Sand Rivers

Matilda’s horned viper

20 January 2012

Yesterday, I read a BBC ARTICLE about the discovery of a new species of snake, the golden-scaled Mathilda’s Horned Viper. The researchers who described the new species have not revealed where they found it in order to protect the snake from the illegal trade in wild animals. However, the article does say that the snake’s range is probably limited to just a few square kilometers.

With a little bit of knowledge about Tanzania, we can actually deduce quite a lot of information from what’s given. Tanzania’s biodiversity hotspots, the areas with the greatest number of species and greatest likelihood of new discoveries, follow the eastern-arc mountains. The eastern-arc mountains are a series of very old ranges stretching from the Taita hills in southern Kenya to the Udzungwa mountains in southern Tanzania.

The Uluguru, Udzungwa, and Usambara mountains in particular are well known for rich biodiversity and endemic species. The mountains are so old that there has been ample time for speciation. Another factor contributing to this is the island effect of mountain tops. Each mountain top has a climate and/or soil composition that is often distinct from the base and lower slopes of the mountain. Furthermore, because mountains in Tanzania tend to have lots of water, they are good places for human settlement. As populations around the mountain increase, so does deforestation until all that’s left is a small island of old-growth forest at the very top of the mountain. As a result, each mountain top is completely cut off from neighboring mountains, even though the environmental conditions are more similar from mountain top to mountain top than from mountain top to the base of the mountain. In each little pocket of forest, completely different species evolve. Even in the Amazon rain forest, the highest rates of biodiversity occur in the hills and mountains in the western reaches of the ecosystem where you find the same isolating effect. Most telling? These island habitats tend to be just a few or a few dozen square kilometers in size.

Unfortunately, these amazing montane ecosystems are typically overshadowed by the more glamorous savanna ecosystems, so it’s nice to see them get a chance to shine. I just wish these best-kept secrets didn’t have to stay so secret.

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