New Chytrid Fungus in Europe: Clear and present danger to salamanders in US

Mass global extinctions of anurans (frogs and toads) have been an issue of conservation concern for several decades. You’ve likely seen the pictures of deformities and heard stories of beloved ponds gone suddenly silent. However, salamanders, the longer cousins of frogs and toads, have generally fared better.

Like anurans, salamanders are threatened by many human activites, including habitat loss and fragmentation, climate change, illegal collecting, and agricultural chemicals. However, generally salamanders have not been declining at the same rate as anurans. A large reason for this is that salamanders are much more resistant to the fungal pathogen Batrachochytrium dendrobatidis (Bd; AKA chytrid). When Bd sweeps through an anuran population, particularly when it occurs synergistically with environmental stressors such as novel temperatures and chemicals, mass anuran die offs are left in its wake. So far, this has generally not been the case for salamanders.

However, there is a new fungal pathogen lurking in Europe which may pose a large threat to salamanders in the US: Batrachochytrium salamandrivorans (Bs). Likely originating in Asia, a recent study in Science strongly suggests that Bs was introduced to Europe via human and animal traffic. Bs has been blamed for the local extinction of many Fire Salamander populations in northern Europe, with a 96% mortality rate. There are real fears about consequences for New World salamanders if/when Bs reaches the Americas (for more on Bs).

In short, Bs is not a load of BS.

So why should I care? What have salamanders done for me lately?

Actually, a lot. Despite their small stature and generally cryptic nature, salamanders play a large role in their ecosystems. Dr. Carola Haas sums it up nicely in a comment to an OpEd in the New York Times:

“[Salamanders] make up more biomass than all birds combined or all small mammals combined–you just don’t see them because they are mostly under logs or rocks or underground. The Appalachian mountains are known as a center of diversity for salamanders. If you don’t value biodiversity itself, you should value the ecosystem services they provide you. They play major roles in forest nutrient cycles. If ALL of the salamanders were lost at once, our timber industry may suffer because of reduced nitrogen inputs into the soils. We would see declines in many animals that feed on them, including important game species such as wild turkeys, and songbirds that also help control insect populations.”

Salamanders, which individually often weigh only a handful of grams, make up more of the biomass of forests than the meso- and macrofauna more often considered. In a recent paper (Semlitsch et al 2014), it was estimated that there are 7300 – 12900 salamanders per hectare in the Ozarks. So if there was a soccer field in the middle of the Ozarks, 5200 – 9300 salamanders would likely be under it. As Dr. Haas notes and the Semlitsch et al. study documents, that’s a tremendous reservoir or nutrients. If you like healthy forests, you should also root for healthy salamander populations.

So what is there to be done?

Unlike the Bd epidemic, which was not discovered until long after anuran extinctions had begun, we may be a half a step ahead of Bs. However, quick action is required. In an OpEd in published in the New York Times over the weekend, Drs. Karen Lips and Joseph Mendelson III suggest a four prong approach:

  1. The Fish and Wildlife Service should block the importation of potential Bs reservoirs (through use of the Lacey Act)
  2. Congress should improve Invasive Fish and Wildlife Prevention Act which would improve the ability of the Fish and Wildlife Service to monitor and control invasives, including diseases.
  3. Animal importers should voluntarily stop importing animals
  4. Educational campaigns to spread awareness
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