key: cord-1052842-i8dcdy8d authors: Corlett, Richard T. title: Safeguarding our future by protecting biodiversity date: 2020-05-20 journal: Plant Divers DOI: 10.1016/j.pld.2020.04.002 sha: f387ee8b2f0d83935f85d0abe5b0eba507391d79 doc_id: 1052842 cord_uid: i8dcdy8d The Anthropocene is marked by twin crises: climate change and biodiversity loss. Climate change has tended to dominate the headlines, reflecting, in part, the greater complexity of the biodiversity crisis. Biodiversity itself is a difficult concept. Land plants dominate the global biomass and terrestrial arthropods probably dominate in terms of numbers of species, but most of the Tree of Life consists of single-celled eukaryotes, bacteria, and archaea. Wild plants provide a huge variety of products and services to people, ranging from those that are species-specific, such as food, medicine, and genetic resources, to many which are partly interchangeable, such as timber and forage for domestic animals, and others which depend on the whole community, but not on individual species, such as regulation of water supply and carbon sequestration. The use of information from remote sensing has encouraged a simplified view of the values of nature’s contributions to people, but this does not match the way most people value nature. We can currently estimate the proportion of species threatened by human impacts only for a few well-assessed groups, for which it ranges from 14% (birds) to 63% (cycads). Less than 8% of land plants have been assessed, but it has been estimated that 30-44% are threatened, although there are still few (0.2%) well-documented extinctions. Priorities for improving protection of biodiversity include: improving the inventory, with surveys focused on geographical areas and taxonomic groups which are under-collected; expanding the protected area system and its representativeness; controlling overexploitation; managing invasive species; conserving threatened species ex situ; restoring degraded ecosystems; and controlling climate change. The Convention on Biological Diversity (CBD) COP15 and the United Nations Framework Convention on Climate Change (UNFCCC) COP26 meetings, both postponed to 2021, will provide an opportunity to address both crises, but success will require high ambition from all participants. The preamble to the 1992 Convention on Biological Diversity (CBD) affirms that 'that the 36 conservation of biological diversity is a common concern of humankind' and it would be hard to 37 find anyone who disagrees with this statement. Yet we continue to lose biodiversity, locally, 38 regionally, and globally. What is going on? Why is this still happening when apparently nobody 39 wants it to? One possible contributing factor is that the status of biodiversity as a universal 'good 40 thing' has meant that we have not had to think out clearly what exactly we mean by the term, 41 why we need it, what we ourselves lose when biodiversity declines, and-perhaps most 42 importantly-what we are prepared to do to protect it. Contrast the ongoing biodiversity crisis 43 with the climate crisis, where these questions are readily answerable-indeed, quantifiable-and 44 it is easy to see why it is climate change that tends to dominate the headlines and public 45 attention. The aim of this review, therefore, is first to clarify the meaning of the term biodiversity 46 and then to summarize the links between biodiversity and human wellbeing, with a focus on 47 plants, and to assess the major gaps in our current efforts to protect it. Numbers of species-the most widely used metric for biodiversity-are even less certain, 71 but mid-range estimates suggest that animals do much better using this metric, with recent 72 estimates for terrestrial arthropods of around 7 million species (Stork, 2018) , to which can be 73 added a million or so marine arthropods and all the other animals. Fungi are next in terms of 74 species richness, with an estimated 2.2-3.8 million species (Hawksworth and Lücking, 2017) . 75 Perhaps surprisingly, a recent estimate for prokaryotes, based on molecular sequence data, 76 suggests a global total of 'only' 0.8-1.6 million of what could be termed species, with this low 77 total reflecting the fact that most prokaryotes seem to be globally distributed (Louca et al., 2019) . There are still no robust estimates for the single-celled eukaryotes, while land plants include 79 around 400,000 known species (Nic Lughadha et al., 2016) , with perhaps another 50,000-80 100,000 still unknown (Corlett, 2016). All these numbers are based, more or less closely, on actual counts, but much higher 82 estimates of species richness for some groups have been obtained by less direct methods. Larsen although functional diversity-the range of things that organisms do-is difficult to compare 114 across such different groups, it is clearly low in land plants, which mostly do more or less the 115 same thing, and is exceptionally high in some protist groups. In summary, we live on a planet that is plant-dominated in terms of biomass, bacteria-117 dominated in terms of numbers and phylogenetic diversity, and, on current data, probably 118 animal-dominated in terms of species. Whether there are fewer than 10 million or more than a trillion species, an obvious 121 question is: do we need them all? It is easy to imagine a small group of humans, using near- will often be trade-offs between provisioning services, which involve harvesting wild species, 146 and other services, including regulating, cultural, and supporting services, which depend on 147 more-or-less intact ecosystems. The use of wild species as genetic resources does not fit well under 'provisioning', since 149 only genetic material is incorporated into the product that is eventually used or consumed. Wild Rare species contribute less to these so-called 'supporting services', but there is evidence that The availability of information from remote sensing, and from regional and global 195 databases, has allowed a subset of ecosystem services-or plausible proxies for them-to be On the other hand, if it is true that most microbes are globally distributed, then they will 233 certainly be less vulnerable to extinction than multicellular species with more restricted ranges. Less than 8% of land plants have been assessed, but estimates based on regional To protect biodiversity, we need to know which species are where. Around two million 248 species have been described, out of a total likely to be at least 10 million, so doing this 249 comprehensively is clearly impossible at present. The large number of species still waiting to be 250 described is known as the 'Linnean shortfall', after Carl Linnaeus, the father of modern 251 taxonomy. In practice, therefore, conservation operates on the assumption that the biodiversity 252 we know best-usually plants, birds, and mammals-can act as an indicator and 'umbrella' for 253 the protection of everything else: including most insects, nematodes, protists, archaea, and never-254 isolated bacteria. We do not know how accurate this assumption is, but it is currently the best we 255 can do. Increasing the rate of species discovery and description is therefore a key need for the on species distributions so that we can assess conservation needs and priorities. This so-called 262 'Wallacean shortfall', named after Alfred Wallace, the father of modern zoogeography, applies 263 even to the best-known groups taxonomically, although the data for birds is pretty good. New technologies can help with both the Linnean and Wallacean shortfalls, but 'boots on the 265 ground' are also essential, and the trained people and resources for this will often be the limiting Controlling climate change is too large and complex a topic to cover here in any detail. The 461 window of opportunity for preventing global warming of 1.5 o C is closing but has not yet closed, 462 and we must rapidly reduce greenhouse emissions and maximize natural sinks (IPCC, 2018). We 463 also need to minimize the impacts of climate change on biodiversity, as we have already had 1 o C 464 of global warming, along with increasing temperature and rainfall extremes, and further warming 465 is inevitable under even the most optimistic scenarios. It may be possible to reduce the impacts 466 in the medium term by minimizing other stresses on wild species, but we also need to provide 467 connectivity across environmental gradients, so species can move to more favorable climates. 468 However, the many edaphic specialists-both plants and animals-may be unable to move 469 (Corlett and Tomlinson, 2020) and many other species will not move fast enough to track 470 favorable conditions (Corlett and Westcott, 2013). Assisted migration may be an option for some 471 of these species, but this needs a lot more research. However, many Aichi targets will certainly not be attained by the 2020 deadline and 487 achievement of the Paris targets is looking increasingly challenging. In preparation for COP26, each country is expected to update and strengthen the 523 commitments to combatting climate change made at the time of the Paris agreement in their 524 'nationally determined contributions' (NDCs). As recognized at the time, these initial 525 commitments were insufficient to meet the goals agreed in Paris in 2015, so the first revision is 526 extremely important. Each country's revision needs to set it on a path to carbon neutrality-net 527 zero emissions-by 2050, or soon after. Most of the initial NDCs focused on power generation 528 and forests, but net zero emissions will also require massive changes in transport, industry, and 529 agriculture. Non-state actors-cities, businesses, investors-must be part of this, setting targets 530 compatible with national and global goals. International aviation and shipping will have to be 531 included, for the first time. COP15 and COP26 are not independent events, since the same countries will be 533 involved, and nature-based contributions to climate-change mitigation will feature in both. Both 534 require high ambition if they are to be successful, and both will require leadership from China, as 535 the host country in Kunming and as the largest current contributor to global greenhouse gas 536 emissions in Glasgow. One lesson we have all learned from the COVID-19 pandemic is that 537 nature does better without us. All over the world, there were unprecedented declines in air 538 pollution, while wildlife reappeared in areas from which it had been absent for decades. For a 539 few months, we could clearly see some of the damage we have done, and we will continue to do 540 unless we make drastic changes. In 2021, we have an opportunity to set the world on a new 541 course. Let us use it wisely. Species richness alone does not predict 597 cultural ecosystem service value Tetrapods on the EDGE: Overcoming 599 data limitations to identify phylogenetic conservation priorities Fungal diversity revisited: 2.2 to 3.8 million species The evidence for human agency in the Late Pleistocene megafaunal 603 extinctions Digitization and the future of natural history collections Terrestrial fluxes of carbon in GCP carbon budgets 610 A new view of the tree of life Global dataset shows geography and life form predict modern plant extinction and 613 rediscovery Global warming of 1.5°C. An IPCC Special Report on the impacts of global 618 warming of 1.5°C above pre-industrial levels Botanical drugs in Ayurveda and traditional Chinese 621 medicine Essential biodiversity variables for mapping and monitoring species populations Inordinate fondness multiplied and 626 redistributed: the number of species on Earth and the new pie of life Survey completeness of a global citizen-science database of 629 bird occurrence A comparison of eDNA to camera trapping for 631 assessment of terrestrial mammal diversity Effect of terrestrial vegetation growth on climate 636 change in China Scaling laws predict global microbial diversity Conservation of freshwater bivalves at the global scale: diversity, threats, and research need A census-based estimate of Earth's 643 bacterial and archaeal diversity The biomass and biodiversity of the continental subsurface Restoration priorities to achieve the global protected area target Rare species support vulnerable functions in high-diversity ecosystems Counting counts: revised estimates of numbers of accepted species of flowering plants, seed 654 plants, vascular plants and land plants with a review of other recent estimates Improvements in 657 ecosystem services from investments in natural capital Global conservation of phylogenetic 659 diversity captures more than just functional diversity Nitrogen 661 deposition and plant biodiversity: past, present, and future Cryobiotechnologies: Tools for expanding ex situ conservation to all plant species Ethnomedical plant diversity in Thailand Mass 668 extinction in poorly known taxa Forest foods and healthy 670 diets: Quantifying the contributions Past, present, and future perspectives of 672 environmental DNA (eDNA) metabarcoding: A systematic review in methods, monitoring, 673 and applications of global eDNA Protecting 675 half of the planet could directly affect over one billion people Creating a sustainable food 677 future Grounding nature-based 679 climate solutions in sound biodiversity science Understanding the value and limits of nature-based solutions to 2 climate change and other 682 global challenges An overview of recent progress in the implementation 684 of the Global Strategy for Plant Conservation -a global perspective To name those lost: assessing 687 extinction likelihood in the Australian vascular flora When do more species maximize 689 more ecosystem services? The impact of genetic 691 changes during crop domestication The trajectory of the 693 Anthropocene: The Great Acceleration A third of the tropical African flora is potentially threatened with extinction How many species of insects and other terrestrial arthropods are there on 698 earth? Explanations for the quality of biodiversity inputs to 701 Environmental Impact Assessment (EIA) in areas with high biodiversity value 262 Voyages beneath the sea: a global assessment of macro-and 706 megafaunal biodiversity and research effort at deep-sea hydrothermal vents A global 1km consensus land cover product for biodiversity and 708 ecosystem modeling Comment on "The global tree restoration potential Asian Sacred Natural Sites: Philosophy and Practice in 712 Protected Areas and Conservation Set a global target for ecosystems Global 718 impacts of future cropland expansion and intensification on agricultural markets and 719 biodiversity Progress toward equitably managed protected areas in Aichi Target 721 11: A global survey I have had useful discussions on many of the issues covered here with Jin Chen, David 545 Dudgeon, Keping Ma, Richard Primack, Kyle Tomlinson, and many others.