Fernando de Noronha I: Tropical Forests of Yesteryear

On February 20^th, Darwin and a small party (including the captain) went ashore to survey the island of Fernando de Noronha.  It sounds like the landing was difficult (modern sources say the western shore is quite rocky and rough). Shortly after the survey party was picked up later that day, FitzRoy determined  that it was not worth staying any longer and the Beagle moved on.

Morro do Pico, the highest point of the island of Fernando de Noronha (photo from Wikipedia, drawing from Voyage of the Beagle):

In the short time he spent on the island, Darwin does get his first taste of a tropical forest, as all the other islands that he visited were more arid or completely devoid of vegetation.  In his diary he writes:

“I spent a most delightful day in wandering about the woods. — The whole island is one forest, & this is so thickly intertwined that it requires great exertion to crawl along. — The scenery was very beautiful, & large Magnolias & Laurels & trees covered with delicate flowers ought to have satisfied me…. All the trees either bearing some fruit or large flowers is perhaps one of the most striking things that meet one whilst wandering in a wood in these glorious regions ” (Feb 20)

Though he also realizes the best is yet to come:

“But I am sure all the grandeur of the Tropics has not yet been seen by me. — We had no gaudy birds, No humming birds. No large flowers ” (Feb 20)

Ironically, even though his description was short, Darwin provides history with a unique description of forests that no longer exist. The island was used as a penal colony for many years, and in order to prevent prisoners from building escape boats, the island was almost completely deforested later in the 19^th century.  Some trees grow there today, but the original forests that Darwin experienced are gone.

Google map of location of Fernando Noronha (note that you can zoom in for details):

Ecologically the islands are best known for their marine life – particularly sea turtles and dolphins (mmm…tasty to hungry sailors). There are a few endemic species located on the island itself, however there seems to be a number of problems with invasive species. One species in particular, the Tegu lizard, plays out a story seen on many other tropical islands. Tegu were introduced to control rats (another invasive species) in the 1950’s.  In a classic example of poor (or no) planning, Tegu are active in the day and rats at night.  So now they both prey on the local bird populations. One of the many paths to island extinctions…

Argentine black and white tegu, (Tupinambis merianae) – from Wikipedia:

One other biological note about the island: During my research I found that there is a concentration of amphibian deformities on the island.  40% of all the toads on the island are deformed (about 4x the number of deformed toads found on the mainland).  One explanation posed by the researchers – lack of predation. Normally the deformed frogs would be caught and eaten by predators – in other words (and her comes the connection to Darwin), natural selection would kick in and select against deformation in the population.  (See a 2009 abstract on this research.)

A little more about the islands: Fernando de Noronha was reported to have been discovered in 1503 by a Portuguese expedition led by Fernão de Loronha (though there is some question about whether or not other European explores visited the island a couple years earlier). The island became known as the “island of Fernão de Loronha”, which later “evolved” into Fernando de Noronha. The island changed ownership several times (at one or more time being controlled by the English, French, and Dutch), and eventually came under control of nearby Brazil. By the time Darwin arrived, prisoners were being exiled to the island, and later in the 19^th century the island became a formal “prison island” (which it remained until 1957). In 1988 much of the island (and surrounding islets) was declared a Maritime National Park, and in 2001 it was declared a UNESCO World Heritage Site. Today the Fernando de Noronha is primarily a tourist destination

I was going to discuss the geology of Fernando today, too, but seeing as the diary is pretty sparse the next few days, I’ll come back to the rocks tomorrow.  That’s sort of the same attitude Darwin had that day.  Uncharacteristically he wrote:

 “I have written one account of the Island in my geology and it is much too hard work to copy anything when the sun is only a few degrees from the Zenith.” (Feb 20)

Who can blame him – he was writing in a lot of different journals every day, and often copying the info into letters back home, too. (RJV)

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