The Evil Quartet
A biologist called Jared Diamond coined the phrase ‘the evil quartet’ to describe the four main human-induced causes of extinction: habitat degradation and fragmentation, introduction of exotic species and over harvesting.
Habitat degradation and fragmentation include wetland destruction, river pollution, deforestation of woodlands and rainforest, and even just the isolation of pockets of forest as roads are built through them. These changes affect species in a number of ways. They are associated with reductions in population sizes and increased isolation of populations as well as, potentially, novel selective pressures.
The introduction of exotic species can result in a rapid increase in numbers of the invasive species, at the cost of native species which are either out-competed or introduced to novel diseases. Such has been the case for native red squirrels in the UK since grey squirrels were introduced from north America. Changes can frequently have knock-on effects throughout the local environment.
Over harvesting, such as of fish stocks like North Atlantic Cod, can rapidly reduce the population size and impose very strong directional selective pressures on a species. The result can be rapid and large shifts in the size and age at which the species matures and how quickly the individuals grow. Again, these changes can lead to wider effects across the ecosystem.
‘Evil Quartet’ Highlights Threats to Biodiversity in Armenia
YEREVAN–Vem Media Arts of Yerevan recently completed the 10th in a series of 11 films about environmental issues in the Republic of Armenia. Its latest film, “Evil Quartet,” is about the threats to biodiversity. The 22-minute documentary was produced by Manuk Hergnyan, written by Inga Zarafyan, and directed by Hayk Kbeyan.
The film provides a scientific overview of an ecosystem and highlights several endangered species in Armenia, the impact of human development on wildlife, and the role of hunting and poaching.
Zarafyan highlights the major threats to biodiversity identified by bio-geographer Jared Diamond of UCLA, namely, aggression of species and overgrazing, hunting and poaching, chains of extinction, and loss of habitat, noting that “the music of this quartet is getting louder and louder in Armenia.”
The film includes testimony from experts at the Botany Institute, Zoology Institute, Center for Prevention of Infectious Diseases, World Wildlife Fund (WWF), and Saint Louis Zoo, who address the risk of losing numerous endemic species of rare flora and fauna found only in Armenia, with many listed in the Red Book of endangered species. Since the Bezoar goat and moufflon (wild sheep) are declining in numbers, for example, the Near Eastern leopard is nearing extinction.
The film notes that the natural corridors of the leopard stretch over dozens of kilometers in southern Armenia and parts of Nakhichevan and Nagorno Karabagh, and that they are highly valued by hunters.
WWF wildlife expert Alexander Malkhasyan indicates that leopards are killed at a rate of one every two years, and that “if the situation does not change, we will lose the leopard forever.” He points out that WWF photographed one of the rare leopards in Armenia for the first time in 2005, and for the second time in 2007. “The situation of leopards in Armenia is not good, with only five to seven leopards remaining,” warns Malkhasyan.
“We have to realize the truth that while preserving the biodiversity of species we preserve ourselves as Homo sapiens [modern humans],” concludes the narrator of the documentary.