Bustamante Heidi M, Livo Lauren J, Carey Cynthia
Department of Integrative Physiology, University of Colorado, Boulder, Colorado, USA.
Integr Zool. 2010 Jun;5(2):143-153. doi: 10.1111/j.1749-4877.2010.00197.x.
Considerable controversy exists concerning whether or not climate changes (particularly global warming) are causing outbreaks of a lethal amphibian pathogen, the chytrid fungus Batrachochytrium dendrobatidis (Longcore, Pessier & D.K. Nichols 1999). In the present study, groups of Panamanian golden frogs (Atelopus zeteki Dunn, 1993), a critically endangered amphibian thought to be nearly extinct in Panama, were exposed to varying dosages of zoospores of Batrachochytrium dendrobatidis, temperatures and hydric environments in order to learn whether this species is susceptible to this pathogen and, if so, how environmental factors affect survival. This pathogen proved to be highly lethal for A. zeteki. Frogs exposed to a dosage of 100 Bd zoospores survived significantly (P<0.0001) longer than those that had been exposed to 10(4) or 10(6) zoospores. Exposed frogs housed at 23 °C survived significantly (P<0.0001) longer than those that were housed at 17 °C. Exposed frogs held in dry conditions survived significantly longer than those in wet conditions (P<0.0001). As a laboratory study, these results do not directly test hypotheses about the relation between climate change and the decline of these frogs in the field, but they inform the discussion about how environmental conditions can have an impact on the interaction between a susceptible amphibian and this pathogen. These data do not support the contention that rising global temperatures are necessary to cause the death of amphibians infected with this pathogen because the pathogen was equally lethal at 17 as at 23 °C, and frogs at the warmer temperature lived significantly longer than those at the cooler one.
气候变化（尤其是全球变暖）是否正在引发一种致命的两栖动物病原体——蛙壶菌（Batrachochytrium dendrobatidis，Longcore、Pessier和D.K. Nichols，1999年）的爆发，这一问题存在着相当大的争议。在本研究中，将巴拿马金蛙（Atelopus zeteki Dunn，1993年）分为若干组，巴拿马金蛙是一种极度濒危的两栖动物，在巴拿马被认为几乎灭绝，让它们接触不同剂量的蛙壶菌游动孢子、温度和湿度环境，以了解该物种是否易感染这种病原体，如果是，环境因素如何影响其存活。结果证明这种病原体对巴拿马金蛙具有高度致死性。接触100个蛙壶菌游动孢子剂量的青蛙存活时间显著（P<0.0001）长于接触10⁴或10⁶个游动孢子的青蛙。饲养在23℃的接触病原体青蛙存活时间显著（P<0.0001）长于饲养在17℃的青蛙。处于干燥条件下的接触病原体青蛙存活时间显著长于处于潮湿条件下的青蛙（P<0.0001）。作为一项实验室研究，这些结果并未直接检验关于气候变化与这些青蛙在野外数量减少之间关系的假设，但它们为关于环境条件如何影响易感两栖动物与这种病原体之间相互作用的讨论提供了信息。这些数据不支持这样的观点，即全球气温上升是导致感染这种病原体的两栖动物死亡的必要条件，因为该病原体在17℃和23℃时致死性相同，且处于较高温度下的青蛙存活时间显著长于处于较低温度下的青蛙。
