Application of palaeoecology for peatland conservation at Mossdale Moor, UK

In a recent discussion of research priorities for palaeoecology, it was suggested that palaeoecological data can be applied and used to inform nature conservation practice. The present study exemplifies this approach and was conducted on a degraded blanket mire in Yorkshire, UK, in collaboration with a field-based moorland restoration agency. High-resolution, multiproxy palaeoecological analyses on a peat core from Mossdale Moor reconstructed mid to late-Holocene vegetation changes. Humification, pollen, plant macrofossil and charcoal analyses carried out throughout the peat profile show marked changes in species composition and indicate their potential causes. Results suggest that human clearance in the Mesolithic–Neolithic transition may have initiated peat growth at Mossdale Moor, making this landscape ‘semi-natural’ in its origin. Further human-induced changes are identified at 1300 cal years BP, most likely clearance by fire, and between 20 and 0 cm depth where a substantial charcoal increase is interpreted as recent (<400 years) management practices using burning to encourage browse on the moor. The long-term ecological history of the moor, derived using palaeoecological techniques, will be used to inform conservation practice and to help set feasible targets for restoration and conservation at Mossdale Moo

Questioning the reliability of “ancient” woodland indicators: Resilience to interruptions and persistence following deforestation

Indicator species can provide invaluable insights into environmental conditions but robust empirical testing of their effectiveness is essential. Ancient woodland indicators (AWIs) are plant species considered indicative of sites that have been continuously wooded for a long period by virtue of poor dispersal ability and intolerance of non-woodland habitats. Many countries now utilise AWI species lists to classify ancient woodlands. Here we use a metastudy approach to test resilience of AWIs to interruptions and persistence following deforestation – and thus the robustness of using AWI lists – using a novel approach. We compare current AWI assemblage with woodland history based on pollen evidence at nine sites across the UK with a robustly-dated and spatially-precise palynological profile. Sites were split into: (1) proven continuous woodland; (2) previously interrupted woodland; and (3) previously but not currently wooded. Vegetation history was >1000 years at most sites. Assessment of ancientness using AWIs agreed with palynologically-proven ancient woodland at two sites, including a species-poor woodland of previously-uncertain age. However, four interrupted woodland sites and three clear-felled sites supported extensive AWI floristic communities. This suggests AWIs are resilient to interruptions, possibly by remaining in the seed bank longer than expected, and persistent following deforestation. Persistence might be due to other species (e.g. heathland plants) acting as pseudo-canopy or because some AWIs are more tolerant of non-woodland locations than previously thought. We conclude that use of floristic AWIs alone in defining ancient woodland should be reviewed, especially where status links to planning policy and conservation prioritisation. We suggest species on AWI lists be reviewed under expert and local guidance and a system of weighting species based on their strict or strong affinity solely with ancient woodland be developed. The use of multi-taxa indicators is recommended to allow stakeholders globally to make informed decisions about ancient woodland status

Understanding Spatiotemporal Variation in Richness and Rate of Within-Site Turnover for Vegetation Communities in Western Eurasia over the Last 4000 Years

Vegetation communities are intricate networks of co-occurring species. Logistical challenges in collecting primary data means research often utilises short-term data from restricted geographical areas. In this study, we examine spatiotemporal change in richness and turnover of vascular plants and bryophytes over the last 4000 years at 23 sites in western Eurasia using high-resolution palaeoecological data. We find support for the Latitudinal Diversity Gradient and Altitudinal Diversity Gradient in both the overall vegetation community (arboreal and non-arboreal species) and the shrub and herb sub-community (non-arboreal species only), as well as a significant temporal increase in the gradient of both relationships. There was a temporal increase in (alpha) richness; the rate of turnover was high but temporally consistent for the overall vegetation community and high but decreasing over time for the shrub and herb sub-community. The rate of change in turnover was affected by latitude (steeper negative relationship at higher latitudes) and altitude (steeper negative relationship at lower altitudes). The Diversity-Stability Hypothesis was supported: vegetation communities changed from “lower richness, higher turnover” historically to “higher richness, lower turnover” more recently. Causal mechanisms for these complex interlinked biogeographical patterns remain ambiguous, but likely include climate change, non-native introductions, increasing homogenisation of generalist taxa, landscape simplification, and anthropogenic disturbance. Further research into drivers of the spatiotemporal patterns revealed here is a research priority, which is especially important in the context of biodiversity decline and climate change

Informing innovative peatland conservation in light of palaeoecological evidence for the demise of Sphagnum imbricatum: the case of Oxenhope Moor, Yorkshire, UK

Actively growing mires have high conservation value and the potential to sequester carbon. However, drainage, burning, overgrazing and atmospheric pollution have led to depauperation of native flora and loss of peat at many peatland sites. In order to counteract such degradation, palaeoecological techniques can be applied and the data then used to inform nature conservation practice. The present study exemplifies this approach and was conducted on degraded blanket mire in Yorkshire, UK, in collaboration with a field-based moorland restoration agency. High-resolution, multiproxy palaeoecological analyses on a peat core from Oxenhope Moor were used to reconstruct Holocene vegetation changes spanning approximately the last 7000 years. Humification, pollen, plant macrofossil and charcoal analyses show distinct changes in species composition and indicate their potential causes. Human-induced changes identified at 2100 cal. BP are most likely to reflect deliberate clearance by fire. Sphagnum imbricatum disappears and is subsequently replaced by S. papillosum at ca. 1000 cal. BP, possibly due to drier conditions and competition between the two species. Increased human activity is identified since the Industrial Revolution where monocots and Eriophorum vaginatum increase, interpreted as a result of managed burning. It is intended that the long-term ecological history of the site, derived using palaeoecological techniques, will be used to inform conservation practice and can help set feasible targets for restoration and conservation. Specifically, encouraging a species mix that has pre-19th century longevity is suggested, including the specific recommendation that translocation of S. imbricatum be explored experimentally at this site, with a view to ascertaining likely success elsewhere

Using palaeoecology to advise peatland conservation: An example from West Arkengarthdale, Yorkshire, UK

Globally, peatlands are regarded as important carbon stores and their conservation essential for ensuring continuation of terrestrial carbon storage. Numerous peatlands in particular regions of Europe have been degraded by drainage, burning, extraction, overgrazing and pollution in recent decades, often leading to erosion, loss of peat mass and a loss of a variety of flora. In the UK, some 90% of peatlands can be regarded as degraded. Implemented restoration schemes have been aimed at blocking drainage ditches, re-vegetating bare peat or changing the present vegetation assemblage to a more ‘desirable’ alternative. Here we use palaeoecological techniques to reconstruct the development of a blanket peatland through its entirety with a particular focus on recent land management practices and their impact on vegetation in order to determine and support restoration targets. Analysis at West Arkengarthdale, Yorkshire, UK, shows that the present vegetation is not characteristic and has only been present for c. 200 years. Peat has been developing at the site for approximately 6700 years with Sphagnum particularly abundant between 0–40 cm depth (present day—450 cal. BP) and 150–190 cm depth (c. 3200–3900 cal. BP) and seldom recorded elsewhere in the core. A very recent change in Sphagnum composition is seen towards the surface of the profile, with Sphagnum papillosum making up 100% of the identified Sphagnum in the last 50 years. Monocots, Poaceae, Rumex and Polytrichum commune increase with the beginning of the industrial revolution and an increase in charcoal fragments is indicative of increased pollution and managed burning to support grouse management. It is suggested that any intention to alter land management at the site to encourage a greater variety of Sphagnum species and a decrease in Calluna is in line with peatland development at the site over the past 450 years. This collaborative approach between research palaeoecologists and conservation agency staff has wider application elsewhere

Environmentally-realistic concentrations of anthelmintic drugs affect survival and motility in the cosmopolitan earthworm Lumbricus terrestris (Linnaeus, 1758)

Anthelmintic drugs are used to control intestinal parasitic worms in animals worldwide. Although generally effective in managing animal health, such treatment can introduce anthelminthic compounds to the wider environment as active ingredients and metabolites are often excreted. This can have detrimental effects on non-target species, especially when drugs are used excessively. Here, we examine the effects that two environmentally-realistic concentrations of four anthelminthics have on the common earthworm Lumbricus terrestris (Linnaeus, 1758), a species with a cosmopolitan distribution and that is often vital in maintaining functional edaphic ecosystems. The drugs were ivermectin (0.502 and 2.511 mg kG−1 active ingredient), fenbendazole (0.309 and 1.547 mg kG−1), pyrantel (79.480 and 397.400 mg kG−1), and praziquantel (2.299 and 11.499 mg kG−1): these concentrations were typical of soils where pasture grazed by animals treated with anthelminthics. Both lethal effects (mortality) and sub-lethal effects (motility) were considered. Earthworms exposed to fenbendazole and praziquantel over a 12-week period experienced high mortality (55.0% and 32.5%, respectively). Mortality rates among earthworms exposed to pyrantel and ivermectin were much lower (2.5% and 7.5%, respectively). However, earthworms exposed to pyrantel and ivermectin suffered decreased motility (time to burrow into substrate when exposed to heat and light) relative to a control group. Burrowing times were up to 40% longer for pyrantyl-exposed earthworms and 28% longer for ivermectin-exposed earthworms. For both drugs, the magnitude of the effect increased as concentration increased; all differences were statistically significant. There was little effect of fenbendazole and praziquantel on motility. Based on this study, which is seemingly the first to examine effects of ivermectin/fenbendazole on earthworm motility and the first to consider any effects of praziquantel/pyrantel, we conclude that environmentally-realistic concentrations of all four anthelmintics have sub-lethal (pyrantel and ivermectin) or lethal (fenbendazole and praziquantel) effects on a vital keystone species. Methods to reduce carry-over effects in ecologically-important, non-target, organisms should be urgently sought and care should be taken not to use anthelminthics routinely without first testing helminth burden to determine whether there is clinical need

Exploring the prevalence and diversity of pollen carried by four species of migratory Old World warbler (Sylvioidea) on arrival in the UK

Capsule Pollen encrusted around the bill of migrating warblers can reveal marked differences in foraging ecology between bird species. Aims To examine patterns of the prevalence and diversity of pollen in four species of warbler, and explore the potential of pollen to act as an indicator of recent foraging behaviour. Methods By isolating pollen from bill encrustations using laboratory palynological techniques and identification by light microscopy, we examined variation in the prevalence of the five most common pollen taxa, and variation in pollen assemblages in four species of warbler arriving on the south coast of England. Results All samples contained abundant pollen, with 19 floral taxa identified. Sylvia warblers tended to carry Prunus and Citrus pollen, while Phylloscopus warblers mainly carried Eucalyptus pollen. Pollen assemblages varied markedly between bird species. Conclusion Commercial and garden flowering trees are an important resource for migrating warblers. Pollen may be such a valuable resource that flowering plants might be included in the conservation management of stopover sites. The use of pollen to resolve migratory routes may be problematic however, requiring detailed knowledge of both the distribution and flowering phenology of plants en route

Differential retention of pollen grains on clothing and the effectiveness of laboratory retrieval methods in forensic settings

Forensic palynology has been important in criminal investigation since the 1950s and often provides evidence that is vital in identifying suspects and securing convictions. However, for such evidence to be used appropriately, it is necessary to understand the factors affecting taphonomic variability (i.e. the variability in the fate of pollen grains before they are found during forensic examination). Here, we test the relative amount of pollen retained on clothing after a period of simulated light or heavy wear based on pollen and fabric characteristics. We also test the efficiency of forensic laboratory protocols for retrieving pollen from fabrics for analysis. There was no statistically significant difference in retention of fresh or dried pollen on any fabric type. There was a substantial difference in pollen retention according to wear intensity, with considerably more pollen being retained after light wear than after heavy wear. Pollen from insect-pollinated species was retained at higher concentrations than pollen from wind-pollinated species. This pattern was consistent regardless of wear intensity but pollination type explained more of the variability in pollen retention after light wear. Fabric type was significantly related to pollen retention, but interacted strongly with plant species such that patterns were both complex and highly species-specific. The efficiency of removing pollen with the standard washing protocol differed substantially according to plant species, fabric type, and the interaction between these factors. The average efficiency was 67.7% but this ranged from 21% to 93%, demonstrating that previous assumptions on the reliability of the technique providing a representative sample for forensic use should be reviewed. This paper highlights the importance of understanding pollen and fabric characteristics when creating a pollen profile in criminal investigations and to ensure that evidence used in testimony is accurate and robust

Sweet Chestnut (Castanea Sativa Mill.) in Britain: Re-assessment of its Status as a Roman Archaeophyte

The Roman period sees the introduction of many new plants and animals into Britain, with a profound impact on people’s experience of their environment. Sweet chestnut is considered to be one such introduction, for which records of sweet chestnut wood and charcoal from archaeological excavations of Romano-British period contexts have been used as evidence. This paper reviews the records for sweet chestnut in Britain pre-A.D. 650, by critically evaluating original excavation reports and examining archived specimens. This review re-assesses the original identifications of sweet chestnut and/or their dating and concludes that most of the evidence that justified sweet chestnut’s status as a Roman archaeophyte is untenable. The review emphasises the importance of securely identifying and directly dating plant material and of long-term curation by museums and archives