Anthropogenic drainage and cutting over of peatlands have historically occurred worldwide leading to erosion, issues with water quality, loss of biodiversity, and reduced rates of carbon accumulation. In recent years, rewetting measures have attempted to address these issues. Creating dams to block drainage ditches on peatlands is a common restoration tool, yet the ecological consequences of such management interventions are poorly understood. In particular, knowledge about the ecology of the thousands of pools created by drain blocking is limited even though they potentially provide valuable new habitat for aquatic species and food and water sources for terrestrial organisms. More research is needed to assess the suitability of these artificial pools as surrogates for naturally occurring peat pools with regard to the flora (e.g., bryophytes, algae, and macrophytes) and fauna (e.g., invertebrates and amphibians), which utilize them. Evidence suggests that (1) to maximize benefits to aquatic biota, land managers should consider creating an array of differently sized pools behind the dams as a broader size range would facilitate colonization by a wider range of taxa, (2) prioritizing landscapes close to existing water bodies would encourage faster colonization, and (3) even newly created pools with low macrophyte cover may be able to sustain substantial populations of larger fauna via algal primary production, consumption of detritus, and microbial processing of humic substances and methane. Ongoing programs of peatland restoration worldwide also afford unique opportunities to study how pool communities assemble and change over time. © potential to rapidly release it when they become degraded. 4,5 Peatlands are subdivided into bogs, which are ombrotrophic (exclusively rain-fed), and fens, which are minerotrophic (influenced by groundwater). However, a peatland landscape may contain areas of both fen and bog. For example, while raised bog massifs (dome-like structures of peat) are indeed exclusively ombrotrophic, 2 they can be found within a wider landscape which reflects a trophic gradient, including minerotrophic sources and transitional (lagg) zones. 6 Likewise, blanket mires (in which peat cloaks the landscape in a layer that reflects the underlying topography) are mainly ombrotrophic (blanket bog) but may also contain areas of minerotrophic fen.2 Blanket mire is a globally scarce habitat, which This review concentrates mainly on pools that form on areas of ombrotrophic bog, but takes into account trophic gradients when studies have looked at the wider peatland landscape, see Refs 6, 7. Permanent pools are common features on many northern bogs (Figure 1). They constitute one of a series of nanotopes (small-scale structural elements also known as microforms) 2 (Table 1) and there are many theories about how they form (cf. Ref 8). Pools situated entirely within a rain-fed peat profile are characterized by low pH, low levels of primary production and nutrients, but high levels of dissolved organic matter that st...

Many degraded ecosystems are subject to restoration attempts, providing new opportunities to unravel the processes of ecological community assembly. Restoration of previously drained northern peatlands, primarily to promote peat and carbon accumulation, has created hundreds of thousands of new open water pools. We assessed the potential benefits of this wetland restoration for aquatic biodiversity, and how communities reassemble, by comparing pool ecosystems in regions of the UK Pennines on intact (never drained) versus restored (blocked drainage-ditches) peatland. We also evaluated the conceptual idea that comparing reference ecosystems in terms of their compositional similarity to null assemblages (and thus the relative importance of stochastic versus deterministic assembly) can guide evaluations of restoration success better than analyses of community composition or diversity. Community composition data highlighted some differences in the macroinvertebrate composition of restored pools compared to undisturbed peatland pools, which could be used to suggest that alternative end-points to restoration were influenced by stochastic processes. However, widely used diversity metrics indicated no differences between undisturbed and restored pools. Novel evaluations of restoration using null models confirmed the similarity of deterministic assembly processes from the national species pool across all pools. Stochastic elements were important drivers of between-pool differences at the regional-scale but the scale of these effects was also similar across most of the pools studied. The amalgamation of assembly theory into ecosystem restoration monitoring allows us to conclude with more certainty that restoration has been successful from an ecological perspective in these systems. Evaluation of these UK findings compared to those from peatlands across Europe and North America further suggests that restoring peatland pools delivers significant benefits for aquatic fauna by providing extensive new habitat that is largely equivalent to natural pools. More generally, we suggest that assembly theory could provide new benchmarks for planning and evaluating ecological restoration success.

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Saturnella saturnus was discovered in March 2014 in open-water pools on blanket peatland at the Moor House -Upper Teesdale National Nature Reserve, straddling Cumbria and County Durham in NE England. This is the first record for the British Isles of a little-known alga recorded previously only from a few peat bog areas, mainly in mainland Europe. The literature is reviewed and new observations presented on its morphology and reproduction based on LM examination of living cells. New observations on the chloroplast structure and cytoplasmic inclusions (especially oil droplets) are discussed in relation to the findings of earlier studies. Doubt attaches as whether it is a chlorophyte or a xanthophyte and the identity of small spherical inclusions been frequently interpreted as autospores. It occurs in Upper Teesdale in pools that are small, relatively newly formed and mostly well-oxygenated. Also discussed is its relationship to Trochiscia, another coloniser of peatland pools.Photographic images are presented for the first time and comments made on its ecology in the context of blanket bog conservation projects and apparent rarity.