Dr Anjani Ganase surveys what the world is losing through human activities, and makes an appeal for living within our means in the natural world.
On May 22 we will observe the International Day for Biological Diversity. Biodiversity denotes the variety of living organisms that make up the natural world around us. The world as we know it is the culmination of evolution over billions of years, the result of the slowly ever-changing global environment. Organisms evolve and co-evolve with each other and the environment.
The biodiversity of ecosystems is the result of balance between competition for resources and external disturbance events that create opportunities for new life. The diversity of habitats and organisms not only sustain biodiversity, but is essential to our survival. Plant stocks don’t just supply the fruits and vegetables we eat today but provide the genetic stock for future supplies in a changing climate. The terrestrial and marine habitats provide the chemicals for the pharmaceutical industry and are our treasure troves against diseases. Even the ideal composition of air we breathe is the product of millions of years of ecological evolution.
[caption id="attachment_955469" align="alignnone" width="1024"] A sign at the entrance of the Main Ridge Forest Reserve. Photo by Jeff K Mayers[/caption]
Over the last 10,000 years, human civilisation and advancements have resulted in significant biodiversity loss because of population growth and land converted for agriculture and homes. The rate of extinction is about 100 - 1,000 times higher than the rate before the humans. Scientists are referring to this era as the Anthropocene Extinction: a large portion of biodiversity is disappearing because of human activities.
Forests
Agriculture accounts for 80 per cent of the deforestation and 70 per cent of our freshwater use. Since 1990, about 420 million hectares have been lost; this total area is larger than India. Deforestation results in losses among the tree species (over 60,000); up to 144,000 species of fungi, 70,000 vertebrates, which include 3,700 mammals, 7,500 species of birds, 5,000 amphibians that live in the forest. For invertebrates, the loss can be as high as high as 1.3 million – a species of invertebrate for every citizen of TT. We cannot count the invisibles, microbes living in the soil and surfaces which contribute to functions of decomposition, pollination, habitat restructuring and plant distribution. More than 50 per cent of the world’s forest lie in five countries, Russia owns a whopping 20 per cent of the world’s forest, Brazil 12 per cent, Canada 8.5, the US 7.6 and China 5.4. This means that the activities and policies of any of these countries will have serious consequences for global biodiversity. While 44 per cent of TT is forested, only 28 per cent is considered primary forest, highest in biodiversity and untouched by human activity.
Wetlands
The world has lost about 13,600 km2 of tidal wetlands – mangroves, marshes and tidal flats. However, restorations have given back
