Aim: European grassland communities are highly diverse, but patterns and drivers of their continental‐scale diversity remain elusive. This study analyses taxonomic and functional richness in European grasslands along continental‐scale temperature and precipitation gradients.Location: Europe.Methods: We quantified functional and taxonomic richness of 55,748 vegetation plots. Six plant traits, related to resource acquisition and conservation, were analysed to describe plant community functional composition. Using a null‐model approach we derived functional richness effect sizes that indicate higher or lower diversity than expected given the taxonomic richness. We assessed the variation in absolute functional and taxonomic richness and in functional richness effect sizes along gradients of minimum temperature, temperature range, annual precipitation, and precipitation seasonality using a multiple general additive modelling approach.Results: Functional and taxonomic richness was high at intermediate minimum temperatures and wide temperature ranges. Functional and taxonomic richness was low in correspondence with low minimum temperatures or narrow temperature ranges. Functional richness increased and taxonomic richness decreased at higher minimum temperatures and wide annual temperature ranges. Both functional and taxonomic richness decreased with increasing precipitation seasonality and showed a small increase at intermediate annual precipitation. Overall, effect sizes of functional richness were small. However, effect sizes indicated trait divergence at extremely low minimum temperatures and at low annual precipitation with extreme precipitation seasonality.Conclusions: Functional and taxonomic richness of European grassland communities vary considerably over temperature and precipitation gradients. Overall, they follow similar patterns over the climate gradients, except at high minimum temperatures and wide temperature ranges, where functional richness increases and taxonomic richness decreases. This contrasting pattern may trigger new ideas for studies that target specific hypotheses focused on community assembly processes. And though effect sizes were small, they indicate that it may be important to consider climate seasonality in plant diversity studies.

This account presents information on all aspects of the biology of Fritillaria meleagris L. (Snake's Head Fritillary). The main topics are presented within the standard framework of the Biological Flora of Britain and Ireland: distribution, habitat, communities, responses to biotic factors, responses to environment, structure and physiology, phenology, floral and seed characters, herbivores and disease, history, and conservation. Fritillaria meleagris is a perennial spring bulb that grows in wet mesotrophic meadows and wet openings in woodlands. In Britain, it is localised to floodplain meadows but occurs as an intentional introduction in a range of habitats. There are several large populations on the floodplains of the River Thames and its tributaries in Wiltshire, Berkshire and Oxfordshire. Fritillaria meleagris occurs on mesotrophic alluvium soils often overlaying calcareous gravel with a relatively wide pH range. It favours a high ground water table during winter months and spring followed by good drainage of the soil throughout the summer. Fritillaria meleagris plants regularly experience prolonged dormancy. From 30% to 99% of plants in a population can remain below‐ground for more than a year. Fritillaria meleagris produces nectar and is mainly pollinated in April by bumblebee queens in England. Other pollinators include insects of the orders Hymenoptera, Diptera and Lepidoptera, particularly bumblebees, hoverflies and butterflies. The release of the seeds from the pod in May–June can take a month. Seeds require warm and cold treatments for the embryo to fully form. Air pockets aid seed flotation on the surface of flood water for up to a month. The seeds of Fritillaria meleagris do not form a seed bank, germinating either during flotation or on bare ground. Fritillaria meleagris declined in Britain during the 20th century due to agricultural improvement and ploughing of floodplain grasslands. In all, 20 or so remaining populations survive in ancient hay meadows. Several of its British locations receive statutory protection as designated sites. However, recent work suggests that F. meleagris was probably introduced to Britain as an ornamental, and the level of protection it receives is therefore likely to change.

We assessed the potential for using optical functional types as effective markers to monitor changes in vegetation in floodplain meadows associated with changes in their local environment. Floodplain meadows are challenging ecosystems for monitoring and conservation because of their highly biodiverse nature. Our aim was to understand and explain spectral differences among key members of floodplain meadows and also characterize differences with respect to functional traits. The study was conducted on a typical floodplain meadow in UK (MG4-type, mesotrophic grassland type 4, according to British National Vegetation Classification). We compared two approaches to characterize floodplain communities using field spectroscopy. The first approach was sub-community based, in which we collected spectral signatures for species groupings indicating two distinct eco-hydrological conditions (dry and wet soil indicator species). The other approach was “species-specific”, in which we focused on the spectral reflectance of three key species found on the meadow. One herb species is a typical member of the MG4 floodplain meadow community, while the other two species, sedge and rush, represent wetland vegetation. We also monitored vegetation biophysical and functional properties as well as soil nutrients and ground water levels. We found that the vegetation classes representing meadow sub-communities could not be spectrally distinguished from each other, whereas the individual herb species was found to have a distinctly different spectral signature from the sedge and rush species. The spectral differences between these three species could be explained by their observed differences in plant biophysical parameters, as corroborated through radiative transfer model simulations. These parameters, such as leaf area index, leaf dry matter content, leaf water content, and specific leaf area, along with other functional parameters, such as maximum carboxylation capacity and leaf nitrogen content, also helped explain the species’ differences in functional dynamics. Groundwater level and soil nitrogen availability, which are important factors governing plant nutrient status, were also found to be significantly different for the herb/wetland species’ locations. The study concludes that spectrally distinguishable species, typical for a highly biodiverse site such as a floodplain meadow, could potentially be used as target species to monitor vegetation dynamics under changing environmental conditions.

Fritillaria meleagris L. is a rare species mainly associated with floodplain forests and meadows. Conservation of populations of this species needs to consider a key aspect of its life history – prolonged dormancy (PD). In F. meleagris, this was observed during 8-years monitoring of individual plants on the protected ancient Lugg Meadow in the UK. One-year PD was most frequently observed in the population, followed by 2-year PD. Seven-year dormancy was the longest recorded. Twenty two percent of plants didn’t display PD during the observation period. Large variability in the patterns of individual plants submerging and re-emerging from dormancy in different years, suggested individual genetic heterogeneity as the main factor driving PD of the species. Three morphological states were identified in dormant plants of F. meleagris including a false dormancy in individuals which carried on growing below ground. Patterns of PD in rare species need to be studied on individually monitored plants and applied to models of population dynamics for species conservation purposes