Atmospheric nitrogen (N) deposition is a global and increasing threat to biodiversity and ecosystem function. Much of our current understanding of N deposition impacts comes from field manipulation ...studies, although interpretation may need caution where simulations of N deposition (in terms of dose, application rate and N form) have limited realism. Here, we review responses to simulated N deposition from the UKREATE network, a group of nine experimental sites across the UK in a diversity of heathland, grassland, bog and dune ecosystems which include studies with a high level of realism and where many are also the longest running globally on their ecosystem type. Clear responses were seen across the sites with the greatest sensitivity shown in cover and species richness of bryophytes and lichens. Productivity was also increased at sites where N was the limiting nutrient, while flowering also showed high sensitivity, with increases and declines seen in dominant shrub and forb species, respectively. Critically, these parameters were responsive to some of the lowest additional loadings of N (7.7–10 kg ha−1 yr−1) showing potential for impacts by deposition rates seen in even remote and ‘unpolluted’ regions of Europe. Other parameters were less sensitive, but nevertheless showed response to higher doses. These included increases in soil %N and ‘plant available’ KCl extractable N, N cycling rates and acid–base status. Furthermore, an analysis of accumulated dose that quantified response against the total N input over time suggested that N impacts can ‘build up’ within an ecosystem such that even relatively low N deposition rates can result in ecological responses if continued for long enough. Given the responses have important implications for ecosystem structure, function, and recovery from N loading, the clear evidence for impacts at relatively low N deposition rates across a wide range of habitats is of considerable concern.
Restoration of eroded blanket peatlands through revegetation and gully blocking is observed to also deliver significant natural flood management (NFM) benefits (reduce and delay floodpeaks). But ...there is a lack of clear understanding regarding how different catchment processes interact/counteract under each intervention scenario. We seek to provide more insight by rigorously calibrating TOPMODEL rainfall‐runoff model to different experimental catchments each representing an intervention scenario. Through numerical experimentation with the calibrated parameters, we estimate the impact‐magnitude of different processes. Our findings confirm the NFM benefits of these restoration‐focused interventions. In both interventions and in our largest storms, both the delay and reduced floodpeaks are primarily due to surface roughness reducing the floodwave speed thus thickening the overland flow; we conceptualize this as an increase in a “kinematic storage.” Impact of gully blocking in increasing kinematic storage is very significant and comparable to that of revegetation alone. Interventions' impact on “static storage” (interception + ponding + evapotranspiration) becomes important for smaller storms. Although interventions always increase lag times, they can be less effective in reducing peak magnitude when maximum rainfall intensity is sustained for durations longer than mean catchment delay. We propose two approaches to further increase catchment's static and kinematic storage. Finally, while our field‐scale numerical study contributes to the evidence‐base for NFM's effectiveness, it also provides a basis for modeling these interventions in the future. Such catchment‐scale numerical studies are necessary to extend our findings to spatial scales where flooding can cause socioeconomic damage, and to provide a tool for optimizing the distributed configuration of these interventions.
Key Points
Blanket peat restoration interventions significantly reduce flood risk to the downstream communities at risk
Revegetation and gully blocking of eroded blanket peat reduces flood risk primarily through increased surface roughness and not storage
Impact of gully blocking in reducing increasing “kinematic” surface storage is very significant and equivalent to revegetation alone
Parasitic plants have major impacts on plant community structure through their direct negative influence on host productivity and competitive ability. However, the possibility that these parasites ...may also have indirect impacts on community structure (via the mechanism of nutrient-rich litter input) while long hypothesized, has remained unsupported until now.
Using the hemiparasite Rhinanthus minor, we established experimental grassland mesocosms to quantify the impacts of Rhinanthus litter and parasitism across two soil fertility levels. We measured the biomass and tissue nutrient concentration of three functional groups within these communities to determine their physiological response to resource abstraction and litter input by the parasite.
We show that Rhinanthus alters the biomass and nutrient status of co-occurring plants with contrasting effects on different functional groups via the mechanism of nutrient-rich litter input. Critically, in the case of grass and total community biomass, this partially negates biomass reductions caused directly by parasitism.
This demonstrates that the influence of parasitic plant litter on plant community structure can be of equal importance to the much-reported direct impacts of parasitism. We must consider both positive indirect (litter) and negative direct (parasitism) impacts of parasitic plants to understand their role in structuring plant communities.
Peatland restoration practitioners are keen to understand the role of drainage via natural soil pipes, especially where erosion has released large quantities of fluvial carbon in stream waters. ...However, little is known about pipe‐to‐stream connectivity and whether blocking methods used to impede flow in open ditch networks and gullies also work on pipe networks. Two streams in a heavily degraded blanket bog (southern Pennines, UK) were used to assess whether impeding drainage from pipe networks alters the streamflow responses to storm events, and how such intervention affects the hydrological functioning of the pipe network and the surrounding peat. Pipeflow was impeded in half of the pipe outlets in one stream, either by inserting a plug‐like structure in the pipe‐end or by the insertion of a vertical screen at the pipe outlet perpendicular to the direction of the predicted pipe course. Statistical response variable η2 showed the overall effects of pipe outlet blocking on stream responses were small with η2 = 0.022 for total storm runoff, η2 = 0.097 for peak discharge, η2 = 0.014 for peak lag, and η2 = 0.207 for response index. Both trialled blocking methods either led to new pipe outlets appearing or seepage occurring around blocks within 90 days of blocking. Discharge from four individual pipe outlets was monitored for 17 months before blocking and contributed 11.3% of streamflow. Pipe outlets on streambanks with headward retreat produced significantly larger peak flows and storm contributions to streamflow compared to pipe outlets that issued onto straight streambank sections. We found a distinctive distance‐decay effect of the water table around pipe outlets, with deeper water tables around pipe outlets that issued onto straight streambanks sections. We suggest that impeding pipeflow at pipe outlets would exacerbate pipe development in the gully edge zone, and propose that future pipe blocking efforts in peatlands prioritize increasing the residence time of pipe water by forming surface storage higher up the pipe network.
Blocking of pipe outlets in a heavily degraded UK blanket bog led to new pipe outlets appearing or seepage occurring around blocks within 90 days of blocking. Two pipes at head locations contributed more to streamflow compared to two pipes at edge locations, altogether they accounted for 11.3 % of streamflow. The degree of water‐table drawdown in gully edges is thought to relate to piping activity. Peatland practitioners should consider control measures that reduce pipeflow further upslope of pipe outlets.
Over the past 15 years there has been a proliferation of projects aiming to restore the structure and function of UK upland blanket mires, primarily by revegetation of bare peat and the blocking of ...erosion gullies. These restoration measures have potential to alter stormflow responses and contribute to Natural Flood Management, but their impacts on storm hydrographs are poorly quantified. This paper reports a before-after-control-intervention (BACI) study from three experimental headwater micro-catchments in the South Pennines (UK) representing the first rigorous experimental assessment of the impact of blanket peat restoration on catchment runoff. We evaluate the hydrological impacts of two standard restoration interventions; revegetation of bare peat, and revegetation of bare peat with additional gully blocking. Following revegetation there was a significant decrease in depth to water table and an increase in the prevalence of hillslope overland flow production. There were no significant changes in storm runoff coefficient following either restoration treatment. Storm hydrographs following revegetation had significantly longer lag times (106% increase relative to the control), reduced peak flows (27% decrease relative to the control), and attenuated hydrograph shapes. With the addition of gully blocking the effect is almost doubled. Lag times increased by a further 94% and peak flows reduced by an additional 24% relative to the control. We argue that the primary process controlling the observed changes in storm hydrograph behaviour is retardation of overland stormflow due to increased surface roughness. The significant changes to lag times and peak flow provide evidence that the restoration of degraded headwater peatlands can contribute to Natural Flood Management and the reduction of downstream flood risk, subject to wider catchment scale effects and sub-catchment storm hydrograph synchronicity. Keywords: Flood risk management, Natural flood management, Re-vegetation, Gully blocking, Water tables, Peatland hydrology
Air pollutants are recognised as important agents of ecosystem change but few studies consider the effects of multiple pollutants and their interactions. Here we use ordination, constrained cluster ...analysis and indicator value analyses to identify potential environmental controls on species composition, ecological groupings and indicator species in a gradient study of UK acid grasslands. The community composition of these grasslands is related to climate, grazing, ozone exposure and nitrogen deposition, with evidence for an interaction between the ecological impacts of base cation and nitrogen deposition. Ozone is a key agent in species compositional change but is not associated with a reduction in species richness or diversity indices, showing the subtly different drivers on these two aspects of ecosystem degradation. Our results demonstrate the effects of multiple interacting pollutants, which may collectively have a greater impact than any individual agent.
► Ozone exposure, N and base cation deposition modify UK acid grassland composition. ► Ozone influences community composition without reducing species richness. ► Nitrogen and base cation deposition have interacting impacts. ► Distinct species responses to pollutants suggest potential for bioindication.
Ozone exposure and nitrogen deposition have distinct but additive impacts on the plant communities of British acid grasslands.
Introduction
What is the rate of injecting patients with shoulder corticosteroid injections to alleviate excessive stiffness and pain within 6 months after shoulder surgery?
Methods
Retrospective ...10-year review of a shoulder surgeon’s practice. Participants included 754 patients who had 945 non-arthroplasty shoulder surgeries. Outcome measures included the rate of injections, diagnoses, patient characteristics, and efficacy via questionnaire.
Results
Approximately one in five patients received a subacromial and/or glenohumeral corticosteroid injection. Over 95% of patients stated that the injections helped reduce shoulder pain and increased function 6 weeks post-injection. Twenty-two percent of cases (208/945) received glenohumeral and/or subacromial injections. The 208 injected cases had these diagnoses: rotator cuff tear (28% of injected patients), subacromial impingement (20%), glenohumeral instability (16%), subacromial impingement with acromioclavicular osteoarthritis (10%), adhesive capsulitis (7%), SLAP lesion (5%), biceps tendinopathy (3%), glenohumeral instability with subacromial impingement (3%), proximal humerus fracture (2%), calcific tendinitis (2%), and less common conditions (4%). Diagnoses among those with the highest rates of injected patients per diagnosis included: SLAP lesions (40%), calcific tendinitis (40%), adhesive capsulitis (29%), subacromial impingement (28%), proximal humerus fracture (24%), rotator cuff tear (19%), and glenohumeral instability (16%). Significant differences (
p
< 0.03) were found between patients who did and did not receive injections with respect to age (more likely younger patients with cuff tear) and sex (more likely female with subacromial impingement and instability) but not for diabetes or arthroscopic vs. open procedures.
Conclusion
This is the first study to establish the rates of postoperative shoulder corticosteroid injections within the first 6 months after various non-arthroplasty shoulder surgeries for patients with high pain/stiffness. These data will be useful for establishing guidelines for using corticosteroid injections along with physiotherapy.
Deposition of reactive nitrogen (N) compounds has the potential to cause severe damage to sensitive soils and waters, but the process of 'nitrogen saturation' is difficult to demonstrate or predict. ...This study compares outputs from a simple carbon-nitrogen model with observations of (1) regional-and catchment-scale relationships between surface water nitrate and dissolved organic carbon (DOC), as an indicator of catchment carbon (C) pool; (2) inter-regional variations in soil C/N ratios; and (3) plot scale soil and leachate response to long-term N additions, for a range of UK moorlands. Results suggest that the simple model applied can effectively reproduce observed patterns, and that organic soil C stores provide a critical control on catchment susceptibility to enhanced N leaching, leading to high spatial variability in the extent and severity of current damage within regions of relatively uniform deposition. Results also support the hypothesis that the N richness of organic soils, expressed as C/N ratio, provides an effective indicator of soil susceptibility to enhanced N leaching. The extent to which current C/N is influenced by N deposition, as opposed to factors such as climate and vegetation type, cannot be unequivocally determined on the basis of spatial data. However, N addition experiments at moorland sites have shown a reduction in organic soil C/N. A full understanding of the mechanisms of N-enrichment of soils and waters is essential to the assessment of current sensitivity to, and prediction of future damage from, globally increasing reactive nitrogen deposition.
Cyclic RGD-containing functionalized azabicycloalkane peptides were synthesized with the aim of developing high-affinity selective integrin ligands as carriers for therapeutic and diagnostic ...purposes. Herein we describe the synthesis and in vitro screening of these RGD derivatives, as well as the determination of their conformational properties in solution by spectroscopic and computational methods. Docking studies with the X-ray crystal structure of the extracellular domain of integrin alpha(v)beta(3) were also performed to elucidate the structural binding requirements and to rationalize the biological results. One compound in particular was found to be the best alpha(v)beta(3) integrin binder (IC(50)=53.7 nM) among the new functionalized RGD cyclic peptides, thus emerging as a promising candidate for covalent bonding and selective homing of useful functional units.
1. Upland moorlands are an extensive semi-natural resource, frequently burned either through management or uncontrolled outbreaks of fire. These systems are often situated in areas receiving high ...levels of atmospheric nitrogen (N) deposition, yet the effects of burning combined with high N deposition on ecosystem N pools and N leaching to surface waters are unknown. 2. A management burn was applied to an upland Calluna vulgaris moor which contained a set of long-term experimental plots treated with simulated increased N deposition at rates of +0, +40, +80 and +120 kg ha⁻¹ year⁻¹. Leaching losses of total dissolved inorganic N (TDNin) and dissolved organic N (DON) from organic and mineral soil horizons and the N pools in these horizons, as well as in litter and vegetation, were compared before and after the burn. 3. The results showed that leaching of TDNin and DON from both soil horizons increased in a 6-month period after the burn, with leaching of TDNin remaining elevated 2-3 years later. N pools in the deeper mineral layer of the soil also increased after the burn. Increasing long-term N additions magnified the burn effect on leaching losses but lessened the burn effect on the N pools in the mineral layer. In the +40 N addition plots, the amount of N removed in burning vegetation was of an equivalent size to the amount of additional N retained within the system. 4. Synthesis: These results suggest that burning approximately every 10 years may be effective in removing N retained in the system at N deposition rates up to 56 kg N ha⁻¹ year⁻¹. However, extensive burning of moorland or uncontrolled outbreaks of fire over wide areas may considerably exacerbate the threat of N loading to groundwater in areas where moors are more heavily N polluted, increasing the potential for acidification, eutrophication and brown water colouration. The data suggest that this is because the mineral horizon of upland moors receiving high N inputs has already been saturated with N such that increased downward percolation rates of N caused by the burn have risen above a threshold for immobilization (hence leading to more substantial post-burn increases in leaching of N).
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