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Browsing Research Articles by Subject "Abundance"

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    Associations between Lantana camara L. (Verbenaceae) and common native species in an African savanna
    (British Ecological Society, 2024-10-06) Ssali, Fredrick; Baluku, Robert; Drileyo, Gilbert; Muhumuza, Moses
    Lantana camara L. (Verbenaceae) is recognised as a problematic invasive alien plant species in many parts of the world. To eradicate or control this global invader, we need to understand the drivers of its spread and impacts and the potential for native recovery after the invader has been removed. Here, we tested for species associations between L. camara and native plant species and large herbivores in Queen Elizabeth National Park, Uganda. We inventoried 40,100-m2 nested plots spread over a 1 × 1-km grid cell in the park's savanna landscape, with 11 plots located in uninvaded areas. Most of the plots (30 of 40) had been affected by fire. Lantana camara covered 29 (73%) plots, 11 (38%) of which were in open grassland. Of the large herbivores that frequented areas free of L. camara, the Ugandan kob Adenota kob thomasi Sclater tended to avoid the areas invaded. The floristic composition of invaded areas differed significantly from that of noninvaded areas, with several palatable species rare or absent from L. camara-invaded areas. Practical implication: These observations indicate the presence of potential recovery constraints that will need to be overcome after L. camara has been removed. Sustained efforts will be needed to suppress the invader and subsequently enrich and bolster native recovery.
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    Situational Analysis of Abiotic and Biotic Factors Influencing Abundance of Tissue Culture and Non-Tissue Culture Bananas in Small Holder Farms in Western Uganda
    (African Scholarly Science Communications Trust, 2022-04) Murongo, M. F.; Ayuke, O. F.; Mwine, T. J.
    Bananas are, in Uganda primarily, grown for domestic consumption and regional trade. Production is constrained by several factors such as declining soil fertility, pests and disease, and erratic rainfall. Tissue culture banana were introduced partly to solve some of the challenges in banana production, though uptake of such technologies by smallholder farmers is still low. A survey on plant parasitic nematodes, banana weevils, and selected soil factors was done to analyse their effect on the abundance of tissue culture banana (TCB) and non-tissue culture banana (NTCB). Soil and banana root samples were collected from heterogeneous on-farm orchard conditions in smallholder farms. Composite banana root samples and composite soil samples were collected from banana orchards already established by farmers. A total of 1,280 genets from 20 orchards were obtained. Composite soil samples were analysed for pH, potassium, phosphorus, nitrogen, and organic matter. Endo-parasitic Helicotylenchus multinctus, Platylenchus goodeyi, Radopholous similis and Meloidogyne spp were isolated from the composite root samples. Banana weevils were captured using the disc-on-stamp and split-pseudo stem traps. Redundancy Analysis (RDA) and logistic regression were run to ascertain the relationship between variations in biotic [Nematodes and weevils] and abiotic [pH, K, Av.P, N, and OM] factors affecting the abundance of the banana type. Canonical eigenvalues showed that both biotic and abiotic variables significantly affected the abundance of TCB and NTCB banana types. Abundance of TCB was influenced by the banana weevil (P<0.05) than it was by nematodes in the same farmers’ fields. Infestation with nematodes for TCB and NTCB banana types was not different (P<0.05). The banana weevils were significantly (P<0.05) distributed within the districts. Relative abundances for the pH, phosphorus, potassium, nitrogen (%), organic matter (%) within districts were significant (P<0.05). Variations in soil pH and nitrogen availability resulted in significant interactions (P<0.05) that affected the abundance of the TCB types more than their contribution to the abundance of NTCB. The awareness that the interactions between nematodes, banana weevils, phosphorus, nitrogen, potassium and pH determine the abundance of banana types is important in shaping the adoption and production of the adopted banana technology. Mitigation of acidic pH, K, Av.P, N, and OM for soil fertility and reduction of the abundance of nematodes and weevils below the threshold will enhance banana production among small holder farmers in Uganda.