Show simple item record Ramberg, L. Lindholm, M. Hessen, D.O. Murray-Hudson, M. Bonyongo, C. Heinl, M. Masamba, W. Vanderpost, C. Wolski, P. 2011-06-09T09:01:17Z 2011-06-09T09:01:17Z 2010-07-19
dc.identifier.citation Ramberg, L. et al (2010) Aquatic ecosystem responses to fire and flood size in the Okavango Delta: observations from the seasonal floodplains, Wetlands Ecology and Management, Vol.18, No. 5, pp. 587-595 en_US
dc.identifier.other DOI: 10.1007/s11273-010-9195-x
dc.description.abstract The frequency of fires in the Okavango Delta seasonal floodplains peaked at an intermediate frequency of flooding. Floodplains are commonly burnt every 3–5 years. This study showed fundamental changes in ecosystem properties due to burning. A burnt seasonal floodplain in the aquatic phase had oxygen levels well above saturation, 100–200%, while the levels in the un-burnt control site were below saturation and, at night, could decline to 10–40% saturation. The total phosphorous and total nitrogen concentrations were similar on both floodplains but considerably enriched relative to inflowing water, due to nutrient release from the flooded soil-sediment and animal droppings. Zooplankton biomass was very high in both systems although the abundance of fish fry was ten times higher on the un-burnt floodplain. In a low flood year the un-burnt floodplain water had high nutrient levels, primary production, methane emission, and subsequent uptake of methane in biota, as well as a high zooplankton biomass. The very high flood the following year showed the opposite with much lower production at all levels owing primarily to greater dilution of nutrients. The abundance of fish, however, was much higher during the high flood year. Macrophytes and litter provide direct shelter for fish fry but also promote low oxygen levels when decaying. Large flooded areas result in high fish production by removing obstacles related to congestion. This interplay between hydroperiod and fire may be crucial for the maintenance of high biological productivity both in the aquatic and terrestrial phases in a very nutrient poor wetland landscape. Understanding these interactions is crucial for optimal management. en_US
dc.language.iso en en_US
dc.publisher Springer, en_US
dc.subject Seasonal floodplain en_US
dc.subject Macrophyte en_US
dc.subject Okavango Delta en_US
dc.subject Zooplankton biomass en_US
dc.subject Fish productivity en_US
dc.title Aquatic ecosystem responses to fire and flood size in the Okavango Delta: observations from the seasonal floodplains en_US
dc.type Published Article en_US en_US

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