This species occurs in several localities in extreme northern Madagascar, including Windsor Castle, Joffreville, Ambohotsimiely, Andranovondronina, Ankitsakalaninaomby, Antsiranana, Anjiabe, the island of Nosy Hara, Ambatomenavava (Antomboko), Ambodimanga (Ambodimanga, Mahatsijo), Andoajampoana (Ambovomamy), Andranotsymaty (Tsimanankaratra, Vinay, Menagisy), Ankitsakalaninaombi (Ankitsakalaninaombi*), Antongombato (Ambinay, Analamandro, Analamanga, Anketrabe, Ankiabe, Antamotamo, Antomboko, Antongombatobe, Antsiasia, Lamerouge, Maleza, Parchuite, Tegnantsahampano), Antsahampano (Antsahampano), Daraina (Daraina*), Francom (Francom), Ivovona (Antsakoamaro*), Montagne des Francais (Andranomangitra*, Anosiravo*, Bekamankuri*, Vovo*), Mahavavona (Mangatokona*), Mangoaka (Andohonymangoko*), Montagne d'Ambre National Park (Andranobaribe) (A. Crottini pers. comm. December 2016) and Fôret d’Ambre Special Reserve (D'Cruze et al. 2008).
On the island of Nosy Hara (about 115 hectares), the species persists along one very small temporary stream in an area of only about 10 hectares. Genetic studies indicate that it is native there, isolated by the rise of sea levels, which demonstrated its adaptability and ability to survive in small subpopulations with low genetic variability of long periods of time (Crottini et al. 2012).
Two morphotypes are currently known: a green morphotype and a black one (localities with asterisk), that occupy slightly different ecological niches (Crottini et al. 2012). An isolated population closely related with Mantella viridis is known from Ankarana. Some individuals of this population are known to share the same mitochondrial haplotype with population of the typical M. viridis (Crottini et al. 2012).
There are records from 5 to 959 m Asl, though most records are below 300 m Asl and its EOO is 969 km2.
Habitat and Ecology
It is a terrestrial species of deciduous dry forest on karst landscape, usually found near temporary brooks and streams, where it breeds. It has been found in a range of secondary and disturbed habitats such as villages and draining channels along roads, and large subpopulations have been found in mango plantations with large irrigation ditches (Mercurio and Andreone 2008). This indicates that the species has good adaptability to different environments (Mercurio and Andreone 2008), however it does require shade and good vegetation cover.
It is a locally common species, but due to ongoing decline in the extent and quality of the habitat the population is suspected to be decreasing. The population is also believed to be severely fragmented as there is a viable subpopulation surviving on Nosy Hara.
The main threat is habitat loss, due to the impacts of fires, selective logging and the collection of firewood, and livestock grazing. It is also affected by the subsequent permanent drying out of smaller streams following forest loss. It has been recorded in the pet trade in relatively large numbers, although this is now greatly reduced.
Species in this genus have tested positive for Batrachochytrium dendrobatidis (Bd), however currently there have been no negative effects observed within amphibian populations in Madagascar suggesting the Bd strain has a low virulence level (Bletz et al. 2015).
This species has been recorded from the Fôret d’Ambre Special Reserve (D'Cruze et al. 2008), the new protected area of Montagne des Français, and Montagne d'Ambre National Park (Crottini et al. 2012). It is listed on CITES Appendix II and is maintained in captivity in several facilities outside Madagascar. The export of this species for international trade has been suspended since 2010, and this was continued in 2013 after studies were carried out to investigate whether trade should be reopened (CITES 2013).
Increased protection and maintenance of the remaining habitat is needed. Any future trade in this species should be carefully regulated.
Research is needed to establish the taxonomic status of populations to the southwest of the type locality. Further research is essential to fully understand the distribution, origin, type and virulence of Bd lineages found in Madagascar (Bletz et al. 2015).
Red List Status
Listed as Endangered because its extent of occurrence (EOO) is 969 km2, its distribution is severely fragmented, and there is continuing decline in the extent and quality of its habitat.
For the purposes of this assessment both the western and eastern subpopulations are considered to be this species (see Crottini et al. 2012).
IUCN SSC Amphibian Specialist Group 2017. Mantella viridis. The IUCN Red List of Threatened Species 2017: e.T57451A48704427. http://dx.doi.org/10.2305/IUCN.UK.2017-2.RLTS.T57451A48704427.en .Downloaded on 23 February 2019