Guangxi Key Laboratory for Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, Guangxi, 530000, People's Republic of China.
Department of Zoology, Faculty of Science, University of Peradeniya, Peradeniya, Kandy, 20400, Sri Lanka.
BMC Ecol Evol. 2023 Jun 27;23(1):26. doi: 10.1186/s12862-023-02132-y.
Climate affects the thermal adaptation and distribution of hosts, and drives the spread of Chytridiomycosis-a keratin-associated infectious disease of amphibians caused by the sister pathogens Batrachochytrium dendrobatidi (Bd) and B. salamandrivorans (Bsal). We focus on their climate-pathogen relationships in Eurasia, the only region where their geographical distributions overlap. Eurasia harbours invaded and native areas of both pathogens and the natural habitats where they co-exist, making it an ideal region to examine their environmental niche correlations. Our understanding of how climate change will affect their distribution is broadened by the differences in climate correlates and niche characteristics between Bd and Bsal in Asia and Europe. This knowledge has potential conservation implications, informing future spread of the disease in different regions.
We quantified the environmental niche overlap between Bd and Bsal in Eurasia using niche analyses. Results revealed partial overlap in the niche with a unique 4% of non-overlapping values for Bsal, suggesting segregation along certain climate axes. Bd tolerates higher temperature fluctuations, while Bsal requires more stable, lower temperature and wetter conditions. Projections of their Realized Climatic Niches (RCNs) to future conditions show a larger expansion of suitable ranges (SRs) for Bd compared to Bsal in both Asia and Europe, with their centroids shifting in different directions. Notably, both pathogens' highly suitable areas in Asia are expected to shrink significantly, especially under the extreme climate scenarios. In Europe, they are expected to expand significantly.
Climate change will impact or increase disease risk to amphibian hosts, particularly in Europe. Given the shared niche space of the two pathogens across available climate gradients, as has already been witnessed in Eurasia with an increased range expansion and niche overlap due to climate change, we expect that regions where Bsal is currently absent but salamanders are present, and where Bd is already prevalent, may be conducive for the spread of Bsal.
气候会影响宿主的热适应性和分布，并推动蛙壶菌病的传播——一种由姐妹病原体蛙壶菌（Batrachochytrium dendrobatidis，Bd）和蛙形短尾蝾螈壶菌（Batrachochytrium salamandrivorans，Bsal）引起的角蛋白相关的两栖动物传染病。我们专注于它们在欧亚大陆的气候-病原体关系，这是它们地理分布唯一重叠的地区。欧亚大陆拥有这两种病原体的入侵区和本地区，以及它们共存的自然栖息地，这使其成为研究它们环境生态位相关性的理想区域。我们对气候变化将如何影响它们的分布的理解，因 Bd 和 Bsal 在亚洲和欧洲的气候关联和生态位特征的差异而得以拓宽。这些知识对未来不同地区疾病的传播具有潜在的保护意义。
我们使用生态位分析量化了欧亚大陆 Bd 和 Bsal 之间的环境生态位重叠。结果表明，它们的生态位存在部分重叠，Bsal 有独特的 4%非重叠值，这表明它们在某些气候轴上存在隔离。Bd 能耐受更高的温度波动，而 Bsal 需要更稳定、更低的温度和更湿润的条件。对它们的现实气候生态位（Realized Climatic Niches，RCNs）向未来条件的预测显示，与 Bsal 相比，Bd 在亚洲和欧洲的适宜范围（Suitable Range，SR）都有更大的扩张，它们的中心也朝着不同的方向移动。值得注意的是，亚洲两个病原体的高适宜区预计将大幅缩小，特别是在极端气候情景下。在欧洲，它们预计将显著扩张。
气候变化将对两栖动物宿主产生影响或增加疾病风险，特别是在欧洲。鉴于这两种病原体在可用气候梯度上共享生态位空间，就像欧亚大陆已经由于气候变化而导致范围扩大和生态位重叠增加所见证的那样，我们预计 Bsal 目前不存在但有蝾螈存在的地区，以及 Bd 已经流行的地区，可能有利于 Bsal 的传播。
