ORCID Profile
0000-0003-0655-3549
Current Organisation
University of Adelaide
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Publisher: CSIRO Publishing
Date: 10-09-2021
DOI: 10.1071/WR20162
Abstract: Abstract Context The koala (Phascolarctos cinereus) sometimes occurs as an overabundant folivore in south-eastern Australia, where high-density populations have caused defoliation of preferred food trees, threatening habitat. Kangaroo Island, South Australia and Budj Bim National Park, Victoria, are two regions where such eruptive population dynamics have arisen. One way of mitigating their damage is through management via fertility control. Aims This paper examines the outcomes of fertility control (surgical sterilisation and treatment with levonorgestrel implants) on breeding dynamics at the population level, using data obtained from two separate koala management programs conducted by State Government wildlife agencies, South Australia Department for Environment and Water and Parks Victoria. Methods The relationships between female body condition, reproductive status, fertility control, age and population density were examined using linear mixed effects models. Population density (koalas/ha) was estimated using annual census data and modelled in a Bayesian framework. Key results Body condition was a key influence on breeding success in female koalas, with sexual maturity being defined by both age and body condition, whereas the effect of reproductive experience was minimal. It is likely that reduced densities have led to decreased intraspecific competition for food resources and territory, leading to increased breeding success at one management site (BBNP) and by allowing females to begin breeding at a lower overall body condition. The reduction in densities to sustainable levels at both management sites, despite differing fertility-control methods, supports the use of the less invasive and more cost-effective levonorgestrel implants as the preferred fertility-control method. Conclusions In addition to contraceptive effects, broad-scale fertility control may have resulted in a compensatory higher breeding success in the untreated population, possibly in response to decreasing densities, increased resource availability or behavioural responses to population management. Implications Although compensatory breeding mechanisms can reduce the effectiveness of fertility control at the population level, ongoing fertility-control management can still be successful at reducing overabundant koala populations to sustainable levels with significant long-term commitment, provided that annual control targets are continuously met.
Publisher: Cold Spring Harbor Laboratory
Date: 04-03-2022
DOI: 10.1101/2022.03.03.482781
Abstract: The international wildlife trade presents severe conservation and environmental security risks. However, no international regulatory framework exists to monitor the trade of species not listed in the appendices of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). We explored the composition and dynamics of internationally regulated versus non-regulated trade, focussing on importations of wild-caught terrestrial vertebrates entering the United States of America (US) from 2009-2018. The prominence of the US in global wildlife imports and its detailed data collection conventions allows a unique opportunity to formally assess this substantial but often overlooked and understudied component of the legal wildlife trade. We found 3.6 times the number of unlisted species in US imports compared with CITES-listed species (1,366 versus 378). CITES-listed species were more likely to face reported conservation threats relative to the unlisted species (71.7% vs 27.5%). Yet, we found 376 unlisted species facing conversation threats, 297 species with unknown population trends and 139 species without an evaluation by the IUCN Red List of Threatened Species. Unlisted species appeared novelly in imports at 5.5 times higher rates relative to CITES-listed species, where unlisted reptiles saw the largest rate of entry, averaging 53 unique species appearing in imports for the first time per year. Overall trade volumes were substantially larger for unlisted imports with approximately 11 times the number of animals relative to CITES-listed imports, however, import volumes were similar when compared at a species-by-species level. We found that the countries that were top exporters for CITES-listed shipments were mostly different from exporters of unlisted species. In highlighting the vulnerabilities of the wild-caught unlisted vertebrate trade entering the US and in the face of increasing global demand, we recommend governments adapt policies to monitor the trade of all wildlife.
Publisher: Wiley
Date: 07-10-2022
DOI: 10.1111/COBI.13978
Abstract: The international wildlife trade presents severe conservation and environmental security risks, yet no international regulatory framework exists to monitor the trade of species not listed in the appendices of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). We explored the composition and dynamics of internationally regulated versus nonregulated trade, with a focus on importations of wild‐caught terrestrial vertebrates entering the United States from 2009 to 2018. We used 10 years of species‐level trade records of the numbers of live, wild‐caught animals imported to the United States and data on International Union for the Conservation of Nature (IUCN) estimates of extinction risk to determine whether there were differences in the ersity, abundance, and risk to extinction among imports of CITES‐listed versus unlisted species. We found 3.6 times the number of unlisted species in U.S. imports compared with CITES‐listed species (1366 vs. 378 species). The CITES‐listed species were more likely to face reported conservation threats relative to unlisted species (71.7% vs. 27.5%). However, 376 unlisted species faced conversation threats, 297 species had unknown population trends, and 139 species were without an evaluation by the IUCN. Unlisted species appearing for the first time in records were imported 5.5 times more often relative to CITES‐listed species. Unlisted reptiles had the largest rate of entry, averaging 53 unique species appearing in imports for the first time per year. Overall trade quantities were approximately 11 times larger for imports of unlisted species relative to imports of CITES‐listed species. Countries that were top exporters of CITES‐listed species were mostly different from exporters of unlisted species. Because of the vulnerabilities of unlisted, traded species entering the United States and increasing global demand, we strongly recommend governments adapt their policies to monitor and report on the trade of all wildlife.
Location: Australia
No related grants have been discovered for Freyja Watters.