Distribution and habitat ecology of the threatened forest lichen Lobaria pulmonaria in Estonia

Lobaria pulmonaria is a widely used as an indicator species of undisturbed old-growth forests ecosystems, but the knowledge about its habitat ecology is still highly fragmented. To quantify the distribution, habitat preference and host tree specificity of Lobaria pulmonaria we utilised data from databases and field surveys in Estonia. The number of L. pulmonaria localities is the highest in the densely forested regions, concentrated mainly in small forest patches defined as ‘ecologically highly valuable’. The species grows mostly on deciduous trees, particularly on aspen (Populus tremula). L. pulmonaria is most common in oligo-mesotrophic boreal, eutrophic boreo-nemoral and in eutrophic paludifying forests, and prefers forests with an average age of trees more than 100 years. In addition, we found that younger stands could be suitable habitats for L. pulmonaria if the structure of the stand is comparable to mature stands. In spite of the many localities of L. pulmonaria in Estonia, the species is still threatened because (1) the rotation period of tree stands is short, (2) it is abundant in forest types which are rare or under strong economic pressure, (3) and it prefers host trees which have a restricted distribution in Estonia or are not favoured in forest management practice.

Peltigera (Ascomycota) living in open and shady environments depend on different Nostoc photobionts

Species of Peltigera (lichen-forming Ascomycota) establish obligate symbioses with several monophyletic groups (phylogroups) of Nostoc cyanobacteria. Some of these fungi are strict specialists and only associate with one Nostoc phylogroup throughout their range, while others are generalists and associate with many different Nostoc phylogroups. We sampled 20 Peltigera taxa, mostly representing the Peltigera section Peltigera, from grassland and forest habitats across Europe. Mycobionts’ identities were confirmed using fungal ITS sequences. The Nostoc cyanobionts were identified and grouped based on single nucleotide differences in the trnL region and on the phylogenetic analysis of the rbcLX region. Our data confirmed that some Peltigera species clearly prefer open habitats, while others are largely confined to shady forest habitats. The two habitat preferences are consistently paired with association with different Nostoc groups. As a specific example, two ecologically versatile species, Peltigera canina and P. didactyla, both growing in open and shady habitats, consistently associated with different groups of Nostoc when growing in different habitats. As associations between specific mycobionts and cyanobionts are influenced by habitat conditions, the diversity of both taxon groups should be considered in the context of habitat management and conservation planning

Agricultural sector, rural environment and biodiversity in the Central and Eastern European EU member states

During the second half of the 20th century, agriculture and the rural environment diverged in Westernand Central and Eastern European countries (CEEC). CEE countries itself are heterogeneous in therespect of land use intensity and history. In the current review we focus on the comparison of theagricultural sector and threats on biodiversities of EU new-member countries from Central andEastern Europe and the old EU(15) member states. The clustering of countries revealed groupsdistinguished according to the level of their economic productivity, discriminating mostly amongeastern and western European countries. CEE countries sub-divided according to geographic region,including also some old members of the EU. Within the western cluster, two large sub-clustersbecame evident according to economy affected by altitudinal and climatic differences. Partly becausethere are still areas where the intensity of land use remained low, the biological diversity in manyregions of Central and Eastern Europe has remained high. However, loss of extensively used habitats,the restoration on intensive agriculture, reforestation with exotic species and urbanization are majorthreats to nature in CEE countries. The estimated variability among CEE countries is caused bydifferent historical and cultural backgrounds of those countries. Due to the complexity andgeographical diversity of driving forces, there remains much uncertainty in the possible impacts ofparticular factors on land use. This complexity and diversity have to be considered when planningeconomic as well as ecological means for developing the agricultural sector and conservingbiodiversity in the future of CEE countries

Dispersal ecology of the endangered woodland lichen Lobaria pulmonaria in managed hemiboreal forest landscape

Changes in the forest management practices have strongly influenced the distribution of species inhabiting old-growth forests. The epiphytic woodland lichen Lobaria pulmonaria is frequently used as a model species to study the factors affecting the population biology of lichens. We sampled 252 L. pulmonaria individuals from 12 populations representing three woodland types differing in their ecological continuity and management intensity in Estonia. We used eight mycobiont-specific microsatellite loci to quantify genetic diversity among the populations. We calculated the Sørensen distance to estimate genetic dissimilarity among individuals within populations. We revealed that L. pulmonaria populations have significantly higher genetic diversity in old-growth forests than in managed forests and wooded meadows. We detected a significant woodland-type-specific pattern of genetic dissimilarity among neighbouring L. pulmonaria individuals, which suggests that in wooded meadows and managed forests dominating is vegetative reproduction. The vegetative dispersal distance between the host trees of L. pulmonaria was found to be only 15-30m. Genetic dissimilarity among individuals was also dependent on tree species and trunk diameter. Lobaria pulmonaria populations in managed forests included less juveniles compared to old-growth forests and wooded meadows, indicating that forest management influences life stage structure within populations. We conclude that as intensive stand management reduces the genetic diversity of threatened species in woodland habitats, particular attention should be paid to the preservation of remnant populations in old-growth habitats. Within managed habitats, conservation management should target on maintenance of the stand's structural diversity and availability of potential host tree

Structure and function of the soil microbiome underlying N2O emissions from global wetlands

Wetland soils are the greatest source of nitrous oxide (N2O), a critical greenhouse gas and ozone depleter released by microbes. Yet, microbial players and processes underlying the N2O emissions from wetland soils are poorly understood. Using in situ N2O measurements and by determining the structure and potential functional of microbial communities in 645 wetland soil samples globally, we examined the potential role of archaea, bacteria, and fungi in nitrogen (N) cycling and N2O emissions. We show that N2O emissions are higher in drained and warm wetland soils, and are correlated with functional diversity of microbes. We further provide evidence that despite their much lower abundance compared to bacteria, nitrifying archaeal abundance is a key factor explaining N2O emissions from wetland soils globally. Our data suggest that ongoing global warming and intensifying environmental change may boost archaeal nitrifiers, collectively transforming wetland soils to a greater source of N2O.The wetland soil microbiome has a major impact on greenhouse gas emissions. Here the authors characterize how a group of archaea contribute to N2O emissions and find that climate and land use changes could promote these organisms

Agriculture intensification reduces plant taxonomic and functional diversity across European arable systems

Los autores de la UAM pertenecen al Terrestrial Ecology Group (TEG)Agricultural intensification is one of the main drivers of species loss worldwide, but there is still a lack of information about its effect on functional diversity of arable weed communities. Using a large-scale pan European study including 786 fields within 261 farms from eight countries, we analysed differences in the taxonomic and functional diversity of arable weeds assemblages across different levels of agricultural intensification. We estimated weed species frequency in each field, and collected species' traits (vegetative height, SLA and seed mass) from the TRY plant trait database. With this information, we estimated taxonomic (species richness), functional composition (community weighted means) and functional diversity (functional richness, evenness, divergence and redundancy). We used indicators of agricultural management intensity at the individual field scale (e.g. yield, inputs of nitrogen fertilizer and herbicides, frequency of mechanical weed control practices) and at the landscape scale surrounding the field (i.e. number of crop types, mean field size and proportion of arable land cover within a radius of 500 m from the sampling points). The effects of agricultural intensification on species and functional richness at the field scale were stronger than those of intensification at the landscape scale, and we did not observe evidence of interacting effects between the two scales. Overall, assemblages in more intensified areas had fewer species, a higher prevalence of species with ruderal strategies (low stature, high leaf area, light seeds), and lower functional redundancy. Maintaining the diversity of Europe's arable weed communities requires some simple management interventions, for example, reducing the high intensity of field-level agricultural management across Europe, which could be complemented by interventions that increase landscape complexity. A free Plain Language Summary can be found within the Supporting Information of this articl

Hedging against biodiversity loss : forest herbs’ performance in hedgerows across temperate Europe

Questions: How do contrasting environmental conditions among forests and hedgerows affect the vegetative and reproductive performance of understorey forest herbs in both habitats? Can hedgerows support reproductive source populations of forest herbs, thus potentially allowing progressive dispersal of successive generations along these linear habitats? Location: Hedgerows and deciduous forest patches in agricultural landscapes across the European temperate biome. Methods: First, we assessed differences in environmental conditions among forests and hedgerows. Next, we quantified plant performance based on a set of functional life‐history traits for four forest herbs (Anemone nemorosa, Ficaria verna, Geum urbanum, Poa nemoralis) with contrasting flowering phenology and colonisation capacity in paired combinations of forests and hedgerows, and compared these traits among both habitats. Finally, we assessed relationships between plant performance and environmental conditions in both habitats. Results: All study species showed a higher above‐ground biomass in hedgerows than in forests. For Poa nemoralis and Geum urbanum, we also found a higher reproductive output in hedgerows, which was mainly correlated to the higher sub‐canopy temperatures therein. The “ancient forest herb” Anemone nemorosa, however, appeared to have a lower reproductive output in hedgerows than in forests, while for Ficaria verna no reproductive differences were found between the two habitats. Conclusions: This is the first study on such a broad geographical scale to provide evidence of reproductive source populations of forest herbs in hedgerows. Our findings provide key information on strategies by which forest plants grow, reproduce and disperse in hedgerow environments, which is imperative to better understand the dispersal corridor function of these wooded linear structures. Finally, we highlight the urgent need to develop guidelines for preserving, managing and establishing hedgerows in intensive agricultural landscapes, given their potential to contribute to the long‐term conservation and migration of forest herbs in the face of global environmental change

Structure and function of the soil microbiome underlying N2O emissions from global wetlands

Wetland soils are the greatest source of nitrous oxide (N2O), a critical greenhouse gas and ozone depleter released by microbes. Yet, microbial players and processes underlying the N2O emissions from wetland soils are poorly understood. Using in situ N2O measurements and by determining the structure and potential functional of microbial communities in 645 wetland soil samples globally, we examined the potential role of archaea, bacteria, and fungi in nitrogen (N) cycling and N2O emissions. We show that N2O emissions are higher in drained and warm wetland soils, and are correlated with functional diversity of microbes. We further provide evidence that despite their much lower abundance compared to bacteria, nitrifying archaeal abundance is a key factor explaining N2O emissions from wetland soils globally. Our data suggest that ongoing global warming and intensifying environmental change may boost archaeal nitrifiers, collectively transforming wetland soils to a greater source of N2O

Sensitivity to habitat fragmentation across European landscapes in three temperate forest herbs

Context Evidence for effects of habitat loss and fragmentation on the viability of temperate forest herb populations in agricultural landscapes is so far based on population genetic studies of single species in single landscapes. However, forest herbs differ in their life histories, and landscapes have different environments, structures and histories, making generalizations difficult. Objectives We compare the response of three slow-colonizing forest herbs to habitat loss and fragmentation and set this in relation to differences in life-history traits, in particular their mating system and associated pollinators. Methods We analysed the herbs' landscape-scale population genetic structure based on microsatellite markers from replicate forest fragments across seven European agricultural landscapes. Results All species responded to reductions in population size with a decrease in allelic richness and an increase in genetic differentiation among populations. Genetic differentiation also increased with enhanced spatial isolation. In addition, each species showed unique responses. Heterozygosity in the self-compatible Oxalis acetosella was reduced in smaller populations. The genetic diversity of Anemone nemorosa, whose main pollinators are less mobile, decreased with increasing spatial isolation, but not that of the bumblebee-pollinated Polygonatum multiflorum. Conclusions Our study indicates that habitat loss and fragmentation compromise the long-term viability of slow-colonizing forest herbs despite their ability to persist for many decades by clonal propagation. The distinct responses of the three species studied within the same landscapes confirm the need of multi-species approaches. The mobility of associated pollinators should be considered an important determinant of forest herbs' sensitivity to habitat loss and fragmentation