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How individual animals respond to climate change is key to whether populations will persist or go extinct. Yet, few studies investigate how changes in individual behavior underpin these population-level phenomena. Shifts in the distributions of migratory animals can occur through adaptation in migratory behaviors, but there is little understanding of how selection and plasticity contribute to population range shift. Here, we use long-term geolocator tracking of Balearic shearwaters (Puffinus mauretanicus) to investigate how year-to-year changes in individual birds’ migrations underpin a range shift in the post-breeding migration. We demonstrate a northward shift in the post-breeding range and show that this is brought about by individual plasticity in migratory destination, with individuals migrating further north in response to changes in sea-surface temperature. Furthermore, we find that when individuals migrate further, they return faster, perhaps minimizing delays in return to the breeding area. Birds apparently judge the increased distance that they will need to migrate via memory of the migration route, suggesting that spatial cognitive mechanisms may contribute to this plasticity and the resulting range shift. Our study exemplifies the role that individual behavior plays in populations’ responses to environmental change and highlights some of the behavioral mechanisms that might be key to understanding and predicting species persistence in response to climate change.

The invertebrate fauna of the Ogof Draenen cave system in South Wales was investigated between 2012 and 2015. Fifty-nine sites were sampled within the cave, comprising 51 sites on vadose streams, four pools and four dripping avens. The main method employed in vadose streams was three minutes of “kick sampling” using an FBA pattern net. Pools and smaller flows of water were sampled using a combination of netting and manual searching. Sampling was also carried out on the surface at six resurgences and four surface seepages/streams feeding into dolines (stream sinks) that are known from dye-tracing to be connected to the cave system below. Sixty-two invertebrate taxa were recorded in the cave system, 43 from the sinks, and 58 from the resurgences. Most cave samples were dominated by Oligochaeta and stygobiontic Crustacea including the amphipods Niphargus fontanus Bate 1859 and Microniphargus leruthi Schellenberg 1934, the isopod Proasellus cavaticus Leydig 1871 sensu Henry 1970 and the syncarid Antrobathynella stammeri Jakobi 1954. The records of M. leruthi, a species only discovered in Britain in 2010, are the first from a Welsh cave system; and the records of A. stammeri are the first for this species from Wales. Four eustygophilic species were also recorded in the cave, which were not present in samples collected from the resurgences or sinks and may therefore represent isolated subterranean populations. These included: the oligochaete worm Dorydrilus michaelseni Piguet 1913, the ostracod Cavernocypris subterranea (Wolf 1920), the copepod Paracyclops fimbriatus (Fischer 1853) and the halacarid mite Soldanellonyx chappuisi (Walter 1917). The amphipod Gammarus pulex (Linnaeus 1758) occurred in the sinks, resurgences and at several sites within the cave, some at a considerable distance underground, and amongst large populations of stygobiontic Crustacea. These showed varying degrees of depigmentation and were highly likely to represent a eustygophilic population. Stygo

The Upper Cretaceous Chalk of southern England is the UK’s most important aquifer, providing more than 75% of the public supply for southeast England, including London. The aquifer also sustains rivers and wetlands, and their associated groundwater dependent ecosystems. However, the aquifer is facing a multitude of threats including over-abstraction, nitrate pollution, and climate change. The Chalk is a complex aquifer in which groundwater flow is through the matrix, fractures and karstic dissolutional voids. The Chalk matrix has a porosity of around 35% (Bloomfield et al., 1995). The matrix is thought to provide an important contribution to storage, although the size of the pore throats is very small, and therefore the permeability is very low (Price et al., 1993). The average permeability of 977 core samples was only 6.3 x 10-4 m/day (Allen et al., 1997). The matrix is particularly important in solute transport, because solutes move between the matrix and the more permeable parts of the aquifer via diffusion (Foster 1975). The unmodified fracture network provides an important contribution to storage and flow, and has a hydraulic conductivity of about 0.1 m/d, and a transmissivity of about 20 m2/day (Price, 1987). However, it is the dissolutionally enlarged fissures and conduits that make the Chalk such a good aquifer. The median transmissivity from 2100 pumping tests is 540 m2/day, and the 25th and 75th percentiles are 190 and 1500 m2/day respectively (MacDonald and Allen, 2001). Borehole packer testing, logging and imaging have shown that most of this transmissivity comes from a small number of dissolutional voids (e.g. Tate et al., 1970; Schurch and Buckley, 2002). Laterally extensive lithostratigraphical horizons including marl seams, bedding planes, sheet and tabular flint bands, and hard-grounds have an important influence on these groundwater flows. They are all horizons where downward percolation of water may be impeded. Dissolution often occurs where flow

The Balearic Shearwater Puffinus mauretanicus is a Critically Endangered species endemic to the Balearic Islands, subject to a severe decline that could lead to the extinction of the species within three generations (Oro et al. 2004). Predation by introduced mammals is considered the main threat facing the species at its breeding grounds, and therefore conservation action is required along with subsequent monitoring in a species where such information is lacking. In order to assess the long-term impact of a rodent eradication project on the breeding success of the species on Sa Dragonera island, a series of study plots were established in April 2013. A survey was carried out to establish the minimum number of known Apparently Occupied Sites (AOS) within each plot. All potential nest sites within each plot were sampled for the presence of a bird(s) using a combination of methods: (i) tape playback, (ii) physical sighting (by eye or with an endoscope) and (iii) obvious signs of occupation. 33 AOS in 12 study plots were identified. This project was not a whole island estimate; rather it led to the establishment of a series of repeatable study plots, providing reference estimates of breeding pairs in defined areas on the island to enable monitoring of future changes in the population size following predator removal.

Groundwater ecosystems remain poorly understood yet may provide vital ecosystem services, contain useful bio-indicators of water quality, and make a unique contribution to biodiversity. The limited understanding of these ecosystems is a result of the inaccessibility of the subsurface habitat. Boreholes provide the main sampling window into deeper non-karstic aquifers and are commonly used to investigate bacterial and invertebrate communities. We investigated the differences between borehole and aquifer hydrochemistry, bacteria, and invertebrates at different depths beneath the surface. Packers were deployed to isolate three potential aquifer habitats (fractures/conduits) intercepted by two Chalk boreholes. Hydrochemical, microbiology and invertebrates samples were then taken progressively with pumping to assess differences between borehole and aquifer communities. Invertebrate net samples were also taken from the boreholes. Invertebrates and bacteria were more abundant in the boreholes than in the aquifer, with associated water chemistry variations indicating that boreholes act as sites of enhanced biogeochemical cycling. Moreover, there was also evidence that the bacterial community structure differed between the borehole and the aquifer. Therefore this study demonstrates the challenges of assessing bacterial and invertebrate abundance within aquifers by using boreholes, which has implications for assessing the significance of their ecosystem services provision.

In Africa, groundwater is the major source of drinking water and its use for irrigation is forecast to increase substantially to combat growing food insecurity. Population growth will put additional pressures on the resource making it increasingly important to understand and characterise the resilience of groundwater to climate change. Here we present the results of a major project to characterise and map groundwater resilience in Africa. We offer some definitions of groundwater resilience drawing on the more established use of the term resilience in ecology and substantiated with focussed field studies. Groundwater resilience to long term (decadal) shifts in climate is governed by the available groundwater storage; resilience to shorter term (inter annual) climate shocks is also dominated by storage but is also influenced by the long term average (decadal) recharge to the groundwater system which will help the system recover more quickly. For many people the more pressing issue is the resilience of the water services dependant on groundwater rather than the actual groundwater resource itself. The research highlights the increased sustainability of improved water supplies targeted to the most productive parts of the aquifer. Therefore, for estimating the resilience of water sources to changes in climate, the aquifer permeability should be considered alongside storage and long term recharge.

Using combined miniature archival light and salt-water immersion loggers, we characterise the year-round individual at-sea movements of Europe’s only critically endangered seabird, the Balearic shearwater Puffinus mauretanicus, for the first time. Focusing on the non-breeding period, we show that all of the 26 breeding birds tracked from their breeding site on Mallorca in the Mediterranean Sea successfully made a 2–4 month migration into the Atlantic Ocean, where they utilised well-defined core areas off Portuguese and French coasts. As well as identifying high-risk areas in the Atlantic, our results confirm that breeding birds spend most of the year concentrated around productive waters of the Iberian shelf in the western Mediterranean. Migration phenology appeared largely unrelated to the subsequent (distinctly synchronous) breeding attempt, suggesting that any carry-over effects were compensated for during a long pre-laying period spent over winter in the Mediterranean. Using the light and salt-water immersion data alone we were also able to characterise the pattern of pre-laying visits to the colony in considerable detail, demonstrating that breeding pairs appear to coordinate their over-day visits using a high frequency of night-time visits throughout the winter. Our study shows that geolocation technology is a valuable tool for assessing the spatial distribution of risks to this critically endangered species, and also provides a low-impact method for remotely observing the detailed behaviour of seabird species that may be sensitive to disturbance from traditional study methods.

A current understanding of the hydrology of Ogof Draenen, Wales, one of the longest and most complex cave systems in Europe, is presented. Previous tracer tests are reviewed and results of two new tracer tests presented. Numerous dolines occur on the Carboniferous Millstone Grit and Limestone that outcrop around the edges of the mountains overlying Ogof Draenen, with hydrologically active sinking streams common along the boundary of these strata. Surface pollution of a doline caused diesel pollution in the cave beneath demonstrating the vulnerability of groundwater. In addition to a few recently formed hydrologically active cave passages, groundwater flow is influenced by many kilometres of fossil passages, formed during multiple phases of speleogenesis, creating vertical and horizontal misfit streams which cross or flow through large fossil passages. In the southeast of the cave, tracer testing revealed an underground watershed demonstrating the complexity of groundwater flowpaths. In the north a cave stream flows to springs which drain north to the Clydach Gorge. Small amounts of drainage in the cave may also reach springs in the Tumble Valley to the northeast, although these springs may be unconnected to the cave and fed entirely by stream sinks on the Blorenge mountainside. Multi-tracer injections within the cave revealed that it’s major underground streams flow south to feed large springs at Snatchwood and Pontnewynyd in the Afon Lwyd valley, in a different topographical catchment some 8 km beyond the known cave, with rapid groundwater velocities of up to 4km/day. Nine other springs in the Afon Lwyd valley appear unconnected to the Ogof Draenen streams, being fed independently by sinking streams on the local mountainside. In addition, we show that specific electrical conductance varies greatly both between and within springs, is negatively related to background fluorescence, and can be used to aid interpretation of dye tracer data.

Understanding the permeability of Quaternary deposits is important for assessing their role in groundwater flooding, determining how they support wetlands, and evaluating the sustainable resource potential. However characterising their permeability can be difficult because of the extreme lateral and vertical variability in the nature of the deposits. BGS have been involved in several studies in Morayshire, Scotland, where measuring the permeability of glaciofluvial Quaternary deposits was critical to designing effective flood alleviation schemes. Initial site investigation methods carried out by contractors involving falling head tests, particle size distribution analysis, and geological logs were not compatible with the results from constant rate pumping tests. A comprehensive hydrogeological investigation coupled with groundwater modelling of the Quaternary deposits of the area has enabled the general permeability structure of the Quaternary deposits to be understood. There is a general decrease in the permeability of the Quaternary deposits with depth below the surface occurring over a large part of the study area . Results also suggest that sedimentation and the degree of compaction may be more important than the particle size distribution in determining permeability of the Quaternary deposits, and therefore lab derived permeability values are less reliable than field measurements. The techniques most powerful in unravelling the permeability structure of the Quaternary Deposits were: short constant rate pumping tests; geological reconstruction of the deposition of the sediments; Guelph permeameter measurements of known deposits at outcrop, salt dilution tests in boreholes; and a survey of groundwater chemistry and residence times.