E-Letter responses to:

p-forum: Joseph R. Mendelson, III, Karen R. Lips, Ronald W. Gagliardo, George B. Rabb, James P. Collins, James E. Diffendorfer, Peter Daszak, Roberto Ibáñez D., Kevin C. Zippel, Dwight P. Lawson, Kevin M. Wright, Simon N. Stuart, Claude Gascon, Hélio R. da Silva, Patricia A. Burrowes, Rafael L. Joglar, Enrique La Marca, Stefan Lötters, Louis H. du Preez, Ché Weldon, Alex Hyatt, José Vicente Rodriguez-Mahecha, Susan Hunt, Helen Robertson, Brad Lock, Christopher J. Raxworthy, Darrel R. Frost, Robert C. Lacy, Ross A. Alford, Jonathan A. Campbell, Gabriela Parra-Olea, Federico Bolaños, José Joaquin Calvo Domingo, Tim Halliday, James B. Murphy, Marvalee H. Wake, Luis A. Coloma, Sergius L. Kuzmin, Mark Stanley Price, Kim M. Howell, Michael Lau, Rohan Pethiyagoda, Michelle Boone, Michael J. Lannoo, Andrew R. Blaustein, Andy Dobson, Richard A. Griffiths, Martha L. Crump, David B. Wake, and Edmund D. Brodie Jr. BIODIVERSITY: Confronting Amphibian Declines and Extinctions Science 2006; 313: 48 [Summary] [Full text] [PDF]

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Published E-Letter responses:

Action on Amphibian Extinctions: Going Beyond the Reductive

J. Alan Pounds, Ana Carolina Carnaval, Robert Puschendorf, Célio F. B. Haddad, Karen L. Masters   (28 August 2007)

Is There a Role for Evolutionary Management in Addressing the Threat of Chytridiomycosis?

Robert C. Lacy, George B. Rabb   (12 April 2007)

Is There a Role for Evolutionary Management in Addressing the Threat of Chytridiomycosis?

Martin A. Schlaepfer   (23 March 2007)

Action on Amphibian Extinctions: Going Beyond the Reductive 28 August 2007
J. Alan Pounds, goldtoad@racsa.co.cr Monteverde Cloud Forest Preserve, Tropical Science Center, Santa Elena, Puntarenas 5655-73, Costa Ri, Ana Carolina Carnaval, Robert Puschendorf, Célio F. B. Haddad, Karen L. Masters Respond to this E-Letter: Re: Action on Amphibian Extinctions: Going Beyond the Reductive	Amphibians are disappearing from seemingly undisturbed areas around the world. How should humanity respond? In a previous Letter (8 December 2006, p. 1541), we criticized the Policy Forum of J. R. Mendelson III et al. (7 July 2006, p. 48) for implying that the main challenge lies in combating a poorly known chytrid fungus, Batrachochytrium dendrobatidis, and not mentioning the need to address large-scale environmental deterioration such as pollution and climate change. Contrary to statements in their reply, we did not recommend that conservationists neglect “the proximate causes” of the declines and fight only “the ultimate causes.” This complex problem (1-3) requires action on all fronts. One approach is to manage areas that may be natural refuges from extinction. This contrasts with M. A. Schlaepfer’s idea (E-Letters, 23 March 2007) of creating artificial conditions in the wild to restrain the chytrid. As R. C. Lacy and G. B. Rabb pointed out (E-Letters, 12 April 2007), this pathogen tolerates diverse environments. Amphibians might elude it under certain conditions (4) but cannot easily avoid it altogether. In many places, however, frogs and fungus coexist (5-10). Such patterns may reflect not only history and genetics, but also environment. Although no conservation strategy can benefit all amphibians, identifying the essence of potential refuges may help in targeting areas for protection or restoration. For populations in these areas, evolutionary viability depends on ecosystem integrity and habitat connectivity. Wholesale environmental deterioration undermines this integrity and abets other enemies besides the chytrid (1-3). If the spiraling decay continues, today’s refuges may be tomorrow’s tombs. Mendelson et al. responded to our Letter (8 December 2006, p. 1541) by defending the Amphibian Conservation Action Plan, which we did not criticize but quoted affirmatively on this issue. We questioned their Policy Forum for relegating such an urgent matter to the Supporting Online Material. Captive programs offer another sort of refuge and additional opportunities for action. We agree with Schlaepfer that they facilitate work on resistance to disease, although we share Lacy and Rabb’s concerns about using trial-by-fire selection to modify gene pools. In our Letter, we argued that captive breeding is a limited option for conservation but can be worthwhile. Indeed, it opens a door to education and promotes various lines of research that are fundamental to countering disease. This research should be interdisciplinary and contemplate multiple levels of organization, from molecules to ecosystems. One priority is to study amphibians, the chytrid, and other interacting organisms in the lab and field to explore how the interplay of environment and species’ traits (morphological, physiological, and behavioral) influences disease dynamics. Predicting the outcome of the critical species interactions requires an understanding of how potential factors such as stress (1-3) or microbial species composition (6) are related to environmental variation and change. How might the proposed action influence public opinion and therefore policy? This depends on how it is presented and the accompanying outreach. Replying to our Letter, Mendelson et al. dismissed our call for outreach as “vague” and misquoted us as saying captive programs engender false hope and complacency. What may do this, we argued, is the suggestion that “intensive care,” a metaphor for science and technology aimed at conserving particular taxa (11), can by itself halt the extinctions. Unless humanity acts now to stop large-scale environmental deterioration, efforts to save amphibians are likely to be overwhelmed in the coming decades. J. Alan Pounds Monteverde Cloud Forest Preserve, Tropical Science Center, Santa Elena, Puntarenas 5655-73, Costa Rica. Ana Carolina Carnaval Museum of Vertebrate Zoology, University of California, Berkeley, Berkeley, CA 94720–3160, USA. Robert Puschendorf School of Marine and Tropical Biology, James Cook University, Townsville, Queensland 4811, Australia. Célio F. B. Haddad Departamento de Zoologia, I.B., UNESP, Av. 24 A, 1515, Bela Vista, 13506-900 Rio Claro, S.P., Brazil. Karen L. Masters Council for International Educational Exchange, Monteverde, Puntarenas 5655-26, Costa Rica. References 1. R. A. Alford, K. S. Bradfield, S. J. Richards, Nature 447, doi:10.1038/ nature05940 (2007). 2. I. Di Rosa, F. Simoncelli, A. Fagotti, R. Pascolini, Nature 447, doi:10.1038/nature05941 (2007). 3. J. A. Pounds et al., Nature 447 doi:10.1038/nature05942 (2007). 4. J. A. Pounds, R. Puschendorf, Nature 427, 107 (2004). 5. J. R. Loncore, J. E. Longcore, A. P. Pessier, W. A. Halteman, J. Wildl. Manage. 71, 435 (2007). 6. D. C. Woodhams et al., Biol. Conserv. 138, 390 (2007). 7. R. Puschendorf, F. Bolaños, G. Chaves, Biol. Conserv. 132, 136 (2006). 8. A. C. Oliveira de Queiroz Carnaval, R. Puschendorf, O. L. Peixoto, V. Kruth Verdade, M. Trefaut Rodriques, Ecohealth 3, 41 (2006). 9. M. Ouellet, I. Mikaelian, B. D. Pauli, J. Rodrigue, D. M. Green, Conserv. Biol. 19, 1431 (2005). 10. R. Retallick, H. McCallum, R. Speare, PLoS Biology 2, 1 (2004). 11. E. O. Wilson, Conserv. Biol. 14, 1 (2000).
Is There a Role for Evolutionary Management in Addressing the Threat of Chytridiomycosis? 12 April 2007
Robert C. Lacy, Population geneticist Chicago Zoological Society, George B. Rabb Respond to this E-Letter: Re: Is There a Role for Evolutionary Management in Addressing the Threat of Chytridiomycosis?	In his E-Letter, M. A. Schlaepfer identified a potentially important role for captive populations of amphibians that are being protected from the fungus Batrachochytrium dendrobatidis (Bd). Indeed, the Amphibian Conservation Action Plan calls for research on the fungus, its mechanism of spread, how it causes death, and the development of resistance and urges that funds be allocated for such work. Although the potential for captive survival assurance colonies to be valuable for research has been recognized, we should not overestimate our ability to develop useful genetically resistant stocks or determine environmental conditions that effectively impede the fungus. Seemingly simple solutions such as changing the temperature of breeding sites ignore the fact that amphibians, and especially their breeding biology, are often precisely tuned to such environmental conditions. Bd appears to have a wider environmental tolerance than does almost any amphibian. It might be possible to develop resistant amphibian populations through selection. However, chytrid is not the only threat facing amphibians. Strong selection for one trait usually causes both rapid depletion of genetic variation throughout the rest of the genome (because very few survivors would constitute the founding stock for population reestablishment) and often physiological and evolutionary trade-offs that compromise ability to withstand other stresses. A concatenation of diverse threats to amphibians–including increased UV, climate change, and a huge array of ecotoxins–may have increased their susceptibility to Bd because of physiological stress or genetic adaptation to initial threats having left the organism more vulnerable to different stresses. Maintaining high diversity within rescued populations may be more important to eventual success than selection for a specific adaptation. Breeding programs should use strategies that retain as much variation as possible even while selection might be imposed on some experimental stocks. It is more likely that resistance will evolve in nature, and captive colonies might then be needed to help restore variation to relict wild populations. Any releases of genetically modified individuals will need to be preceded by carefully controlled experiments to ensure that there will be benefit while minimizing the possibility of damage. Finding solutions to this crisis will not be easy, cheap, or quick, but we must pursue every opportunity if we are not to risk losing much of an entire vertebrate class, with unimaginable ecological consequences. Amphibians interact with their environments with an intimacy not seen in birds and mammals and as such are sensitive indicators of environmental threats to us all. Robert C. Lacy and George B. Rabb Chicago Zoological Society
Is There a Role for Evolutionary Management in Addressing the Threat of Chytridiomycosis? 23 March 2007
Martin A. Schlaepfer Department of Integrative Biology, University of Texas Respond to this E-Letter: Re: Is There a Role for Evolutionary Management in Addressing the Threat of Chytridiomycosis?	Amphibians currently face an extinction crisis, and in a recent Policy Forum, Mendelson et al. (7 July 2006, p. 48) outline the urgent need to address the threat of chytridiomycosis, a potentially lethal disease caused by the fungus Batrachochytrium dendrobatidis (Bd). Chytridiomycosis is the likely cause of many amphibian population declines, and Mendelson et al.. suggest using captive breeding programs to protect species that are believed to be most susceptible to the disease. Pounds et al. (8 Dec. 2006, p. 1541), however, have countered that captive breeding is costly and cannot ensure that susceptible species will ever be reintroduced into the wild. Increasing evidence of amphibian populations coexisting with Bd suggests a novel role for captive breeding facilities. Wild-caught individuals of at-risk species could be quarantined and experimentally exposed to Bd to select for resistance. Even if only a small number of individuals survive, their number could be augmented in captivity to provide a large resistant population (assuming resistance is partially heritable) for subsequent reintroductions. If all captive individuals died from exposure to Bd, researchers could (i) repeat the experiment in the hopes of capturing resistant individuals, (ii) better justify the high costs of long-term captive breeding, or (iii) explore the possibility of creating refugia in the wild (e.g., bodies of water >30°C). The use of captive breeding as a source of evolutionary-enlightened management promises not only to reconcile what appears to be an emerging dispute between scientists with a common goal, but also to create long-term and financially efficient solutions to an important conservation problem.