Bryophyte Species Richness Research Articles

Bryophytes in managed lowland forests of Slovakia (Central Europe): looking into species diversity across different forest types

AbstractThe majority of the woodland area in Central Europe is composed of managed forests. Although the species diversity and composition, particularly in older forests, may be similar to those of natural or close-to-nature forests, intensive forestry and other human activities have adverse impacts on biodiversity. The present study focused on bryophyte diversity in managed lowland forests, as these have received less attention compared to other types of forests. Our research targeted the area located within the Borská nížina Lowland in south-western Slovakia. In total, 37 forest sampling plots (SPs) were selected, representing five different forest types, namely Quercus, Fraxinus, Robinia, Pinus, and mixed forests. Multivariate statistical analyses were conducted across these forest types to demonstrate variations in bryophyte species richness, composition, and functional traits. Overall, 60 species of bryophytes were identified, of which five were liverworts and 55 were mosses. Epiphytes were the most abundant substrate group in deciduous and mixed stands, while epigeic species prevailed in Pinus forests. Considering environmental factors, the bryophyte diversity was influenced mostly by the forest type and area size of SPs. Clear differences in species composition were observed when comparing coniferous and deciduous stands, as well as non-native Robinia forests and native tree stands. Overall, intensive forest management results in a high concentration of hemerophilous and nitrophilous species, along with the absence of rare and threatened mosses and liverworts. Nevertheless, by adhering to proper management methods, even managed forests can provide suitable habitats for various bryophytes.

Seeking a Hideout: Caves as Refuges for Various Functional Groups of Bryophytes from Terceira Island (Azores, Portugal)

Caves represent sites of great geological and biological interest. For most taxonomic groups, caves represent one of the most challenging ecosystems due to their extreme conditions. However, these places are rich in biodiversity, and some groups, such as bryophytes, can take advantage of these conditions. Bryophytes from twelve caves on Terceira Island (Azores archipelago) were sampled and compared in terms of species richness, abundance, and composition. The results revealed a high species richness of bryophytes, with one-fifth of the species being threatened and one-third endemic. Moreover, the dominance of bryophyte species, as determined by different functional groups, varies depending on the sampled cave and, consequently, the environmental variables. This is evident from the high β-diversity values obtained, demonstrating significant dissimilarities in species composition among the surveyed caves. Both macro- and microclimatic variables significantly influenced the richness and abundance of bryophyte species in different ways, depending on the functional group studied. Highlighting bryophyte diversity in cave environments, this study points to the need for effective management strategies to preserve and protect these unique and ecologically significant communities. These places can serve as refuges for some species, even for bryophytes, a taxonomic group with a long-distance dispersal strategy.

Effects of the Abandonment of Traditional Cultural Practices on Epiphytic Bryolichenic Communities in Chestnut Orchards in North-West Spain

This study delves into the impact of contrasting management practices on epiphytic bryolichenic communities, shedding light on their divergent responses to management regimes on Castanea sativa Mill. orchards. Lichens and bryophytes were sampled in managed and abandoned plots, in 95 trees, in north and south sides and at two heights in Galicia (NW Spain). The studied groups exhibited opposing reactions to these management practices; bryophytes suffered adverse effects in managed stands, experiencing reduced cover and species richness compared to abandoned orchards, while lichens displayed heightened cover and species diversity. The size of trees, included as a covariate in our analyses, displayed no significant impact on the overall species richness of lichens or bryophytes, although it did influence the cover of specific functional traits. These differing outcomes may be linked to alterations in environmental conditions brought by management interventions. Furthermore, the study uncovered divergent responses within the taxonomic and functional composition of epiphytic communities. Different species and functional groups exhibited varying reactions to changing environmental conditions, making predictions a complex endeavour. In conclusion, this research emphasizes the need for management strategies that account for the diverse ecological requirements of different species and functional groups since no single management regime will suit all species or functional groups.

Bryophytes in classification and ecology of calcareous beech forests in Central Slovakia

Traditionally, calcareous beech forests were classified and differentiated according to vascular plants. Bryophytes were often omitted or not all substrates were sampled in relevés, and therefore, the role of bryophytes in plant community differentiation remained unclear. In this paper, we studied bryophyte species richness, composition and functional patterns in vegetation units differentiated by vascular plants. We analysed 45 phytosociological relevés from 400 m2 plots in Fagus sylvatica-dominated forests on dolomite bedrock in Central Slovakia. The most frequent among 59 moss and 8 liverwort species was Tortella tortuosa, followed by Hypnum cupressiforme, Brachytheciastrum velutinum and Ctenidium molluscum. Average richness of bryophytes was 8.1 compared to 38.7 species of vascular plants. Seven bryophyte species were significantly linked to a particular vegetation unit. One-way ANOVA showed no noticeable differences in bryophyte species richness between vegetation units. However, it was negatively affected by xericity and positively by cover of rocks on soil surface. CCA revealed that species composition was affected significantly by xericity, cover of bare rocks and cover of tree layer. Mat and turf life forms prevailed, and both long-lived taxa/perennials and short-lived colonists formed the bryophyte layer. Observed bryophyte species grew mostly on rock, living and dead wood, and only minority of them on soil. Therefore, available substrates greatly contributed to the species richness of bryophytes and total plant diversity of the forest community. A complete investigation of substrates is necessary to assess the drivers of bryophyte species distribution and diversity, and their role in classification of calcareous beech forests.

How does understory vegetation diversity and composition differ between monocultures and mixed plantations of hybrid poplar and spruce?

Although monocultures are important for timber production, they are often associated with lower biological diversity than mixtures. Thus, mixed plantations have been suggested as a way to enhance biodiversity because of their inherent compositional diversity. However, the effects of monocultures versus mixtures on understory diversity and composition can vary in different ecosystems. The objective of this study was to assess how monocultures and mixed plantations influence understory vegetation diversity and composition in the boreal forest region of southern Quebec. We sampled plantations established with deciduous Populus trichocarpa Torrey & A. Gray × balsamifera L. and P. maximowiczii Henry × balsamifera L. and coniferous Picea abies (L.) Karst. and Picea glauca (Moench) species planted in monocultures and in mixed plantations on abandoned farmlands and a forest site. We assessed understory vegetation diversity and composition in each canopy type (coniferous, deciduous, mixed) and in each plantation type. We evaluated bryophyte and lichen diversity and composition specifically in tree microhabitats: soil, tree bases, and tree trunks. We found that vascular plant and lichen species richness was similar in all plantation types, while bryophyte species richness was higher in spruce monocultures and in mixed plantations compared to poplar monocultures. Our results also highlight how land-use history influenced vascular plant composition as abandoned farmland sites were composed of more ruderal vascular plants, while the previously forested site was composed of species found in natural forests. In the context of reforestation and plantations, our study suggests mixing spruce with poplars to maximize understory vegetation diversity as the addition of spruce in mixed plantations promoted the establishment of terrestrial bryophytes, while poplars favored the establishment of epiphytic lichens.

Resurvey studies of terricolous bryophytes and lichens indicate a widespread nutrient enrichment in German forests

AbstractQuestionsVegetation resurveys, both single studies and meta‐analyses, have predominantly been based on vascular plant data while bryophytes and lichens have largely been neglected. Our study aims to fill this gap and addresses the following research questions: has the overall species richness of terricolous bryophytes and lichens in forests changed over time? Which are the winners and losers among single species and ecological species groups? Do the results give a signal of the impact of nutrient enrichment, of changes in the light regime and of climate change?LocationDeciduous and coniferous forests in Germany.MethodsWe compiled 35 single resurvey data sets, including 1096 plots in total (each sampled twice). The time interval between initial surveys and resurveys ranged from 10 to 65 years. The differences between old and new plots were analysed with respect to the frequency of single species, total species richness, and the absolute and relative numbers of taxa in the species groups. Trend scores of species were related to ecological indicator values to identify the main environmental drivers behind the observed changes.ResultsTotal species richness did not systematically change, while pleurocarpous mosses had increased at the expense of acrocarpous mosses and, in coniferous forests, of lichens. Weak changes were generally observed in deciduous forests on base‐rich soils. In coniferous forests and in deciduous forests on acid soils, species with high nitrogen demand and high shade tolerance had increased, whereas those being typical for more infertile and open forest sites had decreased. There were trends towards a larger share of taxa with a more oceanic distribution.ConclusionsThe changes in the vegetation of terricolous bryophytes and lichens in the studied forests indicate nutrient enrichment and increasingly shady conditions in forests on acid soils, likely caused by nitrogen deposition and shrub layer closure.

Downstream impacts of peatland drainage on headwater stream biodiversity and ecosystem functioning

Intensive peatland drainage alters the physico-chemical status of the recipient streams, potentially leading to the loss of biodiversity and impaired ecosystem functioning. However, the extent of these changes, and particularly their impacts on downstream ecosystems, remain poorly understood. We studied the downstream effects of peatland drainage on stream biodiversity (aquatic bryophytes and macroinvertebrates) and key ecosystem processes (primary productivity, organic matter (OM) decomposition and OM standing stock). Our survey design comprised upstream (directly below drainage network) and downstream (∼300 m downstream) locations in 18 boreal headwater streams encompassing an extensive gradient of peatland drainage intensity (0–48 %). Drainage modified environmental conditions, with nutrient (TP, TN) and dissolved organic carbon (DOC) concentrations and inorganic sediment cover increasing with intensifying drainage, in both upstream and downstream sites. Species richness of both benthic macroinvertebrates and bryophytes was strongly reduced with increasing drainage intensity. Upstream and downstream sites responded in a similar manner, suggesting wide-ranging impacts of drainage on stream biodiversity. Regardless of site location, ecosystem processes were unrelated to drainage intensity. Our results confirm that intense peatland drainage not only modifies environmental conditions and biodiversity in adjoining streams, but these impacts propagate further downstream in the stream network. To prevent further degradation of drainage-impacted freshwater ecosystems, large-scale peatland restoration is needed, with prioritization of sites with the greatest potential (least drainage-induced damage) for biodiversity recovery.

Bryophyte diversity, composition and functional traits in relation to bedrock and tree species composition in close-to-nature managed forests

Bryophytes respond to a variety of environmental factors, including tree species composition and geological conditions, which are influenced by both natural and anthropogenic factors. Bryophytes growing on a variety of substrates were identified in ICP Forests monitoring plots in a wide range of close-to-nature managed forests, from lowland to high mountain areas in Slovenia. Based on data on tree layer composition (broadleaves vs. conifers) and on bedrock and soil type (calcareous vs. siliceous bedrock), all study plots were classified into five groups representing forest types. Different ordination analyses and statistical tests were used to represent differences between forest types in bryophyte composition, richness and functional traits. Almost 200 bryophyte species were identified in managed forests, with the most common being Hypnum cupressiforme, Brachytheciastrum velutinum and Polytrichum formosum. Bryophyte species composition varied considerably along the tree species composition and edaphic gradients represented by the selected forest types. Bryophyte species richness was significantly higher on calcareous bedrock than on siliceous bedrock. The higher occurrence of rocks on the ground surface may significantly increase the availability of various microhabitats for bryophytes. Bedrock had a significant influence on the functional diversity and composition of bryophytes, while tree species composition had less influence. Bedrock and tree species composition are important drivers of bryophyte species composition and diversity at taxonomic and functional trait levels. The high diversity of bryophyte species in Slovenian forests can also be attributed to close-to-nature and sustainable forest management practices that preserve favourable microclimatic conditions in forest stands and maintain diverse substrates.

Effects of Forest Restoration Age on the Species Diversity of Epiphytic Bryophyte Communities

We examined recovery of bryophyte diversity during forest restoration by the framework species method (FSM), as a component of overall biodiversity recovery—one of the defining indicators of restoration success. The epiphytic bryophyte communities in FSM trial plots (13 and 21 years since tree planting), were compared with those of old-growth forest in the upper Mae Sa Valley, northern Thailand. Bryophytes were surveyed in June 2019, on the bark of 3 framework tree species: Archidendron clypearia, Erythrina subumbrans and Sarcosperma arboreum. Fifteen species were recorded, representing 14 genera and 12 families in 3 morphological groups: acrocarpous mosses 4 species (27%), pleurocarpous mosses 5 species (33%) and leafy liverworts 6 species (40%). Within 13 years after restoration initiation, bryophyte species richness had increased to the same level as that recorded in old-growth forest. Furthermore, the bryophyte community species composition of the older restoration forest was more similar to that of natural forest than was the bryophyte community species composition of younger forest. We conclude that the FSM effectively recovers bryophyte diversity and directs the successional trajectory of the bryophyte community towards that of old growth forest within an acceptable time span. The use of bryophytes as indicators of forest restoration progress is discussed. Keywords: Conservation, Framework species method, Liverwort, Moss, Species richness

Patterns of species richness and micro-habitat occupancy among bryo-flora in mixed oak-conifer forest at Naina Peak, Nainital

We studied the bryophyte species richness and micro-habitat occupancy in a mixed oak-conifer forest (2100-2600 m) at Naina Peak, Nainital, Uttarakhand, India. The north-facing mesic site of the forest supported a greater diversity of bryophytes than that of the south-facing drier site. Altogether 146 species of bryophytes including 16 thalloid, 15 leafy liverworts, 2 hornworts and 113 mosses belonging to 48 families were documented. Amongst hepatics, leafy forms particularly the members of Frullaniaceae were found dominant over thalloid liverworts. The forest was found to support the dominant growth of acrocarpous mosses (57) followed by pleurocarpous (56). Amongst acrocarpous, the family Pottiaceae was recorded as predominant followed by the members of the pleurocarpous family Brachytheciaceae. The bryophyte species and communities associated with oak phorophytes were found to be richer and more abundant than that of the coniferous ones. Interestingly, 21 species of both liverworts and mosses turned out to be gemmiferous.

Scrub encroachment promotes biodiversity in temperate European wetlands under eutrophic conditions.

Wetlands are important habitats, often threatened by drainage, eutrophication, and suppression of grazing. In many countries, considerable resources are spent combatting scrub encroachment. Here, we hypothesize that encroachment may benefit biodiversity-especially under eutrophic conditions where asymmetric competition among plants compromises conservation targets. We studied the effects of scrub cover, nutrient levels, and soil moisture on the richness of vascular plants, bryophytes, soil fungi, and microbes in open and overgrown wetlands. We also tested the effect of encroachment, eutrophication, and soil moisture on indicators of conservation value (red-listed species, indicator species, and uniqueness). Plant and bryophyte species richness peaked at low soil fertility, whereas soil fertility promoted soil microbes. Soil fungi responded negatively to increasing soil moisture. Lidar-derived variables reflecting the degree of scrub cover had predominantly positive effects on species richness measures. Conservation value indicators had a negative relationship to soil fertility and a positive to encroachment. For plant indicator species, the negative effect of high nutrient levels was offset by encroachment, supporting our hypothesis of competitive release under shade. The positive effect of soil moisture on indicator species was strong in open habitats only. Nutrient-poor mires and meadows host many rare species and require conservation management by grazing and natural hydrology. On former agricultural lands, where restoration of infertile conditions is unfeasible, we recommend rewilding with opportunities for encroachment toward semi-open willow scrub and swamp forest, with the prospect of high species richness in bryophytes, fungi, and soil microbes and competitive release in the herb layer.

The Utility of Ground Bryophytes in the Assessment of Soil Condition in Heavy Metal-Polluted Grasslands.

Bryophytes are commonly used in biomonitoring heavy metal pollution, whereas the bioindicative value of bryophyte communities is a less known issue. The aim of the present study is to recognize the utility of the bryophyte community’s structure in the assessment of soil condition in heavy metal-polluted, dry grasslands. The study plots are examined with respect to bryophytes; vascular plants; concentrations of Zn, Pb, Cd, and As in the soil; total nitrogen and organic carbon content in the soil; and soil pH. The results show that both bryophyte species richness and composition greatly depend on soil chemical characteristics, including heavy-metal pollution levels and soil pH. Three groups of species are distinguished: (1) species sensitive to pollution growing on acidic soils, (2) nonspecific species inhabiting a wide spectrum of heavy metal-polluted sites, and (3) species preferring polluted and alkaline soils. Our study reveals a gradual replacement of the bryophyte species alongside increasing soil pollution and alkalinity. This proves that bryophytes are highly responsive to soil factors and the changes in bryophyte composition may indicate the soil condition of a certain site. Furthermore, high concentrations of heavy metals in the soil and an alkaline pH positively affect bryophyte species richness. Consequently, such sites could be considered as biodiversity hotspots for terrestrial bryophytes in post-industrial landscapes.

Long-term changes in bryophyte diversity of central European managed forests depending on site environmental features

Cryptogamic diversity is a reliable indicator of the state of forest ecosystems. In this study we analysed the variations in both bryophyte species richness overall and number of hemerophobic bryophyte species in Central European managed forests over a 20-year time span, based on data collected in 132 plots scattered across Poland. We tested differences in species richness among five temporal replicates, as well as among site types grouped based on elevation a.s.l., dominant tree species and stand age. The analyses revealed no significant trend in species richness across years. Meanwhile, species richness significantly increased along with elevation a.s.l., especially in broadleaved forests. No significant difference in species number between spruce and pine dominated stands emerged for mature stands, while there was a strong difference for young stands, with spruce forest hosting a much higher number of species. Species richness exhibited a slight, but not significant, increase over time in broadleaved forests, no significant variations in pine dominated stands and significant fluctuations in spruce dominated stands, yet without a significant trend. Out of the tested drivers, dominant tree species exhibited the strongest impact on species community composition. Number of hemerophobic and strongly hemerophobic species did not undergo significant variations across years either. The lack of bryophyte diversity trends highlighted in this study suggests Central European managed forests are in an equilibrium sate, maintained by the opposing effects of climate changes, on one side and of more sustainable forest management and pollutant deposition decline, from the other.

Epiphytic Bryophytes in an Urban Landscape: Which Factors Determine Their Distribution, Species Richness, and Diversity? A Case Study in Wroclaw, Poland.

There is still a lack of knowledge on the effect of urban environmental factors on bryophyte species distribution and richness. The goal of this study was to fill that gap. We assumed the hypothesis that the urban heat island is the most important factor affecting epiphytic bryophyte species in urban space. The survey was based on a network of 500 one hectare study plots, scattered throughout the city of Wrocław (SW Poland). A set of 27 environmental factors was assessed in the field, as well as by the collection, processing, and interpretation of satellite imagery, LiDAR scans, and climatological data. Canonical correspondence analysis was used to evaluate the significance of the effect of the studied variables on the distribution of bryophyte epiphytes. The effect of the normalized difference vegetation index on epiphytic bryophyte distribution and richness was the strongest. The effects of the urban heat island as well as the tree species diversity appeared weaker, though significant. Among the tree stands features, the supply of European ash Fraxinus excelsior and tree height appeared to be the strongest. Maintaining afforested areas rich in old tree individuals with cooler and more humid microclimates seems to be crucial to the keeping of epiphytic bryophyte species diversity in the urban landscape.

Assessing stone walls habitat quality – Which factors affect bryophytes and macrolichens on farmland stone walls in Ireland?

Stone walls are ubiquitous field boundaries used to restrict livestock movement or to separate property. Bryophytes and lichens are often the dominant vegetation in dry stone walls and are strongly affected by local microhabitat characteristics. Bryophytes and lichens related metrics can be used to define habitat quality of stone walls.The current study assessed how richness and cover of bryophytes and macrolichens in dry stone walls related to each other and how different environmental variables and farm management descriptors determined richness and cover of both groups in dry stone walls. Bryophytes and macrolichens were sampled in stone walls on sixteen farms across a management intensity gradient in Ireland.Bryophyte cover correlated positively and significantly with bryophyte richness and macrolichen cover and richness, and can thus be used to assess stone walls quality. Farm management intensity emerged as the variable most strongly related with species richness of bryophytes and cover of both groups. Altitude also emerged as a strong predictor of both groups’ richness and cover. This study provides a novel perspective on stone wall habitat quality and results indicate that by promoting extensive farming it is possible to increase stone walls quality.

Determinants of bryophyte assemblages in traditionally managed grasslands of the Carpathian Mts

Questions Although bryophytes play an important role in grassland ecosystems, environmental factors that drive bryophyte assemblages were rarely studied, especially in low-intensity traditional grasslands. Therefore, using fine-scale data on bryophyte assemblages in traditionally managed secondary grasslands, we studied the relative importance of several sets of environmental drivers (related to topography, soil properties, landscape, and management) of: (i) taxonomic and functional compositions; and (ii) cover and species richness of bryophyte communities. Location Central and Eastern Europe, Carpathian Mountains, 15 sites with preserved traditional management practices distributed in Romania (six sites), Ukraine (four), Slovakia (two), Austria (one), Hungary (one) and Poland (one). Methods Fine-scale data on soil, topography, and vegetation structure as well as on bryophyte assemblages (taxonomic and functional composition, cover, species richness) were collected in 10-m2 plots. We used stratified random sampling to select six 10-m2 plots of traditionally managed grasslands in each of the 15 sites (n = 90). Climatic and landscape variables were extracted from online databases and available maps. Detailed data on present and historical land use were obtained from parcel owners. To assess the effect of drivers on bryophyte taxonomic and functional composition we applied canonical correspondence analysis (CCA) and redundancy analysis (RDA), respectively; for bryophyte species richness and bryophyte cover we used GLMMs. Forward stepwise variable selection procedure was used to find best set of drivers for each of the analyses. Results Topographic (microrelief and solar radiation) and soil-related factors (cover of stones and rocks, soil depth, moisture), as well as the cover of the herb layer and bare soil were the strongest drivers of bryophyte taxonomic composition. Among the management- and landscape-related variables only mean size of grassland parcels within 1-km2 plot surroundings and grazing by horse were included in the CCA model explaining in total 25.9% of variation in species composition. Bryophyte functional composition was explained by a similar set of variables (RDA explained 27.3% of variation in functional composition) including additionally cover of gravel and burning. Solar radiation (negative effect) and management stability (positive effect) were the strongest drivers of bryophyte cover. Management stability had the strongest effect (positive) on bryophyte species richness, followed by grassland age (negative) and microrelief (positive). Conclusions Taxonomic and functional composition of bryophyte assemblages as well as bryophyte cover in traditional grasslands were determined mainly by variables related to moisture and light availability. Management-related factors seem to be at least as equally important as abiotic factors for bryophyte species richness and cover. Our results suggest that for maintaining bryophyte-rich grasslands one should also consider stability of grassland management, that is, temporal continuity and regularity of management practices applied.

Nibble, cut, stomp and burn: Biodiversity effects of disturbances in fen grassland

AbstractAimsWe assessed biodiversity effects of disturbance in meadows and rich fens. We hypothesized that disturbances and their timing affect plant and bryophyte species richness and other indicators of conservation success. More specifically, we expected conservation status to improve with disturbances that mimic natural grazing processes, that is, that extensive year‐round grazing with trampling had a more positive effect than intensive summer grazing or mowing.LocationKastbjerg wetlands, Jutland, Denmark.MethodsIn a three‐year field experiment, we applied trampling, season‐specific defoliation with biomass removal and burning in a randomized design in nine wetland sites. We recorded species richness and community composition. Bayesian generalized linear mixed‐effects models were built with treatment as fixed effect, site as random effect and species richness or species composition as responses. Leaf N and P, and soil moisture were included as covariables. Further, a quadratic discriminant analysis (QDA) was applied to test for discrimination between treatments based on a set of biodiversity indicators.ResultsEnvironmental and biotic differences among sites were considerable and significant indicating a considerable effect of historical contingency (local species pool). We found only minor and mostly insignificant effects of disturbance on vegetation. However, a QDA revealed significant differences among treatments based on five indicators for conservation status. Simulated grazing and trampling were generally associated with higher vascular plant richness, bryophyte richness, number of indicator species and stress‐tolerant species and decreasing abundance of competitive species.ConclusionWe found small, but positive effects of disturbance on biodiversity indicators of wetland vegetation after three years of experimental treatments. Initial site differences explained most variation, indicating strong historical contingency. Our results support the need for restoration of disturbances in fens and meadows, and the importance of prioritizing areas with near‐natural biotas.

Effects of stand structure and ungulates on understory vegetation in managed and unmanaged forests.

Conventional conservation policies in Europe notably rely on the passive restoration of natural forest dynamics by setting aside forest areas to preserve forest biodiversity. However, since forest reserves cover only a small proportion of the territory, conservation policies also require complementary conservation efforts in managed forests in order to achieve the biodiversity targets set up in the Convention on Biological Diversity. Conservation measures also raise the question of large herbivore management in and around set-asides, particularly regarding their impact on understory vegetation. Although many studies have separately analyzed the effects of forest management, management abandonment, and ungulate pressure on forest biodiversity, their joint effects have rarely been studied in a correlative framework. We studied 212 plots located in 15 strict forest reserves paired with adjacent managed forests in European France. We applied structural equation models to test the effects of management abandonment, stand structure, and ungulate pressure on the abundance, species richness, and diversity of herbaceous vascular plants and terricolous bryophytes. We showed that stand structure indices and plot-level browsing pressure had direct and opposite effects on herbaceous vascular plant species diversity; these effects were linked with the light tolerance of the different species groups. Increasing canopy cover had an overall negative effect on herbaceous vascular plant abundance and species diversity. The effect was two to three times greater in magnitude than the positive effects of browsing pressure on herbaceous plants diversity. On the other hand, a high stand density index had a positive effect on the species richness and diversity of bryophytes, while browsing had no effect. Forest management abandonment had few direct effects on understory plant communities, and mainly indirectly affected herbaceous vascular plant and bryophyte abundance and species richness and diversity through changes in vertical stand structure. Our results show that conservation biologists should rely on foresters and hunters to lead the preservation of understory vegetation communities in managed forests since, respectively, they manipulate stand structure and regulate ungulate pressure. Their management actions should be adapted to the taxa at stake, since bryophytes and vascular plants respond differently to stand and ungulate factors.

Plant biodiversity declines with increasing coffee yield in Ethiopia's coffee agroforests

Abstract Tropical agroforestry systems provide farmers with resources for their livelihoods, but are also well‐recognized as refuges for biodiversity. However, the relationship between yield and biodiversity might be negative in these systems, reflecting a potential trade‐off between managing for increased yield or biodiversity. The potential for synergies will depend partly on the shape of the biodiversity–yield relationship, where a concave relationship suggests a faster decline in biodiversity with increasing yields than a linear or convex shape. We studied the relationship between biodiversity (plant species richness and composition) and coffee yield along a gradient of management in south‐western Ethiopia, coffee's native range. We inventoried species richness and community composition of woody plants, herbaceous plants and bryophytes at 60 sites. We also measured coffee management‐related variables and assessed coffee yield for 3 consecutive years at each site. Species richness of woody plants had a concave relationship with coffee yield, that is, tree richness declined fast initially before levelling out at higher yields, whereas there was no relationship between coffee yield and species richness of herbaceous plants or bryophytes. Species composition of woody plants, herbaceous plants and bryophytes all had a concave relationship with coffee yield. From a methodological perspective, we found that multi‐year data on yield were necessary to reliably assess the relationship between biodiversity and yield, and that the number of coffee shrubs or coffee dominance were poor proxies for yield when trying to capture the biodiversity–yield relationship. Synthesis and applications. The concave relationship between biodiversity components (species richness and composition) and yield suggests that there is a strong conflict between the goals of increasing production and conserving biodiversity. However, it is important to recognize that this pattern is largely driven by the very low‐yielding sites in natural forests. Here, even minor intensification of coffee management seems to rapidly erode biodiversity. Along the rest of the productivity gradient, there was generally no negative relationship between yield and biodiversity, implying opportunities for developing strategies for increasing yields without biodiversity loss.

Can high-resolution topography and forest canopy structure substitute microclimate measurements? Bryophytes say no

Increasingly available high-resolution digital elevation models (DEMs) facilitate the use of fine-scale topographic variables as proxies for microclimatic effects not captured by the coarse-grained macroclimate datasets. Species distributions and community assembly rules are, however directly shaped by microclimate and not by topography. DEM-derived topography, sometimes combined with vegetation structure, is thus widely used as a proxy for microclimatic effects in ecological research and conservation applications. However, the suitability of such a strategy has not been evaluated against in situ measured microclimate and species composition. Because bryophytes are highly sensitive to microclimate, they are ideal model organisms for such evaluation.To provide this much needed evaluation, we simultaneously recorded bryophyte species composition, microclimate, and forest vegetation structure at 218 sampling sites distributed across topographically complex sandstone landscape. Using a LiDAR-based DEM with a 1 m resolution, we calculated eleven topographic variables serving as a topographic proxy for microclimate. To characterize vegetation structure, we used hemispherical photographs and LiDAR canopy height models. Finally, we calculated eleven microclimatic variables from a continuous two-year time- series of air and soil temperature and soil moisture. To evaluate topography and vegetation structure as substitutes for the ecological effect of measured microclimate, we partitioned the variation in bryophyte species composition and richness explained by microclimate, topography, and vegetation structure.In situ measured microclimate was clearly the most important driver of bryophyte assemblages in temperate coniferous forests. The most bryophyte-relevant variables were growing degree days, maximum air temperature, and mean soil moisture. Our results thus showed that topographic variables, even when derived from high-resolution LiDAR data and combined with in situ sampled vegetation structure, cannot fully substitute effects of in situ measured microclimate on forest bryophytes.