Invasive alien species are a major threat to native insular species. Eradicating invasive mammals from islands is a feasible and proven approach to prevent biodiversity loss. We developed a conceptual framework to identify globally important islands for invasive mammal eradications to prevent imminent extinctions of highly threatened species using biogeographic and technical factors, plus a novel approach to consider socio-political feasibility. We applied this framework using a comprehensive dataset describing the distribution of 1,184 highly threatened native vertebrate species (i.e. those listed as Critically Endangered or Endangered on the IUCN Red List) and 184 non-native mammals on 1,279 islands worldwide. Based on extinction risk, irreplaceability, severity of impact from invasive species, and technical feasibility of eradication, we identified and ranked 292 of the most important islands where eradicating invasive mammals would benefit highly threatened vertebrates. When socio-political feasibility was considered, we identified 169 of these islands where eradication planning or operation could be initiated by 2020 or 2030 and would improve the survival prospects of 9.4% of the Earth’s most highly threatened terrestrial insular vertebrates (111 of 1,184 species). Of these, 107 islands were in 34 countries and territories and could have eradication projects initiated by 2020. Concentrating efforts to eradicate invasive mammals on these 107 islands would benefit 151 populations of 80 highly threatened vertebrates and make a major contribution towards achieving global conservation targets adopted by the world’s nations.
Feeding wildlife is an increasingly popular tourism-related activity despite a limited understanding of potential impacts. Here we demonstrate variable differences in physiological values and endoparasitic infection rates between iguanas from tourist-visited and fed populations versus non-visited populations. The responses from iguanas inhabiting visited islands could compromise health over time.
Modern zoos and aquariums aspire to contribute significantly to biodiversity conservation and research. For example, conservation research is a key accreditation criterion of the Association of Zoos and Aquariums (AZA). However, no studies to date have quantified this contribution. We assessed the research productivity of 228 AZA members using scientific publications indexed in the ISI Web of Science (WoS) database between 1993 and 2013 (inclusive). AZA members published 5175 peer-reviewed manuscripts over this period, with publication output increasing over time. Most publications were in the zoology and veterinary science subject areas, and articles classified as “biodiversity conservation” by WoS averaged 7% of total publications annually. From regression analyses, AZA organizations with larger financial assets generally published more, but research-affiliated mission statements were also associated with increased publication output. A strong publication record indicates expertise and expands scientific knowledge, enhancing organizational credibility. Institutions aspiring for higher research productivity likely require a dedicated research focus and adequate institutional support through research funding and staffing. We recommend future work build on our results by exploring links between zoo and aquarium research productivity and conservation outcomes or uptake.
Oxidative stress is a potential cost of reproduction, but conclusive evidence for this relationship is lacking. The goal of this study was to serially assess across a seasonal gradient the relationship between reproduction, circulating plasma energy metabolites and oxidative state. Here, we examine a study animal ideally suited to test for the oxidative costs of reproduction: the Allen Cays Rock Iguana. Female rock iguanas reproduce at varying frequencies, often skipping years, allowing for a comparison between reproductive and non‐reproductive females during the same narrow, annual breeding season. This feature of iguana life history enabled us to address not just sex and seasonal differences in physiology, but also potential oxidative costs of reproduction in females. Male and female iguanas were sampled during the early (vitellogenic), late (gravid) and post‐reproductive seasons. Ultrasound examinations were performed on females to quantify reproductive investment, and blood samples were collected for physiology assays, which included reactive oxygen metabolites (d‐ROMs), antioxidants, triglycerides, free glycerol and glucose. The early reproductive season was characterized by significant increases in reproductive female's triglycerides, free glycerol and oxidative stress compared to late and post‐reproductive periods and non‐reproductive females and males during all sampling periods. Antioxidants were significantly elevated during the early reproductive season for reproductive females, non‐reproductive females and males when compared to late and post‐season. Follicle number in early reproductive females was positively related to d‐ROMs, triglycerides and free glycerol, negatively related to antioxidants and showed no relationship with glucose. Measures of oxidative stress, d‐ROMs and oxidative index were positively correlated with circulating levels of the lipid metabolite free glycerol during the early reproductive period, but this relationship weakened in the late season and disappeared in the post‐season. Broadly, this study supports the hypothesis that the relationship between reproduction and oxidative stress is driven by energy investment, being greatest during early reproduction when vitellogenesis is occurring.
Intraspecific comparisons among geographically separated populations of wide-ranging species are particularly useful in elucidating variation in behavioral and reproductive life histories resulting from proximate and ultimate causes. From 2001 to 2004, we investigated geographic variation in nesting behavior and reproductive biology of a large-bodied Bahamian iguana ( Cyclura cychlura Cuvier, 1829) inhabiting two distinct island systems varying in area, topography, and rainfall. Studies of C. cychlura cychlura were conducted on Andros Island (approx. 6000 km2; annual rainfall 1100 to 1300 mm) and the results were compared with those for C. cychlura inornata Barbour and Noble, 1916 inhabiting two cays (each <4 ha; annual rainfall <600 mm) in the northern Exuma Island chain (approx. 140 km distant). Female iguanas from Andros Island initiated oviposition 5 to 6 weeks earlier than females from the Exumas. The Andros Island population deposited eggs primarily in termitaria, whereas the lizards in the Exumas deposited eggs in subterranean sand chambers. Female iguanas from Andros deposited significantly more eggs per clutch, heavier total clutches, and wider eggs than conspecifics from the Exumas. Despite egg size differences, hatchling snout–vent length and body mass per clutch did not differ significantly between the Andros and Exuma populations. Our results support the hypothesis that proximate environmental factors play an important role in determining geographic variation associated with not only reproductive output but also reproductive behavior.
The Bahamian Andros iguana (Cyclura cychlura cychlura) is an endangered lizard threatened by habitat loss, illegal hunting, impacts from historic large-scale logging practices and predation by feral animals (e.g. cats, dogs and hogs). There is interest by local and national conservation organisations to demarcate protected areas for the iguana in the southern portion of its range. However, no life history information is available for the lizard. In order to provide data that can be applied in a science-based management strategy for the Andros iguana, we investigated seasonal variation in home-range size and habitat selection of the iguana using radio telemetry. Home ranges were the largest reported to date for free-ranging Cyclura iguanas (Fixed 95% Kernel maximums: 30.58 ha for males, 5.63 ha for females). Habitat selection using the Euclidean Distance method revealed that open pine was the only habitat type out of four where iguanas occurred more than expected by chance. However, the pair-wise comparisons of habitat types reveal that iguanas were found significantly closer to open pine and shrubland than to closed pine. We failed to uncover selection of cumulative home-range placement throughout our multi-habitat study areas. Conservation implications of the dynamic seasonal home-range fluctuations and habitat usage are discussed and recommendations are offered for establishing protected areas.
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