After more than a century, researchers rediscover a rare begonia on a Brazilian island

cbioclimamidia
Dec 9
3 min read

By Carolina Medeiros

A recent study published in Oryx – The International Journal of Conservation by a group of Brazilian researchers presents information about an important scientific rediscovery. Begonia larorum was rediscovered after more than a hundred years on Alcatrazes Island, one of Brazil's most isolated biodiversity sanctuaries, located off the north coast of São Paulo. The study was conducted by Professor Fábio Pinheiro, from the Institute of Biology at Unicamp and associate researcher at CbioClima, and by doctoral student Gabriel Pavan Sabino.

Begonia larorum is a critically endangered species and, according to the Management Plan of the Tupinambás Ecological Station and Wildlife Refuge of the Alcatrazes Archipelago, it was listed as possibly extinct. The plant is endemic to the island and was rediscovered in 2024, after 14 expeditions to the archipelago between March 2022 and September 2024. The finding reignites conservation alerts and shows the vulnerability of species restricted to island environments.

This prolonged absence is explained by the isolation and difficulty of access to the archipelago, which combines rocky walls, increasing depth, and strict environmental protection rules. Even so, the place has already suffered intense human disturbances throughout the 20th century. There have been agricultural crops, the presence of lighthouse keepers, and military occupation marked by shooting exercises, which caused devastating fires.

The Investigation: 14 Expeditions in Search of a Botanical Ghost

Driven by the suspicion that the species might still survive in some isolated location, the expeditions to Alcatrazes Island included sweeps through dense forests, cliffs, exposed slopes, and areas highly degraded by old fires.

The first clue emerged only in February 2024, when a single sterile individual was found in the undergrowth of a forested area on the island. However, the difficulty of studying a plant incapable of flowering and fruiting led the team to an alternative strategy: ex situ propagation, that is, the creation of individuals or the conservation of genetic material outside its habitat, using management techniques in artificial environments.

In this case, cuttings initially kept in water were used, forming five clones, two of which reached the reproductive phase in a nursery. Definitive confirmation of the species came months later.

As early as September 2024, a small population of 19 individuals, 17 of which were reproductive, was located in an area of open vegetation. The plants were photographed, georeferenced, and collected to compose the first modern scientific records.

The article also gathers information about the scenario found by the researchers, which also served as a critical warning: the island has areas with invasive grasses and ferns, such as Melinis minutiflora and Pteridium esculentum, which dominate degraded spaces and increase the fuel accumulated in the soil.

This dry biomass acts as a trigger for fires. Events like this have marked the recent history of Alcatrazes, especially during the military period. In 2004, a single fire caused by training destroyed about 20 hectares of the island.

According to the researchers, for a plant with few known individuals and a restricted distribution, any disturbance can mean the extinction of the species.

Estratégias de conservação: entre o isolamento e a necessidade de ação

Os pesquisadores da Unicamp defendem a adoção de medidas urgentes para impedir que a Begonia larorum desapareça novamente, desta vez, para sempre.

As recomendações incluem:

Manutenção da proteção integral já existente no arquipélago, com controle rigoroso de acesso;
Controle ativo de espécies invasoras, reduzindo a competição e o risco de incêndios;
Programas de conservação ex situ, garantindo a reprodução e preservação genética em jardins botânicos e coleções científicas;
Estudos adicionais sobre genética, reprodução e ecologia da espécie, fundamentais para planejar ações futuras.

O artigo também destaca a necessidade de submeter oficialmente a planta à Lista Vermelha da IUCN (União Internacional para a Conservação da Natureza), fortalecendo sua visibilidade em políticas internacionais de conservação.

O estudo não significa apenas a redescoberta de uma espécie considerada extinta, revela também uma realidade mais ampla: espécies insulares brasileiras estão entre as mais vulneráveis a distúrbios ambientais, mudanças climáticas e invasões biológicas. Sem políticas robustas de manejo e conservação, redescobertas como essa podem ser exceções em meio a um cenário de perda contínua de biodiversidade.

Para os cientistas envolvidos no estudo, a mensagem é clara: há muito mais a ser descoberto nas ilhas brasileiras, e ainda mais a ser protegido.

Você pode ler o artigo científico na íntegra por meio do DOI: https://doi.org/10.1017/S0030605325000419