Are conservation actions reducing the threat to India's vulture populations?

Research Communications.-- et al.Veterinary use of the non-steroidal anti-inflammatory drug, diclofenac is responsible for the population collapse of resident vulture species in India. Conservation efforts, including a ban on veterinary diclofenac and the identification of a vulture-safe alternative (meloxicam), were introduced in 2006 in order to address the threat. Sampling of domesticated ungulate carcasses available to vultures in India was undertaken in three surveys prior to, around the time of, and 1-2 years after the ban in order to quantify the prevalence of diclofenac and meloxicam residues. A total of 1445, 1488 and 1251 liver tissue samples were collected from nine states and analysed with a validated LC-ESI/MS methodology. Overall diclofenac prevalence levels declined by almost a half over the three surveys, and there was an increase in meloxicam prevalence between the second and third surveys, although some states revealed little change. These surveys indicate that two of the key conservation actions to counter the threat faced by vultures - banning veterinary diclofenac and promoting meloxicam as a safe alternative - are beginning to take effect. However, because only a small proportion of diclofenac-contaminated carcasses is sufficient to cause vulture population declines, further efforts are needed to eliminate diclofenac from the food supply of India's vultures.The research was funded by the UK Government’s Darwin Initiative programme and by the Royal Society for the Protection of Birds, UK.Peer Reviewe

An objective frequency domain method for quantifying confined aquifer compressible storage using Earth and atmospheric tides

The groundwater hydraulic head response to the worldwide and ubiquitous atmospheric tide at 2 cycles per day (cpd) is a direct function of confined aquifer compressible storage. The ratio of the responses of hydraulic head to the atmospheric pressure change is a measure of aquifer barometric efficiency, from which formation compressibility and aquifer specific storage can be determined in situ rather than resorting to laboratory or aquifer pumping tests. The Earth tide also impacts the hydraulic head response at the same frequency, and a method is developed here to quantify and remove this interference. As a result, the barometric efficiency can be routinely calculated from 6-hourly hydraulic head, atmospheric pressure, and modeled Earth tide records where available for a minimum of 15 days duration. This new approach will be of critical importance in assessing worldwide problems of land subsidence or groundwater resource evaluation that both occur due to groundwater abstractio

Absence of CALR Mutations in Idiopathic Erythrocytosis Patients with Low Serum Erythropoietin Levels

International audienc

Hydraulic processes controlling recharge through glacial drift

The research aims to further the understanding of hydraulic processes governing recharge through glacial drift (superficial deposits) at a range of scales by investigating the Potford Brook catchment, Shropshire, UK. At the local scale (10s m to km), an original application of the electrical resistivity tomography (ERT) method and coring have enabled a better understanding of the drift architecture and conceptual hydraulic models of recharge to be derived. At the site scale (cm to 10s m) hydraulic and hydrochemical/tracer test data suggest that recharge occurs through preferential pathways in variably saturated till. Furthermore, near-vertical hydraulically active fractures, thought to result from desiccation/freeze thaw processes and infilled with material derived from clasts in the till, have been observed. This is some of the first evidence of hydraulically significant fracturing in British glacial till. The permeability of a 6 m thick till deposit is thus approximately one order of magnitude greater than the matrix permeability. Potential travel times of contaminants to the till water table (<2 mbgl) may be as high as 1 cm/d. In glaciofluvial deposits, preferential flow is also shown to be significant and lateral flow is caused by perching on underlying glaciolacustrine materials. The vertical flow to the sandstone aquifer through the glaciolacustrine deposits has been shown, for the first time, to be just a few mm/a. Aquifer recharge may be enhanced locally in areas of patchy till/glaciolacustrine deposits due to the delayed infiltration of lateral subsurface flows and runoff. Temperature effects on the resistivity of the shallow subsurface can be very significant complicating the interpretation of time series ERT images. The results have important implications for sustainable catchment management and aquifer vulnerability

Understanding the potential of groundwater teleconnections to forecast hydrological extremes

Groundwater teleconnections is a growing area of research seeking to detect and understand relationships between wide-scale ocean-atmosphere oscillations and groundwater response. Such relationships can yield important predictive information on groundwater variability and extremes for future years or decades. However, due to the complex non-linear relationships between large-scale climate systems and regional to local-scale rainfall, ET and groundwater; detecting wide-scale evidence of such groundwater teleconnections, and their influence on drought and groundwater flooding, has been difficult. Here, we present the biggest groundwater teleconnection study to date, using an improved wavelet-based methodology to (1) quantify the strength of annual to multi-annual cyclical behaviour in monthly groundwater levels in 60 UK reference boreholes; (2) Analyse rainfall and ET to assess the contribution of teleconnections for these periodicities, and (3) evaluate how indicative these cycles are of groundwater extremes in the UK. Our results are the first to quantify the relative strength of seasonal and extra-seasonal variance in monthly groundwater levels, indicating that �7-year cycles in Chalk (limestone) and sandstone groundwater levels are often comparable to seasonality in defining total groundwater level variability.We demonstrate that the �7 year periodicity in groundwater results from a rainfall-based teleconnection with the North Atlantic Oscillation; documenting a clear alignment with every major recorded instance of groundwater drought (and recent instances of groundwater flooding) in the UK. An understanding that the severity of groundwater drought, and to some extent flooding, is enhanced on a 7-year cycle, produced through a teleconnection, provides significant opportunity for forecasting of future groundwater extremes. This understanding will becoming increasingly critical given the expected increased pressure on groundwater resources as a result of climate change, particularly in the UK and Europe

The Impact of Convection-Permitting Rainfall on the Dryland Water Balance

In drylands, rainfall is typically delivered during short-lived and localised convective storms, the characteristics of which determine how water is partitioned into different terrestrial stores. However, rainfall datasets used in hydrological modelling and assessments of water resources are typically derived from climate models that are too coarse to represent convective processes occurring at scales smaller than the model. In this paper, we quantify the impact of climate model representation of convection on the simulated water balance at four locations in the Horn of Africa: a humid site in the Ethiopian Highlands, a semi-arid site in southern Kenya, an arid site in eastern Ethiopia, and a hyper-arid site in northern Somalia. We benchmark the novel pan-Africa convection-permitting climate model (CP4A) and its parameterised counterpart (P25) against high-resolution satellite-derived gridded datasets of rainfall (IMERG) and PET (hPET). The comparison shows that explicitly resolving convection improves the characterisation of rainfall frequency, intensity, and the relative contribution of low vs high-intensity rainfall to annual totals. We also demonstrate that the representation of convection can impact model PET. However, differences in PET between CP4A and P25 are more muted relative to rainfall, and both can capture seasonal and diurnal PET dynamics. To establish how climate model representation of convection can impact hydrology, we then ran a series of one-dimensional hydrological model experiments along an aridity gradient across the Horn of Africa using Hydrus 1-D, where at each of our four sites, Hydrus was driven by rainfall and PET from CP4A and P25 (and hPET). The &lsquo;drizzle&rsquo; bias in P25 means that when rainfall is propagated through Hydrus, wetting fronts are more restricted to upper soil layers, resulting in higher evaporative losses, lower soil moisture, and bottom drainage in drylands. While at our humid site in the Ethiopian Highlands, there are minimal differences in hydrological outcomes; in drylands, the more intense and intermittent rainfall in CP4A means surface runoff is up to ten times higher and bottom drainage up to 25 times higher. We conclude that dryland hydrology is highly sensitive to climate model representation of convection and that forcing hydrological model projections with convectional climate models that parameterise the average effects of convection risks underestimating future crop health, groundwater availability, or flood risk

Understanding the potential of climate teleconnections to project future groundwater drought

Predicting the next major drought is of paramount interest to water managers globally. Estimating the onset of groundwater drought is of particular importance, as groundwater resources are often assumed to be more resilient when surface water resources begin to fail. A potential source of long-term forecasting is offered by possible periodic controls on groundwater level via teleconnections with oscillatory ocean–atmosphere systems. However, relationships between large-scale climate systems and regional to local-scale rainfall, evapotranspiration (ET) and groundwater are often complex and non-linear so that the influence of long-term climate cycles on groundwater drought remains poorly understood. Furthermore, it is currently unknown whether the absolute contribution of multi-annual climate variability to total groundwater storage is significant. This study assesses the extent to which multi-annual variability in groundwater can be used to indicate the timing of groundwater droughts in the UK. Continuous wavelet transforms show how repeating teleconnection-driven 7-year and 16–32-year cycles in the majority of groundwater sites from all the UK's major aquifers can systematically control the recurrence of groundwater drought; and we provide evidence that these periodic modes are driven by teleconnections. Wavelet reconstructions demonstrate that multi-annual periodicities of the North Atlantic Oscillation, known to drive North Atlantic meteorology, comprise up to 40 % of the total groundwater storage variability. Furthermore, the majority of UK recorded droughts in recent history coincide with a minimum phase in the 7-year NAO-driven cycles in groundwater level, providing insight into drought occurrences on a multi-annual timescale. Long-range groundwater drought forecasts via climate teleconnections present transformational opportunities to drought prediction and its management across the North Atlantic region

A conceptual model for climatic teleconnection signal control on groundwater variability in the UK and Europe

The ability to predict future variability of groundwater resources in time and space is of critical importance to drought management. Periodic control on groundwater levels from oscillatory climatic systems (such as the North Atlantic Oscillation) offers a potentially valuable source of longer term forecasting capability. While some studies have found evidence of the influence of such climatic oscillations within groundwater records, there is little information on how periodic signals propagate between a climatic system and a groundwater resource. This paper develops a conceptual model of this relationship for groundwater resources in the UK and Europe, based on a review of current research. The studies reviewed here reveal key spatial and temporal signal modulations between climatic oscillations, precipitation, groundwater recharge and groundwater discharge. Generally positive correlations are found between the NAO (as a dominant influence) and precipitation in northern Europe indicating a strong control on water available for groundwater recharge. These periodic signals in precipitation are transformed by the unsaturated and saturated zones, such that signals are damped and lagged. This modulation has been identified to varying degrees, and is dependent on the shape, storage and transmissivity of an aquifer system. This goes part way towards explaining the differences in periodic signal strength found across many groundwater systems in current research. So that an understanding of these relationships can be used by water managers in building resilience to drought, several research gaps have been identified. Among these are improved quantification of spatial groundwater sensitivity to periodic control, and better identification of the hydrogeological controls on signal lagging and damping. Principally, research needs to move towards developing improved predictive capability for the use of periodic climate oscillations as indicators of longer term groundwater variability