EPOW - Ecology Picture of the Week

An Ecosystem About to Collapse

Tarangire National Park
Tanzania

Explanation:  What is going on in this scene of apparent destruction?

Welcome to Tarangire National Park in northern Tanzania, in the tropics of east Africa.  The park spans some 1,096 square miles (2,850 sq km), but the formal park boundaries here cover only about 14 percent of the entire Tarangire ecosystem that reaches to the border of Kenya to the north, the Rift Escarpment to the west, and the Maasai Steppe to the south.

Tarangire National Park has an amazing density of many large animal species native to the region, particularly elephants, zebras, buffaloes, wildebeest, and many antelope.  

Conditions within the park proper do not look healthy.  In fact, they appear to be on the verge of a major ecological collapse, for several reasons:

Development of highways and human habitations outside the park boundary are dissuading or preventing the historic migration circuits of elephants, zebras, and other species.  In the 1990s, some 55,000 zebra and wildebeest undertook this seasonal migration outside the park boundaries, but now they are becoming more restricted to the less nutritious grasslands within the park, which are becoming overgrazed.

Elephants, being more confined to within the park boundaries, are seeking alternate food sources, including trees, which they break and collapse in search of nutrition.  This week's photo shows such breakage and destruction by elephants.

Additionally, the region has been in a drought situation for over six years, adding to the poor growth of grass and veldt vegetation, exacerbating problems of overgrazing and soil depletion and disturbance.  

Local communities, however, are engaged in conservation easements to help restore wildlife migration corridors and to ensure the health of the ecosystem.  Time will tell if this race against ecosystem collapse has been won or lost.
  

Information:
     Gereta, E., G.E.O. Meing'ataki, S. Mduma, and E. Wolanski.  2004.  The role of wetlands in wildlife migration in the Tarangire ecosystem, Tanzania.  Wetlands Ecology and Management 12:285-299.