Olga Ramilijaona Ravoahangimalala

The perfect invader: a parthenogenic crayfish poses a new threat to Madagascar’s freshwater biodiversity

In 2007 an unusual crayfish found in food markets in the capital of Madagascar was preliminarily identified as Procambarus ‘Marmorkrebs’: a new world taxa and the only decapod known to reproduce by parthenogenesis. We present information on the identity, distribution and ecology of this recent invader and attempt to evaluate the threat it poses to Madagascar’s biodiversity and to livelihoods. The species appears to be currently limited to the area close to Antananarivo, but is being sold alive on major transport routes. We present molecular evidence of its taxonomic relationships and confirm that the Procambarus present in Madagascar is indeed the parthenogenic taxa. We investigate its reproductive ecology and find Procambarus ‘Marmorkrebs’ to have an extremely high fecundity; more than six times that of the native crayfish Astacoides. The limited evidence we have suggests that this species poses a serious threat to freshwater biodiversity and that it is likely to damage human livelihoods (through its impact on fishing and possibly rice agriculture). More research is urgently needed but in the meantime action is needed to reduce the rate of spread before it is too late.

Distribution and Population Density of the Black-Eared Malagasy Poison Frog, mantella Milotympanum Staniszewski, 1996 (Amphibia: Mantellidae)

We provide first data on the natural history of a poorly known species of frog from Madagascar, the black-eared Malagasy poison frog, Mantella milotympanum. Although this species has been intensively collected for the pet trade, not even one precise locality was published until 2003. We here provide further distribution records north and south of the known locality Fierenana, but the encountered populations showed variable colour and patterns intermediate between M. milotympanum and M. crocea, thus supporting the hypothesis that these are conspecific colour morphs, and that M. milotympanum might be a junior synonym of M. crocea. Intensive fieldwork at one site next to Fierenana, in February 2003, yielded some data on population structure and density. Snout-vent lengths ranged from 16–24 mm, weights from 0.4–1.4 g in adults, with only few subadults and no juveniles found. The population density, estimated by mark-recapture, was about 470 individuals per ha, which is a quite high density, taking into consideration that this population had probably been under commercial exploitation in the past. We propose that some of the forests in the Fierenana area should be included in the planned extension of Madagascar’s network of protected areas, but a controlled and sustainable exploitation should be allowed in these reserves in order to gain the support of local communities.

Raising Awareness of Amphibian Chytridiomycosis will not Alienate Ecotourists Visiting Madagascar

Chytridiomycosis (Bd) is contributing to amphibian extinctions worldwide but has so far not been detected in Madagascar. The high likelihood for Bd to spread to the island and efface this amphibian diversity and endemism hotspot requires respective conservation policies to be developed. Bd could be introduced by the large number of tourists that visit protected areas; therefore, increasing awareness among tourists and encouraging them to participate in safety measures should be a priority conservation action. However, concerns have been raised that tourists would not be able to distinguish between an amphibian disease harmless to humans and emerging diseases that would imply a danger for human health, invoking a negative image of Madagascar as an ecotourism destination. We evaluated whether informing tourists about this infectious animal disease would cause health scare and diminish trip satisfaction. Based on 659 respondents we found that most ecotourists favored to be informed about Bd and were proactive about participating in prevention measures, refuting previous concerns.