Tuesday, September 26, 2023

[Botany • 2023] Most of the World's Largest Flowers (Genus Rafflesia) are now on the Brink of Extinction


Map showing the diversity in the genus Rafflesia across the Malesian Floristic Region.
 Photos/illustrations credits: Indonesia (Rafflesia arnoldiiR. bengkuluensis – AB Tobias; R. gadutensis – Septian Andriki; R. hassletii – Jeremy Holden; R. micropylora – Jan Vrsovsky; R. patma – BRIN; R. rochussenii – BBTN Gede Pangarango);
 Malaysia (Rafflesia azlaniiR. cantleyiR. kerriiR. tiomanensis – Siti-Munirah MY; R. priceiR. keithii – CJ Thorogood; R. tuan-mudae – Anthonia Chia);
Philippines (Rafflesia aurantia, R. lobataR. manillanaR. mixta – drawn by ABT based on photos of Danilo S. Balete, Renee Galang, SINP PAMO and CENRO Tubod; R. banaoana, R. consueloaeR. baleteiR. banahawensisR. panchoana – AB Tobias; R. leonardi – Erwin Agbayani; R. mira – Celine Murillo; R.speciosa – PL Malabrigo; R. schadenbergiana – Ramil Alcala; R. verrucosa – Sidic Nobair);
Base map by Gerald Eduarte.

in Malabrigo, Tobias, Witono, Mursidawati, Susatya, ... et Thorogood, 2023.

Abstract
 Societal Impact Statement: 
Rafflesia is the genus that contains the world's largest flowers. Despite their global appeal, most of the 42 known species are now at risk of extinction. Urgent action is needed to protect these remarkable flowers. A combined approach to conservation is recommended, including a greater level of habitat protection and support for local community action groups. Rafflesia is a suitable new icon for conservation in the Asian tropics.

Summary: 
The genus Rafflesia, which includes the world's largest flowers, has aroused curiosity among scientists for centuries and features prominently in local culture across Southeast Asia. The plant has long been used in ethnobotanical medicine and, more recently, as a source of revenue from ecotourism. But despite its acclaim, Rafflesia remains poorly understood in many respects. Taxonomy is disputed, new species are described each year, and the plant has proven recalcitrant to cultivation. This has hindered conservation, and most of the 42 known species are now severely threatened, yet only one is listed by the International Union for Conservation of Nature (IUCN). We estimate that 60% of Rafflesia species face a severe risk of extinction (equivalent to Critically Endangered [CR]). Moreover, we predict that at least 67% of known habitats fall outside protected areas, exacerbating their vulnerability. Alarmingly, recent observations suggest taxa are still being eradicated before they are even known to science. We present recent scientific discoveries and probable extinctions and highlight case studies of conservation success, with a focus on the role of local people. We propose a multi-pronged conservation approach combining strengthened taxonomy, ex situ propagation, ecotourism, and an extension of protected areas. We suggest action devolved to local communities and awareness campaigns linked to social media networks will be crucial outside of protected jurisdictions. Finally, we propose to establish Rafflesia as a new icon for plant conservation in the Asian tropics. A combined approach might just save some of the world's most remarkable flowers, most of which are now on the brink of being lost.

Keywords: conservation, ethnobotany, Flora, Malesiana, parasitic plants, threatened species

Map showing the diversity in the genus Rafflesia across the Malesian Floristic Region.
 Photos/illustrations credits: Indonesia (Rafflesia arnoldiiRafflesia bengkuluensis – AB Tobias; Rafflesia gadutensis – Septian Andriki; Rafflesia hassletii – Jeremy Holden; Rafflesia micropylora – Jan Vrsovsky; Rafflesia patma – BRIN; Rafflesia rochussenii – BBTN Gede Pangarango);
Malaysia (Rafflesia azlaniiRafflesia cantleyiRafflesia kerriiRafflesia tiomanensis – Siti-Munirah MY; Rafflesia priceiRafflesia keithii – CJ Thorogood; Rafflesia tuan-mudae – Anthonia Chia);
Philippines (Rafflesia aurantia, Rafflesia lobataRafflesia manillanaRafflesia mixta – drawn by ABT based on photos of Danilo S. Balete, Renee Galang, SINP PAMO and CENRO Tubod; Rafflesia banaoana, Rafflesia consueloaeRafflesia baleteiRafflesia banahawensisRafflesia panchoana – AB Tobias; Rafflesia leonardi – Erwin Agbayani; Rafflesia mira – Celine Murillo; Rafflesia speciosa – PL Malabrigo; Rafflesia schadenbergiana – Ramil Alcala; Rafflesia verrucosa – Sidic Nobair);
Base map by Gerald Eduarte.
 

Pastor Malabrigo Jr., Adriane B. Tobias, Joko Witono, Sofi Mursidawati, Agus Susatya, Mat Yunoh Siti-Munirah, Adhityo Wicaksono, Reza Raihandhany, Sarah Edwards and Chris J. Thorogood. 2023. Most of the World's Largest Flowers (Genus Rafflesia) are now on the Brink of Extinction. PLANTS, PEOPLE, PLANET. DOI: 10.1002/ppp3.10431