Condatis bottlenecks spatial data for broad habitat networks in England

Condatis bottlenecks spatial data identifies priority areas for habitat creation and restoration to increase habitat connectivity across England, for four broad habitat types: deciduous woodlands, seminatural grasslands, heathlands and wetlands. The Condatis decision support tool was used to identify the geographical location and extent of 'bottleneck areas’, i.e. large gaps between habitat patches that may impede the movement of species through landscapes, affecting their ability to respond to environmental changes, such as climate change. These areas can help inform the prioritisation of sites for habitat restoration or creation for the different habitats. The Nature Recovery Network (NRN) commitment by the UK Government aims to restore and link up natural habitats to support nature’s recovery. The data presented here can be used to inform conservation planning to support the delivery of the national NRN and county-level Local Nature Recovery Strategies (the latter are required under the UK’s Environment Act 2021 (c 30)). By improving ecological connectivity, the NRN will be more resilient and coherent, and ultimately support greater biodiversity. The underlying broad habitats were classified from the Natural England Priority Habitats Inventory version 3.0 (PHI), and thus include seminatural habitats of conservation priority according to national legislation. Bottleneck areas were identified at two spatial scales: national and regional, with the latter derived by combining several Local Nature Recovery Strategy areas (LNRS areas). Condatis models species' movement from a chosen initial location in the landscape - the source, to a final location - the target. To consider a range of possible courses of movement through the landscape, we set sources and targets according to each main compass direction: south-north, east-west, southeast-northwest, and southwest-northeast. We set modelled dispersal distances based on the literature assembled by Travers (2022) to represent UK species. The national-scale analysis used a moderate-high dispersal ability of 3.4 km, and the regional analyses used the median (2 km) or moderate-low (1 km) dispersal. The main spatial data outputs are the [1] ‘Bottleneck areas’ polygons, which are most relevant for planning habitat restoration and creation to improve connectivity, representing zones where additional habitat would be most impactful, if on-ground factors permit. Additionally, supplementary files to aid in interpreting and querying the bottleneck areas are available: [2] Broad habitat input data (rasters of the four broad habitats from the Natural England PHI); [3] Regions (polygons of the eight regions of England which were used for the regional analysis, created by dissolving several Local Nature Recovery Strategy areas); [4] Sources and Targets (classified polygons allowing re-creation of the sources and targets we used in both national and regional analyses; these were based on buffering the boundaries of the LNRS areas); [5] Bottleneck lines (the lines representing ‘difficult jumps’ that species have to make between habitat patches, from which the more simplified bottleneck areas polygons are derived). This archive also contains [6] National Flow raster data for the four broad habitats - a side product of the above data analyses that was used for a different project. We recommend that practitioners use the bottleneck area polygons to refine ‘search areas’ during habitat restoration and creation planning. However, since our estimation is based only on the distribution of underlying habitat patches and species movement, it cannot inform on feasibility in terms of underlying geology, existing land-use or obstructions in the bottleneck area. It is essential, therefore, to use these bottleneck maps in conjunction with other relevant spatial information to identify sites where habitat restoration or creation is feasible. Full documentation is available in the accompanying user guides: Bottlenecks_data_user_guide.pdf and National_flow_user_guide.pdf. Use these data in accordance with the Open Government License (https://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/). Use the attribution statement Hodgson et al 2024.