73 research outputs found

    The effects of the changing energy situation on demand for industrial heat exchangers

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    The Project arose during a period in which the World was still coming to terms with the effects and implications of the so called 'energy crisis' of 1973/74. Serck Heat Transfer is a manufacturer of heat exchangers which transfer heat between fluids of various sorts. As such the company felt that past and possible future changes in the energy situation could have an impact upon the demand for its products. The thesis represents the first attempt to examine the impact of changes in the energy situation (a major economic variable) on the long term demand for heat exchangers. The scope of the work was limited to the United Kingdom, this being the largest single market for Serek's products. The thesis analyses industrial heat exchanger markets and identifies those trends which are related to both the changing energy situation and the usage of heat exchangers. These trends have been interpreted In terms of projected values of heat exchanger demand. The projections cover the period 197S to the year 2000. Also examined in the thesis is the future energy situation both internationally and nationally and it is found that in the long term there will be increasing pressure on consumers to conserve energy through rising real prices. The possibility of a connection between energy consumption and heat exchanger demand is investigated and no significant correlation found. This appears to be because there are a number of determinants of demand besides energy related factors and also there is a wide diversity of individual markets for heat exchangers. Conclusions are that in all markets, bar one, the changing energy situation should lead to a higher level of heat exchanger demand than would otherwise be the case had the energy situation not changed. It is also pointed out that it is misleading to look at changes in one influence on the demand for a product and ignore others

    What evidence exists on the impacts of large herbivores on climate change? A systematic map protocol

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    Background- In recent years there has been an increased focus on the role of large herbivores in ecosystem restoration and climate change mitigation. There are multiple processes by which large herbivores could potentially influence climate feedback and forcing effects, but the evidence has not yet been synthesised in a systematic and accessible format. Grazing, browsing, trampling, defecation, and seed dispersal by large herbivores can influence vegetation and soils in ways that may directly or indirectly contribute to climate change or mitigation. For example, changes in vegetation could impact wildfire regimes, carbon storage, and albedo, with ultimate impacts on climate. These processes may be influenced by herbivore species composition, density, and functional traits. The main aim of this systematic map is to synthesise the range of research on climate feedback and forcing effects from large herbivores (≄ 10 kg) in terrestrial ecosystems. We also aim to identify knowledge clusters and gaps in the research base, as well as assessing the potential for quantitative analyses. Methods- A search of peer-reviewed and grey literature will be conducted using a range of bibliographic databases, search engines and websites. The search strategy will involve using a pre-defined search string with Boolean operators. All search results will be screened for relevance according to specific eligibility criteria. Screening will be conducted in two stages: all articles will initially be screened by title and abstract, then those that meet the eligibility criteria will be screened by full text. At both stages, articles will be excluded if they don’t meet all eligibility criteria or if they meet any exclusion criteria. All articles included as eligible after full text screening will be coded. At each stage (of screening and coding) a proportion of articles will be processed independently by two reviewers to assess inter-reviewer reliability and resolve differences. The evidence will be presented in a searchable database with accompanying visual outputs. A narrative synthesis will be provided outlining the range and distribution of evidence, knowledge gaps and clusters, potential bias, and areas for further research

    Functional traits of the world’s late Quaternary large-bodied avian and mammalian herbivores

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    Prehistoric and recent extinctions of large-bodied terrestrial herbivores had significant and lasting impacts on Earth’s ecosystems due to the loss of their distinct trait combinations. The world’s surviving large-bodied avian and mammalian herbivores remain among the most threatened taxa. As such, a greater understanding of the ecological impacts of large herbivore losses is increasingly important. However, comprehensive and ecologically-relevant trait datasets for extinct and extant herbivores are lacking. Here, we present HerbiTraits, a comprehensive functional trait dataset for all late Quaternary terrestrial avian and mammalian herbivores ≄10 kg (545 species). HerbiTraits includes key traits that influence how herbivores interact with ecosystems, namely body mass, diet, fermentation type, habitat use, and limb morphology. Trait data were compiled from 557 sources and comprise the best available knowledge on late Quaternary large-bodied herbivores. HerbiTraits provides a tool for the analysis of herbivore functional diversity both past and present and its effects on Earth’s ecosystems

    Science for a wilder Anthropocene: synthesis and future directions for trophic rewilding research

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    Trophic rewilding is an ecological restoration strategy that uses species introductions to restore top-down trophic interactions and associated trophic cascades to promote self-regulating biodiverse ecosystems. Given the importance of large animals in trophic cascades and their widespread losses and resulting trophic downgrading, it often focuses on restoring functional megafaunas. Trophic rewilding is increasingly being implemented for conservation, but remains controversial. Here, we provide a synthesis of its current scientific basis, highlighting trophic cascades as the key conceptual framework, discussing the main lessons learned from ongoing rewilding projects, systematically reviewing the current literature, and highlighting unintentional rewilding and spontaneous wildlife comebacks as underused sources of information. Together, these lines of evidence show that trophic cascades may be restored via species reintroductions and ecological replacements. It is clear, however, that megafauna effects may be affected by poorly understood trophic complexity effects and interactions with landscape settings, human activities, and other factors. Unfortunately, empirical research on trophic rewilding is still rare, fragmented, and geographically biased, with the literature dominated by essays and opinion pieces. We highlight the need for applied programs to include hypothesis testing and science-based monitoring, and outline priorities for future research, notably assessing the role of trophic complexity, interplay with landscape settings, land use, and climate change, as well as developing the global scope for rewilding and tools to optimize benefits and reduce human–wildlife conflicts. Finally, we recommend developing a decision framework for species selection, building on functional and phylogenetic information and with attention to the potential contribution from synthetic biology

    A critical perspective on the concept of biocultural diversity and its emerging role in nature and heritage conservation

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    The continuing losses of biodiversity around the world remain problematic for nature conservation. A fundamental issue that has triggered debates in nature conservation is the relationship between human culture, heritage and history, and nature expressed as ecology or biodiversity. Traditionally, nature conservation has been pursued separately from aspects of cultural heritage; a situation which seems perplexing when we consider the importance of traditional management in the maintenance of biodiversity in many areas now “protected” for nature. To address these broad issues, fundamental to future landscape sustainability, we need to have clear definitions of concepts and terms. This paper considers the historical development of the key concepts that frame biocultural diversity and the paradigms relating to biocultural assets or eco-cultural landscapes. This is pertinent to both researchers and to practitioners or policymakers, and we suggest ways biocultural diversity can improve global conservation efforts

    Rewilding complex ecosystems

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    BACKGROUND: Rapid global change is creating fundamental challenges for the persistence of natural ecosystems and their biodiversity. Conservation efforts aimed at the protection of landscapes have had mixed success, and there is an increasing awareness that the long-term protection of biodiversity requires inclusion of flexible restoration along with protection. Rewilding is one such approach that has been both promoted and criticized in recent years. Proponents emphasize the potential of rewilding to tap opportunities for restoration while creating benefits for both ecosystems and societies. Critics discuss the lack of a consistent definition of rewilding and insufficient knowledge about its potential outcomes. Other criticisms arise from the mistaken notion that rewilding actions are planned without considering societal acceptability and benefits. Here, we present a framework for rewilding actions that can serve as a guideline for researchers and managers. The framework is applicable to a variety of rewilding approaches, ranging from passive to trophic rewilding, and aims to promote beneficial interactions between society and nature. ADVANCES: The concept of rewilding has evolved from its initial emphasis on protecting large, connected areas for large carnivore conservation to a process-oriented, dynamic approach. On the basis of concepts from resilience and complexity theory of social-ecological systems, we identify trophic complexity, stochastic disturbances, and dispersal as three critical components of natural ecosystem dynamics. We propose that the restoration of these processes, and their interactions, can lead to increased self-sustainability of ecosystems and should be at the core of rewilding actions. Building on these concepts, we develop a framework to design and evaluate rewilding plans. Alongside ecological restoration goals, our framework emphasizes people’s perceptions and experiences of wildness and the regulating and material contributions from restoring nature. These societal aspects are important outcomes and may be critical factors for the success of rewilding initiatives (see the figure). We further identify current societal constraints on rewilding and suggest actions to mitigate them. OUTLOOK: The concept of rewilding challenges us to rethink the way we manage nature and to broaden our vision about how nature will respond to changes that society brings, both intentionally and unintentionally. The effects of rewilding actions will be specific to each ecosystem, and thus a deep understanding of the processes that shape ecosystems is critical to anticipate these effects and to take appropriate management actions. In addition, the decision of whether a rewilding approach is desirable should consider stakeholders’ needs and expectations. To this end, structured restoration planning—based on participatory processes involving researchers, managers, and stakeholders—that includes monitoring and adaptive management can be used. With the recent designation of 2021–2030 as the “decade of ecosystem restoration” by the United Nations General Assembly, policy- and decision-makers could push rewilding topics to the forefront of discussions about how to reach post-2020 biodiversity goals

    Saving the world’s terrestrial megafauna

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    From the late Pleistocene to the Holocene, and now the so called Anthropocene, humans have been driving an ongoing series of species declines and extinctions (Dirzo et al. 2014). Large-bodied mammals are typically at a higher risk of extinction than smaller ones (Cardillo et al. 2005). However, in some circumstances terrestrial megafauna populations have been able to recover some of their lost numbers due to strong conservation and political commitment, and human cultural changes (Chapron et al. 2014). Indeed many would be in considerably worse predicaments in the absence of conservation action (Hoffmann et al. 2015). Nevertheless, most mammalian megafauna face dramatic range contractions and population declines. In fact, 59% of the world’s largest carnivores (≄ 15 kg, n = 27) and 60% of the world’s largest herbivores (≄ 100 kg, n = 74) are classified as threatened with extinction on the International Union for the Conservation of Nature (IUCN) Red List (supplemental table S1 and S2). This situation is particularly dire in sub-Saharan Africa and Southeast Asia, home to the greatest diversity of extant megafauna (figure 1). Species at risk of extinction include some of the world’s most iconic animals—such as gorillas, rhinos, and big cats (figure 2 top row)—and, unfortunately, they are vanishing just as science is discovering their essential ecological roles (Estes et al. 2011). Here, our objectives are to raise awareness of how these megafauna are imperiled (species in supplemental table S1 and S2) and to stimulate broad interest in developing specific recommendations and concerted action to conserve them

    Everything under control? Comparing Knepp Estate rewilding project with ‘traditional’ nature conservation

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    ‘Rewilding’ is an increasingly prominent concept in conservation, but one that has attracted controversy. Debate frequently focuses on human ‘control’ over nature. ‘Traditional’ conservation has been presented as involving ‘high control,’ and rewilding as ‘low control.’ Opposition to rewilding often stems from a perceived lack of control and associated perception of increased risk and uncertainty. This paper explores the concept of control in conservation. I identify multiple dimensions of control (‘stabilisation’, ‘location’, ‘prediction’ and ‘outputs’), illustrating that control is not a simple, linear concept. I compare two ethnographic case studies: the Sussex Wildlife Trust’s Old Lodge nature reserve; and Knepp Estate, one of the most influential rewilding projects in the UK. I use them to test assertions made about control in ‘traditional’ conservation and ‘rewilding’. I outline how Old Lodge does not exert precise control in all respects, but involves elements of uncertainty and negotiation. I describe how Knepp’s model of rewilding reduces control in some dimensions but potentially increases it in others. I conclude that, while Knepp’s rewilding does represent a significant conceptual departure from ‘traditional’ conservation, it should not be characterised as an approach that reduces control in a simplistic way. Based on this analysis, I argue that reduction of control does not necessarily underpin the concept of rewilding. Rather, there is interplay between different control dimensions that combine to form multiple ‘configurations of control.’ Using a framework of ‘configurations of control’, debate about the place of rewilding in conservation can become less polarised, and instead involve an active discussion of what configuration of control is desired. This analysis has the potential to increase understanding of rewilding projects as part of plural conservation strategies, in the UK and globally

    Rewilding as a restoration strategy for lowland agricultural landscapes: Stakeholder-assisted multi-criteria analysis in Dorset, UK

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    © 2018 Elsevier GmbH The ongoing loss of global biodiversity suggests that established conservation practices have not been fully successful at halting species decline. Rewilding, a restoration strategy focused on restoring ecological processes, has become increasingly prominent as a potential means of addressing this problem. Rewilding has been described as a versatile approach that is applicable even in areas with dense human populations and productive agricultural landscapes such as the lowlands of Western Europe. Yet little is known about the options that might exist for rewilding such landscapes, or about their relative suitability. The present study addresses this knowledge gap by assessing the relative popularity and suitability of different rewilding scenarios in the county of Dorset, south-west England, involving the consultation of local stakeholders. Survey results showed strong support for rewilding among stakeholders, with the reintroduction of beavers (Castor fiber) and pine martens (Martes martes) being especially popular. Yet stakeholder perceptions also differed regarding how rewilding should be defined, and what it comprises. The suitability of the proposed rewilding approaches was measured through a spatial multi-criteria analysis using the following variables: popularity among stakeholders, suitability within relevant land cover types, and suitability at the landscape-scale. Naturalistic grazing and farmland abandonment emerged as the most suitable rewilding options overall, although these were not the most popular choices. Overall, these results suggest that land managers in lowland agricultural landscapes could consider rewilding as one of the land management options available to them, provided that the options being considered are ecologically appropriate and local stakeholders have been consulted. In the UK, such rewilding options might be supported by new national agricultural land use policies currently under development. In areas of continental Europe where agricultural land abandonment is more widespread, policy-makers seeking to address the issue could look towards the EU's wilderness guidelines for potential solutions that promote rewilding while offsetting the costs incurred by local stakeholders. In either context, integrated exploration of stakeholder values and ecological data as presented here can potentially be used to evaluate the relative suitability and popularity of different rewilding approaches, and thereby establish priorities
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