21 Feb 2017
Discovering the remarkable nature of São Tomé and Príncipe
There are undoubtedly discoveries to be made, with the invertebrate and marine biodiversity of the archipelago particularly understudied. Each new expedition to the islands uncovers species new to science.
By Merlin Veron, Synchronicity Earth
Synchronicity Earth is a UK charity which, on the basis of its research, aims to identify and increase support for high-priority conservation action globally.
On first inspection, the São Tomé Grosbeak Crithagra concolor might appear drab, unassuming, maybe even unremarkable. But first impressions can be deceiving. It is in fact one of the most endangered bird species on the planet, and was not sighted for over 100 years between 1890 and 1991, when it was rediscovered in the forests bordering Rio Xufexufe in the south-west of São Tomé.
Sightings of this finch since its rediscovery have been intermittent – the species was only photographed for the first time in 2006 and to date has still only been seen by a handful of non-Santomeans. BirdLife estimates a tiny extant population ranging from 50-250 individuals.
As well as its rarity, the taxonomy of this species is also fascinating and distinct. The São Tomé Grosbeak may be almost unique amongst bird species in that genetic studies suggest it evolved in sympatry with the Príncipe Seedeater Crithagra rufobrunnea, another endemic species.
Sympatric speciation occurs where two separate species evolve from a common ancestor without being geographically isolated from one another. This could happen if, for example, environmental conditions heavily favoured large individuals and small individuals, but not medium-sized ones, thus driving the evolution of two differently sized species.
The São Tomé Grosbeak is in fact the world’s largest canary with a ‘bullish’ head and powerful bill which rivals that of a Hawfinch – it dwarfs the Príncipe Seedeater and is almost twice its size, however questions still remain over what exactly drove the separation of these two species.
In fact if there is something unremarkable about the São Tomé Grosbeak it is that it inhabits an archipelago awash with other astonishing flora and fauna. The islands of São Tomé and Príncipe are located approximately 250km off the coast of Gabon, and as such have experienced somewhat of a ‘goldilocks effect’, in that they are close enough to the rich tropical forests of West and Central Africa to allow some populations to reach the islands, but distant enough so that once they do these populations become isolated and follow a distinct evolutionary trajectory.
Including the São Tomé Grosbeak there are a total of 28 endemic bird species on the islands, meaning a greater number of endemic species than the Galapagos Islands in an area approximately an eighth of the size. Amongst these species are the world’s largest Giant Sunbird Dreptes thomensis, Weaver Ploceus grandis and São Tomé Oriole Oriolus crassirostris, and its smallest Dwarf Ibis Bostrychia bocagei, a species which is also critically endangered and restricted to the primary forests of Obo Natural Park.
As well as endemic avifauna, the islands also harbour 1,230 described plant species, approximately 15% of which are endemic, as well as 19 butterfly species found only on this archipelago. The islands even hold 7 endemic amphibians, something which remains somewhat of a mystery considering amphibians’ known intolerance of salt water and the fact that as volcanic islands São Tomé and Príncipe were never connected to mainland Africa. There are also undoubtedly more discoveries to be made, with the invertebrate and marine biodiversity of the archipelago particularly understudied, with each new expedition to the islands uncovering species new to science.
The value of the biodiversity present on these islands has been recognised through a number of designations. Príncipe is recognised as a UNESCO Biosphere Reserve, both islands host KBAs and IBAs where primary habitats remain, the Tinhosas Islands which host more than 280,000 breeding seabirds are recognised as a Ramsar site, and the presence and critically endangered nature of the São Tomé Grosbeak, the Newton’s Fiscal Lanius newtoni, and the Dwarf Ibis triggered the recognition of Obo Natural Park as an Alliance for Zero Extinction site.
These designations all point to the importance of conserving this archipelago’s remarkable biodiversity, however historically habitat loss, in parallel with other threats, has driven many of the islands’ species towards extinction. Habitat destruction was rife during the Portuguese colonial era, with the islands first a centre for sugarcane production, and latterly coffee and cacao.
Whilst this led to widespread forest clearance, the primary, secondary and even shade forests on the islands continue to provide key habitats, but face new threats in the form of illegal logging, agro-industrial concessions and residential and commercial developments.
However, one particular threat which continues to hamper efforts to conserve biodiversity is a lack of local conservation capacity and community engagement. This is something which BirdLife has partnered with NGOs working in São Tomé and Príncipe to address, recognising that conservation begins with local people.
BirdLife has had a presence on São Tomé since 2006, with the conservation of the three critically endangered endemic bird species a key focus, culminating in the production of a species action plan produced in collaboration with the Santomean Government and local NGOs. One key pillar of BirdLife’s work has however focused on developing the capacity of civil society and raising awareness amongst the local population of the unique and threatened status of São Tomé’s biodiversity.
Studies have shown the low level of environmental education in São Tomé, particularly amongst rural populations. To try to instil an awareness and sense of pride in the biodiversity which the islands harbour BirdLife has worked with Portuguese partner SPEA (BirdLife Portugal) and the RSPB (BirdLife UK) to organise community meetings and collaborated with local artists to paint large murals of the critically endangered species in five villages.
Work is also underway in collaboration with Portuguese NGO Oikos to engage local musicians in producing a music and dance-based environmental awareness campaign celebrating São Tomé’s biodiversity and to engage with young people through a schools education programme and the establishment of nature clubs in the buffer region of Obo Natural Park.
The aim of these programmes is to increase awareness amongst the Santomean population about the importance of its biodiversity and the need for its conservation to protect livelihoods and environmental services. BirdLife hope to inspire future generations of conservation leaders on the island who can fill gaps in knowledge, identify key actions to protect species and ensure that the islands’ natural heritage is considered in decisions about its future development, meaning conservation is locally led.
Through engagement comes empowerment. This work is just one component of the activities needed to conserve São Tomé’s unique environment; and boosting local enforcement capacities, continuing to conduct scientific research to expand knowledge, and developing sustainable livelihood and development opportunities will also be integral.
However, where local people become engaged and invested in conservation, the future of enigmatic endemics such as the São Tomé Grosbeak will surely be more secure.