Mr. Toad's Wild Fungi: Fungal Isolate Diversity on Colorado Boreal Toads and their Capacity for Pathogen Inhibition.

The amphibian skin pathogen () has caused an ongoing biodiversity crisis, including in the locally endangered Colorado boreal toad (). Although researchers have investigated the bacteria living on amphibian skin and how they interact with , there is less information about fungal community members. This study describes (1) the diversity of culturable fungi from boreal toad skin, (2) which subset of these isolates is -inhibitory, and (3) how affects these isolates' growth and morphology. Most isolates were from the orders Capnodiales, Helotiales, and Pleosporales. Of 16 isolates tested for -inhibition, two from the genus and three from inhibited . Fungal growth in co-culture with varied with weak statistical support for . (isolate BTF_36) and cf (isolate BTF_60) (p-values = 0.076 and 0.092, respectively). Fungal morphology remained unchanged in co-culture with , however, these results could be attributed to low replication per isolate. Nonetheless, two fungal isolates' growth may have been affected by , implying that fungal growth changes in co-culture could be a variable worth measuring in the future (with higher replication). These findings add to the sparse but growing literature on amphibian-associated fungi and suggest further study may uncover the relevance of fungi to amphibian health and infection.