Limited contributions of released animals from zoos to North American conservation translocations/Introduction

by Typhenn A. Brichieri-Colombi, Natasha A. Lloyd, Jana M. McPherson, Axel Moehrenschlager

Introduction

In an effort to curb the growing loss of biodiversity, conservation translocations, “the intentional movement and release of a living organism where the primary objective is a conservation benefit” (IUCN SSC 2013), have become an increasingly important form of species management (Seddon et al. 2007; Bajomi et al. 2010; Brichieri-Colombi & Moehrenschlager 2016; Swan et al. 2016). It is unclear how many conservation translocations are performed annually worldwide, but recent reviews indicate that over 1200 species have been subject to conservation translocations to date, based on data on North American animals (Brichieri-Colombi & Moehrenschlager 2016), global marine taxa (Swan et al. 2016), plants (Godefroid et al. 2011; Liu et al. 2015), birds (Lincoln Park Zoo 2008; Cromarty & Alderson 2013), mammals (Van Houtan et al. 2009), amphibians (Short 2009), invertebrates and reptiles (McHalick 1999), and additional global conservation translocation databases (Soorae 2008, 2010, 2011, 2013; Armstrong et al. 2015; Soorae 2016). Conservation translocations are an important tool for addressing global conservation concerns and should be conducted responsibly when their needs and use are justified (IUCN SSC 2013).

Conservation translocations inevitably require a viable source population. Preferences are generally given to wild populations due to relatively high post-release success in terms of survival, behavior or breeding performance across species (Letty et al. 2007). However, declines in abundance, extent of occurrence, area of occupancy or connectivity may render remaining populations too fragile to act as a continuous source (Dimond & Armstrong 2007; Todd & Lintermans 2015).

The obvious alternative to wild source populations is captive breeding. Captive breeding can be difficult due to taxon-specific genetic, behavioral, or health challenges and postrelease success is often limited unless animals are specifically selected or adequately prepared for release (Todd & Lintermans 2015). Conversely, captive breeding can be advantageous given the ability to provide assurance against species extinction (Zippel et al. 2011), and an increased ability to target specific sex or age cohorts for releases (IUCN SSC 2013).

Institutions with long-standing experience in captive breeding or ex situ propagation include zoos and aquaria (hereafter jointly referred to as zoos). For example, the Bronx zoo was involved in the first bison (Bison bison) translocation in 1907 (Kleiman 1989). Conservationminded breeding emerged in the 1960s (Carr & Cohen 2011) and by the 1980s transformed into the Ark paradigm, which focused on safeguarding genetic reservoirs for species or subspecies whose wild populations are under threat from human impacts (Lees & Wilcken 2009). Today, many genetically representative assurance populations are held under human care (Conde et al. 2011). However, assurance populations can only help stem the loss of biodiversity and functional ecosystems if safeguarded genes or species are ultimately returned to the wild. Accordingly, many modern zoos have in recent years increased focus on and allocated resources for threatened species recovery (Penning et al. 2009; Barongi et al. 2015), and at least two zoo associations, the World Association of Zoos and Aquariums (WAZA) and the European Associations of Zoos and Aquaria (EAZA), have formally adopted the International Union for Conservation of Nature’s (IUCN) Guidelines for Reintroductions and Other Conservation Translocations (IUCN SSC 2013; Barongi et al. 2015; EAZA 2018). Species that have benefited from releases to the wild include the Arabian oryx (Oryx leucoryx), golden lion tamarin (Leontopithecus rosalia), California condor (Gymnogyps californianus), Kihansi spray toad (Nectophrynoides aspergini), Mauritius kestrel (Falco punctatus), Black Robin (Petroica traversi), and black-footed ferret (Mustela nigripes), which would all be extinct without zoo intervention.

Nonetheless, it remains unclear how relevant captive breeding programs in zoos have been or could be to conservation translocations in general. A global but dated review by Beck et al. (1994) showed zoos contributed to 59% of 129 reintroduction projects involving captive bred individuals. More recently, a review based on the Global Re-introduction Perspectives (GRP) case study series (Soorae 2008, 2010, 2011, 2013, 2016) published by the IUCN Reintroduction Specialist Group indicated that zoos were involved in only 35% of conservation translocations and contributed captive-bred individuals for release into the wild in only 20% of cases (Gilbert et al. 2017). We wondered whether such trends are representative in general and indicative of North American activities. North America is one of the world regions with the highest conservation translocation activity globally (Seddon et al. 2014), and North American zoos accredited by the Association of Zoos and Aquaria (AZA) annually spend on average US$160 million on conservation initiatives (AZA 2018), almost half of the US$350 million raised annually for conservation by zoo and aquarium associations around the world (Conde et al. 2011; Barongi et al. 2015).

Although the GRP case studies are a valuable resource, they stem from invited submissions and are not intended as an unbiased or systematic data set of conservation translocations generally. For example, although at least 279 animals species have undergone conservation translocations in North America (Brichieri-Colombi & Moehrenschlager 2016), GRP case studies have been published for only 48 (17%) of these. To expand understanding of the role of captive breeding and specifically of zoos in conservation translocations, we therefore mined less-biased data gleaned from a comprehensive literature review of animal conservation translocations in North America, including Canada, the United States, Mexico, Central America, and the Caribbean (Brichieri-Colombi & Moehrenschlager 2016). We used these data to examine what proportion of North American animal conservation translocations involve captive-bred source populations, and of these, what percentage come from zoos. Moreover, we asked to what extent zoo professionals actively contribute to the science of conservation translocations by reporting their insights and experiences in peer-reviewed journals. As animal-care specialists, educators, communicators, wildlife advocates, and scientists, zoo professionals have a diversity of skills to help advance the effectiveness of conservation translocations (Barongi et al. 2015), but few zoos have traditionally seen systematic research and publication as a priority (Griffith et al. 1989; Carr & Cohen 2011).