Whenever we think of the tropics, we picture white sandy beaches and palm trees. We imagine beautiful coral reefs in ocean green waters under the clear blue sky. Other times, we imagine lush green forest with rich fauna. If there is one thing we all know for sure—the tropics are nature’s bounty.
The region between the latitudes of Tropic of Cancer and Tropic of Capricorn, and in and around the equator is often referred to as tropics. This region receives maximum sunlight and rain, and remain hot and humid throughout the year. Incidentally, this climate is conducive to a plethora of flora and fauna to flourish. According to the United Nations: “Tropics account for 40 percent of the world’s total surface area and are host to approximately 80 percent of the world’s biodiversity.”
Despite their rich biodiversity, the tropics are plagued with problems. The predominant challenge being urbanisation. The United Nations estimates that by 2050, over half of the world’s population will settle down in this region. It is with the intent of spreading awareness and conserving the tropics, International Day of the Tropics is observed on June 29 every year. On this occasion, Soulveda celebrates the ecological diversity of the tropics, enlists the threats they face, and suggests ways to conserve them.
It is common knowledge that tropical rainforests are rich in flora and fauna. These rainforests contribute to over 50 percent of the world’s biodiversity. For example, the largest tropical rainforest—the Amazon—is home to innumerable species of plants, insects, birds and animals. Examples include Harpy eagles, assassin bugs, Brazillian wandering spiders, tree boas, green anacondas, jaguars, sloths, the hyacinth macaws and crimson topaz.
This rich biodiversity makes rainforests vulnerable to destruction. As a result, rainforests are one of the most endangered habitats on earth. Writes retired geography professor Robert William McColl in his book Encyclopaedia of World Geography, Volume 1: “Some scientists believe that as much as 30 acres of rainforest are being destroyed every minute in the rainforests of the world.” With the loss of forest cover due to urbanisation, illegal logging, slash and burn farming etc., countless species of plants and animals have lost their habitat and are on the brink of extinction.
Tropical Savanna Grasslands are often located adjacent to the tropical rainforests. This terrain is characterised by fewer trees, scattered shrubberies and abundant tall grasses. For instance, the Serengeti Plains of Tanzania are well-known for herbivores that graze and carnivores that hunt. These grasslands are home to lions, cheetahs, buffaloes, zebras, elephants and giraffes.
The one threat which savannahs all over the world are facing is desertification. This not only threatens the lives of flora and fauna of the region, but also humans. People in this region engage in cattle rearing or farming. Due to overgrazing or over-cultivation, the fertile savannah land turns into infertile desert sands. Ecologist Mark Nelson, in his book Pushing Our Limits: Insights from Biosphere 2 writes: “Savannahs worldwide—in Africa, South America, the Middle East, India and Australia—face ecological threats causing human misery. Devastating droughts and famines ravage overpopulated, over-cleared and overgrazed savannah lands.”
We often imagine tropical deserts to be barren lands. But deserts too are unique natural ecosystems, that support specific flora and fauna. They are home to a vast array of plants and animals that have adapted to harsh habitats. For instance, the Sahara is home to several varieties of cacti, animals such as camels, cheetahs and gazelles, birds like roadrunners, hawks and eagles, a variety of reptiles like snakes and crocodiles, and rodents, arachnoids and insects.
Thanks to humans, even the deserts are not safe anymore. One reason is the over-exploitation of groundwater which depletes the water table in these areas. Secondly, nuclear, oil and mining wastes are often carelessly disposed in these lands. Thirdly, desert ecosystems are threatened by global warming. Albeit counter-intuitive, it has recently been found that even small changes in temperature and precipitation affect the flora and fauna of the desert ecosystem and endangers them.
Tropical seas are often teeming with coral reefs. This is because, the well-lit shallow seas of the tropical region are favourable for the growth of corals. An example is the Great Barrier Reef which is the largest ecosystem of coral reefs present in the coral sea. It is estimated that this 2,300-kilometre-long reef has over 9,000 species of marine life.
Like any other ecosystem, reefs too are threatened because of global warming. The seas upon absorbing excess carbondioxide in the atmosphere become acidic. Ocean acidification then causes coral bleaching. Writes ecologist Jonathan T Phinney in his book Coral Reefs and Climate Change: Science and Management, “Acidification of the oceans, changes in the current patterns, increased incidence of disease and physical changes at the coral margins all have implications for coral reef ecosystems and associated human communities.”
The tropical montane cloud forests are biodiversity hotspots. They are a treasure trove of endemic species of plants and animals. In these forests, the temperature changes rapidly with increasing altitude.