Throughout the world, vultures are faced with severe population declines and local extinctions due to the extensive use of poisoned baits. In addition to this deadly threat, a reduction in food availability due to the decline of extensive farming and the introduction of strict carcass disposal legislation further suppresses their survival chances. Thankfully, conservationists have a variety of tools that guide them in developing and delivering targeted conservation actions to achieve the greatest possible outcomes for the survival of a species population. One such tool is Population Viability Analysis (PVA), a method of risk assessment used in conservation biology to determine the probability of a population going extinct within a given number of years. One such analysis was recently undertaken by the Vulture Conservation Foundation (VCF) as part of the LIFE with Vultures project to determine how the Cyprus Griffon Vulture population might change over the years. The results confirm the urgency of the task at hand: saving the Griffon Vulture in Cyprus.
PVA paves the way for conserving Cyprus vultures
The analysis has shown that if no management and conservation actions are taken with the currently small population size (20 individuals), the Griffon Vulture in Cyprus could go extinct within just 15 years, largely due to the frequency of poisoning incidents, which – as things stand – can probably occur four times once every five years. These poisoning events do not only increase mortality rates, but they also reduce reproductive rates as breeding or chick-rearing activities are disrupted. The analysis has shown that to boost the rate of population growth in order to reach the long-term target number of individuals (200) within 35 years two things need to happen: a planned population supplementation strategy of releasing at least 24 individuals over a two-year period in combination with eliminating poisoning. This combined management approach would allow the population to reach 45 individuals within 4 years, which is also a target of the LIFE with Vultures project. Encouragingly, the analysis predicts that the population could reach the medium-term target of 100 individuals in less than 20 years. Eliminating poisoning without reinforcing the population with releases of more vultures would prevent the extinction of the population, but it would take more than 55 years for it to reach close to the long-term target of 200 individuals.
In short, the PVA confirms that to help the population to recover, poisoning needs to be eliminated or, as a minimum requirement, the frequency of poisoning incidents needs to be reduced to less than one poisoning incident every 10 years. In addition, to ensure the species’ long-term survival in Cyprus, we also need to reinforce the current population with individuals brought from elsewhere, reduce mortality through provision of safe food and minimize disturbance at breeding sites in order to reach the best possible reproductive output. Therefore, a suite of targeted conservation actions working in synergy will be required.
How does PVA work?
Using specialized population modelling software, the Vulture Conservation Foundation created a baseline scenario and simulated the fate of the Cypriot population under the current conditions using a combination of published and observational data of many years such as records of survival, reproductive success, the current population size, number of deaths, the maximum number that can be reached within a particular timeframe on the island, and more. Using knowledge of the main threats to the Cyprus Griffon Vulture population and based on the conservation interventions foreseen by the LIFE with Vultures project, different management scenarios were created such as the import and release of extra individuals, and the reduction of catastrophic events such as the frequency and severity of poisoning incidents. In this way, PVAs can point out the most important actions that need to be made in order to decrease the extinction risk for a species population, and help scientists to prioritize conservation actions based on which one of these would have the greatest positive effects against extinction.
The importance of EU LIFE-funded projects for the conservation of vultures
Since the 1950s, the Griffon Vulture in Cyprus is being threatened by mass poisoning incidents and by a significant reduction of available food. The fact that it is also an isolated population, meaning that no natural addition of new individuals from other populations occurs (no immigration) makes it even more vulnerable. Efforts to save the species on the island through conservation actions have been ongoing since 1987 and are currently continuing thanks to the EU funded “LIFE with Vultures” project.
The population of the Griffon Vulture in Cyprus shares a similar history with the one in Sardinia, the last stronghold of the species in the whole of Italy. Currently, surviving in two distinctive areas of the island; Bosa and Alghero, the combined population used to number between 800-1,200 individuals in the late 1940s, while ended up with only 31-32 breeding pairs by 2005. Conservation efforts and management strategies to safeguard the Sardinian Griffon population via provision of supplementary food and the import of new vultures between 1987 and 1995 were hindered by mass poisoning incidents that occurred in 1997, 1998, and 2006. Scientists under the “LIFE under Griffon Wings” project employed a PVA to assess how the population size of the species in Sardinia may change over the years based on various estimates and to prioritize conservation actions based on the identified urgent needs of the species. For the larger Bosa vulture population which also receives immigrants from the smaller Alghero population, a significant increase could be achieved through a mixture of management approaches, including the mitigation of the risk of poisoning incidents. Contrastingly, for the smaller and isolated Alghero population no management tactics would significantly change the rate in which it increases over time, apart from the complete removal of poisoning incidents. The VCF supported the LIFE Under Griffon Wings project, securing and transporting 65 Griffon Vultures from Spain for their eventual release in Sardinia.
The results from this PVA are congruent with the findings from the PVA done for the Griffon Vultures in Cyprus, which highlights how important it is to minimize the occurrence of poisoning incidents at low frequency and severity for other conservation actions to have positive effects.
LIFE with Vultures
LIFE with Vultures is a targeted conservation project for the protection of the Griffon Vulture in Cyprus. In this four-year endeavor (2019-2023), BirdLife Cyprus, the Game and Fauna Service, Terra Cypria – The Cyprus Conservation Foundation and the Vulture Conservation Foundation have joined forces to tackle the main threats facing the Griffon Vulture and prevent Cyprus’ most threatened bird of prey from going extinct. The project has a 1,375,861 Euro budget and is co-funded (60%) by the EU’s LIFE programme.
This article was adapted from a previous blog published by BirdLife Cyprus.