OKOMU OIL PALM PLANTATION

Ecological study of seasonal distribution of weeds in oil palm plantation at Agbarha-Otor, Ughelli North Local Government Area of Delta State, Nigeria, was carried out during therainyand dry seasons of 2020. Quadrats measuring 10 m2 were laid at random and informationontheweed species were gathered and used to generate diversity indices as well as other ecological statistics. During the dry season the taxa ranged from 27 - 50, individual abundance (376–2821), Dominance_D (0.1819 – 0.4248), Simpson index (0.5752 – 0.962), Shannon Wiener idex(1.469 – 3.468), Evenness index (0.132 - 0.7635), Brillouin (1.437 – 3.268), Menhinickindex(0.7073 – 2.116), Margalef index (3.569 – 6.914), Equitability (0.4301 – 0.9278), Fisher_alpha(4.705 – 8.632), Berger-Parker (0.07979 – 0.6424) and Chao-1 was (27.38 – 50.5). In termsofmost abundant species, density, relative density and importance index value in dry seasonindecreasing order were Poaceae > Selaginellaceae > Arecaceae > Melastomataceae>Bromeliaceae > Asteraceae. Diverse families in decreasing order were Poaceae > Asteraceae>Fabaceae = Rubiaceae = Malvaceae > Amaranthaceae = Connaraceae > Acanthaceae=Cyperaceae = Euphorbiaceae = Polypodiaceae = Tiliaceae = Gentianaceae with 7, 6, 5, 5, 5, 3, 3, 2, 2, 2, 2, 2 and 2 species respectively. While in the rainy season taxa ranged from32- 57, individuals (312 – 2178), Dominance, Simpson, Shannon Weiner, Evenness, Brillouin, Menhinick, Margalef and Equitability indices were (0.04491 – 0.4904; 0.5096 – 0.9551; 1.488–3.454; 0.10390 – 586; 1.426 – 3.284; 0.7037 – 2.887; 4.061 – 8.706) respectively. Equitability(0.4182 – 0.866), Fisher_alpha (5.373 – 17.31), Berger-Parker (0.1197 – 0.6944) and Chao-1were(32 – 62.08) respectively. In terms of most abundant species, density, relative densityandabstractimportance value index in rainy season, six weed families namely Poaceae, Asteraceae, Fabaceae, Malvaceae, Rubiaceae and Connaraceae were predominant. Similarly, the most diverse families in decreasing order were Poaceae > Asteraceae, = Fabaceae, > Rubiaceae, =Malvacee, > Connaraceae = Amaranthaceae, > Acanthaceae = Cyperaceae = Euphorbiaceae=Gentianaceae = Polypodiaceae = Tiliaceae with 7, 6, 6, 5, 5, 3, 3, 2, 2, 2, 2, 2 and 2speciesrespectively.The knowledge of weed flora will enable us to know the appropriate methodtoeliminate them from our agricultural farms to reduce competition with our valuable crops

The stomach of 76 tree frogs belonging to one family (Hyperolidae), two genera (Afrixalus and Hyperolius) from the Okomu Oil Palm Plantation were examined for their food and feeding behaviour. The species examined included Afrixalus dorsalis, Hyperolius concolor, H. fusciventris, H. fusciventris burtoni, and H. picturatus. More males were collected than females and they accounted for 95% of the specimens collected. The stomach contents examined showed 20 individuals with empty stomachs, 23 with prey items and 33 stomachs with already digested prey items. The diet of the 5 species consisted of insects belonging to the order Hymenoptera, Coleoptera, Diptera, Orthoptera and members of the Araneidae. Hymenoptera constituted 16 .92% of the total prey items ingested by the tree frogs, followed by Diptera (7.69%), Coleoptera (6.15%), Araneida (4.62%) and Orthoptera (1.54%). Unidentified prey items and digested preys accounted for 12.31% and 50.77% respectively. Hymenoptera was a common diet among the Hyperolius species accounting for 75% of the prey items recovered from H. concolor, while Dipterans constituted a major portion (42%) of the prey items ingested by Afrixalus dorsalis. Although there were variations in feeding rate among these species, it was not statistically significant (p>0.05). The diet of the tree frogs in the plantation were a reflection of the prey items available rather than selective feeding