Biological Correlates of Extinction Risk in Resident Philippine Avifauna

Abstract

The majority of the world’s biodiversity occurs in the tropics, but human actions in these regions have precipitated an extinction crisis due to habitat degradation, overexploitation, and climate change. Understanding which ecological, biogeographical, and life-history traits predict extinction risk is critical for conserving species. The Philippines is a hotspot of biodiversity and endemism, but it is a region that also suffers from an extremely high level of deforestation, habitat degradation, and wildlife exploitation. We investigated the biological correlates of extinction risk based on the IUCN Red List threat status among resident Philippine birds using a broad range of ecological, biogeographical, and life history traits previously identified as correlates of extinction risk in birds. We found strong support across competing models for endemism, narrower elevational ranges, high forest dependency, and larger body size as correlates significantly associated with extinction risk. Additionally, we compared observed threat status with threat status fitted by our model, finding fourteen species that are not currently recognized by the IUCN Red List as threatened that may be more threatened than currently believed and therefore warrant heightened conservation focus, and predicted threat statuses for the four Philippine Data Deficient bird species. We also assessed species described in recent taxonomic splits that are recognized by BirdLife International, finding 12 species that have a fitted threat status more severe than their IUCN-designated ones. Our findings provide a framework for avian conservation efforts to identify birds with specific biological correlates that increase a species’ vulnerability to extinction both in the Philippine Archipelago and elsewhere on other tropical islands.

Priority conservation areas and a global population estimate for the critically endangered Philippine Eagle

“…The population has declined drastically over the past 50 years, mainly due to habitat loss through deforestation (Kennedy, 1977; Bueser et al ., 2003; Panopio et al ., 2021) and persecution (Salvador & Ibanez, 2006; Ibañez et al ., 2016). Thus, the Philippine Eagle fulfils all three components of rarity, and along with its large body size, slow breeding cycle (one young every 2–3 years), and forest dependency would be associated with a higher risk of extinction (Kittelberger et al ., 2021). Despite this elevated extinction risk, fundamental aspects of the species' biology such as distribution and population size are still uncertain (Collar, 1997; Collar, Mallari, & Tabaranza, 1999; BirdLife International, 2018) and need updating using a robust methodology.…”

Priority conservation areas and a global population estimate for the Critically Endangered Philippine Eagle derived from modelled range metrics using remote sensing habitat characteristics

“…The population has declined drastically over the past 50 years, mainly due to habitat loss through deforestation (Kennedy 1977;Bueser et al 2003;Panopio et al 2021) and persecution (Salvador & Ibañez 2006;Ibañez et al 2016). Thus, the Philippine Eagle fulfils all three components of rarity, and along with its large body size and forest dependency would be associated with a higher risk of extinction (Kittelberger et al 2021). Despite this elevated extinction risk, fundamental aspects of the species biology such as distribution and population size are still uncertain (Collar 1997;Collar et al 1999;BirdLife International 2018) and need updating using a robust methodology.…”

“…2016). Thus, the Philippine Eagle fulfils all three components of rarity, and along with its large body size and forest dependency would be associated with a higher risk of extinction (Kittelberger et al . 2021).…”

Hematological and Biochemical Reference Intervals of the Visayan Warty Pig in Negros Occidental, Philippines

“…Possessing extensive biodiversity and endemism, it houses over two-thirds of the Earth's species (2). However, excessive hunting and habitat loss have brought about a staggering decline in the population of endemic wildlife (3,4). While the country is among the few mega-biodiverse countries in the world, it is also one of the top global conservation priority areas with at least 700 threatened species (5).…”