Aerial photography collected with a multirotor drone reveals impact of Eurasian beaver reintroduction on ecosystem structure

doi: 10.1139/juvs-2015-0005Copyright © 2015 Canadian Science PublishingBeavers are often described as ecological engineers with an ability to modify the structure and flow of fluvial systems and create complex wetland environments with dams, ponds and canals. Consequently, beaver activity has implications for a wide range of environmental ecosystem services including biodiversity, flood risk mitigation, water quality and sustainable drinking water provision. With the current debate surrounding the reintroduction of beavers into the United Kingdom, it is critical to be able to monitor the impact of beavers upon the environment. This study presents the first proof of concept results showing how a lightweight hexacopter fitted with a simple digital camera can be used to derive orthophoto and digital surface model (DSM) data products at a site where beavers have recently been reintroduced. Early results indicate that analysis of the fine-scale (0.01 m) orthophoto and DSM can be used to identify impacts on the ecosystem structure including the extent of dams and associated ponds, and changes in vegetation structure due to beaver tree felling activity. Unmanned aerial vehicle data acquisition offers an effective toolkit for regular repeat monitoring at fine spatial resolution which is a critical attribute for monitoring rapidly-changing and difficult to access beaver-impacted ecosystems

Eurasian beaver activity increases water storage, attenuates flow and mitigates diffuse pollution from intensively-managed grasslands

This is the final version of the article. Available from Elsevier via the DOI in this record.Beavers are the archetypal keystone species, which can profoundly alter ecosystem structure and function through their ecosystem engineering activity, most notably the building of dams. This can have a major impact upon water resource management, flow regimes and water quality. Previous research has predominantly focused on the activities of North American beaver (Castor canadensis) located in very different environments, to the intensive lowland agricultural landscapes of the United Kingdom and elsewhere in Europe. Two Eurasian beavers (Castor fiber) were introduced to a wooded site, situated on a first order tributary, draining from intensively managed grassland. The site was monitored to understand impacts upon water storage, flow regimes and water quality. Results indicated that beaver activity, primarily via the creation of 13 dams, has increased water storage within the site (holding ca. 1000m(3) in beaver ponds) and beavers were likely to have had a significant flow attenuation impact, as determined from peak discharges (mean 30±19% reduction), total discharges (mean 34±9% reduction) and peak rainfall to peak discharge lag times (mean 29±21% increase) during storm events. Event monitoring of water entering and leaving the site showed lower concentrations of suspended sediment, nitrogen and phosphate leaving the site (e.g. for suspended sediment; average entering site: 112±72mgl(-1), average leaving site: 39±37mgl(-1)). Combined with attenuated flows, this resulted in lower diffuse pollutant loads in water downstream. Conversely, dissolved organic carbon concentrations and loads downstream were higher. These observed changes are argued to be directly attributable to beaver activity at the site which has created a diverse wetland environment, reducing downstream hydrological connectivity. Results have important implications for beaver reintroduction programs which may provide nature based solutions to the catchment-scale water resource management issues that are faced in agricultural landscapes.The Devon Beaver Project is led by Devon Wildlife Trust, monitored by the University of Exeter, and funded by Devon Wildlife Trust and Westland Countryside Stewards

Comparison of methods for evaluating the suitability of Vertisols for Gossypium hirsutum (Bt cotton) in two contrasting agro-ecological regions

This is the author accepted manuscript. The final version is available from Taylor and Francis (Routledge) via the DOI in this record.Cotton (Gossypium sp.) is a major crop grown under rainfed conditions in Vertisols and associated soils in semi-arid tropical (SAT) regions of Peninsular India. In recent years, cotton productivity has declined due to various biophysical factors including pest and diseases, seasonal water stress soil degradation and poor crop management practices. In this study, we compare two methods for evaluating the suitability of Vertisols for cotton in contrasting two agro-ecological regions viz., sub-humid moist (SHM) region and semi-arid dry(SAD) were characterized. Twelve cotton growing Vertisols (seven from SHM and five from SAD) were evaluated for their suitability for cotton cultivation using soil quality index (SQI) and modified Sys-FAO method. SQIs were calculated using the weighted additive index from transformed scores of selected indicators by principal component analysis. For Sys-FAO method both biophysical and soil characteristics were considered for suitability evaluation. We found that the soils of SHM region were moderately suitable for cotton cultivation with soil moisture as the major limiting factor, whereas the soils of SAD region are marginally suitable due to high exchangeable sodium percentage and poor hydraulic conductivity. From this, it may be concluded that the weighted SQI has better agreement with the cotton yield

Untangling the environmental drivers of gross primary productivity in African rangelands

This is the final version. Available on open access from Nature Research via the DOI in this recordData availability: All data used in this study are freely available and can be accessed in online repositories. The latest PML_V2 product39 is available through Google Earth Engine from https://github.com/gee-hydro/gee_PML. CHIRPS daily precipitation data38 is available at https://www.chc.ucsb.edu/data/chirps. ERA5-Land reanalysis data95 are available from the European Centre for Medium-Range Weather Forecasts at https://cds.climate.copernicus.eu/cdsapp#!/dataset/reanalysis-era5-land-monthly-means. The following MODIS datasets are available from the Land Processes Distributed Active Archive Center (LP DAAC): land cover classes90 (https://lpdaac.usgs.gov/products/mcd12q1v006/) and burned area96 (https://lpdaac.usgs.gov/products/mcd64a1v006/). The iSDAsoil dataset60 can be accessed at https://isda-africa.com/isdasoil. All datasets are also available through Google Earth Engine (Google account required) and are linked to in the Google Earth Engine repository detailed below. Processed data used for fitting the annual and multi-annual GAMs, as well as model output data used to generate Figs. 1–4, are available at https://doi.org/10.5281/zenodo.13294238.Code availability: Data preparation and analysis code is available at https://doi.org/10.5281/zenodo.7024961. The Google Earth Engine repository for data pre-processing can be accessed by registered Earth Engine users at https://code.earthengine.google.com/?accept_repo=users/guylomax01/africa_rangeland_ppt_gpp_analysis. Intermediate data pre-processing Earth Engine assets can also be accessed at https://code.earthengine.google.com/?asset=projects/ee-guylomax01/assets/africa_rangeland_precipitation_gpp.Precipitation variability is forecast to increase under climate change but its impacts on vegetation productivity are complex. Here, we use generalised additive models and remote sensing-derived datasets to quantify the effect of precipitation amount, distribution, and intensity on the gross primary productivity of dry rangelands across sub-Saharan Africa from 2000 to 2019 and differentiate these effects from other variables. We find that total precipitation is the primary driver of productivity, but that more variable rainfall has a small negative effect across vegetation types and rainfall regimes. Temperature and soil nitrogen also have strong effects, especially in drier rangelands. Shrublands and grasslands are more sensitive to environmental variability than savannas. Our findings support a model in which the main constraints on productivity are maintenance of soil moisture and minimisation of plant water stress. This highlights the risks of climate warming and increasing variability for productivity in water-limited grass and shrublands but suggests savannas may have greater resilience in Africa.Oppenheimer Programme in African Landscape Systems (OPALS)University of ExeterSarah TurvillOppenheimer Generations Research and ConservationEngineering and Physical Sciences Research Council (EPSRC)A. G. Leventis FoundationLeverhulme TrustAlan Turing InstituteEuropean Union Horizon 2020Cyprus Governmen

Allometric Relationships for Predicting Aboveground Biomass and Sapwood Area of Oneseed Juniper (Juniperus monosperma) Trees

This is the final version. Available from Frontiers Media via the DOI in this record. Across the semi-arid ecosystems of the southwestern USA, there has been widespread encroachment of woody shrubs and trees including Juniperus species into former grasslands. Quantifying vegetation biomass in such ecosystems is important because semi-arid ecosystems are thought to play an important role in the global land carbon (C) sink, and changes in plant biomass also have implications for primary consumers and potential bioenergy feedstock. Oneseed Juniper (J. monosperma) is common in desert grasslands and pinyon-juniper rangelands across the intermountain region of southwestern North America; however, there is limited information about the aboveground biomass (AGB) and sapwood area (SWA) for this species, causing uncertainties in estimates of C stock and transpiration fluxes. In this study, we report on canopy area, stem diameter, maximum height and biomass measurements from J. monosperma trees sampled from central New Mexico. Dry biomass ranged between 0.4 kg and 625 kg, and cross-sectional sapwood area was measured on n=200 stems using image analysis. We found a strong linear relationship between canopy area and AGB (r2 = 0.96), with a similar slope to that observed in other juniper species, suggesting that this readily measured attribute is well suited for upscaling studies. There was a 9% bias between different approaches to measuring canopy area, indicating care should be taken to account for these differences to avoid systematic biases. We found equivalent stem diameter (ESD) was a strong predictor of biomass, but that existing allometric models under-predicted biomass in larger trees. We found sapwood area could be predicted from individual stem diameter with a power relationship, and that tree-level SWA should be estimated by summing the SWA predictions from individual stems rather than ESD. Our improved allometric models for J. monosperma support more accurate and robust measurements of C storage and transpiration fluxes in Juniperus-dominated ecosystems.Natural Environment Research Council (NERC)U.S. National Science Foundatio

New zebrafish models of neurodegeneration

In modern biomedicine, the increasing need to develop experimental models to further our understanding of disease conditions and delineate innovative treatments has found in the zebrafish (Danio rerio) an experimental model, and indeed a valuable asset, to close the gap between in vitro and in vivo assays. Translation of ideas at a faster pace is vital in the field of neurodegeneration, with the attempt to slow or prevent the dramatic impact on the society's welfare being an essential priority. Our research group has pioneered the use of zebrafish to contribute to the quest for faster and improved understanding and treatment of neurodegeneration in concert with, and inspired by, many others who have primed the study of the zebrafish to understand and search for a cure for disorders of the nervous system. Aware of the many advantages this vertebrate model holds, here, we present an update on the recent zebrafish models available to study neurodegeneration with the goal of stimulating further interest and increasing the number of diseases and applications for which they can be exploited. We shall do so by citing and commenting on recent breakthroughs made possible via zebrafish, highlighting their benefits for the testing of therapeutics and dissecting of disease mechanisms

Treatment of acne with intermittent and conventional isotretinoin: a randomized, controlled multicenter study

Oral isotretinoin is the most effective choice in the treatment of severe acne. Application of isotretionin to acne has been expanded to treat those patients with less severe but scarring acne who are responding unsatisfactorily to conventional therapies. However, its use is associated with many side effects, some of which can result in very disastrous consequences. Data related with intermittent isotretinoin therapy is still limited. Our aim was to asses the efficacy and tolerability of two different intermittent isotretinoin courses and compare them with conventional isotretinoin treatment. In this multicenter and controlled study, 66 patients with moderate to severe cases were randomized to receive either isotretionin for the first 10 days of each month for 6 months (group 1), or each day in the first month, afterwards the first 10 days of each month for 5 months (group 2) or daily for 6 months (group 3). The drug dosage was 0.5 mg/kg/day in all groups. Patients were followed-up for 12 months. Efficacy values were evaluable for 22 patients in group 1, 19 patients in group 2, and 19 patients in group 3. Acne scores in each group were significantly lower at the end of treatment and follow-up periods (P < 0.001). When patients were evaluated separately as moderate (n = 31) and severe (n = 29), no statistically significant differences were obtained among the treatment protocols in patients with moderate acne. However, there was a significant difference between groups 1 and 3 to the response of the treatments in severe acne patients at the end of follow-up period (P = 0.013). The frequency and severity of isotretionin-related side effects were found to be lower in groups 1 and 2 compared with group 3. Intermittent isotretinoin may represent an effective alternative treatment, especially in moderate acne with a low incidence and severity of side effects. The intermittent isotretinoin can be recommended in those patients not tolerating the classical dosage

Location, location, location: considerations when using lightweight drones in challenging environments

Lightweight drones have emerged recently as a remote sensing survey tool of choice for ecologists, conservation practitioners and environmental scientists. In published work, there are plentiful details on the parameters and settings used for successful data capture, but in contrast there is a dearth of information describing the operational complexity of drone deployment. Information about the practices of flying in the field, whilst currently lacking, would be useful for others embarking on new drone-based investigations. As a group of drone-piloting scientists, we have operated lightweight drones for research in over 25 projects, in over 10 countries, and in polar, desert, coastal and tropical ecosystems, with many hundreds of hours of flying experience between us. The purpose of this paper was to document the lesser-reported methodological pitfalls of drone deployments so that other scientists can understand the spectrum of considerations that need to be accounted for prior to, and during drone survey flights. Herein, we describe the most common challenges encountered, alongside mitigation and remediation actions that increase the chances of safe and successful data capture. Challenges are grouped into the following categories: (i) pre-flight planning, (ii) flight operations, (iii) weather, (iv) redundancy, (v) data quality, (vi) batteries. We also discuss the importance of scientists undertaking ethical assessment of their drone practices, to identify and mitigate potential conflicts associated with drone use in particular areas. By sharing our experience, our intention is that the paper will assist those embarking on new drone deployments, increasing the efficacy of acquiring high-quality data from this new proximal aerial viewpoint.This work was supported by the Natural Environment Research Council [NE/K570009815], [NE/K500902/1] (to AMC), [NE/M016323/1] (to IHM-S), [NE/570009815] (to JPD) and the UK Technology Strategy Board [TS/K00266X/1] (to KA). JS and KA were partly supported by the European Space Agency contract No. 4000117644/16/NL/FF/gp

Strong Correspondence in Evapotranspiration and Carbon Dioxide Fluxes Between Different Eddy Covariance Systems Enables Quantification of Landscape Heterogeneity in Dryland Fluxes

This is the final version. Available on open access from Wiley via the DOI in this recordData Availability Statement: Post-processed half-hourly data from AmeriFlux systems are available at https://ameriflux.lbl.gov/login/?redirect_to=/data/download-data/ and the data from the low-frequency systems are archived with the NERC Environmental Information Data Centre (https://doi.org/10.5285/e96466c3-5b67-41b0-9252-8f8f393807d7). The code repository is archived on Zenodo (https://doi.org/10.5281/zenodo.4730586).The eddy covariance method is widely used to investigate fluxes of energy, water, and carbon dioxide at landscape scales, providing important information on how ecological systems function. Flux measurements quantify ecosystem responses to environmental perturbations and management strategies, including nature-based climate-change mitigation measures. However, due to the high cost of conventional instrumentation, most eddy covariance studies employ a single system, limiting spatial representation to the flux footprint. Insufficient replication may be limiting our understanding of ecosystem behavior. To address this limitation, we deployed eight lower-cost eddy covariance systems in two clusters around two conventional eddy covariance systems in the Chihuahuan Desert of North America for a period of 2 years. These dryland settings characterized by large temperature variations and relatively low carbon dioxide fluxes represented a challenging setting for eddy covariance. We found very good closure of energy and water balance across all systems (within ±9% of unity). We found very good correspondence between the lower-cost and conventional systems' fluxes of sensible heat (with concordance correlation coefficient (CCC) of ≥0.87), latent energy (evapotranspiration; CCC ≥ 0.89), and useful correspondence in the net ecosystem exchange ((NEE); with CCC ≥ 0.4) at the daily temporal resolution. Relative to the conventional systems, the low-frequency systems were characterized by a higher level of random error, particularly in the NEE fluxes. Lower-cost systems can enable wider deployment affording better replication and sampling of spatiotemporal variability at the expense of greater measurement noise that might be limiting for certain applications. Replicated eddy covariance observations may be useful when addressing gaps in the existing monitoring of critical and underrepresented ecosystems and for measuring areas larger than a single flux footprint.Natural Environment Research Council (NERC)National Science Foundation (NSF)Department of EnergyOppenheimer Programme in African Landscape System

Search for CP violation in D+→ϕπ+ and D+s→K0Sπ+ decays

A search for CP violation in D + → ϕπ + decays is performed using data collected in 2011 by the LHCb experiment corresponding to an integrated luminosity of 1.0 fb−1 at a centre of mass energy of 7 TeV. The CP -violating asymmetry is measured to be (−0.04 ± 0.14 ± 0.14)% for candidates with K − K + mass within 20 MeV/c 2 of the ϕ meson mass. A search for a CP -violating asymmetry that varies across the ϕ mass region of the D + → K − K + π + Dalitz plot is also performed, and no evidence for CP violation is found. In addition, the CP asymmetry in the D+s→K0Sπ+ decay is measured to be (0.61 ± 0.83 ± 0.14)%