A research study headed by Dr Andrew Hamilton from The University of Melbourne’s School of Land and Environment has produced some startling numbers. Dr. Hamilton was compelled to find accurate figures for the number of tropical arthropod species (spiders, insects, mites, crustaceans, and similar organisms) because previous estimates ranged all the way from 30 to 100 million. Dr. Hamilton and his research team applied probability modeling techniques to try to make more precise estimates of what is realistically possible in terms of the number of species. Their data showed a ninety percent chance the number of tropical arthropods is between 2 and 7 million. Their best estimate is the number is 3.7 million species.
Given their estimate for tropical arthropods, the number of total species on Earth is about 5.5 million. The researchers wanted to have a more accurate estimate so then they would also be able to determine the severity of species extinction that is currently taking place. “Obviously, if we are starting with less species, we may be worse off than we thought, and also be reducing the complexity of ecosystems even faster,” said Dr Hamilton. He also made the mind-jarring statement concerning the relative lack of scientific documentation of the majority of those species, “The findings also mean that in spite of 250 years of taxonomic research, around 70 percent of arthropods await description.”
What does potentially 3.7 million species equate to for us? If there are 50,000 vertebrate species (birds, mammals, amphibians and reptiles), then there are over 70 times more tropical arthropods species. For example, reportedly a single tree in Peru was found to have 43 different species of ants by a scientist. If the researchers are correct, though, there are far fewer species living on Earth than was previously believed. So in a sense it is bad news, but perhaps it also will have us humans not taking for granted the biodiversity around us so much. In other words, since there aren’t 100 million species, we had better protect the ones that are here. Dr. Hamilton is not done with his research though he said the estimates can be improved further, “This is just a starting point with lots more room for improvement, as more data comes in, we can feed more into the model and generate more accurate results.”
Image Credit: Paul Dornau