First genetic evidence that invasive bullhead (Cottus L. 1758) in Scotland is of English origin and the difficulty of resolving the European Cottus species taxonomy

The European bullhead (Cottus gobio) is widely distributed across Europe, and within the UK is native to England and Wales, where it is protected under the Habitats Directive. In Scotland, however, the species is considered invasive and thriving populations are recorded in the Forth and Clyde river catchments, and the Ale Water in the Scottish Borders. The genetic identity of the Scottish populations has not been established. There is also debate about the status of the European bullhead and its validity as single species, a species complex with several unresolved species, or distinct different species in its European distribution range. There is therefore a need to determine the taxonomy and likely source of the novel Scottish populations. Genetic analyses using cytochrome oxidase 1 (COI) mitochondrial DNA sequences were undertaken on specimens from the Forth and Clyde catchments, and combined with the results of morphological characteristics to provide a comprehensive assessment of the taxonomic classification for Scottish bullheads. There was considerable variation in morphological characteristics between populations within Scotland and a wider range of variability than previously recorded for English populations. Genetically the Scottish populations were very closely related to English specimens, supporting the hypothesis of introduction directly from England to Scotland. In terms of broader relationships, Scottish specimens are genetically more closely related to the ostensible species Chabot fluviatile Cottus perifretum, which has been suggested as one of a complex of species across Europe. Morphologically they exhibit characteristics on the spectrum between C. perifretum and C. gobio. There is an urgent need for the clarification of the taxonomy of Cottus sp(p). to avoid confusion in future publications, legislation and management practices relating to bullheads throughout the UK and Europe.     

Investigating connectivity and seasonal differences in wind assistance in the migration of Common Sandpipers

Many migratory bird species have undergone recent population declines, but there is considerable variation in trends between species and between populations employing different migratory routes. Understanding species-specific migratory behaviours is therefore of critical importance for their conservation. The Common Sandpiper Actitis hypoleucos is an Afro-Palaearctic migratory bird species whose European populations are in decline. We fitted geolocators to individuals breeding in England or wintering in Senegal to determine their migration routes and breeding or non-breeding locations. We used these geolocator data in combination with previously published data from Scottish breeding birds to determine the distributions and migratory connectivity of breeding (English and Scottish) and wintering (Senegalese) populations of the Common Sandpiper, and used simulated random migrations to investigate wind assistance during autumn and spring migration. We revealed that the Common Sandpipers tagged in England spent the winter in West Africa, and that at least some birds wintering in Senegal bred in Scandinavia; this provides insights into the links between European breeding populations and their wintering grounds. Furthermore, birds tagged in England, Scotland and Senegal overlapped considerably in their migration routes and wintering locations, meaning that local breeding populations could be buffered against habitat change, but susceptible to large-scale environmental changes. These findings also suggest that contrasting population trends in England and Scotland are unlikely to be the result of population-specific migration routes and wintering regions. Finally, we found that birds used wind to facilitate their migration in autumn, but less so in spring, when the wind costs associated with their migrations were higher than expected at random. This was despite the wind costs of simulated migrations being significantly lower in spring than in autumn. Indeed, theory suggests that individuals are under greater time pressures in spring than in autumn because of the time constraints associated with reproduction.     

The census and selective service

Abstract

A number of studies are reviewed to show that the mean level of measured intelligence in Scotland is approximately three to four IQ points lower than that in England. These results are a striking contrast with another set of findings showing that in the nineteenth century Scotland had a greater proportional output of people of intellectual distinction than did England. Evidence on Scottish‐English differences in education, parental attention, and per capita income suggests that none of these factors can explain the difference in mean IQ. It is suggested that the principal cause of the reduced mean intelligence in Scotland lies in the selective emigration of the more intelligent, and evidence is reviewed to show that this emigration has occurred for at least a century.     

Genetic variation in native and introduced populations of the 'New Zealand flatworm', Arthurdendyus triangulatus

The internal transcribed spacer regions (ITS1 and ITS2) including the 5.8S region of the ‘New Zealand flatworm’, Arthurdendyus triangulates, are 1004 base pairs in length. Restriction fragment length polymorphism analysis of PCR products (PCR‐RFLP) was conducted on A. triangulates specimens from 45 locations in Northern Ireland, Scotland, England and New Zealand. Seven restriction endonucleases (Alu I, Rsa I, Sau3A I, Cfo I, Nde I, Dde I, and Mbo I) were used to reveal intraspecific variation. Analysis of molecular variance revealed the presence of population genetic substructuring, with most genetic heterogeneity present between populations rather than between individuals or geographical regions. No distinct differences were found between Northern Irish and Scottish populations but phylogenetic analysis supports the hypothesis of multiple introductions from New Zealand. There was no significant relationship between genetic distance and geographic distance, as would be expected for natural spread, indicating that this species is largely anthropochorous, even in parts of New Zealand.     

Wear Fast,Die Young: More Worn Teeth and Shorter Lives in Iberian Compared to Scottish Red Deer

Teeth in Cervidae are permanent structures that are not replaceable or repairable; consequently their rate of wear, due to the grinding effect of food and dental attrition, affects their duration and can determine an animal''s lifespan. Tooth wear is also a useful indicator of accumulative life energy investment in intake and mastication and their interactions with diet. Little is known regarding how natural and sexual selection operate on dental structures within a species in contrasting environments and how these relate to life history traits to explain differences in population rates of tooth wear and longevity. We hypothesised that populations under harsh environmental conditions should be selected for more hypsodont teeth while sexual selection may maintain similar sex differences within different populations. We investigated the patterns of tooth wear in males and females of Iberian red deer (Cervus elaphus hispanicus) in Southern Spain and Scottish red deer (C. e. scoticus) across Scotland, that occur in very different environments, using 10343 samples from legal hunting activities. We found higher rates of both incisor and molar wear in the Spanish compared to Scottish populations. However, Scottish red deer had larger incisors at emergence than Iberian red deer, whilst molars emerged at a similar size in both populations and sexes. Iberian and Scottish males had earlier tooth depletion than females, in support of a similar sexual selection process in both populations. However, whilst average lifespan for Iberian males was 4 years shorter than that for Iberian females and Scottish males, Scottish males only showed a reduction of 1 year in average lifespan with respect to Scottish females. More worn molars were associated with larger mandibles in both populations, suggesting that higher intake and/or greater investment in food comminution may have favoured increased body growth, before later loss of tooth efficiency due to severe wear. These results illustrate how independent selection in both subspecies, that diverged 11,700 years BP, has resulted in the evolution of different longevity, although sexual selection has maintained a similar pattern of relative sex differences in tooth depletion. This study opens interesting questions on optimal allocation in life history trade-offs and the independent evolution of allopatric populations.     

Mitochondrial DNA evidence of an early Holocene population expansion of threespine sticklebacks from Scotland

In this study, we analyzed the cytochrome b gene in threespine stickleback (Gasterosteus aculeatus) populations from Scotland. We found evidence of a postglacial population expansion in Scotland and large differences in genetic diversity estimates among populations. Higher levels of genetic diversity are negatively correlated with distance from the ocean. In addition, distance from the ocean and predation risk both explain variation in plate count in Scottish populations. Overall, the mtDNA data support the racemic model of evolution in threespine stickleback.     

Spatially restricted gene flow and reduced microsatellite polymorphism in the Eurasian otter Lutra lutra in Britain

Although gene flow and population fragmentationwill often have opposed effects on geneticstructure, their actual effects on many elusiveanimal species are unknown. We assessed sucheffects in British populations of the Eurasianotter Lutra lutra by analysis ofgenotypes consisting of 12 microsatellites from618 carcasses representing the period 1982–1998. Spatial patterns of genetic subdivisionand levels of polymorphism in the continuouspopulation in Scotland were estimated. Theseresults were used to infer patterns of geneflow in Scottish otters and assess theinfluence of fragmentation on the geneticstructure of otters in Wales and SW England.The latter showed no higher genetic divergencethan expected given the degree of isolation bydistance found in the Scottish population, andtheir distributions of microsatellite allelesizes provided no evidence for populationbottlenecks. Nonetheless, otters in southernBritain contained significantly lower levels ofmicrosatellite polymorphism than otters inScotland, and the population in the westernpeninsula of SW England was geneticallydistinct. These results suggested that thegenetic structure of the Scottish population isdue more to restricted contemporary gene flowthan to historical fluctuations insubpopulation size, and that the geneticstructure of the southern British populationsis due more to small historical effective sizesthan to recent declines. If spatiallyrestricted gene flow is typical of all Eurasianotter populations then data on dispersal shouldbe taken into account when sitting protectedareas for this species.     

Postglacial colonization of Ireland by mustelids, with particular reference to the badger (Meles meles L.)

There exists some confusion as to the means by which Ireland developed its current mammalian fauna. In this paper, I use a multivariate analysis of cranial measurements to test the hypothesis that Irish mustelids should resemble their Scottish counterparts more so than those from England, thus providing morphological evidence for postglacial colonization via an Ireland/Scotland landbridge. An examination of badger ( Meles meles L.), stoat ( Mustela erminea L.) and otter ( Lutra lutra L.) failed to provide support for this hypothesis. Based on these results and consideration of our knowledge of the ecology of these species, it is concluded that postglacial colonization via a landbridge was unlikely. Evidence for human-aided colonization is reviewed. It is concluded that, while further morphologic and genetic studies are very much required, the problem of postglacial colonization can only be solved through archaeozoological research.     

Diet and fish stock availability as possible factors in the mass death of auks in the North Sea

In February 1983 more than 30 000 birds died on the North Sea coasts of England and Scotland. The birds were unoiled, and there was no immediately obvious cause of death. Stomach contents of auks killed in this incident were examined to ascertain whether they provided any indication of the causal factors. Analysis of food remains showed differences between sample sites and between guillemots, Una aalge (Pont.), and razorbills, Alca tarda L. In all areas gadoid remains comprised a higher, and sandeels a lesser, proportion of the stomach contents in guillemots than in razorbills. The relative importance of clupeid remains varied with area. These differences, combined with current trends in the fisheries biology of major prey species, provided an ecological basis for a hypothesis explaining the incident. It was concluded that starvation was probably a major factor in the death of the auks, and that this may have been related to a combination of adverse weather conditions and changing patterns of abundance in North Sea sprat, Sprattus sprattus (L.), populations.     

The status of the freshwater pearl mussel <Emphasis Type="Italic">Margaritifera margaritifera</Emphasis> in Scotland: extent of change since 1990s,threats and management implications

All known rivers in Scotland with recent records of freshwater pearl mussels Margaritifera margaritifera were surveyed in 2013–2015 using a standard methodology. Freshwater pearl mussel populations were classed as: (i) apparently extinct in 11 rivers, (ii) not successfully recruiting in 44 rivers, and (iii) evidence of recent successful recruitment in 71 rivers. On a regional basis, a high proportion of extant populations were located in North and West Scotland. In all regions extant populations were characterised by low pearl mussel densities, with 97 of 115 extant Scottish populations defined as ‘rare’ (0.1–0.9 mussels per 1 m ²) or ‘scarce’ (1.0–9.9 mussels per 1 m ²). Only 18 Scottish rivers now hold pearl mussel populations in densities that are considered to be ‘common’ (10–19.9 mussels per 1 m ²) or ‘abundant’ (>20 mussels per 1 m ²). Based on survey evidence, the number of apparently extinct pearl mussel populations in Scottish rivers is now 73. The decline is particularly pronounced in the West Highlands and Western Isles strongholds. The key threats are: (i) pearl fishing, (ii) low host fish densities, (iii) pollution/water quality, (iv) climate change and habitat loss, (v) hydrological management/river engineering and (vi) ‘other factors’, such as non-native invasive species. Over the last 100 years this endangered species has been lost from much of its former Holarctic range. Scotland’s extant M. margaritifera populations continue to be of international importance, but their continued decline since the first national survey in 1998 is of great concern.     

Genetic variation of isolated and peripheral populations of Pinus sylvestris (L.) from glacial refugia

Analysis of variation at 10 polymorphic isoenzyme loci in 51 European populations of Pinus sylvestris both from its main continuous range and from isolated, marginal populations out of the continuous range, revealed differences in genetic structure. The highest genetic richness, measured as mean number of alleles per locus, was recorded for populations from the Iberian Peninsula, followed by those from Scotland and the Balkans. Marginal, isolated populations were characterized by much greater interpopulation variation than populations from the continuous range of the species. The highest mean observed heterozygosity was recorded for the Iberian populations. The highest gene flow was observed among populations in the continuous range of the species. The populations could be classified into five groups based on genetic similarities. Populations from the continuous range formed one group, those from Spain two groups, pines from Scotland one group and those from the Balkans one group. One population from Scotland was found to be most distinct from the other Scottish pines and was found to be grouped with the Balkan populations. The occurrence and frequencies of rare alleles in the populations showed a characteristic pattern, suggesting that populations from the Iberian Peninsula probably did not participate in the colonization of Europe by Pinus sylvestris after the last glaciation. In contrast, the migration of populations from the Balkan refugium into Central and Western Europe had a significant effect on the contemporary gene pools of populations of Pinus sylvestris in its continuous range.     

An East–West distribution of divergent mitochondrial haplotypes in British populations of the land snail, Cepaea nemoralis (Pulmonata)

Some continental European populations of the land snail Cepaea nemoralis have mitochondrial haplotypes that differ by up to 20% at the 16S rRNA locus. I mapped the distribution of different lineages in populations from 36 different sites in Britain and Ireland. In 93% of individuals, one of two mitochondrial lineages was found, A or. N , which differ from each other by about 6% using a 16S rRNA fragment {approximately 300 base pairs). The distribution of these two types is very striking–one is confined to Wales, West and central England, and Scotland, while the other is found mainly in East and central England. The two types meet in a transition zone. The most likely explanation for the distribution is that it reflects two routes of colonization after the last ice age. Cepaea dispersal is leptokurtic, and only limited gene flow occurs between established populations, so that the original pattern could have been retained since the post-glacial colonization. However, many environmental gradients are orientated East-West, so alternative selective explanations are possible. A distinct mitochondrial lineage, as well as fossil evidence, suggests that Ireland was colonized separately from Britain. The implications of these distributions for the origins of the puzzling geographical patterns of shell types known as 'area effects' is discussed.     

High genetic diversity at the extreme range edge: nucleotide variation at nuclear loci in Scots pine (Pinus sylvestris L.) in Scotland

Nucleotide polymorphism at 12 nuclear loci was studied in Scots pine populations across an environmental gradient in Scotland, to evaluate the impacts of demographic history and selection on genetic diversity. At eight loci, diversity patterns were compared between Scottish and continental European populations. At these loci, a similar level of diversity (θ_sil=∼0.01) was found in Scottish vs mainland European populations, contrary to expectations for recent colonization, however, less rapid decay of linkage disequilibrium was observed in the former (ρ=0.0086±0.0009, ρ=0.0245±0.0022, respectively). Scottish populations also showed a deficit of rare nucleotide variants (multi-locus Tajima''s D=0.316 vs D=−0.379) and differed significantly from mainland populations in allelic frequency and/or haplotype structure at several loci. Within Scotland, western populations showed slightly reduced nucleotide diversity (π_tot=0.0068) compared with those from the south and east (0.0079 and 0.0083, respectively) and about three times higher recombination to diversity ratio (ρ/θ=0.71 vs 0.15 and 0.18, respectively). By comparison with results from coalescent simulations, the observed allelic frequency spectrum in the western populations was compatible with a relatively recent bottleneck (0.00175 × 4N_e generations) that reduced the population to about 2% of the present size. However, heterogeneity in the allelic frequency distribution among geographical regions in Scotland suggests that subsequent admixture of populations with different demographic histories may also have played a role.     

The evolution and age of populations of Scaphinotus petersi Roeschke on Arizona Sky Islands (Coleoptera, Carabidae, Cychrini)

Populations of the ground beetle Scaphinotus petersi are isolated in subalpine conifer forest habitats on mountain ranges or Sky Islands in southeastern Arizona. Previous work on this species has suggested these populations have been isolated since the last post-glacial maximum times as warming caused this cool adapted species to retreat to high elevations. To test this hypothesis, we inferred the phylogeny from mitochondrial DNA sequence data from several Arizona Sky Island populations of Scaphinotus petersi and estimated the divergence time of the currently isolated populations. We found two major clades of Scaphinotus petersi, an eastern clade and a western group. Our results indicated most mountain ranges form clades except the Huachucas, which are polyphyletic and the Santa Catalinas, which are paraphyletic. We estimated the Pinaleño population is much older than the last glacial maximum, but the Huachuca and Pinal populations may have been fragmented from the Santa Catalina population since the post-glacial maximum times.     

Unstable dynamics and population limitation in mountain hares

The regular large-scale population fluctuations that characterize many species of northern vertebrates have fascinated ecologists since the time of Charles Elton. There is still, however, no clear consensus on what drives these fluctuations. Throughout their circumpolar distribution, mountain hares Lepus timidus show regular and at times dramatic changes in density. There are distinct differences in the nature, amplitude and periodicity of these fluctuations between regions and the reasons for these population fluctuations and the geographic differences remain largely unknown. In this review we synthesize knowledge on the factors that limit or regulate mountain hare populations across their range in an attempt to identify the drivers of unstable dynamics. Current knowledge of mountain hare population dynamics indicates that trophic interactions--either predator-prey or host-parasite--appear to be the major factor limiting populations and these interactions may contribute to the observed unstable dynamics. There is correlative and experimental evidence that some mountain hare populations in Fennoscandia are limited by predation and that predation may link hare and grouse cycles to microtine cycles. Predation is unlikely to be important in mountain hare populations in Scotland as most hares occur on sporting estates where predators are controlled, but this hypothesis remains to be experimentally tested. There is, however, emerging experimental evidence that some Scottish mountain hare populations are limited by parasites and that host-parasite interactions contribute to unstable dynamics. By contrast, there is little evidence from Fennoscandia that parasitism is of any importance to mountain hare population dynamics, although disease may cause periodic declines. Although severe weather and food limitation may interact to cause periodic high winter mortality there is little evidence that food availability limits mountain hare populations. There is a paucity of information concerning the factors limiting or regulating mountain hare populations in the Alps of Central Europe or in the tundra and taiga belts of Russia. Future research on mountain hare population dynamics should focus on the interactions between predation, parasitism and nutrition with stochastic factors such as climate and anthropogenic management including harvesting.     

Electrophoretic studies on populations of Myzjus persicae in Scotland from March to July, 1976

Specimens of Myzus persicae have been collected from field populations in Scotland and scored electrophoretically for their phenotypes at three polymorphic loci. These phenotypes were almost invariably present in individuals in one of a small number of favoured combinations, suggesting that these populations may be oligogeneous, that is, composed of large numbers of copies of a few favoured combinations of alleles. Temporal and spatial sampling at sites in East and West Scotland in 1976 has shown that different allele combination types were present in the two areas. Populations in E. Scotland contained very few specimens belonging to the organophosphorus (OP) resistant clone types (using esterase activity to infer resistance); instead there were large numbers of an OP susceptible type which has not been detected in England, but which came to predominate on cabbage and potato host plants at every site sampled during the period of rapid population increase. In contrast, populations in W. Scotland were characterised by substantial numbers of specimens belonging to OP resistant clone types and by an almost complete absence of this susceptible type. Two other distinguishable OP susceptible types were found to be common to both areas. The W. Scotland populations closely resemble N. England populations while those in E. Scotland appear to be unique to that area. Specimens of OP resistant types were only detected in E. Scotland after the beginning of June and in such relative proportions as to strongly suggest that they were migrants from W. Scotland or N. England.     

The copepod Salmincola edwardsii as a parasite of Salvelinus alpinus in Britain, and a consideration of the so-called relict fauna of Ennerdale Water

The lernaeopodid copepod Salmincola edwardsii is recorded for the first time in the British Isles as a parasite of the salmonid fish Salvelinus alpinus . Material from Ennerdale Water in the English Lake District is described and illustrated and evidence of the occurrence of the same species in four Scottish lochs is presented. An interesting biological feature of the Ennerdale population is that egg size varies almost three-fold in terms of volume in different individuals. Ennerdale's fauna is unique among those of British lakes in that it includes two crustaceans, Mysis relicta (known also from Ireland) and Limnocalanus macrurus (known nowhere else in the British Isles), both of which have been claimed as "ice-age" or "marine-glacial relicts". No satisfactory explanation of how Ennerdale could have acquired these animals has hitherto been put forward. A hypothesis which attempts to do so and which also accounts for the presence of Salmincola on the char of Ennerdale and of certain Scottish lochs, but not on populations of this fish in other Lake District lakes, is put forward. This utilizes knowledge of the biology of the animals in question, such information as is available concerning the disposition of the ice in the area at the time of its retreat, and the record of the post-glacial history of the Cumbrian lakes as preserved in their sediments.     

The diversity of earthworms in 200 Scottish fields and the possible effect of New Zealand land flatworms (Arthurdendyus triangulatus) on earthworm populations

Earthworm populations from 200 fields (132 pasture and 68 arable) in Scotland are compared. Earthworms populations from two pasture fields at a Scottish farm infested with the New Zealand terrestrial planarian, Arthurdendyus triangulates (a predator of earthworms), are compared with a subset of these 200 fields (none of which had planarians at the time of the survey). A variety of univariate and multivariate methods are used for comparison. Results from the 200 fields show that the number of individuals, number of species, richness and diversity decline eastwards and northwards across Scotland. There is an overall difference between pasture and arable fields at the same farm, with fewer anecic earthworms (Aporrectodea longa and Lumbricus terrestris), but more Aporrectodea rosea, in arable fields. Conversely, species richness and cumulative species diversity is greater in arable fields, and sample similarity is less. The planarian‐infested fields show differences from the subset of western Scottish pasture fields and from each other. Both have fewer Aporrectodea caliginosa (and endogeic total) and A. longa (and anecic total) than the western pasture fields. One field has fewer L. terrestris and fewer earthworms in total. Univariate factors show no significant differences between the infested fields and similar non‐infested fields, but multivariate analysis suggests differences. Waterlogging and recent growth of rushes in the infested fields are discussed in relation to the reduced population of earthworms and to rainfall.     

Costs and Benefits of Chemical Defence in the Red Alga Bonnemaisonia hamifera

A number of studies have shown that the production of chemical defences is costly in terrestrial vascular plants. However, these studies do not necessarily reflect the costs of defence production in macroalgae, due to structural and functional differences between vascular plants and macroalgae. Using a specific culturing technique, we experimentally manipulated the defence production in the red alga Bonnemaisonia hamifera to examine if the defence is costly in terms of growth. Furthermore, we tested if the defence provides fitness benefits by reducing harmful bacterial colonisation of the alga. Costly defences should provide benefits to the producer in order to be maintained in natural populations, but such benefits through protection against harmful bacterial colonisation have rarely been documented in macroalgae. We found that algae with experimentally impaired defence production, but with an externally controlled epibacterial load, grew significantly better than algae with normal defence production. We also found that undefended algae exposed to a natural epibacterial load experienced a substantial reduction in growth and a 6-fold increase in cell bleaching, compared to controls. Thus, this study provides experimental evidence that chemical defence production in macroalgae is costly, but that the cost is outweighed by fitness benefits provided through protection against harmful bacterial colonisation.     

A comparison of the effectiveness of the four British virus vector species of Longidorus and Xiphinema

The frequency with which the four virus-vector species of longidoroid nematodes occurring in Britain transmitted their associated plant viruses were compared in a series of experiments using a standard procedure. In these tests Xiphinema diversicaudatum proved an effective vector of British isolates of arabis mosaic virus and strawberry latent ringspot virus and Longidorus attenuatus of an isolate of tomato black ring virus from England. In comparison, isolates of raspberry ringspot virus and tomato blackring virus from Scotland and of raspberry ringspot virus from England were transmitted much less readily by their respective vectors, L. elongatus and L. macrosoma. These differences in ability to transmit virus were not related to differences in feeding access on the virus source- or bait-plants, in the extent to which virus was retained within the nematode feeding apparatus or in the frequency with which virus was recovered from Longidorus in concurrent slash tests. Three Scottish isolates of raspberry ringspot and tomato black ring viruses were transmitted equally infrequently by two populations of L. elongatus and the frequency with which virus was transmitted was not greatly increased when the species of source or bait plants was changed.