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Ngarega, B. K.

Publications and source records attributed to Ngarega, B. K..

2 recordsLinked to original sources

Modelling the effects of bioclimatic characteristics and climate change on the potential distribution of a monospecific species Colophospermum mopane (Benth.) Leonard in southern Africa.

Global climate change is gradually changing species distribution and their patterns of diversity. Yet, factors that influence the local distribution and habitat preferences for southern African species remain largely unexplored. Here, we computed the suitable habitats in the southern African region for Colophospermum mopane (Benth.) using the maximum entropy (Maxent) modeling approach. We utilized one Global Circulation Model (GCM) and three Representative concentration pathways (RCPs) to determine the current and future distribution of C. mopane. The results showed that the distribution of C. mopane was mainly influenced by solar radiation, annual temperature range, and annual precipitation. According to the species response curves, this species preferred habitats with annual precipitation of 130-200 mm, an annual temperature range of 28{degrees} C, and elevations of about 500 m above sea level. The results highlight that the geographic range of C. mopane is likely to expand along the borders of Zambia and Zimbabwe in the future, particularly in the miombo plains. Conversely, suitable habitat areas reduce significantly in the eastern area of the southern African region, while the western areas expand. Overall, the appropriate habitat areas will likely decline in the 2050s under both RCPs and expand in the 2070s under the two scenarios. This knowledge is important for landscape planners and rangeland managers working to safeguard biodiversity from extinction. HighlightsO_LIHigh reliability of models in habitat suitability modelling for C. mopane C_LIO_LISolar radiation is the most significant variable for the current distribution of mopane. C_LIO_LIClimate change is and will reduce the habitat suitability of our target species. C_LI

ecology

Present and Future Ecological Niche Modeling of Rift Valley fever in East Africa in Response to Climate Change

Rift Valley fever (RVF) has been linked with recurrent outbreaks among humans and livestock in several parts of the globe. Predicting RVFs habitat suitability under different climate scenarios offers vital information for developing informed management schemes. The present study evaluated the probable impacts of climate change on the distribution of RVF disease in East Africa (E. A.), using the maximum entropy (MaxEnt) model and the disease outbreak cases. Considering the potential of the spread of the disease in the East Africa region, we utilized two representative concentration pathways (RCP 4.5 and RCP 8.5) climate scenarios in the 2050s and 2070s (average for 2041-2060, and 2061-2080), respectively. All models had satisfactory AUC values of more than 0.809, which are considered excellent. Jackknife tests revealed that Bio4 (temperature seasonality), land use, and population density were the main factors influencing RVF distribution in the region. From the risk maps generated, we infer that, without regulations, this disease might establish itself across more extensive areas in the region, including most of Rwanda and Burundi. The ongoing trade between East African countries and changing climates could intensify RVF spread into new geographic extents with suitable habitats for the important zoonosis. The predicted suitable areas for RVF in eastern Kenya, southern Tanzania, and Somalia overlaps to a large extent where cattle keeping and pastoralism are highly practiced, thereby signifying the urgency to manage and control the disease. This work validates RVF outbreak cases effectiveness to map the diseases distribution, thus contributing to enhanced ecological modeling and improved disease tracking and control efforts in East Africa.

ecology