DOI: 10.5061/dryad.d7wm37qb9
title: Data from: Using past planning practice to inform biodiversity net gain in residential developments

description: Urban growth is a major driver of biodiversity loss, as natural habitats
 are destroyed or fragmented. To address this, nature-positive initiatives
 aim to balance development with nature conservation. In the UK,
 Biodiversity Net Gain (BNG) was introduced through the 2021 Environment
 Act requiring developers to deliver a minimum 10% biodiversity increase
 for new developments. Despite BNG's potential, doubts exist about
 local planning authorities’ (LPAs) ability to implement and enforce BNG
 effectively, due to resource limitations, inconsistent ecological
 expertise, and ineffective monitoring. This study examined 44 residential
 developments across two case studies where biodiversity measures were
 mandated through prior planning policy and assessed i) how well ecological
 advice was integrated into planning decisions, and ii) whether
 biodiversity measures were effectively implemented. The study revealed
 significant gaps between approved plans and actual implementation. The
 ecological advice transposed into planning decisions and approved
 documentation, was biased towards European protected species (EPS) or more
 charismatic fauna. Additionally, many developments failed to properly
 implement biodiversity measures, with frequent deviations from approved
 plans for artificial and semi-natural habitats. Solution: Improved
 awareness and knowledge of biodiversity, increased LPA resource, better
 communication between planners, ecologists, and developers, stronger
 enforcement, and improved monitoring are essential for BNG’s success.
 Without these actions, BNG may fail to leave the natural environment in a
 measurably better state.
description: This study uses two case studies, covering 44 residential
 developments across six LPAs. Specific details of the planning
 applications have been withheld to protect anonymity. Case Study 1 covers
 35 developments in five LPAs with decisions made (including three
 refusals) between 2012 and 2016, and informed Stage 1 and Stage 2 of this
 study. Case Study 2 considers 9 developments in one LPA, permitted between
 2012 and 2018 and informed only Stage 2 of this study. All developments
 were within the 4-year planning aftercare period, but no development
 specifically required post-development monitoring embedded within the
 conditions that related to biodiversity (e.g., the submission of a report
 by a suitably qualified ecologist), nor were any financial securities
 attached to the delivery of ecological features.
 <strong>Case study 1: Central
 England</strong> In Stage 1, 29 residential
 developments between 2 and 100 dwellings in size, across five LPAs in
 Central England, whose decision was made after NPPF publication
 (26<sup>th</sup> March 2012), were subject to a review of the
 extent to which statutory ecological advice was transposed into the
 planning decision notice, in Stage 2, 19 completed developments were
 visited and assessed for how well biodiversity measures were
 implemented. <strong>Stage 1: Review of ecology
 advice and decision notice</strong>Stage 1: Review of ecology advice
 and decision notice For each planning application, the
 decision notice, the ecological advice provided to the case officer, and
 for additional context, the case officer's report was accessed via
 the respective planning portal for each LPA. Where any documents were not
 provided, the planning authority was approached directly. Both the EA and
 the biodiversity-relevant condition statements within the PDN were
 categorized according to broad (e.g., landscaping) and specific (e.g.,
 species) categories and counted. A count was made of the number of
 developments where each category was referred to at least once as, either
 a recommendation from the EA or as a condition within the PDN.
 Biodiversity and landscape management plans submitted in the discharge of
 a condition were further checked for the inclusion of specific measures
 that may have been recommended.  <strong>Stage 2:
 Site inspection to assess accordance with approved
 documentation</strong> Approved documents were
 obtained for 11 completed developments assessed in Stage 1 plus an
 additional 8, which contained biodiversity measures within the approved
 documentation, but EA was not available. ‘Approved documents’ included
 those within the PDN or those approved for discharge of a planning
 condition relating to biodiversity, although not always directly, e.g.,
 submitted through landscaping and planting schemes.
 Each development was visited between February and March 2016,
 with wetland or wildflower interventions revisited during June and July.
 Minor or major deviations were noted (Table 1) within six broad habitat
 features: hedgerows, trees, wetlands, wildflower grassland, artificial and
 other. Deviations could also be positive, such as additional bat boxes.
 Site visibility was variable; averaging 72.3%, min. 37.4%, max. 100%
 (calculated by dividing plans’ line-of-sight visible area by site
 area). <strong>Case study 2: Southwest
 England</strong> Nine residential developments
 were visited in July 2021, ranging from 9 to 433 dwellings in a single LPA
 in southwest England, where planning permission was granted after NPPF
 publication. Each development had some biodiversity measures secured as
 part of the planning permission, concerning species groups (e.g.,
 artificial measures for EPS), or habitat / habitat features (e.g. trees,
 grasslands or hedgerows). The approach taken differed from Case Study 1,
 including a compliance score calculated within each feature (Table 2), as
 a proportion of the proposed measures that were implemented at either a
 unit level or species level. This value was then averaged across each
 development to give an overall non-compliance score.
description: # Using past planning practice to inform biodiversity net gain in
 residential developments
 [https://doi.org/10.5061/dryad.d7wm37qb9](https://doi.org/10.5061/dryad.d7wm37qb9) ## Description of the data and file structure This study examined 44 residential developments across two case studies where biodiversity measures were mandated through prior planning policy and assessed i) how well ecological advice was integrated into planning decisions, and ii) whether biodiversity measures were effectively implemented. ### Files and variables #### File: CaseStudy2\_Stage2Compliance.csv **Description:** From Case Study 2, the compliance score (Install.score) for given ecological features intended to be implemented, per site. ##### Variables * Site: The anonymised site * Feature: The group of ecological features * Install.score: The degree of compliance, as described in the methods #### File: CaseStudy1\_Stage1.xlsx **Description:** The number of mentions for different ecological features from the ecological advisor (EA) and in the Planning Decision Notice (PDN) and associated documents with conditional discharges. ##### Variables * Authority: The anonymised authority * Development: The anonymised development * UID: Authority + Development * Decision: The outcome of the planning application * x_EA: Ecological feature (x) mentioned (1) or not (0) by the ecology advice * x_PDN: Ecological feature (x) mentioned (1) or not (0) by the Planning Decision Notice or associated documents with conditional discharges. * NA values refer to instances where ecological advice could not be located. #### File: CaseStudy1\_Stage2Deviations.csv **Description:**  ##### Variables * Order: Row order * Site: Anonymised site * variable: For example: Cnt.Min.Hedg = Cnt = Count, Min = Minor or Major deviation (see methods), Hedge = Hedgerow * value: Number of minor or major deviations or NA = feature not applicable to the site * MinMaj: Minor or major deviation * Feature: Ecological feature **Code/software** Microsoft Excel or R / RStudio **Access information** Other publicly accessible locations of the data: * None Data was derived from the following sources: * None