thus, it is crucial to explore the seasonal growth patterns of different tree species in relation to climate to better understand the responses of tree physiology to climate changes, especially in mixed-species forest stands. In this study, we monitored the daily basal area increments of 220 individuals belonging to 15 common broadleaved tree species, nine deciduous and six evergreen species, in mixed-species experimental stands in subtropical China and analysed the relationships between radial stem growth and seasonal climate at a high-temporal resolution. We fitted daily increments of stem diameters with four frequently used nonlinear models and chose the best model for each species. The results showed that the evergreen trees grew faster than the deciduous trees, both annually and within the growing season. The tested nonlinear models (Korf, Weibull, logistic and Gompertz) produced good fits for the growth patterns of all species. Overall, the evergreen species began stem growth earlier and finished later during the growing season than that of the deciduous species. Within the growing season, the radial growth of trees in mixed stands containing both types of species was strongly positively correlated with humidity. In spring, increases in both temperature and moisture increased the daily relative basal area increment of all species. Maximum growth rates occurred when the soil water content reached its highest level and gradually decreased when the soil water content decreased. In summer, high temperatures combined with low amounts of precipitation led to heat-induced summer drought, to which the evergreen trees appeared to be more tolerant than the deciduous trees, which was reflected in the reduced stem growth of the latter. These results indicate the different climate-dependent seasonal growth strategies of evergreen and deciduous trees related to the trade-off described by the leaf economics spectrum, i.e., short-lived leaves with higher assimilation rates in deciduous and longer-lived leaves with a greater drought tolerance in evergreen species. [ABSTRACT FROM AUTHOR]

In plant ecology, community-weighted trait means are often used as predictors for ecosystem functions. More recently, also within-species trait variation has been confirmed to contribute to ecosystem functioning. We here go even further and assess within-individual trait variation, assuming that every leaf in a plant individually adjusts to its micro-environment. Using forest plots varying in tree species richness (Sardinilla experiment, Panama), we analysed how leaf traits within individual trees vary along the vertical crown gradient. Furthermore, we tested whether niche partitioning in mixed stands results in a decrease of within-species leaf trait variation and whether niche partitioning can be also observed at the level of individual trees. We focused on leaf traits that describe the growth strategy along the conservative-acquisitive spectrum of growth. We found a decrease in within-species variation of specific leaf area (SLA) with increasing neighbourhood species richness. Both sampling height and local neighbourhood richness contributed to explaining within-species leaf trait variation, which however, varied in importance among different species and traits. With increasing sampling height, leaf dry matter content (LDMC), carbon to nitrogen ratio and lignin content increased, while leaf nitrogen concentration (leaf N), SLA, cellulose and hemicellulose decreased. Variation in leaf N decreased with increasing neighbourhood species richness, while the magnitude of within-individual variation of most traits was unaffected by neighbourhood species richness. Our results suggest an increased niche partitioning with increasing species richness both in a plant community and at the level of individual plants. Our findings highlight the importance of including within-individual trait variation to understand biodiversity-ecosystem functioning relationships. [ABSTRACT FROM AUTHOR]

• Research on tree diversity and antagonists often neglects plant complementarity. • We studied species richness/mycorrhizal type effects on leaf herbivory/pathogens. • Mycorrhizal type had different effects on herbivory and pathogen infestation. • Elemental not metabolite concentrations determined leaf damage.ld. Research aimed at understanding the mechanisms underlying the relationship between tree diversity and antagonist infestation is often neglecting resource-use complementarity among plant species. We investigated the effects of tree species identity, species richness, and mycorrhizal type on leaf herbivory and pathogen infestation. We used a tree sapling experiment manipulating the two most common mycorrhizal types, arbuscular mycorrhiza and ectomycorrhiza, via respective tree species in monocultures and two-species mixtures. We visually assessed leaf herbivory and pathogen infestation rates, and measured concentrations of a suite of plant metabolites (amino acids, sugars, and phenolics), leaf elemental concentrations (carbon, nitrogen, and phosphorus), and tree biomass. Tree species and mycorrhizal richness had no significant effect on herbivory and pathogen infestation, whereas species identity and mycorrhizal type had. Damage rates were higher in arbuscular mycorrhizal (AM) than in ectomycorrhizal (EM) trees. Our structural equation model (SEM) indicated that elemental, but not metabolite concentrations, determined herbivory and pathogen infestation, suggesting that the investigated chemical defence strategies may not have been involved in the effects found in our study with tree saplings. Other chemical and physical defence strategies as well as species identity as its determinant may have played a more crucial role in the studied saplings. Furthermore, the SEM indicated a direct positive effect of AM trees on herbivory rates, suggesting that other dominant mechanisms, not considered here, were involved as well. We found differences in the attribution of elemental concentrations between the two rates. This points to the fact that herbivory and pathogen infestation are driven by distinct mechanisms. Our study highlights the importance of biotic contexts for understanding the mechanisms underlying the effects of biodiversity on tree-antagonist interactions. [ABSTRACT FROM AUTHOR]

In plant ecology, community-weighted trait means are often used as predictors for ecosystem functions. More recently, also within-species trait variation has been confirmed to contribute to ecosystem functioning. We here go even further and assess within-individual trait variation, assuming that every leaf in a plant individually adjusts to its micro-environment. Using forest plots varying in tree species richness (Sardinilla experiment, Panama), we analysed how leaf traits within individual trees vary along the vertical crown gradient. Furthermore, we tested whether niche partitioning in mixed stands results in a decrease of within-species leaf trait variation and whether niche partitioning can be also observed at the level of individual trees. We focused on leaf traits that describe the growth strategy along the conservative-acquisitive spectrum of growth. We found a decrease in within-species variation of specific leaf area (SLA) with increasing neighbourhood species richness. Both sampling height and local neighbourhood richness contributed to explaining within-species leaf trait variation, which however, varied in importance among different species and traits. With increasing sampling height, leaf dry matter content (LDMC), carbon to nitrogen ratio and lignin content increased, while leaf nitrogen concentration (leaf N), SLA, cellulose and hemicellulose decreased. Variation in leaf N decreased with increasing neighbourhood species richness, while the magnitude of within-individual variation of most traits was unaffected by neighbourhood species richness. Our results suggest an increased niche partitioning with increasing species richness both in a plant community and at the level of individual plants. Our findings highlight the importance of including within-individual trait variation to understand biodiversity-ecosystem functioning relationships. [ABSTRACT FROM AUTHOR]

Given the key role of belowground biota on forest ecosystem functioning, it is important to identify the factors that influence their abundance and composition. However, the understanding of the ecological linkage between tree diversity and belowground biota is still insufficient. Here we investigated the influence of tree diversity (richness, True Shannon diversity index, functional diversity) and identity (proportion of evergreen leaf litter and leaf litter quality) on earthworm species richness and biomass at a continental and regional scale, using data from a Europe-wide forest research platform (FunDivEUROPE) spanning six major forest types. We found a marked tree identity effect at the continental scale, with proportion of evergreen leaf litter negatively affecting total earthworm biomass and species richness, as well as their biomass per functional group. Furthermore, there were clear litter quality effects with a latitudinal variation in trait-specific responses. In north and central Europe, earthworm biomass and species richness clearly increased with increasing litter nutrient concentrations (decreasing C:N ratio and increasing calcium concentration), whereas this influence of litter nutrients was absent or even reversed in southern Europe. In addition, although earthworms were unaffected by the number of tree species, tree diversity positively affected earthworm biomass at the continental scale through functional diversity of the leaf litter. By focusing on tree leaf litter traits, this study advanced our understanding of the mechanisms driving tree identity effects and supported previous findings that litter quality, as a proxy of tree identity, was a stronger driver of earthworm species richness and biomass than tree diversity. [ABSTRACT FROM AUTHOR]

Fine roots (diameter ≤ 2 mm) contribute significantly to the forest carbon cycle and are essential for resource acquisition from the soil. We conducted a study to assess the relationships between tree and ground vegetation fine root biomass and tree species diversity (monocultures compared to 2–5 species mixtures), conifer proportion and other site factors (stand basal area, soil carbon stocks and C:N ratio) in the six major European forest types, boreal forest in Finland, temperate forests in Poland, Germany and Romania, thermophilous deciduous forests in Italy, and Mediterranean forests in Spain. We sampled the fine roots of trees and ground vegetation to the depth of 20 cm in the mineral soil and allocated the fine root biomass to individual tree species using near-infrared reflectance spectroscopy (NIRS). We did not find any general positive effects of tree species diversity on the fine root biomass of trees or ground vegetation across the forest types and tree species combinations. However, our results suggest that tree fine root biomass increases with tree species diversity in pure broadleaf forests, but not in pure conifer forests. Species diversity explained 7% of the variation in tree fine root biomass in the broadleaf stands. The narrow tree species diversity gradient (1–2 species) in the conifer forests compared to the broadleaf forests (1−4) may have decreased the probability of conifer species combinations with below-ground functional traits conducive to over-yielding. Some evidence of diversity-mediated changes in the vertical rooting patterns of broadleaf trees and ground vegetation were found within the entire organic and 0–20 cm mineral soil layer although the weighted mean depth of fine root biomass was not affected. Negative diversity effects were found in the organic layer and positive diversity effects in the 0–10 cm mineral soil layer for broadleaf tree fine root biomass. Diversity effects were negative for ground vegetation fine root biomass in the 0–10 cm mineral soil layer. There was a general positive effect of conifer proportion on total fine root biomass in the organic layer, but not in the mineral soil layers. In general conifer proportion and site factors explained more of the variation in tree fine root biomass than tree species diversity. More research covering the annual variation in fine root biomass and deeper soil layers is needed before recommending managing species-rich forest for increasing below-ground biomass and carbon pools. [ABSTRACT FROM AUTHOR]

Future climate projections for Central Europe indicate a decrease in summer precipitation which might range between 15% and 50%, and equally important, changes in the climate variability, resulting in consecutive years with drought periods. With respect to Central European forests, we asked to which degree realistic drought conditions are tolerated by the recruits of the dominant tree species Fagus sylvatica L . , and how the effects depend on biotic interactions. To test the combined effects of drought, competition and provenance of F. sylvatica recruits we set up a rain shelter experiment at three sites in different regions of Germany. Transposable roof panels allowed a flexible precipitation reduction between 10% and 70% corresponding with a return period of 40 years. We planted F. sylvatica saplings of three provenances, exposed them to drought and competition. We tested if understorey herbaceous competitors have a negative impact on F. sylvatica saplings, and thus, exacerbate drought effects and that F. sylvatica provenances from drier regions are adapted to drought conditions and cope better with drought conditions. Six months after the drought treatment started, we encountered significant drought effects, seen in a reduced leaf stomatal conductance, although there was not yet a response in growth rates. Overall, the site had the greatest impact on phytometer performance, while we found no indication of adaptation to drought of the different provenances. Furthermore, drought effects increased in interaction with site effects, being highest at the driest site. At the driest site, leaf stomatal conductance decreased in the presence of competition but increased in the control subplots, while the site of intermediate moisture conditions showed the opposite pattern and the wettest site displayed no differences. Our results highlight the fact that biotic interactions can mitigate or exacerbate drought effects, depending on regional site conditions. [ABSTRACT FROM AUTHOR]

Reforestation and afforestation often takes place in the form of monocultures. These have increasingly come under criticism due to their greater susceptibility to adverse environmental conditions and pathogens and because of the negative long-term impacts they have on soil fertility. Moreover, reservations have frequently been expressed as to whether monoculture is the only way to maximize biomass productivity. Subtropical forests in China are not only rich in tree species but are also diverse in terms of topography. However, historical clear-cutting and the high demand for wood have meant that considerable areas of these forests have been degraded or lost entirely. In recent years, great efforts have been made in subtropical China to restore and afforest vast areas. Nonetheless, conifer monoculture plantations are still prevalent owing to the lack of data on the relationship between diversity and ecosystem functioning and the limited knowledge of the growth performance of native broad-leaved tree species in plantations in this region. In this study, we investigated the growth response of individual tree saplings in a large-scale forest biodiversity and ecosystem functioning (BEF) experiment established in a highly heterogeneous environment in subtropical China (BEF-China). The experiment was established during the period November 2008 to April 2009 and incorporates a species pool of 24 tree species across 261 plots (0.067 ha each) and a broad richness gradient with 1-24 species per plot. Annual growth rates of tree height, stem diameter and crown width for 6723 saplings of 24 species in the third year after establishment were used as response variables. We analyzed the effects of initial size, local abiotic site conditions and local neighborhood on growth performance using mixed effects models. Initial size, local topographic (aspect, slope, curvature, elevation) and edaphic variables (total nitrogen, C/N ratio) as well as local neighborhood variables (competition index, Shannon index) were included as fixed effects. Random effects were plot and species identity. The results showed that growth performance of tree saplings was markedly species-specific and strongly affected by initial size and local site conditions. In this early stage of the experiment, local Shannon diversity did not yet explain a significant amount of variation in sapling growth. However, the significant effect of the increasing size of neighboring trees indicated that tree-tree interactions had already occurred. A greater investment in height growth at the expense of diameter growth suggested that light intercept is the priority for tree sapling growth. This study stresses the importance of better understanding the effects of local site conditions on initial growth in mixed-species plantations. [ABSTRACT FROM AUTHOR]

Abstract: Global warming presents a threat to plant species distributed at montane or alpine altitudes if the topography does not allow upward shifts in distribution ranges. Nevertheless, the species might also benefit from increasing temperatures and secondary effects on dominant species (e.g. bark beetle outbreaks or summer drought affecting the canopy species). As a consequence, disturbance frequency in montane forests might increase and light availability for herb layer species will increase. We addressed these interactions in a common garden experiment in Central Germany at different altitudes, representing cold and moist vs. warm and dry conditions. We investigated three montane species with different life forms, including a herb (Trientalis europaea), a grass (Calamagrostis villosa) and a dwarf shrub (Vaccinium myrtillus) under three shading treatments (3%, 28% and 86% of full sunlight). We hypothesized that montane species are at a disadvantage in the lowland, with the dwarf shrub suffering more than the grass. Furthermore, we hypothesized an antagonistic interaction of increased temperature and increased light conditions. While T. europaea and V. myrtillus showed only slightly responses to low altitude conditions, C. villosa displayed a nearly fifteen fold increase in biomass production, despite higher observed herbivory levels in the lowland. We failed to show an antagonistic effect of increased temperature and increased light availability, as all study species suffered from deep shade conditions and grew best under full light conditions at both sites. In conclusion, both improved temperature and light conditions might be principally beneficial for the investigated boreal species, in particular for the grass species C. villosa. [Copyright &y& Elsevier]

Abstract: Different plant species make use of resource gradients such as light in different ways. First, plant species specialize in using different parts of the gradient, resulting in niche partitioning, Second, within the section of the gradient used by a species, plants respond to a different resource supply by plasticity. Our study addressed both of these strategies, with the main objective to relate mean responses and plasticity indices of seedlings of woody species to species characteristics such as leaf habit and to variation in branch lengths and local frequency of adult trees in forest communities. A greenhouse experiment with 36 deciduous and 35 evergreen subtropical tree and shrub species was carried out to test the influence of light and nutrient availability on trait expression and plasticity of the species. The greenhouse responses of seedlings were compared with adult individuals in the field, based on a set of 46 species that occurred also in the 27 permanent plots in a secondary subtropical broadleaved forest in Zhejiang Province (SE-China). In the greenhouse experiment, most variables showed significant differences between unshaded (250μEm−2 s−1) and shaded (10μEm−2 s−1) treatments as well as between high and low nutrient supply. Deciduous species were more plastic than evergreen species in their response to light. No significant correlations were detected in mean responses and plasticity between juvenile plants in the greenhouse and adult trees in the field. However, some trait values such as biomass and node density as well as plasticity of several traits were positively related to the species’ abundance in the field, suggesting that locally abundant species tend to be less “plastic” than locally rare species. [Copyright &y& Elsevier]

Abstract: Norway spruce (Picea abies (L.) Karst.) exhibits strong ecotypic variation along altitudinal gradients in morphological traits, e.g. slenderness of crowns or arrangement of second-order branches. We were interested whether montane and lowland morphotypes differ in a key trait for the survival in cold environments, i.e. frost hardiness, and asked: (i) are montane morphotypes more resistant to frost damage and (ii) do they have a lower risk of frost damage by late frosts in spring than lowland morphotypes? We used the electrolyte leakage-method to measure frost hardiness on a monthly basis from October 2006 to May 2007 in stands of the montane and lowland morphotypes at Mt. Brocken in the Harz Mountains, Germany. LT50 (i.e. the temperature that results in 50% of maximum electrolyte leakage) was assessed by freezing treatments in a frost chamber and was significantly influenced by morphotype, month and minimum ambient temperatures. LT50 was significantly lower in the montane than in the lowland morphotype, with −107°C and −49°C, respectively. However, the interactions between morphotype with minimum ambient temperature or month were not significant. Thus, as frost hardiness of the two morphotypes responded to temperature in the same way, both morphotypes can be supposed to be exposed to the same risk of frost damage during hardening in autumn and dehardening in spring. [Copyright &y& Elsevier]

Abstract: Establishing the competitive relationships at the local neighbourhood level is essential for improving our understanding of tree growth dynamics in structurally heterogeneous and species-rich forests. We studied the competitive interactions influencing individual-tree five-year radial growth of the two species Castanopsis fargesii (Franch.) and Quercus fabri (Hance) in a diverse young secondary evergreen broad-leaved forest (EBLF) in eastern China. Different spatially explicit individual-based competition indices were examined for their effectiveness at predicting radial growth. These indices were based on one of the three tree size variables – diameter at breast height (dbh), total height, and crown projection area – and were combined with different approaches to identify potential competitors. Furthermore, we tested for competitive equivalence of conspecific and heterospecific neighbours and analysed the effects of local diversity, initial dbh (measured at the beginning of the five-year growth period) and abiotic environmental variables on individual-tree radial growth. Competition accounted for up to 78% and 75% of radial growth variation in C. fargesii and Q. fabri, respectively. The best results were provided by competition indices using crown projection area as the variable describing tree size and the angular height method as the approach to identify potential competitors (i.e. neighbours greater than the minimum angular height, measured from the base of the target trees, are selected as competitors). Competitive equivalence of conspecific and heterospecific neighbours was found in C. fargesii, whereas heterospecifics were stronger competitors than conspecifics in Q. fabri. We could not detect diversity effects on radial growth. The addition of initial dbh or abiotic environmental variables as further explanatory variables failed to improve the predictive ability of growth models. Our results indicate that diameter growth in this EBLF is largely a function of local neighbourhood competition and suggest that the mode of competition is primarily size-asymmetric. It appears that there may be high competitive equivalence among different species, but this remains to be experimentally tested. [Copyright &y& Elsevier]

Copyright of Basic & Applied Ecology is the property of Urban & Fischer Verlag and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: Trees are able to respond to their local biotic and abiotic environment with morphological adjustments which improve resource acquisition and, thus, growth. In forests, light is broadly recognised as one of the major factors determining growth, and morphological responses comprise changes in crown architecture and stem stature. On sloping terrain, the interplay of phototropism and gravitropism may further affect morphological growth characteristics. However, different tree species are expected to show species-specific responses. In this study, we analysed three growth characteristics of tree individuals belonging to four species of two functional groups (evergreen: Schima superba, Castanopsis eyrei, deciduous: Quercus serrata var. brevipetiolata, Castanea henryi) in a species-rich Chinese subtropical forest. Crown projection area, relative crown displacement and stem inclination were related to biotic (local species richness, functional richness, competition, stand age) and abiotic (slope aspect and inclination, soil depth) variables in the local neighbourhood of the tree individuals. We hypothesised that (i) there are species-specific differences in the morphological response of crown architecture and stem stature and (ii) that crown size and asymmetry as well as stem inclination are influenced by both, biotic and abiotic factors. In contrast to our expectations we were unable to reveal any species-specific differences in any of the three growth characteristics. The results of mixed effects models showed that crown area was mainly affected by the target tree''s dbh and biotic variables related to neighbours (competition, functional diversity), whereas stem inclination was mainly influenced by slope. Relative crown displacement was influenced by both, biotic and abiotic variables. We conclude that growth responses resulting in crown displacement and stem inclination seem to be an important mechanism to ameliorate foraging for light in our study area, but that these responses appear to be species-independent. The interplay of stem inclination and crown displacement allows for a plastic response of tree individuals in biotically and abiotically heterogeneous environments. Our results indicate that forest management in this region should focus on functionally diverse stands which are promoting crown area positively resulting in increased growth rates of individual trees. [Copyright &y& Elsevier]

Abstract: To assess the influence of gap age and microsite type within a near-natural montane Norway spruce stand at the Harz National Park in Germany, we tested the following hypotheses: (1) The relationship between Picea abies regeneration and gap age is represented by an optimum curve. (2) Within gaps, tree regeneration mainly occurs on gap-induced microsites. (3) The contribution of specific microsites to regeneration changes with gap age. We randomly established 90 permanent plots stratified into three gap age classes as well as undisturbed forest to assess the density of gap-induced microsites (logs, stumps, root plates) and of microsites not related to disturbance (forest floor, moss-covered rocks) and recorded relative light conditions, spruce density and biometric variables. We found significant differences in spruce regeneration between microsites as well as between undisturbed and disturbed plots. Sapling density was only related to microsite type, with the highest density being encountered on logs with 2.3 individuals/0.25m2, in contrast to moss-covered rocks with 1.8 individuals/0.25m2. Logs also ranked, together with root plates, highest in terms of sapling mortality. A larger density of young saplings on gap-induced microsites was compensated for by a higher mortality rate, probably due to self-thinning. In contrast, survival was highest on ordinary microsites, i.e. intact ground. Biometric variables differed significantly between microsites as individuals on ordinary microsites were taller than individuals on gap-induced microsites (94.21±137.09cm versus 39.86±50.45cm) and had more whorls (12.32±10.55 versus 7.73±6.79). Significant interactions between gap age class and microsite type were only evident in growth rates. In conclusion, although gap-induced microsites enhance spruce establishment, their role in long-term regeneration has been widely overestimated when compared to the relevance of the ordinary microsites, in particular as the latter are permanent and do not depend on disturbances. [Copyright &y& Elsevier]

Abstract: We analyzed indices of gap dynamics, i.e. gap formation and gap closure rates as well as turnover rates, in a montane conifer forest in the temperate zone and asked: (1) Are the characteristics of gap dynamics comparable with those of other temperate forests? (2) Do gap dynamics exhibit temporal trends, and (3) if so, are they related to recent climate change? We also addressed methodological issues concerning the differences observed at differing temporal and spatial scales of the used datasets. Thus, we asked further how the indices of gap dynamics are influenced (4) by differences in the length of observation periods and (5) by differences in gap size categories included in the study? The study area was located in the near-natural Picea abies forests in the core zone of the Harz National Park on the north-eastern slopes of Mt. Brocken, Germany. From this area, aerial photographs from the last 60yrs (1945, 1991, 2000, 2003) were analyzed by GIS techniques. Total gap area, number of gaps, gap size and area-based turnover rate, rotation time, gap formation and gap closure rate were calculated and correlated with climate variables. The total gap area varied between 10.9ha and 19.0ha for the study area of 225.2ha between the different years. Similarly, the median of the gap size was 155.6m2 and 87.0m2 in 1945 and 2003, respectively. A rotation time of 228yrs was calculated for the study area. Area-based turnover rates and gap formation rates increased with time, while mean gap size decreased. The most frequently recorded gaps were those in the category <100m2. In particular, small gaps at the level of single trees (≤40m2) became more frequent in the last decade and showed a higher gap formation rate than larger gaps. Temperature was significantly related to both turnover and gap closure rates. In conclusion, for the near-natural spruce stands at Mt. Brocken indices of gap dynamics were of a magnitude comparable to those described from other forest types in the temperate zone. However, the indices of gap dynamics increased with time, which coincided with increasing temperatures over the last few decades. [Copyright &y& Elsevier]

Abstract: The objective of this study was to test relationships between gap size, gap age and performance of the pseudoannual forest herb layer species Trientalis europaea. We also tested for a potential covariation of performance variables with light as the putative driving factor of gap size and gap age effects. The study took place in the core zone of the Harz National Park in a near-natural spruce forest at Mt. Brocken, Germany. We established 70 randomly distributed plots of three different gap age classes (<15 years, >15 and <60 years, >60 years) and undisturbed forest stands. We recorded growth variables of Trientalis (e.g. height of ramets, number of flowers and fruits per ramet and number of daughter tubers per ramet) and measured PPFD (photosynthetic photon flux density). Gap sizes were assessed with GPS, ranged from 131m2 to 16400m2 and were independent from gap age. Population density of T. europaea was neither affected by gap size nor by gap age. However, gap age had an effect on the fitness of Trientalis ramets. In gaps, the species produced a higher number of flowers and fruits. In general, the average proportion of flowering and fruiting was very low, with 13% and 4%, respectively. In contrast, light intensity had a significant positive effect on ramet density, while the number of daughter tubers differed between 0.8 and 0.5 tubers per individual under lowest light and full light intensity, respectively. The general conclusion is that gap size had no effects on the performance of T. europaea, while gap age had both direct effects and indirect effects mediated by light. [Copyright &y& Elsevier]

Copyright of Basic & Applied Ecology is the property of Urban & Fischer Verlag and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: Seedling establishment as the life stage transition most sensitive to herbivory might be impossible even if the herbivory losses suffered by adult plants of the same species are tolerable. We tested the hypothesis that herbivory impedes seedling establishment of two montane Asteraceae species on their lower altitudinal distribution border. In a submontane meadow in the Harz Mountains, Germany, the montane grassland perennials Arnica montana and Centaurea pseudophrygia (Asteraceae) were sown into artificially created gaps of two different sizes, half of which were protected from slug grazing by molluscicide application in the initial phase of the experiments. The Arnica experiments started in spring and late summer of 1999 and in spring of 2000; whereas Centaurea was only sown in the spring of 2000. Seedling survival was monitored until the autumn of 2000. Ten weeks after sowing, mollusc exclusion resulted in significantly higher Arnica or Centaurea seedling numbers in all experiments; whereas grasses and dicotyledons that emerged from the seedbank were promoted by slug exclosure in only one experiment. Species diversity was not affected by molluscicide application. By the end of the second growing season, the survivorship of Arnica sown in the spring of 1999 was reduced to less than 1% of the number of sown seeds in the gaps with natural slug grazing, compared to 7–15% in the gaps with molluscicide treatment. Plant density of most species was higher in the small than in the large gaps, indicating a microclimatic shelter effect of the surrounding vegetation. The results show that slug herbivory might exert large effects on species composition in grassland; it does strongly influence the seedling establishment of the highly palatable, slow-growing A. montana, while the seedlings of C. pseudophrygia, although of similar palatability, are more able to tolerate slug feeding because of their higher growth rate. [Copyright &y& Elsevier]

Abstract: The objective of this paper is to analyse the degree to which the variation in soil conditions corresponds to the occurrence of specific plant species at micro-scale. The investigation was performed in beech forests with seven plant species growing on three sites with different geological substrates of the Triassic period (Muschelkalk, Oberer and Mittlerer Buntsandstein). At each site three to five plant species of ca. 20 individuals each were selected by stratified random sampling. The growth location of a plant individual was considered to be a potential microsite. At the gowth locations, soil solution was exctracted in situ by low tension lysimetry from the rooted topsoil exactly beneath the selected plant individuals. A soil sample was taken from the same spot and analysed for pH(H2O) and exchangeable cations. In addition, the vegetation was recorded around each target individual and species composition was related to chemical soil properties by multivariate analyses. The three sites were found to form a gradient with respect to most analysed soil parameters. Variation coefficients of soil properties increased in the sequence pH, exchangeable Ca, K, Mg, Al, Fe, Mn. Concentrations of cations in the soil solution varied to a higher degree than those of exchangeable cations with the sole exception of Fe that showed a lower variation in the soil solution. Averaged over all sites, the microsite values for pH and exchangeable Ca exhibited a distinct sequence for the investigated species with decreasing values in the root horizon in the sequence Mercurialis perennis, Arum maculatum, Lamiastrum galeobdolon, Galium odoratum, Viola reichenbachiana, Oxalis acetosella and Luzula luzuloides. Within sites, only few significant differences were found between the potential microsites of specific species. The microsites of species on Muschelkalk differed in pH, concentrations of exchangeable Ca and K and of Ca in the soil solution. The microsites on Mittlerer Buntsandstein differed in pH and concentration of exchangeable Fe. No significant differences between species were found on Oberer Buntsandstein. Species composition in a area of 3.14m2 around the sample locations varied only to a minor degree as was revealed by canonical correspondence analysis (CCA). In addition, the low level of encountered variation could only be explained to a small degree by the soil variables. It is concluded that the analysed environmental factors are of minor importance for fine-scale species occurrences. At a scale of meters or less, biotic parameters might exert a greater influence than soil parameters. [Copyright &y& Elsevier]

• The effect of fertilization on needle and root nutrient concentrations is via soil available N and P. • P contributes more than N fertilization to basal area increment during both seasons. • The opposite effects of N and P fertilizations on growth rate vary with season. Phosphorus (P) and nitrogen (N) are the major limiting nutrients for plant growth in most ecosystems. However, it is unclear whether P fertilization exhibits higher effects on plant growth than N fertilization and whether the effects vary with season, since plant demands for N vs. P vary differently during different seasons. We seasonally measured N and P concentrations of fine roots, leaves, and soil as well as growth in Chinese fir (Cunninghamia lanceolata) plantations fertilized with P (5 g m−2 a−1) and/or N (5 g m−2 a−1 and 10 g m−2 a−1) over five years in subtropical China. Needle N and P concentrations were significantly influenced by P fertilization, whereas root N and P concentrations were significantly influenced by P fertilization and the interaction between P fertilization and season. Phosphorus fertilization generally decreased root N concentration in the warm season and increased P concentrations of needle and root in the cold season. Moreover, root P concentration with P fertilization was significantly higher during the cold season than during the warm season, regardless of N fertilization. Contrary to the cold season, in the case of high N fertilization, basal area increment was significantly lower with than without P fertilization during the warm season. Nitrogen fertilization in the warm season had a positive effect on basal area increment, contrary to the cold season. Contrary to N fertilization, P fertilization had a negative effect on basal area increment in the warm season, whereas it had a positive effect in the cold season. Phosphorus fertilization contributed more than N fertilization to basal area increment during both seasons. Moreover, root P concentration was the most crucial factor determining basal area increment during both seasons. The opposite effects of N and P fertilizations on plant growth depend on the season in the Chinese fir plantation, which suggested that the timing of P and N fertilizations should be considered for the Chinese fir plantations in subtropical areas. [ABSTRACT FROM AUTHOR]

Investigating the effects of individual tree species on fungal species in leaf litter allows a mechanistic understanding of how tree diversity affects the diversity and composition of fungal species at the community level. We collected freshly-fallen leaves of eight focal tree species at four tree species richness levels in a large-scale subtropical forest diversity experiment to estimate tree species richness effects on fungal species diversity and community composition at two spatial scales: at the local tree neighbourhood and at the tree community level. The identity of focal tree species affected both the diversity and composition of the fungal community in freshly-fallen leaves, particularly structuring the composition of both the pathogenic and non-pathogenic fungal community. Furthermore, we found that the effects of community tree species richness on fungal OTU composition were tree species-specific. Besides community tree species richness, the neighbour tree community had significant effects on the structure of the entire fungal community and of functional groups in freshly-fallen leaves. These findings highlight that the response of fungal species assemblages to tree species richness depends on fungal-associated tree species identity, and suggest that heterospecificity of local tree neighbours is an important driver of tree richness effects on litter fungal community. • Focal tree species identity may structure litter fungal community. • Community tree richness effects on litter fungal species are tree species-dependent. • Heterospecificity of local tree neighbours is a key driver of tree richness effects. [ABSTRACT FROM AUTHOR]

There is growing interest in the application of plant functional trait-based approaches for development of sustainable land-use strategies. In this context, one crucial task is to identify and measure plant traits, which respond to land-use intensity (response traits) and simultaneously have an impact on ecosystem functions (effect traits). We hypothesized that species-specific leaf chemical composition, which may function both as response and effect trait, can be derived from Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR) spectroscopy tools in combination with multivariate statistical methods We investigated leaf ATR-FTIR spectra of two grasses, Poa pratensis L. and Dactylis glomerata L., and one forb, Achillea millefolium L. collected in grassland plots along a land-use intensity gradient in three regions of Germany. ATR-FTIR spectra appear to function as biochemical fingerprints unique to each species. The spectral response to land-use intensity was not consistent among species and less apparent in the two grasses than in the forb species. Whereas land-use intensification enhanced protein and cellulose content in A. millefolium , giving rise to changes in six spectral bands in the frequency range of 1088–1699 cm −1 , only cellulose content increased in D. glomerata , affecting the bands of 1385–1394 cm −1 . Poa pratensis spectra exhibited minimal changes under the influence of land-use, only in the spectral bands of 1373–1375 cm −1 associated with suberin-like aliphatic compounds. Our findings suggest that some species’ leaf chemical composition is responsive to land-use intensity, and thus, may have a predictive value for ecosystem services provided by those species within grassland vegetation (i.e., herbage yield quality). [ABSTRACT FROM AUTHOR]

A better understanding of the linkages between aboveground and belowground biotic communities is needed for more accurate predictions about how ecosystems may be altered by climate change, land management, or biodiversity loss. Soil microbes are strongly affected by multiple factors including local abiotic environmental conditions and plant characteristics. To find out how soil microbial communities respond to multiple facets of the local soil and plant environment, we analysed soil lipid profiles associated with three-year-old monocultures of 29 tree species. These species are native of the diverse subtropical forests of southeast China and greatly vary in functional traits, growth or biomass characteristics, and phylogenetic relatedness. Along with the traits of each tree species, we also determined the soil and plot characteristics in each monoculture plot and tested for phylogenetic signals in tree species-specific microbial indicators. Microbial community structure and biomass were influenced by both soil properties and plant functional traits, but were not related to the phylogenetic distances of tree species. Specifically, total microbial biomass, indicators for fungi, bacteria, and actinomycetes were positively correlated with soil pH, soil organic nitrogen, and soil moisture. Our results also indicate that leaf dry matter content and the leaf carbon to nitrogen ratio influence multivariate soil microbial community structure, and that these factors and tree growth traits (height, crown or basal diameter) positively promote the abundances of specific microbial functional groups. At the same time, a negative correlation between leaf nitrogen content and Gram positive bacterial abundance was detected, indicating plant–microbial competition for nitrogen in our system. In conclusion, even at early stages of tree growth, soil microbial community abundance and structure can be significantly influenced by plant traits, in combination with local soil characteristics. [ABSTRACT FROM AUTHOR]

Abstract: The attempt to identify traits associated with plant invasions has revealed ambiguous results to date. Accounting for environmental and temporal variation in multispecies trait comparisons of native and invasive species might help explain such inconsistency. The relative importance of light and nutrient availability was tested in a greenhouse experiment on trait expression and variation of 15 native and 15 invasive herb species from Southeast China. In addition, N uptake of a subset of these species and its temporal pattern were assessed by means of a 15N tracer experiment. A predominant lack of significant differences between the two status groups indicated strong overall trait similarities, thus supporting the ‘join-the-local’ hypothesis. However, at high light levels, the invasive species displayed significantly higher trait relative growth rates, whereas the native species had a higher tissue quality as displayed in a higher dry matter content of shoots and leaves. The invasion success of the invasive species could neither be explained by a general higher N uptake nor by a distinction in temporal N uptake strategy between native and invasive species. Despite comparable fundamental niches of the species, increased growth rates under beneficial light conditions may provide a head start advantage for invasive species compared to native ones. The present study confirms the assumption of an opportunistic strategy for invasive species and emphasizes the need to assess trait variation between native and invasive species in different environmental contexts. [Copyright &y& Elsevier]

Abstract: Intensity of ultraviolet-B radiation (UV-B) differs between northern and southern hemispheres. Therefore, exotic plants species that originate from the northern hemisphere provide an opportunity to study the effects of UV-B on plant physiology and growth, and their implications for the role of adaptation and phenotypic plasticity during plant invasion on the southern hemisphere. We conducted a growth-chamber experiment with and without UV-B on Hieracium pilosella plants from Germany, where the species occurs natively and New Zealand (NZ), where it is invasive. We tested the hypothesis that: (i) H. pilosella plants respond to UV-B with high phenotypic plasticity, demonstrating the ability to react to changes in UV-B, and (ii) NZ plants are better adapted to UV-B than German plants as a result of directional selection of well adapted phenotypes. Consistent with our first hypothesis H. pilosella plants reacted plastically to UV-B by producing longer foliar hairs and a higher leaf dry matter content (LDMC) when they were treated with UV-B regardless of their origin. Additionally, irrespective of the treatment, plants from NZ displayed a higher LDMC and grew less but longer leaves than German plants. Plants showed typical stress responses and a reduction in growth caused by the UV-B treatment: below-ground biomass and production of ramets were reduced when plants were treated with UV-B. H. pilosella proved to be particularly well predisposed to grow in areas of high UV-B radiation. Our findings hint at the necessity to consider UV-B radiation in future research on mechanisms of invasions in regions with high UV-B irradiation. Species that provide the ability to respond directly to UV-B might have an advantage to invade these areas. As UV-B intensity is likely to change in the future due to ongoing ozone depletion, research addressing the effects of UV-B during plant invasions is of increasing importance. [Copyright &y& Elsevier]

Abstract: The establishment and survival of young individuals of five desert phreatophytes that form dominant or codominant stands round river oases at the southern rim of the Taklamakan Desert was studied to explain the patterns observed in the established vegetation. We hypothesized to find differences between species in the rates of establishment and survival as well as in the susceptibility to grazing. We expected species that grow at largest distances to the groundwater table to establish themselves more successfully and have higher survival rates. In addition, we expected the high grazing and browsing pressure in the oasis foreland to have a negative effect on seedling establishment, with less palatable species being less affected. Exclosure experiments were carried out along the banks of an ephemeral river. Seedlings and shoot or rhizome fragments were planted in either fenced or control plots. In addition, the naturally emerging seedlings after a flooding event were monitored for survival to the subsequent vegetation period. In contrast to expectations, the species did not differ in the survival of planted seedlings and vegetative fragments. However, there were significant differences in the density of spontaneously emerging seedlings. Tamarix ramosissima had a much higher seedling density than the other species. Excluding livestock had a positive effect on the survival of planted seedlings and shoot or rhizome fragments. However, there were no species-specific exclosure effects neither effects on the survival of spontaneously emerging seedling. The exclusion of grazers and browsers might generally enhance the vegetation coverage in the oases forelands, but it does not favour different species disproportionately. In conclusion, the species’ regeneration niches explain only partly the patterns encountered in the established vegetation. [Copyright &y& Elsevier]

There is increasing concern regarding how plant diversity affects litter decomposition. However, few experiments have simultaneously investigated the independent effects of litter species composition and the richness of above-ground tree communities on litter decomposition. To elucidate the two facets of diversity effects on leaf litter decomposition, a field experiment with litterbags containing monospecific or mixed litter of Schima superba , Cyclobalanopsis glauca , and Castanopsis eyrie was conducted for 30 consecutive months in a subtropical forest. In addition, the fungal community composition of the decomposing litter was assessed in the later decomposition stage. Our results revealed that leaf litter species composition but not litter species richness per se affected decomposition rates, in which the decomposition rates were faster in the presence of S. superba litter but slower in the presence of C. eyrei litter. Soil properties showed stronger impacts on litter mass loss in the earlier stages, while the litter species composition became more important in the later stage. Moreover, above-ground tree species richness had a significant effect on leaf litter decomposition. As expected, the effects of above-ground tree species richness and litter species composition became much stronger with time, probably owing to the indirect effects of concomitant changes in the composition of the litter fungal community, which in turn depended on the changes of microenvironment or on accumulated recalcitrant substances in the late stage of decomposition. Overall, our findings demonstrate that not only litter species composition but also above-ground tree species communities play critical roles in regulating litter decomposition, particularly in the late stage. An investigation into the interactions between plant and decomposer communities is required to gain a full understanding of the mechanisms underlying litter mixture decomposition. • Litter composition affected decomposition rates, while litter richness did not. • Litter decomposition was significantly affected by above-ground tree richness. • Above-ground tree richness and litter composition strongly affected fungal community. • Effects of above-ground tree richness and litter composition varied temporally. [ABSTRACT FROM AUTHOR]

Leaf litter decomposition is closely linked to soil nutrient cycling. Both vary with environmental conditions, leaf litter diversity, faunal decomposer community and leaf litter chemistry. Polyphenols, i.e. phenolics and tannins, are important secondary metabolites in leaf litter and are considered a major impediment to whole-leaf decomposition. While the function of polyphenols is well studied, the mechanisms and drivers of their decomposition are largely unknown. We reasoned that polyphenol decomposition is driven by the same factors as whole-leaf decomposition. We hypothesized that polyphenol decomposition rates increase with leaf litter richness, decrease with macrofauna exclusion and are related to traits characterizing leaf litter quality. We measured decomposition rates of polyphenols in leaf litter of seven subtropical Chinese tree species, sampled at five dates and in a fully factorial design that manipulated litter richness and macrofauna access. We further estimated leaf carbon and nitrogen contents and leaf toughness using near-infrared spectroscopy. We showed that 1) phenolics and tannin decomposition rates did not depend on leaf litter species richness, 2) the decomposition rates of phenolics and tannins were up to one magnitude higher than whole-leaf decomposition rates, 3) the exclusion of macrofauna increased phenolics and tannin decomposition rates, 4) the leaf nitrogen content positively affected the phenolics decomposition rates and 5) the tannin-to-nitrogen ratio was the best predictor of whole-leaf decomposition. We conclude that the fast decomposition of phenolics and tannins in the early stages of whole-leaf litter decomposition is an essential ecological process. Low molecular weight phenolics that enter the soil can accelerate microbial growth, while potentially toxic tannins leave the leaf tissue, and thus, enable the consecutive whole-leaf decomposition. Our study is the first to show that macrofauna occurrence negatively affects the decomposition of ecological relevant secondary plant metabolites. This points to the importance of considering biotic interactions between different trophic levels to fully understand the mechanisms of leaf litter decomposition. • Litter species identity rather than litter diversity drives polyphenol decomposition. • Soil macrofauna negatively affects the decomposition of secondary plant metabolites. • Leaf nitrogen content positively affects the phenolics decomposition rates. • Tannin-to-nitrogen ratio is best predictor of whole-leaf decomposition. [ABSTRACT FROM AUTHOR]

Abstract A major gap in understanding the relationship between tree diversity and litter decomposition concerns knowledge of the saprotrophic fungal communities mediating decomposition processes. Making use of experimental tree diversity plots in subtropical China, our objective was to disentangle the effects of tree species richness on diversity, abundance, and composition of saprotrophic fungal communities in freshly fallen leaf litter. We employed a meta-genomic approach and analysed enzymatic decomposition. Our results indicate the dominance of Ascomycota, with species from this phylum colonizing leaf litter more rapidly than Basidiomycota. Furthermore, Ascomycota was the most abundant when tree richness was intermediate. Both Ascomycota and Basidiomycota differed significantly in their species composition in response to varying tree species richness. However, saprotrophic fungal species diversity did not respond to tree species richness. Instead, litter C/N ratio, litter Ca and plot altitude were the strongest determinants of fungal species diversity. Carbon-degradation enzyme activities were also significantly associated with litter C/N ratio, Ca and Fe concentration and, in addition, with tree species richness. The responses of fungal species and enzyme activity to tree species richness were uncoupled from each other, although the two variables were significantly correlated. Overall, our findings highlight a significant effect of tree species richness on litter fungal species composition, but not diversity. Our findings also provide insight into the importance of enzyme-mediated C degradation for the response to tree species richness in early-stage leaf decay in subtropical forests. Highlights • Fungal diversity in litter did not respond to the increase of tree species richness. • Tree richness affect Ascomycota composition rather than Basidiomycota fungi. • Ascomycota fungi were highest at intermediate tree species richness level. • Carbon degradation-related enzymes were significantly affected by tree richness. [ABSTRACT FROM AUTHOR]

Despite considerable research demonstrating that biodiversity increases productivity in forests and regulates herbivory and pathogen damage, there remain gaps in our understanding of the shape, magnitude, and generality of these biodiversity-ecosystem functioning (BEF) relationships. Here, we review findings from TreeDivNet, a global network of 25 tree diversity experiments, on relationships between levels of biodiversity and (a) tree growth and survival and (b) damage to trees from pests and pathogens. Tree diversity often improved the survival and above- and belowground growth of young trees. The mechanistic bases of the diversity effects on tree growth and survival include both selection effects (i.e., an increasing impact of particular species in more species-rich communities) and complementary effects (e.g. related to resource differentiation and facilitation). Plant traits and abiotic stressors may mediate these relationships. Studies of the responses of invertebrate and vertebrate herbivory and pathogen damage have demonstrated that trees in more diverse experimental plots may experience more, less, or similar damage compared to conspecific trees in less diverse plots. Documented mechanisms producing these patterns include changes in concentration, frequency, and apparency of hosts; herbivore and pathogen diet breadth; the spatial scale of interactions; and herbivore and pathogen regulation by natural enemies. Our review of findings from TreeDivNet indicates that tree diversity experiments are extending BEF research across systems and scales, complementing previous BEF work in grasslands by providing opportunities to use remote sensing and spectral approaches to study BEF dynamics, integrate belowground and aboveground approaches, and trace the consequences of tree physiology for ecosystem functioning. This extension of BEF research into tree-dominated systems is improving ecologists’ capacity to understand the mechanistic bases behind BEF relationships. Tree diversity experiments also present opportunities for novel research. Since experimental tree diversity plantations enable measurements at tree, neighbourhood and plot level, they allow for explicit consideration of temporal and spatial scales in BEF dynamics. Presently, most TreeDivNet experiments have run for less than ten years. Given the longevity of trees, exciting results on BEF relationships are expected in the future. [ABSTRACT FROM AUTHOR]

Earthworms have a significant influence on the structure, composition and functioning of forest ecosystems, but in spite of their role as ecosystem engineers, little is known on the factors controlling their distribution across European forests. Optimised sampling techniques, as well as more advanced statistical tools and geographical information systems have facilitated studies at the landscape scale. But these, and even larger-scale studies, are scarce due to data limitations, taxonomic inconsistencies and practical issues in linking existing databases. In this continental-scale field-based study we used boosted regression tree modelling to identify and evaluate the relative importance of environmental factors explaining earthworm incidence (presence/absence) and abundance (density and biomass) in European forests. To parameterise our models earthworms were sampled in six forest landscapes along a latitudinal gradient from the boreal north to the Mediterranean south in spring or autumn of 2012, together with several environmental variables. Earthworms were sampled using a combined method of mustard extraction and hand sorting of litter and a soil monolith, after which they were weighed and identified to functional group (epigeic, endogeic and anecic). We found that litter- and soil-related variables best explained earthworm incidence and biomass in European forests, leaving only a minor role to climate-related variables. Among the litter related variables, understory vegetation played an important role in explaining earthworm incidence and abundance. The relative importance of explanatory variables differed between models for incidence, density and biomass and between earthworm functional groups. Our results suggested that threshold values for soil C:N ratio, forest floor pH and understory plant biomass and plant nutrient concentrations have to be attained before earthworms can occur. Beyond these threshold values, variables like soil C:N ratio, tree litter C:P ratio and forest floor mass further explain earthworm biomass. Mechanisms behind these observations are discussed in the light of future earthworm distribution modelling at continental scale. [ABSTRACT FROM AUTHOR]

Understanding how communities respond to environmental gradients is critical to predict responses of species to changing habitat conditions such as in regenerating secondary habitats after human land use. In this study, ground-living ants were sampled with pitfall traps in 27 plots in a heterogeneous and diverse subtropical forest to test if and how a broad set of environmental variables including elevation, successional age, and tree species richness influence ant diversity and community composition. In total, 13,441 ant individuals belonging to 71 species were found. Ant abundance was unrelated to all environmental variables. Rarefied ant species richness was negatively related to elevation, and Shannon diversity decreased with shrub cover. There was considerable variation in ant species amongst plots, associated with elevation, successional age, and variables related to succession such as shrub cover. It is shown that younger secondary forests may support a species-rich and diverse community of ants in subtropical forests even though the species composition between younger and older forests is markedly different. These findings confirm the conservation value of secondary subtropical forests, which is critical because subtropical forests have been heavily exploited by human activities globally. However, the findings also confirm that old-growth forest should have priority in conservation as it supports a distinct ant community. Our study identifies a set of ant species which are associated with successional age and may thus potentially assist local conservation planning. [ABSTRACT FROM AUTHOR]

Abstract: One of the current advances in functional biodiversity research is the move away from short-lived test systems towards the exploration of diversity-ecosystem functioning relationships in structurally more complex ecosystems. In forests, assumptions about the functional significance of tree species diversity have only recently produced a new generation of research on ecosystem processes and services. Novel experimental designs have now replaced traditional forestry trials, but these comparatively young experimental plots suffer from specific difficulties that are mainly related to the tree size and longevity. Tree species diversity experiments therefore need to be complemented with comparative observational studies in existing forests. Here we present the design and implementation of a new network of forest plots along tree species diversity gradients in six major European forest types: the FunDivEUROPE Exploratory Platform. Based on a review of the deficiencies of existing observational approaches and of unresolved research questions and hypotheses, we discuss the fundamental criteria that shaped the design of our platform. Key features include the extent of the species diversity gradient with mixtures up to five species, strict avoidance of a dilution gradient, special attention to community evenness and minimal covariation with other environmental factors. The new European research platform permits the most comprehensive assessment of tree species diversity effects on forest ecosystem functioning to date since it offers a common set of research plots to groups of researchers from very different disciplines and uses the same methodological approach in contrasting forest types along an extensive environmental gradient. [Copyright &y& Elsevier]

Various environmental challenges are rapidly threatening ecosystems and societies globally. Major interventions and a strategic approach are required to minimize harm and to avoid reaching catastrophic tipping points. Setting evidence-based priorities aids maximizing the impact of the limited resources available for environmental interventions. Focusing on protecting both food security and biodiversity, international experts prioritized major environmental challenges for intervention based on three comprehensive criteria – importance, neglect, and tractability. The top priorities differ between food security and biodiversity. For food security, the top priorities are pollinator loss, soil compaction, and nutrient depletion, and for biodiversity conservation, ocean acidification and land and sea use (especially habitat degradation) are the main concerns. While climate change might be the most pressing environmental challenge and mitigation is clearly off-track, other issues rank higher because of climate change's high attention in research. Research and policy agendas do not yet consistently cover these priorities. Thus, a shift in attention towards the high-priority environmental challenges, identified here, is needed to increase the effectiveness of global environmental protection. Unlabelled Image • We must prioritize global biodiversity and food threats for effective protection. • Our comprehensive prioritization included importance, neglect, and tractability. • Pollinator loss and soil degradation are top priorities for food security. • Biodiversity is best served by combatting ocean acidification and land use change. • Our results call for a shift in attention towards the high-priority challenges. [ABSTRACT FROM AUTHOR]