Modelling the effect of environmental variables on the reproductive success of Griffon Vulture (Gyps fulvus) in Sardinia, Italy

Abstract

Old World vultures are experiencing dramatic population declines and now are among the species most threatened with extinction. Understanding the environmental variables that can influence the reproductive indexes of vulture populations can facilitate both habitat and species management. The aim of this study was to identify which environmental variables primarily affect the breeding successes of the Griffon Vulture Gyps fulvus in northern Sardinia by applying a Bayesian hierarchical model. A unique dataset of reproductive records (197 nests monitored over 39 years for a total of 992 breeding records) was used. Eight environmental and topographical variables describing the habitat at the nesting sites were considered as potential predictors of breeding success. These included mean annual temperature, mean annual precipitation, isothermality, elevation, the normalized difference vegetation index, wind speed, and the aspect and slope of the land surface. In addition, we also considered the effect of human disturbance and the type of nest. According to our best model, the probability of successfully raising a chick in Griffon Vultures was higher in nests exposed to a high wind speed, not covered by natural shelters, where the vegetation was mostly represented by shrub and pastures, with low human disturbance and in years with low rainfall. This model will be useful for management of the breeding habitat and to identify the area most suitable for Griffon Vulture reproduction. This information is crucial for programming conservation measures aimed at enlarging the area of occupancy of the species.

Survival of a small reintroduced griffon vulture population in the Apennines: Insights from Global Positioning System tracking

“…To date, few studies are available to adequately support the management of this species, planning effective conservation strategies over the medium-long term. [18][19][20] To contribute filling such gap, in the framework of a long-term conservation project for the Eurasian griffon vulture populations of the central and southern Apennine (Italy), twenty vultures have been captured and fitted with Global Positioning System (GPS) tags in Pollino National Park (PNP, Basilicata and Calabria regions) and Monte Velino Reserve (MVR, Abruzzi region), with the aim of studying movement ecology and population parameters. More specifically, here we report the first information on estimated survival rate and related mortality causes from telemetry data for this small, reintroduced, griffon vulture population of the centralsouthern Apennines.…”

Insights on the best release strategy from post-release movements and mortality patterns in an avian scavenger

“…47 This initiative, coupled with anti-poisoning campaigns and supplementary feeding, aimed to counteract the prolonged decline of the population in the island, caused by multiple mass mortality events and declining extensive livestock, 48 which had decreased the number of reproductive pairs since the 1980s. 49 …”

Griffon Vultures restrict movements around roosts and supplementary feeding stations, even when carrion is available on the field: a call for wind energy zonation to avoid ecological traps on Mediterranean islands

“…In this study we aim at i) quantifying space use and ii) its overlap with existing wind farms and iii) assessing how the presence of supplementary feeding stations, altogether with landscape and topographic attributes, affect resource use by restocked griffons in Sardinia, a Mediterranean island with the only autochthonous population of griffons in Italy [22] [23] . Finally, in the light of our findings we will provide realistic recommendations on the deployment of wind turbines in the flight zone of a griffon vulture colony.…”