Sound science or social hook: a response to Brooker's application of the focal species approach

Brooker [Landscape and Urban Planning, in press] recently published a worked example of the focal species approach using bird assemblages in fragmented landscapes of western Australia. We have some concerns about the scientific validity of the focal species approach. As a threat-based biodiversity surrogate scheme, the focal species approach is likely to suffer from similar deficiencies that have been identified for related forms of species-based surrogate schemes such as umbrella species and indicator species approaches. We also raise concerns that the responses of birds, which are the sole group for which the focal species approach has been applied, may not be good species-based indicators of the responses of other vertebrates (such as reptiles, amphibians and mammals) for which selected focal species purport to be a surrogate. There are also non-trivial issues regarding field sampling intensity and patch or fragment size and the potential to underestimate the conservation value of small remnants during applications of the focal species approach. Despite these scientific concerns, we nevertheless consider that the focal species approach may be an important social hook to stimulate restoration activities in degraded landscapes that are now increasingly common not only in Australia, but also in many other parts of the world. However, we make a plea for the development of additional approaches for the restoration of degraded landscapes and that these methods (as well as the focal species approach) be subject to rigorous field testing.