The time evolution of marginally trapped surfaces

In previous work we have shown the existence of a dynamical horizon or marginally trapped tube (MOTT) containing a given strictly stable marginally outer trapped surface (MOTS). In this paper we show some results on the global behavior of MOTTs assuming the null energy condition. In particular we show that MOTSs persist in the sense that every Cauchy surface in the future of a given Cauchy surface containing a MOTS also must contain a MOTS. We describe a situation where the evolving outermost MOTS must jump during the coalescence of two seperate MOTSs. We furthermore characterize the behavior of MOTSs in the case that the principal eigenvalue vanishes under a genericity assumption. This leads to a regularity result for the tube of outermost MOTSs under the genericity assumption. This tube is then smooth up to finitely many jump times. Finally we discuss the relation of MOTSs to singularities of a space-time.Comment: 21 pages. This revision corrects some typos and contains more detailed proofs than the original versio

The ecosystem approach in ecological impact assessment: Lessons learned from windfarm developments on peatlands in Scotland

The Ecosystem Approach introduced in 1994 through the Convention on Biological Diversity, together with related Ecosystem-based Management and Landscape Approaches are frequently called upon to improve ecological impact assessment. Current practice typically does not have such a systems focus and we explore the potential for explicitly adopting an Ecosystem Approach in the Environmental Impact Assessment process using wind energy development on peatland, in Scotland, as a case study. Based on a review of 21 windfarm projects (>50MW) approved by the Scottish Government we provide an overview of current practice and identify and discuss how the 12 principles of the Ecosystem Approach can help identify options for more appropriate impact assessment. These include defining functional units of analysis that reflect the spatial and temporal linkages of peatland elements through hydrological connections, rather than a focus on individual vegetation types and simple distance buffers. Our conclusions are not limited to peatland and are relevant wherever meaningful functional management units can be defined, including in marine environments. Our results also show that environmental statements for wind energy development in Scotland largely ignore ecosystem services and the people that benefit from them. As for threatened species and other biodiversity features, an Ecosystem Approach is a prerequisite to the meaningful inclusion of ecosystem services in impact assessment

Glocal woodlands – The rescaling of forest governance in Scotland

As a response to global crises of climate change and biodiversity loss, the UN has called for restoring a billion hectares of land. In recognition, both governments and the private sector have pledged to restore landscapes through planting millions of hectares of forests. Private sector investment is to play a critical role in meeting these goals, through instruments such as biodiversity offsetting, philanthropy, voluntary carbon markets, sustainability funds, and climate bonds. Such instruments allow for the value of place-based ecosystems, such as standing forests, to be circulated globally. No longer are forests horizontal (in terms of their extent on a map); they are also vertical, in terms of their entanglements with institutions, and actors, operating at various scales. An overarching emphasis on the private sector however obscures the role of state institutions in engaging these multi-scalar institutions and actors. Bringing the dimension of scale to tree planting, we examine the ways in which woodland creation, a ‘national’ policy priority for the Scottish government, brings together actors, both ‘local’ and ‘global’, in an unequal context. Our analysis uncovers that in retreating from directly creating and managing woodlands to playing a supportive regulatory role, Scottish Government's forest policies increasingly rescale forest and landscape governance to private and non-profit sectors, and to individual landowners and communities. These actors, who are differently endowed in terms of resources, participate in forestry developments on an uneven playing field. Moreover, questions around power and distribution of benefits arise as woodland expansion increasingly becomes part of green investment portfolios, environmental, social, and corporate governance (ESG) commitments, offsetting, and individual philanthropy. A relational view of scale that examines prevailing relations of power and resources in given socio-political contexts can both animate and inform current discourses and policies on tree planting for climate change mitigation.ISSN:0264-8377ISSN:1873-575

Glocal woodlands – The rescaling of forest governance in Scotland

As a response to global crises of climate change and biodiversity loss, the UN has called for restoring a billion hectares of land. In recognition, both governments and the private sector have pledged to restore landscapes through planting millions of hectares of forests. Private sector investment is to play a critical role in meeting these goals, through instruments such as biodiversity offsetting, philanthropy, voluntary carbon markets, sustainability funds, and climate bonds. Such instruments allow for the value of place-based ecosystems, such as standing forests, to be circulated globally. No longer are forests horizontal (in terms of their extent on a map); they are also vertical, in terms of their entanglements with institutions, and actors, operating at various scales. An overarching emphasis on the private sector however obscures the role of state institutions in engaging these multi-scalar institutions and actors. Bringing the dimension of scale to tree planting, we examine the ways in which woodland creation, a ‘national’ policy priority for the Scottish government, brings together actors, both ‘local’ and ‘global’, in an unequal context. Our analysis uncovers that in retreating from directly creating and managing woodlands to playing a supportive regulatory role, Scottish Government’s forest policies increasingly rescale forest and landscape governance to private and non-profit sectors, and to individual landowners and communities. These actors, who are differently endowed in terms of resources, participate in forestry developments on an uneven playing field. Moreover, questions around power and distribution of benefits arise as woodland expansion increasingly becomes part of green investment portfolios, environmental, social, and corporate governance (ESG) commitments, offsetting, and individual philanthropy. A relational view of scale that examines prevailing relations of power and resources in given socio-political contexts can both animate and inform current discourses and policies on tree planting for climate change mitigation

Multifunctionality of a peri-urban landscape: exploring the diversity of residents’ perceptions and preferences

Developing successful policies for sustainable land use requires understanding the perspectives of different actors. This study explored how residents–an often under-represented and un-organized group–vary in their valuation of ecosystem services (ES) and perception of multifunctionality in a peri-urban setting. We conducted 127 interviews in the Kromme Rijn region of the Netherlands guided by an interactive, visual canvas tool (STREAMLINE). We addressed four research questions: (1) Is there variation among residents regarding preferences for ES? (2) Which competing interests do residents see in this landscape? (3) Where are hotspots of perceived multifunctionality? and (4) Can the level of perceived multifunctionality be explained by its location on the rural–urban gradient? Our findings demonstrate that while the majority of ES are important to residents of a peri-urban landscape, there is variation in relative preference towards a subset of ES (mainly provisioning services). A typology of preferences distinguishes three groups: (A)‘I want it all’–all ES (very) important; (B)‘I want most of it’–majority of ES important; and (C)‘I want some’–several ES not important at all. The majority of competing interests identified by respondents were between biodiversity and either a provisioning or cultural service. Universal hotspots of perceived multi-functionality overlapped with the area around residential areas, whereas natural (grassland) areas and water were considered multifunctional by only a small share of respondents. These perceptions and preferences do not necessarily align with current policy and management efforts, it is advised that residents’ perceptions and values are better accounted for in landscape governance

Natural capital assessment in landscape-scale land use planning: how it works and key challenges

Policy makers, land managers and investors are increasingly interested in considering nature – and the services it provides – in decision making. It is expected that quantifying and valuing natural assets will help drive decisions that are more environmentally, economically, and socially sustainable, and help address the climate and biodiversity emergencies. Government and private sector actors are increasingly looking to better recognise this ‘natural capital’ in public and corporate policies. This is driving a thriving industry of assessment frameworks, methodologies, and tools to quantify natural capital ‘assets’ ranging from stored carbon to biodiversity. But the sheer number of approaches and the language of natural capital can be confusing. This makes it hard to know which tools may for improve decision-making. This brief introduces natural capital terminology, provides a summary of the ‘natural capital approach’, outlines its relevance to strategic, landscape scale land use planning, and introduces some of the tools being developed to support the approach