Browsing Okavango Research Institute (ORI) by Author "Bonyongo, M."
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Mubyana, T.; Krah, M.; Totolo, O.; Bonyongo, M. (Journal of Arid Environments. http://www.elsevier.com/wps/find/journaldescription.cws_home/622855/description#description, NaN, 2003)[more][less]
Abstract: The effect of flooding on soil total nitrogen, phosphorus and microbial population in different vegetation zones (floodplain, island and woodland) and profile depth (0?1, 0?5, 2?0, 3?0, 4?0 and 5?0m) of the Okavango Delta was studied from February to July 1999. Total nitrogen significantly differed with soil profile depth, moisture regime and months. In the woodlands, insignificant total nitrogen was detected at all depths except at 0?1m, where 0?03% and 1?17% were detected in February and March, respectively. In the island samples, only 0?05% was detected at 4m in February. Nitrogen in the floodplain samples was concentrated in the A1 horizon where 0?12%, 0?61% and 0?03% were detected in February, March, and May, respectively. Organic phosphorus significantly differed with vegetation zone but not with months and depth. Although organic phosphorus was low (0?02–0?52%) at all sites, it was liberally distributed throughout the profiles. On the island, actinomycetes were only detected up to 2m in February and up to 3m in July. Fungi concentrated in the top 0?5m (103–105). In both the floodplain and island samples, bacteria concentrated in the upper 3m. However, after May, populations decreased significantly. In the floodplain, significant actinomycetes populations were only detected in the upper 0?5m. Generally, organic phosphorus showed positive correlations with fungal populations. This study indicates that these soils are low in total nitrogen and phosphorus. URI: http://hdl.handle.net/10311/293 Files in this item: 1
Influence of seasonal flooding.pdf (3.953Mb) -
Bartlam-Brooks, H.; Bonyongo, M.; Harris, S. (Fauna & Flora International, April 7, 2010)[more][less]
Abstract: Terrestrial wildlife migrations, once common, are now rare because of ecosystem fragmentation and uncontrolled hunting. Botswana historically contained migratory populations of many species but habitat fragmentation, especially by fences, has decreased the number and size of many of these populations. During a study investigating herbivore movement patterns in north-west Botswana we recorded a long-distance zebra Equus burchelli antiquorum migration between the Okavango Delta and Makgadikgadi grasslands, a round-trip distance of 588 km; 55% of 11 animals collared in the south-eastern peripheral delta made this journey. This was unexpected as, between 1968 and 2004, the migration could not have followed its present course because of the bisection of the route by a veterinary cordon fence. As little evidence exists to suggest that large-scale movements by medium-sized herbivores can be restored, it is of significant interest that this migration was established to the present highly directed route within 4 years of the fence being removed. The success of wildlife corridors, currently being advocated as the best way to re-establish ecosystem connectivity, relies on animals utilizing novel areas by moving between the connected areas. Our findings suggest that medium-sized herbivores may be able to re-establish migrations relatively quickly once physical barriers have been removed and that the success of future system linkages could be increased by utilizing past migratory routes. URI: http://hdl.handle.net/10311/804 Files in this item: 1
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