In response to the global biodiversity crisis, several targets and commitments have been drawn up to help track progress towards protecting and enhancing forest biodiversity. However, landowners and forest managers often lack the necessary information and tools with which to evidence progress towards these obligations and justify decisions.
One major challenge in monitoring and reporting biodiversity trends is finding indicators that are scalable, repeatable and easy to interpret, while also capturing the complex and multi-dimensional nature of biodiversity. To address this challenge, Forest Research (FR), Forestry & Land Scotland (FLS) and Forestry England (FE) have developed, in collaboration, the Forest Biodiversity Index (FOBI).
The FOBI provides a quantitative, transparent and repeatable method for mapping and monitoring the biodiversity potential of our forests. It incorporates proxies of biodiversity that characterise the trees and structures within woodlands, and features of the landscapes surrounding them, such as tree age diversity, open habitat cover, and woodland connectivity. These indicators, or ‘FOBI metrics’, have generalisable associations with woodland biodiversity evidenced in the literature that tend to hold true across different woodlands and contexts. For example, we know that higher tree age or size diversity are typically positively related to other facets of woodland biodiversity, such as genetic or species diversity. Unlike taxonomic or trait-based biodiversity indicators, these structural metrics of ‘biodiversity potential’ are generally:
To encourage the use and communication of the results by decision makers, politicians and the public, the metrics are combined to provide headline measures of biodiversity potential. The FOBI expert group iteratively co-developed and refined a stepped approach that groups the metrics by the scale at which they are measured (local, ‘within woodland’ metrics and landscape, ‘surrounding woodland’ metrics) and their theme (diversity, condition, extent, and connectivity). A Local and a Landscape FOBI are provided at the highest level of the FOBI.
As the combination of multiple measures into a ‘composite index’ can be statistically problematic and provide misleading results, only positively correlated metrics are grouped following best practice guidance. Although this reduces the complexity captured, all levels of the FOBI, including the full set of metrics and the resulting composite indices, are provided to end users. The layered and scalable outputs therefore provide for both strategic decision-makers requiring high level information for regional- to national-level reporting, and for forest planners and managers that require woodland-level metric information for spatially targeted management.
The FOBI was originally co-developed and applied to the Public Forest Estate in England and Scotland by FR, FE and FLS. These publicly owned forests account for around a quarter of woodland area in the United Kingdom. The Public FOBI is measured for every public ‘FOBI woodland unit’, which are groups of adjacent sub-compartments, or stands, falling within the same management zone. Many of the Public FOBI metrics are directly measured from the ‘subcompartment database’, a continually maintained, stand-level forest survey database. Others are modelled or derived from other spatial environmental datasets. The same outline approach is applied to England and Scotland, however the metrics calculated diverge slightly due to data availability. A detailed description of the methods used for calculating the Public FOBI, with example results exploring changes in the FOBI over time in England, are available as an open access journal paper (Bellamy et al., 2024).
The Public FOBI was initially calculated for a single historical year – 2014 in England and 2011 in Scotland – and for the 2019 baseline year. Since 2019, the Public FOBI results are provided on an annual basis by country, enabling changes in forest biodiversity potential to be assessed over time and space. FR, FLS and FE staff can explore all FOBI metric and index scores by country for internal business via:
Explore our interactive StoryMap for a dynamic, visual walk through the FOBI project and its application to Scottish public forests (please click on the image below).
We are currently collaborating with several forest owners to explore how the FOBI approach can be applied to private forests. In the absence of the subcompartment database used for calculating the Public FOBI, we are assessing the feasibility of using remote sensing data alongside survey data from private forest owners.
Compared to other forest biodiversity indices, the FOBI meets all the following criteria:
If you have questions or would like to explore application of the FOBI to your forests, please get in touch with chloe.bellamy@forestresearch.gov.uk.
More details on the FOBI approach and results of the Public FOBI are provided in an open access journal paper and supplementary material: Bellamy, C.C., Rattey, A., Edwards, C., Kortland, K., Stringer, A., Tew, E., Bathgate, S., Kerecsenyi, N., Moseley, D., Watts, K. and Broome, A., 2024. The forest biodiversity index (FOBI): monitoring forest biodiversity potential over space and time. Environmental Research: Ecology.
The Public FOBI metric and index scores for England (2014-2021) described in the journal paper are provided here as a .csv file to allow exploration of the results: England_FOBI_2014_21.
Please view our FOBI User Guide for further information.
This project is co-funded by Forestry and Land Scotland, Forestry England and Forest Research.
