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Course:CONS200/2025WT2/The use of Reproductive Technologies for Amphibian Conservation

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Introduction

Panamanian Golden Toad (Atelopus Zeteki)

Amphibians are four-limbed vertebrates whose life cycle begins in water as larvae and as they age, transition to land. Currently, there are nearly 8,000 documented species, with 88% classified as frogs, 9% as salamanders, and about 3% as caecilians[1]. Unfortunately, recent studies report that up to 55% of these species face the risk of extinction and decline, a rate that is dramatically higher than most other vertebrate groups[2]. This statistic calls for urgent conservation efforts because amphibians play important roles in maintaining ecosystem health. One method scientists are exploring to combat this decline is advanced reproductive technologies that offer new hope for amphibian species that are critically endangered or rapidly declining, especially in cases where traditional conservation strategies fall short[3].

History: The Decline of Amphibian Species

Over the past 40 years, amphibian populations globally have seen a decline that is only worsening today [2]. An understanding of the reasons behind this loss of biodiversity that has unfolded over time can provide valuable context for examining its broader impacts.

Anthropogenic Drivers of Decline

Anthropogenic activities are key contributors to amphibian biodiversity loss, with the phenomenon of the sixth mass extinction taking place. As human-driven harm, such as deforestation, urban development, climate change, and the introduction of non-native species, has led to major damage in amphibian habitats [4]. This has led to fragmentation and smaller breeding grounds in areas where amphibians used to thrive [5]. Resulting in many species experiencing sharp population declines, with some entirely disappearing from their once-native regions.

Human-driven damage to amphibian habitats can be observed in regions such as Central America, where climate change has disrupted critical breeding and feeding areas. In Costa Rica, for example, human impacts on the climate have changed rainfall patterns. This caused amphibian species such as “The Golden Toad” to go extinct as it could not survive the drastic habitat changes [6]. Its disappearance marked one of the first cases of amphibian climate-related extinction, showing the fragile environments they depend on and the consequences of any slight changes.

Invasive Species and Biodiversity Loss

Amphibian species are threatened by invasive species, which are non-native organisms introduced to new environments where they cause harm to the local ecosystem. Invasive species introduced pathogens, altered food webs, and competed for the same resources as amphibians [7]. This leads to species decline because amphibians have specialized habitat needs and are highly sensitive to environmental changes, which means alterations can quickly destabilize a population.

The damage of invasive species on amphibian populations can be particularly quantified in El Copé, Panama, where the chytrid fungi, also known as Batrachochytrium Dendrobatidis, have led to over 30 species lost, representing 40% of the total amphibian population in the area [8]. The fungi infected the amphibian's skin, causing essential functions to be harmed. This rapid decline shows the severity of damage which invasive pathogens can cause to amphibian ecosystems, contributing to widespread biodiversity loss.

Importance of Amphibians

Amphibians play important roles in maintaining ecosystem health through contributions to biodiversity, regulation of insect populations, and their function as bioindicators of environmental conditions[9]. Their disappearance can signal serious ecological issues, causing their conservation to be critical for environmental health and biodiversity. This calls for serious prevention methods as continued amphibian decline could trigger effects such as uncontrolled insect populations and disruption in food chains, which can impact both wildlife survival and human food security.

Technology in Amphibian Conservation

Technology and Conservation Efforts

Amphibian Biobanking Efforts

Scientists and conservationists are increasingly turning to advanced technologies to combat the challenges of declining amphibian species. These tools enhance our understanding of amphibians and support breeding, disease management, habitat restoration, and genetic preservation. The importance of technological advancement is vital in addressing the current status of amphibian populations during the sixth mass extinction. Through scientific research and experimentation, breakthroughs have been made in various reproductive technological methods, providing a promising outlook on the future of the global population of amphibian species.

Technological Advancements in Conservation

Artificial Fertilization and Reproductive Technologies: To counteract the rapid decline of amphibian species, scientists have adopted reproductive technologies such as hormone-induced spawning, artificial fertilization, and in vitro fertilization (IVF). These techniques have allowed successful reproduction in species that struggle to breed in captivity. For example, conservationists used hormone therapies in Sub-Saharan areas to experiment on the Hoplobatrachus occipitalis (Tiger frog), which were successful trials in spawning and fertilization [10]. Quantified analysis suggests that utilizing this new technology can significantly aid in uplifting endangered species populations and maintaining biodiversity, however, it is still limited and currently being tested by scientists worldwide.

Gene Banking and Biobanking in Amphibian Conservation: Cryopreservation of amphibian sperm, eggs, and somatic cells has become a cornerstone of genetic preservation efforts. Through scientific efforts, this strategy essentially preserves genetic diversity, creating a safety net for dying species, further allowing for the maintenance of amphibian populations. Biobanks provide genetic "insurance" by preserving biodiversity that might otherwise be lost through continued extinction. In Australia, biobanking of Philoria Frosti (Baw Baw frog) genetic material, along with other reproductive measures, has enabled successful captive breeding and future reintroduction plans of the critically endangered species[11]. This phenomenon allows scientists to preserve the long-term validity of threatened species, like the Baw Baw frog, maintaining their existence.

DNA Barcoding and Species Identification: DNA barcoding helps distinguish between morphologically similar species and track genetic diversity, enabling more targeted conservation. Scientists used DNA barcoding in the Brazilian Amazon to identify previously unrecognized species within the Pristimantis Genus [12]. This allowed researchers to apply species-specific conservation strategies and avoid the mismanagement of species. This advancement in technology can also aid in the process of identifying invasive species, which are a crucial threat to the decline of amphibian species worldwide. These methods aid scientists, as observed within Ecuador, to monitor ecosystems and biodiversity along with a recognition of genetic differentiation within areas aiding captive breeding programs.    

Remote Sensing and eDNA Identification: DNA (eDNA) detection allows scientists to identify amphibian species in water samples without direct observation. Meanwhile, drones and remote sensors are used for real-time habitat monitoring, helping detect threats like deforestation and pollution. Within Mexico, scientists utilized eDNA in order to identify and monitor native Axolotl species in their wild habitats for further experimentation [13]. This species is a key example of methods like eDNA aid in tracking wildlife populations, providing significant data on biodiversity and the ecosystem the species is currently within. Identification provided by the technology further quantifies data through monitoring the decline of species and helps boost reproductive matters needed to restore populations within specific areas.

Successes with Conservation Technology:

Mexican Axolotl

Although technological advancements are still currently being tested worldwide on amphibian species, scientists have been able to utilize factors such as gene banking and IVF, along with support from eDNA, to promote reproduction. A primary example of this new technology can be exemplified by Ambystoma Mexicanum (axolotl), which is native to Mexico, benefiting from artificial habitats and reproductive technologies [13]. Induced population expansion through captive breeding utilizing reproductive technology has shown a significant increase, allowing for promising scientific factors counteracting extinction. These efforts have slowed population declines and contributed to scientific understanding of the species’ unique biology.

In Panama, the Amphibian Rescue and Conservation Project used assisted reproductive technologies consisting of IVF and biobanking to breed and maintain the biodiversity of the Panamanian golden frog, resulting in sustained captive populations [14]. This success has provided scientists with optimism through utilizing the advancing reproductive technology, making substantial breakthroughs to counteract threats like Chytrid fungus, which currently threatens this species' habitat.

In various Puerto Rican zoos, cryopreserved sperm were successfully used in IVF procedures with endangered Puerto Rican crested toads, leading to healthy offspring with enhanced genetic diversity [15]. This example serves for crucial scientific implementation of advanced technology, specifically cryopreservation as a measure of reproductive technology that is further utilized in artificial insemination. Scientists can utilize the cryopreservation of sperm and egg cells through experimentation in genetic cloning mechanisms to induce reproduction and increase populations. These reproductive technologies are still being experimented with, however, they serve as a potential critical solution to solve the global decline of amphibian species.

Challenges of Technology in Amphibian Conservation

Technical Difficulties: Reproductive techniques often require very specific protocols relative to each different species. Essentially, in the case of reproductive technologies, what works for one species may not work for another. This can be analyzed through examples of amphibian species undergoing hormone-induced procedures, such as IVF. These reproductive tools may work effectively for one amphibian species but may not produce the same results for others. For example, the hormone therapies used within the studies for the Tiger frog were effective, resulting in fertilization and spawning, but these same procedures were not effective on Australian southern bell frogs in early testing [10].

Australian Northern Corroboree Frog

Scaling and Optimization: Technologies like cryopreservation, sperm/egg collection, and artificial insemination are still challenging to scale efficiently. Although research is still currently being conducted on the efficiency of these reproductive measures, the overall large-scale capabilities have yet to be implemented worldwide. For example, through experimentation in Australia utilizing the Northern Corroboree frog in two years of induced fertilization, they were able to breed about 800 eggs [16]. These operations of reproductive technology usage are still mostly in developmental phases, as exhibited in the experimentation process; therefore, large-scale implementation has not yet been implemented.

Cost and Accessibility: These technologies are expensive and often unavailable in regions with the most extraordinary amphibian diversity, such as parts of South America and Southeast Asia. Stated through research and experiments utilizing reproductive measures, there are ways to minimize the expensive costs of reproductive technology that is ready to be utilized. However, experts further suggest that many regions are not yet willing to implement reproductive strategies as they are still undergoing testing phases and are not considered cost-efficient [17]. The limited accessibility due to mistrust and funding allocation hinders the effective ability of reproductive technologies.

Data Gaps: Lack of biological data on rare and understudied species hinders the development of targeted conservation techniques. As relatively innovative technologies are being implemented regarding technology for reproduction, there is a variety of experimentation which is still necessary in addressing amphibian population decline. In addition, with experimentation still taking place, the role of reproductive technology still lacks clarity in its effectiveness in restoring various species [18]. Along with these ideas and having certain procedures be inefficient across genetically varied species, data gaps emerge when questioning the abundance of variation..

Ethical Concerns: Some critics raise concerns about manipulating natural reproductive processes, especially in the absence of broader habitat protection efforts. The processes of reproductive technology also utilize captive breeding measures and further induce experimentation on amphibian species, which creates ethical concerns. The validity of ethical experimentation being done is said to be carried out under strict guidelines [17]. However, public concerns are still always going to be prominent, questioning ethical procedures with topics regarding reproductive technologies being tested on endangered amphibian species.

External Factors Supporting The Utilization of Reproductive Technologies

Roles of Zoos and Aquariums in Amphibian Conservation

Zoos and aquariums play a vital role in amphibian conservation by providing safe environments for endangered species, facilitating captive breeding programs, and advancing scientific research. These institutions implement cutting-edge reproductive technologies like cryopreservation. For example, scientists are able to use artificial insemination to improve genetic diversity in species that are difficult to breed [18]. By maintaining stable captive populations, zoos and aquariums also act as genetic reservoirs for future reintroduction efforts in the wild, promoting conservation efforts. These areas serve as scientific research facilities to implement and innovate, advancing reproductive technology to boost amphibian species.

Implementation of Captive Breeding Programs:

Captive breeding programs have emerged as critical tools for amphibian conservation, especially when paired with genetic management and reproductive technologies. In research conducted by experts, hormone-assisted reproduction in the mountain yellow-legged frog (Rana muscosa) yielded a 70% fertilization rate, a significant milestone for a species once considered nearly extinct [19]. The captive breeding programs help scientists continue experiencing biobanking, especially in cases such as biobanking and cryopreservation, demanding species cooperation. Furthermore, the programs support the reproductive technology being innovated by scientists, allowing for the preservation of species being born and preparing them for reintroduction into the wild.  

Future Outlook on Amphibian Conservation

Beyond technological interventions, taking a holistic approach to addressing the root cause of amphibian decline is also vital. Society must mitigate anthropogenic issues, such as climate change, which will allow amphibian habitats to thrive. Disease control and research must then be implemented to prevent the spread of deadly pathogens, which continue to threaten the livelihoods of countless amphibian species [8]. This would allow for the recovery of vulnerable populations and the stabilization of countless threatened ecosystems.

Southern Brown Tree Frog

Moving forward, individuals need to begin raising public awareness about amphibian conservation as it is critical to the success of conservation efforts. Educational programs in schools, media campaigns, and community workshops that effectively spread the message of amphibian species awareness are crucial. Supported by transparent educational materials and targeted outreach activities, these programs enable individuals to make a tangible impact on amphibian conservation, ultimately contributing to broader global conservation [17]. Thus, further involving local communities in these efforts strengthens the connection between people and the species they are working to protect, enhancing the effectiveness of conservation strategies. Community-based conservation efforts are particularly effective because they help individuals understand the significance of preserving local species and ecosystems. When informed and involved, communities are more likely to take ownership of conservation issues and actively participate in preservation efforts.

Conclusion: Optimism or Pessimism For Future Amphibian Conservation Efforts

The Outlook for Amphibian Survival

The outlook for amphibian survival is deeply intertwined with the growing challenges and the potential for practical conservation efforts. In hopes of preserving amphibian populations, we must consider that “Although plausible causes of amphibian declines have been identified, we still do not fully understand how they operate at the population level” [5]. While the decline of amphibian populations is a well-documented concern, a significant gap exists in our understanding of the precise mechanisms behind this decline. However, how these forces interact at the population level may not be completely reversible through induced reproductive technologies. This uncertainty presents difficulties for conservationists, who must develop strategies and technology that account for these unknowns, ultimately leading to pessimism for the species' future. In contrast, acknowledging the struggles that amphibians face, it is also not yet clear how catastrophic these changes will be for every species. The hope is that by continuing research, using proactive conservation methods, and advancing technology, the effects on amphibians can be mitigated, and the species can be restored.

Balancing Hopes with Challenges Ahead

As experts further suggest, the path to preservation is complex: "A major challenge for the future, therefore, lies in breaching traditional boundaries between scientific and social scientific approaches to the biodiversity crisis" [5] This statement highlights the urgent need for interdisciplinary collaboration to address the biodiversity crisis, which includes amphibian decline. Focusing on scientific research is critical to understanding the biological and environmental factors affecting the species, and the solution lies in bridging these findings with social science perspectives. Recognizing the socio-economic side of conservation, scientific research and technologies may be utilized to restore balance within declining species. Integrating scientific and social approaches is particularly crucial as we confront climate change, which is predicted to disrupt amphibian habitats further in the future. Without understanding how these changes impact human societies, such as agricultural practices or urban development, it becomes difficult to implement policies that can protect amphibians effectively. This broader approach can provide a more holistic view of the factors influencing amphibian survival and help create solutions that are not only scientifically sound but also socially and politically feasible.

Additional Information

Policy and Legislation

National and international policies are critical tools for ensuring the long-term survival of amphibians by creating frameworks for habitat protection, reducing pollutants, and managing ecosystems. Despite the growing body of knowledge regarding amphibian biology and its environmental threats, policies often fail to integrate the latest research into actionable conservation measures. Strengthening policies and incorporating innovative findings in reproductive biology, disease management, and habitat restoration is essential for enhancing the effectiveness of amphibian protection efforts [2]. A coordinated approach that combines science with policy is crucial for the sustainable management of amphibian populations worldwide, being a critical call to action.

The Role of International Agreements

International agreements, particularly the Convention on Biological Diversity (CBD), are pivotal in shaping global conservation strategies for amphibians. This international cooperation is especially crucial for species whose habitats span multiple regions, highlighting the need for transnational efforts to safeguard amphibian populations [5]. Therefore, as the CBD seeks to promote biodiversity conservation and the sustainable use of biological resources, emphasizing the importance of international cooperation in protecting vulnerable species like amphibians is needed for sustainability efforts. Ultimately, the effectiveness of these agreements hinges on the commitment of national governments to enforce policies and integrate the standards outlined in the CBD into local conservation efforts.

References

  1. ↑ Wake, D. B., & Koo, M. S. (2018). Amphibians. Current Biology, 28(21), R1174–R1179. https://doi.org/10.1016/j.cub.2018.09.028
  2. ↑ 2.0 2.1 2.2 Grant, H., Muths, E., & Adams, M. J. (2019). Amphibian conservation in the Anthropocene. Biological Conservation, 236, 543–547. https://doi.org/10.1016/j.biocon.2019.03.003
  3. ↑ Herrick, J. R. (2019). Assisted reproductive technologies for endangered species conservation: Developing sophisticated protocols with limited access to animals with unique reproductive mechanisms. Biology of Reproduction, 100(5), 1158–1170. https://doi.org/10.1093/biolre/ioz025
  4. ↑ Button, S., & Borzée, A. (2021). An integrative synthesis to global amphibian conservation priorities. Global Change Biology, 27, 4516–4529. https://doi.org/10.1111/gcb.15734
  5. ↑ 5.0 5.1 5.2 5.3 Trevor, J., Davidson, C., & Lips, K. R. (2005). The amphibian decline crisis: A watershed for conservation biology? Biological Conservation, 125(3), 271–285. https://doi.org/10.1016/j.biocon.2005.04.009
  6. ↑ Ryan, M. J., Scott, N. J., Cook, J. A., Willink, B., Chaves, G., Bolaños, F., García-Rodríguez, A., Latella, I. M., & Koerner, S. E. (2015). Too wet for frogs: Changes in a tropical leaf litter community coincide with La Niña. Ecosphere, 6(1), 4. http://dx.doi.org/10.1890/ES14-00352.1
  7. ↑ Ficetola, G. F., Thuiller, W., & Miaud, C. (2007). Prediction and validation of the potential global distribution of a problematic alien invasive species: The American bullfrog. Diversity and Distributions, 13(4), 476–485. http://www.jstor.org/stable/4539943
  8. ↑ 8.0 8.1 Zumbado-Ulate, H., Neam, K., García-Rodríguez, A., Ochoa-Ochoa, L., Chaves, G., Kolby, J. E., Granados-Martínez, S., Hertz, A., Bolaños, F., Ariano-Sánchez, D., Puschendorf, R., & Searle, C. L. (2022). Ecological correlates of extinction risk and persistence of direct-developing stream-dwelling frogs in Mesoamerica. Global Ecology and Conservation, 38, e02197. https://doi.org/10.1016/j.gecco.2022.e02197
  9. ↑ Halliday, T. R. (2008). Why are amphibians important? International Zoo Yearbook, 42(1), 1–6. https://doi.org/10.1111/j.1748-1090.2007.00037.x
  10. ↑ 10.0 10.1 Saylor, E. M., Vance, C. K., & Wilk, R. J. (2024). Efficacy of salmon GnRHa, Ovaprim®, and hCG for hormonal stimulation of spermiation in the Fowler’s toad (Anaxyrus fowleri). Conservation Physiology, 12(1), coae056. https://doi.org/10.1093/conphys/coae056
  11. ↑ Silla, A. J., & Byrne, P. G. (2023). Application of reproductive technologies to the critically endangered Baw Baw frog, Philoria frosti. Animals, 13(13), 2232. https://doi.org/10.3390/ani13132232
  12. ↑ De Oliveira, E. A. (2019). Pristimantis in the Eastern Brazilian Amazon: DNA barcoding reveals underestimated diversity in a megadiverse genus. Mitochondrial DNA Part A, 30(6), 731–738. https://doi.org/10.1080/24701394.2019.1634696
  13. ↑ 13.0 13.1 Coxe, N. (2024). Establishment of a practical sperm cryopreservation pathway for the axolotl (Ambystoma mexicanum): A community-level approach to germplasm repository development. Animals, 14(2), 206. https://doi.org/10.3390/ani14020206
  14. ↑ Zigler, A., Leung, E., Lewis, K., Reich, S., & Evans, M. (2023). Critical calls: Circadian and seasonal periodicity in vocal activity in a breeding colony of Panamanian golden frogs (Atelopus zeteki). PLOS ONE, 18(8), e0286582. https://doi.org/10.1371/journal.pone.0286582
  15. ↑ Burger, I., Tapley, B., Harding, G., Dawson, J., & Griffiths, R. A. (2021). Linking in‐situ and ex‐situ populations of threatened amphibians through genome banking. Conservation Science and Practice, 3(11), e525. https://doi.org/10.1111/csp2.525
  16. ↑ Silla, A. J., & Calatayud, N. E. (2021). Amphibian reproductive technologies: Approaches and welfare considerations. Conservation Physiology, 9(1), coab011. https://doi.org/10.1093/conphys/coab011
  17. ↑ 17.0 17.1 17.2 Clulow, J., Upton, R., Trudeau, V. L., & Clulow, S. (2019). Amphibian assisted reproductive technologies: Moving from technology to application. In W. V. Holt, J. L. Brown, & C. L. Monfort (Eds.), Reproductive sciences in animal conservation (pp. 413–463). Springer. https://doi.org/10.1007/978-3-030-23633-5_14
  18. ↑ 18.0 18.1 Phillip, B., Clulow, J., & Trudeau, V. L. (2019). The role of reproductive technologies in amphibian conservation breeding programs. Annual Review of Animal Biosciences, 7(1), 499–519. https://doi.org/10.1146/annurev-animal-020518-115056
  19. ↑ Comizzoli, P., Holt, W. V., Crosier, A. E., Wildt, D. E., & Howard, J. (2019). Breakthroughs and new horizons in reproductive biology of rare and endangered animal species. Biology of Reproduction, 101(3), 514–525. https://doi.org/10.1093/biolre/ioz031
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