Restoration science relevant for action

Considerable advances have been made in both the science and practice of restoration over the past 2 – 3 decades, and there are many examples of effective restoration projects around the world. However, ongoing human alteration of the basic biophysical settings of our planet (including climate and species distributions and abundances) renders restoration both more urgent and more difficult. There is a race to keep abreast of changing ecologies and what these mean for restoration goals and practices.  In addition to the ecological dimensions of change, there is increasing recognition of the importance of social, ethical and value-based issues in restoration.  How, then, can the concepts and practice of restoration best adapt to these trends?  Responses to this question range from a “steady as she goes” approach through to consideration of a range of different concepts and approaches that challenge and extend existing perspectives. Evolving concepts and approaches include novel ecosystems, re-wilding, species translocations, de-extinction, genetic novelty and resilience-based approaches. The opportunities and threats associated with these and other approaches are topics of current debate.  Nevertheless, careful development of the expanding tool-kit for restoration has the potential to greatly increase the efficacy and uptake of restoration as an important element in humanity’s response to rapid global change.

Restoration outcomes vary widely, even when restoration projects are conducted using similar methods across seemingly similar sites. This variability challenges the capacity for restoration practitioners to achieve specific goals and has led some to suggest that restoration outcomes are unpredictable. Yet, it remains unclear the degree to which restoration outcomes are predictable as virtually no tests of this issue exist. We employ concepts from community assembly theory and ecological forecasting to evaluate the causes of variation among restoration projects and the degree to which outcomes are predictable. We do so using a system of prairie grasslands restored by seed sowing onto abandoned agricultural lands in the central United States. Plant communities at these sites have been structured by seed arrival (through seed sowing) and environmental conditions influenced both by management (eg, prescribed fire) and outside of management control (eg, planting year weather and edaphic conditions). These community assembly drivers have led to restored plant communities tracking different trajectories over time, evident both through the identities of species and their traits. Models to forecast restored prairie plant diversity at future time points were surprisingly accurate with knowledge of only a few site attributes that can easily collected by practitioners. Our findings illustrate the merits of applying community assembly theory to interpret variation among restoration outcomes. A remarkable degree of predictability in the outcomes of grassland restoration may be afforded through knowledge of how, when, and where restoration is practiced.

Increasingly, aiming for multifunctionality in landscapes is seen as a key way forward to reconcile ecological restoration and human use of landscapes and their ecosystem services. Restoring biodiversity to degraded landscapes offers potentially large win-win opportunities for increasing biodiversity and mitigating climate change whilst also improving local livelhoods. Thus, restoration is poised to become a linchpin tool for addressing many environmental issues simultaneously. The devil is in the detail however: what (which species and habitats?) do we restore where, and how much of it is a good target to reach for what goal? To be as successful as possible, current science policy programmes related to natural climate solutions (such as the Bonn Challenge) need to step back from the forest and include consideration of threatened and highly diverse open grassy biomes as well as forest restoration as key tools for achieving multifunctionality. In the process, trade-offs and synergies in the delivery of different ecosystem services (eg carbon storage, biodiversity, water, albedo, livestock forage) through restoration action need to be clearly assessed at larger landscapes scales. This would allow an integrated land use planning using assessments of different components of the wider landscape, with different habitats being restored (mosaic-style) to allow for true multifunctionality at the landscape scale. Otherwise we risk throwing away vast amounts of biodiversity in the name of tree planting for restoration for climate action on the ground. Biodiversity safeguards (minimum biodiversity goals) are needed to ensure that we go for the best possible biodiversity outcomes despite the socioeconomic and climate mitigation-driven demands on restoration. Including an ecological and socioeconomic consideration of biodiversity and habitat safeguards is the next step of high relevance for research and practice of restoration. 

Over the past decade, calls for “restoration of biodiversity” locally, regionally and globally, have increased. This has been driven partially by the development of nationally and internationally agreed targets to restore small and depleted populations, species and communities as identified through the IUCN Red-List process. Restoration of biodiversity that is important for human well-being also has widespread international agreement (eg CBD Achi targets; IPBES Global Assessment). Global action to restore biodiversity is therefore now high on the political agenda. However, there is often less agreement about what should be restored and how this should be achieved. And much of this comes down to identifying the reason for restoration. For example, if the aim is to restore biodiversity that is iconic yet in decline, then the focus tends to be on restoring to a baseline focused on a particular structure (assemblage, number). In comparison, if aim is to restore biodiversity that is important for water regulation, carbon sequestration etc., then the focus tends to be on restoring species that provide these functional aspects. Finally, if the aim is to restore naturally occurring disturbance regimes (eg through grazing), then the focus tends to be on restoring species that provide this process. Often there is an unstated assumption that a focus on restoration of one of these baselines (structure, function, process) will also bring about positive outcomes in the others. However, this talk will demonstrate, with examples from long-term ecological records, that restoration of one aspect often comes with important trade-offs for the others; information that is essential for current and future restoration plans.  

Ecological restoration is becoming common practice, but the field of marine restoration is decades behind on terrestrial restoration science and practice. Large-scale restoration commitments for our coastlines are in for a long haul as only 30% of marine restoration attempts are deemed successful, typically costing over 100 times more than terrestrial ecosystem restoration. Hence, the field of marine restoration ecology must quickly advance to bridge this gap and to be able to meet sky-high expectations of conservationists, policy makers and investors. Dr Govers will therefore illustrate the challenges that marine restoration is facing by presenting some examples from her own work in seagrass restoration in the Dutch Wadden Sea. This world heritage area is heavily affected by human activities such as coastline alteration and fixation, intense bottom-disturbing fisheries, gas mining and climate warming. This shared use of a relatively small coastal sea, high expectations of local communities and policy makers, and shifted baselines lead to a precarious position of restoration practice in this area. Here, Dr Govers wants to reach out to the wider restoration science community on how to formulate restoration goals and measures of success and thus manage expectations for ecosystem restoration of heavily altered coastal systems.

Professor Sutherland will make three main points. Firstly that the intensity and nature of management will depend on the scale of the problem. For many small scale conservation problems we are likely to need intensive management for the foreseeable future but with the objective of them eventually persisting within a matrix of dynamic habitats. Secondly, that the evidence base is insufficiently used in restoration plans and this leads to substantial problems. Finally, that showing the outcome of restoration programmes (typically that there is more biodiversity) often do not improve wider understanding of the most effective ways to restore populations and ecosystems. Instead we should be considering including experiments of specific interventions within the design of restoration projects.

Responding to unprecedented global forest clearing and degradation, governments and international agencies are promoting restoration across vast areas. To produce benefits, at a minimum restoration must be well designed and executed ecologically. But effective restoration also requires local people to engage and benefit from restoration, now and in the future. Despite the need for interdisciplinary research (theoretical and applied) on creating successful, lasting restoration works and policies, the field remains largely siloed between the natural and social sciences. So, what can restoration ecologists learn from the social sciences (and vice versa)? How does the literature on restoration ecology engage with social aspects critical to success (eg, governance, livelihoods, culture), and where are connections lacking? What compromises - spatial, temporal, structural - are required to integrate ecological and social elements in practice? Dr Wilson’s team: 1) conducted a literature synthesis illustrating the degree to which restoration ecology interacts with the social sciences in key fields, and 2) describes select case studies highlighting successful elements of integration. Preliminary results show that the restoration literature is expanding rapidly, but is diverging rather than converging; with greater separation between the social and natural sciences. Many ‘interdisciplinary’ studies integrate fields at the end, rather than co-designing studies. But examples from the field show that when projects are co-designed from the beginning, inevitable compromises are better integrated and long-term outcomes appear promising.  Using a systems lens, Dr Wilson presents a framework that draws together these conclusions, illustrates key relationships, and shows what meaningful integration could look like. Findings can help motivate and guide the transdisciplinary work needed for successful forest landscape restoration around the world.

In recent years, there has been a surge of interest worldwide in promoting rapid and widespread reforestation. The Bonn Challenge, for example, has set a goal of restoring 350 million hectares across the planet, roughly 3% of the global ice-free land area, by 2030. But what kind of forest will be restored—and for whom—is not at all clear. Achieving restoration success, especially in complex human-dominated landscapes and regions with high levels of poverty, will require an integrated restoration agenda that supports both ecological integrity and socio-economic development. It also requires a better understanding of trade-offs between conflicting goals, between ecosystem services, between stakeholder preferences, and understanding of how and where multiple goals can best be combined.  Drawing on examples from her research in Peru, Malawi, and Ecuador, Dr Rhemtulla will discuss the importance of, challenges to, and opportunities for aligning ecological and socio-economic outcomes to improve restoration success. 

With the global rise of agriculture, livestock husbandry, and forestry, humans have simplified ecosystems by promoting the abundance of focal species groups (seed plants, large herbivores, trees) with a particular benefit to humans. Intensification of land use can be seen as increasing success in excluding negative ecological interactions (competition, predation, herbivory, parasitism) and promoting positive interactions (mutualism, decomposition) for the focal species of production, often possible at an increasingly smaller area. While in population ecology the concept of minimum viable population size has been extensively investigated and is frequently used in conservation and restoration efforts, a related notion of a minimum viable ecosystem size is mostly lacking. Professor Olff will discuss the need for, and steps towards development of this concept, presenting its key elements through a novel food web approach. In this approach, species interactions are ranked not only along a trophic axis but also along an axis of resource quality at the base of the food web. Different species groups interacting in such a network are differentially sensitive to reductions in ecosystem size. Large, mobile species with large home ranges will be relatively sensitive while small and sedentary species (plants, soil fauna) will be relatively insensitive. For small but mobile species (birds, flying insects, often making up most of the biodiversity) the outcome is unclear, as these species often interact strongly with both sedentary and large mobile groups. Formulating a minimum viable ecosystem size for restoration efforts requires therefore a better understanding of the interplay of species along multiple axes of organisation in ecological interaction networks.

National government and local authorities have recognised the Oxford Cambridge Arc as an area of significant economic strength with the potential to become a world-leading economic area. This will require significantly more homes and substantial additional infrastructure in the Arc.The Arc is valued for its wildlife, natural places and local greenspaces. They play critical roles in providing the needs of people and businesses for clean water and air, flood regulation, healthier lifestyles and climate change adaptation. They also create attractive, resilient and productive places for people to live and work in. There is a need for a bold, strategic Arc-wide plan for the environment, natural capital and biodiversity which has the same status as the industrial, housing and transport strategies. This must ensure the protection and enhancement of the existing environment. The environment, natural capital and biodiversity should also be fully integrated within the other strategies as well as the health and wellbeing plans. To be effective this will require clear governance and accountability arrangements related to the environment in all these workstreams. A local natural capital plan is being progressed by government agencies with widespread local stakeholder engagement. It builds on a natural capital investment plan scoping project carried out by the local nature partnerships. This work identified the need for agreed methodologies for baseline assessments and for concepts such as net environmental gain. The design, implementation and policy implications of the work programmes outlined above will be discussed.  

Classical restoration theory rests on assumptions of environmental stationarity, but current rapid changes in Earth systems are compelling an evolution of the original restoration model. Species have evolved a variety of mechanisms for adapting to climatic variation over a range of time scales; however, the current pace of change may exceed the adaptive capability of many species in their current geographic distributions. Higher-order ecological disturbances, such as wildfires and insect outbreaks, compound the effects of climate stress, and often operating at time scales many times faster than even the accelerated climate velocity of the current century. Such disturbances are transient processes that can trigger significant and irreversible environmental, demographic and ecosystem change. Interactions of climate change and elevated levels of disturbance constitute the greatest challenge for restoration of terrestrial ecosystems now and many decades into the future. A consensus is emerging within the restoration field that a focus on ecological resilience, rather than strict interpretation of historical reference conditions, may be necessary to maintain and enhance the adaptive capacity of many species, communities, and ecosystems. Nonetheless, departures from historical references should be undertaken cautiously and incrementally, respecting the importance of ecological legacies, refugia, species interactions, and unexpressed genetic variation. We can decompose ecological responses to climate and disturbance by applying a scaled probability model across a spectrum from persistence and recovery to system reorganisation. These processes comprise the elements of a theorem of ecological resilience relevant to the formidable challenges in a rapidly changing world.

Drylands cover c.40% of the global land surface and face numerous urgent challenges. Biodiversity loss, climate change and land degradation combine with high population growth, limited employment opportunities, high levels of poverty and poor governance, resulting in food insecurity, lack of livelihood options and sometimes even conflict and unrest. Efforts to address these challenges are supported by the post-2015 development agenda. Sustainable Development Goal 15 ‘Life on Land’ commits to “Protect, restore and promote sustainable use of terrestrial ecosystems, sustainably manage forests, combat desertification, halt and reverse land degradation and halt biodiversity loss”. This presentation considers what SDG15 means in practice. It examines ‘what works’ in tackling problems of land degradation and desertification, with particular focus on transdisciplinary approaches to prevent and reduce degradation, as well as in restoring degraded land. It establishes the importance of systems approaches in unpacking interactions in livelihood portfolios and value chains; in traversing temporal and spatial scales, stakeholders, sectors and ways of knowing; and in sharing knowledge, learning and experience to empower. It argues that restoration science needs to move beyond integrating science with indigenous, traditional and local knowledge, to build partnerships and co-produce restoration solutions. To achieve this, scientists need to meaningfully engage with transdisciplinarity.