Abstract
Short-term, i.e. 4-9 weeks aboveground net primary production (ANPP) temporal patterns during the first post-fire year in western Seren-geti National Park, and potential differences in the factors limiting ANPP between burnt and non burnt grasslands were examined and es-tablished. Fire stimulated growth at early post-fire stages, even during the dry season, July-October and led to larger increments in green phytomass compared to the non burnt grassland at the onset of short rains, Octo-ber-December. Further, ANPP in burnt plots correlated well with the ratio leaf/total standing phytomass suggesting that the accumulation of standing dead material can be a limiting factor to ANPP in burnt grass-lands. However, ANPP in burnt plots was unrelated to rainfall contrary to earlier arguments, but reached peak earlier and declined early in the rain season, perhaps due to the interactive effects of fire and grazing in the area. In non burnt plots, the temporal change in ANPP was more related to rainfall availability, at least until mid-growing season. Also, the phytomass structure differed between burnt and non burnt grasslands, and together with litter did not recover to non burnt levels within the first post-fire year. The study has demonstrated that the desire of the fire man-agement program in Serengeti National Park, which is to supply green forage to both migra-tory and resident populations during dry season is being fulfilled.
Highlights
Fire can alter fundamental biogeochemical processes and functions in ecosystems, affecting nutrient and carbon budgets and fluxes [1,2,3,4]
The effect on primary production is crucial since biomass and net primary production are essential to ecosystem performance and function [5], and primary production determines the energy available for other trophic levels [6,7]
Frequent fires are inherent in some ecosystems such as tropical savannas [8]
Summary
Fire can alter fundamental biogeochemical processes and functions in ecosystems, affecting nutrient and carbon budgets and fluxes [1,2,3,4]. Frequent fires are inherent in some ecosystems such as tropical savannas [8] In such systems the understanding of its effects, in interaction with other ecological determinants on primary production is critical to guiding management practices that can maintain ecosystem’s sustainability [9]. The variety in responses appears to depend on the biomes in question, the characteristics of the fire regime [10] and the spatial scales and temporal scopes at which the studies have been conducted [3,11,12] Important to these differences are the factors that limit primary production in each case and the time lags in the responses to the controlling biophysical processes [1]
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