Biodiversity Net Gain Assessment for Residential Development in Lyminge, Kent

Southwest Environmental Limited was commissioned by an individual to prepare a Biodiversity Net Gain (BNG) Report for a proposed development located in Lyminge, Kent[cite: 2]. The project site is situated within the planning authority of Folkestone and Hythe District Council[cite: 2]. The proposed development involves the stationing of one mobile home, complete with a utility block, parking areas, and access roads[cite: 2]. This project was completed with a short lead time to ensure the applicant could proceed with their planning submission without delay.

Baseline Ecological Conditions

A site visit was conducted by a Project Ecologist to establish the baseline ecological conditions[cite: 2]. The methodology followed standard UKHab survey practices[cite: 2]. The site predominantly consists of Other Neutral Grassland in poor condition, alongside developed land with sealed surfaces and artificially unvegetated unsealed surfaces[cite: 2]. The baseline biodiversity value was calculated using the Statutory Biodiversity Metric Calculation Tool (Defra, 2025, version 1.0.4), in accordance with the mandatory requirements set out in the Environment Act 2021. The baseline evaluation yielded 0.88 Habitat units and 0.00 Hedgerow units[cite: 2].

Tonbridge Castle gatehouse and adjoining Georgian mansion, A Kentish Landmark.

Proposed Mitigation and Biodiversity Enhancements

To meet the statutory requirement of a 10% net gain, a comprehensive landscape plan was developed[cite: 2]. The primary mitigation strategy involves the enhancement of 3,300 square meters of the existing Other Neutral Grassland from a “Poor” to “Moderate” condition[cite: 2]. This will be achieved by implementing a strict cutting regime and removing arisings to reduce soil nutrient levels, coupled with the introduction of native wildflower species[cite: 2].

In addition to grassland management, the project requires the planting of 63 meters of native hedgerow to achieve a “Moderate” condition[cite: 2]. The species mix will include native varieties such as Hawthorn, Blackthorn, Hazel, and Field Maple, providing vital connectivity for local wildlife[cite: 2]. Additional ecological recommendations include the installation of bat boxes, bird boxes, invertebrate habitats, and hedgehog houses[cite: 2]. Lighting protocols were also stipulated to prevent adverse impacts on nocturnal invertebrate and bat populations[cite: 2].

Metric Outcomes and Reporting

Following the application of the specified mitigation measures, the post-development metric calculations demonstrate that the site will deliver 0.11 Habitat units and 0.21 Hedgerow units[cite: 2]. This equates to a 12.14% net gain in Habitat units, successfully exceeding the mandatory 10% threshold[cite: 2]. All trading rules have been satisfied through the beneficial increase of medium distinctiveness habitats[cite: 2].

The full methodology and calculations are documented in the formal report, available in the file named GreenLane_BNG.pdf, and supplementary operational notes are recorded in the file named Business Update & and Blog from report .txt. A 30-year BNG Management and Monitoring Plan will be established to secure the condition and persistence of all new and enhanced habitats[cite: 2].

For further information on our ecological services and statutory metric calculations, please visit the Biodiversity Net Gain services page on www.southwest-environmental.co.uk.

Please contact us if you would like a fixed price quotation.