Madagascar is well-known for its endemec and peculiar amphibian fauna: more than 350 species living only there and at least other 200 which are waiting for a formal description. But habitats are going away under the deleterious actions of Homo sapiens, who is affecting the last fragments of dry and rainforests. Among the negative anthropogenic actions we may also quote the introduction of alien species. One of the last cases deals with the so-called Asian common toad, Duttaphrynus melanostictus, of which I already narrated some time ago (https://francoandreone.wordpress.com/2018/02/26/the-asian-common-toad-in-madagascar-out-of-control/). Fulvio Licata is currently conducting his PhD to study the migration, expansion and effect of this species on natutive habitats and species. One of the first fallouts of this study is the recent publication of a paper on the renowned journal Biological Invasions. In this study Fulvio documented the expansion of the invasive range of this stoad pecies, calculating the invasion spread rate, and providing estimates of abundance and habitat preferences. The distribution range showed a fivefold increase of the invaded area over 3 years, and a doubling of the rate of spread. The species appears therefore to be a severe invasor and we are just waiting that it enters within forest reserves. We do not know yet which will be the effects on the amphibians and other animals living there. the risk is that potential predators (snakes, mammals, birds) could become killed when trying to ingest the toad, due to its toxicity. This was already showed in the parallel invasion occurred/ing in Australia by the cane toad Rhinella marina. The Asian toad has all the potentialities to threaten the already delicate fauna of Madagascar. Next years will be extremely crucial in defining the impact of this amphibian.
Licata, F., Ficetola, G.F., Freeman, K. et al., 2019. Abundance, distribution and spread of the invasive Asian toad Duttaphrynus melanostictus in eastern Madagascar.Biological Invasions. https://doi.org/10.1007/s10530-019-01920-2
An individual of Duttaphrynus melanostictus: this species is spreading over Madagascar and represents a worrying threat for the endemic fauna of this island (photo by F. Andreone)