Nature in Madagascar, an island off southeast Africa slightly larger than metropolitan France, is so unusual that 82% of its plant species and 90% of its vertebrates are endemic, only occurring there. Living amidst this unique biodiversity is a population so deprived that the country’s human development index (HDI) is one of the world’s lowest, posing the challenge of harmonizing conservation with economic and social development.
A portrait of Madagascar’s biological riches as well as the main threats to nature and the conservation outlook can be found in two studies published , in the journal Science by researchers affiliated with 50 organizations around the globe, including a Brazilian biologist supported by FAPESP.
“From the conservation standpoint, Madagascar faces similar challenges to Brazil. It’s a developing country with extremely poor remote areas. Both need to work on conservation and simultaneously improve social conditions,” said Thaís Guedes, a co-author of both articles. Guedes is a researcher at the State University of Campinas’s Institute of Biology (IB-UNICAMP) with a scholarship from FAPESP.
In one of the articles, the team of researchers presents a comprehensive up-to-date review of the literature on the evolution, distribution and uses of the island’s biodiversity, showing that its plants and animals are so locally distinctive that extinction of only one species could spell the end of an entire evolutionary lineage.
“Madagascar has species that are unique in the world, but it’s far more than that. There are categories broader than species that only exist there, such as the lemurs (Lemuroidea), an entire order of birds (Mesitornithiformes) and all mantella frog species (Mantellidae) except three. Loss of one species could mean the end of an entire lineage that took millions of years to evolve,” Guedes said.
Indeed, three lineages of lemurs have already become extinct (koala, monkey and sloth lemurs), as have the island’s two hippopotamus species, the Grandidier’s giant tortoise (Aldabrachelys grandidieri) and the elephant bird order (Aepyornithidae). According to the researchers, megafauna extinctions have major implications for the functioning of the ecosystem.
The study includes updates showing that 11,516 species of vascular plants (82% endemic) and 1,215 bryophytes (28% endemic) have been described. As for terrestrial and freshwater vertebrates, 95% of the island’s mammals, 56% of its birds, 81% of its river fish and 98% of its reptiles are not found anywhere else on Earth.
Thirteen endemic species are believed to have become extinct since 1500 and 33 other extinctions are thought to have occurred in pre-historic times, probably as a result of contact with the first humans to arrive on the island.
The other article includes reflections on the decline of Madagascar’s biodiversity and points to conservation opportunities for the country. The authors believe the fact that a large proportion of the population make a living from the forests by collecting firewood or hunting is an opportunity for development based on the sustainable use of biodiversity.
Of the 40,283 plant species used by humans worldwide, 1,916 (5%) are found in Madagascar and 595 are endemic to the island. With 28 million inhabitants, 10.4% of the territory is protected by law.
“To date, the focus has been on creating protected areas and keeping people out of them as much as possible in order to reduce the impact of human activity on biodiversity. Unfortunately, this hasn’t produced the expected results, because poor communities – the vast majority of the population – need to cook and heat their homes and have no option other than to cut down trees in the existing reserves in order to get firewood,” says Alexandre Antonelli, who led both studies. A biologist from São Paulo state, Antonelli is Director of Science at the Royal Botanic Gardens Kew (Kew Gardens) in London, England (UK).
In light of these difficulties, the authors suggest the focus should be not on creating new protected areas but on restoring vegetation elsewhere in order to reduce pressure on existing conservation units. Reforestation and conservation based on scientific evidence and effectiveness are among the five opportunities listed for the country. To arrive at their recommendations, the authors interviewed researchers in Madagascar and other parts of the world, as well as talked to conservation activists and politicians.
The authors also recommend extended biodiversity monitoring and production of databases on species. In addition, they stress the need to enhance the efficacy of protection in existing areas by engaging communities and providing opportunities for training and income generation.
In this context, conservation and restoration initiatives should include landscapes and communities adjacent to protected areas. Actions to conserve forests should take into account the main causes of biodiversity loss, which include poverty and food insecurity, problems that also affect Brazil, despite the peculiarities of each country.
“It’s very important to both countries and the world that they protect their forests and restore degraded areas, which capture and store large amounts of carbon. They’re essential to combat global warming. When forests are cleared, the consequences affect the most marginalized groups in society,” Antonelli said.
The consequences of deforestation, he continued, include lack of drinking water from rivers and water tables, heightened risks of landslides in hilly areas, fewer pollinating insects to service croplands near forests and less capacity for human communities to cope with extreme heatwaves owing to lack of shade and disappearance of the chill factor fueled by evapotranspiration from forests.
“Generally speaking, our description of biodiversity in Madagascar is shaped by knowledge of plants and vertebrates. We don’t know much about invertebrates or fungi, for example,” Guedes said. “We need to sample these poorly understood groups and use multiple metrics of diversity in future studies. For both Madagascar and Brazil, we advise policymakers to take into account not only species diversity but also the evolutionary history of these places.”