Experimentation at the interface of fluvial geomorphology, stream ecology and hydraulic engineering and the development of an effective, interdisciplinary river science

One ‘2020 vision’ for fluvial geomorphology is that it sits alongside stream ecology and hydraulic engineering as a key element of an integrated, interdisciplinary river science. A challenge to this vision is that scientists from these three communities may approach problems from different perspectives with different questions and have different methodological outlooks. Refining interdisciplinary methodology is important in this context, but raises a number of issues for geomorphologists, ecologists and engineers alike. In particular, we believe that it is important that there is greater dialogue about the nature of mutually-valued questions and the adoption of mutually-acceptable methods. As a contribution to this dialogue we examine the benefits and challenges of using physical experimentation in flume laboratories to ask interdisciplinary questions. Working in this arena presents the same challenges that experimental geomorphologists and engineers are familiar with (scaling up results, technical difficulties, realism) and some new ones including recognizing the importance of biological processes, identifying hydraulically meaningful biological groups, accommodating the singular behaviour of individuals and species, understanding biological as well as physical stimuli, and the husbandry and welfare of live organisms. These issues are illustrated using two examples from flume experiments designed (1) to understand how the movement behaviours of aquatic insects through the near-bed flow field of gravelly river beds may allow them to survive flood events, and (2) how an understanding of the way in which fish behaviours and swimming capability are affected by flow conditions around artificial structures can lead to the design of effective fish passages. In each case, an interdisciplinary approach has been of substantial mutual benefit and led to greater insights than discipline-specific work would have produced. Looking forward to 2020, several key challenges for experimentalists working on the interface of fluvial geomorphology, stream ecology and hydraulic engineering are identified

Hydrological controls on oviposition habitat are associated with egg-laying phenology of some caddisflies

1. Seasonal variation in resource availability can have strong effects on life histories and population densities. Emergent rocks (ERs) are an essential oviposition resource for multiple species of stream insects. The availability of ERs depends upon water depth and clast size, which vary with discharge and river geomorphology, respectively. Recruitment success for populations may depend on whether peak egg-laying periods occur at times when ER are also abundant. For multiple species that oviposit on ER, we tested whether seasonal fluctuations in ER abundance were concurrent with oviposition phenology. We also tested whether high discharge drowned ERs for sufficiently long periods to preclude egg laying, and whether this problem varied between rivers differing in channel morphology and particle size distribution.2. We obtained a continuous timeseries of water level (WL) measured every 30 min for two years at sites on three rivers in south-eastern Australia with similar hydrology but different geomorphology. A relationship between WL and ER numbers was determined empirically at each site and these relationships were used to predict ER availability over the two years. Egg masses of ten species of caddisflies were enumerated each month for a year in one river to establish oviposition phenology. 3. Abundance of ERs was inversely related to discharge in all three rivers. ERs were most abundant during autumn and scarce during spring. Site-specific geomorphology resulted in skewed or multimodal distributions of ER abundance each year. Between years, catchment-scale hydrometeorology mediated patterns of ER availability, despite the close proximity of sites. Temporal variance in ER availability was not consistently correlated with mean WL or WL variance. ER variance increased with WL variance, when WL was below a threshold equivalent to mean annual WL. Above this threshold, most ER were likely to be submerged.4. Oviposition phenology varied strongly among the ten species of caddisflies, with egg-laying ranging from in 1-2 months to year-round. Temporal variations in ER and egg mass abundance were not correlated for most species. Below a threshold minimum number of ER, egg masses were highly crowded onto the few available ER, which is evidence that ER were in short supply. For five species, high egg mass abundance was positively associated with periods of the year when the time above the threshold number of ERs was high. Unusually, two species laid most egg masses during winter and when the time above this threshold was short. Three species showed no association between egg mass abundance and time above this threshold; two of these species laid eggs year-round.5. Regional hydrometeorology controlled the availability of ERs, but between-river differences were sufficient to deliver different outcomes in the availability of oviposition sites between years and seasons. Caddisflies were rarely prevented from laying eggs but periods when ERs were in short supply created crowding, which may be associated with negative fitness effects on hatching larvae. Geomorphological controls on availability of oviposition resources may have strong implications for the coexistence of species that overlap temporally in egg-laying

Garotas de loja, história social e teoria social [Shop Girls, Social History and Social Theory]

Shop workers, most of them women, have made up a significant proportion of Britain’s labour force since the 1850s but we still know relatively little about their history. This article argues that there has been a systematic neglect of one of the largest sectors of female employment by historians and investigates why this might be. It suggests that this neglect is connected to framings of work that have overlooked the service sector as a whole as well as to a continuing unease with the consumer society’s transformation of social life. One element of that transformation was the rise of new forms of aesthetic, emotional and sexualised labour. Certain kinds of ‘shop girls’ embodied these in spectacular fashion. As a result, they became enduring icons of mass consumption, simultaneously dismissed as passive cultural dupes or punished as powerful agents of cultural destruction. This article interweaves the social history of everyday shop workers with shifting representations of the ‘shop girl’, from Victorian music hall parodies, through modernist social theory, to the bizarre bombing of the Biba boutique in London by the Angry Brigade on May Day 1971. It concludes that progressive historians have much to gain by reclaiming these workers and the service economy that they helped create

International genome-wide meta-analysis identifies new primary biliary cirrhosis risk loci and targetable pathogenic pathways.

Primary biliary cirrhosis (PBC) is a classical autoimmune liver disease for which effective immunomodulatory therapy is lacking. Here we perform meta-analyses of discovery data sets from genome-wide association studies of European subjects (n=2,764 cases and 10,475 controls) followed by validation genotyping in an independent cohort (n=3,716 cases and 4,261 controls). We discover and validate six previously unknown risk loci for PBC (Pcombined<5 × 10(-8)) and used pathway analysis to identify JAK-STAT/IL12/IL27 signalling and cytokine-cytokine pathways, for which relevant therapies exist

Structure of arthropod communities in some saline lakes of central British Columbia

Aquatic arthropods communities were examined with respect to factors determining species distributions and community structure in a series of eight lakes on the Chilcotin Plateau of British Columbia. Climate, altitude, physical location, water temperature and basin shape were similar for all lakes, and although size differed, no evidence was found for the influence of basin morphology on community structure. Salinity and vegetation characteristics differed widely among lakes, so three major processes were investigated: the association of (1) salinity with faunal communities, (2) salinity with floral communities, and (3) faunal with floral communities. These relationships were examined in light of diversity-stability hypotheses. The severity component of environmental stability was represented by salinity, and mean surface water conductivity ranged from 56 to 13115 μS cm-¹ at 25 °C. Salinity variations among lakes were determined primarily by the ions Na, HCO₃, CO₃, C1 and K. Two classification schemes (taxonomic and ecological) and several analytical techniques (community parameters and cluster analysis) indicated that the distribution and structure of faunal and floral communities were related to salinity. In total, 84 arthropod taxa and 26 macrophyte species were found and divided into three groups: those characteristic of high salinities (>5000 μS), of moderate or low salinities (<5000 μS), or tolerant of all salinities. Faunal assemblages in all lakes were dominated by filter feeders, and predators were more abundant in saline lakes. Shredders, collectors and predators were found in all the lakes, but saline lakes had fewer size groups. Floating leaved macrophytes occurred only in freshwater lakes, submerged forms were rare in highly saline lakes, and emergent forms were found in all lakes, although they were less abundant at high salinities. Generally, this study supports the hypothesis that saline habitats have less diverse communities than freshwater ones. In all floral and faunal sample sets, increased salinity was accompanied by a decrease in species richness. Virtually all measures of macrophyte community diversity and productivity were inversely correlated with salinity. Faunal subgroups must be examined separately when measures of community structure incorporate relative abundances. Patterns of association observed in the entire faunal community were dictated by the numerically dominant entomostracan subcommunity, and patterns in other subgroups were masked. Zooplankton trophic level diversity increased with decreasing salinity and changes in community composition were analogous to those of eutrophication. In both coleopteran and hemipteran communities, diversity decreased and density increased with increasing salinity. Possible causal mechanisms structuring each community are hypothesized. Faunal distributions corresponded to their known habitat preferences in terms of macrophyte communities. It was difficult to distinguish between the influence of salinity or macrophyte communities on animal communities as animal communities were often associated with both.Science, Faculty ofZoology, Department ofGraduat

Aquatic versus Terrestrial Insects: Real or Presumed Differences in Population Dynamics?

The study of insect populations is dominated by research on terrestrial insects. Are aquatic insect populations different or are they just presumed to be different? We explore the evidence across several topics. (1) Populations of terrestrial herbivorous insects are constrained most often by enemies, whereas aquatic herbivorous insects are constrained more by food supplies, a real difference related to the different plants that dominate in each ecosystem. (2) Population outbreaks are presumed not to occur in aquatic insects. We report three examples of cyclical patterns; there may be more. (3) Aquatic insects, like terrestrial insects, show strong oviposition site selection even though they oviposit on surfaces that are not necessarily food for their larvae. A novel outcome is that density of oviposition habitat can determine larval densities. (4) Aquatic habitats are often largely 1-dimensional shapes and this is presumed to influence dispersal. In rivers, drift by insects is presumed to create downstream dispersal that has to be countered by upstream flight by adults. This idea has persisted for decades but supporting evidence is scarce. Few researchers are currently working on the dynamics of aquatic insect populations; there is scope for many more studies and potentially enlightening contrasts with terrestrial insects

Aquatic versus Terrestrial Insects: Real or Presumed Differences in Population Dynamics?

The study of insect populations is dominated by research on terrestrial insects. Are aquatic insect populations different or are they just presumed to be different? We explore the evidence across several topics. (1) Populations of terrestrial herbivorous insects are constrained most often by enemies, whereas aquatic herbivorous insects are constrained more by food supplies, a real difference related to the different plants that dominate in each ecosystem. (2) Population outbreaks are presumed not to occur in aquatic insects. We report three examples of cyclical patterns; there may be more. (3) Aquatic insects, like terrestrial insects, show strong oviposition site selection even though they oviposit on surfaces that are not necessarily food for their larvae. A novel outcome is that density of oviposition habitat can determine larval densities. (4) Aquatic habitats are often largely 1-dimensional shapes and this is presumed to influence dispersal. In rivers, drift by insects is presumed to create downstream dispersal that has to be countered by upstream flight by adults. This idea has persisted for decades but supporting evidence is scarce. Few researchers are currently working on the dynamics of aquatic insect populations; there is scope for many more studies and potentially enlightening contrasts with terrestrial insects