Nonparametric spatial regression of survival probability: visualization of population sinks in Eurasian woodcock.

Both evolutionary ecologists and wildlife managers make inference based on how fitness and demography vary in space. Spatial variation in survival can be difficult to assess in the wild because (1) multisite study designs are not well suited to populations that are continuously distributed across a large area and (2) available statistical models accounting for detectability less than 1.0 do not easily cope with geographical coordinates. Here we use penalized splines within a Bayesian state-space modeling framework to estimate and visualize survival probability in two dimensions. The approach is flexible in that no parametric form for the relationship between survival and coordinates need be specified a priori. To illustrate our method, we study a game species, the Eurasian Woodcock Scolopax rusticola, based on band recovery data (5000 individuals) collected over a > 50 000-km2 area in west-central France with contrasted habitats and hunting pressures. We find that spatial variation in survival probability matches an index of hunting pressure and creates a mosaic of population sources and sinks. Such analyses could provide guidance concerning the spatial management of hunting intensity or could be used to identify pathways of spatial variation in fitness, for example, to study adaptation to changing landscape and climate.

Vaccination of free-living juvenile wild rabbits (Oryctolagus cuniculus) against myxomatosis improved their survival.

For several decades, the populations of the European wild rabbit (Oryctolagus cuniculus) have declined, which is partly due to myxomatosis. Vaccination against this disease is expected to contribute to restoration of rabbit populations but the actual impact of myxomatosis is not well known and vaccination might have some negative effects. We analyzed the capture-mark-recapture data obtained in a 4-year field experiment (1991-1994) in a park near Paris, France wherein 300 out of 565 seronegative juvenile rabbits were vaccinated at first capture against myxomatosis with the nontransmissible Dervaximyxo SG33 vaccine. After accounting for weight at first capture, age-class (juvenile/adult), "trap-happiness" and season (spring/autumn) of the capture event, vaccinated rabbits had 1.8-fold greater odds of surviving than the unvaccinated rabbits. The average summer survival risk for vaccinated juveniles was 0.63 (+/-0.08 S.E.) whereas it was 0.48 (+/-0.08 S.E.) for unvaccinated juvenile rabbits.