How can we balance people's needs with conserving biodiversity?

Is it possible to use natural resources effectively and protect the Earth's wildlife and biodiversity? Oxford University scientists have proposed a new framework that could achieve exactly that. William Arlidge, a doctoral student and Professor EJ Milner-Gulland, Tasso Leventis Professor of Biodiversity; Director, Interdisciplinary Centre for Conservation Science; Fellow of Merton College, discuss their new research as featured in BioScience.

In an effort to help answer one of the biggest questions in conservation,  in our new paper we discuss whether a framework used to reduce negative impacts from development on biodiversity could be expanded to account for all human impacts on nature. 

Biodiversity is the variety of life in all its forms on planet Earth. It’s a broad concept, and conserving it is complex as it needs multifaceted approaches that are aimed at understanding what is most valuable, and at most risk, and what are the best approaches to undertake conservation that is not at odds with other societal needs. Our current efforts to do so comprise a patchwork of international goals, national plans, and local interventions. While our conservation efforts are not without great successes, overall, they are failing to achieve all their desired outcomes. This is largely down to us, because human needs for ever-more space to grow food, harvest wild products like timber and fish, and build infrastructure, are squeezing out nature.

Our continued use of biodiversity to improve our wellbeing is, sadly, all too often in conflict with our efforts to conserve it. At the broadest scale the United Nations Sustainable Development Goals provide a global vision to conserve and sustainably use biodiversity, however guidance on how this broad vision translates to actions at national, regional, and local levels is not clear.

In our new publication, we propose taking a more systematic approach to achieving biodiversity conservation goals, by accounting for all human biodiversity impacts and conservation efforts within a unified global framework.

This framework expands on an existing concept known as the ‘mitigation hierarchy’, which offers a balanced and systematic way to account for and mitigate harmful impacts to biodiversity, while still allowing development activities to occur.

The mitigation hierarchy works by first trying to predict all the negative impacts that are likely to occur as part of a given activity. Creating a palm oil plantation, for example, will mean directly losing some tropical forested areas and their associated biodiversity. There will also be other more indirect impacts such as the risk of sedimentation, pollution and noise disturbance. To account for all these different impacts, sequential steps are taken: developers need first to consider the extent to which they can avoid causing damage. Then they need to minimise the damage they cause from their operations. Next, they should remediate any temporary damage. All these steps mitigate biodiversity impacts on site. Following the implementation of these steps, any residual impacts to biodiversity not mitigated must be offset by boosting biodiversity elsewhere.

Avoiding impacts could include selecting sites that have no biodiversity impact or foregoing the development effort all together. Minimisation could include restricting heavy machinery used to remove palm oil to particular roadways and halting construction during sensitive times. Remediation could include reinstating roads to their previous condition once they are finished with. Offsetting might include replanting forest habitat elsewhere. The logic in undertaking these steps is to achieve a neutral or positive level of impact to biodiversity after a given damaging activity (often referred to as ‘No Net Loss’ or a ‘Net Gain’ of biodiversity).

While the theoretical and practical challenges in achieving No Net Loss of biodiversity are becoming increasingly well described and reported (see papers from Joe Bull, Martine Maron, and David Lindenmayer), the underlying concept of the mitigation hierarchy is both powerful and much more widely applicable than has so far been appreciated.

Currently there is a widespread and piecemeal project-level approach to achieving No Net Loss of biodiversity taking place. This means that, if biodiversity gains and losses were to be aggregated, biodiversity could be lost even if individual projects appear to be reaching their targets. If the concept is to truly have biodiversity benefits, there is a need for a multi-scale approach to No Net Loss, so that wider goals are not contradicted by project-level use of the mitigation hierarchy.

In our publication we propose the use of the mitigation hierarchy to navigate the conservation-development trade-off at the broadest scale possible, the whole planet. Incorporating all human impacts on biodiversity within the single standardised paradigm with a broad biodiversity conservation goal. Crucially, a global mitigation hierarchy offers a systematic framework that is both scalable from the project to the national and international levels, as well as being standardised between the conservation sectors of sustainable use (e.g., certification schemes), minimising the impact of development (e.g., No Net Loss), and efforts to directly restore or protect sites (e.g., protected areas).

Conserving biodiversity while simultaneously seeking to use it for humanity's needs is a huge challenge, which some suggest is not possible on our current growth trajectory. Others have called for half the planet to be set aside for biodiversity conservation, or for more space to be given to nature. But in the absence of a clear pathway to achieving it, it is difficult to see how these aspirations can translate into real biodiversity gains. Our approach cannot solve all of these challenges, but what the mitigation hierarchy offers is transparency, enabling clear understanding of what the consequences of various uses of nature are, with flexibility to address a variety of human impacts on biodiversity, across different sectors and scales.

Fundamental changes are needed if humanity is to reverse the current biodiversity crisis and put the planet on a sustainable course for the future. However, these changes will only be possible if we can see a way forward. Quantifying and accounting for all human-caused impacts to biodiversity could help humanity to reduce these impacts in a feasible and equitable way. A global mitigation hierarchy could be the first step towards achieving such a vision.