Soil seed bank responses to edge effects in temperate European 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

Trait data 2019 and 2020 experimental microclimate warming and light addition across Europe (FORMICA). Data used for the analysis in 'Forest understorey communities respond strongly to light in interaction with forest structure but not to microclimate warming' (De Pauw et al., New Phytologist, 2021)

This dataset contains functional trait data (plant height and specific leaf area) measured on individuals in understorey plant communities subjected to experimental microclimate warming and lighting at three sites across Europe. Measurements were done in 2019 and 2020. The second tab of the excel contains metadata explaining the columns.Data used for the analysis in 'Forest understorey communities respond strongly to light in interaction with forest structure but not to microclimate warming' (De Pauw et al., New Phytologist, 2021)<br

Negative effects of winter and spring warming on the regeneration of forest spring geophytes

The climate is changing rapidly, provoking species to shift their ranges poleward and upslope. We currently lack a mechanistic understanding of the effect of warmer temperatures on plants, especially for seasonally distinct patterns. Spring geophytes are emblematic forest plants that have a short aboveground lifecycle in the first half of the year and are thus particularly sensitive to winter and spring warming. We set up a warming experiment with separate and combined winter and spring warming on seedlings of three European spring geophytes: Anemone nemorosa, Hyacinthoides non-scripta and Ornithogalum pyrenaicum. Seedling emergence and plant height were recorded at the end of winter and spring treatment, when also biomass of the root, shoot and storage organ was determined. We found negative effects of combined winter and spring warming on seedling emergence. The weight of the storage organ proved to be the best indicator of seedling performance and was negatively affected by separate winter warming in Anemone and by spring warming in Hyacinthoides. Successful seedling emergence was jeopardized by the absence of a cold period, while seedling performance seemed to be negatively influenced directly by higher temperatures through a phenological shift. Our findings confirm that warmer winter and spring temperatures could hamper regeneration of spring geophytes

Species distribution models and a 60-year-old transplant experiment reveal inhibited forest plant range shifts under climate change

Aim Climate change causes species to shift their distributions. Individual species, however, greatly vary in their capacity to track the macroclimatic temperature increase due to differences in demography and dispersal. To better predict range shifts to climate change we need a complementary integration of long-term empirical data and predictive modelling. Location Belgium and North-West Europe. Taxon Hyacinthoides non-scripta, forest understorey plants. Methods Complementing species distribution models with demographic data from an exceptional 60-year-old over-the-range-edge transplant experiment measured not less than 45 and 60 years after installation, we evaluated the long-term consequences of climate change on one of the most emblematic but also among the slowest colonizing plant species of European forests, bluebell Hyacinthoides non-scripta. Results We found bluebell able to establish viable populations beyond its natural range. These results were confirmed by the SDM, showing that bluebell's potential range is considerably larger than its current range. Colonization rates of only 2 m century(-1) were observed in the transplanted populations. Beyond bluebell's current range, we observed decreasing trends in population growth rates over the past 15 years. By the end of the 21st century, substantial decreases in the southern parts of bluebell's range were predicted. Main conclusions Based on empirical and modelling results, we expect serious population declines in large parts of its current natural distribution of bluebell. Although the species is able to establish viable populations beyond the natural range edge, slow demography and local colonization rates four orders of magnitude lower than the velocity of climate change make fast enough range shifts virtually impossible in this species

MIRRA : a modular and cost-effective microclimate monitoring system for real-time remote applications

Monitoring climate change, and its impacts on ecological, agricultural, and other societal systems, is often based on temperature data derived from official weather stations. Yet, these data do not capture most microclimates, influenced by soil, vegetation and topography, operating at spatial scales relevant to the majority of organisms on Earth. Detecting and attributing climate change impacts with confidence and certainty will only be possible by a better quantification of temperature changes in forests, croplands, mountains, shrublands, and other remote habitats. There is an urgent need for a novel, miniature and simple device filling the gap between low-cost devices with manual data download (no instantaneous data) and high-end, expensive weather stations with real-time data access. Here, we develop an integrative real-time monitoring system for microclimate measurements: MIRRA (Microclimate Instrument for Real-time Remote Applications) to tackle this problem. The goal of this platform is the design of a miniature and simple instrument for near instantaneous, long-term and remote measurements of microclimates. To that end, we optimised power consumption and transfer data using a cellular uplink. MIRRA is modular, enabling the use of different sensors (e.g., air and soil temperature, soil moisture and radiation) depending upon the application, and uses an innovative node system highly suitable for remote locations. Data from separate sensor modules are wirelessly sent to a gateway, thus avoiding the drawbacks of cables. With this sensor technology for the long-term, low-cost, real-time and remote sensing of microclimates, we lay the foundation and open a wide range of possibilities to map microclimates in different ecosystems, feeding a next generation of models. MIRRA is, however, not limited to microclimate monitoring thanks to its modular and wireless design. Within limits, it is suitable or any application requiring real-time data logging of power-efficient sensors over long periods of time. We compare the performance of this system to a reference system in real-world conditions in the field, indicating excellent correlation with data collected by established data loggers. This proof-of-concept forms an important foundation to creating the next version of MIRRA, fit for large scale deployment and possible commercialisation. In conclusion, we developed a novel wireless cost-effective sensor system for microclimates