Plant dependence on fungal carbon (mycoheterotrophy) evolved repeatedly. In orchids, it is connected with a mycorrhizal shift from rhizoctonia to ectomycorrhizal fungi and a high natural (13)C and (15)N abundance. Some green relatives of mycoheterotrophic species show identical trends, but most of these remain unstudied, blurring our understanding of evolution to mycoheterotrophy. We analysed mycorrhizal associations and (13)C and (15)N biomass content in two green species, Neottia ovata and N. cordata (tribe Neottieae), from a genus comprising green and nongreen (mycoheterotrophic) species. Our study covered 41 European sites, including different meadow and forest habitats and orchid developmental stages. Fungal ITS barcoding and electron microscopy showed that both Neottia species associated mainly with nonectomycorrhizal Sebacinales Clade B, a group of rhizoctonia symbionts of green orchids, regardless of the habitat or growth stage. Few additional rhizoctonias from Ceratobasidiaceae and Tulasnellaceae, and ectomycorrhizal fungi were detected. Isotope abundances did not detect carbon gain from the ectomycorrhizal fungi, suggesting a usual nutrition of rhizoctonia-associated green orchids. Considering associations of related partially or fully mycoheterotrophic species such as Neottia camtschatea or N. nidus-avis with ectomycorrhizal Sebacinales Clade A, we propose that the genus Neottia displays a mycorrhizal preference for Sebacinales and that the association with nonectomycorrhizal Sebacinales Clade B is likely ancestral. Such a change in preference for mycorrhizal associates differing in ecology within the same fungal taxon is rare among orchids. Moreover, the existence of rhizoctonia-associated Neottia spp. challenges the shift to ectomycorrhizal fungi as an ancestral pre-adaptation to mycoheterotrophy in the whole Neottieae.
Aims Biodiversity is traditionally studied mostly at the species level, but biogeographical and macroecological studies at higher taxonomic levels can provide valuable insights into the evolutionary processes at large spatial scales. Our aim was to assess the representation of vascular plant families within different vegetation formations across Europe. Location Europe. Methods We used a data set of 816,005 vegetation plots from the European Vegetation Archive (EVA). For each plot, we calculated the relative species richness of each plant family as the number of species belonging to that family divided by the total number of species. We mapped the relative species richness, averaged across all plots in 50 km × 50 km grid cells, for each family and broad habitat groups: forests, grasslands, scrub and wetlands. We also calculated the absolute species richness and the Shannon diversity index for each family. Results We produced 522 maps of mean relative species richness for a total of 152 vascular plant families occurring in forests, grasslands, scrub and wetlands. We found distinct spatial patterns for many combinations of families and habitat groups. The resulting series of 522 maps is freely available, both as images and GIS layers. Conclusions The distinct spatial patterns revealed in the maps suggest that the relative species richness of plant families at the community level reflects the evolutionary history of individual families. We believe that the maps and associated data can inspire further biogeographical and macroecological studies and strengthen the ongoing integration of phylogenetic, functional and taxonomic diversity concepts.
Motivation Indicator values are numerical values used to characterize the ecological niches of species and to estimate their occurrence along gradients. Indicator values on climatic and edaphic niches of plant species have received considerable attention in ecological research, whereas data on the optimal positioning of species along disturbance gradients are less developed. Here, we present a new data set of disturbance indicator values identifying optima along gradients of natural and anthropogenic disturbance for 6382 vascular plant species based on the analysis of 736,366 European vegetation plots and using expert‐based characterization of disturbance regimes in 236 habitat types. The indicator values presented here are crucial for integrating disturbance niche optima into large‐scale vegetation analyses and macroecological studies. Main types of variables contained We set up five main continuous indicator values for European vascular plants: disturbance severity, disturbance frequency, mowing frequency, grazing pressure and soil disturbance. The first two indicators are provided separately for the whole community and for the herb layer. We calculated the values as the average of expert‐based estimates of disturbance values in all habitat types where a species occurs, weighted by the number of plots in which the species occurs within a given habitat type. Spatial location and grain Europe. Vegetation plots ranging in size from 1 to 1000 m2. Time period and grain Vegetation plots mostly sampled between 1956 and 2013 (= 5th and 95th quantiles of the sampling year, respectively). Major taxa and level of measurement Species‐level indicator values for vascular plants. Software format csv file.
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
Annual shoots of 46 terrestrial orchid species commonly found in wide ranges of temperate climates in Russia and Japan change their patterns of growth recurrence from the dormancy state, through formation and growth, to the next dormancy state during the course of yearly response to seasonal cycles of environmental conditions. Each of the species has its own strategy in seasonal development of aerial shoots, rhizomes, tubers and roots, and shows seasonal differentiation of shoot morphogenesis at the early stage of new shoot apex formation in accordance with its growth habit, habitat and range size of geographical distribution. Perennial orchids with sympodial growth patterns and primitive life forms are characterized by long duration of shoot and inflorescence development inside the bud. Among the species studied, the orchids that have annually regenerating root‐stem tubers have the shortest duration of root and shoot morphogenesis. The species that have predominant patterns of monopodial growth show variability in duration of lateral shoot growth due to the energy budget of the mother plant. The species which have latitudinally long ranges of distribution from northern colder regions to southern warmer regions tend to take longer for shoot development inside the bud, and aerial shoots have a shorter life‐span in the northern regions than those in the south.
Lesser Twayblade. Orchidaceae, subfamily Epidendroideae, tribe
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.
1. This account presents information on all aspects of the biology of Neottia ovata (L.) Bluff & Fin-gerh. (Common Twayblade; Listera ovata (L.) R. Br.) that are relevant to an understanding of its ecological characteristics and behaviour. The main topics are presented within the standard framework of the Biological Flora of the British Isles: distribution, habitat, communities, responses to bio-tic factors, responses to environment, structure and physiology, phenology, reproductive characteristics, herbivores, history and conservation. 2. Neottia ovata is one of the commonest orchids in the British Isles. It occupies a wide range of habitats from lowlands to mountains and from wet to dry sites: deciduous broadleaved and mixed woodland, forest edges, calcareous grassland and scrub, hedgerows, dry meadows, pastures, sand dunes, fens, floodplains and some anthropogenic sites. 3. Neottia ovata is a perennial herb whose populations are maintained predominantly by sexual reproduction, as vegetative spread is limited. The main perennating organ is a horizontal rhizome that produces a new internode every year. The numerous adventitious roots are mainly colonized by Basidiomycota from Sebacinales (Clade B) but also by several other fungal groups. Dormancy, that is the failure of above-ground parts to appear in a growing season, followed by reappearance of full-sized photosynthetic plants in subsequent seasons, has been occasionally observed and typically lasts for one, or sometimes 2 years. 4. The species flowers from early May to the beginning of July, or August at higher altitudes. The flowers of the genus Neottia possess a sensitive rostellum that releases a viscid fluid when it is touched, gluing the pollinia to the pollinator. N. ovata is pollinated mainly by three insect groups: ichneumonids, sawflies and beetles. The mean fraction of flowers setting fruit is c. 40%, but it depends on weather conditions: in rainy weather, it decreases to 10%, and in warm, dry weather, it can increase to 100%. Spontaneous autogamy is rare (1% of flowers). 5. Neottia ovata is classified as a species of Least Concern in Great Britain. Although it appears well adapted to countryside changes, thanks to its wide habitat range, the species has vanished from almost 30% of its historical sites in Britain and Ireland. Agricultural activities are mainly responsible for losses of N. ovata sites in the lowlands.
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