Natural Sciences

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Browsing Natural Sciences by Subject "Abundance"

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    Abundance and Diversity of Native Forage Species in Pastoral Karamoja Sub-Region, Uganda
    (African study monographs, 2015) Egeru, Anthony; Wasonga, Oliver; MacOpiyo, Laban; Mburu, John; Majaliwa Mwanjalolo, G.J
    Low input pastoral production systems rely exclusively on natural forage resources in space and time. Information on the abundance and diversity of such pastures is vital in improving livestock production and managing the biodiversity of grazing landscapes. This study documented grass and browse forage species utilised in pastoral Karamoja, and determined their relative abundance by district, season and grazing land cover. Up to 65 grass and 110 browse species were utilised in Karamoja Sub-region. In-situ assessments revealed that Chloris, Hyparrhennia, Sporobolus, Pennisetum, Aristida, Cynodon, Eragrostis, Setaria, and Panicum grasses had higher relative abundance. Triumfetta annua, Indigofera erecta, Acacia drepanolobium, Grewia holstii, Acacia kirkii, Acacia mellifera, Acacia tortolis, Maerua pseudopetalosa, Acacia oerfota, and Ocimmum canum woody species were the most abundant. From the community assessment, Hyparrhennia, Chloris, Panicum, Bracharia, Eragrostis, and Setaria grasses and Acacia mellifera, Cadaba farinose, Acacia oerfota, Acacia drepanolobium, Caparis tormentosa, Maerua pseudopetalosa and Hisbiscus micrantha woody plants were identified as the most abundant among the grazing land cover. The grass and browse forage species varied by season, location, and land cover type. The study also found detailed local knowledge of grass and browse forage species in the community. This study has shown the existence of high diversity among grass and browse forage species with differentiated relative abundance across space and time. This, and the detailed communal cultural knowledge, form a basis for the improvement of livestock production as well as biodiversity conservation in Karamoja sub-region.
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    Abundance, movements and habitat use by African Grey Parrots (Psittacus erithacus) in Budongo and Mabira forest reserves, Uganda
    (Journal of African Ornithology, 2007) Amuno, John B.; Massa, Renato; Dranzoa, Christine
    Populations of African Grey Parrots are threatened by increased forest loss and the pet trade. Budongo forest reserve has, for over 60 years, been subjected to selective logging. Mabira forest reserve faces human pressures characterised by extractive disturbances, and agricultural activities with increased boundary settlements. We estimated parrot populations using the ‘forest limiting circumference’ method, and ‘encounter rate approach’ for general abundance and forest type associations, respectively. Counts were conducted on flyways in the morning and evening of one day, and observations on food tree location and preference were made by forest type and time of day. Total parrot populations were estimated at 714 in Budongo and 342 in Mabira. Mean numbers of flocks observed per flyway were 4.18 ± 4.33 and 4.70 ± 2.71 for Budongo and Mabira, respectively. Similarly, flock sizes varied from 2.59 ± 2.95 in Budongo to 2.87 ± 3.06 in Mabira forest. High encounter rates were recorded in disturbed/secondary forests during foraging activities and these coincided with areas of abundant fruiting trees. Movements into and out of main forests followed regular flyways and inter-forest movements increased with forest fragmentation. However, the presence of forest strips seemed to enhance the stability of flyways. While African Grey Parrots in Budongo may benefit from its large size, the Mabira population is likely to face a greater threat of further decline. More protected areas are needed to maintain viable populations, and future research should focus on breeding ecology, population monitoring and the impact of trade activities on this species.
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    Effect of gap size and age on climber abundance and diversity in Budongo Forest Reserve, Uganda
    (African Journal of Ecology, 2000) Babweteera, Fred; Plumptre, Andrew; Obua, Joseph
    A study of the e¡ects of gap size and age on climber abundance and diversity was carried out in Budongo Forest Reserve in Uganda. Data were collected from compartments N5, W21, B1 and B3. Stump records were used to locate and estimate the ages of 78 gaps. Sample plots 5 5m were set up in the gaps to assess climber abundance and diversity. Climbers were more abundant and diverse in gaps that were more than 400m2, 15 months old and had more than 25% canopy opening. Momordica foetida was the most abundant climber species occurring on stems, branches and crowns of seedlings and saplings. There- fore, in order to keep natural regeneration free from climber tangles and produce good quality timber, clim- ber control should be a major activity in tropical high forest management.
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    A Rapid Assessment of the Existence (or Survival) of Macro Fauna in Different Land Uses in Kween District of Mount Elgon
    (Research Square, 2021) Aggrey, Siya; Kato, Arthur Martin; Egeru, Anthony; Luswata, Kizza Charles
    We explored the effect of different land uses on soil macro fauna species richness, abundance and diversity in Mount Elgon areas of Kween District, Uganda. Results Species richness was higher on the subsurface of the different land uses than belowground. A total of 647 individuals of both subsurface and belowground macro fauna were identified from the different land uses. Macro fauna abundance significantly varied across the five different land uses (H=10.1, d.f.=4, p=0.04). The average diversity of the subsurface was higher (0.71) than that belowground (0.20). The highest diversity of macro fauna was found in the intercrop of maize-beans followed by natural vegetation. Maize monocrop had the least abundance and diversity of both surface crawling and belowground macro fauna. This could be due the diversity of food and living environments as mixed cropping introduces landscape heterogeneity that accommodates diverse organisms across different land use systems. This study recommends extended studies on taxonomy, ecology and management of soil macro fauna with detailed inventories on the functional groups across land use/cover types and evaluations of varied agricultural intensification regimes on abundance and diversity of soil above and below ground macro fauna.
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    Taxonomic diversity, distinctness, and abundance of tree and shrub species in Kasagala forest reserve in Uganda: implications for management and conservation policy decisions
    (Tropical Conservation Science, 2010) Gwali, Samson; Okullo, Paul; Hafashimana, David; Mujuni Byabashaija, Denis
    The successful management of natural resources requires access to adequate information on social, economic, ecological, and cultural changes in order to mitigate their impacts through conservation interventions. In most cases, such information is provided in the form of simple diversity indices, which may not predict the complex nature of species functioning in ecosystems. In this study, we used rank abundance, analysis of similarities (ANOSIM), similarity percentages (SIMPER), and taxonomic-diversity and distinctness indices to show the status of tree and shrub species in Kasagala forest reserve in central Uganda. Four 100 × 100 m plots were established in four vegetation strata of the strict nature reserve of the forest, and diameter at breast height (DBH) of trees and shrubs ≥ 5 cm measured. There was no significant difference in species abundance in the four vegetation strata (Kruskal Wallis H = 2.614, p = 0.453; ANOSIM: R = -0.334, p = 0.995). The taxonomic diversity and distinctness of the four vegetation types ranged between 2.414 and 2.786 while the taxonomic distinctness values ranged between 2.897 and 2.978. The taxonomic diversity of the forest is generally even, suggesting a homogeneous community. We suggest that the managers of the forest constitute a continuous monitoring program aimed at controlling the impact of anthropogenic factors, one of the main influences for such low taxonomic distinctness values observed for this forest.