Davies' tree frog
There are fewer Davies' tree frogs than there were.  The IUCN Red List says they are a vulnerable species.  Scientists say there are fewer Davies' tree frogs because human beings have changed their places where they live from forests, because of predators, and because there are not enough Davies' tree frogs in one place for them to find unrelated partners and make healthy offspring.  They also think the fungus disease chytridiomycosis could kill Davies' tree frogs but no scientist had seen any frogs sick with it as of 2007.