The importance of biodiversity and corporate social responsibility is placing more and more onus on developers to put nature first. This is especially relevant given the changes in legislation from late 2023, stipulating that a 10% biodiversity net gain will become law. 

What is the mitigation hierarchy?

Mitigation hierarchy is a widely used framework that businesses, developers and ecologists can follow in their efforts to avoid, minimise, restore or offset biodiversity loss. A mitigation hierarchy is a set of guidelines as opposed to a legislative framework, and developers can utilise it to clearly define and establish how to improve the biodiversity value of the project.

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Is the mitigation hierarchy process a legal requirement?

No. Currently, there is no legal requirement to follow the mitigation hierarchy process as a single entity or measurement. However, it is often an appropriate benchmark to aim for and refer to, as it is seen as established and universal. This means that investors, stakeholders, developers, ecologists and third parties can all comprehend the potential biological impact of a project, and work from a proven process to control any negative effects as best as possible. This includes impact on the surrounding ecosystem, as well as any protected species habitats that will be interfered with.

When the mitigation hierarchy guidelines are followed along with regular project planning, it can have an incredibly positive impact and influence on a development project. The intensity of the environmental impacts can be either reduced, mitigated or avoided, to the benefit of stakeholders and developers as well as any notable biodiversity in the area. This may even result in the location site being changed, or alternative development practices being used after a discovery has been made. 

How mitigation hierarchy works

Mitigation hierarchy works on the basis that development plans will try and aim for as little biodiversity loss as possible. The measurement of biodiversity loss can be categorised into the following four stages: 

• Complete avoidance

• Minimisation, where possible 

• Restoration of areas within the development 

• Offsetting, either onsite or offsite

Depending on the development budget, mass land area, and habitat scope, a project may be able to avoid ecological impact completely. In worse-case scenarios, where biodiversity impact cannot be avoided or minimised, then developers will include plans to enhance the biodiversity onsite or offset the loss of biodiversity. 

These four ‘options’ or ‘stages’ make up the mitigation hierarchy framework, and when followed, can help ensure that no development site causes environmental damage that cannot be mitigated. 

The four stages of mitigation hierarchy

We look into the four stages in more depth below. 

Stage 1: Avoid

Avoidance is the first step you can take in ensuring that biodiversity loss is as reduced as possible. There are plenty of gains that can be achieved with avoidance, as it’s the most effective solution ecologically. Not only can a no-net-loss outcome be achieved through avoidance, but it can also save money that would otherwise have to be spent on mitigation strategies. 

Benefits of avoidance

• Complete avoidance ensures a tangible benchmark of success to investors and stakeholders. 

• Complete avoidance removes any time delays on the project. Other solutions (minimisation, restoration and offsetting plans) will likely need a timeline for completion. 

• Complete avoidance is an incredibly attractive consideration to third parties, especially when regarding the legislative changes surrounding biodiversity net gain and land management.

What to consider before aiming for avoidance

Significant upfront costs

There may be significant upfront costs involved if you are planning to ensure your project avoids any biodiverse impact whatsoever. 

Potential initial delay 

Avoidance measures can also alter initial plans and timeframes for the project start date, meaning that you may not get going with the project as quickly as you may like. 

Complete avoidance can be less noticeable to stakeholders

In some cases, you may find that details of previous planning are not shared with stakeholders, meaning that they may not even be aware of the lengthy (and potentially costly) steps that have been involved in ensuring complete avoidance. 

How to avoid environmental impact successfully

Consult with the right people 

To achieve complete avoidance, consideration will need to be made very early on in the project. If you’re aiming to avoid any impact at all it’s worth consulting with ecologists, engineers, and geoscientists before your development site is even selected. 

Plan far in advance

You will need to plan far in advance to make sure you outline your project to completely avoid areas of high biological value. For example, you may need to reroute a road or a pipeline to avoid a valuable habitat. 

Stage 2: Minimise

Minimisation is officially the next stage in the mitigation hierarchy, applied to situations where complete avoidance is not possible. 

What does minimisation mean?

If avoidance is impossible, and you may find that the best route is project impact minimisation. Minimising the overall environmental impact can help to adequately manage issues that cannot be avoided. This is achieved by adapting the project or devising ways to reduce the biodiversity impact.

Benefits of minimisation in the mitigation hierarchy process

Minimisation is more noticeably evident to stakeholders 

Minimisation can be more visible and tangible compared to avoidance measures, which means stakeholders are more likely to be on board as they are physically able to see and understand the measurements being taken to protect biodiversity. 

Minimisation allows for more flexibility with the budget and/or timeframe

The planning and implementation of mitigation measures can occur adaptively throughout the project, meaning that ideas and solutions are not limited to a certain time frame or budget. 

Minimisation can result in new technological discoveries 

In some instances, minimisation may bring about some positive outcomes that can emerge from a technological standpoint. This can happen when a new innovative and technological approach is necessary to reduce impact, offering more scope and possibilities for similar projects in the future. 

What to consider before aiming for minimisation

It can be difficult to monitor and report the results of minimisation

Project impact minimisation can be challenging to monitor and report on. This is because it can yield results with no baseline or previous measure of success to work from. This can especially be the case if a new technique or solution has been applied or an unproven approach has been tested. 

It is much harder to predict costs 

You may end up with open-ended costs when you try and minimise the environmental impact of a project. This is because the most suitable solution for minimisaton could involve an approach that hasn’t been attempted previously. As there will be no way to accurately predict how much money is needed, you could find yourself spending more than originally planned. 

Examples of PROJECT IMPACT minimisation

Physical controls

This can involve adopting physical adaptations to the infrastructure and design of development with a net aim to reduce any environmental impact. 

Operational controls

Operational control involves regulating parts of the project to help reduce environmental impact whenever possible. For example, effective soil minimisation is an example of operational control. It can also refer to reducing practices which have the potential to negatively impact the surrounding area in any way. 

Abatement controls

Abatement controls include actions such as reducing the levels of pollutants, emissions, dust, light, noise and gas. Abatement controls of this nature will likely need engineering expertise, as you may need advice on how to reduce the physical impact affecting the surrounding area. 

How to minimise environmental impact successfully

Plan project impact minimisation early on

It’s advised that minimisation is best placed early in the lifespan of a project, ideally before any major decisions have been made. 

Have a creative approach

Creative thinking is essential to the mitigation process, and occasionally community-based minimisation actions can help. 

Consider community participation 

Effective community participation can bring a positive sense and communal feel to your project. Promoting awareness of the project, or providing information on upcoming job opportunities, for example, can demonstrate an awareness for the surrounding community. Consider how you can involve the community or keep them informed and included in a way that's mutually beneficial. 

Stage 3: Restoration

Restoration refers to the measures taken to repair degradation or damage to any features of a project. Restorative actions are only implemented once an area has been damaged. This is the standard practice, as it allows project managers to adequately assess the scale of the restoration required. 

What does restoration mean in biodiversity mitigation hierarchy? 

Restoration can mean lots of different things. From the re-establishment of product lands, to enhancing existing habitats, to specific conservation values and maintaining natural habitat connectivity.

Biodiversity restoration: What to be aware of 

• Generally more challenging to execute

• More uncertain than other solutions (avoidance, minimisation) 

• Although restoration aims to reverse impact damage directly, there is often a significant delay between the initial environmental impact occurring and evidence of restorative gains. This can cause issues for stakeholders if they are relying on results and for investors or stakeholders expecting a positive outcome in the short term. 

• You can research, prepare and plan for restoration within your mitigation hierarchy strategy, but, unlike avoidance or minimisation, restoration will require ongoing management. 

Stage 4: Offsetting

What is offsetting in mitigation hierarchy?

Offsetting is the process whereby any net loss caused by a land development is offset. This can help ensure the development achieves net gain by completion. Often, biodiversity offsetting cannot be achieved onsite. This can be due to lack of space or limitations from a legislative standpoint. In such instances, it isn’t uncommon for developers to plant trees and create woodland or wetland on other sites that are geographically located elsewhere. On the basis that biodiversity net gain will be achieved overall, offsetting provides the perfect way to redeem any ecological value lost, regardless of the site space itself. 

Biodiversity offsetting: What do consider

Technical considerations are a key step in delivering biodiversity offsetting.  There will need to be a clear format for how data will be collected and presented as well as how outcomes will be measured to prove overall net gain. 

Biodiversity offsetting will impact project management, stakeholders, economical and sustainable considerations as well as local governance considerations. This is why solutions and outcomes need to be established and proven before the project begins. Remember, the overall aim of biodiversity offsetting is no net biodiversity loss. 

Stages of biodiversity offsetting 

• Scoping

• Screening 

• Feasibility 

• Design 

• Management planning

• Offset implementation 

Remember that occasionally, net gain won’t be able to be achieved on-site. In this case, development authorities will need to undertake environment conservation activities to compensate and achieve ‘no net environment loss’. 

Benefits of the mitigation hierarchy

With this established and popular framework, it is easier for developers and stakeholders to deliver a net positive project. The hard work is done for you in that it can easily indicate the type of preventative action required from a set precedent. In recognising mitigation hierarchy guidelines, you can advantageously reassure investors, ecologists and stakeholders who are invested in biodiversity restoration. 

Explore our biodiversity net gain services and mitigation services at Ecology by Design. Head to our blog for more insights or explore our other ecology services and discover how Ecology by Design can help you with your project today.