Uncovering the secrets of Príncipe’s mysterious rainforests

Posted on by Jessica Walker
Two years of research efforts on Príncipe have transformed our knowledge of this tiny island’s diverse flora, bringing the total of plant species to 415. These field surveys represent a major botanical undertaking and led to 45 new records for the island, including eight species that are new to science.

Príncipe is a remote volcanic Island within the São Tomé e Príncipe archipelago, off the west coast of Africa. The complex topography of the island was hypothesised to be home to threatened tree species, but until recently, was one of the last botanically unknown places on earth.

The captivating landscape of Príncipe Island is far from homogenous: Elevated areas in central Africa are often biodiversity hotspots with unique assemblages of plant species. Credit: MBG/Tariq Stévart.

The first attempt to classify Príncipe’s forest

As part of the GTC, Fauna & Flora International, Fundação Príncipe Trust, the Missouri Botanical Garden (MBG) and the University of Coimbra among others, have conducted 13 field expeditions involving transect surveys and plant collection. This was underpinned by significant training sessions, to allow the researchers to make the most of their ventures into the dense tropical rainforest.

The surveys gathered enough data to begin an assessment of the conservation status’ of potentially threatened tree species. Based on preliminary analyses, 29 species are rare, endemic, or new to science, and at least seven of these are proposed as threatened based on IUCN Red List Criteria. Strephonema sp., one of the two species known locally as ‘Gôgô’ for instance, is considered endemic and is currently proposed as Endangered (according to the IUCN Red List categories); it grows to enormous heights and provides wonderful nesting sites for many birds, including grey parrots and endemic owls.

Dedicated field researcher measuring a huge and very old Strephonema sp.. It is currently considered endemic to Príncipe and will potentially be classified as Endangered on the IUCN Red List. Credit: MBG/Tariq Stévart.

Identifying conservation hotspots

One of GTC’s goals is to help the local authorities to identify important areas for targeted conservation. The most important habitat for conservation is the ancient coastal lowland forest around Rio Porco. As most primary forest in the region has been degraded due to human activities near the sea, this is probably one of the last intact coastal forest ecosystems in the Gulf of Guinea.

These mature forests are home to fabulous biodiversity, including the endemic Príncipe shrew (Crocidura fingui) and 33 known bird species. More than 50% of the island’s birds are endemic, such as the Príncipe Thrush (Turdus xanthorhynchus) and even an as yet undescribed Scops Owl species, discovered in June 2016.

The sub montane forest of Pico do Príncipe at around 600m is also of importance since it possesses a unique flora, and many species which are still yet to be identified. Both these mountainous areas and the lowland coastal forests should therefore be subject to special attention in the Príncipe Natural Park management plan.

View of the submontane forest at Pico Príncipe from the research camp. Credit: MBG/Tariq Stévart.

Although the forests in the north of the island are significantly degraded, generally through conversion to plantations, the remaining forest hosts an abundance of medicinal species, which are under continued pressure from local communities. There is a pressing need to understand the threats facing these valuable species, to prevent them from disappearing altogether.

Intrepid botanists burning the midnight oil during intense field excursions. Credit: MBG/Tariq Stévart.

Future proofing Príncipe

With large swathes of forest in the north lost to agriculture and trees across the island still under threat from logging and bark-harvesting, it is the opportune time to build on these survey results to establish better protection of the island’s plant life. Beyond prioritising ways to protect the threatened tree species on Príncipe, this project has unlocked the passion and capacity of local stakeholders to protect these special forests.

The botanical training and surveys are a great reminder of how special and valuable these forests are – reinvigorating local efforts to protect what remains in the south of the island where the forest is mostly still pristine.

The immediate next steps are to complete the red listing process for the island. Reliable information on extinction risk will help to inform where in situ conservation efforts should be targeted, and which acutely threatened species need urgent action. Effective conservation action will ensure that these amazing forests and its rare and endemic flora, which make Príncipe island so special, continue to thrive for long into the future.

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