Invasive species and Pacific island bird conservation: a selective review of recent research featuring case studies of Swinhoe’s storm petrel and the Okinawa and Guam rail

Abstract

Nowhere are the negative impacts of invasive species, such as ecosystem modification, predation, parasitism, and disease, more apparent than in the Pacific islands, where human contact triggered a massive avian extinction event that is still ongoing. Island bird species are inherently vulnerable to extinction due to their small, isolated populations and lack of evolved defenses against many predators. To prevent further extinctions, effective bird conservation strategies must be implemented to mitigate invasive species' impacts, which often interact synergistically and collectively comprise some of the greatest threats to global biodiversity. At the 2014 International Ornithological Congress in Tokyo, Japan, researchers convened a symposium to address research and management of invasive species to benefit Pacific island bird conservation. Speakers presented research and conservation efforts from Japan, Korea, Guam, the Galápagos, and New Zealand, highlighting novel, poorly known threats to birds (e.g., mortality from invasive plant entanglement and invasive nest parasites) and providing updates on ongoing efforts to prevent island endemic species extinctions driven by invasive predators. In this paper we provide new details of research and conservation efforts on Swinhoe's storm petrel (Oceanodroma monhris), the Okinawa rail (Gallirallus okinawae), and the Guam rail (G. owstoni), and put this research in context by briefly reviewing and synthesizing other relevant, recent studies on impacts of invasive species as they affect Pacific island bird conservation. We conclude by highlighting successful management strategies, recommending improvements for ongoing conservation efforts, and suggesting directions for future research.

Long-distance translocations to create a second millerbird population and reduce extinction risk

“…Owing to their evolution in isolation, island species are vulnerable to threats posed by introduced plants, animals, and pathogens; habitat loss also is a significant threat (Fleischer and McIntosh, 2001;Pratt, 2009;Seabrook-Davison and Brunton, 2011). As a result, the vast majority of bird extinctions have occurred on islands, and the species that persist often do so in dwindling numbers and in diminished range (Moors, 1985;Pratt, 2009;Arcilla et al, 2015). Creating additional, wild populations in high-quality habitat can contribute to the recovery of endangered island species, or at minimum provide a buffer against extinction while threats are addressed (Ewen et al, 2012).…”

Prevalence of antimicrobial‐resistant Escherichia coli in endangered Okinawa rail (Gallirallus okinawae) inhabiting areas around a livestock farm

“…The Okinawa rail ( Gallirallus okinawae ) is a flightless bird in the family Rallidae and the species inhabit the evergreen laurel forest zone, called “Yambaru,” located in the northern part of Okinawa Main Island, Japan (Figure ). Wild populations of the Okinawa rail are declining because of habitat loss and predation by invasive alien species such as the small Indian mongoose ( Herpestes auropunctatus ), feral cats ( Felis catus ) and feral dogs ( Canis lupus ) (Arcilla, Choi, Ozaki, & Lepczyk, ; Harato & Ozaki, ; Yamada & Sugimura, ). The Okinawa rail is currently listed as an endangered species in The International Union for Conservation of Nature Red List (IUCN, ) and highly protected under Act on Conservation of Endangered Species of Wild Fauna and Flora and Programs for the Rehabilitation of Natural Habitats and Maintenance of Viable Populations of Japan.…”

“…The Okinawa rail (Gallirallus okinawae) is a flightless bird in the family Rallidae and the species inhabit the evergreen laurel forest zone, called "Yambaru," located in the northern part of Okinawa Main Island, Japan (Figure 1). Wild populations of the Okinawa rail are declining because of habitat loss and predation by invasive alien species such as the small Indian mongoose (Herpestes auropunctatus), feral cats (Felis catus) and feral dogs (Canis lupus) (Arcilla, Choi, Ozaki, & Lepczyk, 2015;Harato & Ozaki, 1993;Yamada & Sugimura, 2004).…”

Community Engagement with Wildlife Conservation in Japan: A Case Study of an Endangered Bird, the Okinawa Rail (Hypotaenidia okinawae)

“…Yanbaru also has a high incidence of threatened species, including four critically endangered mammal and bird species (Itō et al 2000;Japanese Red Data Search System 2016a). Island species that have restricted distributions and experience evolutionary development in isolation are particularly prone to population decline as they have reduced capacity to respond to introduced predators and human activities (Arcilla et al 2015). Okinawa is no exception, where there has been a documented spread of feral domestic animals and introduced predators throughout threatened species' habitats, and where at least 77 km 2 of natural forest was lost to agricultural and urban development between the 1970s and early 2000s (Government of Japan 2014).…”

“…Predation by feral cats, dogs and introduced species, particularly the Javan mongoose (Herpestes javanicus), has also had signifi cant impact on the population (Yanbaru Wildlife Conservation Center 2015b; Ozaki et al 2006). Predation is the primary cause of an observed northward contraction in the range of the Yanbaru Kuina, which contributed to an estimated 40% reduction in the species' total distribution from the late 1980s to 2004 (BirdLife International 2017; Ozaki et al 2006;Arcilla et al 2015). Other signifi cant causes of mortality include vehicle collisions, particularly during the active breeding season, when Yanbaru Kuina dash across roads between forest patches, accounting for 70% of recorded deaths in one study conducted between 1998 and 2003 (Kotaka and Sawashi 2004).…”