1 Tahrcountry Musings: Migration Pattern of Wild Animals Altered Worldwide.

Tuesday, June 02, 2009

Migration Pattern of Wild Animals Altered Worldwide.

Migration of millions of Wildebeest across Serengeti Plains is familiar to anyone who watches Discovery or National Geographic channel. It is an amazing phenomenon that keeps us glued to the screen. People who have seen it first have been spell bound by the spectacle. This magnificent natural phenomenon is in danger of disappearing from the face of earth due to man’s avarice.

According to a new study by Dr Grant Harris from Center for Biodiversity and Conservation at the American Museum of Natural History and associates published in the journal Endangered Species Research, all of the world's large-scale terrestrial migrations have been severely reduced and a quarter of the migrating species are believed to no longer migrate.

D r Grant Harris says “Conservation science has done a poor job in understanding how migrations work, and as a result many migrations have gone extinct”

Migration occurs when animals search for higher quality habitat or more abundant food. Ecologically, there are two reasons attributed to food availability and subsequent migration. In temperate regions of the world, higher-quality food shifts as the seasons change, and animals respond by moving along well-established routes. In the case of savannah ecosystems, rain and fire allow higher-quality food to grow. To track this animals sometimes have to move across expansive landscapes.

Human activity has severely affected the landscape and this prevents large groups of ungulates from tracking their food. Fencing, farming, and water restrictions have contributed to the change. Over-harvesting of the animals themselves has played a role in reducing the number of migrants.

Harris and his co-authors gathered information on all 24 species of large (over 20 kilograms) ungulates known for their mass migrations. The study covered Arctic tundra (Caribou), Eurasian steppes and plateaus (Chiru and Saiga), North American plains (bison and elk), and African savannahs (zebra and wildebeests).

All the 24 species in the current study lost migration routes and were reduced in number of individuals. In North America, bison are still considered migratory, but their range is now restricted to two small sites in Yellowstone and Alberta. Similar changes are found on other continents where human activity has affected the ability of species to move to new patches of food.

For six species in particular the situation is alarming. The springbok (Antidorcas marsupialis), black wildebeest (Connochaetes gnou), the blesbok (Damaliscus dorcas), and quagga (Equus quagga) of southern Africa; the kulan (Equus hemionus) of central Asia; and scimitar horned oryx (Oryx dammah) of northern Africa either no longer migrate or are impossible to be considered as migratory animals.

We are paying a heavy price for “development’ without any forethought about impact on environment

Posted with inputs from American Museum of Natural History

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