How much biodiversity can we lose before it starts impacting our quality of life? We all depend on well-functioning ecosystems, whether we are aware of this or not. Yet measuring how much biodiversity we are losing across the African continent, and what that means for our well-being, is a difficult task. To address this challenge, we are mobilising hundreds of African biodiversity experts to produce a continental map of ‘biodiversity intactness’ that is credible and useful to African decision-makers.
Biodiversity and human well-being
Biodiversity is fundamental to human well-being. A recent assessment of the Intergovernmental Science Policy Panel on Biodiversity and Ecosystem Services (IPBES) found that biodiversity and its contributions to people in Africa are ‘essential to providing for the continent’s food, water, energy, health and secure livelihoods’. The report highlights biodiversity as ‘a strategic asset for sustainable development and achievement of the 2030 Sustainable Development Goals’.¹
Hundreds of millions of people across Africa depend on biodiversity directly for their livelihoods, particularly in rural areas. Urban dwellers also rely on biodiversity, though often more indirectly. In Southern Africa, for example, the miombo and mopane woodlands are the dominant ecosystems. These landscapes provide services that support the livelihoods of 100 million people in rural areas, and 50 million people in cities². Wild fruit, vegetables, honey and bushmeat are vital for nutrition and medicine for both rural people and nearby city dwellers. Three-quarters of the region’s energy comes from these woodlands, with charcoal providing affordable energy for urban dwellers and a flow of money to rural areas. The ecosystems also support much of the region’s agriculture, and thus food security, by creating healthy soils for farmers and conserving insect pollinators on which crops depend. By absorbing water, the woodlands mitigate floods, and they store a comparable mass of carbon to the Congo basin rainforests. Africa’s woodlands, together with its equatorial rainforests, thus provide a global service of locking up carbon in intact ecosystems – alleviating a climate change crisis that African countries did so little to cause.
Africa’s wild ecosystems have high cultural significance to the people that have occupied them for thousands of years (sacred groves, gravesites, and the dwelling places of ancestral spirits). The same wild landscapes and particularly their iconic megafauna – lions, elephants, rhinos, gorillas – also draw millions of tourists to the continent each year. Tourism provides one in 15 African jobs – 24.3 million jobs in total³. The continent’s wildlife safari industry is estimated to generate $42.9 billion each year.⁴ In several countries, wildlife tourism is a major contributor to GDP.⁵
Biodiversity and development
While people across the continent and beyond depend on and value Africa’s biodiversity and ecosystems, these things are undergoing rapid transformation and degradation. This is being driven most significantly by agricultural expansion, water abstraction, urbanisation, and the extractives sector (mining, oil, gas, forestry). The changes are taking place to meet the demands of developing the continent. Africa currently has the fastest-growing population on Earth. It rose from 290 million in 1960 to 1.35 billion in 2019 and is projected to reach 1.5 billion in 2025 and 2.4 billion in 2050.⁶ It is also the fastest urbanising region in the world, a process unprecedented in its speed and scale. By 2040, over half of all Africans will be living in urban areas.⁷ Over the coming decades, African governments will need to navigate this rapid change while simultaneously sustaining the ecosystems that provide the capital for human development.
The continent has the highest number of poor people in the world, with a majority living in rural areas and depending on farming for their livelihoods. One of the major manifestations of poverty in Africa is malnutrition, especially child stunting. For poor households, access to intact forests and their services (eg wild foods, clean water) has been found to significantly reduce child stunting, as well as anaemia, and diarrhoeal disease.⁸
We are thus faced with a seeming contradiction. The need for development and improved quality of life for Africa’s people is causing degradation of biodiversity and ecosystem services. Yet it is on these very services that human well-being depends, even as populations urbanise and become wealthier. The critical question, therefore, is how African decision-makers can navigate development in ways that conserve the biodiversity on which humanity ultimately depends.
For the continent’s ecosystems to be maintained and meet the demands of socio-economic growth, we need transformative changes in governance.⁹ We need decision-making that recognises the role of biodiversity and its services in ensuring just and sustainable development. Global biodiversity is governed by a range of multilateral environmental agreements, including the Convention on Biological Diversity (CBD). Countries agree to meet targets set by these conventions. For example, one of the 20 Aichi targets agreed by all CBD countries states that “By 2020, ecosystems that provide essential services, including services related to water, and contribute to health, livelihoods and well-being, are restored and safeguarded, taking into account the needs of women, indigenous and local communities, and the poor and vulnerable”. Through these multilateral environmental agreements and targets, the intention is that biodiversity is integrated into national and local development, poverty reduction strategies, and incorporated into national accounting.
Measuring biodiversity
Integrating biodiversity into decision-making makes sense in theory but is challenging in practice. It requires a ‘measure’ of biodiversity, for a given country or province or municipality. How does one measure biodiversity? The diversity of life present in an area gives rise to complex, dynamic ecosystems that are ‘greater than the sum of their parts’. To function properly, these ecosystems need a diverse mix of species, from top predators to micro-organisms, and they need these species in appropriate abundances. They also need certain processes, like fire and herbivory, to sustain the diversity from which services are generated. It is therefore an enormous undertaking to measure the aspects of biodiversity that really matter, for all ecosystems across the entire continent, and to identify where we see ‘too much’ biodiversity loss.
Given these challenges, the ways biodiversity is measured in practice are often very simplistic, such as the number of species that are threatened or have gone extinct. The difficulty with such measures is that species can stop contributing to a healthy ecosystem long before they are considered threatened because their numbers decline below a threshold. Similarly, countries often measure the loss of natural vegetation to agriculture, forestry, or urbanisation, as a proxy for biodiversity loss. This is a proxy we can increasingly measure from satellite imagery, making it cheap and practical. But a relatively intact piece of vegetation may be empty of important species if there is overharvesting or pollution, which can dramatically impact ecosystem functioning. We therefore need pioneering approaches to measure biodiversity across the continent, which are practical while not compromising the relevant details.
An entirely different approach to measuring biodiversity is to ask the people who work in these ecosystems for their insights on how much biodiversity remains. There is a wealth of knowledge across the continent on how biodiversity is being impacted by people. This knowledge is held by African biodiversity experts – researchers, field rangers, tour guides, museum curators – the people who work on a daily basis in changing landscapes. What we need is a way of aggregating all of this expert knowledge into a biodiversity indicator that captures how, where and why biodiversity is being lost across Africa, and how much is too much.
Expert elicitation
We are trying to quantify such an indicator. Over the past year, I have reached out to experts across broad groups of African biodiversity (e.g. plants, mammals, reptiles, etc.). These experts have then reached out to their networks of local experts and so on. The process is ongoing and we have involved over 100 experts working in 18 sub-Saharan African countries so far. We convene these experts online and ask them all to do the same thing – to estimate how different types of African landscapes (ranging from dense urban areas to smallholder croplands to timber plantations) are impacting the populations of species that they know about, in the regions where they work. Some experts can answer this question for snakes in Benin, while others can answer it for elephants across east Africa.
Expert elicitation is common where data are lacking, with uses ranging from military to business to biosecurity. We bring together experts per taxonomic group (eg all reptile experts) in an online introductory meeting. We explain that we would like each expert to complete a survey in their own time over a two-week period, where they provide their ‘best-guess’ estimates for how the abundance of different groups of species (eg large lizards, small snakes, tortoises) is likely to be impacted by nine typical African landscapes (including dense urban areas, suburban areas, intensive croplands, smallholder croplands, rangelands, etc). Impact is thought of relative to a reference state: how abundant would these species have been before modern industrial society? Experts’ estimates are on a scale of zero (e.g. no large snakes remain in intensive croplands) to one (‘intact’ – e.g. the abundance of small lizards in a protected area is the same as their abundance would have been in pre-industrial times). Experts base their estimates on their extensive experience observing these species in the relevant landscapes. We collate the estimates and then present aggregated results back to the group in another online meeting, facilitating a critical and reflective discussion of the emergent patterns and uncertainties.
This simple approach enables us to collect comparable estimates across all types of biodiversity across the continent, creating a picture of how changing landscapes are impacting biodiversity intactness. The indicator that emerges from this process allows us to map biodiversity intactness (on a scale from zero to one) across the continent – giving insight into how changing human landscapes are impacting the full spectrum of life on the continent. Importantly, this measure of biodiversity comes from the people who know best – those that work in these landscapes every day and witness their impacts on biodiversity.
Payoff
We are starting to see some interesting results. Species vary dramatically in their ability to cope with human pressures. Bats and birds seem to cope better than many other groups of species, likely because they are highly mobile. It’s not uncommon to see bats roosting in roofs in a city or birds in a suburban garden. This said, large birds of prey, like eagles, do not cope well, and even our protected areas aren’t able to conserve the numbers we would like, given how widely these species roam and how susceptible they are to human persecution. Similarly, large mammals like lions, rhinos and antelope that require extensive areas and a lot of food, disappear rapidly in human-dominated landscapes. Amphibians do not cope well in human environments either. They may be small, but many are reliant on good quality water habitats like wetlands to breed, and these are often highly modified by people and their livestock. Amphibians are also very sensitive to pollutants.
In addition to insights into how different species cope with changing landscapes, we are also learning that the type of landscape transformation matters. It is no surprise that highly urban environments, with a lot of concrete and people, are particularly harmful to most species. Fortunately, these landscapes tend to be quite contained, taking up a small portion of the total land area. Arguably more concerning is the general inability of species to cope with large-scale croplands or timber plantations, which take up considerable and increasing areas across the continent. Intensive agriculture typically homogenises a landscape – crops remove trees and shrubs while timber plantations remove understory vegetation. Biodiversity needs a diversity of habitats.
Chemical inputs like fertilizer and pesticides are also problematic for species. By contrast, many species are still able to persist with people in smallholder croplands, which cover a large portion of sub-Saharan Africa. This type of agriculture typically comprises smaller fields with a greater diversity of crops and fruit trees, and less mechanised harvesting that is also more staggered in time. There is, therefore, a concern that if agriculture across Africa becomes intensified to meet the demands of development, this will have significant implications for the remaining biodiversity in these agricultural landscapes.
Once completed, this biodiversity intactness index will be made freely available in an easily usable way on a dedicated website, enabling the integration of biodiversity and its services into national accounting. Through this highly collaborative process, hundreds of Africa’s biodiversity experts will have teamed up to mainstream nature into decision-making for a more just and sustainable future for all on the African continent.
This article first appeared in Africa Geographic on 10 November 2021.
Dr Hayley Clements is a Researcher at the Centre for Sustainability Transitions, Stellenbosch University, South Africa (https://www0.sun.ac.za/cst/). You can learn more about the project she is leading to quantify Africa’s Biodiversity Intactness Index on the website www.Bii4Africa.org, and meet the participating experts. This project is supported by a Jennifer Ward Oppenheimer Research Grant.
RESOURCES:
1 – Archer et al., eds., Regional Assessment Report on Biodiversity and Ecosystem Services for Africa (Bonn: IPBES, 2018), https://ipbes.net/assessment-reports/africa.
2 – https://royalsocietypublishing.org/doi/pdf/10.1098/rstb.2015.0312
3 – World Travel and Tourism Council https://wttc.org/
4 – United Nations World Tourism Organisation (UNWTO) (2020). Country profile: inbound tourism. Available at: https://unwto.org/country-profile-inbound-tourism
5 – World Travel and Tourism Council https://wttc.org/
6 – United Nations Economic Commission for Africa (UNECA) (2016). Demographic profile of African countries. United Nations Economic Commission for Africa, Addis Ababa. Available at:https://www.uneca.org/sites/default/files/PublicationFiles/demographic_profile_rev_april_25.pdf
7 – African Union, Economic Commission for Africa; African Development Bank and United Nations Development Programme (2019). 2018 Africa Sustainable Development Report:
Towards a transformed and resilient continent. AU ECA, Addis Ababa. Available at: https://www.uneca.org/sites/default/files/PublicationFiles/asdr_2018_en_web.pdf
8 – http://www.ncbi.nlm.nih.gov/pubmed/30904104
9 – Archer et al., eds., Regional Assessment Report on Biodiversity and Ecosystem Services for Africa (Bonn: IPBES, 2018), https://ipbes.net/assessment-reports/africa.