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Brief introduction: What are microclimates and why are they important?: Microclimate science has developed into a global discipline. Microclimate science is increasingly used to understand and mitigate climate and biodiversity shifts. Here, we provide an overview of the current status of microclimate ecology and biogeography in terrestrial ecosystems, and where this field is heading next. Microclimate investigations in ecology and biogeography: We highlight the latest research on interactions between microclimates and organisms, including how microclimates influence individuals, and through them populations, communities and entire ecosystems and their processes. We also briefly discuss recent research on how organisms shape microclimates from the tropics to the poles. Microclimate applications in ecosystem management: Microclimates are also important in ecosystem management under climate change. We showcase new research in microclimate management with examples from biodiversity conservation, forestry and urban ecology. We discuss the importance of microrefugia in conservation and how to promote microclimate heterogeneity. Methods for microclimate science: We showcase the recent advances in data acquisition, such as novel field sensors and remote sensing methods. We discuss microclimate modelling, mapping and data processing, including accessibility of modelling tools, advantages of mechanistic and statistical modelling and solutions for computational challenges that have pushed the state-of-the-art of the field. What's next?: We identify major knowledge gaps that need to be filled for further advancing microclimate investigations, applications and methods. These gaps include spatiotemporal scaling of microclimate data, mismatches between macroclimate and microclimate in predicting responses of organisms to climate change, and the need for more evidence on the outcomes of microclimate management.

Aim: The amount of forest edges is increasing globally due to forest fragmentation and land-use changes. However, edge effects on the soil seed bank of temperate forests are still poorly understood. Here, we assessed edge effects at contrasting spatial scales across Europe and quantified the extent to which edges can preserve the seeds of forest specialist plants. Location: Temperate European deciduous forests along a 2,300-km latitudinal gradient. Time period: 2018-2021. Major taxa studied: Vascular plants. Methods: Through a greenhouse germination experiment, we studied how edge effects alter the density, diversity, composition and functionality of forest soil seed banks in 90 plots along different latitudes, elevations and forest management types. We also assessed which environmental conditions drive the seed bank responses at the forest edge versus interior and looked at the relationship between the seed bank and the herb layer species richness. Results: Overall, 10,108 seedlings of 250 species emerged from the soil seed bank. Seed density and species richness of generalists (species not only associated with forests) were higher at edges compared to interiors, with a negative influence of C : N ratio and litter quality. Conversely, forest specialist species richness did not decline from the interior to the edge. Also, edges were compositionally, but not functionally, different from interiors. The correlation between the seed bank and the herb layer species richness was positive and affected by microclimate. Main conclusions: Our results underpin how edge effects shape species diversity and composition of soil seed banks in ancient forests, especially increasing the proportion of generalist species and thus potentially favouring a shift in community composition. However, the presence of many forest specialists suggests that soil seed banks still play a key role in understorey species persistence and could support the resilience of our fragmented forests.

Forest canopies buffer macroclimatic temperature fluctuations. However, we do not know if and how the capacity of canopies to buffer understorey temperature will change with accelerating climate change. Here we map the difference (offset) between temperatures inside and outside forests in the recent past and project these into the future in boreal, temperate and tropical forests. Using linear mixed-effect models, we combined a global database of 714 paired time series of temperatures (mean, minimum and maximum) measured inside forests vs. in nearby open habitats with maps of macroclimate, topography and forest cover to hindcast past (1970–2000) and to project future (2060–2080) temperature differences between free-air temperatures and sub-canopy microclimates. For all tested future climate scenarios, we project that the difference between maximum temperatures inside and outside forests across the globe will increase (i.e. result in stronger cooling in forests), on average during 2060–2080, by 0.27 ± 0.16 °C (RCP2.6) and 0.60 ± 0.14 °C (RCP8.5) due to macroclimate changes. This suggests that extremely hot temperatures under forest canopies will, on average, warm less than outside forests as macroclimate warms. This knowledge is of utmost importance as it suggests that forest microclimates will warm at a slower rate than non-forested areas, assuming that forest cover is maintained. Species adapted to colder growing conditions may thus find shelter and survive longer than anticipated at a given forest site. This highlights the potential role of forests as a whole as microrefugia for biodiversity under future climate change.

Forests harbour large spatiotemporal heterogeneity in canopy structure. This variation drives the microclimate and light availability at the forest floor. So far, we do not know how light availability and sub-canopy temperature interactively mediate the impact of macroclimate warming on understorey communities. We therefore assessed the functional response of understorey plant communities to warming and light addition in a full factorial experiment installed in temperate deciduous forests across Europe along natural microclimate, light and macroclimate gradients. Furthermore, we related these functional responses to the species’ life-history syndromes and thermal niches. We found no significant community responses to the warming treatment. The light treatment, however, had a stronger impact on communities, mainly due to responses by fast-colonizing generalists and not by slow-colonizing forest specialists. The forest structure strongly mediated the response to light addition and also had a clear impact on functional traits and total plant cover. The effects of short-term experimental warming were small and suggest a time-lag in the response of understorey species to climate change. Canopy disturbance, for instance due to drought, pests or logging, has a strong and immediate impact and particularly favours generalists in the understorey in structurally complex forests.

Aim: The amount of forest edges is increasing globally due to forest fragmentation and land-use changes. However, edge effects on the soil seed bank of temperate forests are still poorly understood. Here, we assessed edge effects at contrasting spatial scales across Europe and quantified the extent to which edges can preserve the seeds of forest specialist plants. Location: Temperate European deciduous forests along a 2,300-km latitudinal gradient. Time period: 2018–2021. Major taxa studied: Vascular plants. Methods: Through a greenhouse germination experiment, we studied how edge effects alter the density, diversity, composition and functionality of forest soil seed banks in 90 plots along different latitudes, elevations and forest management types. We also assessed which environmental conditions drive the seed bank responses at the forest edge versus interior and looked at the relationship between the seed bank and the herb layer species richness. Results: Overall, 10,108 seedlings of 250 species emerged from the soil seed bank. Seed density and species richness of generalists (species not only associated with forests) were higher at edges compared to interiors, with a negative influence of C : N ratio and litter quality. Conversely, forest specialist species richness did not decline from the interior to the edge. Also, edges were compositionally, but not functionally, different from interiors. The correlation between the seed bank and the herb layer species richness was positive and affected by microclimate. Main conclusions: Our results underpin how edge effects shape species diversity and composition of soil seed banks in ancient forests, especially increasing the proportion of generalist species and thus potentially favouring a shift in community composition. However, the presence of many forest specialists suggests that soil seed banks still play a key role in understorey species persistence and could support the resilience of our fragmented forests.

Aim: Variation in plant defence traits has been frequently assessed along large-scale macroclimatic clines. In contrast, local-scale changes in the environment have recently been proposed to also modulate plant defence traits. Yet, the relative importance of drivers at both scales has never been tested. We aimed to quantify the relative importance of environmental drivers inherent to large and small spatial scales on the physical and chemical defence and tolerance to herbivory in understorey plant species of deciduous forests of Europe. Location: Deciduous forests in Europe. Time period: Present. Major taxa studied: Forest understorey plants. Methods: We sampled four typical ancient forest herbs (Anemone nemorosa, Oxalis acetosella, Deschampsia cespitosa, Milium effusum) along small and large spatial scale gradients (those driven by latitude, elevation, forest management and distance to the forest edge), and analysed a suite of nine constitutively expressed traits associated with overall resistance to herbivory, and their multivariate response to environmental clines. Results: Although our study included a large gradient in macroclimate, we found variation in the local environment at small spatial scales (i.e. soil nutrient concentration and forest structural complexity) to be more important in predicting plant resistance to herbivory. Main conclusions: In addition to macroclimatic conditions, subtle differences in forest microclimate and soil characteristics also played a major role in modulating plant defence phenotypes. These findings highlight the importance of the local habitat structure and environmental conditions in modulating plant resistance to herbivory.

Forest biodiversity world‐wide is affected by climate change, habitat loss and fragmentation, and today 20% of the forest area is located within 100 m of a forest edge. Still, forest edges harbour a substantial amount of terrestrial biodiversity, especially in the understorey. The functional and phylogenetic diversity of forest edges have never been studied simultaneously at a continental scale, in spite of their importance for the forests' functioning and for communities' resilience to future change. We assessed nine metrics of taxonomic, phylogenetic and functional diversity of understorey plant communities in 225 plots spread along edge‐to‐interior gradients in deciduous forests across Europe. We then derived the relative effects and importance of edaphic, stand and landscape conditions on the diversity metrics. Here, we show that taxonomic, phylogenetic and functional diversity metrics respond differently to environmental conditions. We report an increase in functional diversity in plots with stronger microclimatic buffering, in spite of their lower taxonomic species richness. Additionally, we found increased taxonomic species richness at the forest edge, but in forests with intermediate and high openness, these communities had decreased phylogenetic diversity. Functional and phylogenetic diversity revealed complementary and important insights in community assembly mechanisms. Several environmental filters were identified as potential drivers of the patterns, such as a colder macroclimate and less buffered microclimate for functional diversity. For phylogenetic diversity, edaphic conditions were more important. Interestingly, plots with lower soil pH had decreased taxonomic species richness, but led to increased phylogenetic diversity, challenging the phylogenetic niche conservatism concept. Synthesis. Taxonomic, phylogenetic and functional diversity of understorey communities in forest edges respond differently to environmental conditions, providing insight int

Global forest cover is heavily fragmented. Due to high edge-to-surface ratios in small forest patches, a large proportion of forests is affected by edge influences involving steep microclimatic gradients. Although forest edges are important ecotones and account for 20% of the global forested area, it remains unclear how biotic and abiotic drivers affect forest edge microclimates at the continental scale. Here we report soil and air temperatures measured in 225 deciduous forest plots across Europe for two years. Forest stands were situated along a latitudinal gradient and subject to a varying vegetation structure as quantified by terrestrial laser scanning. In summer, the average offset of air and soil temperatures in forest edges compared to temperatures outside the forest amounted to -2.8 °C and -2.3 °C, respectively. Edge-to-interior summer temperature gradients were affected by the macroclimate and edge structure. From the edge onwards, larger offsets were observed in dense forest edges and in warmer, southern regions. In open forests and northern Europe, altered microclimatic conditions extended deeper into the forest and gradients were steeper. Canopy closure and plant area index were important drivers of summer offsets in edges, whereas in winter also the forest-floor biomass played a key role. Using high-resolution maps, we estimated that approximately 10% of the European broadleaved forests would be affected by altered temperature regimes. Gradual transition zones between forest and adjacent lands are valuable habitat types for edge species. However, if cool and moist forest interiors are desired, then (i) dense and complex forest edges, (ii) an undisturbed forested buffer zone of at least 12.5 m deep and (iii) trees with a high shade casting ability could all contribute to an increased offset. These findings provide important guidelines to mitigate edge influences, to protect typical forest microclimates and to adapt forest management to climate change.

Forest biodiversity world-wide is affected by climate change, habitat loss and fragmentation, and today 20% of the forest area is located within 100 m of a forest edge. Still, forest edges harbour a substantial amount of terrestrial biodiversity, especially in the understorey. The functional and phylogenetic diversity of forest edges have never been studied simultaneously at a continental scale, in spite of their importance for the forests' functioning and for communities' resilience to future change. We assessed nine metrics of taxonomic, phylogenetic and functional diversity of understorey plant communities in 225 plots spread along edge-to-interior gradients in deciduous forests across Europe. We then derived the relative effects and importance of edaphic, stand and landscape conditions on the diversity metrics. Here, we show that taxonomic, phylogenetic and functional diversity metrics respond differently to environmental conditions. We report an increase in functional diversity in plots with stronger microclimatic buffering, in spite of their lower taxonomic species richness. Additionally, we found increased taxonomic species richness at the forest edge, but in forests with intermediate and high openness, these communities had decreased phylogenetic diversity. Functional and phylogenetic diversity revealed complementary and important insights in community assembly mechanisms. Several environmental filters were identified as potential drivers of the patterns, such as a colder macroclimate and less buffered microclimate for functional diversity. For phylogenetic diversity, edaphic conditions were more important. Interestingly, plots with lower soil pH had decreased taxonomic species richness, but led to increased phylogenetic diversity, challenging the phylogenetic niche conservatism concept. Synthesis. Taxonomic, phylogenetic and functional diversity of understorey communities in forest edges respond differently to environmental conditions, providing insight int

This paper presents all current knowledge on the biology of the invasive therophyte Impatiens glandulifera Royle (Himalayan Balsam), and covers aspects of taxonomy, morphology, distribution, habitat requirements, ecology, life cycle, genetics, history of invasive spread, ecological impact and management. Although a few review papers have been published on this species in previous decades, a great deal of insights have been gained in the last three decades, owing to the species & rsquo; notorious reputation as one of the most problematic invasive species in Europe. This study consequently focusses on this novel information, with a particular focus on information from Central Europe., Funding Agencies|Research Foundation - Flanders (FWO) through funding of the scientific research network FLEURFWO [1202817N, ASP035-19, G0H1517N]; European Research Council (ERC) under the European UnionEuropean Research Council (ERC) [FORMICA 757833]

This account presents information on all aspects of the biology ofPoa nemoralisL. (Wood Meadow-grass) that are relevant to understanding its ecological characteristics and behaviour. The main topics are presented within the standard framework of theBiological Flora of the British Isles: distribution, habitat, communities, responses to biotic factors, responses to environment, structure and physiology, phenology, floral and seed characters, herbivores and disease, history, and conservation. The grassPoa nemoralisis widespread and frequent to locally common across the British Isles, except for western and central Ireland, and northern Scotland. In both its native Eurasian range and introduced ranges in, for example, the Americas, its main habitat comprises temperate (mixed) deciduous woodland. The species finds important secondary habitats in hedgerows, as well as in non-woodland vegetation such as on cliffs, screes and walls or sporadically in grassland and heathland. Although not always taxonomically or morphologically distinct units, the species is suspected to comprise many cytological races and hybrid polyploid populations with variable morphology. Morphological variation amongP. nemoralispopulations may also be a sign of local environmental adaptation or a result of introgressive hybridization with other, morphologically variable members ofPoasectionStenopoasuch asP. glauca,P. compressaorP. pratensis. Poa nemoralisis a small-statured, loosely caespitose grass, with populations ranging from a few individual tufts to those visually defining the aspect of the herbaceous understorey. The species tolerates moderate to deep shade on the forest floor, yet it tends to forage for available light, occurring more and growing taller in canopy gaps, forest edges and hedgerows. The amount of light is central to its survival and reproductive ecology, being important for flower induction, seed production and seed germination. The species produces large quantities of small, ligh, Funding Agencies|Svenska Forskningsradet FORMAS Future Research Leaders [2018-00961]; European Research CouncilEuropean Research Council (ERC) [FORMICA 757833]

Brief introduction: What are microclimates and why are they important?: Microclimate science has developed into a global discipline. Microclimate science is increasingly used to understand and mitigate climate and biodiversity shifts. Here, we provide an overview of the current status of microclimate ecology and biogeography in terrestrial ecosystems, and where this field is heading next. Microclimate investigations in ecology and biogeography: We highlight the latest research on interactions between microclimates and organisms, including how microclimates influence individuals, and through them populations, communities and entire ecosystems and their processes. We also briefly discuss recent research on how organisms shape microclimates from the tropics to the poles. Microclimate applications in ecosystem management: Microclimates are also important in ecosystem management under climate change. We showcase new research in microclimate management with examples from biodiversity conservation, forestry and urban ecology. We discuss the importance of microrefugia in conservation and how to promote microclimate heterogeneity. Methods for microclimate science: We showcase the recent advances in data acquisition, such as novel field sensors and remote sensing methods. We discuss microclimate modelling, mapping and data processing, including accessibility of modelling tools, advantages of mechanistic and statistical modelling and solutions for computational challenges that have pushed the state‐of‐the‐art of the field. What's next?: We identify major knowledge gaps that need to be filled for further advancing microclimate investigations, applications and methods. These gaps include spatiotemporal scaling of microclimate data, mismatches between macroclimate and microclimate in predicting responses of organisms to climate change, and the need for more evidence on the outcomes of microclimate manageme