| Summary: | Waterfalls gives the impression of a lifeless zone because researchers have historically
focused on the hydrology, ecotourism and geological features. Effective management will
require an understanding of changes in species composition and distribution of
macro-biota. Monthly samples were taken in wet and dry seasons, over two year period in
three regions along the 6817.7 m length of the Agbokum waterfalls. Macro-biota exhibited
distinct pattern in respect of seasonal and spatial changes. Trachelomonas
volzii, the most abundant phytoplankton species reduced from 686 in the dry
season to 143 in the wet, and from 455 downstream to 91, midstream (waterfalls region).
Zooplankton species Calanus finmarchicus decreased from 511 during dry
season to 36 in the wet and from 334 downstream to 7, midstream. 71.7 percent of the total
macro-invertebrates were recorded from downstream reaches while only 6.3 percent were
contributed by midstream. Percentage cover of marginal vegetation by Bambusasp,
Symphonia and Elaeis guineesis displayed progressive increase
from upstream reaching a maximum of 38.5 mean percent cover in the relatively undisturbed
downstream. In contrast, Raphia vinifera, Havea
brasiliensis, Grewia sp. and Cocos nucifera
shrank in size from 34% to 8% at the midstream stretches of the river while only
nymphia- rich vegetation becomes more frequent in the middle reaches.
The disturbance regimes of the midstream reaches of Agbokum waterfalls combined with its
very low faunal and floral diversity has made the environment unstable therefore
susceptible to the invasion of disturbance tolerant biota.
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