Nature and biodiversity globally is declining dangerously due to mounting anthropogenic pressures in terms of human greed and thrust for more energy, security, food and economic development. These activities have hampered the ecosystem functioning and created ecological imbalances to such an extent that biological life is in a struggling mode. Interestingly, May 22 will be celebrated as world biodiversity day worldwide under the auspices of the United Nations (UNO) to increase the understanding and awareness about the extinction threats and conservation of biological diversity on this planet. In fact loss of nature will have major implications for human societies and cultures.
For those of the readers who don’t know it yet, let me tell you that earth has already entered into a sixth mass extinction event after having witnessed five mass extinctions during the course of its age at 4.6 billion years. This extinction is also called as Holocene or anthropocene extinction, because it is man driven. Scientists assume we are in the middle of this extinction and it is estimated to wipe out maximum of life from biosphere. A recent report from the Intergovernmental Science- Policy Platform on Biodiversity and Ecosystem Services at Paris (4 May, 2019) finds that around one million animal and plant species are threatened with extinction, first of its kind in the human history and species extinction rates are accelerating at an unprecedented rates worldwide. It is pertinent to mention that 8 million is the total estimated number of animal and plant species on Earth (including 5.5 million insect species) as per the recent scientific estimation.
Actually extinction is a natural phenomenon, and it occurs at a natural background rate of about one to five species per year. We’re losing biological species at 1,000 to 10,000 times the background rate, with literally dozens going extinct every day. As per the current IUCN estimates on red list of threatened species, one in four species are at risk of extinction thanks to human pressures in terms of so called economic development and prosperity. The major driving forces behind it are human overpopulation and over consumption of natural resources. Further, habitat destruction, overhunting, toxic pollution, invasion by alien species and climate change all based on anthropogenic activities are also responsible for this progressive and forthcoming loss or extinction of life. These undergoing events have resulted in the significantly faster extinction rate of biological species and loss of biological diversity. A recent research has also shown that nearly half of the 177 mammalian species surveyed lost more than 80% of their distribution between 1900 and 2015.
The fifth mass extinction popularly remembered and studied as K-T (Cretaceous-Tertiary) extinction event happened 65 million years ago and wiped away around 75% of life including the massive dinosaurs. However, evolutionary it paved way for the emergence of larger mammals including human beings with their increased diversity all over the world. Pertinently, the first mass extinction called as Ordovician mass extinction happened about 440 million years ago during the Ordovician Period of the Paleozoic Era on the Geological time scale. Overall, scientific evidences have accumulated that climate change, microbial infections, volcanic eruptions and meteor strikes have been the possible causes behind the past extinction events.
One school of scientific thought has been stressing that parasites, pathogens and predators are also the cause behind the extinction of host species due to severe host mortalities and debility, however, obeying the natural ecosystem laws, the aim of a parasite or predator has never been to extinct its host populations or species. Under natural conditions, the extinction of species is caused by the events like population bottlenecks (elimination of unhealthy populations), populations which are ecologically constrained due to low genetic diversity or least biological fitness or minimal survival chances due to diminished potential to demonstrate struggle for existence, or survival of the fittest. Biologically, the mass extinction events shape the evolution of species because a few lucky ones are enough fit to survive these extinctions, propagate, flourish and dominate, and new ones evolve albeit under natural control.
The climate change is a crucial factor that drives the mass species destruction and extinction worldwide. There is enough of the evidence and research showing that climate change and plastic pollution is altering the biodiversity and it will have devastating effects on health, food security and economy. The North West temperate Himalayan region bordering the valley of Kashmir has been recognised as the high impact region of the possible effects of changing climatic trends. The Himalayan fauna and flora including the insects, mammals and migratory species of birds will be the worst sufferers of the consequences of climate change. Pertinently the impact of global warming on Himalayas has attracted the attention of scientists worldwide keeping in view the vast stretches of glaciers and its other ecological features which have direct and indirect bearing on the animal life and economy.
Last but not least, we are in a deep environmental crisis and issues challenging the very essence of life. From now onwards future will purely depend on what we do and plan for nature, but above all nature will take its own course of action-at least we have to believe that natural selection operates with all accuracy, perfection and reason. It is a key mechanism of evolution, which has happened, is happening, and will happen for the betterment and continuity of life. Let us only hope for timely actions, priority initiatives and concrete policies by man to secure life in every form.
The writer teaches Zoology at Islamia College of Science and Commerce, Srinagar.