Soil macrofauna abundance under dominant tree species increases along a soil degradation gradient uri icon

abstract

  • Soil macrofauna contribute to key soil functions underpinning soil-mediated ecosystem services. There islimited understanding about the role of trees as â??resource islandsâ?? for soil macrofauna in agriculturallandscapes and how this interaction is affected by soil degradation status. The study assessed the spatialinfluence of three dominant trees namely, Croton megalocarpus, Eucalyptus grandis and Zanthoxylumgilletii, on soil macrofauna abundance, along a soil degradation gradient resulting from continuouscultivation for 10, 16 and 62 years. It was hypothesised that spatial variation in soil macrofauna abundanceis affected by duration of cultivation, tree species and distance from the tree trunk. Soils cultivatedfor 10 years showed highest soil nutrient levels. Notably, soil C and N were higher below the canopy ofC. megalocarpus (64.6 g kg1 C; 6.7 g kg1 N), than E. grandis (58.7 g kg1 C; 5.9 g kg1 N) and Z. gilletii(54.5 g kg1 C; 5.6 g kg1 N) after 10 years of cultivation. Similar trends were also found after 16 and 62years of cultivation, although the mean values for the two elements were below 40.0 g kg1 and4.0 g kg1, respectively. Higher soil macrofauna abundance was found after 16 and 62 years of cultivation,though this was dependent on tree species and soil macrofauna group. Earthworm abundance washighest below the canopy of Z. gilletii averaging 389 individuals and 160 individuals m2, respectively,compared to 14 individuals m2 after 10 years of cultivation. Conversely, beetles showed higher numbersunder E. grandis and C. megalocarpus than under Z. gilletii. Highest numbers of termites and centipedeswere found under E. grandis after 16 years of cultivation. These findings support the importance of adiverse tree cover in agricultural landscapes to conserve soil macrofauna communities and the contributionof their activity to soil ecological functions

publication date

  • 2017
  • 2017