Lindsey Gillson

The current prevailing perception is that human impacts on the biological realm have been overwhelmingly negative. Here, we test this narrative by considering the consequences for aspects of floristic diversity of the ‘Black Death era’ (1300–1400 ce ), where one third of Europe's population died within half a decade. Based on evidence from 109 pollen records spanning the Common Era, we find increasing floristic diversity from 0 to ~1300 ce as human populations increased, followed by rapid and substantial diversity reductions during the famine‐ and disease‐driven human mortality events of the ‘Black Death era’. As human populations recovered following the mortality shock, diversity also recovered. Strikingly, it was landscapes characterized by cereal cultivation that generated both the overall Common Era increases and the Black Death era declines in diversity. The highest diversity levels were achieved in human‐generated, mosaic landscapes, highlighting the integral role of human action in biodiverse European landscapes.

Accounting for ecological novelty, gains and past human experiences through social–ecological–technological systems (SETS) can help society navigate accelerating global biodiversity change. Popular narratives stress escalating loss of species and ecosystems, and the potential collapse of the benefits they provide to people. In the public sphere, this can present the spectre of an uninhabitable Earth and the extinction of the human species. Research suggests that these crisis narratives can raise awareness, but are counterproductive in stimulating mitigating or adaptive action. They also omit evidence of biodiversity gains and ongoing adaptation alongside losses. Archaeological evidence also highlights the human ability to take advantage of and thrive under an extremely wide range of changing and challenging ecological conditions and the provisioning opportunities these provide. This perspective provides an evidenced counterargument to claims of civilizational collapse amid environmental change. Projections show that rather than universal ecological decline, a cosmopolitan biosphere of losses and gains will probably emerge. Distilled, these insights provoke a new research agenda, centred on how we measure, frame and imagine alternative futures so that we can systematically explore pathways and scenarios for a just and thriving humanity on a climatically and ecologically transforming Earth. This article is part of the theme issue ‘The biosphere in the Anthropocene’.

The concepts of planetary boundaries are influential in the sustainability literature and assist in delineating the ‘safe operating spaces’ beyond which critical Earth system processes could collapse. Moving away from our current trajectory towards ‘hothouse Earth’ will require knowledge of how Earth systems have varied throughout the Holocene, and whether and how far we have deviated from past ranges of variability. Such information can inform decisions about where change could be resisted, accepted or where adaptation is inevitable. The need for information on long‐term (Holocene) change provides an interface for palaeoecology and sustainability that remains underexploited. In this position paper, we explore this interface, first discussing the need for long‐term perspectives and introducing examples where palaeoecology has been used in defining safe operating spaces and constraining limits of acceptable change. We describe advances in quantitative methods for analysis of time‐series data that strengthen the contribution of palaeoecology to the concepts of planetary boundaries and safe operating spaces. We consider the importance of issues of scaling from landscape to regional and global scales in operationalising planetary boundaries concepts. We distil principles for this field of research going forward and introduce three case studies which will form the basis of research on these topics.

The Central Highlands region of Madagascar is currently dominated by open and mosaic ecosystems, and the region is targeted for afforestation projects. At present, little is known about the origin of these ecosystems and whether or not they are ancient or anthropogenically derived mosaics. This paper provides new insights into the environmental history and drivers of change in the Central Highlands of Madagascar during the last 6300 years through palaeoecological records from Lake Dangovavy. Our results suggested that open and mosaic ecosystems have been present in the landscape for at least 6000 years that is, 4 cal. ka BP before human settlement (2 cal. ka BP). Between 6.3 and 2 cal. ka BP landscapes were characterized by a mosaic ecosystem dominated by a matrix of open montane grassland and ericoid shrubland with extent forest patches, associated with seasonal variation of rainfall, and fire. A matrix of ericoid shrubland remained abundant in the landscape despite an increase of fire regime and herbivory activities between 2 and 1.1 cal. ka BP. Major changes in the vegetation were recorded during the last millennium with a shift towards a more open C ₄ -dominated grassland associated with high fire frequency and herbivory activities, most likely linked to human influence. Our findings support the notion of the natural presence of open ecosystems on the islands. These shed light on the landscape history which should be considered when setting conservation goals with a particular focus on areas targeted for tree plantations and fire bans like the Central highlands of Madagascar.

Planting trees is proposed as an important climate mitigation tool, but can be detrimental to biodiversity and livelihoods if not carefully planned and managed, with landscape history and livelihoods in mind. In Madagascar, deforestation is of concern, and a threat to forest-adapted biota. However, much of Madagascar’s landscape harbours ancient mosaic and open ecosystems that are home to unique suites of flora and fauna and provide a wide range of ecosystem services. Though guidelines for ecologically and socially responsible reforestation are emerging, the potential role of landscape history and palaeoecology has been generally underemphasised. Here, using Madagascar as a case study, we argue that forest restoration projects need a sound understanding of landscape history that includes a greater integration of palaeoecological data. This would help establish the former composition and extent of forests and also investigate the antiquity of open and mosaic ecosystems. When economic interests are strong, information from palaeoecology and environmental history can help reduce biases when identifying appropriate locations and suites of species for forestation. Furthermore, a reflective approach to landscape history can contribute to restoration projects that integrate cultural and livelihood considerations. A transdisciplinary approach that considers local needs and cultural context can facilitate the design and implementation of restoration projects that share benefits equitably. Underpinning this ambition is a more comprehensive consideration of ecosystem service benefits in a changing climate that includes accurate carbon storage calculations, as well as other ecosystem services including water provision, soil formation and erosion prevention, grazing resources, medicine and cultural components.

Editorial: Insights in plant conservation

Fynbos and afrotemperate forest exist as alternate stable states in the Cape Floristic Region of South Africa. In parts of Table Mountain National Park, afrotemperate forest has expanded in recent decades. The aim of this project was to explore the drivers of this change and distinguish whether this expansion represents a recovery of forest after previous clearance during the 18th century or is a novel expansion of forest range that resulted from policies of fire suppression in the 20th century. To determine the relationships between forest and fynbos and its key drivers, pollen, non-pollen palynomorphs, charcoal, stable isotope ratios (δ¹³C) and major and trace elements were analysed from late-Holocene sediments extracted from Orange Kloof. Pollen data show that forest cover has fluctuated over the past 3690 years. At the start of the record, under drier conditions from 1670 BCE to ~170 CE, forests contracted, and dry, asteraceous fynbos dominated the landscape. Around ~170 CE there was a shift to ericaceous fynbos as water availability increased. Weak signals of Khoekhoen pastoralists may be visible in the record around 50 CE, indicated by increased spores and charcoal. A regime shift towards increased dominance of the forest occurred ~250 CE, associated with wetter climate. Clear anthropogenic signals are associated with European settlement from 1650 CE. Reinforced by human clearance of forest, fynbos expanded during the cool conditions of the late phase of Little Ice Age (~1750–1850 CE). Forest expansion in the 20th century likely reflects fire suppression and recovery from past forest clearance. Fire needs to be managed accordingly if further expansion of forest into fynbos is to be curbed.

The transformations required to achieve the Sustainable Development Goals across the African continent demand new ways of mobilising, weaving together, and applying knowledge. Research, policymaking, planning, and action must be effectively inter-linked to address complex sustainability challenges and the different needs and interests of societal actors. Transdisciplinarity (TD) – the co-production of knowledge across disciplines and with non-academic actors – offers a promising, holistic approach to foster such transformations. Yet, despite increased application of TD over the past two decades, disciplinary and sectoral silos persist. TD is not well embedded in African academic institutions and, consequently, much SDG-related research is too narrowly framed and divorced from the action space to be effective. There is an urgent need to work collectively across disciplines and society for transformation towards more sustainable and equitable development pathways. Capacities to undertake collaborative, impactful research must be strengthened, and changes in research culture are needed to support relationship building. We explore these issues by drawing on two recent online social learning processes with researchers and practitioners working on sustainability issues and TD. In each process, we built on actors’ own experiences of TD by investigating institutional, practical, and theoretical challenges and enablers of TD. Here, we synthesise our learnings, alongside key literature, and explore avenues to better: a) promote and support TD within academic institutions across Africa; b) resource TD for sustainable partnerships, and c) strengthen TD practices and impacts to support transformation to sustainability across diverse places and contexts.