Md. Arafat Rahman

Biodiversity is the variety of life forms at all levels of biological systems. Rapid environmental changes typically cause mass extinctions. Most of the species that ever lived on Earth, amounting to over five billion species, are estimated to be extinct. Estimates on the number of Earth current species range from 10 million to 14 million, of which about 1.2 million have been documented and over 86 percent have not yet been described. World Biodiversity Day is celebrated on May 22 every year to raise awareness about biodiversity around the world. Biodiversity is a measure of variation at the genetic, species, and ecosystem
level. Terrestrial biodiversity is usually greater near the equator, which is the result of the warm climate and high primary productivity. Biodiversity is not distributed evenly on Earth, and is richer in the tropics. These tropical forest ecosystems cover less than ten percent of earth surface, and contain about ninety percent of the world species.
Marine biodiversity is usually higher along coasts in the Western Pacific, where sea surface temperature  is highest, and in the mid-latitudinal band in all oceans. There are latitudinal gradients in species diversity. Biodiversity generally tends to cluster in hotspots, and has been increasing through time, but will be likely to slow in the future as a primary result of deforestation. It encompasses the evolutionary, ecological, and cultural processes that sustain
life.
Forest biological diversity is a broad term that refers to all life forms found within forested areas and the ecological roles they perform. As such, forest biological diversity encompasses not just trees, but the multitude of plants, animals and microorganisms that inhabit forest areas and their associated genetic diversity. Forest biological diversity can be considered at different levels, including ecosystem, landscape, species, population and genetic. Complex interactions can occur within and between these levels.
Terrestrial biodiversity is thought to be up to 25 times greater than ocean biodiversity. Forests harbor most of Earth terrestrial biodiversity. The conservation of the world's biodiversity is thus utterly dependent on the way in which we interact with and use the world forests. A new method used in 2011, put the total number of species on Earth at 8.7 million, of which 2.1 million were estimated to live in the ocean. However, this estimate seems to under-represent the diversity of microorganisms.
Forests provide habitats for 80 percent of amphibian species, 75 percent of bird species and 68 percent of mammal species. About 60 percent of all vascular plants are found in tropical forests.Mangroves provide breeding grounds and nurseries for numerous species of fish and shellfishand help trap sediments that might otherwise adversely affect sea grass beds and coral reefs,which are habitats for many more marine species.Forests of Africa, South America and Southeast Asia and lowland forests of Australia, coastal Brazil, the Caribbean islands, Central America and insular Southeast Asia have many species
with small geographical distributions. Areas with dense human populations and intense agricultural land use, such as Europe, parts of Bangladesh, China, India and North America, are less intact in terms of their biodiversity.

The growing demand and lack of drinkable water on the planet presents an additional challenge to the future of human health. Partly, the problem lies in the success of water suppliers to increase supplies and failure of groups promoting the preservation of water resources. While the
distribution of clean water increases, in some parts of the world it remains unequal. According to the World Health Organization, only 71% of the global population used a safely managed drinking-water service.
Some of the health issues influenced by biodiversity include dietary health and nutrition security, infectious disease, medical science and medicinal resources, social and psychological health.
Biodiversity is also known to have an important role in reducing disaster risk and in post-disaster relief and recovery efforts. According to the United Nations Environment Programme a pathogen
like a virus have more chances to meet resistance in a diverse population. Therefore, in a population genetically similar it expands more easily. For example, the COVID-19 pandemic had fewer chances to occur in a world with higher biodiversity.
Biodiversity provides critical support for drug discovery and the availability of medicinal resources. A significant proportion of drugs are derived, directly or indirectly, from biological sources: at least 50% of the pharmaceutical compounds on the US market are derived from plants, animals and microorganisms, while about 80% of the world population depends on medicines from nature for primary healthcare. Only a tiny fraction of wild species has been investigated for medical potential. Biodiversity has been critical to advances throughout the fieldof bionics.
In absolute terms, the planet has lost 58% of its biodiversity since 1970 according to a 2016 study by the World Wildlife Fund. The Living Planet Report 2014 claims that "the number of mammals, birds, reptiles, amphibians, and fish across the globe is, on average, about half the size it was 40 years ago". Of that number, 39% accounts for the terrestrial wildlife gone, 39% for the marine wildlife gone and 76% for the freshwater wildlife gone.
Global agreements such as the Convention on Biological Diversity, give "sovereign national
rights over biological resources The agreements commit countries to "conserve biodiversity;develop resources for sustainability and share the benefits resulting from their use.
Bangladesh is a signatory to a number of international conventions, agreements and protocols relating to forests and forest resources. Even if some of them are not approved, all activities that are detrimental to their aims and objectives must be refrained from being signed. We are natures,nature is ours. Biodiversity is an integral part of this beautiful nature and environment. It is our responsibility to protect this invaluable resource of nature. That responsibility is not only for
biodiversity, but also for the survival of human beings.

The writer is a columnist