Evidence of widespread declines in Kenya's raptor populations over a 40-year period

Ogada, Darcy; Virani, Munir Z.; Thiollay, Jean Marc; Kendall, Corinne J.; Thomsett, Simon; Odino, Martin; Kapila, Shiv; Patel, Teeku; Wairasho, Peter; Dunn, Leah; Shaw, Phil

doi:10.1016/j.biocon.2021.109361

Cited by 11 publications

(11 citation statements)

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“…Twenty percent of raptor species are threatened with extinction (BirdLife International, 2023a), and 52% have declining global populations (McClure et al., 2018). The secretarybird has the greatest EDGE score of raptors and is declining at an exceedingly high rate in Kenya mostly outside of protected areas, perhaps owing to habitat alteration (Ogada et al., 2022). This species is in dire need of major conservation action to reverse that trend.…”

Section: Discussionmentioning

confidence: 99%

Conserving the evolutionary history of birds

McClure

Berkunsky

Buechley

et al. 2023

Conservation Biology

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In the midst of the sixth mass extinction, limited resources are forcing conservationists to prioritize which species and places will receive conservation action. Evolutionary distinctiveness measures the isolation of a species on its phylogenetic tree. Combining a species’ evolutionary distinctiveness with its extinction risk creates a measure called an EDGE score. We use EDGE scores to prioritize the places and species that should be managed to conserve bird evolutionary history. We analyze all birds across species, orders, countries, and important bird areas. We further examine parrots, raptors, and seabirds in depth because these groups are especially threatened and relatively speciose. These three focal groups have greater median threatened evolutionary history than other birds, making them important for conserving bird evolutionary history. Australia, Brazil, Indonesia, Madagascar, New Zealand, and the Philippines are especially critical countries because they have the most threatened evolutionary history for endemic birds and are important for parrots, raptors, or seabirds. We further highlight that increased enforcement of international agreements for the conservation of parrots, raptors, or seabirds is needed because these agreements protect hundreds of millions of years of threatened bird evolutionary history. Decisive action is required to conserve the evolutionary history of birds into the Anthropocene.This article is protected by copyright. All rights reserved

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Section: Discussionmentioning

confidence: 99%

Conserving the evolutionary history of birds

McClure

Berkunsky

Buechley

et al. 2023

Conservation Biology

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“…Here, based on repeated raptor road transect surveys undertaken in four African regions, we examine changes in encounter rates (individuals recorded per 100 km) among 42 species dependent mainly on savanna habitats. To determine rates of change, we combined published and unpublished road transect data from surveys conducted during 1969–1995 and 2000–2020 in West Africa (Burkina Faso, Niger and Mali) 40 , Central Africa (northern Cameroon) 41 , East Africa (Kenya) 42 and southern Africa (northern Botswana) 20 , 43 (Fig. 1 , Supplementary Table 1 and Extended Data Fig.…”

Section: Mainmentioning

confidence: 99%

African savanna raptors show evidence of widespread population collapse and a growing dependence on protected areas

Shaw,

Ogada,

Dunn

et al. 2024

Nat Ecol Evol

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The conversion of natural habitats to farmland is a major cause of biodiversity loss and poses the greatest extinction risk to birds worldwide. Tropical raptors are of particular concern, being relatively slow-breeding apex predators and scavengers, whose disappearance can trigger extensive cascading effects. Many of Africa’s raptors are at considerable risk from habitat conversion, prey-base depletion and persecution, driven principally by human population expansion. Here we describe multiregional trends among 42 African raptor species, 88% of which have declined over a ca. 20–40-yr period, with 69% exceeding the International Union for Conservation of Nature criteria classifying species at risk of extinction. Large raptors had experienced significantly steeper declines than smaller species, and this disparity was more pronounced on unprotected land. Declines were greater in West Africa than elsewhere, and more than twice as severe outside of protected areas (PAs) than within. Worryingly, species suffering the steepest declines had become significantly more dependent on PAs, demonstrating the importance of expanding conservation areas to cover 30% of land by 2030—a key target agreed at the UN Convention on Biological Diversity COP15. Our findings also highlight the significance of a recent African-led proposal to strengthen PA management—initiatives considered fundamental to safeguarding global biodiversity, ecosystem functioning and climate resilience.

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“…We calculated recent ER as birds per 100 km from the last 3 years of study (2019)(2020)(2021) for comparison with other work. ERs for the 3 southern Tanzania NPs were compared with other savannah ecosystems in East Africa based on recent counts from across Kenya (Ogada et al, 2022) and Uganda (Shaw et al, 2019).…”

Section: Transect Analysesmentioning

confidence: 99%

“…As with many species, vulture population trends have been measured primarily over long periods (>20 years). Declines in African vulture populations have been well documented, leading to the uplisting of several species as endangered or critically endangered (Garbett et al., 2018; Ogada et al., 2016, 2022; Thiollay, 2007; Virani et al., 2011). The most significant threat to African vultures is poisoning, and vultures’ tendency to aggregate while feeding makes them particularly susceptible (Ives et al., 2022; Kendall & Virani, 2012; Murn & Botha, 2017; Ogada, 2014, 2015).…”

Section: Introductionmentioning

confidence: 99%

Value of combining transect counts and telemetry data to determine short‐term population trends in a globally threatened species

Kendall

Bracebridge

Lynch

et al. 2023

Conservation Biology

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In order to evaluate conservation interventions, it is necessary to obtain reliable population trends for short (<10 years) time scales. Telemetry can be used to estimate survival rates, and has become a common tool for assessing population trends, but can be limited by high costs, weight and technology constraints that limit duration of function and number of fixes, and can be biased to specific behavioral traits of tagged individuals. Encounter rates calculated from transects can be useful for assessing changes across multiple species, but can have large confidence intervals and can be affected by variation in survey conditions. Declines of African vultures, largely due to poisoning, have been well‐documented over the last several decades, but our understanding of more recent trends is lacking. We used two methods to assess population trends in three protected areas in southern Tanzania over 6–8 years: telemetry data primarily from White‐backed vultures to estimate survival rates, with corresponding estimated population trajectories based on population models, and transect counts for six scavenging raptors. Both methods suggest significant declines for White‐backed vultures in Ruaha and Nyerere National Parks, while only telemetry estimates suggested significant declines in Katavi National Park. Encounter rates calculated from transects also showed declines in Nyerere National Park for Lappet‐faced vultures and Bateleurs and in Ruaha National Park for White‐headed vultures. Mortalities recorded and inferred from telemetry suggest that poisoning is prevalent while highlighting the challenges of determining cause of death when working across large landscapes. Despite these declines, southern Tanzania remains an important stronghold for African vultures with higher current encounter rates than elsewhere in East Africa. However, preventing further declines will heavily depend on the ability to mitigate the threat of poisoning. This study demonstrates the value of using multiple techniques when attempting to understand population trends over short time periods.This article is protected by copyright. All rights reserved

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Evidence of widespread declines in Kenya's raptor populations over a 40-year period

Cited by 11 publications

References 53 publications

Conserving the evolutionary history of birds

Conserving the evolutionary history of birds

African savanna raptors show evidence of widespread population collapse and a growing dependence on protected areas

Value of combining transect counts and telemetry data to determine short‐term population trends in a globally threatened species

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