WHAT IS BIODIVERSITY? Mike Bruton, MTE Studios
2010 was the United Nations ‘Year of Biodiversity’, and we are now in the UN ‘Decade of Biodiversity’ (2011-2020). Yet how many people really understand the concept of biodiversity?
WHAT IS BIODIVERSITY? Mike Bruton, MTE Studios
2010 was the United Nations ‘Year of Biodiversity’, and we are now in the UN ‘Decade of Biodiversity’ (2011-2020). Yet how many people really understand the concept of biodiversity?
I am concerned that the science education sector, and the media, may be guilty of dumbing down the important but complex concept of biodiversity, which is traditionally regarded simply as the number of different species.
In fact, to most people, animal diversity is the variety of large, adult vertebrates that we see in game parks, and familiar invertebrates.
It was recently, and rather triumphantly, announced that an international study has predicted that there are about 8.74 million species of plants and animals on Earth. These include 7.77 million species of animals (of which only about 953 000 have been scientifically described) and about 298 000 species of plants; the rest are fungi, single-celled animals and algae. But surely a species count is only the crudest measure of this important concept?
Biodiversity should include:
• The diversity of living as well as extinct species
• The diversity of different life-history forms
• Diversity above and below the species level, including families, orders and superorders, and subspecies and variants.
• The diversity of the relationships between animals, plants and animals, and animals and micro-organisms. These relationships include predator-prey relationships, parasitism, hyperparasitism, symbioses, commensalism, pollination, etc.
• The diversity of plant and animal behaviour
• The diversity of habitats, ecosystems and biomes, including soil and water
• The diversity of human relationships with, and uses of, plants and animals
• The diversity of domesticated and genetically modified plants and animals
• The diversity of humans.
Every animal with different life-history stages (e.g. egg/caterpillar/pupa/adult) is effectively more than one ecological species and should be counted several times. Biodiversity should also include the variation within species and especially the extent and nature of the interactions between species, even if this is difficult to measure and quantify.
Biodiversity isn’t a simple, hierarchical Darwinian tree but a complex interlinked web. It is a measure of both the taxonomy as well as the ecology of an organism. Perhaps our pattern–forming minds tend to underestimate the messy complexity, and subtlety, of Nature.
In fact, biodiversity should be everything that we lose when a species goes extinct, all its interconnectedness as well as the biological memory of the millennia of ‘research and development’ that took place over millions of years to make it a species in the first place. Defined in this way, we are still a very long way from describing the true extent of plant and animal diversity, and measuring our impact on it.
Some would argue that it would be impossible to quantify biodiversity as it is defined above, but it is the nature of science that we need to try to quantify and measure even the most complex phenomena and systems.
In the days of Carl Linnaeus, who first developed the binomial system for classifying plants and animals that we use today, scientists also predicted that it would be impossible to identify all the species of life on Earth.
Understanding the concept of biodiversity is essential if we are to comprehend the full impact of humankind on natural species and their ecological relationships. The International Union for the Conservation of Nature and Natural Resources recently estimated that about one third of the 61 900 animal species on their list are classified as ‘vulnerable’, ‘endangered’, ‘critically endangered’ or ‘recently extinct’, with some groups, such as the amphibians and reptiles, in particularly rapid decline.
They also estimated that at the present rates of decline, as many as 50% of the world’s plants and animals could go extinct within the next 100 years.
Taxa that have recently gone extinct include a subspecies of the western black rhinoceros, Diceros bicornis longipes, from western Africa. The northern white rhinoceros, Ceratotherium simum cottoni, and the Javan rhinoceros, Rhinoceros sondaicus are almost certainly extinct in the wild. The dugong, Dugong dugon, that languid, sea grass grazing cow of the sea, is expected to go extinct within the next 40 years.
Fortunately, there are also some good news stories – the southern white rhinoceros, Ceratotherium simum simum, is back from the brink of extinction with its numbers increasing from a few hundred at the end of the 19th century to over 20 000 today. Central Asia’s Przewalski’s horse, Equus ferus, has moved from ‘critically endangered’ to ‘endangered’.
Recent research on the economics of biodiversity has revealed that the economic consequences of today’s biodiversity loss can be valued at between $1.5 trillion and $3 trillion. Furthermore, environmental economists have estimated the value of the so-called ‘free services’ that natural plants and animals, and their interrelationships, offer to humans, should these services be lost. The pollination of crops is, for instance, valued at over $150 billion per year.
Of course, an exciting aspect of biodiversity research is that new species are constantly being discovered every year. The International Institute for Species Exploration at Arizona State University, and an international committee of taxonomists, selects the ‘Top Ten New Species’ each year. In 2011 this list included a glow-in-the-dark mushroom, a batfish as flat as a pancake, a Titanic-munching bacterium, a leech with enormous teeth, a two-metre long fruit-eating lizard, a jumping cockroach, an orb-web spider whose webs are wide enough to span a river, and a duiker first found in an African bush meat market!
Developing a formula that predicts the true complexity of Nature would be the biologist’s equivalent of the physicist’s ‘Theory of Everything’. That’s the role of the scientists, but it is our role, as science educators and the media, to provide a true picture of the complexity of plants and animals, and the consequences of their loss due to extinction.
Professor Mike Bruton is a biologist and science educator. He is currently the MTE Studios Director of the Bahrain Science Centre in Bahrain.
