Hans Joosten

Assessing greenhouse gas emissions from peatlands using vegetation as a proxy

Drained peatlands in temperate Europe are a globally important source of greenhouse gas (GHG) emissions. This article outlines a methodology to assess emissions and emission reductions from peatland rewetting projects using vegetation as a proxy. Vegetation seems well qualified for indicating GHG fluxes from peat soils as it reflects long-term water level, affects GHG emissions via assimilate supply and aerenchyma and allows fine-scaled mapping. The methodology includes mapping of vegetation types characterised by the presence and absence of species groups indicative for specific water level classes. GHG flux values are assigned to the vegetation types following a standardized protocol and using published emission values from plots with similar vegetation and water level in regions with similar climate and flora. Carbon sequestration in trees is accounted for by estimating the annual sequestration in tree biomass from forest inventory data. The method follows the criteria of the Voluntary Carbon Standard and is illustrated using the example of two Belarusian peatlands.

Hydrological landscape settings of base-rich fen mires and fen meadows: an overview

ABSTRACT Question: Why do similar fen meadow communities occur in different landscapes? How does the hydrological system sustain base-rich fen mires and fen meadows? Location: Interdunal wetlands and heathland pools in The Netherlands, percolation mires in Germany, Poland, and Siberia, and calcareous spring fens in the High Tatra, Slovakia. Methods: This review presents an overview of the hydrological conditions of fen mires and fen meadows that are highly valued in nature conservation due to their high biodiversity and the occurrence of many Red List species. Fen types covered in this review include: (1) small hydrological systems in young calcareous dune areas, and (2) small hydrological systems in decalcified old cover sand areas in The Netherlands; (3) large hydrological systems in river valleys in Central-Europe and western-Siberia, and (4) large hydrological systems of small calcareous spring fens with active precipitation of travertine in mountain areas of Slovakia. Results: Different landscape types can sustain similar nutrient poor and base-rich habitats required by endangered fen meadow species. The hydrological systems of these landscapes are very different in size, but their groundwater flow pattern is remarkably similar. Paleo-ecological research showed that travertine forming fen vegetation types persisted in German lowland percolation mires from 6000 to 3000 BP. Similar vegetation types can still be found in small mountain mires in the Slovak Republic. Small pools in such mires form a cascade of surface water bodies that stimulate travertine formation in various ways. Travertine deposition prevents acidification of the mire and sustains populations of basiphilous species that elsewhere in Europe are highly endangered. Conclusion: Very different hydrological landscape settings can maintain a regular flow of groundwater through the top soil generating similar base-rich site conditions. This is why some fen species occur in very different landscape types, ranging from mineral interdunal wetlands to mountain mires.

What’s in a name?: Some thoughts on pollen classification, identification, and nomenclature in Quaternary palynology

Abstract Recent developments in Quaternary palaeopalynology necessitate an increased attention to the classification and nomenclature of pollen types. This paper discusses the differences between palaeopalynological and actuo pollen morphological pollen classification and their consequences for pollen identification and for the interpretation of pollen data. The obscure character of pollen types, that leads to confusion in pollen typology and nomenclature, is analysed and various nomenclatural approaches are reviewed. It is concluded that fossil pollen can not – beyond reasonable doubt – be ascribed to recent and native taxa that produce the same kind of pollen. A pollen type should therefore be defined as a limitative collection of morphological properties (e.g. by reference to a concrete key), not as pollen of a taxon. All types distinguished have to be defined separately (e.g. by referring to a concrete key in the name of every pollen type), when various keys are used in combination or when types deviate from types in those keys. Observed pollen types and interpreted taxa should be kept clearly separated in the discussion. Finally, some suggestions are offered for putting these conclusions into practice.

Pollen productivity estimates strongly depend on assumed pollen dispersal

Past plant abundance may be reconstructed from pollen data if dispersal distances of pollen and pollen productivities of each taxon are known. Using surface sediment samples from small and medium sized, closed and near circular lakes from lowland Central Europe, we tested the validity of three pollen dispersal models by comparing empirical pollen data from each lake with simulated pollen data derived from applying various pollen dispersal models to vegetation data from rings situated up to 100 km from each site. Pollen assemblages simulated with a Lagrangian stochastic (LS) model best fit real pollen assemblages, simulations with the commonly used Prentice model on pollen dispersal underestimated the amount of pollen arriving from distances larger than 10 km and overestimated the differences in dispersal distances between lighter (Pinus) and heavier (Fagus, Picea) pollen grains. The LS model appeared to provide more appropriate simulations. Pollen productivity estimates (PPEs) calculated for the data set showed that the choice of the dispersal model has great impact on the results. If derived with the Prentice model, PPEs for Fagus and Picea are three times higher than with the LS model. Studies on pollen productivities thus need to consider the apparent limitations of the Prentice model. We suggest an alternative approach, which uses simulations instead of the extended R-value model, to calculate PPEs. The approach is flexible in the use of dispersal functions and produced consistent results for two independent data sets from small and medium sized lakes.

Comparison of methods for measuring and assessing carbon stocks and carbon stock changes in terrestrial carbon pools. How do the accuracy and precision of current methods compare? A systematic review protocol

BackgroundClimate change and high rates of global carbon emissions have focussed attention on the need for high-quality monitoring systems to assess how much carbon is present in terrestrial systems and how these change over time. The choice of system to adopt should be guided by good science. There is a growing body of scientific and technical information on ground-based and remote sensing methods of carbon measurement. The adequacy and comparability of these different systems have not been fully evaluated.MethodsA systematic review will compare methods of assessing carbon stocks and carbon stock changes in key land use categories, including, forest land, cropland, grassland, and wetlands, in terrestrial carbon pools that can be accounted for under the Kyoto protocol (above- ground biomass, below-ground biomass, dead wood, litter and soil carbon). Assessing carbon in harvested wood products will not be considered in this review.DiscussionDeveloping effective mitigation strategies to reduce carbon emissions and equitable adaptation strategies to cope with increasing global temperatures will rely on robust scientific information that is free from biases imposed by national and commercial interests. A systematic review of the methods used for assessing carbon stocks and carbon stock changes will contribute to the transparent analysis of complex and often contradictory science.

Vegetation characteristics and eco-hydrological processes in a pristine mire in the Ob River valley (Western Siberia)

Relations between vegetation characteristics and eco-hydrological processes were assessed in a pristine mire in the valley of the Ob River (Western Siberia). Along a transect from the terrace scarp to the river, field data were collected on vegetation composition, peat stratigraphy, peat chemistry, hydrology and hydrochemistry. Based on floristic composition, eight vegetation communities were distinguished. Hydraulic head measurements were used to obtain an indication of groundwater flow directions. The water balance of the mire was calculated with a two-dimensional steady-state numerical groundwater model. Water types were defined based on cluster analysis of hydrochemical data. The results revealed that the dominant hydrological factor in the Ob mire is the discharge of groundwater, which supplies about threefold more water than net precipitation. Although the discharge flux decreases with increasing distance from the terrace scarp, high water levels and a “groundwater-like” mire water composition were observed in the major part of the study site. Precipitation and river water play only a minor role. Despite dilution of discharging groundwater with rainwater, spatial differences in pH and solute concentrations of the surficial mire water are small and not reflected in the vegetation composition. Although small amounts of silt and clay were found in the peat in the proximity of the river, indicating the occurrence of river floods in former times, no river-flood zone could be recognized based on hydrochemical characteristics or vegetation composition. A comparison of the Ob mire with well-studied and near-natural mires in the Biebrza River valley (Poland) revealed substantial differences in both vegetation characteristics and the intensity and spatial pattern of eco-hydrological processes. Differences in the origin and ratios of water fluxes as well as a dissimilar land use history would seem to be key factors explaining the differences observed.

Benefits of soil carbon: report on the outcomes of an international scientific committee on problems of the environment rapid assessment workshop

A Scientific Committee on Problems of the Environment Rapid Assessment (SCOPE-RAP) workshop was held on 18–22 March 2013. This workshop was hosted by the European Commission, JRC Centre at Ispra, Italy, and brought together 40 leading experts from Africa, Asia, Europe and North and South America to create four synthesis chapters aimed at identifying knowledge gaps, research requirements, and policy innovations. Given the forthcoming publication by CABI of a book volume of the outcomes of the SCOPE-RAP in 2014, this workshop report provides an update on the global societal challenge of soil carbon management and some of the main issues and solutions that were identified in the four working sessions.

In search of finiteness: the limits of fine-resolution palynology of Sphagnum peat:

High-resolution analysis of ombrogenous peats often reveals pollen frequencies that change markedly from one sample to the next, indicating limited postdepositional mixing. This raises the question whether — with sufficiently thin samples — seasonal differences in pollen deposition can be observed. Seasonal resolution in peat would provide a dating technique with an accuracy similar to that of other, annually banded archives. To study the limits of temporal resolution, contiguous 0.5 mm thick slices of slightly humified Sphagnum section Cuspidata peat were palynologically analysed. No seasonal patterns in the pollen stratigraphy could be observed. This is ascribed to the mixing of pollen grains as a result of small-scaled vertical water movements and to the horizontal mode of shoot layering in the Sphagnum species. The latter process may also be the cause of a smoothed annual signal. Because of the absence of seasonal differentiation, the palynological distinction of annual peat layers is not feasible.

Forest dynamics and tip‐up pools drive pulses of high carbon accumulation rates in a tropical peat dome in Borneo (Southeast Asia)

Singapore. National Research Foundation (Singapore-MIT Alliance for Research and Technology)

Peatland Restoration and Ecosystem Services: Science, Policy and Practice

Peatlands provide globally important ecosystem services through climate and water regulation or biodiversity conservation. While covering only 0.4 per cent of the Earth’s surface, degrading peatlands are responsible for nearly a quarter of carbon emissions from the land-use sector. Bringing together world-class experts from science, policy and practice to highlight and debate the importance of peatlands from an ecological, social and economic perspective, this book focuses on how peatland restoration can foster climate change mitigation. Featuring a range of global case studies, opportunities for reclamation and sustainable management are illustrated throughout against the challenges faced by conservation biologists. Written for a global audience of environmental scientists, practitioners and policy makers, as well as graduate students from natural and social sciences, this interdisciplinary book provides vital pointers towards managing peatland conservation in a changing environment.