Local competition and metapopulation processes drive long-term seagrass-epiphyte population dynamics

It is well known that ecological processes such as population regulation and natural enemy interactions potentially occur over a range of spatial scales, and there is a substantial body of literature developing theoretical understanding of the interplay between these processes. However, there are comparatively few studies quantifying the long-term effects of spatial scaling in natural ecosystems. A key challenge is that trophic complexity in real-world biological communities quickly obscures the signal from a focal process. Seagrass meadows provide an excellent opportunity in this respect: in many instances, seagrasses effectively form extensive natural monocultures, in which hypotheses about endogenous dynamics can be formulated and tested. We present amongst the longest unbroken, spatially explict time series of seagrass abundance published to date. Data include annual measures of shoot density, total above-ground abundance, and associated epiphyte cover from five Zostera marina meadows distributed around the Isles of Scilly, UK, from 1996 to 2011. We explore empirical patterns at the local and metapopulation scale using standard time series analysis and develop a simple population dynamic model, testing the hypothesis that both local and metapopulation scale feedback processes are important. We find little evidence of an interaction between scales in seagrass dynamics but that both scales contribute approximately equally to observed local epiphyte abundance. By quantifying the long-term dynamics of seagrass-epiphyte interactions we show how measures of density and extent are both important in establishing baseline information relevant to predicting responses to environmental change and developing management plans. We hope that this study complements existing mechanistic studies of physiology, genetics and productivity in seagrass, whilst highlighting the potential of seagrass as a model ecosystem. More generally, this study provides a rare opportunity to test some of the predictions of ecological theory in a natural ecosystem of global conservation and economic val

Seagrass meadows globally as a coupled social–ecological system: Implications for human wellbeing

Seagrass ecosystems are diminishing worldwide and repeated studies confirm a lack of appreciation for the value of these systems. In order to highlight their value we provide the first discussion of seagrass meadows as a coupled social–ecological system on a global scale. We consider the impact of a declining resource on people, including those for whom seagrass meadows are utilised for income generation and a source of food security through fisheries support. Case studies from across the globe are used to demonstrate the intricate relationship between seagrass meadows and people that highlight the multi-functional role of seagrasses in human wellbeing. While each case underscores unique issues, these examples simultaneously reveal social–ecological coupling that transcends cultural and geographical boundaries. We conclude that understanding seagrass meadows as a coupled social–ecological system is crucial in carving pathways for social and ecological resilience in light of current patterns of local to global environmental change

Citations, funding and influence in Energy-Policy research on Developing Economies

Energy research seeking to influence policy in low- and -middle-income countries (LMICs) is often funded by – and conceptualised by authors in - institutions from high-income countries (HICs). Research agendas and policy recommendations determined in HICs potentially yield the most influence on policymaking for LMICs. This leaves a multidimensional gap in how LMICs frame, contextualise, evidence and enact policy processes. The unique contribution of this paper is analysing the dynamics of prevalent energy research on LMICs through a multi-method approach using bibliometric, network science and regression-based techniques. An innovative data-driven framework was established using a sample of 6,636 papers from the Web of Science database, combined with journal impact data from Scimago Journal Ranking and country economic data from the World Bank. Results show the existence of a cycle of imbalances across research practices. Most papers recommending energy policy for LMICs have a first author based in a HIC, funded by a HIC institution. Total citations of articles on energy policy in LMICs increase with the GDP of the first author’s country (a 1% increase in GDP is correlated with a 0.68% increase in total citations). Funders support authors based in countries of the same income band as them, or higher. Therefore, we recommend revising research practices and HIC funding policies to place local actors and knowledge at the heart of energy policy research, enabling high-impact policymaking in LMICs

Tracking Nitrogen Source Using δ15N Reveals Human and Agricultural Drivers of Seagrass Degradation across the British Isles

Excess nutrients shift the ecological balance of coastal ecosystems, and this eutrophication is an increasing problem across the globe. Nutrient levels may be routinely measured, but monitoring rarely attempts to determine the source of these nutrients, even though bio-indicators are available. Nitrogen stable isotope analysis in biota is one such bio-indicator, but across the British Isles, this is rarely used. In this study, we provide the first quantitative evidence of the anthropogenic drivers of reduced water quality surrounding seagrass meadows throughout the British Isles using the stable nitrogen isotope δ15N. The values of δ15N ranged from 3.15 ‰ to 20.16 ‰ (Mean SD = 8.69 3.50‰), and were high within the Thames Basin suggesting a significant influx of urban sewage and livestock effluent into the system. Our study provides a rapid ‘snapshot’ indicating that many seagrass meadows in the British Isles are under anthropogenic stress given the widespread inefficiencies of current sewage treatment and farming practices. Ten of the eleven seagrass meadows sampled are within European marine protected sites. The ten sites all contained seagrass contaminated by nutrients of a human and livestock waste origin leading us to question whether generic blanket protection is working for seagrasses in the UK. Infrastructure changes will be required if we are to develop strategic wastewater management plans that are effective in the long-term at protecting our designated Special Areas of Conservation. Currently, sewage pollution is a concealed issue; little information exists and is not readily accessible to members of the public

On repression, and avoiding red herrings

In this response to Otgaar et al. (in press) we point out that their concern with the notion of unconscious repression is a classic example of a red herring, as it has never been endorsed as an explanation of recovered memories. We also note that Otgaar et al. have misunderstood the purpose of our article (Brewin, Li, Ntarantana, Unsworth, & McNeilis, 2019). Its aim was to demonstrate that many of the claims made by psychologists about the public’s views on memory do not rest on sound methodology. Beliefs about repression featured as one example, but it was not our objective to establish what the public do think about repression. We welcome Otgaar et al.’s (in press) additional data but regret that they have repeated the basic error we highlighted, the reliance on a single questionnaire item to assess beliefs about highly complex topics. Nevertheless, their and our findings clearly indicate that understanding of the public’s views on repression remains extremely limited, and insufficient to meaningfully contribute to legal processes

A constraint programming approach to the hospitals/residents problem

An instance I of the Hospitals/Residents problem (HR) involves a set of residents (graduating medical students) and a set of hospitals, where each hospital has a given capacity. The residents have preferences for the hospitals, as do hospitals for residents. A solution of I is a <i>stable matching</i>, which is an assignment of residents to hospitals that respects the capacity conditions and preference lists in a precise way. In this paper we present constraint encodings for HR that give rise to important structural properties. We also present a computational study using both randomly-generated and real-world instances. We provide additional motivation for our models by indicating how side constraints can be added easily in order to solve hard variants of HR

The response of the seagrass Halodule wrightii Ascherson to environmental stressors

Seagrasses are subjected to intense levels of anthropogenic disturbance as a result of the shallow nearshore waters they inhabit. Some seagrasses are known to have dynamic growth patterns, enabling them to colonize unstable shallow environments and adapt to a range of disturbances. This can result in high levels of variability in morphological and physiological attributes. The seagrass Halodule wrightii is known to be a fast-growing pioneering species with a large geographic range. The present study examines Halodule wrightii in a region under intense anthropogenic stress in order to determine what are the main environmental drivers affecting the morphology, physiology and status of these habitats. Parameters of plant morphology, physiology and status were measured either at the meadow scale (e.g. biochemistry) or at a higher frequency shoot scale (e.g. shoot width). We assigned an impact assessment index to a series of seagrass sites over a gradient of anthropogenic disturbance and found this to be explanatory of a number of the seagrass parameters measured including epiphyte cover, stable isotope δ15N and ETRmax however, it did not clearly explain shoot density, a commonly used bioindicator of environmental stress. At the shoot scale, Principal Component Analysis identified epiphyte and leaf width to have the strongest association. At the meadow scale this was shoot density, dry weight and Ek, albeit with the most impacted sites showing highest shoot density. Stable isotope (δ15N) and leaf length were most significant in explaining the variation between sites and impact category, providing a direct link between anthropogenic sources of nutrients to seagrass meadow density

Seagrass meadows support global fisheries production

The significant role seagrass meadows play in supporting fisheries productivity and food security across the globe is not adequately reflected in the decisions made by authorities with statutory responsibility for their management. We provide a unique global analysis of three data sources to present the case for why seagrass meadows need targeted policy to recognize and protect their role in supporting fisheries production and food security. (1) Seagrass meadows provide valuable nursery habitat to over 1/5th of the world's largest 25 fisheries, including Walleye Pollock, the most landed species on the planet. (2) In complex small‐scale fisheries from around the world (poorly represented in fisheries statistics), we present evidence that many of those in proximity to seagrass are supported to a large degree by these habitats. (3) We reveal how intertidal fishing activity in seagrass is a global phenomenon, often directly supporting human livelihoods. Our study demonstrates that seagrasses should be recognized and managed to maintain and maximize their role in global fisheries production. The chasm that exists between coastal habitat conservation and fisheries management needs to be filled to maximize the chances of seagrass meadows supporting fisheries, so that they can continue to support human wellbeing