There can be very few biologists who don’t shudder at the thought of a Cane Toad (Rhinella marina) invasion and none more so that biologists working on islands or biologists working with frogs. So what about biologists working with a critically endangered frog (Mountain Chicken Frog – Leptodactylus fallax) on an island? It’s pretty much the worst case scenario, below the arrival of the chytrid fungus. But being as Cane Toads are chytrid vectors cane toad invasions and chytrid arrival can be seen as synonymous in some respects.
The arrival of chytrid to Dominica in 2002 is not related to Cane Toads, that we know of. In fact the Cane Toad is not established on Dominica and it is one of last of the Caribbean islands still holding back the tide, so far. But as they say, time and tide wait for no man and Dominica is certainly not immune from the Cane Toad. In 2014 approximately 20 Cane Toads were discovered in Dominica, either at the port or in a storage yard in a valley east of the capital of Roseau.
It is believed that these toads either came in on a shipment of parts for a Hydroelectrical plant then moved to the storage yard, or came in another way and they found their way into the electrical plant parts. Several toads were captured at both locations and subsequently euthanized, it was then believed this invasion event was over. However, in April 2016, when I was there, 2 more Cane Toads were found in the Power plant where said equipment was moved to. One was found alive and immediately brought to the Dominican Forestry, Parks and Wildlife Division where it was tested for chytrid (results were not conclusive) and euthanized. Shortly after a second dead individual was found in the same location. The Dominican Mountain Chicken Project team rallied and did surveys of the local area, including using a recording of a male Cane Toad to illicit a response. I was even granted permission to stay in a neighbouring hotel over night for free to survey the area. Thankfully nothing was found, no adults, no juveniles, no calling and no tadpoles or spawn.
We also canvased the local neighbourhood and did a presentation at the community centre, to spread the word and get eyes on the ground. They reported no sighting as well. So it seems on this occasion the island of Dominica was lucky and hopefully this was not a second invasion event just the stragglers left from the first event in 2014, but something seems to be preventing the spread of Cane Toads to the Dominica, probably the geothermal activity of the area where they were found. Whatever it is let’s hope it continues.
Daniel J Nicholson MRes, B.Sc(Hons).