Page:Niger Delta Ecosystems- the ERA Handbook, 1998.djvu/85

The Freshwater Ecozone #

Some trees of the FAM that show the root adaptations described above include:
 * Alstonia boonei, which has lateral primary roots above ground, carrying secondary breather roots;
 * Anthocleista nobilis, a pioneer species with peg roots;
 * Ceiba pendantra, the silk cotton-tree, which has high buttresses;
 * Mitragyna ciliat ( or M. stipulosa), which develops knee-roots like branches from the horizontal 'mother' root below the surface;
 * Piptadena africana, with flat wavy buttresses;
 * Symphonia gabonensis, an example of knee-roots;
 * Uapaca guineensis, which puts out aerial roots;
 * Nauclea pobeguinii;
 * Nauclea diderrichii;
 * Chlorophora excelsa, called Iroko and highly prized as joinery and building timber;
 * Cleistopholis patens, used for making canoes;
 * Garcinia spp. used for chewing sticks;
 * Lophira procera, Ironwood;
 * Terminalia superba (Afara); and
 * Pterocarpus santaniloides.

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Because of the uneven or broken canopy, the floodplain forest is home to many climbing plants that use existing trees for support in order to reach direct light. These include the lianas and other epiphytes. In fact the freshwater ecozone has one of the most diverse ranges of orchid species in the world.

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An interesting phenomenon of the Freshwater ecozone, especially evident in the Floodplain sub-ecozone, is the Earthworm Ridges. These can be nearly a metre high and appear to made by the usual activity of Earthworms that work up the soil in order to escape annual flooding (much more research is required). Thus they rise above the high flood mark, and are not only refuges for worms during the flood season, but also for other animals (including rodents and ants). They carry plants that are sometimes more typical of the Lowland tropical rainforest. Like the termite mounds of the savannah ecozones they carry a wide variety of life forms and make fascinating ecosystems in their own right. 83