Survival of translocated wild rabbits: importance of habitat, physiological and immune condition

Abstract

European wild rabbit populations are declining in Mediterranean ecosystems, where the species is of special conservation interest, and translocations are one of the most-used tools to recover populations. We evaluated the effects of habitat and physiological and immune condition on the short-and long-term survival of translocated adult wild rabbits. Rabbits were released in four different habitat treatments frequently used in conservation programmes: additional shelter, additional food, additional shelter plus food, predator exclusion and control. Before releasing the rabbits, we determined their physiological condition from body-mass and serum levels of urea, creatinine and total protein, and their immune condition from the concentrations of antibodies against myxomatosis and rabbit haemorrhagic disease. The risk of dying during the first 18 days post-release was two times lower in the predator exclusion treatment than that in the additional shelter, food, shelter plus food treatments and control. Short-term survival was also negative and positively correlated with creatinine and protein levels, respectively. The risk of dying from 19 to 180 days post-release in the additional food treatment was 10 and nine times lower than in predator exclusion and control, respectively, and negatively correlated with the antibody concentration against myxomatosis. The results suggest that short-term survival was related to predation risk and physiological condition, and long-term survival was related to food availability and myxomatosis incidence. We recommend that translocation programmes should consider using soft-release methods to reduce the risk of predation and ensure that all individuals are released in the best possible physiological condition to increase their short-term survival. We also suggest that the habitat be managed to ensure that the environment provides the appropriate conditions (i.e. food and shelter) for individuals and population persistence. Immune condition should be taken into account and translocation programmes should consider the origin of donor populations to reduce the variability of pathogen and virus strains.

Changes in social groups across reintroductions and effects on post‐release survival

“…a larger sample size) warrants further investigation, particularly considering that post-release survival was high for this reintroduction (by comparison, previously Panfylova et al (2016) reported just 19% female survival 6 months post-release). Social effects could then be incorporated with evidence for other individual-level effects on survival (Goldenberg et al, 2019), such as exploratory tendency or boldness (Bremner-Harrison, Prodohl & Elwood, 2004;May, Page & Fleming, 2016;Germano et al, 2017;Richardson et al, 2019), or physiological condition (Adams et al, 2010;Cabezas, Calvete & Moreno, 2011) to help inform conservation strategies and select individuals with the best suite of characteristics that might predict a successful translocation (see Parlato & Armstrong, 2013).…”

European wild rabbit (Oryctolagus cuniculus) restocking: Effects on abundance and spatial distribution

“…Our results did not properly achieve the second of our goals—to study the potential for releasing rabbits in subterranean tube warrens as a method for achieving successful restocking. According to the restocking results, we might consider those shelters as useful, but as only one of many influential factors in these dynamics (Cabezas et al ). The second goal might be achieved using indexes such as warren activity (Fernández‐Olalla et al ).…”

“…We carried out a variety of different types of actions in each estate, including pasture improvement using phosphorus fertilizers in the areas surrounding the restocking zones (50 ha in each estate; Cabezas et al ), as described in Table . The restocking using subterranean tube warrens focused on creating areas of high wild rabbit density and good habitat (Calvete ).…”

High rabbit abundance proves detrimental to the population growth rate in European rabbit (Oryctolagus cuniculus L.) extensive breeding enclosures

“…In these 9 enclosures, the rabbits were released in autumn and provided with the same kind of food ad libitum. The number of rabbits released was corrected by a short-term mortality rate of 66% estimated in adjacent predator exclusion fences (Guerrero-Casado et al, 2013b), similar to those estimated in other translocation exclusion fences (Cabezas et al, 2011). The number of rabbits/ha could be calculated as (adjusted R²=0.73; F(1,8)…”