When will ecological evidence be needed?
The need depends on the site, the development and the likelihood of effects on protected species or habitats, not simply on the number of homes proposed. Natural England's standing advice identifies development activities and site features that can trigger further investigation. The council needs enough information to understand the effects before deciding the application. [1]
For a roof alteration, demolition or tree work, ask an ecologist to assess the relevant features before the design and programme are fixed. A preliminary visit can identify whether a more specific survey is necessary; it should not be sold as a guarantee that no later survey will be required.
What is the difference between an appraisal and a bat survey?
An initial ecological appraisal draws together the site's ecological context and the potential implications of the work. Its useful output is a clear account of constraints, further information needed and opportunities to avoid or reduce impacts. Where protected species may be affected, follow-up surveys must be suitable for the species and the proposed activity. [1]
Bat work may involve assessing the suitability of a building or tree and, where necessary, further surveys to establish use. Bats and their breeding sites or resting places are protected; the absence of a visible bat during one inspection is not a reliable basis for assuming that a roost is absent or unprotected. [2]
Who prepares the reports?
Use an ecologist with relevant survey competence and experience of the habitats or species involved. Activities that would otherwise disturb protected bats can require an appropriate licence. Ask the consultant to explain which work is included, whether licensing is relevant and what evidence the council will receive. [1] [2]
A useful appointment separates the initial appraisal, any further surveys, assessment of the final design and assistance with mitigation or licensing. This makes it easier to compare scope without assuming every property needs the same survey package.
Allow for the survey programme
Protected-species surveys can be seasonal. Natural England advises that the necessary information should normally be available before determination rather than left to a condition that might reveal a fundamental problem afterwards. Establish the programme with the ecologist before choosing a submission date. [1]
Give the consultant the latest demolition and proposed drawings, access to relevant parts of the site and any existing ecological reports. Ask what could make earlier information unsuitable, including changed site conditions or a materially different proposal.
Ecology is not the same as BNG
From 6 August 2026, the BNG exemptions changed, including the new exemption for sites of 0.2 hectares or less where its conditions are met. A BNG exemption does not remove protected-species assessment or licensing requirements. Treat the exemption check and the ecological impact assessment as separate questions. [3] [2]
Finally, transfer the agreed avoidance and mitigation measures into the drawings and construction information. A report that recommends retaining a feature is not coordinated if the demolition plan still removes it.