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Peatlands are strategic areas for climate change mitigation because of their matchless carbon stocks. Drained peatlands release this carbon to the atmosphere as carbon dioxide (CO 2 ). Peatland rewetting effectively stops these CO 2 emissions, but also re-establishes the emission of methane (CH 4 ). Essentially, management must choose between CO 2 emissions from drained, or CH 4 emissions from rewetted, peatland. This choice must consider radiative effects and atmospheric lifetimes of both gases, with CO 2 being a weak but persistent, and CH 4 a strong but short-lived, greenhouse gas. The resulting climatic effects are, thus, strongly time-dependent. We used a radiative forcing model to compare forcing dynamics of global scenarios for future peatland management using areal data from the Global Peatland Database. Our results show that CH 4 radiative forcing does not undermine the climate change mitigation potential of peatland rewetting. Instead, postponing rewetting increases the long-term warming effect through continued CO 2 emissions. Drained peatlands are sources of CO 2 , and though rewetting could curb emissions, this strategy results in elevated methane release. Here, the authors model peatland emissions scenarios and show that rewetting is a critical way to mitigate climate change despite potential methane increases.

Wetlands have long been drained for human use, thereby strongly affecting greenhouse gas fluxes, flood control, nutrient cycling and biodiversity. Nevertheless, the global extent of natural wetland loss remains remarkably uncertain. Here, we reconstruct the spatial distribution and timing of wetland loss through conversion to seven human land uses between 1700 and 2020, by combining national and subnational records of drainage and conversion with land-use maps and simulated wetland extents. We estimate that 3.4 million km2 (confidence interval 2.9–3.8) of inland wetlands have been lost since 1700, primarily for conversion to croplands. This net loss of 21% (confidence interval 16–23%) of global wetland area is lower than that suggested previously by extrapolations of data disproportionately from high-loss regions. Wetland loss has been concentrated in Europe, the United States and China, and rapidly expanded during the mid-twentieth century. Our reconstruction elucidates the timing and land-use drivers of global wetland losses, providing an improved historical baseline to guide assessment of wetland loss impact on Earth system processes, conservation planning to protect remaining wetlands and prioritization of sites for wetland restoration.

In spite of the worldwide largest proportional loss of mires, Europe is a continent with important mire diversity. This article analyses the condition and protection status of European mire ecosystems. The overview is based on the system of European mire regions, representing regional variety and ecosystem biodiversity. We combined peatland distribution data with land cover maps of the Copernicus Land Monitoring Service as well as with the World Database on Protected Areas to assess the extent of degraded peatlands and the proportion of peatlands located in protected areas in each European mire region. The total proportion of degraded peatlands in Europe is 25%; within the EU it is 50% (120,000 km2). The proportion of degradation clearly increases from north to south, as does the proportion of peatlands located within protected areas. In more than half of Europe’s mire regions, the target of at least 17% of the area located in protected areas is not met with respect to peatlands. Data quality is discussed and the lessons learned from Europe for peatland conservation are presented.

We studied a pristine, prominently patterned raised bog in Tierra del Fuego, Argentina, to disentangle the complex interactions among plants and water and peat. The studied bog lacks complicating features often posed by other bogs. It is completely dominated by Sphagnum magellanicum, which covers all niches and growth forms, and is joined by only a dozen higher plant species; it is entirely ombrotrophic with very sharp borders to the surrounding fen; it has only one type of peat that shows an only limited range in degree of decomposition; and it is situated in a very even climate with minimal differences in rainfall and temperature over the year. We present detailed measurements along a 498‐m‐long transect crossing the bog, including water table measurements (n = 498), contiguous vegetation relevés (n = 248), hydraulic conductivity just below the water table (n = 246), and hydraulic conductivity in 11 depth profiles (n = 291); degree of humification of the corresponding peat was assessed in conjunction with the hydraulic conductivity measurements (n = 537). Sphagnum magellanicum moss samples were collected every 2 m along this transect as well and genotyped (n = 242). In addition, along short, 26‐m‐long transects crossing strings and flarks water table and hydraulic conductivity just below the water table were measured every meter. Sphagnum growth forms were assessed, and the vegetation of the entire bog was mapped in 10 × 10‐m relevés (n = 3322). A simulation model was applied to a generalized shape of the bog and produced surface patterns that well matched those seen in the field. The results were integrated with information from the literature and discussed in the framework of a self‐regulating and self‐organizing raised bog. We identified 19 hydrological feedback mechanisms. We found that the various mechanisms overlap in both space and time, which means there is redundancy in the self‐regulation of the system. Raised bogs, when in a natural state, are among the most resilient ecosystems known; resilience that is provided by feedbacks and backup systems to these feedbacks.

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.

Rewetting is the most effective way to reduce greenhouse gas (GHG) emissions from drained peatlands and must significantly contribute to the implementation of the Paris Agreement on Climate within the land sector. In 2010–2013, more than 73 thousand hectares of fire-prone peatlands were rewetted in the Moscow Region (the hitherto largest rewetting program in the Northern Hemisphere). As the Russian Federation has no national accounting of rewetted areas yet, this paper presents an approach to detect them based on multispectral satellite data verified by ground truthing. We propose that effectively rewetted areas should minimally include areas with wet grasslands and those covered with water (cf. the IPCC categories “rewetted organic soils” and “flooded lands”). In 2020, these lands amounted in Moscow Region to more than 5.3 and 3.6 thousand hectares, respectively. Assuming that most rewetted areas were former peat extraction sites and using IPCC default GHG emission factors, an overall GHG emission reduction of over 36,000 tCO2-eq year−1 was calculated. We furthermore considered the uncertainty of calculations. With the example of a 1535 ha large rewetted peatland, we illustrate the estimation of GHG emission reductions for the period up to 2050. The approach presented can be used to estimate GHG emission reductions by peatland rewetting on the national, regional, and object level.

Of all terrestrial ecosystems, peatlands store carbon most effectively in long-term scales of millennia. However, many peatlands have been drained for peat extraction or agricultural use. This converts peatlands from sinks to sources of carbon, causing approx. 5% of the anthropogenic greenhouse effect and additional negative effects on other ecosystem services. Rewetting peatlands can mitigate climate change and may be combined with management in the form of paludiculture. Rewetted peatlands, however, do not equal their pristine ancestors and their ecological functioning is not understood. This holds true especially for groundwater-fed fens. Their functioning results from manifold interactions and can only be understood following an integrative approach of many relevant fields of science, which we merge in the interdisciplinary project WETSCAPES. Here, we address interactions among water transport and chemistry, primary production, peat formation, matter transformation and transport, microbial community, and greenhouse gas exchange using state of the art methods. We record data on six study sites spread across three common fen types (Alder forest, percolation fen, and coastal fen), each in drained and rewetted states. First results revealed that indicators reflecting more long-term effects like vegetation and soil chemistry showed a stronger differentiation between drained and rewetted states than variables with a more immediate reaction to environmental change, like greenhouse gas (GHG) emissions. Variations in microbial community composition explained differences in soil chemical data as well as vegetation composition and GHG exchange. We show the importance of developing an integrative understanding of managed fen peatlands and their ecosystem functioning.

Sacred forests are of immense value for their ecosystem functions. Traditional indigenous conservation practices have helped to maintain biological diversity over centuries and have resulted in the preservation of some of the best patches of natural vegetation. Species that are endemic and restricted only to certain ecosystems find refuge in the micro-climatic conditions of sacred groves and many rare species are found here. Here, we compared species composition, floristic structure, diversity, and occurrence of amphibians, insects (odonatan) and birds in ten sacred swamps and ten non-sacred swamps in the central Western Ghats region, India. The sites were chosen based on similarities in distance from roads, village settlements, or commercial orchards and size. In the sacred swamps, 122 plant species from 99 genera and 58 families occur compared to 83 species from 72 genera and 47 families in the non-sacred swamps. Tree stem density was 277 individuals/ha in sacred swamps against 158.4 in nonsacred swamps. Average basal area was 47.57 m2/ha in sacred swamps and only 14.60 m2/ha in non-sacred swamps. Regeneration of swampy species is much better in sacred swamps showing a positively skewed distribution of individuals over all classes. Sacred swamps have a higher number of endemic species (28%) when compared to non-sacred swamps. There exist significant differences in the Shannon index of species diversity of amphibians and birds between sacred and to non-sacred swamps. We conclude that the traditional belief system of treating the swamps as sacred has helped to protect these ecologically important forests. Sacred forests are of immense value for their ecosystem functions. Traditional indigenous conservation practices have helped to maintain biological diversity over centuries and have resulted in the preservation of some of the best patches of natural vegetation.

The increasing global demand for vegetable oils has resulted in a significant increase in the area under oil palm in the tropics during the last couple of decades, and this is projected to increase further. The Roundtable on Sustainable Palm Oil discourages the conversion of peatlands to oil palm and rubber plantations. However, our understanding of the effects on soil organic carbon (SOC) stocks and associated greenhouse gas (GHG) emissions of land use conversion is incomplete, especially for mineral soils under primary forests, secondary forests, rubber and other perennial plantations in the tropics. In this review we synthesised information on SOC stocks and GHG emissions from tropical mineral soils under forest, oil palm and rubber plantations and other agroecosystems across the tropical regions. We found that the largest SOC losses occurred after land use conversion from primary forest to oil palm and rubber plantations. Secondary forest and pasture lands showed lower SOC losses as well as total GHG (CO2, N2O and CH4) emissions when converted to oil palm and rubber plantations. However, due to the limited data available on all three GHG emissions, there remains high uncertainty in GHG emissions estimates, and regional GHG accounting is more reliable. We recommend long-term monitoring of oil palm and other perennial plantations established on tropical mineral soils on different soil types and regions on SOC stock changes and total GHG emissions and evaluate appropriate management practices to optimise production and sustainable economic returns, and minimise environmental impact.