Survey and Mitigation Calendars

Key points

• Your starting point is a Preliminary Ecological Appraisal (PEA). This desktop and walkover survey identifies what habitats and species may be present. It sets the risk profile and determines what further surveys are needed.
• A PEA alone is usually insufficient for planning permission.
• Be aware of seasonality – some surveys can only be actioned at certain times of year (see our survey and mitigation calendars).
• Allow enough time following surveys for the licenses to be obtained (if required).
• An Ecological Impact Assessment (EcIA) is required to support planning applications, especially if significant ecology features are identified. This is a detailed report based on the results of the PEA and any follow-up surveys.
• Biodiversity Net Gain (in England) or Net Benefit for Biodiversity (in Wales) becomes easier with early ecology engagement.

Ecology isn’t a box to tick at the planning stage; it’s a critical element to address upfront. The earlier you factor ecology into the planning process, the more certainty you have around your options, the better you can arrange your priorities to hit your deadlines. Engaging early with the ecology programme give visibility to your risks — and your opportunities. 

What is a Preliminary Ecological Appraisal (PEA)? 

A Preliminary Ecological Appraisal (PEA) is a rapid assessment of the ecological features at a site, often used to inform larger Ecological Impact Assessments (EcIA).  

A PEA is typically the first stage in assessing a site’s ecological value. It usually involves a desk study (reviewing existing data) and a site walkover or survey to identify potential ecological features. The PEA helps identify potential ecological constraints, mitigation measures, and whether further surveys (like bats, badgers or habitats) are needed. 

If a project is known to have likely impacts on ecological features, then a PEA report may not be needed, and the same desk study and survey effort can inform the detailed surveys to be reported in the EcIA. In this case the data collected will be the same, but reporting time and costs can be reduced. 

“Ecological Triage” 

We offer a Rapid Ecological Walkover, a high-level ecological triage for early-stage decisions. It’s not a substitute for a full PEA, but it helps flag major ecological risks and constraints before site acquisition or major design decisions. This provides clarity and sets expectations early in the planning process. 

What is an Ecological Impact Assessment (EcIA)? 

An EcIA is a more in-depth study that evaluates the potential impact of a development or other works on habitats, species, and ecosystems, and is required for projects where ecology impacts cannot be ruled out.  

The EcIA builds upon the PEA or walkover survey, often incorporating further targeted surveys and assessments to identify specific impacts on protected species or habitats. The EcIA provides a detailed assessment of potential impacts, mitigation measures, and any necessary compensation for ecological damage or enhancements which are being proposed by the project team. Unless impacts on ecological receptors can be entirely ruled out, an EcIA is the minimum required for planning applications to present to your local authorities. 

Survey Calendar 

Ecology is seasonal. Great crested newts (GCNs), bats, badgers, and breeding birds, for example, all have specific periods in which the baseline must be established, known as the ‘survey window’. Missing a particular survey window can cause up to a year’s delay. 

 A site with protected species, such as active badger setts or dormice, may require multiple surveys and licenses, some only available during specific times of the year. 

For instance, a developer may wish to submit for planning in 6–12 months but miss the spring GCN and breeding bird survey windows in the first year. They could be looking at another full calendar cycle of delays.  

Multiple survey visits may be required 

Repeat survey visits by ecologists may be required, which must take place at a specific point of the year which is dependent on the type of survey. You must be aware of this as early as possible in the planning process to ensure this is factored into your programme.  

For some species, like bats, survey requirements are nuanced — taking into account bat species, roost location and roost type. Others, like breeding birds, can only be surveyed during short seasonal windows. You may need multiple survey visits across different months to get a full picture. 

Mitigation and Licensing 

Certain species and habitats are protected by law. If your impacts are unavoidable, mitigation must be planned for and licensed appropriately — such as relocating badgers or bats, which may require months of lead time. See our Mitigation Calendar:

Certainty Comes from Clarity 

Early ecological assessments help to de-risk sites, such as those provided by Cura Terrae Land and Nature. We’re solutions-focused and aim to provide a high level of expertise, gained across multitudes of sites and projects.  

Ecology input is not a barrier, but it does need to be understood and planned for. A site may have multiple ecological features and remain viable for development. The earlier you understand the ecological requirements, the more certainty you have, and the more options you have to realise your design ambitions.  

Our ecologists are here to bring clarity, reduce risk, and help your project succeed on schedule.