Peatlands provide important ecosystem services including carbon storage and biodiversity conservation. Remote sensing shows potential for monitoring peatlands, but most off-the-shelf data products ...are developed for unsaturated environments and it is unclear how well they can perform in peatland ecosystems. Sphagnum moss is an important peatland genus with specific characteristics which can affect spectral reflectance, and we hypothesized that the prevalence of Sphagnum in a peatland could affect the spectral signature of the area. This article combines results from both laboratory and field experiments to assess the relationship between spectral indices and the moisture content and gross primary productivity (GPP) of peatland (blanket bog) vegetation species. The aim was to consider how well the selected indices perform under a range of conditions, and whether Sphagnum has a significant impact on the relationships tested. We found that both water indices tested normalized difference water index (NDWI) and floating water band index (fWBI) were sensitive to the water content changes in Sphagnum moss in the laboratory, and there was little difference between them. Most of the vegetation indices tested the normalized difference vegetation index (NDVI), enhanced vegetation index (EVI), structure insensitive pigment index (SIPI), and chlorophyll index (CIm) were found to have a strong relationship with GPP both in the laboratory and in the field. The NDVI and EVI are useful for large-scale estimation of GPP, but are sensitive to the proportion of Sphagnum present. The CIm is less affected by different species proportions and might therefore be the best to use in areas where vegetation species cover is unknown. The photochemical reflectance index (PRI) is shown to be best suited to small-scale studies of single species.
Afforestation of formerly open landscapes can transform mammalian predator communities, potentially impacting prey species like ground‐nesting birds. In Scotland's Flow Country, a globally important ...peatland containing many forestry plantations, earlier studies found reduced densities of breeding waders on open bogs, when forestry plantations were present within 700 m. One plausible explanation for this pattern is mammalian predation. We tested whether mammalian predator indices, based on scats (feces), differed between (1) open bog, forestry plantations, and former plantations being restored as bog (“restoration” habitats); (2) restoration habitats of different ages; and (3) open bogs with differing amounts of nearby forestry. We measured summer scat density and size over 14 years in 26 transects 0.6–4.5 km in length, collecting data during 93, 96, and 79 transect‐years in bog, forestry, and restoration habitats respectively. In forestry, scat density increased eightfold, reaching values ~6 times higher than those of bogs. On open bogs with over 10% forestry within 700 m, scat densities were 2.9 times higher than on open bogs with less forestry nearby. Results support the hypothesis that mammalian predators might be responsible for the low densities of breeding waders close to forests, on adjacent open bogs. In restoration habitats, scat densities rose 6–10 years after felling but fell to levels similar to open bogs in older restoration habitats, supporting restoration management as a means of reducing mammalian predator activity/abundance. We urge caution around decisions to establish forestry plantations in open landscapes of high biodiversity importance.
Questions: Does restoration management of a formerly afforested blanket bog lead to the vegetation, and the environmental conditions it indicates, becoming similar to intact bog? Location: A 147-ha ...blanket bog in Scotland's Flow Country, afforested in the 1980s but undergoing restoration since 1998. Methods: Vegetation in the restoration area was surveyed in nine, 1.6–6.4-ha plots, in 1998, 2003 and 2011. Each plot was matched to nearby plots that were either intact bog or remained afforested. Principal Response Curves were used to highlight the main axes of vegetation variation and test whether plant community trajectories in the restoration area differed from intact bog. The following restoration outcomes were assessed: floristic similarity to bog vegetation; and moisture, fertility and acidity, as inferred from vegetation using Ellenberg indicator values. Results: In the 6 years after restoration began, vegetation developed towards bog-like conditions. In the subsequent 8 years, overall vegetation change stalled, and spatial variability increased, reflecting diverging trajectories in wetter and drier parts of the site. Ellenberg's F-values implied significant re-wetting in the restoration area, reaching moisture levels similar to intact bog. Other restoration outcomes progressed in wetter microsites and areas (furrows and flat ground), but stalled in drier locations (plough-ridges and steeper slopes). Conclusions: Overall moisture conditions, as indicated by plants, have recovered. However, restoration progress has stalled in drier areas, where additional management may be needed. Long-term vegetation monitoring has helped clarify barriers to recovery and the management needed to overcome them. The value of such monitoring schemes in guiding restoration should be reflected in their wider implementation, within an adaptive management framework.
Recent climate predictions for the United Kingdom expect a nationwide shift towards drier and warmer summers, increasing the risk of more frequent and severe drought events. Such shifts in weather ...patterns impede functioning of global peatlands, especially rare intact blanket bogs abundant in Scotland and representing nearly a quarter of the UK's soil carbon. In this in situ study, carbon dioxide (CO2) fluxes from dominant peatland plant functional types (PFTs) such as Sphagnum spp., graminoids, ericoids and other key cover types (i.e., pools and bare peat) were measured and compared across upland and low‐lying blanket bog margins and centres, immediately before and during a summer drought in 2018, and over the subsequent year. During that period, most sites acted as net sources of CO2 to the atmosphere. Our results showed that net ecosystem exchange (NEE) was limited by water availability during the drought, with ericoid shrubs showing the highest drought resilience, followed by graminoids (which were still limited in GPP in 2019) and Sphagnum mosses. Diverging NEE estimates were observed across centre and margin areas of the blanket bogs, with highest variability across the upland site where signs of active erosion were visible. Overall, our study suggests that estimating growing season carbon fluxes from in situ peatland PFT and cover types can help us better understand global climate change impacts on the dynamics and trajectories of peatland C cycles.
Edge effects of native forest fragmentation have been well studied, but there are few studies of open‐ground habitats fragmented by plantation forests. We measure forestry edge effects on open‐ground ...breeding birds, following one of Europe's biggest and most controversial land‐use transformations. The ‘Flow Country’ of northern Scotland is one of the world's greatest expanses of blanket bog. It became fragmented by conifer forests planted in the late 20th century, and these now adjoin open peatlands protected under European conservation legislation. Detrimental edge effects on breeding birds were anticipated, but not apparent shortly after planting. Using survey data collected in 2003–2006, and logistic regression modelling, we tested whether breeding distributions of three wader species of international conservation concern, dunlin, European golden plover and common greenshank, were influenced by distance to forest edge, controlling for habitat and topography. All three species were more likely to occupy flatter, more exposed ground close to bog pools and were influenced by peatland vegetation structure. There was an additive and adverse effect of proximity to forest edge for dunlin and European golden plover, but not common greenshank. This effect was strongest within 700 m of forest edges. We used these results to predict which areas should benefit most from removal of adjacent forestry and so guide maintenance and restoration of the bird interests of the protected areas. Synthesis and applications. Edge effects of mature forestry on dunlin and golden plover are apparent over several hundred metres and are now being used to guide forest planning in northern Scotland. The scale of edge effect is broadly consistent with other avian studies in open‐ground habitats across Eurasia and North America, so buffer zones of this order are consistent with possible impacts of plantation forestry on open‐ground habitats of bird conservation interest. Given renewed interest in conifer afforestation as a climate change mitigation measure, an improved understanding of edge effects and the mechanisms through which they operate is vital to managing plantation forestry in ways that maintain open‐ground landscapes of high conservation value.
Natural disturbances, like those caused by fires or large herbivores, can strongly affect forest ecosystems. Managers can emulate such disturbance effects, for example, with prescribed fire or ...domestic livestock. This might benefit species of conservation importance, including capercaillie
Tetrao urogallus
. We tested this idea using two management trials in a Scots pine
Pinus sylvestris
forest in Scotland. One trial (blocked design with 25 replicates) in small plots (0.07 ha) tested the effects of prescribed burning or mowing alongside a control. The other compared cattle grazing in two large plots (6 ha and 14 ha) with a control. We measured capercaillie habitat quality indicators, namely, in both trials: cover of bilberry
Vaccinium myrtillus
; and in the burning and mowing trial: biomass of arthropods taken by capercaillie chicks, and capercaillie dung. Monitoring took place before treatments, and afterwards over a 12–13 year period. Bilberry cover increased following burning and mowing, peaking at 1.4 times control values, six years post-treatment. In one of the cattle plots, similar bilberry increases were recorded throughout the post-treatment period. However, the other cattle plot showed no such change, perhaps reflecting different competitive interactions among field layer plants. Capercaillie dung and spider biomass increased markedly in burnt and mown areas, and ant biomass just in burnt areas. Unexpectedly, bilberry also increased strongly in control areas of both trials, reflecting wider successional changes. Our results suggest that any of these techniques could be used to improve capercaillie habitat quality, but should be delivered alongside monitoring, so that their effects can be evaluated in particular contexts.
To evaluate the effect of respiratory scoring criteria on diagnosis and classification of sleep disordered breathing (SDB) in chronic heart failure (CHF).
Cross-sectional observational study.
Heart ...failure and general cardiology clinics at two London hospitals.
One hundred eighty stable patients with CHF and a median age of 69.6 y, 86% male.
SDB was diagnosed by polysomnography. The apnea-hypopnea index (AHI) was initially scored using a conservative hypopnea definition of a ≥ 50% decrease in nasal airflow with a ≥ 4% oxygen desaturation. The AHI was rescored with hypopnea defined according to the American Academy of Sleep Medicine (AASM) alternative scoring rule, requiring an associated ≥ 3% oxygen desaturation or arousal. SDB was defined as AHI ≥ 15/h. Diagnosis and classification of SDB as obstructive sleep apnea (OSA) or central sleep apnea (CSA) with each rule were compared. The effect of mixed apneas on classification of SDB as CSA or OSA was also investigated.
Median AHI increased from 9.3/h to 13.8/h (median difference 4.6/h) when the AASM alternative rule was used to score hypopneas. SDB prevalence increased from 29% to 46% with the alternative scoring rule (P < 0.001). Classification of SDB as OSA or CSA was not significantly altered by hypopnea scoring rules or the categorization of mixed apneas.
Hypopnea scoring rules can significantly influence the apnea-hypopnea index and diagnosis of sleep disordered breathing in chronic heart failure but do not alter the classification as obstructive sleep apnea or central sleep apnea. Standardization of hypopnea scoring rules is important to ensure consistency in diagnosis of sleep disordered breathing in chronic heart failure patients.
Sleep-disordered breathing (SDB) is under diagnosed in chronic heart failure (CHF). Screening with simple monitors may increase detection of SDB in a cardiology setting. This study aimed to evaluate ...the accuracy of heart rate variability analysis and overnight pulse oximetry for diagnosis of SDB in patients with CHF.
180 patients with CHF underwent simultaneous polysomnography, ambulatory electrocardiography and wrist-worn overnight pulse oximetry. SDB was defined as an apnoea-hypopnoea index ≥15/h. To identify SDB from the screening tests, the per cent very low frequency increment (%VLFI) component of heart rate variability was measured with a pre-specified cutoff ≥2.23%, and the 3% oxygen desaturation index was measured with a pre-specified cutoff >7.5 desaturations/h.
173 patients with CHF had adequate sleep study data; SDB occurred in 77 (45%) patients. Heart rate variability was measurable in 78 (45%) patients with area under the %VLFI receiver operating characteristic curve of 0.50. At the ≥2.23% cutoff, %VLFI sensitivity was 58% and specificity was 48%. The 3% oxygen desaturation index was measurable in 171 (99%) patients with area under the curve of 0.92. At the pre-specified cutoff of >7.5 desaturations/h, the 3% oxygen desaturation index had a sensitivity of 97%, specificity of 32%, negative likelihood ratio of 0.08 and positive likelihood ratio of 1.42. Diagnostic accuracy was increased using a cutoff of 12.5 desaturations/h, with sensitivity of 93% and specificity of 73%.
The high sensitivity and low negative likelihood ratio of the 3% oxygen desaturation index indicates that pulse oximetry would be of use as a simple screening test to rule out SDB in patients with CHF in a cardiology setting. The %VLFI component of heart rate variability is not suitable for detection of SDB in CHF.
The increased prevalence of obstructive sleep apnea (OSA) in congestive heart failure (CHF) may be associated with rostral fluid shift. We investigated the effect of overnight rostral fluid shift on ...pharyngeal collapsibility (Pcrit), pharyngeal caliber (APmean), and apnea‐hypopnea index (AHI) in CHF patients. Twenty‐three optimally treated systolic CHF patients were studied. Neck circumference was measured immediately prior to sleep in the evening and immediately after waking in the morning as a marker of rostral fluid shift. Pcrit was measured during sleep, early and late in the night. APmean was measured using acoustic reflection at the same times as neck circumference measurements. 15/23 CHF patients experienced an overnight increase in neck circumference; overall neck circumference significantly increased overnight (mean±SD, evening: 41.7 ± 3.2 cm; morning: 42.3 ± 3.1 cm; P = 0.03). Pcrit increased significantly overnight (early‐night: −3.8 ± 3.3 cmH2O; late‐night: −2.6 ± 3.0 cmH2O; P = 0.03) and APmean decreased (evening: 4.2 ± 1.3 cm2; morning: 3.7 ± 1.3 cm2; P = 0.006). The total AHI correlated with neck circumference (r = 0.4; P = 0.04) and Pcrit (r = 0.5; P = 0.01). APmean correlated with neck circumference (r = −0.47; P = 0.02). There was no significant change in AHI between the first and second half of the night (first‐half: 12.9 ± 12.4/h; second‐half: 13.7 ± 13.3/h; P = 0.6). Overnight rostral fluid shift was associated with increased pharyngeal collapsibility and decreased pharyngeal caliber during sleep in CHF patients. Rostral fluid shift may be an important mechanism of OSA in this patient group.
We investigated the effect of rostral fluid shift on pharyngeal collapsibility as a possible mechanism for obstructive sleep apnoea in heart failure patients. Overnight rostral fluid shift was accompanied by a decrease in pharyngeal calibre and an increase in pharyngeal collapsibility. Our findings show that overnight rostral fluid shift is associated with increased narrowing and collapsibility of the airway in heart failure patients.
Abstract
Restoring native woodlands to areas where they have been lost is a key element for tackling the nature and climate crises. Natural regeneration offers the potential to achieve this cheaply ...and at scale, but browsing ungulates like deer can inhibit this or alter the pattern of regeneration. This issue is particularly pronounced in the Scottish Highlands, a heavily deforested region with high deer numbers.
We describe the work of the 60,000 ha landscape restoration partnership, Cairngorms Connect, in speeding up natural woodland expansion. We use 30 years of regeneration monitoring to show a consistent, large‐scale expansion of native woodland, largely through natural regeneration alongside deer culling, without the use of fences. This was achieved across the partnership, despite differing management histories and land‐managing organisations (comprising two statutory agencies, one private landowner and one non‐governmental organisation).
During peak periods of woodland expansion, the area of new woodland (i.e. exceeding 100 trees per hectare) increased by 1.2%, 1.7%, 2.7% and 6.0% annually in the four landholdings' regeneration zones, equating to a total of approximately 164 ha annually of new woodland.
Natural regeneration is however patchy and hard to predict. Higher levels of management intervention may be needed to increase species that are rarer, more palatable or further from seed sources; we recommend long‐term field trials to inform this, such as those underway in Cairngorms Connect. Further research should develop techniques for remote sensing of woodland expansion, verified against field data and combined with the development of process‐based models to enable us to predict the outcomes of different management scenarios.
Synthesis and applications
. We show that collaborative deer management across multiple adjoining landholdings can achieve rapid landscape‐scale native woodland expansion with minimal need for planting or fencing. Our results show the power of monitoring regeneration directly, to inform deer management for an area. We demonstrate that by uniting over a shared vision, organisations with differing management approaches and histories can build understanding alongside landscape‐scale ecological restoration.
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