James M. Gibbons

Cattle feed or bioenergy? Consequential life cycle assessment of biogas feedstock options on dairy farms.

On‐farm anaerobic digestion (AD) of wastes and crops can potentially avoid greenhouse gas (GHG) emissions, but incurs extensive environmental effects via carbon and nitrogen cycles and substitution of multiple processes within and outside farm system boundaries. Farm models were combined with consequential life cycle assessment (CLCA) to assess plausible biogas and miscanthus heating pellet scenarios on dairy farms. On the large dairy farm, the introduction of slurry‐only AD led to reductions in global warming potential (GWP) and resource depletion burdens of 14% and 67%, respectively, but eutrophication and acidification burden increases of 9% and 10%, respectively, assuming open tank digestate storage. Marginal GWP burdens per Mg dry matter (DM) feedstock codigested with slurry ranged from –637 kg CO2e for food waste to +509 kg CO2e for maize. Codigestion of grass and maize led to increased imports of concentrate feed to the farm, negating the GWP benefits of grid electricity substitution. Attributing grass‐to‐arable land use change (LUC) to marginal wheat feed production led to net GWP burdens exceeding 900 kg CO2e Mg−1 maize DM codigested. Converting the medium‐sized dairy farm to a beef‐plus‐AD farm led to a minor reduction in GWP when grass‐to‐arable LUC was excluded, but a 38% GWP increase when such LUC was attributed to marginal maize and wheat feed required for intensive compensatory milk production. If marginal animal feed is derived from soybeans cultivated on recently converted cropland in South America, the net GWP burden increases to 4099 kg CO2e Mg−1 maize DM codigested – equivalent to 55 Mg CO2e yr−1 per hectare used for AD‐maize cultivation. We conclude that AD of slurry and food waste on dairy farms is an effective GHG mitigation option, but that the quantity of codigested crops should be strictly limited to avoid potentially large international carbon leakage via animal feed displacement.

Impacts of changing relative prices on farm level dairy production in the UK

Abstract This paper presents a linear programming model designed to evaluate the impact of changes in milk to milk-quota-leasing price ratios, nitrogen fertiliser and concentrate prices on the profitability of a technically efficient UK dairy farm. The model incorporates energy and protein requirements of cows of different yield levels and allows substitution between forage and concentrate feeds. The results show that there is a large financial incentive to reduce input levels and move to lower yielding cows as milk to milk-quota-leasing price ratios fall relative to prices for concentrates and nitrogen fertiliser. However, under proposed reforms to the Common Agricultural Policy, and at current UK milk prices, technically efficient producers will find it profitable to continue feeding relatively large amounts of concentrates to relatively high yielding cows.

Consequential life cycle assessment of biogas, biofuel and biomass energy options within an arable crop rotation

Feed in tariffs (FiTs) and renewable heat incentives (RHIs) are driving a rapid expansion in anaerobic digestion (AD) coupled with combined heat and power (CHP) plants in the UK. Farm models were combined with consequential life cycle assessment (CLCA) to assess the net environmental balance of representative biogas, biofuel and biomass scenarios on a large arable farm, capturing crop rotation and digestate nutrient cycling effects. All bioenergy options led to avoided fossil resource depletion. Global warming potential (GWP) balances ranged from −1732 kg CO2e Mg−1 dry matter (DM) for pig slurry AD feedstock after accounting for avoided slurry storage to +2251 kg CO2e Mg−1 DM for oilseed rape biodiesel feedstock after attributing indirect land use change (iLUC) to displaced food production. Maize monoculture for AD led to net GWP increases via iLUC, but optimized integration of maize into an arable rotation resulted in negligible food crop displacement and iLUC. However, even under best‐case assumptions such as full use of heat output from AD‐CHP, crop–biogas achieved low GWP reductions per hectare compared with Miscanthus heating pellets under default estimates of iLUC. Ecosystem services (ES) assessment highlighted soil and water quality risks for maize cultivation. All bioenergy crop options led to net increases in eutrophication after displaced food production was accounted for. The environmental balance of AD is sensitive to design and management factors such as digestate storage and application techniques, which are not well regulated in the UK. Currently, FiT payments are not dependent on compliance with sustainability criteria. We conclude that CLCA and ES effects should be integrated into sustainability criteria for FiTs and RHIs, to direct public money towards resource‐efficient renewable energy options that achieve genuine climate protection without degrading soil, air or water quality.

Why are some biodiversity policies implemented and others ignored? Lessons from the uptake of the Global Strategy for Plant Conservation by botanic gardens

International agreements and policies play an increasingly prominent role in strategies to combat biodiversity loss. However, conservation policies can only have a conservation impact if implemented. Identifying factors determining the influence of a policy on institutions could improve the process of policy development and communication. We examine how and why botanic gardens have responded to the first phase of a global conservation policy (the Global Strategy for Plant Conservation GSPC) using quantitative (questionnaires completed by 255 botanic gardens in 67 countries) and qualitative (in-depth interviews with five gardens in five countries) methods. We found that while the majority of gardens were aware of the GSPC, older gardens in the global north, and younger global south gardens are most influenced by the GSPC. Gardens that are members of a global botanic garden network and gardens with larger budgets are implementing more targets. Targets implemented tend to be aligned with existing institutional aims. Gardens highlighted an absence of a mechanism to feedback successes and failures. The GSPC has recently been reviewed and new targets for the period of 2011–2020 developed. To widen the influence of the GSPC, dissemination should include guidelines on how institutions could implement the policy, with particular focus on influencing younger global north gardens and older global south gardens. There are plans to develop a toolkit to help gardens better understand and implement the GSPC. We recommend the toolkit include a system for GSPC implementers to communicate with each other and to feedback to policy formulators.

Training Programmes Can Change Behaviour and Encourage the Cultivation of Over-Harvested Plant Species

Cultivation of wild-harvested plant species has been proposed as a way of reducing over-exploitation of wild populations but lack of technical knowledge is thought to be a barrier preventing people from cultivating a new species. Training programmes are therefore used to increase technical knowledge to encourage people to adopt cultivation. We assessed the impact of a training programme aiming to encourage cultivation of xaté (Chamaedorea ernesti-augusti), an over-harvested palm from Central America. Five years after the training programme ended, we surveyed untrained and trained individuals focusing on four potential predictors of behaviour: technical knowledge, attitudes (what individuals think about a behaviour), subjective norms (what individuals perceive others to think of a behaviour) and perceived behavioural control (self assessment of whether individuals can enact the behaviour successfully). Whilst accounting for socioeconomic variables, we investigate the influence of training upon these behavioural predictors and examine the factors that determine whether people adopt cultivation of a novel species. Those who had been trained had higher levels of technical knowledge about xaté cultivation and higher belief in their ability to cultivate it while training was not associated with differences in attitudes or subjective norms. Technical knowledge and perceived behavioural control (along with socio-economic variables such as forest ownership and age) were predictors of whether individuals cultivate xaté. We suggest that training programmes can have a long lasting effect on individuals and can change behaviour. However, in many situations other barriers to cultivation, such as access to seeds or appropriate markets, will need to be addressed.

Chapter Two Good Modelling Practice

Abstract Models have become indispensable in environmental assessment, planning and management. However as models have increasingly been developed and disseminated, the risk of their misuse or misunderstanding of their capabilities has increased. Whether a model is used for simulation, prediction, decision making or communication of scientific analyses, it is important that its development and application conform to protocols or standards that help to maximise the scientific soundness, utility and defensibility of models and their outputs. The complexity and uncertainty inherent in environmental assessment make the pursuit of good modelling practice especially important, in spite of limited time and resources. This paper is an attempt to identify the key components of best modelling practice and our collective progress in its achievement, taking into account previous relevant reviews undertaken by several authors and agencies. The details are always likely to be the subject of lively debate, but the general components of ‘good modelling practice’ are probably not controversial. They are clear purpose, adequate reporting, and serious evaluation. Although these are common strands in the various definitions of good modelling practice the emphasis varies between different types of model application. For this reason it is important that good practice should not become overly prescriptive. We report a preliminary analysis which suggests that progress towards improving modelling practice is slow. This is despite very widespread agreement on what constitutes good practice. Why is this so? In the research community at least, the drivers for model development and evaluation are funding and publication. If modelling practice needs to be improved, and we think it does, sponsors and journals need to take a lead in creating an environment where developing a model requires that the work be undertaken under some system of good modelling practice. The suggestion has been made of a ‘good practice check list’ in the journal, Environmental Modelling and Software. While such a system would need to be flexibly applied, the principle is sound, and such steps should move us forward.

To See or Not to See: Investigating Detectability of Ganges River Dolphins Using a Combined Visual-Acoustic Survey

Detection of animals during visual surveys is rarely perfect or constant, and failure to account for imperfect detectability affects the accuracy of abundance estimates. Freshwater cetaceans are among the most threatened group of mammals, and visual surveys are a commonly employed method for estimating population size despite concerns over imperfect and unquantified detectability. We used a combined visual-acoustic survey to estimate detectability of Ganges River dolphins (Platanista gangetica gangetica) in four waterways of southern Bangladesh. The combined visual-acoustic survey resulted in consistently higher detectability than a single observer-team visual survey, thereby improving power to detect trends. Visual detectability was particularly low for dolphins close to meanders where these habitat features temporarily block the view of the preceding river surface. This systematic bias in detectability during visual-only surveys may lead researchers to underestimate the importance of heavily meandering river reaches. Although the benefits of acoustic surveys are increasingly recognised for marine cetaceans, they have not been widely used for monitoring abundance of freshwater cetaceans due to perceived costs and technical skill requirements. We show that acoustic surveys are in fact a relatively cost-effective approach for surveying freshwater cetaceans, once it is acknowledged that methods that do not account for imperfect detectability are of limited value for monitoring.

Botanic gardens can positively influence visitors’ environmental attitudes

Abstract Botanic gardens often highlight public education as a priority. Increasing knowledge about biodiversity conservation is a frequently stated aim of environmental education. This is often based on the assumption that increasing knowledge may generate positive environmental attitudes. We investigate the relationship between knowledge and environmental attitudes and whether visits to botanic gardens alter visitors’ ecological knowledge and environmental attitudes. We surveyed 1054 visitors at five UK botanic gardens, half of whom were interviewed on entry and half leaving. Our results suggest a strong positive relationship between knowledge and attitudes, although we are unable to disentangle cause and effect. We show botanic gardens have little influence on knowledge, however environmental attitudes are more positive amongst those leaving a botanic garden. This study presents the first quantitative evidence showing botanic gardens can positively influence visitors’ environmental attitudes. With over 300 million visitors a year globally, botanic gardens have the potential to greatly improve knowledge about, and attitudes towards plant conservation. Evaluating the influence botanic gardens may have on visitors can be useful both in demonstrating to funders the contribution they make, and to allow learning and development of approaches to maximise the benefits of environmental education schemes in botanic gardens.

Do not throw equations out with the theory bathwater

In a recent PNAS paper (1), Fawcett and Higginson analyze citation data for biological journals and conclude that overall citation rate is reduced by including equations in papers. As a serial offender in this regard, I found the paper interesting, if troubling. Here I show that an alternative analysis reveals a more complex picture and suggest an alternative explanation for the pattern.

Cultivation can increase harvesting pressure on overexploited plant populations

Captive breeding and cultivation of overharvested species is frequently proposed as a conservation strategy, yet there is little evidence under what conditions, if at all, the strategy is effective. We created a bioeconomic model to investigate the socioeconomic conditions favoring cultivation over wild harvesting and likely impacts on the wild population. We parameterize the model with the case study of illegal xaté palm (Chamaedorea ernesti-augusti) harvesting in Belize and Guatemala. We examine how changes in law enforcement, a price premium for cultivated leaf, land ownership, and alternative income might affect decisions to cultivate and the impact of cultivation on wild populations. We show that those switching to cultivation are largely not wild harvesters because of barriers such as land ownership. We also find that if harvesters do switch to cultivation, they may have a negative effect on the wild population through harvesting of material to set up plantations. We found increasing alternative income reduces harvesting pressure and suggests the provision of alternative livelihoods would more directly reduce pressure on the wild population. Although schemes to encourage cultivation seem an appealing conservation intervention, we urge caution in assuming that people will readily adopt cultivation of wild harvested species or that this would necessarily reduce impacts on wild populations.