The British Herpetological Society

Golden Mantella Frog

A three partner collaborative project studying the conservation and sustainable utilization of  the Golden Mantella (Mantella aurantiaca) of Madagascar.

Status Update 2020 :  Successfully Completed Project 

 

This frog is a threatened species and is found only in the district of Moramanga in Eastern Madagascar; within its restricted range, the species is subject to collection for the international trade and habitat degradation due to mining, and the conversion of breeding ponds into rice fields. This project  represents a collaboration between BHS Captive Breeding Committee, the University of Kent (DICE) and the local Madagascan conservation organization Madagasikara Voakajy; also, we are delighted that the project has attracted matching funds from the UK Government's Darwin Initiative.

A conservation strategy was developed for the species in 2010, and included habitat protection, relocation of frogs from ponds affected by mining, captive breeding, and sustainable utilization of wild populations; we believe that our project will make a real contribution to this conservation strategy.

 Conservation and Sustainable Utilization of the Golden Mantella: Survey of Breeding Sites in Mangabe, Madagascar

Background:

Madagasikara Voakajy is a Malagasy organisation created in 2005 to promote the conservation and sustainable use of Malagasy ecosystems, habitats and species, by mitigating key threats through targeted actions and applied research, for the benefit of Malagasy people. Its activities are focused on endemic and threatened species, for instance the golden mantella frog, Mantella aurantiaca, a Critically Endangered species under the IUCN RedList.

The golden mantella frog is found only in the district of Moramanga in eastern Madagascar. Within its restricted range, the species is subject to collection for the international trade and habitat degradation due to legal and illegal mining, and conversion of breeding ponds into rice fields. A conservation strategy for the species was developed in 2010 (Randrianavelona et al. 2010), and included habitat protection, relocation of frogs at ponds affected by legal mining, captive breeding, and sustainable management of the collection. It is expected that golden mantella populations will be equitably, legally and sustainably managed.

In Mangabe area, Madagasikara Voakajy identified 50 ponds, 31 of which have confirmed golden mantella populations. Since 2012, there is a harvesting quota of 550 golden mantella frogs that Madagascar can export annually on the international trade. Yet, Madagascar has to develop a Non-Detriment Finding, and to prove that harvests are sustainable to maintain this quota. To do so, collection sites need to be identified appropriately.

Aim and objectives:

This project aims to update the status of golden mantella breeding ponds in Mangabe. Surveys will (i) confirm the presence/absence of the species in the ponds, (ii) estimate population sizes in each pond and (iii) assess habitat quality. Ultimately, this project will allow earmarking harvesting sites for the international trade quota.

Methods:

Presence/Absence

Ponds will be visited three to five times by a team of researchers from Madagasikara Voakajy and members of the local communities between November 2013 and January 2014, the peak season of M. aurantiaca activity. There will be an interval of at least three days between the visits. When presence of the golden mantella is confirmed, only three visits will be carried out. Population size will be estimated at each visit. We will do up to five visits for sites where golden mantella is not found to confirm absence.

Population size estimates

Golden mantellas observed in a quadrat of 5m x 5m will be counted. Each quadrat has a specific identity and will be surveyed systematically following specific direction to avoid double counting. Three to 75 quadrats will be set up according to the size of the pond. Quadrats will be distributed in the ponds and the adjacent forest. As golden mantellas are often difficult to observe but have distinctive vocalization, abundance will also be estimated based on the calls. After the direct counts, number of mantellas heard from the quadrat will also be estimated.

Habitat assessment

Habitat assessment will be done following the quadrats of 5m x 5m, the same as we mentioned to determinate the population size or the number of mantellas. Therefore, the quadrats will be selected across the topography from the ponds at the bottom, the slope area to the ridge or crest of the forest. The quality of the habitat will be assessed using the methods described by Randrianantoandro et al. (2008): the number of standing, fallen and cut trees, fern, tree fern, Pandanus spp., Dracaena spp. cow's feces will be counted; and the litter depth, diameter of tree trunk will be measured using tape measure. Using a 1 m stick marked with cm graduations, we recorded whether there was contact with ground vegetation in four height categories (0–0.24, 0.25–0.49, 0.50–0.74 and 0.75–1.0 m) every 10 cm along two 5 m lines with the perch at the centre. The percentages of plants, forest and water covers in the pond, as well as the canopy cover, litter cover, and understorey cover will be estimated using the matrix from the method of Oldham (2000). The slope will be measured with clinometers. The quadrats will be classified as occupied or not by mantellas during the data. Variables such as temperature, humidity, pH, conductivity and luminosity will be collected especially for microhabitat, refuge or water used or not by mantellas.

Wider relevance of the project:

This project will complement existing collaborative research being carried out by Madagasikara Voakajy and the Durrell Institute of Conservation and Ecology at the University of Kent. This work is focusing on providing science-based data to inform the CITES decision-making processes in Madagascar, and is funded by the British Government's Darwin Initiative. Previous research (also supported by BHS) resulted in a new export quota for the chameleon Furcifer campani – a species that previously came under a trade ban. We hope that the proposed research will improve the knowledge base for a similar reassessment of the quota for Mantella aurantiaca. To this end, DICE is committing resources to evaluate the current quota formula, carry out population viability analyses of mantellas, advise on captive breeding protocols and assist Madagasikara Voakajy with spatial modelling of mantella habitats.