The incredible variety of life on Earth that lends our planet its rich and utterly unique biodiversity, is in peril. Species are becoming threatened at an alarming rate, and scientists have been warning for years now that we are actually living through a mass extinction event - the sixth in our planet's history.

The last one, that wiped out the dinosaurs, was caused by a meteor crashing into Mexico's Yucatan Peninsula, all of 66 million years ago. A catastrophe like no other. The one we're living through today, that could take upto 2 million years to play out if its proponents are correct, is unquestionably anthropological.

Over the past few decades sky high extinction rates have become an issue of global concern for its rapid reduction of biodiversity worldwide.

Bangladesh is no exception in this regard. Though the country has a vast variety of flora and fauna, it is unfortunate that in recent decades the biodiversity of the country is under pressure due to over population and over- exploitation of natural resources.

The IUCN Red List of Threatened Species has been assessing the conservation status of plants, as well as animal species on a global scale for the past 50 years. Since its conception in 1964, the Red List has evolved to become the world's most comprehensive information source on the extinction risk of species.

IUCN Bangladesh published the first Red List of Threatened Animals of Bangladesh in 2000. The list has been updated through a sub-project entitled 'Updating Species Red List of Bangladesh' under the 'Strengthening Regional Cooperation for Wildlife Protection (SRCWP)' Project of the Bangladesh Forest Department which is funded by The World Bank.

The project commenced in December 2013 and ended in June 2016. A total of 1619 species were assessed and updated from seven different animal groups - mammals, birds, reptiles, amphibians, freshwater fishes, and butterflies.

Meanwhile, Bangladesh has recently achieved unprecedented successes in the environmental sector. Prime Minister Sheikh Hasina was recognised as a 'Champion of the Earth' in 2015 by the United Nations, in recognition of her government's policies in this regard. Experts suggest the coordination and promotion of national efforts and effective policymaking for ensuring appropriate biodiversity management practices.

Though the country is exceptionally rich with a vast variety of flora and fauna, it is unfortunate that in recent decades the biodiversity of the country is under pressure due to over population and over- exploitation of natural resources.

At present, many species of Bangladesh have reached a dreadful genetic loss. Unfortunately, detailed information and consummate inventories of such species often do not exist. The government is acutely conscious of this, and has in fact been preparing to face the challenge for several years.

Bangladesh has made tremendous progress in terms of taking development initiatives towards conservation and sustainable use of the threatened species.

Bangladesh Forest Department in collaboration with IUCN Bangladesh and with financial assistance from The World Bank, initiated a project titled 'Strengthening Regional Cooperation for Wildlife Protection' under which the subproject 'Updating Species Red List of Bangladesh' has updated the threat status of wildlife in the country.

At present a total of 127 species of mammals belonging to 35 families under 9 orders are found in Bangladesh. Information on the population of different species of mammals is scanty. Most of the studies during the last four decades are focused on the status of mammals, depending on the presence or absence of certain taxa rather than estimating population. As a result, population trend enumeration is very difficult for most of the mammalian species in the country.

However, from several studies, population data on some of the very known species are available such as Bengal Tiger, Asian Elephant, Hoolock Gibbon, Rhesus Macaque, Capped Langur, Common Langur, Spotted Deer, and a few species of bats and some cetaceans.

Even a century back, Bangladesh was a country of rich wetlands and forests. However, unfortunately, most of the forests have been degraded and are being converted into crop fields as well as human settlements.

The country has 1.45 million hectares of forest land (9.8% of total area), including 1.21 million hectares (84%) natural forest and 0.24 million hectares (16%) plantations as of 2007).

The Bengal Tiger was once found in all forest areas and even in some village groves of the country. Village-grove-dwelling tigers completely disappeared when the last tiger was shot in Banglabandha, Panchagarh, in 1962.

The species is now confined only to the mangrove forest of the Sundarbans, known to support one of the largest populations of the Bengal Tiger.

An estimated number of tigers was noted between 50 to 100 in 1969. During the last four decades several researchers estimated tigers in the Sundarbans largely on extrapolation of track counts from sample areas.

As a result, the number of tigers in the Sundarbans varied from 350 to 600 in these counts. These numbers seem to be overestimated if we consider tiger prey abundance and density. Based on the camera trap survey, together with the track counts, and in the light of the prey densities, the tiger population was estimated around 200 in 2004.

Recent camera trap surveys showed that 106 tigers are found in the Sundarbans (Forest Department statistics, 2015).

The Spotted Deer is widely distributed in all habitats of the Sundarbans. The estimates of the Spotted Deer ranges between 52600 and 80000, and 83000.

The relative abundance of Spotted Deer varies from habitat to habitat, a gradual reduction from west to east (as per statistics of 2002) and deer density increases with the habitat ensuring fresh drinking water (as per 2002 statistics).

Apart from the Sundarbans, several islands in the Bay of Bengal also support large populations of Spotted Deer.

The Forest Department released four pairs of Spotted Deer in Nijhum Dweep National Park in 1978 which increased up to 14000 in 2006. This number decreased to less than 2000 in 2015 because of habitat loss, food crises and newborn preyed upon by the jackals and feral dogs (as per statistics of 2015).

Present status of Mammals

Thirty eight species (29.7%) are classified as threatened in the country, while 7.1% were recorded as Near Threatened.

Among the threatened species, 44.7% are Critically Endangered followed by 31.6% Endangered and 23.7% Vulnerable.

Despite constant threats to the survival of these species in the country, still 26.6% of the mammalian species are recorded as Least Concern. Unfortunately, very little data is available for a considerably large group of mammals and hence, 39 species are recorded as Data Deficient.

Mammalogist Syed Mahmudur Rahman of the Forest Department said that a total of 11 (eleven) mammals species have already been recorded as extinct regionally (in Bangladesh) while 17 others are critically endangered. On the other hand, 12 species of mammals are endangered while at present 9 species are identified as vulnerable which should be taken under monitoring if conservation measures are not taken.

Mahmudur Rahman said that it would not be possible to take conservation measures if detailed information is not available. He further informed that currently 9 species are 'near-threatened' while 34 species are identified as 'least-concern'.

"We could not evaluate the status of 7 out of 138 species of mammals," he said, adding over 2000 species of freshwater fish were assessed.

But the decline in mammal populations would obviously continue unless safe habitats can be ensured for them in pretty short order. The Forest Department mammalogist suggested increasing tree coverage (afforestation) as one way to do this. Apart from that, encroachment of humans on forest land should stop, and the existing forest cover should never be used for agriculture or industrial purposes.