First assessment of the potential introduction by hunters of eastern cottontail rabbits (Sylvilagus floridanus) in Spain

Abstract

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.

Does prey abundance affect prey size selection by the Eagle Owl (Bubo bubo)?

“…Although no genetic analyses were made to confirm the subspecies, we assume that rabbits from Ossa de Montiel and Ruidera belong to O. c. cuniculus because these localities are within the distribution area of this subspecies described by Geraldes et al (2008). However, in these two study areas, there could be hybrids as they are inside the hybrid zone between O. c. cuniculus and O. c. algirus (Delibes-Mateos et al 2018). Contrary, Los Melonares area was located within the distribution area of the O. c. algirus subspecies, which has a smaller body size (Ferreira et al 2015).…”

To ban or not to ban, is it the only option to regulate biological invasions?

“…En esta línea se han desarrollado, por ejemplo, escaneos de horizonte (del inglés horizon scanning) generales en Gran Bretaña (Roy et al 2014) La inclusión de una EEI en dichas evaluaciones conllevaría automáticamente una prohibición genérica de su uso y tenencia, tal y como hace la legislación actual con las EEIs del Catálogo. En esta categoría se incluirían por ejemplo, especies de acuicultura no presentes en España de forma natural, como la tilapia del Nilo Oreochromis niloticus cuyo uso en instalaciones de acuicultura ha generado presencia ocasional de la especie en ríos adyacentes, convirtiéndose en una amenaza para la biodiversidad acuática (Forneck et al 2021), el alga Acantophora spicifera, considerada como de alto riesgo en el Mediterráneo pero hasta ahora ausente en España (Roy et al 2019) o los conejos americanos del género Sylvilagus introducidos en Italia para la caza (Dori et al 2019) y que se han intentado introducir en diversas ocasiones en España, hasta ahora sin éxito (Delibes-Mateos et al 2018). En esta categoría la gestión debe estar dirigida a la prevención, tratando de minimizar la probabilidad de aparición de las EEIs incluidas en ella en el medio natural.…”

Does the Introduction of Alien Species Represent a Sanitary Threat for Native Species? The Case of the Eastern Cottontail Sylvilagus floridanus in Italy

“…For this reason, after introduction in new areas it can become invasive and quickly expand its range [7], competing with other lagomorphs for space and resources [5]. S. floridanus was Life 2020, 10, 142 2 of 10 introduced for hunting in several European countries during the second half of the 20th century: France (1953), Italy (1966), Spain (1980), and Switzerland (1982) [8,9]. Hunting is an activity supported by the movement, translocation, and introduction of millions of animals.…”