In this post Andrea Santangeli discusses his recent paper ‘Identifying effective actions to guide volunteer-based and nationwide conservation efforts for a ground-nesting farmland bird

Countless conservation actions are implemented by local practitioners worldwide with the intention to help target species to persist in landscapes under increasing pressure from human activities. Unfortunately, still very few implemented interventions are evaluated for their effectiveness (Ferraro & Pattanayak 2006). However, in recent years there has been some progress in this field, and as more evaluations are performed, it becomes clear that sometimes well-intentioned actions may even be counterproductive in their biological outcomes. This fact alone should provide a huge motivation towards scanning for solutions, applying alternative interventions, and then monitoring and evaluating effectiveness (Sutherland et al. 2014).

Production regimes in agricultural systems have seen a rapid intensification in recent decades, with increased mechanization, use of chemical inputs as well as anticipated practices such as harvesting and mowing. Farmland birds are paying a high toll from such recent changes (Donald, Green & Heath 2001). In a recently published study, Santangeli et al. evaluate the effectiveness of a series of interventions to protect nests of the Montagu’s harrier (Circus pygargus), a ground-nesting raptor that nowadays mainly breeds on farmland within western Europe. Across France, an army of trained citizen volunteers implemented protection measures for this species’ nests and carried out monitoring for multiple years. This massive effort yielded the large amount of data necessary to statistically disentangle the different factors affecting nesting productivity and consequently the effectiveness of protection.

A nest protected with a fenced buffer, one of the most effective interventions identified. The fence is visible among the standing crop retained around the nest, while the rest of the field was harvested (left picture). The Montagu’s harrier nestlings (right picture) remain within the fence until they are ready to fledge (Pictures courtesy of Santangeli, A).
A nest protected with a fenced buffer, one of the most effective interventions identified. The fence is visible among the standing crop retained around the nest, while the rest of the field was harvested (left picture). The Montagu’s harrier nestlings (right picture) remain within the fence until they are ready to fledge (Pictures courtesy of Santangeli, A).

The implemented interventions involved protection from harvesting alone (e.g. through the retention of a small buffer of un-harvested crop around the nest, relocation of the nest, or marking the nest with a flag), or protection from harvesting and predation (which included the addition of a fence around the nest with an un-harvested crop buffer or around a relocated nest). One of the most interesting outcomes of the study revolves around the synergistic impact of nest destruction due to mechanical harvesting and predation on the relative effectiveness of interventions. When a nest was protected only from mechanical harvesting (e.g. with a buffer, the most commonly implemented intervention across France), it avoided mechanical destruction during harvesting. However, after the field was harvested, the retained nest was left as an easily detectable feature on or near bare ground. Predation at these nests was severe, to a level that it generally counterbalanced most of the positive impacts derived from protection from harvesting. Therefore, currently a large fraction of citizen conservation efforts could go wasted if predation is not considered.

On the positive side, applying a fence (aimed to protect from predation) around a nest is cheap and fast, but its biological benefits are tremendous. Coupling harvest protection with a fence to protect from predation resulted as the most effective intervention. Now that we know what works and what doesn’t, how can we find out where in France are the best chances to increase the species productivity, and how these areas compare with the current citizens’ efforts? The authors show in a map that there are large and distinct areas where protection efforts could provide a disproportionately high benefit to the species but where citizens’ efforts are underrepresented. The practical implications of these findings for Montagu’s harrier protection in France are clear: 1) interventions need to consider protection from harvesting and predation (with a fence) simultaneously in order to be effective and 2) some areas across France hold more potential for benefiting the species through volunteers’ actions than other areas. A next step is thus to inform conservation citizens about the most effective measures to apply, and where to concentrate more efforts.

Literature cited

Donald, P.F., Green, R.E. & Heath, M.F. (2001) Agricultural intensification and the collapse of Europe’s farmland bird populations. Proceedings of the Royal Society of London Series B-Biological Sciences, 268, 25-29.

Ferraro, P.J. & Pattanayak, S.K. (2006) Money for nothing? A call for empirical evaluation of biodiversity conservation investments. Plos Biology, 4, 482-488.

Sutherland, W.J., Gardner, T., Bogich, T.L., Bradbury, R.B., Clothier, B., Jonsson, M., Kapos, V., Lane, S.N., Möller, I., Schroeder, M., Spalding, M., Spencer, T., White, P.C.L. & Dicks, L.V. (2014) Solution scanning as a key policy tool: identifying management interventions to help maintain and enhance regulating ecosystem services. Ecology and Society, 19.

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