Ecological Succession: Udzungwa Forest/ Waterfall Ecological succession is the process of community change and development of an ecological structure over

As all ecological communities, the Udzungwa area was definitely at one point colonized though primary succession. Surrounded by trees currently, the forest is constantly using ecological succession as organisms and species continually grow and die. This process, of course, takes gradual time.

Before trees can move in, colonizers must take over the areas. Colonizers are species of plants that take over areas to develop. There are early colonizers, middle colonizers and late colonizers. Early colonizers tend to be small, tolerant, fast-growing, opportunistic species that are effective at spreading their seeds. Early colonizers are also known as Pioneer Species: the first species to colonize a habitat. Examples of these types of plants in the Udzungwa area are moss, or lichen. This is why, near the waterfall, untouched parts of rock tend to grow moss heavily. Although these types of species are considered to be a "bother" - weeds, without this stage ecological succession would be nonexistent.

After the Pioneer stage, these species are gradually replaced by plants known as Middle colonizers. These plants may need special soil, grow slower, less tolerant, and are larger. The sequences of communities that develop throughout are known as the Seral Stage. Examples of these plants (middle colonizers) that grow during this stage in the Udzungwa area are vascular plants, other bigger plants and shrubs. This series of vegetation will lead to what is known as Late Colonization. Late colonization is the most complex of the three, where the colonizers are even slower, larger, and tolerant to competition. Here, the soil tends to be fully developed and rich in humus. The decaying matter of these plants creates new niches within the community for decomposers. In the Udzungwa forest, these are the small and large trees that surround everything. This stage is the last of the succession process, leading into the final stage of "Climax Community".

Climax community is the ultimate phase, where a community can grow no more. It is quite a rare thing in today's world for an ecological structure to reach the point of its climax community, as there are currently so many human interferences. This stage normally has the highest species diversity. The Udzungwa forest and waterfall however had almost reached its climax community, as it is so away from technology that organisms and vegetation had the liberty to expand. The climax community in this case is a full-fledged forest and thus a stable community of plants and animals is accomplished.

Nisha Kanabar 3/3/05