Will creating Stone-curlew habitat benefit rare plants and invertebrates?
With limited conservation funds it is vital to carefully define priorities. In the UK, long-term data on bird population changes provides an excellent basis to objectively define species priorities (e.g. Avery et al. 1995). There are some brilliant examples where investment and prescriptions based on sound evidence have turned around the fortunes of priority species (e.g. Corn Bunting Emberiza calandra (Perkins et al. 2011), Cirl Bunting Emberiza cirlus (Peach et al. 2001), and Corncrake Crex crex (O’Brien et al. 2006)).
Although this approach has worked well for some groups (i.e. birds), conservation often proceeds with a grossly incomplete understanding of regional conservation priorities (Dolman et al. 2012). To address this issue, one possible solution is to use ‘figurehead’ species to help guide ecosystem management (Lambeck 1997). Although this approach is often advocated, the wider taxonomic benefits of managing for figureheads are rarely tested; and when they are, the impact of alternative management strategies are often overlooked (Roberge & Angelstam 2004).
A new partnership project between the RSPB Centre for Conservation Science, the University of East Anglia, Natural England and the Ministry of Defence, is testing whether the Stone-curlew Burhinus oedicnemus, a bird of national conversation concern, presents a suitable conservation figurehead on semi natural grasslands.
Over the past 30 years the RSPB Stone-curlew Recovery Project, a partnership between the RSPB, land managers, farmers, gamekeepers and statutory bodies, has employed a team of field workers to locate all breeding pairs and protect the nests/chicks. The Norfolk and Suffolk Brecks holds a high proportion of UK breeding pairs, where most nest on un-safe habitat where their eggs and chicks are at risk from arable operations. Although the recovery project has been successful (population recovery from about 168 UK pairs in 1991, to a peak of nearly 400 in 2011), ongoing nest protection work is unsustainable and the long-term security of this species depends on more pairs breeding on grassland (Johnston 2009). But the management needed to achieve this has been challenged by others who question whether Stone-curlew management is appropriate for a wider suite of rare species, often neglected in species-focused management.
Characterised by its sandy soils and semi-continental climate, Breckland contains the UK’s largest extent of semi-natural grass heath. Analysis of existing information of species requirements suggests management targeted towards Stone-curlew might potentially benefit up to 453 other regional priority species (Panter et al. 2013). In an effort to realise this biodiversity potential, and test the effectiveness of multi-taxa delivery, we are undertaking one of the largest replicated field experiments ever attempted in the UK. Across the largest area of grass heath remaining in Breckland, 117 experimental ground disturbance plots that differ in establishment technique, size and cultivation frequency have been established (Fig. 1).
Figure 1 Aerial photograph of the experimental treatments on Brettenham Heath NNR. These three plots were created during winter 2014/2015. © Jeff Baker
Conservation evidence suggests that physical disturbance should provide a suitable habitat for nesting Stone-curlew (Green et al. 2000, Green & Griffiths 1994) and a myriad of other regional priorities including many Red-data Book plant and insect species not found elsewhere in the UK (Dolman et al. 2012, Pedley et al. 2012). This approach should also facilitate the spread of rabbit populations, which through a combination of intense grazing and small scale physical disturbance provide an important ecological role on the Breckland grass heaths (Dolman & Sutherland 1992). But the following is unclear:
- Which plots do Stone-curlew prefer for nesting, and does contrasting management create suitable foraging habitats
- Which plots best facilitate the spread of rabbits?
- Which plots are optimal for different taxonomic groups?
- Does the largest biodiversity return coincide with the best techniques for Stone-curlew?
- What other priority species serve as additional or better figureheads?
Over the next four years we will be assessing how Stone-curlew, other priority birds, beetles, true bugs, spiders, flies, ants, and vascular plants, respond to these treatments. Stone-curlew nest sites will be located through regular surveys during the breeding season and GPS loggers will be attached to a sample of birds to track their foraging movements. Other bird species such as Woodlark Lullula arborea will be monitored through targeted surveys and vascular pants and invertebrates will be monitored through quadrat and pitfall trapping, respectively. We will monitor rabbit responses through pellet and burrow counts. Results from this research will inform future conservation efforts on other lowland grassland sites and provide a framework for testing and selecting candidate figurehead species.
Initial findings
In 2015, ground-disturbance plots held six pairs of nesting Stone-curlew (Fig. 2) and 13 pairs of Lapwing Vanellus vanellus, with foraging woodlark and other priority bird species (e.g. Eurasian Curlew Numenius arquata). Invertebrate material from pitfall trapping in June, August and October is still being identified, but to date the 317 species identified include 30 nationally scarce and eight Red Data Book species (seven beetles and an ant) (Fig. 3). This work has been possible thanks to the assistance of several taxonomic experts.
Figure 2 Stone-curlew nests consist of a sallow scrape containing 1-2 eggs. The scrape is excavated during courtship and is often decorated with small stones and/or rabbit droppings. This particular nest was located on one of treatment areas in June 2015 © Peter Feakes
Figure 3 Myrmica karavajevi queen taken from one of the pitfall traps in August 2015. Myrmica karavajevi is a rare (Red Data Book) workerless social ant that parasites two other ant species in Britain (Myrmica scabrinodis and Myrmica sabulet) (Wells 2010) © Doreen Wells
Future work
To understand which treatments are selected for by foraging Stone-curlew, we will track movements of breeding Stone-curlew with GPS trackers during 2016. Avian surveys of plot occupancy and use will continue in 2016 and 2017, and intensive vascular plant and invertebrate monitoring will take place in 2017 (when a full range of treatment age classes will have accumulated).
Find out more about the RSPB’s EU LIFE+ Project – Securing the future of the Stone-curlew in the UK View
References
Avery, M., Gibbons, D.W., Porter, R., Tew, T., Tucker, G. & Williams, G. (1995). Revising the British Red Data List for birds: the biological basis of U.K. conservation priorities. Ibis 137: 232–S239. View
Dolman, P.M., Panter, C.J. & Mossman, H. (2012). The biodiversity audit approach challenges regional priorities and identifies a mismatch in conservation. Journal of Applied Ecology 49: 986-997. View
Dolman, P.M. & Sutherland, W.J. (1992). The Ecological Changes of Breckland Grass Heaths and the Consequences of Management. Journal of Applied Ecology 29: 402-413. View
Green, R.E. & Griffiths, G.H. (1994). Use of preferred nesting habitat by stone curlews Burhinus oedicnemus in relation to vegetation structure. J. Zool. (Lond.) 233: 457-471. View
Green, R.E., Tyler, G.A. & Bowden, C.G.R. (2000). Habitat selection, ranging behaviour and diet of the Stone-curlew (Burhinus oedicnemus) in southern England. J. Zool. (Lond.) 250: 161–183. View
Johnston, A. (2009). Demographic Analysis of the Impact of Conservation Action on Stone-culrew Populations. PhD thesis. Cambridge University.
Lambeck, R.J. (1997). Focal species: a multi-species umbrella for nature conservation. Conservation Biology 11: 849-856. View
O’Brien, M., Green, R.E. & Wilson, J. (2006). Partial recovery of the population of corncrakes Crex crex in Britain, 1993–2004. Bird Study 53: 213–224. View
Panter, C.J., Mossman, H.L. & Dolman, P.M. (2013). Stanford Training Area (STANTA) Biodiversity Audit to Support Grass Heath Management. University of East Anglia, Norwich. View
Peach, W.J., Lovett, L.J., Wotton, S.R. & Jeffs, C. (2001). Countryside stewardship delivers cirl buntings (Emberiza cirlus) in Devon, UK. Biological Conservation 101: 361-373. View
Pedley, S.M., Franco, A.M.A., Pankhurst, T. & Dolman, P.M. (2013). Physical disturbance enhances ecological networks for heathland biota: A multiple taxa experiment. Biological Conservation 160: 173–182. View
Perkins, A.J., Maggs, H.E., Watson, A. & Wilson, J.D. (2011). Adaptive management and targeting of agri-environment schemes does benefit biodiversity: a case study of the corn bunting Emberiza calandra. Journal of Applied Ecology 48: 514–522. View
Roberge, J.M. & Angelstam, P. (2004). Usefulness of the umberalla species concept as a conservation tool. Conservation Biology 18: 76-85. View
Wells, D. (2010). Myrmica karavajevi ((Arnoldi 1930) Formicidae: Myrmicinae) a rare ant new to Norfolk and Suffolk. Trans. Norfolk Norwich Naturalist Society 43 (1)
Image credit
Featured image: Stone-curlew © Chris Knights
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