• There were no large volumes of felsic continental crust in the early Earth

      Rollinson, Hugh; University of Derby (Geological Society of America, 2017-02-17)
      New model growth curves for the continental crust based upon Hf-isotopes in zircon suggest that large volumes of felsic continental crust were present in the Hadean and early Archaean. These models sit uncomfortably with estimates of the volume of ancient crust preserved today and imply that the large volumes of crust that were created early in Earth history are now lost. However, this paper argues that there is no evidence from modern mantle geochemistry that very large volumes of early continental crust have been recycled into the mantle. In contrast significant volumes of Archaean crust may have been reworked into younger crust, although there is no evidence that this process took place in the early Archaean and Hadean. Geological evidence from the detrital zircon record does not show evidence for large volumes of very early felsic crust, rather, geochemical proxies for Eo-Archaean and Hadean crust strongly suggest that the earliest crusts on Earth, some of which may have been subaerial, were mafic. A lack of very early felsic crust on Earth calls for a re-evaluation of current crustal growth curves and geodynamic models for the start of plate tectonics, the role of supercontinents in early continent formation and the role of the subcontinental lithosphere in continent preservation. The earliest felsic rocks on Earth may have taken the form of oceanic plagiogranites or ocean-island potassic granites as found in the modern.
    • Till death (or an intruder) do us part: intrasexual-competition in a monogamous Primate

      Fernández-Duque, Eduardo; Huck, Maren; University of Pennsylvania, Department of Anthropology; Centro de Ecologia Aplicada del Litoral, CONICET (2013)
      Polygynous animals are often highly dimorphic, and show large sex-differences in the degree of intra-sexual competition and aggression, which is associated with biased operational sex ratios (OSR). For socially monogamous, sexually monomorphic species, this relationship is less clear. Among mammals, pair-living has sometimes been assumed to imply equal OSR and low frequency, low intensity intra-sexual competition; even when high rates of intra-sexual competition and selection, in both sexes, have been theoretically predicted and described for various taxa. Owl monkeys are one of a few socially monogamous primates. Using long-term demographic and morphological data from 18 groups, we show that male and female owl monkeys experience intense intra-sexual competition and aggression from solitary floaters. Pair-mates are regularly replaced by intruding floaters (27 female and 23 male replacements in 149 group-years), with negative effects on the reproductive success of both partners. Individuals with only one partner during their life produced 25% more offspring per decade of tenure than those with two or more partners. The termination of the pair-bond is initiated by the floater, and sometimes has fatal consequences for the expelled adult. The existence of floaters and the sporadic, but intense aggression between them and residents suggest that it can be misleading to assume an equal OSR in socially monogamous species based solely on group composition. Instead, we suggest that sexual selection models must assume not equal, but flexible, context-specific, OSR in monogamous species.
    • Topographic shading influences cryoconite morphodynamics and carbon exchange.

      Cook, J. M.; Sweet, Michael J.; Cavalli, Ottavia; Taggart, Angus; Edwards, Arwyn; University of Derby; Aberystwyth University; University of Sheffield (Taylor and Francis, 2018-03-13)
      Cryoconite holes are the most active and diverse microbial habitats on glacier and ice-sheet surfaces. In this article the authors demonstrate that the shape of cryoconite holes varies depending on ice-surface topography and that this has implications for the carbon cycling regime within. Net ecosystem production is shown to be controlled primarily by sediment thickness within holes. The authors show that irregular hole shapes are indicative of hole migration away from topographic shade, which promotes carbon fixation at the mesoscale on ice surfaces. A cellular automaton is used in conjunction with sediment-delivery experiments to show that migration is the result of simple sediment transfer processes, implying a relationship between ice-surface evolution and cryoconite biogeochemistry that has not previously been examined.
    • Topographic shading influences cryoconite morphodynamics and carbon exchange.

      Cook, J. M.; Sweet, Michael J.; Cavalli, O.; Taggart, A.; Edwards, A.; University of Derby; University of Sheffield; Aberystwyth University; Department of Geography, University of Sheffield, Sheffield, UK; Environmental Sustainability Research Centre, College of Life and Natural Science, University of Derby, Derby, UK; et al. (Taylor & Francis., 2018-03-13)
      Cryoconite holes are the most active and diverse microbial habitats on glacier and ice-sheet surfaces. In this article the authors demonstrate that the shape of cryoconite holes varies depending on ice-surface topography and that this has implications for the carbon cycling regime within. Net ecosystem production is shown to be controlled primarily by sediment thickness within holes. The authors show that irregular hole shapes are indicative of hole migration away from topographic shade, which promotes carbon fixation at the mesoscale on ice surfaces. A cellular automaton is used in conjunction with sediment-delivery experiments to show that migration is the result of simple sediment transfer processes, implying a relationship between ice-surface evolution and cryoconite biogeochemistry that has not previously been examined.
    • Tracing the origin of olive ridley turtles entangled in ghost nets in the Maldives: A phylogeographic assessment of populations at risk

      Stelfox, Martin; Burian, Alfred; Shanker, Kartik; Rees, Alan F.; Jean, Claire; Willson, Maïa S.; Manik, Nashwa Ahmed; Sweet, Michael; University of Derby; Olive Ridley Project, 11 Dane Close, Bramhall, Stockport, Cheshire; et al. (Elsevier BV, 2020-04-07)
      Abandoned, lost or discarded fishing nets, (ghost nets) represent a major threat to marine vertebrates. However, thorough assessments of their impact on threatened species are largely missing. In the Maldives, olive ridley sea turtles (Lepidochelys olivacea) are frequently caught in ghost nets however the archipelago does not support a significant nesting population. Our aim in this study was to determine the origin of olive ridleys entangled in ghost nets found in the Maldives and evaluate potential impacts on respective source populations. Based on a citizen science and conservation program, we recorded 132 olive ridley turtles entangled in ghost nets in just one year. Genetic analyses (mtDNA) of entangled individuals and of potential source populations revealed that most captured olive ridleys originated from Sri Lanka and eastern India. Oman could be excluded as source population, even during the prevalence of the south west monsoon. Based on our results and already available published literature, we were able to estimate that the recorded ghost net entanglements accounted for a relatively small amount (0.48%) of the eastern Indian population. However, the entangled turtles accounted for a much larger percentage (41%) of the Sri Lankan populations. However, it should be noted that our estimates of population-level mortality are linked to substantial uncertainty due to the lack of reliable information on population dynamics. Consequently, any precautionary protection measures applied should be complemented with improved quantification of turtle recruitment and life-stage specific mortalities.
    • Transcriptomes and expression profiling of deep-sea corals from the Red Sea provide insight into the biology of azooxanthellate corals

      Yum, Lauren K.; Baumgarten, Sebastian; Röthig, Till; Roder, Cornelia; Roik, Anna; Michell, Craig; Voolstra, Christian R.; King Abdullah University of Science and Technology (KAUST) (Nature Research, 2017-07-25)
      Despite the importance of deep-sea corals, our current understanding of their ecology and evolutionis limited due to difficulties in sampling and studying deep-sea environments. Moreover, a recent reevaluation of habitat limitations has been suggested after characterization of deep-sea corals in the Red Sea, where they live at temperatures of above 20 °C at low oxygen concentrations. To gain further insight into the biology of deep-sea corals, we produced reference transcriptomes and studied gene expression of three deep-sea coral species from the Red Sea, i.e. Dendrophyllia sp., Eguchipsammia fistula, and Rhizotrochus typus. Our analyses suggest that deep-sea coral employ mitochondrial hypometabolism and anaerobic glycolysis to manage low oxygen conditions present in the Red Sea. Notably, we found expression of genes related to surface cilia motion that presumably enhance small particle transport rates in the oligotrophic deep-sea environment. This is the first study to characterize transcriptomes and in situ gene expression for deep-sea corals. Our work offers several mechanisms by which deep-sea corals might cope with the distinct environmental conditions present in the Red Sea. As such, our data provides direction for future research and further insight to organismal response of deep sea coral to environmental change and ocean warming.
    • Trevorite: Ni-rich spinel formed by metasomatism and desulfurization processes at Bon Accord, South Africa?

      O'Driscoll, Brian; Clay, Patricia L.; Cawthorn, R. Grant; Lenaz, Davide; Adetunji, Jacob; Kronz, Andreas; Keele University; University of Manchester; University of the Witwatersrand; Trieste University; et al. (Mineralogical Society, 2014-02-01)
      The 3.5 Ga Bon Accord Ni deposit occurs within the lowest serpentinized mafic ultramafic lavas of the Barberton Greenstone Belt (South Africa). Though now completely mined out, it comprised a suite of rare Ni-rich minerals that led to its interpretation as either an extraterrestrial body or as an oxidized fragment of Fe-Ni alloy originating from the terrestrial core. In this study, we draw on detailed petrographic observation and mineral chemical data, as well as previous work, to re-evaluate these ideas. The balance of evidence, from thin section (<1 mm) to regional (∼10s of km) scales, appears to support an alternative origin for Bon Accord, possibly as an oxidized Ni-sulfide deposit formed in association with ocean floor komatiite eruptions.
    • UK pension changes in 2015: some mathematical considerations

      Stubbs, John; Adetunji, Jacob; University of Derby (Cambridge University Press, 2016-06-14)
      This paper presents a mathematical treatment of some of the changes made to pension arrangements by the UK government in 2015. A mathematical model of a pension fund is developed based on three variables: life expectancy of pensioner, interest rates on investments and rates of inflation. The model enables a prospective pensioner to decide, at point of retirement and on the basis of predicted income streams, whether to opt for, (i) a (life) annuity or a draw down scheme, (ii) an inflation proofed (index linked) income or a fixed income and (iii) an immediate income or a deferred income. Numerical examples are provided to add clarity to the financial options available at retirement. On the basis of the numerical examples given, the paper concludes by urging caution on the part of the pensioner before taking an annuity rather than a draw down scheme, an index linked rather than a fixed income and a deferred rather than an immediate pension income. UK pension changes in 2015: some mathematical considerations.
    • Untangling the origin of ghost gear within the Maldivian archipelago and its impact on olive ridley (Lepidochelys olivacea) populations

      Stelfox, M; Bulling, M; Sweet, M; University of Derby; Olive Ridley Project, Cheshire (Inter-Research Science Center, 2019-12-12)
      There is little documentation available on the impact of abandoned, lost or discarded fishing nets (‘ghost nets’) on turtle populations. Here, we utilise data collected over a 5 year period to assess (1) if a particular net type or characteristic was identifiable as entangling more turtles and (2) if particular fishing practices (i.e. types of nets) could be managed to reduce turtle entanglement in the Maldivian archipelago. A total of 131 turtles were entangled in the 752 reported ghost nets, and olive ridley turtles Lepidochelys olivacea appeared to be the most vulnerable (making up 97% of entangled turtles). However, we estimate that the 752 nets in this study, reported over a 51 month period, could have entangled between 3400 and 12200 turtles across the Indian Ocean prior to being detected in the Maldives. Mesh size, seasonality (i.e. north east monsoon), and the presence of floats were all identified as variables significantly affecting the likelihood of turtle entanglement. The probability of entanglement increased as the mesh size increased but decreased when floats were present. Additionally, turtles were more likely to be entangled during the north east monsoon when currents flow from east to west. Cluster analysis indicated that there were at least 11 broadly assigned net types found floating in the study area, and these were dominated by trawl and gill nets. Our analyses highlight the need for a detailed database of existing gear types coupled with gear marking to improve traceability of ghost nets in the Indian Ocean.
    • Urban badger setts: characteristics, patterns of use and management implications

      Davison, John; Huck, Maren; Delahay, R. J.; Roper, Timothy J.; University of Sussex (2013-06-10)
      Damage caused by badger setts is an important source of human–carnivore conflict in urban areas of the UK, yet little is known about the spatial distribution of urban badger setts or their pattern of occupation. We compared the density, spatial distribution and size of setts in four urban and two rural study areas in the UK and assessed the applicability to urban systems of distinguishing between ‘main’ and ‘outlier’ setts. In addition, we used radio-telemetry to investigate diurnal patterns of sett use in one urban area (Brighton). It was possible to distinguish between main and outlier setts in urban environments, and local sett densities were comparable in urban and rural areas. However, urban badgers used substantially fewer setts than did a nearby rural population, and they spent a smaller proportion of days in outlier setts. Social groups with larger ranges had more setts available to them and, within groups, individuals with larger ranges used more setts. Outliers appeared to serve multiple functions, including allowing efficient and safe travel to important parts of the home range. We conclude that sett densities can be high in urban habitats, suggesting significant potential for settrelated problems to arise. The fact that urban main setts can be distinguished from outliers enables management actions to be tailored accordingly. In particular, because main setts seem to represent a particularly valuable resource to urban
    • Urban biodiversity and landscape ecology: Patterns, processes and planning

      Norton, Briony, A.; Evans, Karl L.; Warren, Philip H.; University of Sheffield (Springer, 2016-11-21)
      Effective planning for biodiversity in cities and towns is increasingly important as urban areas and their human populations grow, both to achieve conservation goals and because ecological communities support services on which humans depend. Landscape ecology provides important frameworks for understanding and conserving urban biodiversity both within cities and considering whole cities in their regional context, and has played an important role in the development of a substantial and expanding body of knowledge about urban landscapes and communities. Characteristics of the whole city including size, overall amount of green space, age and regional context are important considerations for understanding and planning for biotic assemblages at the scale of entire cities, but have received relatively little research attention. Studies of biodiversity within cities are more abundant and show that longstanding principles regarding how patch size, configuration and composition influence biodiversity apply to urban areas as they do in other habitats. However, the fine spatial scales at which urban areas are fragmented and the altered temporal dynamics compared to non-urban areas indicate a need to apply hierarchical multi-scalar landscape ecology models to urban environments. Transferring results from landscape-scale urban biodiversity research into planning remains challenging, not least because of the requirements for urban green space to provide multiple functions. An increasing array of tools is available to meet this challenge and increasingly requires ecologists to work with planners to address biodiversity challenges. Biodiversity conservation and enhancement is just one strand in urban planning, but is increasingly important in a rapidly urbanising world.
    • 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.
    • 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.
    • The use of gamification in the teaching of disease epidemics and pandemics.

      Robinson, Louise; Turner, Ian J.; Sweet, Michael J.; University of Derby; Environmental Sustainability Research Centre, University of Derby, Derby, DE22 1GB, UK; Centre for Excellence in Learning and Teaching, University of Derby, Derby, DE22 1GB, UK; Environmental Sustainability Research Centre, University of Derby, Derby, DE22 1GB, UK (Oxford Academic, 2018-04-26)
      With the launch of the teaching excellence framework, teaching in higher education (HE) is under greater scrutiny than ever before. Didactic lecture delivery is still a core element of many HE programmes but there is now a greater expectation for academics to incorporate alternative approaches into their practice to increase student engagement. These approaches may include a large array of techniques from group activities, problem-based learning, practical experience and mock scenarios to newly emerging approaches such as flipped learning practices and the use of gamification. These participatory forms of learning encourage students to become more absorbed within a topic that may otherwise be seen as rather ‘dry’ and reduce students engagement with, and therefore retention of, material. Here we use participatory-based teaching approaches in microbiology as an example to illustrate to University undergraduate students the potentially devastating effects that a disease can have on a population. The ‘threat’ that diseases may pose and the manner in which they may spread and/or evolve can be challenging to communicate, especially in relation to the timescales associated with these factors in the case of an epidemic or pandemic.
    • The use of seasonally resolved temperature data to identify the cause of marine climate change

      Johnson, Andrew L. A.; Valentine, Annemarie; Leng, Melanie J.; Sloane, Hilary J.; Schöne, Bernd R.; Surge, Donna; University of Derby; University of Loughborough; British Geological Survey; University of Mainz; et al. (European Geosciences Union, 2017-04)
      On the continental shelf of the eastern USA, seasonal variation in water temperature is much lower south of Cape Hatteras than it is to the north as a result of the influence of warm currents, which raise winter temperature. High temperatures north of Cape Hatteras during the Pliocene have been attributed to greater northward penetration of warm currents in the absence of a feature analogous to Cape Hatteras. However, oxygen isotope thermometry using serial ontogenetic samples from scallops reveals a high seasonal temperature range at some horizons, suggesting that overall warming was the consequence of general climate change, with the absence of a ‘Cape Hatteras’ feature allowing greater southward penetration of cold currents, resulting in low winter temperatures at a southerly latitude. Evidence from other taxa indicates that at times seasonal variation in water temperature was quite low and that there was greater northward penetration of warm currents. This may relate to increases in vigour of the Gulf Stream. The study shows how seasonally resolved temperature data can assist identification of the driving forces of marine climate change.
    • 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.
    • Using GPS telemetry to validate least-cost modeling of gray squirrel ( Sciurus carolinensis) movement within a fragmented landscape

      Stevenson, Claire D.; Ferryman, Mark; Nevin, Owen T.; Ramsey, Andrew; Bailey, Sallie; Watts, Kevin; University of Cumbria; Forest Research UK (Wiley, 2013)
      In Britain, the population of native red squirrels Sciurus vulgaris has suffered population declines and local extinctions. Interspecific resource competition and disease spread by the invasive gray squirrel Sciurus carolinensis are the main factors behind the decline. Gray squirrels have adapted to the British landscape so efficiently that they are widely distributed. Knowledge on how gray squirrels are using the landscape matrix and being able to predict their movements will aid management. This study is the first to use global positioning system (GPS) collars on wild gray squirrels to accurately record movements and land cover use within the landscape matrix. This data were used to validate Geographical Information System (GIS) least-cost model predictions of movements and provided much needed information on gray squirrel movement pathways and network use. Buffered least-cost paths and least-cost corridors provide predictions of the most probable movements through the landscape and are seen to perform better than the more expansive least-cost networks which include all possible movements. Applying the knowledge and methodologies gained to current gray squirrel expansion areas, such as Scotland and in Italy, will aid in the prediction of potential movement areas and therefore management of the invasive gray squirrel. The methodologies presented in this study could potentially be used in any landscape and on numerous species.
    • Using model systems to address the biodiversity-ecosystem functioning process

      Bulling, Mark T.; White, Piran C. L.; Raffaelli, D.; Pierce, Graham J. (2013-06-11)
      Declines in biodiversity resulting from anthropogenic disturbance to ecosystems have focused attention on the role of biodiversity in ecosystem functioning. However, the high level of complexity of ecosystems has made this a difficult topic to investigate. Much simpler model systems incorporating small-scale, spatially delimited, artificial assemblages of species have been widely used recently to address the link between biodiversity and ecosystem functioning (BEF). Their simplicity lends tractability to these systems, but has also resulted in much criticism in the literature over their relevance. Here, we examine the strengths and limitations of model systems and examine how useful these systems might be in addressing several issues that are likely to represent future challenges to understanding BEF: spatial scale, multiple trophic levels, variation, environmental stochasticity and the choice of representative combinations of species. We find that model systems have already played an important role in enhancing our understanding of BEF and are likely to continue this role in the future. However, they do have important limitations, and it is essential to take these into account when putting results into the broader context of ecosystems and to improve the level of integration of results with those from other methodologies.