Some Aspects of the Ecology of Senna occidentalis (L.) Link around Awka in Anambra State, Nigeria

This study investigated the ecological characteristics, abundance and distribution of Senna occidentalis (L.) and the associated species in the sampled sites around Awka in Anambra State, Nigeria. The aim of the study was to determine the ecological status of this important plant in order to proffer appropriate conservation measures to forestall its extermination in the study area (if need be). Abundance measures such as relative density, relative frequency, relative abundance, and importance value indexs were estimated for the plant and its associated species in the study sites. The Shannon-Weiner index of diversity was adopted to determine the species diversity of the sampled sites. The relative abundance values for S. occidentalis in the study sites (Iffite Awka and Agu-Awka) where it was found were 1.41 and 1.60, respectively, and the importance value indexs for the plant in the same sites where it existed were 15.42 and 17.05, respectively. Those values were lower than those of some of the associated plant species in those sites. The plant was neither sighted nor recorded in Okpuno and Amansea study sites. The results showed that S. occidentalis is neither abundant nor dominant in the study area. The Shannon-Weiner index of diversity of the four sampled sites was 3.131, 3.273, 2.392, and 2.857, respectively. The sites where the plant existed had more species richness than the sites where it was not found. The calculated equitability of distribution of the plant and the associated plant species in the sampled sites for sites Iffite, Agu-Awka, Okpuno and Amansea, were 0.86, 0.91, 0.81, and 0.88, respectively. This implies that the plant species were largely evenly distributed in all the sites. Since S. occidentalis was not abundant in the study area, there is an urgent need for conservation measures to be implemented for the plant.