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Long‐term griffon vulture population dynamics at Gamla Nature Reserve
Author(s) -
Choresh Yael,
Burg David,
Trop Tamar,
Izhaki Ido,
Malkinson Dan
Publication year - 2019
Publication title -
the journal of wildlife management
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.94
H-Index - 111
eISSN - 1937-2817
pISSN - 0022-541X
DOI - 10.1002/jwmg.21566
Subject(s) - vulture , population decline , geography , extinction (optical mineralogy) , wildlife , population , nature reserve , ecology , population growth , biology , demography , habitat , paleontology , sociology
Gamla Nature Reserve (GNR) used to host the largest colony of Eurasian griffon vultures ( Gyps fulvus ) in northern Israel. Since the early 2000s, the colony has suffered a drastic decline, which could lead to its extinction. In this descriptive study we present the population dynamics at GNR based on an analysis of data collected over 15 years (1999–2013). A monitoring scheme of monthly counts, developed at GNR, provided a database, facilitating a mathematical analysis of the population decline trends and their seasonal fluctuations. The analysis revealed a decline in the population size, which appears similar to an inverse‐sigmoid and indicates a potential extinction of the colony by 2020. The analysis also indicates that, in addition to the overall pattern, the number of vultures fluctuates seasonally, with smaller numbers in spring and greater numbers in autumn and winter. Furthermore, this model suggests that latent factors might have influenced the decline; poisoning, thought to be a root cause, might not be the only factor influencing extinction. We demonstrate the importance of combining frequent data collection with modeling techniques for the analysis of raptor population trends. © 2018 The Wildlife Society.