Kihansi Spray Toad

I pass a signboard of the Kihansi Wildlife Research Station. It says "Kihansi Spray Toad Breeding Facility". What the heck? Here, in the middle of nowhere? Out of curiosity I turn back and ask for a visit. Granted.

Felix the station supervisor and his volunteer Yoel are super welcoming and within minutes I dive deeply into the extinction history of this very "spray toad". It was once endemic to the Kihansi river flowing down in several waterfalls from the Udzungwa escarpment behind us. The species was strongly depended on the water spray in vicinity of the falls. When around 1996 a hydropower plant has been built in the upper areas, the water flow declined from 16 m³ to 2 m³ per second which resulted in much less waterfall spray. The following vegetation change among other factors lead to rapid vanishing of the whole toad population which was specialized on the humid environmental conditions, to be found in this very gorge only.

Now, here we are at the breeding facility which conducts research on how to re-establish a stable population. The tiny yellowish toads are live-bearing and just give birth to 3-5 youngsters each iteration. The eggs are fertilized inside of the mother’s body and need around 3 months to hatch and to be "raised". Already these parameters make the species very fragile. I learn how at this breeding facility the young toads are fed with Collembola (springtails) and the adults with Drosophila (common fruit fly) and crickets, all being farmed just the next door. There is also another captive population in the USA which is going to be partly transferred here soon.

It is 4 in the afternoon and Yoel spontaneously offers to hike up the steep path into the thick forest to one of the wetland areas, the former toad habitat. After the environmental impact assessment, the power plant operator TANESCO has been made responsible to maintain the gorge infrastructure for the government being able to conduct research around the resettlement of the toads. They have installed artificial sprinklers to imitate the humid environment 😅. The first toad release experiments here have not been successful and some of the following research questions are still open: Which influence does natural food have in contrast to artificial feeding? Which change in vegetation has the biggest impact? How does the immune system of toads raised in captivity deal with diseases such as chytrid fungi (the former population must have been able to withstand)? Is there an inbreeding depression on the population? A nice playground for students! There is still one rather intact wetland area left upstream which is promising for future release experiments.

The three of us spend our evening at Kihansi Social Club which hosts all the power plant workers and also fills the gap of being the only place to hang out in this region. Felix got a Master’s degrees in natural resource management in Australia and one in aquaculture in Belgium. For his thesis he went to Vietnam. Yoel graduated with a Bachelor in biotechnology and laboratory science.

For the night I get a room in the research station’s guest house 😎. With a burning heart I leave the following noon after catching up with some digital homework in this cosy atmosphere.Leer más