A biodiversity Goldmine?

What We Are Doing.

Surprisingly, São Tom? and Príncipe have remained largely unstudied since the early 19th Century work of Portuguese biologists Fea, Greef and Newton. In spite of the wonderful but preliminary stuff discovered by these early biologists, São Tom? and Príncipe have remained “off the scientific beaten path”. Historically, the islands were used as major slave entrepots by the Portuguese and were of world importance in the production of sugar, coffee and then cacao. Lying 200 to 250 km off the coast of West African coast, the islands have always been rather remote, and even to this day, there is but one flight per week from Europe to São Tom? (via Lisbon) and only a couple from Libreville, Gabon. In spite of several hundred years of agricultural efforts, fairly large amounts of original forest remain in higher elevations that were simply too steep to be cultivated by the colonials. While the birds have been studied and a preliminary flora has been published, huge portions of the biodiversity of these unique islands remain completely unknown.


Drs. Iwamoto and Drewes sampling fish. Principe GG I (D. Lin phot)


Periopthalmus A Principe mudskipper GG I (D. Lin phot)

So what we are doing is the most basic work in science; we are hiking into these remaining natural areas and surveying them to find out what species live there, what their evolutionary relationships are and where they came from. Depending upon our different specialties, we work both by day and by night, collecting, sampling, photographing, recording, etc. Most of our material is brought back to the California Academy of Sciences for study, but much also goes out to specialists around the world. As systematists, our job is to explore and sample all of the elements of the fauna and flora. When new species are discovered, we must analyze and describe them. Systematics is the fundamental discipline upon which all other biological work depends, especially including conservation efforts. You cannot save what you do not know.


Grad student R. Stoelting. Night work on Sao Tome GG I (RCD phot)


Giant gecko (H. greefii) Principe GG II (D. Lin phot)



Exclusive Economic Zone, Rep. Sao Tome and Principe.
As the title “Island Biodiversity Race” implies, there is a significant element of urgency in our work. The islands of the are about to undergo profound change, and the reason is oil. The exclusive economic zone of the Republic includes areas in the Gulf of Guinea where oil has been discovered. This means that at the very least, there will be a huge influx of revenue into this tiny republic of less than 300,000 people, and along with this revenue will come enormous pressure to expand infrastructure and a consequent burgeoning of the human population. History repeatedly shows us that such a phenomenon almost always affects natural wild areas negatively. Thus, It is our purpose to learn as much about the flora and fauna of the islands as quickly as we can, before the changes come. We hope to demonstrate to the citizens of the Republic of São Tom? and Príncipe the unique biological nature of their islands and enable them to make informed decisions down the road. We hope to show what they, and for(and for that matter, the rest of the world) stand to lose without adequate stewardship.


Kids at Santa Catarina, Sao Tome GG II (D. Lin phot)


Sao Tome GG II (D. Lin phot)

In this blog, I will describe the Third California Academy of Sciences Gulf of Guinea Expedition (GGIII) as it unfolds. Each expedition is made up of scientists chosen because their specialties are poorly known on the islands. The following URL describes our goals, the participants in the first two expeditions, and our scientific progress since the first expedition in 2001 (GGI).

PARTNERS We gratefully acknowledge the support of the Research Investment Fund of the California Academy of Sciences, the Société de Conservation et Développement  (SCD) for logistics, ground transportation and lodging, STePUP of Sao Tome http://www.stepup.st/ and especially the generosity of three private individuals, George F. Breed, Gerry F. Ohrstrom and Timothy M. Muller, for making GG III possible. http://research.calacademy.org/research/herpetology/bdrewes/




My name is Bob Drewes; I am a research biologist, and I have worked in Africa’s wild places with considerable pleasure for over 35 years. I am Curator of Herpetology at the California Academy of Sciences, the western United States’ oldest academic research institution.

Very shortly, I will be leading the Academy’s third biodiversity expedition to the remote islands of São Tomé and Príncipe which lie off the west coast of Africa in the Gulf of Guinea,. These two mountainous islands together form the world’s second smallest republic (after the Seychelles Islands). São Tomé and Príncipe are biologically unique; they are the two middle members of a four-island chain (sometimes known as the Gulf of Guinea Islands) that is the only archipelago on earth comprised of both continental and oceanic islands.

island map

Continental vs Oceanic Islands

Unlike the northernmost island, Bioko (formerly Fernando Pó) which is a continental island separated from the Cameroon coast by only 20 miles of relatively shallow water, São Tomé and Príncipe arose some 2 to 4000m up from the ocean floor and thus have never been attached to mainland Africa; this means that the ancestors of all the plants and animals that are found on the islands today must have crossed hundreds of km of deep salt water to get there (dispersal) – this only occurs over time and is successful only by random chance. The colonizers that make it and survive are then separated from their mainland founder populations and over time begin to accumulate genetic changes, a process we all know as evolution.


The forest at 1400 m. Sao Tome GG II (D. Lin phot)

In the case of São Tom? and Príncipe, there’s been plenty of time for this to occur as São Tomé and Príncipe are very old islands. It is fact that the Hawaiian Islands and the Galapagos are only about 5 million years at the oldest; compared with the Gulf of Guinea islands, these two famous and well-studied archipelagos are relative infants! Solid geological evidence tells us that São Tomé is at least 15 million years old, and Principe is more than twice that, at over 30 million years. This is a very long time for successful dispersal, long-term isolation and evolution to take place, and it has — in spades! The evidence can be found in the high numbers of endemic plant and animal species that still inhabit the higher elevations on the two islands – species that are found nowhere else in the world.


Endemic Newtons sunbird Sao Tome GG II (J. Uyeda phot)


Sao Tome, view SW from 1400 m. GG I (RCD phot)


Sao Tome fruit bat GG II (D. Lin phot)

Among the vertebrates, more than half of the 49 species and subspecies of land birds breeding on São Tom? and Príncipe are endemic, and they include the world’s largest sunbird, the world’s largest weaver and the world’s smallest ibis. Mammals make poor over-water dispersers (high metabolic rates) so as we would predict, endemic mammals are limited to a couple of bats and two shrews that have not been well studied. There are no endemic freshwater fish on the islands, but our first two expeditions yielded many more species in the rivers and streams than previously recorded. About half of the reptile species on the islands are unique to them; one of them is the largest lizard in its genus, Greef’s gecko (Hemidactylus greeffi). But most surprising of all is the presence of an amphibian fauna, especially because due to the nature of their permeable skin, amphibians almost never cross saltwater barriers; they are considered among the poorest dispersers, along with freshwater fish. Not only are six unique frog species present (we just described a new one), there is also a legless amphibian known as a caecilian that is found only on São Tom?; its nearest relative is found only in East Africa, thousands of miles away.


Sao Tome endemic caecilian “cobra bobo) GG I (D. Lin phot)


Principe giant treefrog GG I (D. Lin phot)

The invertebrate species and flora are also remarkable; so far as is known, about 14% of the flowering plants are endemic, including the world’s largest Begonia at 2 meters ! More than half of the ladybugs and spiders, 80% of the stag beetles and 2/3rds of the terrestrial snails are found nowhere else in the world; but these data are based on very limited sampling much of which was done in the late 19th Century, this is one of the reasons we are here. [Begonia ebaccata]. [bubba]


Begonia baccata Sao Tome.. world’s largest GG I (D. Lin phot)


J. Ledford with Sao Tome tarantula.  GG I (D. Lin phot)

PARTNERS We gratefully acknowledge the support of the Research Investment Fund of the California Academy of Sciences, the Société de Conservation et Développement  (SCD) for logistics, ground transportation and lodging, STePUP of Sao Tome http://www.stepup.st/ and especially the generosity of three private individuals, George F. Breed, Gerry F. Ohrstrom and Timothy M. Muller, for making GG III possible.