North Uist Research Articles

A Hebridean Plough-type

Material culture, Ethnology, Folklore, Scottish History, Rural Life, Regional Studies, Local Studies, Hebrides, National Museums Scotland, Museums, Museology, European ethnology, plough, ploughing, South Uist, North Uist, Benbecula, West Kilbride, Clearances, Highland Clearances

What Is the Relationship between Remote Rural Island Place and Perspectives on Ageing of Mid-life Women?

This article makes an original contribution to social gerontology and nissology by addressing the knowledge gap on contemporary gendered ageing in remote, rural island places. Drawing on empirical data gathered through in-depth interviews with 12 mid-life (48-69 years old) women living in the Uist islands of the Outer Hebrides in Scotland, the relationship between ageing and remote rural island place is examined. Reflecting the participant narratives, this study discusses personal and place identities, while exploring place attachment and its relationship with gendered island ageing. This qualitative work adopts a lifecourse framework in order to acknowledge lived experience and cultural context from childhood to adulthood. Data were gathered and analysed through the prism of constructivist grounded theory, a methodology well placed for exploratory research of topics about which relatively little is known. Rich participant insight and analysis eschew island mono-culturalism, instead extending the discourse around remote rural island ageing as distinct from mainland rural ageing. Empirical data informs substantive theory, and fresh considerations on gendered mid-life ageing and remote island place are offered for academia. Findings from this study indicate diverse relationships between ageing and place amongst mid-life women living in the Outer Hebridean regions of North Uist, South Uist, Benbecula and Berneray. The connection between ageing and island place is experienced through place attachment, and is influenced by a range of socio-economic factors: primarily of relevance to this study is that of the natural environment. Perspectives on ageing reflect lived lifecourse experience and thus vary between those native and non-native to the Outer Hebrides; those who live with a partner or alone; those who have children and those child-free; and between those who enjoy socio-economic stability and those who do not.

Reproductive isolation in a three-way contact zone.

Contact zones between divergent forms within a species provide insight into the role of gene flow in adaptation and speciation. Previous work has focused on contact zones involving only two divergent forms, but in nature, many more than two populations may overlap simultaneously and experience gene flow. Patterns of introgression in wild populations are, therefore, likely much more complicated than is often assumed. We begin to address this gap in current knowledge by investigating patterns of divergence and introgression across a complex natural contact zone. We use phenotypic and genomic data to confirm the existence of a three-way contact zone among divergent freshwater resident, saltwater resident and saltwater migratory three-spined stickleback (Gasterosteus aculeatus) on the island of North Uist, Scottish Western Isles. We find evidence for hybridization, mostly between saltwater resident and saltwater migratory forms. Despite hybridization, genomic analyses reveal pairwise islands of divergence between all forms that are maintained across the contact zone. Genomic cline analyses also provide evidence for selection and/or hybrid incompatibilities in divergent regions. Divergent genomic regions occur across multiple chromosomes and involve many known adaptive loci and several chromosomal inversions. We also identify distinct immune gene expression profiles between forms, but no evidence for transgressive expression in hybrids. Our results suggest that reproductive isolation is maintained in this three-way contact zone, despite some hybridization, and that reduced recombination in chromosomal inversions may play an important role in maintaining this isolation.

Development of resident and migratory three-spined stickleback, Gasterosteus aculeatus.

The three-spined stickleback (Gasterosteus aculeatus) is a teleost fish and a model organism in evolutionary ecology, useful for both laboratory and natural experiments. It is especially valued for the substantial intraspecific variation in morphology, behaviour and genetics. Classic work of Swarup (1958) has described the development in the laboratory of embryos from a single freshwater population, but this was carried out at higher temperature than many stickleback would encounter in the wild and variation between populations was not addressed. Here we describe the development of embryos from two sympatric, saltwater ecotypes of stickleback from North Uist, Scotland raised at 14°C, the approximate temperature of North Uist lochs in the breeding season. The two ecotypes were (a) a large, migratory form in which the adults are completely plated with bony armour and (b) a smaller, low-plated form that is resident year-round in saltwater lagoons. By monitoring embryos every 24-hours post fertilisation, important characteristics of development were observed and photographed to provide a reference for North Uist ecotypes at this temperature. Hatching success was greater than 85% and did not differ between resident and migratory stickleback, but migratory eggs hatched significantly earlier than the resident ecotype. Our work provides a framework that can now be used to compare stickleback populations that may also grow in distinct environmental conditions, to help understand the breadth of normal developmental features and to characterise abnormal development.

Minke whale entanglement in static fishing gear: identifying consistent areas of high risk in Western Scotland

Abstract Entanglement in static fishing gear is the largest cause of non-natural mortality for minke whales (Balaenoptera acutorostrata) in Scottish waters. To mitigate whale entanglement, one priority is to identify areas where the risk of entanglement is consistently high. Sightings data for minke whales and creel fleets were collected by the Hebridean Whale and Dolphin Trust, during vessel line transect surveys conducted between 2008 and 2014. Habitat modelling was used to relate survey, environmental, and temporal variables to the co-occurrence of minke whales and creels in coastal waters of western Scotland. This revealed that minke whale occurrence was related to depth, peaking around 70 m. Using predictive habitat modelling, the overlap between minke whale habitat and the creel fishery was measured as risk of entanglement. A method was developed to quantify the consistency of risk over the seven-year time period. This allowed for the identification of areas where there had been a consistently low, medium, or high risk of entanglement from 2008 to 2014. The three areas with a consistent high risk of entanglement were identified: Inner Sound and Sound of Raasay, east of North and South Uist, and north of The Small Isles. The method presented here could be used to guide management to areas where mitigation efforts will be the most consistently effective over time.

Ecological constraint, rather than opportunity, promotes adaptive radiation in three-spined stickleback (Gasterosteus aculeatus) on North Uist.

The context and cause of adaptive radiations have been widely described and explored but why rapid evolutionary diversification does not occur in related evolutionary lineages has yet to be understood. The standard answer is that evolutionary diversification is provoked by ecological opportunity and that some lineages do not encounter the opportunity. Three-spined sticklebacks on the Scottish island of North Uist show enormous diversification, which seems to be associated with the diversity of aquatic habitats. Sticklebacks on the neighboring island of South Uist have not been reported to show the same level of evolutionary diversity, despite levels of environmental variation that we might expect to be similar to North Uist. In this study, we compared patterns of morphological and environmental diversity on North and South Uist. Ancestral anadromous sticklebacks from both islands exhibited similar morphology including size and bony "armor." Resident sticklebacks showed significant variation in armor traits in relation to pH of water. However, North Uist sticklebacks exhibited greater diversity of morphological traits than South Uist and this was associated with greater diversity in pH of the waters of lochs on North Uist. Highly acidic and highly alkaline freshwater habitats are missing, or uncommon, on South Uist. Thus, pH appears to act as a causal factor driving the evolutionary diversification of stickleback in local adaptation in North and South Uist. This is consistent with diversification being more associated with ecological constraint than ecological opportunity.

Spatial heterogeneity in pH, body size and habitat size generates ecological opportunity in an evolutionary radiation.

Much of the biological diversity we see today is thought to be the product of evolutionary radiation, the rapid proliferation of species from a single ancestor into multiple discrete forms. Spatial heterogeneity in environmental variables has been proposed as creating the necessary ecological opportunity to stimulate evolutionary radiation. Nonetheless, the ecological mechanisms generating and maintaining diversity in spatially heterogeneous environments are not fully understood. The authors investigated the role of strong spatial heterogeneity in generating ecological opportunity in an evolutionary radiation of freshwater populations of the three-spined stickleback (Gasterosteus aculeatus L.) on the island of North Uist using a spatially explicit Bayesian model. The authors identified pH, loch surface area and body size as predictors of variance in the number of lateral plates that comprise anti-predator armour in G. aculeatus. An East-West gradient of pH, a product of the distinctive environment of North Uist, generates a robust selective environment facilitating G. aculeatus evolutionary radiation. Larger lochs were associated with atypical phenotypes, possibly related to larger population sizes and greater selection efficiency. An association between pH and lateral plate number is likely an effect of body size, with a positive relationship between body size and lateral plate number that is mediated by swimming efficiency in G. aculeatus.

New insights into the structure, geology and hydrocarbon prospectivity along the central-northern Corona Ridge, Faroe–Shetland Basin

The Faroe–Shetland Basin (FSB) is one of the only significant exploration frontiers remaining on the UK Continental Shelf. Over half of the basin's discovered reserves and resources lie along two intra-basinal highs, the Corona Ridge and the Rona Ridge. In contrast to the Rona Ridge, the central-northern Corona Ridge has received much less attention. To reveal new insights into the geology, structural configuration and hydrocarbon prospectivity of the central-northern Corona Ridge, we analyse 3D seismic data and data from the exploration wells 213/23-1 (Eriboll), 214/21a-2 (South Uist) and 213/25c-1V (North Uist). This study extends the Colsay T40–T45 sub- and intra-basaltic play concept from the Rosebank Field NE along the Corona Ridge, at least into well 213/23-1. Analysis also suggests that no Triassic strata are present within well 213/23-1, challenging the previous understanding of Triassic distribution within the central FSB. Our findings show that the central-northern Corona Ridge is structurally complex, comprising a series of discrete basement-bounding faults, downflank fault terraces and faults that are oblique to the dominant NE–SW-striking structural fabric of the FSB.

Arthur David Bethune

Arthur David Bethune was born in Edinburgh and, thanks to a bursary gained at George Watson’s College, was able to study medicine at Edinburgh University, inspired by his older sister,...

Influence of lighting environment on social preferences in sticklebacks from twodifferent photic habitats. II. Shoaling and mate preferences of lab-bred fishes.

Different environmental conditions may lead to diverse morphological, behavioral, and physiological adaptations of different populations of the same species. Lighting conditions, for example, vary vastly especially between aquatic habitats, and have been shown to elicit adaptations. The availability of short-wave ultraviolet (UV) light is especially fluctuating, as UV wavelengths are attenuated strongly depending on water properties. The island of North Uist, Scotland, comprises 2 differential habitat types, tea-stained and clear-water lakes, varying considerably in UV transmission. In previous studies, wild-caught 3-spined stickleback Gasterosteus aculeatus populations (3 populations of each habitat type) were tested with respect to their shoaling and mate preferences for fish viewed under UV-present and UV-absent conditions. The results revealed a habitat-dependent preference of UV cues during shoal choice (tea-stained populations: preference for UV-absent condition in tea-stained water; clear-water populations: no preference in clear-water) but an overall preference for UV-present conditions during mate choice. To assess genetic influences on these behavioral patterns, similar experiments were conducted with lab-bred F1-generations of the same stickleback populations that were raised in a common environment (i.e. standardized clear-water conditions). Offspring of sticklebacks from tea-stained lakes tended to prefer shoals viewed under UV-absent conditions (only in tea-stained water), while sticklebacks from clear-water lakes showed a significant preference for the shoal viewed under UV-present conditions in clear-water but not in tea-stained water. Mate-preference experiments demonstrated that females from the tea-stained lakes significantly preferred and females from the clear-water lakes preferred by trend the male viewed under UV-present conditions in the clear-water treatment. The results for both shoaling- and mate-preference tests were largely similar for wild-caught and lab-bred sticklebacks, thus hinting at a genetic basis for the preference patterns.

Earthworms in past and present agricultural landscapes of Hebridean Scotland

The Hebrides of Scotland constitute a unique set of island environments with a long history of human settlement and agriculture. Earthworm community surveys were undertaken in selected agricultural landscapes of Inner (Isle of Rum) and Outer (North and South Uist) Hebrides. On North Uist, earthworms were sampled from areas of Blackland (organic, anthropic, acidic agricultural soils) and on South Uist in machair (sandy, fertile, low-lying grassy pasture). Specific grassland and cultivated areas with various organic additions - including dung and seaweed - were targeted, using hand-sorting of soil for earthworms plus mustard vermifuge extraction. Work on Rum investigated earthworms in ridge and furrow (lazybed) agricultural systems, abandoned almost 200 years ago and since uncultivated, but grazed by ungulates. On the Uists, nine earthworm species were identified, representing all three ecological categories, but dominated by the epigeics, Dendrobaena octaedra and Lumbricus rubellus. Densities and biomasses across Blackland soils ranged from 10-130 ind. m−2 and 2.3–33.7 g m−2, respectively. Here, 5 species were present, and management had a significant effect on species richness and abundance with most earthworms present in recently restored lazybeds. In the machair soils, the corresponding measurements were 4–220 ind. m−2 and 0.8–89.0 g m−2. Significantly higher earthworm densities and biomasses were recovered below cattle dung pats compared with dung-free areas. Cultivated areas in machair were less diverse and had lower earthworm densities than uncultivated. On Rum, ridge and furrow abundances did not differ clearly with 24–102 and 34–112 ind. m−2 respectively and biomasses of 7.4–26.3 and 8.8–30.8 g m−2. Here, Aporrectodea caliginosa (49%), L. rubellus (23%) and Dendrodrilus rubidus (19%) dominated of the seven species found. Further research on earthworms in the Hebrides is warranted.

Courtship behavior, nesting microhabitat, and assortative mating in sympatric stickleback species pairs.

The maintenance of reproductive isolation in the face of gene flow is a particularly contentious topic, but differences in reproductive behavior may provide the key to explaining this phenomenon. However, we do not yet fully understand how behavior contributes to maintaining species boundaries. How important are behavioral differences during reproduction? To what extent does assortative mating maintain reproductive isolation in recently diverged populations and how important are “magic traits”? Assortative mating can arise as a by‐product of accumulated differences between divergent populations as well as an adaptive response to contact between those populations, but this is often overlooked. Here we address these questions using recently described species pairs of three‐spined stickleback (Gasterosteus aculeatus), from two separate locations and a phenotypically intermediate allopatric population on the island of North Uist, Scottish Western Isles. We identified stark differences in the preferred nesting substrate and courtship behavior of species pair males. We showed that all males selectively court females of their own ecotype and all females prefer males of the same ecotype, regardless of whether they are from species pairs or allopatric populations. We also showed that mate choice does not appear to be driven by body size differences (a potential “magic trait”). By explicitly comparing the strength of these mating preferences between species pairs and single‐ecotype locations, we were able to show that present levels of assortative mating due to direct mate choice are likely a by‐product of other adaptations between ecotypes, and not subject to obvious selection in species pairs. Our results suggest that ecological divergence in mating characteristics, particularly nesting microhabitat may be more important than direct mate choice in maintaining reproductive isolation in stickleback species pairs.

New finding of melanic three-spined sticklebacks Gasterosteus aculeatus in the Scottish Hebrides

Colour traits can be elaborated through sexual selection and have potential to drive reproductive isolation. Male three-spined sticklebacks (Gasterosteus aculeatus) express striking visual signals to attract choosy females during courtship, typically expressed as red carotenoid-based pigmentation on their throat and jaw during the breeding season, along with blue eyes and blue/green flanks. The extent and intensity of red colouration in males have been linked to fitness benefits to females, including body condition, parasite resistance, parental ability and nest defence. In some populations in the Pacific Northwest of North America, male three-spined sticklebacks express melanic nuptial colouration. In these populations, male possess black throats instead of red, and have dark or black bodies. Melanic males are associated with waterbodies that are red-shifted due to the presence of tannins, where the ambient light environment is dominated by long wavelengths. Here we report the first discovery outside North America of melanic populations of three-spined sticklebacks on the island of North Uist in the Scottish Hebrides, on the northwest Atlantic coast of Europe. These populations are associated with a hotspot of stickleback morphological diversity and occur in association with red-shifted waterbodies.

Delivering offsite modular construction in the water sector: a Scottish case study

Offsite-manufactured modular water treatment plants can improve water quality and safety as well as deliver certainty and savings in time, costs, resources, logistics and emissions. This paper describes the collaborative design and delivery of a new 1·3 Ml/d Lochmaddy water treatment works for Scottish Water on the remote island of North Uist in the Outer Hebrides. By changing the treatment method to nanofiltration and using an offsite modular approach, the project team cut costs and programme by over a third. The 12 modules for the treatment building were designed, fabricated, assembled, tested and pre-commissioned in the factory before delivery to site, where they were installed in just 4 weeks.

Admixture between Ancient Lineages, Selection, and the Formation of Sympatric Stickleback Species-Pairs.

Ecological speciation has become a popular model for the development and maintenance of reproductive isolation in closely related sympatric pairs of species or ecotypes. An implicit assumption has been that such pairs originate (possibly with gene flow) from a recent, genetically homogeneous ancestor. However, recent genomic data have revealed that currently sympatric taxa are often a result of secondary contact between ancestrally allopatric lineages. This has sparked an interest in the importance of initial hybridization upon secondary contact, with genomic reanalysis of classic examples of ecological speciation often implicating admixture in speciation. We describe a novel occurrence of unusually well-developed reproductive isolation in a model system for ecological speciation: the three-spined stickleback (Gasterosteus aculeatus), breeding sympatrically in multiple lagoons on the Scottish island of North Uist. Using morphological data, targeted genotyping, and genome-wide single-nucleotide polymorphism data, we show that lagoon resident and anadromous ecotypes are strongly reproductively isolated with an estimated hybridization rate of only ∼1%. We use palaeoecological and genetic data to test three hypotheses to explain the existence of these species-pairs. Our results suggest that recent, purely ecological speciation from a genetically homogeneous ancestor is probably not solely responsible for the evolution of species-pairs. Instead, we reveal a complex colonization history with multiple ancestral lineages contributing to the genetic composition of species-pairs, alongside strong disruptive selection. Our results imply a role for admixture upon secondary contact and are consistent with the recent suggestion that the genomic underpinning of ecological speciation often has an older, allopatric origin.

Beverley Ballin Smith (ed.), Life on the Edge: The Neolithic and Bronze Age of Iain Crawford's Udal, North Uist

Beverley Ballin Smith (ed.), <i>Life on the Edge: The Neolithic and Bronze Age of Iain Crawford's Udal, North Uist</i>

Predictable genome-wide sorting of standing genetic variation during parallel adaptation to basic versus acidic environments in stickleback fish.

Genomic studies of parallel (or convergent) evolution often compare multiple populations diverged into two ecologically different habitats to search for loci repeatedly involved in adaptation. Because the shared ancestor of these populations is generally unavailable, the source of the alleles at adaptation loci, and the direction in which their frequencies were shifted during evolution, remain elusive. To shed light on these issues, we here use multiple populations of threespine stickleback fish adapted to two different types of derived freshwater habitats—basic and acidic lakes on the island of North Uist, Outer Hebrides, Scotland—and the present‐day proxy of their marine ancestor. In a first step, we combine genome‐wide pooled sequencing and targeted individual‐level sequencing to demonstrate that ecological and phenotypic parallelism in basic‐acidic divergence is reflected by genomic parallelism in dozens of genome regions. Exploiting data from the ancestor, we next show that the acidic populations, residing in ecologically more extreme derived habitats, have adapted by accumulating alleles rare in the ancestor, whereas the basic populations have retained alleles common in the ancestor. Genomic responses to selection are thus predictable from the ecological difference of each derived habitat type from the ancestral one. This asymmetric sorting of standing genetic variation at loci important to basic‐acidic divergence has further resulted in more numerous selective sweeps in the acidic populations. Finally, our data suggest that the maintenance in marine fish of standing variation important to adaptive basic‐acidic differentiation does not require extensive hybridization between the marine and freshwater populations. Overall, our study reveals striking genome‐wide determinism in both the loci involved in parallel divergence, and in the direction in which alleles at these loci have been selected.

A Conservative Party? Pots and People in the Hebridean Neolithic

Recent analysis of the ceramic assemblage from the Neolithic loch islet settlement of Eilean Dòmhnuill, North Uist, in the Western Isles of Scotland has highlighted the intense conservatism of the potting traditions over a period of more than 800 years. Hebridean Neolithic pottery exhibits clear relationships with pottery from Argyll, Arran, and Bute, as well as Orkney and the north-east mainland of Scotland. It appears to have developed a distinctive, often decoratively elaborate regional form very soon after its initial appearance, which subsequently appears to have undergone little or no significant change until the introduction of Grooved Ware in the early 3rd millenniumbc. An association exists between large assemblages of elaborately decorated Hebridean pottery and a number of artificial islets in freshwater lochs, some very small and producing little or no evidence for domestic activities. This might be explained by the importance of commensality in mediating relations between small communities in the Western Isle at such sites following the introduction of agriculture in the 2nd quarter of the 4th millenniumbc. The conservatism and stasis evident at Eilean Dòmhnuill, in the face of environmental decline, raises wider issues around the adaptive capabilities of the first farming communities prior to significant social changes in the earlier 3rd millenniumbc.

Beyond the meta-ecosystem? The need for a multi-faceted approach to climate change planning on coastal wetlands: An example from South Uist, Scotland

Exposed, low-lying dune-wetland habitat complexes may have multi-faceted functionality that means they are effectively meta-ecosystems, where inter-acting nearshore, littoral, dune and freshwater components and processes must be considered together, sometimes in conjunction with interactions with contiguous inland habitats. The low-lying dune-machair-marsh-loch (lake) ecosystems of South Uist, Benbecula and North Uist in the Outer Hebrides of Scotland exhibit such functionality, and investigation of a former loch basin at the south end of South Uist has revealed an unexpected level of complexity that also identifies a particularly high exposure to climate change in the coastal hinterland, particularly in terms of water relationships, though the possibility of significant change to the coastal frontage must also be considered in contingency planning. This investigation is described by sector, then drawn together in the context of climate change. It is suggested that the environmental setting of the Uists conforms to the concept of the meta-ecosystem in spatial terms, but with additional legacy and socio-economic components, so that there is effectively a socio-spatio-temporal meta-ecosystem. It is vital that this complexity is understood and accommodated in all flood contingency and adaptation planning, and the paper attempts to assist this by presenting an overview of the functional role and context of water in the coastal lowlands of the Uists.

Otolith development in wild populations of stickleback: Jones & Hynes method does not apply to most populations.

This paper critiques Jones & Hynes (1950) findings by analysing sequential samples of otoliths from three wild populations of Gasterosteus aculeatus from North Uist, Scotland and Nottingham, England. Contrary to Jones & Hynes (1950), but coincident with the finding of later researchers, our results showed that no true translucent ring formed in the otolith of G. aculeatus during their first summer. The first translucent ring was probably starting to be formed by the end of summer and was completed by the end of their first winter. There was no second opaque ring in the otoliths of G. aculeatus before they passed their first winter. The second opaque ring was just starting to appear by early April of the second year in the southern population i.e. Nottingham, but later, by May, in the northern populations i.e. North Uist. Formation of the opaque ring in G. aculeatus mostly occurs in spring and summer, with younger fish starting earlier. In contrast, the formation of translucent rings is mostly during autumn and winter, but can be more widespread through the year, possibly as a result of reproductive investment.