Research Article Received: 28 December 2016 Revised: 31 May 2017 Accepted article published: 19 July 2017 Published online in Wiley Online Library: 6 September 2017 (wileyonlinelibrary.com) DOI 10.1002/ps.4658 A large-scale assessment of European rabbit damage to agriculture in Spain Miguel Delibes-Mateos,a,b* Miguel Ángel Farfán,c,d Carlos Rouco,e Jesús Olivero,c Ana Luz Márquez,c John E Fa,f Juan Mario Vargasc and Rafael Villafuerteb Abstract BACKGROUND: Numerous small and medium-sized mammal pests cause widespread and economically significant damage to crops all over the globe. However, most research on pest species has focused on accounts of the level of damage. There are fewer studies concentrating on the description of crop damage caused by pests at large geographical scales, or on analysis of the ecological and anthropogenic factors correlated with these observed patterns. We investigated the relationship between agricultural damage by the European rabbit (Oryctolagus cuniculus) and environmental and anthropogenic variables throughout Spain. RESULTS: Rabbit damage was mainly concentrated within the central-southern regions of Spain. We found that rabbit damage increased significantly between the early 2000s and 2013. Greater losses were typical of those areas where farming dominated and natural vegetation was scarce, where main railways and highways were present, and where environmental conditions were generally favourable for rabbit populations to proliferate. CONCLUSION: From our analysis, we suggest that roads and railway lines act as potential corridors along which rabbits can spread. The recent increase in Spain of such infrastructure may explain the rise in rabbit damage reported in this study. Our approach is valuable as a method for assessing drivers of wildlife pest damage at large spatial scales, and can be used to propose methods to reduce human − wildlife conflict. © 2017 Society of Chemical Industry Supporting information may be found in the online version of this article. Keywords: Google search; human − wildlife conflict; landscape change; Oryctolagus cuniculus; pest species; small mammals 1 INTRODUCTION by large numbers of the European rabbit (Oryctolagus cuniculus) Negative impacts of wildlife on humans or their resources have can weaken or kill even persistent leafy crops, and scratching and occurred throughout prehistory and recorded history. Conse- burrowing can degrade pasture still further by encouraging the 5 quences of human − wildlife conflict can be both direct, includ- establishment of weeds. In the UK, rabbit damage was recorded ing disease, injury and death from encounters with dangerous animals, and indirect, such as loss of crops and livestock and damaged infrastructure. Measures for preventing or reducing ∗ Correspondence to: M Delibes-Mateos, Departamento de Biología Vegetal y 1 human − wildlife conflict are increasingly being developed. Suc- Ecología, Facultad de Biología, Universidad de Sevilla, Apartado 1095, 41080, cessful conflict resolution plans are often the result of the assimi- Sevilla, Spain. E-mail: [email protected] lation of proven methods of control or deterrence and their clear adaptation to the nature of the problem at hand.2 The latter a Departamento de Biología Vegetal y Ecología, Facultad de Biología, Universi- dad de Sevilla, Sevilla, Spain requires an accurate assessment of the human − wildlife conflict situation investigated, and a clear understanding of the efficacy, b Instituto de Estudios Sociales Avanzados (CSIC), Córdoba, Spain cost-effectiveness and social acceptability of the methods to be applied. c Departamento de Biología Animal, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain Although human − animal conflict involving large mammals is often highlighted in the media, human livelihoods are arguably d Biogea Consultores, Málaga, Spain much more impacted by small and medium-sized mammals.3,4 These species often cause substantial damage to pastures as e Departamento de Zoología, Campus de Rabanales, Universidad de Córdoba, Córdoba, Spain well as ground and tree crops through grazing or browsing. For example, outbreaks of rodents in apple-growing areas in Germany f Division of Biology and Conservation Ecology, School of Science and the Envi- 111 can cause up to €25 million per year of damage.4 Close grazing ronment, Manchester Metropolitan University, Manchester, UK Pest Manag Sci 2018; 74: 111–119 www.soci.org © 2017 Society of Chemical Industry www.soci.org M Delibes-Mateos et al. as being €115 − 150 million in 1986,6 and around €130 million per 2 MATERIALS AND METHODS year in Australia.7 2.1 Study area Country-wide assessments of the damage caused by rabbits Peninsular Spain covers 493 518 km2 (nearly 85% of the Iberian in the UK and Australia8,9 and by coypu (Myocastor coypus)in Peninsula). The country is divided into 8125 administrative munici- Italy10 have been undertaken. However, analyses of the spatial palities (http://www.ine.es), the territorial units used in the current (where damage happens) and temporal (when damage occurs) analyses. Climate varies widely throughout Spain, with precipi- factors determining the crop damage inflicted by a particular pest tation decreasing eastwards and southwards, and temperature species have been largely missing from large-scale assessments. increasing southwards.22 Mountains border the northern and Such approaches allow for the application of understanding of Mediterranean coasts (maximum altitude 3478 m) but there are what variables may correlate with a species’ propensity to cause also east–west facing ranges in the centre of the Peninsula. damage and thus can permit managers to devise more effective The natural vegetation in the mountains is pine and oak forests measures of control, especially as what may be successful at a and scrubland, but lowlands are mostly dominated by herba- smaller demonstration scale can fail when applied at the broader ceous crops and river terraces, and hill slopes by woody crops 11 landscape level. such as olive. According to the 2010 European Union Farm Struc- Pest outbreaks can be linked to specific environmental condi- ture Survey (FSS), the area under agriculture in Spain was 47% tions. In the case of the Douglas-fir tussock moth (Orgyia pseu- of the whole territory and involved around 9.8% of the eco- dotsugata), eruptions correlated primarily with forest type and nomically active population of the country (http://ec.europa.eu/ 12 climate. However, for some species, particularly insect pests, eurostat/web/agriculture/farm-structure). Arable land dominates transport infrastructure (roads and railway lines) can also per- over woody crops (∼12 × 106 ha versus ∼5 × 106 ha, respectively). 13 mit their dispersal and establishment. There are few studies Cereal crops and olive trees represent just over 50% of arable land on the role of roads and railways as potential corridors along and woody crops, respectively. Fodder crops cover an important which pest species may disperse. An exception is a study of the area of arable land, while fruit trees and vineyards are common brown marmorated stink bug (Halyomorpha halys)intheUSA, woody crops.23 which showed that urban development and railroads facilitated the species’ spread.14 Given the ubiquity of transport infrastruc- ture in many parts of the world, it is likely that pest species will 2.2 Temporal and spatial characterisation of damage reach remote areas as they establish themselves along roads or caused by rabbits railway lines where they can become abundant, and from which We used the Google search engine (www.google.es) and the they can proliferate.15 search terms “pest” and “rabbit” (in Spanish: “plaga” and “conejo”, Assessing crop damage caused by indigenous small mammal respectively) to identify websites containing information on areas pests, as well as increasing our understanding of what determines affected by European rabbits in Spain.24 We selected this word this, is important when the species in question also plays a key combination based on a previous study which showed that this role in a native ecosystem. This is the case for the European rab- permutation, but also “rabbit” and “damage”, worked better than bit in the Iberian Peninsula, its native range.16 The control of the “rabbit” and “crop”, and “rabbit” and “overpopulation”.25 The first rabbit here needs to be effected in such a way that does not cause 600 consecutive sites resulting from our Google search were vis- its unrestrained decline or extinction; this could produce cascad- ited and their content evaluated by M. Delibes-Mateos.24 Searches ing effects in the ecosystem.16 Rabbits in Iberian Mediterranean were performed between 18 May and 11 June 2015. Only websites ecosystems act as a multifunctional keystone species, not only unequivocally containing information on damage caused by the because they are prey for over 30 predators, but also because of European rabbit in Spain were considered valid. These sites mostly their role as an ecosystem engineer.17 By contrast, rabbits cause included media reports on rabbit damage, discussion forums on substantial damage to agriculture in Spain and Portugal,18–20 hunters’ and farmers’ websites, and blogs. Websites that bore no and are regarded as a severe pest species in some regions. relation to rabbit damage in Spain were discarded. Among those Moreover, rabbits are one of the most important small-game ruled out for analyses were websites dealing with pest rabbits in species, hunted in their millions in the two Iberian countries. regions where the species is an invasive alien or advertisements These multiple roles often lead to frequent conflicts between farm- for pet rabbits. We gathered information on the type of agricul- ers, hunters and conservationists regarding how to manage the tural crop damaged by rabbits. As one of our main goals was to species.18 determine areas where rabbit damage occurred, we also docu- Knowing where and when rabbit damage occurs in Spain and mented those municipalities where such damage was reported. which factors may drive it can help mitigate conflicts between the To assess the temporal evolution of the annual online informa- various stakeholders.