• Combining ddPCR and environmental DNA to improve detection capabilities of a critically endangered freshwater invertebrate

      Mauvisseau, Quentin; Davy-Bowker, John; Bulling, Mark; Brys, Rein; Neyrinck, Sabrina; Troth, Christopher; Sweet, Michael; University of Derby; Freshwater Biological Association, Dorset; Natural History Museum, London; et al. (Springer Science and Business Media LLC, 2019-10-01)
      Isogenus nubecula is a critically endangered Plecoptera species. Considered extinct in the UK, I. nubecula was recently rediscovered (in one location of the River Dee, Wales), after 22 years of absence. In a similar way to many other species of Perlodidae, I. nubecula could be utilised as a bio-indicator, for assessing water quality and health status of a given freshwater system. However, conventional monitoring of invertebrates via kick-sampling, is invasive and expensive (time consuming). Further, such methods require a high level of taxonomic expertise. Here, we compared the traditional kick-sampling method with the use of eDNA detection using qPCR and ddPCR-analyses. In spring 2018, we sampled eDNA from twelve locations on the River Dee. I. nubecula was detected using kick-sampling in five of these locations, three locations using both eDNA detection and kick-sampling and one location using eDNA detection alone – resulting in a total of six known and distinct populations of this critically endangered species. Interestingly, despite the eDNA assay being validated in vitro and in silico, and results indicating high sensitivity, qPCR analysis of the eDNA samples proved to be ineffective. In contrast, ddPCR analyses resulted in a clear detection of I. nubecula at four locations suggesting that inhibition most likely explains the large discrepancy between the obtained qPCR and ddPCR results. It is therefore important to explore inhibition effects on any new eDNA assay. We also highlight that ddPCR may well be the best option for the detection of aquatic organisms which are either rare or likely to shed low levels of eDNA into their environment.
    • Ex situ co culturing of the sea urchin, Mespilia globulus and the coral Acropora millepora enhances early post-settlement survivorship

      Craggs, Jamie; Guest, James; Bulling, Mark; Sweet, Michael; University of Derby; Newcastle University (Springer Science and Business Media LLC, 2019-09-10)
      Reef restoration efforts, utilising sexual coral propagation need up-scaling to have ecologically meaningful impact. Post-settlement survival bottlenecks, in part due to competitive benthic algae interactions should be addressed, to improve productivity for these initiatives. Sea urchins are keystone grazers in reef ecosystems, yet feeding behaviour of adults causes physical damage and mortality to developing coral spat. To investigate if microherbivory can be utilised for co-culture, we quantitatively assessed how varying densities of juvenile sea urchins Mespilia globulus (Linnaeus, 1758), reared alongside the coral Acropora millepora (Ehrenberg, 1834) effected survival and growth of coral recruits. Spawning of both species were induced ex situ. A comparison of A. millepora spat reared in three M. globulus densities (low 16.67 m−2, medium 37.50 m−2, high 75.00 m−2) and a non-grazed control indicated coral survival is significantly influenced by grazing activity (p < 0.001) and was highest in the highest density treatment (39.65 ± 10.88%, mean ± s.d). Urchin grazing also significantly (p < 0.001) influenced coral size (compared to non-grazing control), with colonies in the medium and high-densities growing the largest (21.13 ± 1.02 mm & 20.80 ± 0.82, mean ± s.e.m). Increased urchin density did however have a negative influence on urchin growth, a result of limited food availability.
    • Influence of accuracy, repeatability and detection probability in the reliability of species-specific eDNA based approaches

      Mauvisseau, Quentin; Burian, Alfred; Gibson, Ceri; Brys, Rein; Ramsey, Andrew; Sweet, Michael; University of Derby; Freshwater Biological Association, Cumbria; Research Institute for Nature and Forest, Belgium (Springer, 2019-01-24)
      Environmental DNA (eDNA) barcoding has a high potential to increase the cost-efficiency of species detection and monitoring in aquatic habitats. However, despite vast developments in the field, many published assays often lack detailed validation and there is little to no commonly (agreed upon) standardization of protocols. In this study, we evaluated the reliability of eDNA detection and quantification using published primers and assays targeting the Freshwater Pearl Mussel as a model organism. We first assessed limits of detection for two different target genes (COI and 16S) following the MIQE guidelines, and then tested the reliability of quantification in a double-blind mesocosm experiment. Our results reveal that different methodological indicators, namely accuracy, repeatability and detection probability affected the reliability of eDNA measurement at the different levels tested. The selection of the optimal analytical method was mainly determined by detection probability. Both the COI and 16S assays were highly specific for the targeted organism and showed similar accuracy and repeatability, whilst the limit of detection was clearly lower for the COI based approach. In contrast, the reliability of eDNA quantification hinged on repeatability, reflected by the scattering (r2 = 0.87) around the relationship between eDNA and mussel density in mesocosms. A bootstrapping approach, which allowed for the assignment of measures associated with repeatability of samples, revealed that variability between natural replicates (i.e. accuracy) strongly influenced the number of replicates required for a reliable species detection and quantification in the field.
    • Elemental ratios link environmental change and human health

      Paseka, Rachel E.; Bratt, Anika R.; MacNeill, Keeley L.; Burian, Alfred; See, Craig R.; University of Derby (Frontiers, 2019-10-10)
      Humans have fundamentally altered the cycling of multiple elements on a global scale. These changes impact the structure and function of terrestrial and aquatic ecosystems, with many implications for human health. Most prior studies linking biogeochemical changes to human health have evaluated the effects of single elements in isolation. However, the relative availability of multiple elements often determines the biological impact of shifts in the concentration of a single element. The balance of multiple elements is the focus of ecological stoichiometry, which highlights the importance of elemental ratios in biological function across all systems and scales of organization. Consequently, ecological stoichiometry is a promising framework to inform research on the links between global changes to elemental cycles and human health. We synthesize evidence that elemental ratios link global change with human health through biological processes occurring at two scales: in the environment (natural ecosystems and food systems) and within the human body. Elemental ratios in the environment impact the key ecosystem processes of productivity and biodiversity, both of which contribute to the production of food, toxins, allergens, and parasites. Elemental ratios in diet impact processes within the human body, including the function and interactions of the immune system, parasites, and the non-pathogenic microbiome. Collectively, these stoichiometric effects contribute to a wide range of non-infectious and infectious diseases. By describing stoichiometric mechanisms linking global change, ecological processes, and human health, we hope to inspire future empirical and theoretical research on this theme.
    • A community-based evaluation of population growth and agro-pastoralist resilience in Sub-Saharan drylands

      Karaya, Rebecca; Wernersson, Julia E.V.; Egberth, Mikael; Lokorwa, Benjamin; Nyberg, Gert; Alfred, Burian; University of Derby (Elsevier, 2018-12-14)
      Human population growth is considered together with climate warming as major driver of change in Sub-Saharan Africa. Research on the implications of increased population densities often utilises community knowledge but without incorporating the view of local stakeholders. In this study, we applied a community-centred approach to assess direct and indirect consequences of population growth in drylands of north-western Kenya. Combined social, agricultural and geo-spatial analyses allowed us to identify major system transitions, determine their linkage to population growth and deduce consequences for local livelihoods and community resilience.Community-members reported positive and negative consequences of fourfold population growth since 1974 but evaluated its overall effect as clearly beneficial. This overall positive effect was based on both, positive developments and the successful mitigation of potential system stressors. First, food security was maintained despite high growth rates because a shift from migratory pastoralism to a more labour-intensive agro-pastoralist system helped to increase agricultural productivity. Additionally, land-use changes were linked to land privatisation and improved erosion protection on private land, decoupling population growth from environmental degradation.We detected, however also early warning signs of reduced community resilience as households were unable to fully recover livestock densities after catastrophic events. A population-growth driven reduction in household land-sizes and the decreased monetary value of agricultural production were identified as drivers of this development. The extrapolation of our results to establish a general relationship between population densities, land-use and household resilience in Sub-Saharan drylands suggest that further system transformations will be required to ensure regional food-security.
    • Nutrient deficiencies and the restriction of compensatory mechanisms in copepods

      Burian, Alfred; Grosse, Julia; Winder, Monika; Boschker, Henricus T.S.; Stockholm University; Utrecht University (British Ecological Society, 2017-11-14)
      The flexible regulation of feeding behaviour and nutrient metabolism is a prerequisite for consumers to grow and survive under variable food conditions. Thus, it is essential to understand the ecological trade-offs that restrict regulatory mechanisms in consumers to evaluate the consequences of nutrient limitations for trophic interactions. Here, we assessed behavioural and physiological adjustments to nutrient deficiencies in copepods and examined whether energy limitation, food digestibility or co-limitation with a second nutrient restricted compensatory mechanisms. A combination of C-13-labelling and compound-specific stable isotope measurements revealed that copepods compensated nitrogen deficiencies by raising retention efficiencies of amino acids (AA). The costs of higher retention efficiencies were reflected in the doubling of structural fatty acids (FA), probably required for morphological adaptations of the gut. A depletion of highly unsaturated FA in storage lipids and their selective retention suggested that these FA became co-limiting and restricted a further increase in AA retention efficiencies. Copepods feeding on phosphorus-limited algae showed a marked increase in ingestion rates but were not fully able to compensate dietary deficiencies. The increase in ingestion rates was thereby not restricted by higher foraging costs because energy storage in copepods increased. Instead, thicker cell walls of nutrient-limited algae indicated that algal digestion resistance restricted the extent of surplus feeding. The strongly nutrient-specific response of copepods had large implications for recycling rates, growth efficiencies and the potential top-down control at the plant-animal interface. Compensatory mechanisms to mitigate nutrient deficiencies are therefore an essential aspect of trophic interactions and have the potential to alter the structure of food web.
    • Use of environmental management systems to mitigate urban pollution

      Horry, Rosemary; University of Derby; University of West of England (Wiley, 2018-10-16)
      An environmental management system (EMS) is an instrument that can help organizations to manage and positively improve their level of impact on the environment. This chapter provides an overview of the importance for organizations to have an established EMS in place. It employs a series of infamous case studies to highlight where an EMS could have served as a useful means of mitigating pollution events. The chapter identifies a number of organizational benefits of implementing an EMS. All businesses face a challenge in terms of their environmental impacts; environmental work is not just a concern for multinational organizations, which is sometimes how it is viewed. The chapter describes some of the well known pollution incidents and how they were managed. Some of these impacts were mitigated through the use of legislation.
    • Madagascar's escape from Africa: A high-resolution plate reconstruction for the Western Somali Basin and implications for supercontinent dispersal

      Phethean, Jordan; Kalnins, Lara M.; van Hunen, Jeroen; Biffi, Paolo G.; Davies, Richard J.; McCaffrey, Ken J.W.; Durham University; University of Edinburgh; S.G.E.G ENI, Milan, Italy; Newcastle University (American Geophysical Union (AGU), 2016-12-29)
      Accurate reconstructions of the dispersal of supercontinent blocks are essential for testing continental breakup models. Here, we provide a new plate tectonic reconstruction of the opening of the Western Somali Basin during the breakup of East and West Gondwana. The model is constrained by a new comprehensive set of spreading lineaments, detected in this heavily sedimented basin using a novel technique based on directional derivatives of free‐air gravity anomalies. Vertical gravity gradient and free‐air gravity anomaly maps also enable the detection of extinct mid‐ocean ridge segments, which can be directly compared to several previous ocean magnetic anomaly interpretations of the Western Somali Basin. The best matching interpretations have basin symmetry around the M0 anomaly; these are then used to temporally constrain our plate tectonic reconstruction. The reconstruction supports a tight fit for Gondwana fragments prior to breakup, and predicts that the continent‐ocean transform margin lies along the Rovuma Basin, not along the Davie Fracture Zone (DFZ) as commonly thought. According to our reconstruction, the DFZ represents a major ocean‐ocean fracture zone formed by the coalescence of several smaller fracture zones during evolving plate motions as Madagascar drifted southwards, and offshore Tanzania is an obliquely rifted, rather than transform, margin. New seismic reflection evidence for oceanic crust inboard of the DFZ strongly supports these conclusions. Our results provide important new constraints on the still enigmatic driving mechanism of continental rifting, the nature of the lithosphere in the Western Somali Basin, and its resource potential.
    • Evidence for basement reactivation during the opening of the Labrador sea from the Makkovik province, Labrador, Canada: insights from field data and numerical models

      Peace, Alexander; Dempsey, Edward; Schiffer, Christian; Welford, J.; McCaffrey, Ken; Imber, Jonathan; Phethean, Jordan; Durham University; Memorial University of Newfoundland, Canada; University of Hull; et al. (MDPI AG, 2018-08-20)
      The onshore exposures adjacent to modern, offshore passive continental margins may preserve evidence of deformation from the pre-, syn-, and post-rift phases of continental breakup that allow us to investigate the processes associated with and controlling rifting and breakup. Here, we characterize onshore brittle deformation and pre-rift basement metamorphic mineral fabric from onshore Labrador in Eastern Canada in the Palaeoproterozoic Aillik Domain of the Makkovik Province. Stress inversion (1) was applied to these data and then compared to (2) numerical models of hybrid slip and dilation tendency, (3) independent calculations of the regional geopotential stress field, and (4) analyses of palaeo-stress in proximal regions from previous work. The stress inversion shows well-constrained extensional deformation perpendicular to the passive margin, likely related to pre-breakup rifting in the proto-Labrador Sea. Hybrid slip and dilatation analysis indicates that inherited basement structures were likely oriented in a favorable orientation to be reactivated during rifting. Reconstructed geopotential stresses illuminate changes of the ambient stress field over time and confirm the present paleo-stress estimates. The new results and numerical models provide a consistent picture of the late Mesozoic-Cenozoic lithospheric stress field evolution in the Labrador Sea region. The proto-Labrador Sea region was characterized by a persistent E–W (coast-perpendicular) extensional stress regime, which we interpret as the pre-breakup continental rifting that finally led to continental breakup. Later, the ridge push of the Labrador Sea spreading ridge maintained this general direction of extension. We see indications for anti-clockwise rotation of the direction of extension along some of the passive margins. However, extreme persistent N–S-oriented extension as indicated by studies further north in West Greenland cannot be confirmed.
    • An evaluation of Mesozoic rift-related magmatism on the margins of the Labrador Sea : implications for rifting and passive margin asymmetry.

      Phethean, Jordan; Peace, Alexander; McCaffrey, Ken; Imber, Jonathan; Nowell, Geoff; Gerdes, Keith; Dempsey, Edward; Durham University; Shell International (The Geological Society of America, 2016-09-29)
      The Labrador Sea is a small (~900 km wide) ocean basin separating southwest Greenland from Labrador, Canada. It opened following a series of rifting events that began as arly as the Late Triassic or Jurassic, culminating in a brief period of seafloor spreading commencing by polarity chron 27 (C27; Danian) and ending by C13 (Eocene-Oligocene oundary). Rift-related magmatism has been documented on both conjugate margins of the Labrador Sea. In southwest Greenland this magmatism formed a major coast-parallel dike swarm as well as other smaller dikes and intrusions. Evidence for rift-related magmatism on the conjugate Labrador margin is limited to igneous lithologies found in deep offshore exploration wells, mostly belonging to the Alexis Formation, along with a postulated Early Cretaceous nephelinite dike swarm (ca. 142 Ma) that crops out onshore, near Makkovik, Labrador. Our field observations of this Early Cretaceous nephelinite suite lead us to conclude that the early rift-related magmatism exposed around Makkovik is volumetrically and spatially limited compared to the contemporaneous magmatism on the conjugate southwest Greenland margin. This asymmetry in the spatial extent of the exposed onshore magmatism is consistent with other observations of asymmetry between the conjugate margins of the Labrador Sea, including the total sediment thickness in offshore basins, the crustal structure, and the bathymetric profile of the shelf width. We propose that the magmatic and structural asymmetry observed between these two conjugate margins is consistent with an early rifting phase dominated by simple shear rather than pure shear deformation. In such a setting Labrador would be the lower plate margin to the southwest Greenland upper plate.
    • The Jan Mayen microplate complex and the Wilson cycle

      Schiffer, Christian; Peace, Alexander; Phethean, Jordan; Gernigon, Laurent; McCaffrey, Ken; Petersen, Kenni D.; Foulger, Gillian; Durham University; Memorial University of Newfoundland, Canada; Geological Survey of NorwayLeiv; et al. (Geological Society of London, 2018-02-01)
      The opening of the North Atlantic region was one of the most important geodynamic events that shaped the present day passive margins of Europe, Greenland and North America. Although well-studied, much remains to be understood about the evolution of the North Atlantic, including the role of the Jan Mayen microplate complex. Geophysical data provide an image of the crustal structure of this microplate and enable a detailed reconstruction of the rifting and spreading history. However, the mechanisms that cause the separation of microplates between conjugate margins are still poorly understood. We assemble recent models of rifting and passive margin formation in the North Atlantic and discuss possible scenarios that may have led to the formation of the Jan Mayen microplate complex. This event was probably triggered by regional plate tectonic reorganizations rejuvenating inherited structures. The axis of rifting and continental break-up and the width of the Jan Mayen microplate complex were controlled by old Caledonian fossil subduction/suture zones. Its length is related to east–west-oriented deformation and fracture zones, possibly linked to rheological heterogeneities inherited from the pre-existing Precambrian terrane boundaries.
    • A review of Pangaea dispersal and large igneous provinces – In search of a causative mechanism

      Peace, A.L.; Phethean, Jordan; Franke, D.; Foulger, G.R.; Schiffer, C.; Welford, J.K.; McHone, G.; Rocchi, S.; Schnabel, M.; Doré, A.G.; et al. (Elsevier, 2019-07-22)
      The breakup of Pangaea was accompanied by extensive, episodic, magmatic activity. Several Large Igneous Provinces (LIPs) formed, such as the Central Atlantic Magmatic Province (CAMP) and the North Atlantic Igneous Province (NAIP). Here, we review the chronology of Pangaea breakup and related large-scale magmatism. We review the Triassic formation of the Central Atlantic Ocean, the breakup between East and West Gondwana in the Middle Jurassic, the Early Cretaceous opening of the South Atlantic, the Cretaceous separation of India from Antarctica, and finally the formation of the North Atlantic in the Mesozoic-Cenozoic. We demonstrate that throughout the dispersal of Pangaea, major volcanism typically occurs distal from the locus of rift initiation and initial oceanic crust accretion. There is no location where extension propagates away from a newly formed LIP. Instead, LIPs are coincident with major lithosphere-scale shear movements, aborted rifts and splinters of continental crust rifted far out into the oceanic domain. These observations suggest that a fundamental reappraisal of the causes and consequences of breakup-related LIPs is in order.
    • Slow on the draw: the representation of turtles, terrapins and tortoises in children’s literature

      Beaumont, Ellen S.; Briers, Erin; Harrison, Emma; University of Derby; The Orkney Campus of Heriot-Watt University, Stromness (Springer, 2019-08-08)
      Children’s picture books, both fiction and non-fiction, play a vital role in introducing the reader to the natural world. Here we examine the representation of turtles, terrapins and tortoises (Testudines) in 204 English language picture books and find a mean of 3.9 (SD 9.1) basic biological errors per book. Only 83 (40.7%) of the examined books were found to be error-free in the representation of Testudines, with no significant improvement in biological accuracy being observed over time (book publication date range 1974–2017). Suggestions are made as to how biological accuracy of children’s literature could be improved to help foster children’s understanding and wonder of the natural world. Fantasy and imagination have an important role within children’s literature, but here it is argued that the books children read should support future generations having sufficient understanding of the natural world to imagine the solutions to current environmental problems. A role of children’s picture books should not be to reinforce biological illiteracy.
    • Lower crustal heterogeneity and fractional crystallisation control evolution of small volume magma batches at ocean island volcanoes (Ascension Island, South Atlantic)

      Chamberlain, Katy J.; Barclay, Jenni; Preece, Katie; Brown, Richard J.; Davidson, Jon P.; Durham University; University of Derby; University of East Anglia; Swansea University (Oxford University Press, 2019-08-10)
      Ocean island volcanoes erupt a wide range of magmatic compositions via a diverse range of eruptive styles. Understanding where and how these melts evolve is thus an essential component in the anticipation of future volcanic activity. Here we examine the role of crustal structure and magmatic flux in controlling the location, evolution and ultimately composition of melts at Ascension Island. Ascension Island, in the south Atlantic, is an ocean island volcano which has produced a continuum of eruptive compositions from basalt to rhyolite in its 1-million-year subaerial eruptive history. Volcanic rocks broadly follow a silica undersaturated subalkaline evolutionary trend and new data presented here show a continuous compositional trend from basalt through trachyte to rhyolite. Detailed petrographic observations are combined with in-situ geochemical analyses of crystals and glass, and new whole rock major and trace element data from mafic and felsic pyroclastic and effusive deposits that span the entire range in eruptive ages and compositions found on Ascension Island. These data show that extensive fractional crystallisation is the main driver for the production of felsic melt for Ascension Island; a volcano built on thin, young, oceanic crust. Strong spatial variations in the compositions of erupted magmas reveals the role of a heterogeneous lower crust: differing degrees of interaction with a zone of plutonic rocks are responsible for the range in mafic lava composition, and for the formation of the central and eastern felsic complexes. A central core of nested small-scale plutonic, or mush-like, bodies inhibits the ascent of mafic magmas, allowing sequential fractional crystallisation within the lower crust, and generating felsic magmas in the core of the island. There is no evidence for magma mixing preserved in any of the studied eruptions, suggesting that magma storage regions are transient, and material is not recycled between eruptions.
    • Growth rate, extinction and survival amongst late Cenozoic bivalves of the North Atlantic

      Johnson, Andrew L. A.; Harper, Elizabeth M.; Clarke, Abigail; Featherstone, Aaron C.; Heywood, Daniel J.; Richardson, Kathryn E.; Spink, Jack O.; Thornton, Luke A.H.; University of Derby (Taylor & Francis, 2019-09-12)
      Late Cenozoic bivalve extinction in the North Atlantic and adjacent areas has been attributed to environmental change (declines in temperature and primary production). Within scallops and oysters—bivalve groups with a high growth rate—certain taxa which grew exceptionally fast became extinct, while others which grew slower survived. The taxa which grew exceptionally fast would have obtained protection from predators thereby, so their extinction may have been due to the detrimental effect of environmental change on growth rate and ability to avoid predation, rather than environmental change per se. We investigated some glycymeridid and carditid bivalves—groups with a much lower growth rate than scallops and oysters—to see whether extinct forms from the late Cenozoic of the North Atlantic grew faster than extant forms, and hence whether their extinction may also have been mediated by increased mortality due to predation. Growth rate was determined from the cumulative width of annual increments in the hinge area; measurements were scaled up to overall shell size for the purposes of comparison with data from living species. Growth of the extinct glycymeridid Glycymeris subovata was at about the same rate as the slowest-growing living glycymeridid and much slower than in late Cenozoic samples of extant G. americana, in which growth was at about the same rate as the fastest-growing living glycymeridid. Growth of extinct G. obovata was also slower than G. americana, and that of the extinct carditid Cardites squamulosa ampla similarly slow (evidently slower than in the one living carditid species for which data are available). These findings indicate that within bivalve groups whose growth is much slower than scallops and oysters, extinction or survival of taxa through the late Cenozoic was not influenced by whether they were relatively fast or slow growers. By implication, environmental change acted directly to cause extinctions in slow-growing groups, rather than by increasing susceptibility to predation.
    • Bridging the gap: 40Ar/39Ar dating of volcanic eruptions from the ‘Age of Discovery’

      Preece, Katie; Mark, Darren F.; Barclay, Jenni; Cohen, Benjamin E.; Chamberlain, Katy J.; Jowitt, Claire; Vye-Brown, Charlotte; Brown, Richard J.; Hamilton, Scott; Isotope Geoscience Unit, Scottish Universities Environmental Research Centre, East Kilbride; et al. (Geological Society of America, 2018-11-09)
      Many volcanoes worldwide still have poorly resolved eruption histories, with the date of the last eruption often undetermined. One such example is Ascension Island, where the timing of the last eruption, and consequently, the activity status of the volcano, is unclear. Here, we use the 40Ar/39Ar dating technique to resolve ages of the three youngest lava flows on the island, which are hawaiites and mugearite with 1.5 – 1.9 wt% K2O. In dating these lavas, we provide the first evidence of Holocene volcanic activity on Ascension (0.51 ± 0.18 ka; 0.55 ± 0.12 ka; 1.64 ± 0.37 ka), determining that it should be classed as an active volcanic system. In addition, we demonstrate that the 40Ar/39Ar method can reproducibly date mafic lava flows younger than 1 ka, decreasing the gap between recorded history and geological dating. These results offer new prospects for determining patterns of late-Holocene volcanic activity; critical for accurate volcanic hazard assessment.
    • Analogue Modeling of Plate Rotation Effects in Transform Margins and Rift‐Transform Intersections

      Farangitakis, Georgios-Pavlos; Sokoutis, D; McCaffrey, Kenneth; Willingshofer , Ernst; Kalnins, Lara; Phethean, Jordan; van Hunen, Jeroen; van steen, V; University of Durham; University of Oslo; et al. (Wiley, 2019-01-29)
      Transform margins are first‐order tectonic features that accommodate oceanic spreading. Uncertainties remain about their evolution, genetic relationship to oceanic spreading, and general structural character. When the relative motion of the plates changes during the margin evolution, further structural complexity is added. This work investigates the evolution of transform margins and associated rift‐transform intersections, using an analogue modeling approach that simulates changing plate motions. We investigate the effects of different crustal rheologies by using either (a) a two‐layer brittle‐ductile configuration to simulate upper and lower continental crust, or (b) a single layer brittle configuration to simulate oceanic crust. The modeled rifting is initially orthogonal, followed by an imposed plate vector change of 7° that results in oblique rifting and plate overlap (transpression) or underlap (transtension) along each transform margin. This oblique deformation reactivates and overprints earlier orthogonal structures and is representative of natural examples. We find that (a) a transtensional shift in the plate direction produces a large strike‐slip principal displacement zone, accompanied by en‐echelon oblique‐normal faults that accommodate the horizontal displacement until the new plate motion vector is stabilized, while (b) a transpressional shift produces compressional structures such as thrust fronts in a triangular zone in the area of overlap. These observations are in good agreement with natural examples from the Gulf of California (transtensional) and Tanzania Coastal Basin (transpressional) shear margins and illustrate that when these deformation patterns are present, a component of plate vector change should be considered in the evolution of transform margins.
    • Urban meadows as an alternative to short mown grassland: effects of composition and height on biodiversity

      Norton, Briony, A.; Bending, Gary, D.; Clark, Rachel; Corstanje, Ron; Dunnett, Nigel; Evans, Karl, L.; Grafius, Darren, R.; Gravestock, Emily; Grice, Samuel, M.; Harris, Jim, A.; et al. (Ecological Society of America, 2019-07-22)
      There are increasing calls to provide greenspace in urban areas, yet the ecological quality, as well as quantity, of greenspace is important. Short mown grassland designed for recreational use is the dominant form of urban greenspace in temperate regions but requires considerable maintenance and typically provides limited habitat value for most taxa. Alternatives are increasingly proposed, but the biodiversity potential of these is not well understood. In a replicated experiment across six public urban greenspaces, we used nine different perennial meadow plantings to quantify the relative roles of floristic diversity and height of sown meadows on the richness and composition of three taxonomic groups: plants, invertebrates, and soil microbes. We found that all meadow treatments were colonized by plant species not sown in the plots, suggesting that establishing sown meadows does not preclude further locally determined grassland development if management is appropriate. Colonizing species were rarer in taller and more diverse plots, indicating competition may limit invasion rates. Urban meadow treatments contained invertebrate and microbial communities that differed from mown grassland. Invertebrate taxa responded to changes in both height and richness of meadow vegetation, but most orders were more abundant where vegetation height was longer than mown grassland. Order richness also increased in longer vegetation and Coleoptera family richness increased with plant diversity in summer. Microbial community composition seems sensitive to plant species composition at the soil surface (0–10 cm), but in deeper soils (11–20 cm) community variation was most responsive to plant height, with bacteria and fungi responding differently. In addition to improving local residents’ site satisfaction, native perennial meadow plantings can produce biologically diverse grasslands that support richer and more abundant invertebrate communities, and restructured plant, invertebrate, and soil microbial communities compared with short mown grassland. Our results suggest that diversification of urban greenspace by planting urban meadows in place of some mown amenity grassland is likely to generate substantial biodiversity benefits, with a mosaic of meadow types likely to maximize such benefits.
    • The use of animal-borne cameras to video-track the behaviour of domestic cats.

      Huck, Maren; Watson, Samantha; University of Derby; Manchester Metropolitan University (Elsevier, 2019-05-07)
      Free roaming domestic animals can have a profound effect on wildlife. To better understand and mitigate any impact, it is important to understand the behaviour patterns of the domestic animals, and how other variables might influence their behaviour. Direct observation is not always feasible and bears the potential risk of observer effects. The use of animal-borne small videocameras provides the opportunity to study behaviour from the animal’s point of view. While video-tracking has been used previously to study specific aspects of the behaviour of a species, it has not been used so far to determine detailed time-budgets. The aim of this study was to provide and validate an ethogram based on cat-camera footage collected from 16 cats (Felis catus). The methodology was validated comparing films recorded simultaneously, from both collar-mounted video recorders and hand-held video recorders. Additionally, the inter-observer reliability of scorers was measured. Continuous and instantaneous recording regimes were compared, and behavioural accumulation curves were evaluated to provide further technique recommendations for video-tracking cats. Video-tracking allows scoring of behaviour as reliably as direct observation (linear mixed effects model: t<0.001, P = 0.99; df= 14 in 7 cats; Cohen's κ =0.88). Furthermore, interobserver reliability was high (Cohen's κ = 0.72) and was not significantly different from 0.8 (one-sample t-test: t=1.15. df=5, P = 0.30), indicating that the method is not subject to bias in observers. Recommendations are given for the most efficient scoring protocol to reliably record feline behaviour. While the validation was concerned with cat behaviour, the approach can be easily adapted for a variety of domestic species, as well as some captive animals. Video-tracking offers a new avenue to investigate both general time-budgets and more specific behaviours such as foraging or space use from the animal's point of view and in its normal environment, without restrictions to movement. Insights gained through video-tracking will be relevant to various conservation and animal welfare issues.
    • Using GIS-linked Bayesian Belief Networks as a tool for modelling urban biodiversity.

      Corstanje, Ron; Warren, Philip H.; Evans, Karl L.; Siriwardena, Gavin M.; Pescott, Oliver L.; Plummer, Kate E.; Mears, Meghann; Zawadzka, Joanna; Richards, J. Paul; Harris, Jim A.; et al. (Elsevier, 2019-05-30)
      The ability to predict spatial variation in biodiversity is a long-standing but elusive objective of landscape ecology. It depends on a detailed understanding of relationships between landscape and patch structure and taxonomic richness, and accurate spatial modelling. Complex heterogeneous environments such as cities pose particular challenges, as well as heightened relevance, given the increasing rate of urbanisation globally. Here we use a GIS-linked Bayesian Belief Network approach to test whether landscape and patch structural characteristics (including vegetation height, green-space patch size and their connectivity) drive measured taxonomic richness of numerous invertebrate, plant, and avian groups. We find that modelled richness is typically higher in larger and better-connected green-spaces with taller vegetation, indicative of more complex vegetation structure and consistent with the principle of ‘bigger, better, and more joined up’. Assessing the relative importance of these variables indicates that vegetation height is the most influential in determining richness for a majority of taxa. There is variation, however, between taxonomic groups in the relationships between richness and landscape structural characteristics, and the sensitivity of these relationships to particular predictors. Consequently, despite some broad commonalities, there will be trade-offs between different taxonomic groups when designing urban landscapes to maximise biodiversity. This research demonstrates the feasibility of using a GIS-coupled Bayesian Belief Network approach to model biodiversity at fine spatial scales in complex landscapes where current data and appropriate modelling approaches are lacking, and our findings have important implications for ecologists, conservationists and planners.