There is a place in the world where all the forces of nature converge and create an environment so unique that there are more animals than anywhere else on the planet. Volcanoes covered in tropical jungles rise above an ocean full of coral reefs and ecosystems intertwine to create unparalleled biodiversity. It is Insulindia, the malay archipelagothe land of 25,000 islands that, between 1854 and 1862, he explored Alfred Russel Wallace and where he made some of the most important scientific discoveries of his time.
Wallace traveled in a tireless desire to demonstrate how geography affects the distribution areas of species, conditions their origins and multiplies their diversity. Meanwhile, from his home in Downe, another naturalist, Charles Darwincompiled the infinite evidence and arguments that would support the publication in 1859 of The origin of species, the book that conceptually disrupted the world. Whenever he embarked on an expedition, Darwin He carried with him a copy of The lost paradise by John Milton.
It was in the Galapagos Islands that Darwin's nemesis occurred, the shift from a timorous religious mentality to an openly heterodox one in which biological inheritance replaced the hand of the divine watchmaker. Galapagos, a paradise lost in the middle of the Pacific that, in the eyes of the young naturalist, appeared as a laboratory of evolution. Although in his five-year journey the Beagle He stayed only five weeks in the Galapagos; approximately a quarter of Darwin's notes and field book are dedicated to this place. He had found one of the primeval paradises of evolution, and there he began to throw Milton's creationist cargo overboard. Keeping in mind the amazement that Wallace and Darwin felt in their respective island paradises, it is better to understand what the naturalists who have just described a new paradise of sealess islands must have experienced.
South East Africa Montane Archipelago (SEAMA), this is its name. The landscape of the new ecoregion It is dominated by 30 granite hills, some of which exceed 3,000 meters in altitude. Are inselberg or “island mountains”, isolated hills that dominate the plain, batholiths formed between 600 and 125 million years ago. Today, the largest evergreen montane tropical forests survive in the 30 hills (the Mount Mabu) and smaller (the Mount Lycus) from southern Africa. Further up the hill, above these primeval forests, biologically unique subalpine meadows thrive.
In Africa, mountains often house relict forests (last refuge of species), remains of a wide forest belt of the Tertiary. Before lifting and progressive increase in aridity From the eastern plateaus, the forest spread across most of the continent.
During the Early Oligocene, as the global climate cooled, Pan-African rainforests began to fragment. This caused a significant reduction in forests throughout the Miocene. Forest fragmentation produced the “islands in the sky” that host the unique biodiversity we see today. Much of the original forest in East Africa was confined to these isolated mountainous patches that persisted thanks to the orographic rains.
Immersed in these small, confined forests, limited by their low dispersal capacity, some species were trapped in highland refuges. Over there the trade winds, loaded with humiditymaintained a relatively stable climate.
The later climatic fluctuations, throughout the late Cenozoic, hindered gene flow, the migration of genes, between individuals of the same species that were in adjacent mountains. So each of these rock islands constituted an evolutionary center which favored allopatric speciation (caused by the presence of a geographic barrier). Thus, until establishing the unique habitats, rich in endemic species: reptiles, amphibians, mammals, crabs and butterflies that now characterize African montane systems.
The wealth of paradise
The 3,300 square kilometers over which this small ecoregion extends are home to 30 species of strictly endemic butterflies, which only exist in the Montane Archipelago; six species of freshwater crabs; 11 species of amphibians; 22 new species of reptiles, including a new tiny pygmy chameleon (Rhampholeon maspictus); four new species of mammals and 117 species of strictly endemic plants. This is a remarkably high number for such a limited geographic area, and will likely increase when sampling of some groups of people is incorporated. cryptogams (seedless vegetables) and invertebrates that require the analysis of groups of specialized taxonomists.
He endemic component As a whole, it is a consequence of the isolation of the hills, separated since the Tertiary from the rest of the Pan-African forests by the immense plains covered with savannas, a sea of grass whose seasonal aridity prevents the development of forest biomes.
But not all are good news. Despite being of global importance for biodiversity and the efforts of the governments of Malawi and Mozambique, the ecoregion is seriously threatened. Since scientists began their studies 20 years ago, the mountains, buckling under the pressure of slash-and-burn agriculture, hunting and demand for fuel and timber, have lost a fifth of their rainforest extent, almost half in some cases, one of the rates of highest deforestation in Africa. If the trend does not change, the new ecoregion, an Eden of biodiversity, can become, like Milton's, another lost paradise. Races condemned to millions of years of solitude do not have a second chance on Earth.
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