Integrating effects of supplementary feeding, poisoning, pollutant ingestion and wind farms of two vulture species in Spain using a population viability analysis

Abstract

Population viability analyses (PVAs) are a useful technique in risk-assessment studies aimed at determining which demographic parameters are most influential in population persistence. Here, we incorporate demographic and environmental stochasticity in the construction of individual-based models integrating the effects of different scenarios in a PVA of the Eurasian Griffon Vulture (Gyps fulvus) and the endangered Egyptian Vulture (Neophron percnopterus) in Spain. Scenarios were based on reasonable options of population management, including effects of supplementary feeding (decreasing mortality and increasing fecundity), extensive wind farm development (increasing mortality), and catastrophic events such as poisoning (decreasing fecundity and survival) or pollutant ingestion (decreasing fecundity but no effect on survival). Our results show that those measures affecting survival show higher negative effects on population growth rate than those affecting fecundity. The outcomes were different and highly depend on the initial conditions and the species considered, with stronger negative effects on Egyptian Vulture populations. For both species, under similar conditions, the effects of massive poisoning, even occurring at low time frequency, had stronger negative consequences in population trends than the pollutant accumulation, or other actions affecting survival, such as installation of wind farms. Measures aimed at improving survival and fecundity such as supplementary feeding at vulture restaurants give rise to positive population trends. The establishment of management actions aimed at improving the birds' survival and increasing breeding success will probably boost the scavengers' populations into an upward trend, which is particularly important in the case of the endangered Egyptian Vulture. Keywords Elasticity analysis Á Gyps fulvus Á Neophron percnopterus Á PVA Á Vortex software Zusammenfassung Population Viability Analysis (PVA) ist eine nützliche Methode in Risikobewertungsstudien, die darauf abzielt, zu ermitteln, welche demographischen Parameter für das Fortbestehen von Populationen am einflussreichsten sind. Hier berücksichtigen wir demographische Stochastizität und Umweltstochastizität bei der Konstruktion individuenbasierter Modelle, welche die Effekte verschiedener Szenarien in eine PVA für den Gänsegeier (Gyps fulvus) und den stark gefährdeten Schmutzgeier (Neophron percnopterus) in Spanien integrieren. Die Szenarien beruhen auf angemessenen Optionen von Populationsmanagement, welche die Effekte von Zufüttern (erniedrigt die Mortalität und erhöht die Fruchtbarkeit), großflächigem Bau von Windenergieparks (erhöht die Mortalität) und katastrophalen Ereignissen wie Vergiftung (erniedrigt die Fruchtbarkeit und das Communicated by F. Bairlein. Electronic supplementary material The online version of this article (Ü berleben) oder Schadstoffaufnahme (erniedrigt die Fruchtbarkeit, aber hat keinen Effekt auf das Ü berleben) einschließen. Unsere Ergebnisse zeigen, dass diejenigen Maße, die das Ü berleben be...

Relative contribution of local demography and immigration in the recovery of a geographically-isolated population of the endangered Egyptian vulture

“…In Europe, population decline has been putatively attributed to mortality induced by poisoning and electrocution (García-Ripollés and López-López, 2011) and to the reduction in pastoralism and the setting up of sanitary regulations that have reduced the availability of carcasses in the wild (Margalida et al, 2010;Martínez-Abraín et al, 2012). The south-eastern French population of Egyptian vultures suffered from a steep decline in numbers of pairs (from~100 in 1900 to 12 in 2000, Orabi, 2008) Avizanda et al, 2010).…”

“…The Egyptian vulture is a medium-sized and long-lived raptor characterized by a late onset of reproduction and a high elasticity of population growth rate to adult survival (García-Ripollés and López-López, 2011;Grande et al, 2009). French Egyptian vultures winter in the Sahel region between Mauritania and Senegal (Meyburg et al, 2004).…”

Rescue of a small declining population of Spanish imperial eagles

“…Analyses of population viability as a tool to evaluate management techniques have been used extensively (Nilsson, 2003;Naujokaitis-Lewis et al, 2008;Soutullo et al, 2008;Duca et al, 2009;García-Ripollés and Lopéz-Lopéz, 2011). Here we used the Vortex simulation software (Vortex, version 9.72;Lacy et al, 2005) to compare variation in persistence time before and after the application of the recovery plan, including two scenarios, with and without releases of young eagles by hacking.…”

Ranging Behaviour of Non-Breeding Eurasian Griffon VulturesGyps fulvus: A GPS-Telemetry Study

“…The species is globally and regionally catalogued as "Least Concern" (Del Moral 2009, BirdLife International 2011. Habitat loss, rural abandonment, intensification of farming practices, and rising of non-natural mortality caused by poisoning (Gangoso et al 2009), pollutant ingestion (Hernández & Margalida 2008, Lemus et al 2008) and collision with wind-farms (Tellería 2009, Martínez-Abraín et al 2012, are the main threats to vulture populations (García-Ripollés & López-López 2011).…”