Studies connecting microbiome composition and functional performance in wildlife have received little attention and understanding their connections with wildlife physical condition are sorely needed. We studied the variation in gut microbiota (hard fecal pellets) between allopatric subspecies of the European wild rabbit in wild populations and in captured individuals studied under captivity. We evaluated the influence of environmental and host‐specific factors. The microbiome of wild
rabbit populations reduced its heterogeneity under controlled conditions. None of the host‐specific factors tested correlated with the microbiota composition. We only observed significant intra‐group dispersion for the age factor. The most diverse microbiomes were rich in Ruminococcaceae potentially holding an enriched functional profile with dominance of cellulases and xylanases, and suggesting higher efficiency in the digestion of fiber‐rich food. Conversely, low diversity gut microbiomes showed dominance of Enterobacteriaceae potentially rich in amylases. We preliminary noticed geographical variations in field populations with higher dominance of Ruminococcaceae in south‐western than in north‐eastern Spain. Spatial differences appeared not to be subspecies driven, since they were lost
in captivity, but environmentally driven, although differences in social structure and behavior may also play a role that deserve further investigations. A marginally significant relationship between
the Ruminococcaceae/Enterobacteriaceae ratio and potential life expectancy was observed in captive rabbits. We hypothesize that the gut microbiome may determine the efficiency of feeding resource exploitation, and can also be a potential proxy for life expectancy, with potential applications for the management of declining wild herbivorous populations. Such hypotheses remain to be explored in the future.

Accurate methods for age determination are critical to the knowledge of wildlife populations’ age structure and, therefore, to their successful management. The reliability of age estimation may have profound economic and ecological consequences on the management of the European wild rabbits, Oryctolagus cuniculus, in its native and introduced range, where it is a keystone species and a major pest, respectively. As in other mammal species, European rabbits’ age is often estimated using the Gompertz relationship between age and lens’ weight. The growth rate formula has been developed based on data collected from European rabbits introduced in Australia, where a single subspecies (O. cuniculus cuniculus, Occ) is present. However, this curve has never been validated in the species native range, the Iberian Peninsula, where two subspecies (Occ, and O. c. algirus, Oca) coexist naturally. In this study, we tested the relationship between age and lens’ weight using 173 Occ and 112 Oca wild rabbits that were surveyed in two experimental facilities in Spain. Our findings show that, in the native range, the published growth curve formula fits well Occ but not Oca data. Therefore, we recommend using the formula reported in this study to estimate the age of Oca (Lens dry weight = 240 × 10(−64.9/ (Age+32))). This study supports Oca rabbits’ distinctiveness revealed by previous studies, which suggests that management interventions should be applied to protect this subspecies whose distribution range is very narrow and whose populations seem to be declining. More broadly, our findings point to the importance of testing the suitability of growth curves defined for other species with different genetic forms as occurs in the European wild rabbit case.

Aim of study: Monitoring and control the hunting activity is primordial to guarantee its sustainability. However, the governmental agencies responsible to manage hunting commonly are unable to adequately do this job because the thousands of small private hunting states, associated exclusively by political-administrative criteria. In this work, we provided a new management tool through the establishment of a hunting regions system.
Area of study: Castilla-La Mancha region, central Spain.
Material and methods: We used a two-stage procedure to establish the environmental units than, afterwards, were characterized on a set of hunting variables.
Main results: We generate a hunting regionalization with 12 hunting regions and proposed regional hunting yields for each of the hunting regions.
Research highlights: The use of hunting regions will permit to define the game management practices more appropriately on a large scale, but also, will facilitate the tasks of assessment, management and monitoring of game of the number hunting states included in each hunting region.

In many parts of the world, millions of wildlife species are hunted for sport, food, skins, and other products. In recent years, a backlash has emerged from certain groups of society against this long-standing human pursuit. However, attitudes towards the control of wild animals to reduce the health risk to other animals, to lessen agricultural damage, or to protect game species, may generate a different reaction, where even killing is tolerated. In this paper, we analyze the public’s acceptance of control hunting in Andalusia (southern Spain). Our results suggest that lethal control to improve domestic animal health is highly accepted (75%) is more controversial when animals are killed for damaging crops (59% acceptance) and is highly unaccepted when the goal is to enhance game species numbers (22% acceptance). Older people and males, in particular, accept more readily some of these control-hunting measures. These results are needed to understand better the public attitudes on which conservation managers can base their decisions when control hunting is required.

Widespread generalist predators may affect declining keystone prey populations. However, this phenomenon is not well understood. In this paper, we assessed whether the abundance and population growth of European rabbits Oryctolagus cuniculus, a keystone prey species in Mediterranean Iberia, was related to the abundance and diet of red foxes, Vulpes vulpes, a widespread generalist predator. In a locality in central Spain, where rabbit population abundance declined, we estimated rabbit abundance during almost 3 years and determined fox abundance and diet during two concurrent years. We calculated a fox predation index (percentage of consumed rabbit biomass × fox abundance) to assess the importance of rabbits to foxes. We employed a multi–model approach to explain rabbit abundance and population growth. Foxes consumed between 60 and 99 % rabbit biomass in their diets, and this was independent of rabbit abundance. Periods of higher fox predation index coincided with lower rabbit density and vice versa. Two models best explained rabbit abundance and four rabbit population growth. They included the fox predation index and its interaction with rabbit abundance during the previous month. Altogether, fox predation, intraspecific density dependence, and their interaction partly explained rabbit population dynamics. We conclude that in order to propel the recovery of the rabbit in Iberia, it is essential to better understand the role of these factors in driving the abundance of the species., This is a partial result from the I+D National Plan Projects CGL2005-02340, CGL2009-10741 and CGL2013-43197, funded by the Spanish Ministry of Science and Innovation and EU FEDER funds. JFdS benefitted from a FPI PhD scholarship (BES-
2006-12562) funded by the Spanish Ministry of Science and Innovation and the European Social Fund. J. Fernandez-de-Simon and F. Díaz-Ruiz are currently holding a postdoctoral fellowship from Junta de Castilla-La Mancha and the European Social Fund (Operational Programme FSE 2007/2013). M. Delibes-Mateos is currently funded
by Junta de Andalucía and the EU FP7, under grant agreement 267226., Peer Reviewed

How foraging behaviour of predators is influenced by prey abundance is often not clear. Predators may behave as generalist or specialist depending on the relationship between the predator feeding behaviour and prey abundance, known as functional response. The European rabbit (Oryctolagus cuniculus) is a key species for most Iberian vertebrate predators, especially for large raptors such as the eagle owl (Bubo bubo). The eagle owl functional response was analysed in central Iberian Peninsula by fitting different models (null, linear, two asymptotic and two sigmoidal models) between rabbit abundance and rabbit consumption by the eagle owl. Rabbit consumption increased as did its abundance until reaching an asymptote. Rabbit-consumed biomass better fitted to a type II functional response (convex, typical of specialist predators), whereas rabbit frequency in eagle owl diet better fitted to a type III functional response (sigmoidal, typical of generalist predators). Trophic diversity increased as rabbit abundance decreased. The consumption of other prey, such as Iberian hare (Lepus granatensis) and medium-size birds (mainly galliformes and columbiformes), increased as rabbit abundance decreased. The eagle owl is highly dependent on rabbits in central Spain, even at low rabbit abundance. In this situation, the eagle owl diversifies its diet, making it difficult to define the eagle owl as a specialist or as a generalist predator. Therefore, the eagle owl in the centre of the Iberian Peninsula should be rather considered as a facultative predator on wild rabbits., This study is a partial result of CGL2005–02340, CGL2009–10741, and CGL2013-43197 projects, from I+D National Plan funded by the Spanish Ministry of Science and Innovation and EU–FEDER funds. J. Fernandez-de-Simon benefitted from a FPI PhD scholarship (BES–2006–12562) funded by the Spanish Ministry of Science and Innovation and the European Social Fund. J. Fernandez-de-Simon and F. Diaz-Ruiz are currently holding a postdoctoral fellowship from Junta de Castilla-La Mancha and the European Social Fund (Operational Programme FSE 2007/2013)., Peer Reviewed

Cost-effective indices to estimate relative abundances of species are crucial for their management and conservation. As an example, population indices are needed to monitor extensive breeding nuclei used for translocating wild rabbit populations. Based on counts of faecal pellets from four high density rabbit nuclei in southwest Spain: (i) we assess the accuracy of this population index in high-density populations; and (ii) present a simulation approach to evaluate how the reduction of the counting effort affects accuracy of the population estimates. Our findings suggest that this method provides a valid estimate in high-density rabbit populations, and, notably, estimates would have not substantially changed after a reduction of 45–65% in the number of counted plots depending on variation on rabbit density between nuclei. We provide a framework that managers and other scientists could use to improve data collection of pellet counts in order to optimize their chances of detecting relative abundance estimates of rabbits. In addition, we present a R function to implement our approach that can easily be applied in a variety of monitoring programmes for other species based on count data. This will likely help to reduce field-effort in different studies without compromising population indices estimates., Funding was provided by Confederación Hidrográfica del Guadalquivir and research project CGL2013-43197. C. Rouco and M. Delibes-Mateos are supported by the Talentia Postdoc Program launched by the Andalusian Knowledge Agency, co-funded by the European Union's Seventh Framework Program, the Marie Skłodowska-Curie actions (COFUND–Grant Agreement n° 291780 and 267226, respectively), and the Ministry of Economy, Innovation, Science and Employment of the Junta de Andalucía., Peer Reviewed

Myxomatosis is a viral disease that affects European rabbits (Oryctolagus cuniculus) worldwide. In Spain, populations of wild rabbits drastically decreased in the 1950s after the first outbreak of myxomatosis. Since that first appearance, it seems to be an annual epizootic in Spain with periodic outbreaks, predominantly in summer and autumn. Taking into account rabbit population structure, abundance, and genetic lineage, this paper attempts to make a large-scale characterization of myxomatosis seroprevalence based on the immune status of 29 rabbit populations distributed throughout Spain, where O. cuniculus cuniculus and O. c. algirus, the two known rabbit subspecies, naturally inhabit. A total of 654 samples were collected between 2003 and 2009, and seroprevalence of antibodies against Myxoma virus (MYXV) was determined. Overall, our results revealed that 53% of the rabbit samples were positive to antibodies against MYXV. Newborn and juvenile rabbits were the most susceptible animals to the virus, with 19% and 16% seropositivity for newborn and juveniles, respectively, while adult rabbits were the most protected, with 65% of seropositive samples. This suggests that prevalence is negatively related to the proportion of newborn and juvenile rabbits in a population. Our results also showed that seroprevalence against MYXV tended to be higher in high-abundance populations. In contrast, no differences were detected in seroprevalence between rabbit subspecies. This study confirms that > 60 years since first outbreak, myxomatosis is an endemic disease in Spain. Based on the results, the establishment of a myxomatosis surveillance protocol is proposed., C. Rouco is supported by the Talent Hub Program launched by the Andalusian Knowledge Agency, co-funded by the European Union Seventh Framework Program, the Marie Skłodowska-Curie Actions (COFUND–Grant Agreement no. 291780), and the Ministry of Economy, Innovation, Science and Employment, Government of Andalucía. M. Delibes-Mateos is supported by V Plan Propio de Investigación of the University of Sevilla. Special thanks to P. Ferreras, C. Ferreira, I. Barrio, F. Aparicio, L.E. Mínguez and C. Iriarte for support during field work. Funding was provided by the projects PEII 09-0097-4363, FAU2006-00014-C02-02, and CGL2013-43197-R all cofounded by EUFEDER funds., Peer Reviewed

Speciation is a process proceeding from weak to complete reproductive isolation. In this continuum, naturally hybridizing taxa provide a promising avenue for revealing the genetic changes associated with the incipient stages of speciation. To identify such changes between two subspecies of rabbits that display partial reproductive isolation, we studied patterns of allele frequency change across their hybrid zone using whole-genome sequencing. To connect levels and patterns of genetic differentiation with phenotypic manifestations of subfertility in hybrid rabbits, we further investigated patterns of gene expression in testis. Geographic cline analysis revealed 253 regions characterized by steep changes in allele frequency across their natural region of contact. This catalog of regions is likely to be enriched for loci implicated in reproductive barriers and yielded several insights into the evolution of hybrid dysfunction in rabbits: (i) incomplete reproductive isolation is likely governed by the effects of many loci, (ii) protein–protein interaction analysis suggest that genes within these loci interact more than expected by chance, (iii) regulatory variation is likely the primary driver of incompatibilities, and (iv) large chromosomal rearrangements appear not to be a major mechanism underlying incompatibilities or promoting isolation in the face of gene flow. We detected extensive misregulation of gene expression in testis of hybrid males, but not a statistical overrepresentation of differentially expressed genes in candidate regions. Our results also did not support an X chromosome-wide disruption of expression as observed in mice and cats, suggesting variation in the mechanistic basis of hybrid male reduced fertility among mammals., The work was supported by POPH-QREN funds from the European Social Fund and Portuguese MCTES [FCT Investigator (IF/00283/2014/CP1256/CT0012) and postdoc grant to MC (SFRH/BPD/72343/2010); postdoc grants to JAB-A (SFRH/BPD/65464/2009) and SJS (SFRH/BPD/99138/2013)]; by the ERC project BATESON to LA; by FEDER funds through the COMPETE programme and Portuguese national funds through the FCT (projects PTDC/CVT/122943/2010 and PTDC/BIA/EVF/111368/2009); by the projects“Genomics and Evolutionary Biology” and “Genomics Applied to Genetic Resources” cofinanced by North Portugal Regional Operational Programme 2007/2013 (ON.2—O Novo Norte) under the National Strategic Reference Framework (NSRF) and the European Regional Development Fund (ERDF), by I+D National Plan Project CGL2013-43197-R financed by the Spanish Ministry of Economy and Competitiveness, by an EU FP7 REGPOT grant [CIBIO-New-Gen] [286431] and by travel grants to MC (COST Action TD1101)., Peer Reviewed

[Aim of study]: Monitoring and control the hunting activity is primordial to guarantee its sustainability. However, the governmental agencies responsible to manage hunting commonly are unable to adequately do this job because the thousands of small private hunting states, associated exclusively by political-administrative criteria. In this work, we provided a new management tool through the establishment of a hunting regions system. [Area of study]: Castilla-La Mancha region, central Spain. [Material and methods]: We used a two-stage procedure to establish the environmental units than, afterwards, were characterized on a set of hunting variables. [Main results]: We generate a hunting regionalization with 12 hunting regions and proposed regional hunting yields for each of the hunting regions. [Research highlights]: The use of hunting regions will permit to define the game management practices more appropriately on a large scale, but also, will facilitate the tasks of assessment, management and monitoring of game of the number hunting states included in each hunting region., Funding was provided by project CGL2013-43197-R, cofounded by EUFEDER funds; National Council on Science and Technology of Mexico, CONACyT (doctoral grant to CARS)., Peer Reviewed

[Context]: Humans have introduced lagomorph species in areas outside their native ranges for their meat, fur or value as game species. Assessing the rate of success of lagomorph introductions is vital to address the ecological damage they may cause. Cases of failed lagomorph introductions in apparently suitable areas may also shed light on mechanisms that may deter invasion, which are useful in developing strategies for population control. In Spain, it has been suggested that hunters introduced the non-native eastern cottontail (Sylvilagus floridanus) to compensate for the recent drastic declines of the native European rabbit (Oryctolagus cuniculus). [Aims]: Our main goals were to investigate (1) whether Sylvilagus rabbits have indeed been introduced by hunters across Spain, and (2) whether the species has become established in Spanish ecosystems. [Methods]: We interviewed 311 hunters or naturalists across Spain. The questionnaires inquired about the characteristics of game management in each locality, including the frequency of rabbit restocking, and particularly whether Sylvilagus rabbits had been released in the surveyed localities. In addition, we sampled 192 rabbit populations (n = 3974 individuals) across Spain by using molecular analysis to determine whether Sylvilagus rabbits were present in these areas. [Key results]: Our interview results suggest that Sylvilagus rabbits may have been released in 6% of the 311 localities surveyed. However, molecular analyses failed to confirm their persistence, because all samples belonged to O. cuniculus. [Conclusions]: We infer that Sylvilagus rabbits failed to establish themselves in Spain, although interviewees reported their introduction. Several reasons may explain the unsuccessful establishment of this species, such as a low propagule pressure, competition with native species, predation, inability to cope with local pathogens and unsuitable climatic conditions. [Implications]: The risk of future introductions of non-native game species can be reduced through the implementation of stricter regulations of animal releases into the wild. Long-term monitoring networks should be developed to help identify non-native game species before they become established and spread to neighbouring areas, thereby preventing any ecological or economic impacts these species may cause., This study was partially financed with the projects ‘Diagnosis of the effects of rabbit populations on crops in Catalonia’ and ‘Genetic characterisation of the rabbit populations in Valencia’, funded by Forestal Catalana and Vaersa. S.A., respectively, and the projects PAI06-170, VP-0119-07, POII09-0099-2557, CGL2009-11665, 2012-30E060, and CGL2013-43197-R. M. Delibes-Mateos was supported by V Plan Propio de Investigación of the Universidad de Sevilla. C. Campos Ferreira is supported by a Marie Curie Outgoing International Fellowship for Career Development (PIOF-GA-2013-621571) within the 7th Framework Program of the European Union. C. Rouco was also supported by XXII Propio de Investigación of the
University of Córdoba and ‘Programa Operativo de fondos FEDER Andalucía’., Peer Reviewed

The recreational use of natural resources requires the implementation of sustainable management systems. However, the existence of socioeconomic interests and the difficulty involved in applying evidence-based criteria often hinder this implementation. The European wild rabbit (Oryctolagus cuniculus) is an appropriate case with which to study the recreational hunting governance systems. This species has, in recent decades, undergone important population changes in its native area, the Iberian Peninsula, where it plays a triple role as a game, pest and key ecological species. The rabbit is consequently intensively managed for hunting purposes, for the conservation of rabbit-dependent predators and in order to mitigate damage to crops. In this paper, we study the governance system of rabbit hunting through the use of questionnaire surveys distributed to managers working for Spanish regional governments. We repeated the survey in 2001 and 2016 in order to evaluate how the system had evolved over a 15-year period of important changes in rabbit population abundance. We found two different responses to these changes. The growth of rabbit populations in provinces in which rabbits cause crop damage in farmland areas has been dealt with an increase in hunting pressure, derived from both administrative decisions and hunters’ management. However, in provinces where rabbit populations have sharply declined in natural vegetation (non-farmland) areas, the management seems to be driven mostly by inertia, with a high influence of tradition and little use of evidence on administrative decisions. Hunters in these provinces have changed their management practices to little or no extent, where even the high importance of rabbit hunting and its (moderate) economic importance do not appear to provide an incentive for the change required., This study is a contribution of the CGL2013-43197-R project (I + D National Plan), funded by the Spanish Ministry of Science and Innovation.