Opportunities and costs for preventing vertebrate extinctions

The Role of Zoos and Aquariums in a Changing World

Zoos and aquariums have evolved significantly. From their origins as enclosures for the mere entertainment of the public, these institutions have undertaken new functions responding to the biodiversity crisis and social demands. Modern zoos and aquariums have the opportunity to educate people, contribute to species conservation, and produce animal-related research. However, there is increasing criticism toward the outcomes of their actions and the holding of species in their facilities. This review offers an integrated analysis of the state of knowledge about the role that zoos and aquariums play today. It describes their performance regarding their conservation, education, and research functions, highlighting general patterns and offering future perspectives. It identifies some challenges common to all these institutions, concluding that the way they keep up with the ever-growing social and environmental expectations will be decisive hereafter.

Integrating biobanking could produce significant cost benefits and minimise inbreeding for Australian amphibian captive breeding programs

Captive breeding is an important tool for amphibian conservation despite high economic costs and deleterious genetic effects of sustained captivity and unavoidably small colony sizes. Integration of biobanking and assisted reproductive technologies (ARTs) could provide solutions to these challenges, but is rarely used due to lack of recognition of the potential benefits and clear policy direction. Here we present compelling genetic and economic arguments to integrate biobanking and ARTs into captive breeding programs using modelled captive populations of two Australian threatened frogs, namely the orange-bellied frog Geocrinia vitellina and the white bellied frog Geocrinia alba . Back-crossing with frozen founder spermatozoa using ARTs every generation minimises rates of inbreeding and provides considerable reductions in colony size and program costs compared with conventional captive management. Biobanking could allow captive institutions to meet or exceed longstanding genetic retention targets (90% of source population heterozygosity over 100 years). We provide a broad policy direction that could make biobanking technology a practical reality across Australia's ex situ management of amphibians in current and future holdings. Incorporating biobanking technology widely across this network could deliver outcomes by maintaining high levels of source population genetic diversity and freeing economic resources to develop ex situ programs for a greater number of threatened amphibian species.

Observations on spindly leg syndrome in a captive population of Andinobates geminisae

Amphibian health problems of unknown cause limit the success of the growing number of captive breeding programs. Spindly leg syndrome (SLS) is one such disease, where affected individuals with underdeveloped limbs often require euthanization. We experimentally evaluated husbandry-related factors of SLS in a captive population of the critically endangered frog, Andinobates geminisae. SLS has been linked to tadpole nutrition, vitamin B deficiency, water filtration methods, and water quality, but few of these have been experimentally tested. We tested the effects of water filtration method and vitamin supplementation (2017) and the effects of tadpole husbandry protocol intensity (2018) on time to metamorphosis and the occurrence of SLS. We found that vitamin supplementation and reconstituted reverse osmosis filtration of tadpole rearing water significantly reduced SLS prevalence and that reduced tadpole husbandry delayed time to metamorphosis. A fortuitous accident in 2018 resulted in a decrease in the phosphate content of rearing water, which afforded us an additional opportunity to assess the influence of phosphate on calcium sequestration. We found that tadpoles that had more time to sequester calcium for ossification during development had decreased the prevalence of SLS. Taken together, our results suggest that the qualities of the water used to rear tadpoles plays an important role in the development of SLS. Specifically, filtration method, vitamin supplementation, and calcium availability of tadpole rearing water may play important roles. Focused experiments are still needed, but our findings provide important information for amphibian captive rearing programs affected by high SLS prevalence.

Reproductive biotechnology and critically endangered species: Merging in vitro gametogenesis with inner cell mass transfer

A fifth of mammalian species face the risk of extinction. A variety of stresses, and lack of sufficient resources and political endorsement, mean thousands of further extinctions in the coming years. Once a species has declined to a mere few individuals, in situ efforts seem insufficient to prevent its extinction. Here we propose a roadmap to overcome some of the current roadblocks and facilitate rejuvenation of such critically endangered species. We suggest combining two advanced assisted reproductive technologies to accomplish this task. The first is the generation of gametes from induced pluripotent stem cells, already demonstrated in mice. The second is to 'trick' the immunological system of abundant species' surrogate mothers into believing it carries conceptus of its own species. This can be achieved by transferring the inner cell mass (ICM) of the endangered species into a trophoblastic vesicle derived from the foster mother's species. Such synthesis of reproductive biotechnologies, in association with in situ habitat conservation and societal changes, holds the potential to restore diversity and accelerate the production of animals in the most endangered species on Earth.

Viable Cell Culture Banking for Biodiversity Characterization and Conservation

Because living cells can be saved for indefinite periods, unprecedented opportunities for characterizing, cataloging, and conserving biological diversity have emerged as advanced cellular and genetic technologies portend new options for preventing species extinction. Crucial to realizing the potential impacts of stem cells and assisted reproductive technologies on biodiversity conservation is the cryobanking of viable cell cultures from diverse species, especially those identified as vulnerable to extinction in the near future. The advent of in vitro cell culture and cryobanking is reviewed here in the context of biodiversity collections of viable cell cultures that represent the progress and limitations of current efforts. The prospects for incorporating collections of frozen viable cell cultures into efforts to characterize the genetic changes that have produced the diversity of species on Earth and contribute to new initiatives in conservation argue strongly for a global network of facilities for establishing and cryobanking collections of viable cells.

Meeting the Aichi targets: Pushing for zero extinction conservation

Effective protection of the ~19 000 IUCN-listed threatened species has never been more pressing. Ensuring the survival of the most vulnerable and irreplaceable taxa and places, such as those identified by the Alliance for Zero Extinction (AZE) species and their associated sites (AZEs&s), is an excellent opportunity to achieve the Aichi 2020 Targets T11 (protected areas) and T12 (preventing species extinctions). AZE taxa have small, single-site populations that are especially vulnerable to human-induced extinctions, particularly for the many amphibians. We show that AZEs&s can be protected feasibly and cost-effectively, but action is urgent. We argue that the Alliance, whose initial main aim was to identify AZEs&s, must be followed up by a second-generation initiative that directs and co-ordinates AZE conservation activities on the ground. The prominent role of zoos, conservation NGOs, and governmental institutions provides a combination of all-encompassing knowhow that can, if properly steered, maximize the long-term survival of AZEs&s.

Loss and conservation of evolutionary history in the Mediterranean Basin

BACKGROUND

Phylogenetic diversity and evolutionary distinctiveness are highly valuable components of biodiversity, but they are rarely considered in conservation practices. Focusing on a biodiversity hotspot, the Mediterranean Basin, we aimed to identify those areas where evolutionary history is highly threatened and range-restricted in the region. Using null models, we first compared the spatial distributions of three indices: two measured threatened evolutionary history-Expected PDloss and Heightened Evolutionary distinctiveness and Global Endangerment-and one measured endemic evolutionary history-Biogeographically Evolutionary Distinctiveness. We focused on three vertebrate groups with high proportions of endemic, threatened species: amphibians, squamates and terrestrial mammals. Second, we estimated the spatial overlap of hotspots of threatened and endemic evolutionary history within the network of protected areas under several conservation scenarios.

RESULTS

Areas that concentrate evolutionary history of conservation interest greatly differed among taxa and indices, although a large proportion of hotspots were identified in the Maghreb, in the East of the Mediterranean Basin as well as in islands. We found that, in a minimum conservation scenario, there was a significant proportion of hotspots for amphibians and squamates that were protected but not for terrestrial mammals. However, in a strong conservation scenario, only few hotspots overlapped with protected areas and they were significantly less protected than in a model where hotspots were chosen randomly.

CONCLUSIONS

Some sites concentrate highly threatened and range-restricted evolutionary history of the Mediterranean basin and their conservation could be much improved. These sites are relevant for conservation studies aimed at designing new conservation actions to preserve evolutionary history and the option values it represents.