Weed flora of University of Benin in terms of diversity and richness using two ecological models
Weeds are as important as man to himself and its environment. Weed flora in terms of diversity and richness of University of Benin, Ugbowo campus were determined from four habitable parts using two ecological models: Margalef species richness (d) and Shannon-Wiener diversity (H). Primary data were collected from an inventory obtained from tossing 20 quadrants of (1 X 1) m2 randomly. A total of 81 weed species distributed in sixty one genera were encountered from counts within the quadrats. Two life forms were recorded: herbaceous life form with 76 representatives (93.83 %) and five shrubby life forms (6.17 %). The total weed flora is distributed among two plant groups of 20 families. These included three families belonging to monocotyledonous group and 17 belonging to dicotyledonous group. The dominant weeds are commonly found in families of Compositeae, Amaranthaceae, Euphorbiaceae, Lamiaceae, Commelinaceae, Poaceae and Cyperaceae. Weed taxa of these families are usually annual and ephemeral in life cycle. The study revealed enormous diversity in weed flora in the sites assessed based on Margalef species richness (d) and Shannon-Wiener diversity (H). These ecological models suggest that site B is the richest and most diverse followed by sites D, A and C respectively. Sorensen index at 50 % significance suggest the sites are similar. Among the dominant weed flora encountered include: Synedrella nodiflora, Sporobolus pyramidalis, Setaria barbata, Peperomia pellucida, Oldenlandia corymbosa, Mariscus flabelliformis, Kyllinga erecta, Gomphrena celosioides, Euphorbia hyssopifolia, Eleusine indica, Desmodium ramossisimum, Cyperus rotundus, Commelina diffusa, Cleome rutidosperma, Axonopus compressusandAlternanthera sessilis. The results suggest that these weeds encountered are significantly associated with man. Thus, require further studies on their dispersal, crop-plant-need association and weed-tree plant-association.
Key words: Weed flora, Nigerian University, Margalef model (d), Shannon-Wiener index (H), Sorensen index, Edo State, Nigeria.