Assessing the effects of different management scenarios on the conservation of small island vulture populations

Abstract

Summary Although the population of Griffon Vulture Gyps fulvus is significantly increasing in Europe, in Italy the species is still on the Red List as ‘Critically Endangered’, with the last natural population persisting on the island of Sardinia. Several episodes of poisoning hampered the success of conservation actions implemented in the years 1987–1995. In 2005 there were estimated to be only 31–32 territorial pairs, with the population occupying the territories of Alghero and Bosa. We used a long-term dataset of reproductive records from the Sardinian Griffon Vulture populations to run a population viability analysis (PVA) to evaluate the extinction risk using the Vortex simulation software. The model estimated the probability of extinction over the next five generations (estimated generation time: 11 years, simulation time used: 55 years) as 96.4% for the Alghero population, and near-zero for the Bosa population. We used sensitivity analyses to understand how uncertainty about parameter values affect model outcomes. Population projections were evaluated under different management scenarios tackling the main threats (poisoning and human disturbance) and implementing conservation actions (supplementary feeding and restocking). Our results showed that population size is a critical factor in affecting the projections of population dynamics of Griffon Vultures. Sensitivity analyses highlighted the importance of poisoning events to population persistence and showed that juvenile and adult mortality rates had a secondary impact on population viability. The only conservation measure effective in significantly increasing stochastic growth rates in the Alghero population, whose initial population was set at five individuals, was the complete removal of poisoning events. When targeting the Bosa population (initial population size 94 individuals), supplementary feeding, mitigation of the risk of poisoning episodes, restocking, and mitigation of human disturbance in the reproductive sites significantly increased stochastic growth rate. A cost-effectiveness analysis should be performed to prioritise interventions.

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

“…61 Strengthening the existing efforts to reduce the prevalence of both deliberate and incidental poisoning, which seems by far the most important mortality cause at least in the MVR population 49 (and this study), will deserve priority in conservation actions endorsing population viability, as also recently outlined for the Sardinian griffon vulture population by Aresu. 18 Even in the case of limited areas interested by poisoning, the effects on survival can be significant, as demonstrated in a population of griffon vultures in Israel reintroduced in two nearby sites (only 70 km apart), one of which was subject to poisoning, where ca. 40% difference in survival for translocated individuals was recorded (Table 2).…”

“…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.…”

Contributions of distemper control and habitat expansion to the Amur leopard viability

“…Population viability analysis (PVA) is a modeling technique for analyzing the dynamics of endangered species 29 , 30 , and helps identifying determinants of population decline for effective management recommendations 31 . Vortex software package has a wide range of applications in PVA, which has been used to evaluate the survival status and different management strategies for the conservation of endangered species, such as the griffon vulture ( Gyps fulvus ), fennec fox ( V. zerda ), and mountain lion ( Puma concolor ) 32 – 34 . In addition, Vortex incorporates inbreeding depression (the organism’s reduced ability to survive as a result of the inbreeding of related individuals), which is very important for small-sized populations like the object of our study.…”

Management Actions Promote Human-Wildlife Coexistence in Highly Anthropized Landscapes: The Case of an Endangered Avian Scavenger

“…Vultures, and particularly Old-World vultures, are by far the most threatened group within them, with 12 of 16 species listed as Endangered or Critically Endangered (McClure et al, 2018;BirdLife International, 2020;McClure and Rolek, 2020). Deliberate or unintentional poisoning events (Plaza et al, 2019;Aresu et al, 2020), conflicts with farmers depending on regional differences of livestock management (Margalida et al, 2014;Duriez et al, 2019), and low survival probability due to accidents with infrastructure, such as electrocution and collision with power lines and wind turbines (e.g., Donázar et al, 2002;Ogada et al, 2016;Badia-Boher et al, 2019;Arrondo et al, 2020) are among the main hazards for this avian group worldwide. Their particular biology and life history (delayed sexual maturity and low productivity, Donázar, 1993), together with the abovementioned threats, caused vulture populations to plummet worldwide (Ogada et al, 2012).…”