How to work out where to focus species conservation

Blog post by Malcolm Burgess, Senior Conservation Scientist, RSPB Centre for Conservation Science.

Conservation resources are limited and need to be used efficiently and where they can be most effective. Always true, but pertinent in times of conservation austerity. Many species we work to conserve and restore are widespread species, albeit declining. Lapwing, Skylark, Swift, Tree sparrow, Marsh tit, Song thrush to name just a few of these declining species in the UK. But we can't always work everywhere in conserving these species, some parts of their range might be more worthwhile to focus work on than other parts. And where to work on a species might depend on the objective - maintaining or increasing range, or breeding numbers, for example.

To help decide where within a species range it is most efficient to undertake work restoring populations there are many tools and frameworks available. Most are used to deciding where to work on groups of species, a 'hotspot' type of approach, such as in the selection of protected areas such as reserves, chosen to represent many species - an efficient use of resources. However single species recovery work within protected areas is only likely to influence relatively small proportions of populations of widespread but declining species, and so landscape–scale interventions, such as those provided through agri-environment schemes, are required.

Widespread but declining species

Many declining species of conservation concern in the UK species are widespread. For these species, deciding where resources are best allocated spatially can be more difficult and becomes very important when, as is often the case, whole-range action is not feasible or affordable. This is a challenge for the RSPB; despite being a large organisation working across the UK (and beyond) it is not usually feasible to trial or implement conservation interventions everywhere.

Many conservation organisations invest in single-species recovery programmes. However, very few formally use spatial conservation prioritization tools to inform resource allocation. In a new paper published in Landscape Ecology this month, we illustrate a relatively simple framework to help guide spatial targeting using pre-existing data from bird atlas's on species abundance and distribution.

A new spatial prioritization framework

Our framework aims to prioritise conservation action for relatively widespread declining bird species by identifying smaller areas to work within to achieve predefined conservation objectives. We first define conservation need for a species by assessing its conservation status along a ‘recovery curve’ - with species moving along the curve as population decline is first understood and then interventions are developed and implemented to bring populations back.

We next defined four species recovery objectives using the species recovery curve , based on species status as measured by population size and range extent. The first objective is to stop ongoing population decline, i.e. maintain current population size. Next is to reverse previous population decline, i.e. increase population size. Once population size is increasing, the objective would be to maintain current range, if this has not been achieved already. The last objective would be to increase range, most obviously (although not necessarily) back into areas previously occupied. We then identify and map potential target areas for species under these objectives, based on spatial and temporal patterns in species abundance using data from the most recent two published bird atlases.

Maps showing the steps of creating priority area maps to maintain population size for Curlew. a) shows relative abundance, b) the spatial cluster analysis results ranked by importance, c) corresponding 10km squares and d) the final targeting map. In our maps we subdivided the UK into 9 areas.

For most species, target areas identified different areas as the highest priority for different conservation objectives. This is important because it suggests that areas selected for conservation intervention by spatial prioritization methods such as ours will in most cases vary according to the conservation objective. These objectives will themselves be influenced by the current trend and status of a species, and both these may change as a species responds to conservation work or falters and fails to make progress.

Our new framework could be applied to birds, or indeed any other taxa, where similar background data exists. Our hope is that this new thinking will help to speed recovery among priority species.

Please contact Malcolm Burgess malcolm.burgess@rspb.org.uk  if you would like a copy of the paper.

Burgess, M., Gregory, R., Wilson, J., Gillings, S., Evans, A., Chisholm, K., Southern, A. & Eaton, M. (2019) Spatial targeting for single species conservation: a framework based on temporal and spatial trends in species abundance and occupancy. Landscape Ecology. https://doi.org/10.1007/s10980-019-00919-3

We wish to thank all the volunteers who contributed considerable time and effort in fieldwork for the two atlases used our analyses. The 1988–1991 Atlas, and Bird Atlas 2007–2011, were both partnerships between BTO, BirdWatch Ireland and the Scottish Ornithologists’ Club.