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In Europe, bromadiolone, an anticoagulant rodenticide authorized for plant protection, may be applied intensively in fields to control rodents. The high level of poisoning of wildlife that follows such treatments over large areas has been frequently reported. In France, bromadiolone has been used to control water voles (Arvicola terrestris) since the 1980s. Both regulation and practices of rodent control have evolved during the last 15 years to restrict the quantity of poisoned bait used by farmers. This has led to a drastic reduction of the number of cases of poisoned wildlife reported by the French surveillance network SAGIR. During the autumn and winter 2011, favorable weather conditions and high vole densities led to the staging of several hundreds of Red Kites (Milvus milvus) in the Puy-de-Dome department (central France). At the same time, intensive treatments with bromadiolone were performed in this area. Although no misuse has been mentioned by the authorities following controls, 28 Red Kites and 16 Common Buzzards (Buteo buteo) were found dead during surveys in November and December 2011. For all these birds, poisoning by bromadiolone as the main cause of death was either confirmed or highly suspected. Other observations suggest a possible impact of bromadiolone on the breeding population of Red Kites in this area during the spring 2011. French regulation of vole control for plant protection is currently under revision, and we believe this event calls for more sustainable management of rodent outbreaks. Based on large-scale experiments undertaken in eastern France, we propose that direct control of voles at low density (with trapping or limited chemical treatments) and mechanical destruction of vole tunnels, mole control, landscape management, and predator fostering be included in future regulation because such practices could help resolve conservation and agricultural issues.

This study investigates the effect of land use, and landscape composition and structure on the population dynamics of fossorial water vole (Arvicola terrestris scherman Shaw). Water vole populations were monitored from 1989 to 1994 in the Doubs department, France, by using index methods. Land use patterns were studied based on agriculture and forestry data from the French Ministry of Agriculture collected in 1956, 1970, 1979 and 1988. Grassland quality and landscape structure were studied based on field transects, combined with the assessment of landscape structure from maps at 1:25,000 scale. Outbreaks of water vole populations occurred as a wave, spreading from epicentres over more than 2500 km2. The propagation speed was in excess of 10 km/yr. On a regional level (n × 10 km) and over 5 years and more, density variation patterns of water vole were linked to the ratio of ploughed land and of permanent grassland to farmland. At a sectional scale (n × 1 km), forests and uncultivated lands had a dampening effect both on the outbreaks and on their duration. The evolution of farmlands from 1956 to 1988 was apparently the major cause of increase in density variations of water vole. Therefore, land use and landscape management could be a way to control water vole outbreaks, and their effects are discussed.

International audience; Travelling waves (TW) are among the most striking ecological phenomena emerging in oscillating populations. Despite much theory, understanding how real-world TW arise remains a challenge for ecology. Herein, we analyse 16-year time series of cyclic vole populations collected at 314 localities covering 2500 km² in France. We found evidence for a linear front TW spreading at a speed of 7.4 km year(-1) along a north-west/south-east direction and radiating away from a major landscape discontinuity as predicted by recent theory. The spatial signature of vole dispersal was assessed using genetic data collected at 14 localities. Both data sets were handled using similar autocorrelation approaches. Our results revealed a remarkable congruence of the spatial extent and direction of anisotropy of both demographic and genetic structures. Our results constitute the first empirical evidence that effective dispersal is limited in the direction of TW while most of the individual exchanges occur along the wave front.

International audience; Pest control is a global issue for agriculture, health, biodiversity conservation and economy. Anticoagulant rodenticides are used over large areas to control rodent pests and can cause widespread poisoning of nontarget wildlife. In France, bromadiolone is the only pesticide authorized to control the water vole Arvicola terrestris Scherman, in grasslands. Since 2001, legislation has been in place to replace curative treatments by preventive ones and limit the quantity of rodenticide used. As the legislation took effect over time, the impact on red fox Vulpes vulpes populations was monitored. Fox populations and bromadiolone treatments were monitored in the Doubs Department (5000 km² area), France. Fox counts were carried out during spring, and vole control was primarily conducted in autumn. Relative fox densities (Kilometric Abundance Index: KAI) obtained per commune for year n (2004-2009) were related to treatments achieved during year n−1 (2003-2008). Treatments from year n−2 were used to investigate possible delayed responses in fox populations. Kilometric Abundance Index of foxes was significantly related to treatment intensities in years n−1 and n−2. The impact was greatest in a large area (>1000 km²), where intensive treatments were achieved in 2003. Fox KAI generally remained dramatically low in this area until 2005, after which a partial recovery was observed. The same area was treated again from 2006 to 2008 but with only half the amount of bait per hectare that was used in 2003. These treatments were followed by a moderate decrease in fox populations. Synthesis and applications: We have established, for the first time on a regional scale, the negative impact of a rodenticide on fox populations. We have shown that a shift to preventive treatments with reduced anticoagulant rodenticide use is less harmful to fox populations. However, to approach a zero impact, treatments should be reduced further by limitation of bait quantities authorized per hectare and per commune and using alternative methods to chemical control. Long-term monitoring of wildlife populations using index methods can provide valuable information about the adverse effects of pesticides; therefore, we recommend their inclusion in the assessment of pest management practices.

Various observed patterns of common vole ( Microtus arvalis ) population kinetics have been classified into five types according to two criteria: the time period of changes in abundance (season or year) and the presence or absence of local extinction. Some types may be subdivided into categories depending on the duration of population fluctuations. They can be ordinate along a gradient correlated to the importance of permanent grassland in farmland and we suggest that this correlation is mainly due to the fact that a major predator ( Mustela nivalis ) can use grassy landscape elements as refuges and easily disrupt population kinetics from low abundance and smooth variations to large amplitude cycles with pullulation periods. Thus major shifts in land use patterns towards a dominance of grassland can enhance the abundance of a pest species such as the common vole. Local extinctions and recolonization as observed in type IV are characteristics of metapopulation. Further field data of local vole populations will be very useful in the development of predictive models.