Editorial: Ecological Development and Functioning of Biological Soil Crusts After Natural and Human Disturbances

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Does pollen-assemblage richness reflect floristic richness? A review of recent developments and future challenges

Current interest and debate on pollen-assemblage richness as a proxy for past plant richness have prompted us to review recent developments in assessing whether modern pollen-assemblage richness reflects contemporary floristic richness. We present basic definitions and outline key terminology. We summarise four basic needs in assessing pollen–plant richness relationships — modern pollen data, modern vegetation data, pollen–plant translation tables, and quantification of the co-variation between modern pollen and vegetation compositional data. We discuss three key estimates and one numerical tool — richness estimation, evenness estimation, diversity estimation, and statistical modelling. We consider the inherent problems and biases in assessing pollen–plant richness relationships — taxonomic precision, pollen-sample:pollen-population ratios, pollen-representation bias, and underlying concepts of evenness and diversity. We summarise alternative approaches to studying pollen–plant richness relationships. We show that almost all studies which have compared modern pollen richness with contemporary site-specific plant richness reveal good relationships between palynological richness and plant richness. We outline future challenges and research opportunities — interpreting past pollen-richness patterns, estimating richness from macrofossils, studying pollen richness at different scales, partitioning diversity and estimating beta diversity, estimating false, hidden, and dark richness, and considering past functional and phylogenetic diversity from pollen data. We conclude with an assessment of the current state-of-knowledge about whether pollen richness reflects floristic richness and explore what is known and unknown in our understanding of pollen–plant richness relationships.acceptedVersio

The potential to use documentation in national Red Lists to characterize red-listed forest species in Fennoscandia and to guide conservation

Loss of biodiversity is a pressing global issue, hence it is vital to facilitate informed and effective conservation. As conservation mainly operates at the level of habitats, aiming for species of conservation interest, conservation and management require adequate ecological knowledge of prioritized species for the geographic and environmental setting considered. Our aim was to investigate if ecological documentation in national Red Lists could be combined and used to identify important forest habitats and ecological variables for red-listed forest species in Fennoscandia, and whether this knowledge could be arranged at different geographical scales and for various selections of species of conservation interest. We compiled the national Red Lists of Finland, Norway and Sweden and extracted ecological information for all red-listed forest species (n = 4830). We used a principal component analysis to investigate variation in distribution of species and their habitat associations and taxonomical groups, and to group species of similar associations. We further used the listed species in Sweden as an example, and compared the proportions of species associated to the ecological variables dead wood, living trees or merely the "forest floor and understory" a) at larger and smaller scale (Fennoscandia - county in Sweden), b) in regions with contrasting biomes (nemoral and boreal), and c) in two more limited selections of species of conservation interest; Fennoscandian and globally red-listed species also red-listed in Sweden. Ecological information could be extracted for 96% of the species, albeit with a low resolution; i.e. overall forest habitats, associated tree species, lifeforms and six other ecological variables selected based on their frequent appearance in the Red List documentation. Using this information, we identified five large-scale patterns for Fennoscandian red-listed species; the majority of red-listed species is associated with coniferous forest. The number of red-listed species associated with specific tree species was poorly correlated with the amount of each tree species in Fennoscandia. Dead wood was one of the most important habitat features in terms of number of associated red-listed species, and the proportion of species associated to dead wood was similar in coniferous, boreal and nemoral broad-leaved forests types. We demonstrate that ecological documentation in national Red Lists can be used to identify general ecological variables at varying geographical scales and for different selections of species, albeit not with sufficient resolution to provide detailed local conservation guidelines. (C) 2018 The Authors. Published by Elsevier B.V.Peer reviewe

Rate-of-change analysis in palaeoecology revisited: a new approach

Dynamics in the rate of compositional change (rate-of-change; RoC), preserved in paleoecological sequences, are thought to reflect changes due to exogenous (climate and human forcing) or endogenous (local dynamics and biotic interactions) drivers. However, changes in sedimentation rates and sampling strategies can result in an uneven distribution of time intervals and are known to affect RoC estimates. Furthermore, there has been relatively little exploration of the implications of these challenges in quantifying RoC in paleoecology. Here, we introduce R-Ratepol – an easy-to-use R package – that provides a robust numerical technique for detecting and summarizing RoC patterns in complex multivariate time-ordered stratigraphical sequences. First, we compare the performance of common methods of estimating RoC and detecting periods of high RoC (peak-point) using simulated pollen-stratigraphical data with known patterns of compositional change and temporal resolution. In addition, we propose a new method of binning with a moving window, which shows a more than 5-fold increase in the correct detection of peak-points compared to the more traditional way of using individual levels. Next, we apply our new methodology to four representative European pollen sequences and show that our approach also performs well in detecting periods of significant compositional change during known onsets of human activity, early land-use transformation, and changes in fire frequency. Expanding the approach using R-Ratepol to open-access paleoecological datasets in global databases, such as Neotoma, will allow future paleoecological and macroecological studies to quantify major changes in biotic composition or in sets of abiotic variables across broad spatiotemporal scales.publishedVersio

A guide to the processing and standardization of global palaeoecological data for large-scale syntheses using fossil pollen

Aim: Palaeoecological data are crucial for comprehending large-scale biodiversity patterns and the natural and anthropogenic drivers that influence them over time. Over the last decade, the availability of open-access research databases of palaeoecological proxies has substantially increased. These databases open the door to research questions needing advanced numerical analyses and modelling based on big-data compilations. However, compiling and analysing palaeoecological data pose unique challenges that require a guide for producing standardized and reproducible compilations. Innovation: We present a step-by-step guide of how to process fossil pollen data into a standardized dataset compilation ready for macroecological and palaeoecological analyses. We describe successive criteria that will enhance the quality of the compilations. Though these criteria are project and research question-dependent, we discuss the most important assumptions that should be considered and adjusted accordingly. Our guide is accompanied by an R-workflow—called FOSSILPOL—and corresponding R-package—called R-Fossilpol—that provide a detailed protocol ready for interdisciplinary users. We illustrate the workflow by sourcing and processing Scandinavian fossil pollen datasets and show the reproducibility of continental-scale data processing. Main Conclusions: The study of biodiversity and macroecological patterns through time and space requires large-scale syntheses of palaeoecological datasets. The data preparation for such syntheses must be transparent and reproducible. With our FOSSILPOL workflow and R-package, we provide a protocol for optimal handling of large compilations of fossil pollen datasets and workflow reproducibility. Our workflow is also relevant for the compilation and synthesis of other palaeoecological proxies and as such offers a guide for synthetic and cross-disciplinary analyses with macroecological, biogeographical and palaeoecological perspectives. However, we emphasize that expertise and informed decisions based on palaeoecological knowledge remain crucial for high-quality data syntheses and should be strongly embedded in studies that rely on the increasing amount of open-access palaeoecological data.publishedVersio

Exploring spatio-temporal patterns of palynological changes in Asia during the Holocene

Historical legacies influence present-day ecosystem composition and dynamics. It is therefore important to understand the long-term dynamics of ecosystems and their properties. Analysis of ecosystem properties during the Holocene using fossil pollen assemblages provides valuable insights into past ecosystem dynamics by summarising so-called pollen-assemblage properties (PAPs). Using 205 fossil pollen data-sets (records), we quantify eight PAPs [pollen-taxonomic richness, diversity, evenness, pollen-compositional turnover, pollen-compositional change, and rate of pollen-compositional change (RoC)] for the Asian continent at different spatial scales (in individual records, within and across climate-zones, and within the continent) and time (temporal patterns over the past 12,000 years). Regression tree (RT) partitioning of the PAP-estimates using sample-age as a sole predictor revealed the “change-point(s)” (time or sample-age of major change in a PAP). We estimated the density of RT and multivariate regression tree (MRT) change-points in 1,000-year time bins during the Holocene. Pollen-compositional turnover (range of sample scores along the first DCCA axis) and change (number of MRT partitions) in each record reveal gradual spatial variation across latitude and a decline with longitude eastward. Temporally, compositional turnover declines linearly throughout the Holocene at all spatial scales. Other PAPs are heterogeneous across and within spatial scales, being more detectable at coarser scales. RT and MRT change-point density is broadly consistent in climate-zones and the continent, increasing from the early- to mid-Holocene, and mostly decrease from the mid-Holocene to the present for all PAPs. The heterogenous patterns in PAPs across the scales of study most likely reflect responses to variations in regional environmental conditions, anthropogenic land-use, and their interactions over space and time. Patterns at the climate-zone and continental scales indicate a gradual but congruent decline in major PAPs such as compositional turnover, rate of compositional change, and major temporal compositional changes (MRT) during the Holocene, especially during recent millennia, suggesting that vegetation in Asia has become progressively more homogenous. Data properties (e.g., spatial distribution of the records, distribution of samples within the records, and data-standardisation and analytical approaches) may also have partly influenced the results. It is critically important to evaluate the data properties and the approaches to data standardisation and summarisation.publishedVersio

Approaches to pollen taxonomic harmonisation in Quaternary palynology

Pollen taxonomic harmonisation involves the standardisation of the nomenclature of pollen and fern spores with similar morphotypes at the determination level that is common to all grains or spores with that morphotype within the pollen sequence(s) of interest. Such harmonisation is required prior to subsequent investigations such as numerical analysis, comparing, mapping, synthesis, and environmental reconstruction involving several pollen sequences. Here we present two approaches to harmonisation. These are a ‘top-down’ and a ‘bottom-up’ approach. The bottom-up approach is preferred. It is based on the concept of the regional pollen flora for the sequence(s) in the spatial area(s) of study. We present bottom-up harmonisation tables for the continental or sub-continental scales developed for the Humans on Planet Earth (HOPE) project. The tables are for North America, Latin America, Europe, Asia (three parts), and Indo-Pacific. These harmonisations are project-specific and sequence-specific, relating to the geographical area and to the sequences in the area under consideration, both of which are linked to the research questions being addressed. A new bottom-up harmonisation with a consistent taxonomic level and nomenclature is needed when additional sequences or areas are added. However, the HOPE tables can serve as a starting point for further research involving multi-sequence analyses or syntheses.publishedVersio

Evolution of vegetation and climate variability on the Tibetan Plateau over the past 1.74 million years

The Tibetan Plateau exerts a major influence on Asian climate, but its long-term environmental history remains largely unknown. We present a detailed record of vegetation and climate changes over the past 1.74 million years in a lake sediment core from the Zoige Basin, eastern Tibetan Plateau. Results show three intervals with different orbital- and millennial-scale features superimposed on a stepwise long-term cooling trend. The interval of 1.74–1.54 million years ago is characterized by an insolation-dominated mode with strong ~20,000-year cyclicity and quasi-absent millennial-scale signal. The interval of 1.54–0.62 million years ago represents a transitional insolation-ice mode marked by ~20,000- and ~40,000-year cycles, with superimposed millennial-scale oscillations. The past 620,000 years are characterized by an ice-driven mode with 100,000-year cyclicity and less frequent millennial-scale variability. A pronounced transition occurred 620,000 years ago, as glacial cycles intensified. These new findings reveal how the interaction of low-latitude insolation and high-latitude ice-volume forcing shaped the evolution of the Tibetan Plateau climate.publishedVersio

The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe

The preponderance of matter over antimatter in the early Universe, the dynamics of the supernova bursts that produced the heavy elements necessary for life and whether protons eventually decay --- these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our Universe, its current state and its eventual fate. The Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed plan for a world-class experiment dedicated to addressing these questions. LBNE is conceived around three central components: (1) a new, high-intensity neutrino source generated from a megawatt-class proton accelerator at Fermi National Accelerator Laboratory, (2) a near neutrino detector just downstream of the source, and (3) a massive liquid argon time-projection chamber deployed as a far detector deep underground at the Sanford Underground Research Facility. This facility, located at the site of the former Homestake Mine in Lead, South Dakota, is approximately 1,300 km from the neutrino source at Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino charge-parity symmetry violation and mass ordering effects. This ambitious yet cost-effective design incorporates scalability and flexibility and can accommodate a variety of upgrades and contributions. With its exceptional combination of experimental configuration, technical capabilities, and potential for transformative discoveries, LBNE promises to be a vital facility for the field of particle physics worldwide, providing physicists from around the globe with opportunities to collaborate in a twenty to thirty year program of exciting science. In this document we provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess.Comment: Major update of previous version. This is the reference document for LBNE science program and current status. Chapters 1, 3, and 9 provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess. 288 pages, 116 figure

GrassPlot - a database of multi-scale plant diversity in Palaearctic grasslands

GrassPlot is a collaborative vegetation-plot database organised by the Eurasian Dry Grassland Group (EDGG) and listed in the Global Index of Vegetation-Plot Databases (GIVD ID EU-00-003). GrassPlot collects plot records (releves) from grasslands and other open habitats of the Palaearctic biogeographic realm. It focuses on precisely delimited plots of eight standard grain sizes (0.0001; 0.001;... 1,000 m(2)) and on nested-plot series with at least four different grain sizes. The usage of GrassPlot is regulated through Bylaws that intend to balance the interests of data contributors and data users. The current version (v. 1.00) contains data for approximately 170,000 plots of different sizes and 2,800 nested-plot series. The key components are richness data and metadata. However, most included datasets also encompass compositional data. About 14,000 plots have near-complete records of terricolous bryophytes and lichens in addition to vascular plants. At present, GrassPlot contains data from 36 countries throughout the Palaearctic, spread across elevational gradients and major grassland types. GrassPlot with its multi-scale and multi-taxon focus complements the larger international vegetationplot databases, such as the European Vegetation Archive (EVA) and the global database " sPlot". Its main aim is to facilitate studies on the scale-and taxon-dependency of biodiversity patterns and drivers along macroecological gradients. GrassPlot is a dynamic database and will expand through new data collection coordinated by the elected Governing Board. We invite researchers with suitable data to join GrassPlot. Researchers with project ideas addressable with GrassPlot data are welcome to submit proposals to the Governing Board