Browsing by Author "Kizza-Nkambwe, Sarah"

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    Plant communities as indicators of anthropogenic disturbance on a peri-urban tropical wetland of Lutembe Bay wetland system, Uganda
    (Sustainable Environment, 2024) Takuwa, Nuubu; Wozei, Eleanor; Kizza-Nkambwe, Sarah; Malinga, Geoffrey; Kilande, George; Kinobe, Joel
    Wetland degradation linked to peri-urban anthropogenic pressures is a major threat to wetland biodiversity. However, little is known of the response of biodiversity to this disturbance. Biotic indicator species are useful for assessing the health and ecological integrity of wetlands. This study evaluated patterns of plant species richness and composition, and determined species characterizing each of three differently disturbed wetland sites of Lutembe Bay Wetland, a peri-urban Ramsar Wetland of International Importance and an Important Bird Area in Uganda. The study revealed that total nitrogen decreased following wetland degradation, but total phosphorous was not affected; pH values were <5.5, while OM content was low in the lightly and heavily (2.5–4.4%) degraded sites. While plant species richness did not differ among the sites, total species richness was higher in heavily disturbed, compared to lightly disturbed and relatively intact sites. Community composition differed significantly among the three sites. Indicator plant species were then identified which could be employed as a rapid assessment tool to infer the level of degradation in the sustainable management of Afrotropical wetlands by practitioners. Results show that continued unsustainable use of wetlands results in changes in soil properties and plant species composition, highlighting the need to restore anthropogenically disturbed parts of wetlands and to prevent further degradation of less degraded areas.
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    Soil Physical and Chemical Properties under Shea Tree (Vitellaria paradoxa) at Different Stages of Growth
    (East African Nature and Science Organization, 2024-09-02) Ogwok, Gertrude; Kizza-Nkambwe, Sarah; Kasima, Junior Senyonga; Mpewo, Maxmillan; Alele, Peter O.
    Shea tree (Vitellaria paradoxa), is one of the dominant agro-forestry species in Otuke district of Northern Uganda. Due to its economic importance and, in line with the numerous threats the tree is faced with, there is an urgent need for measures to conserve this species, for example, through incorporating annual food crops in the Shea tree parkland. This, however, requires a better understanding of tree-soil-food crop interactions. A number of studies of this aspect either considered only the mature Shea tree gardens or did not provide a clear distinction between the physiological states of the Shea tree. This was the motivation for this study where we compare variation in soil properties under mature and young Shea tree gardens with sites not having trees in Okwang sub-county, Otuke district. Five soil samples (up to 15 cm deep for top soil and 15-30 cm for sub-soil) were obtained per treatment using a soil auger. Our results show that in the top soil, only percent sand varied among the treatments, while, in the sub-soil, only percentage nitrogen and average phosphorus varied among the treatments. We also found that percentage top soil organic matter and percentage of sub-soil sand had negative strong correlations with maize and soybean yields, while percentage sub-soil clay had a strong positive correlation with maize and soybean yield. We conclude that variations in soil physical and chemical properties under Mature and Young Shea gardens only occur for those properties that have a direct link to tree residues