Summary
Nematodes were sampled from sites under and between tree canopies in Tsavo National Park, Kenya. We tested the hypothesis that more nematodes would be present in the generally moister soil, under the canopy, with a larger biomass of green grass prevailing for many months of the year. We found that microbivorous nematodes comprised the bulk of the populations, approximately 90% of the total. Bacterivores were more numerous (approximately 3×105 on average) versus fungivores (approximately 5×104 on average) per m2, to 10 cm depth. All four trophic groups (plant parasites and omnivore/predators in addition to the microbivore groups mentioned above) were significantly higher under acacia than baobab in a drier site, but not significantly different under the two tree species in a wetter site. Only bacterivores were significantly different with respect to distance from the tree, with higher numbers associated with the higher microbial biomasses under the tree canopies. These higher microbial biomasses were reflected in 2.5 times more potentially mineralizable N under the tree canopies at the drier site. We suggest that belowground detrital and microbivorous food webs in savannas may be similar to those in temperate grasslands. Further proof of this idea awaits more extensive research.
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References
Anderson RV, Coleman DC (1977) The use of glass microbeads to simulate the natural environment for ecological experiments with bacteriophagic nematodes. J Nematol 9:319–322
Belsky AJ, Amundson RG, Duxbury JM, Riha SJ, Ali AR, Mwonga SM (1989) The effects of trees on their physical chemical and biological environments in a semi-arid savanna in Kenya. J Appl Ecol 26:1005–1024
Bourlière F (1983) Tropical savannas. Elsevier, Amsterdam
Coe M, Cumming DM, Phillipson J (1976) Biomass and production of large African herbivores in relation to rainfall and primary production. Oecologia 22:341–354
Coleman DC, Reid CPP, Cole CV (1983) Biological strategies of nutrient cycling in soil systems. Adv Ecol Res 13:1–55
Hunt HW, Coleman DC, Ingham ER, Elliott ET, Moore JC, Rose SL, Reid CPP, Morley CR (1987) The detrital food web in a shortgrass prairie. Biol Fertil Soils 3:57–68
Ingham RE, Trofymow JA, Ingham ER, Coleman DC (1985) Interactions of bacteria, fungi, and their nematode grazers: Effects on nutrient cycling and plant growth. Ecol Monogr 55:119–140
Jensen CL, Belsky AJ (1989) Grassland homogeneity in Tsavo National Park (West), Kenya. Afr J Ecol 27:35–44
Kaiser P (1983) The role of soil micro-organisms in savanna ecosystems. In: Bourlière F (ed) Tropical savannas. Ecosystems of the world. Elsevier, Amsterdam, chap 25, pp 541–557
Lavelle P (1983) The soil fauna of tropical savannas: I. The community structure. In: Bourlière F (ed) Tropical savannas. Ecosystems of the world. Elsevier, Amsterdam, pp 477–484
Menaut JC (1983) The vagetation of African savannas. In: Bourlière F (ed) Tropical savannas. Ecosystems of the world. Elsevier, Amsterdam, chap 6, pp 109–149
Paul EA, Clark FE (1989) Soil microbiology and biochemistry. Academic Press, San Diego
Phillipson J (1973) The biological efficiency of protein production by grazing and other land-based systems. In: Jones JGW (ed) The biological efficiency of protein production. Cambridge University Press, Cambridge, pp 217–235
Sombroek WG, Braun HMH, van der Pauw BJA (1982) Exploratory soil map and agroclimatic zone map of Kenya 1980. Kenya Soil Survey, Nairobi
Steinberger Y, Orion D, Whitford WG (1988) Population dynamics of nematodes in the Negev desert soil. Pedobiologia 31:223–228
Whitford WG (1989) Abiotic controls on the functional structure of soil food webs. Biol Fertil Soils 8:1–6
Yeates GW (1987) How plants affect nematodes. Adv Ecol Res 17:61–113
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Coleman, D.C., Edwards, A.L., Belsky, A.J. et al. The distribution and abundance of soil nematodes in East African savannas. Biol Fert Soils 12, 67–72 (1991). https://doi.org/10.1007/BF00369390
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DOI: https://doi.org/10.1007/BF00369390