Biological Invasions

, Volume 11, Issue 4, pp 813–823

Soil recovery after removal of the N2-fixing invasive Acacia longifolia: consequences for ecosystem restoration

  • Elizabete Marchante
  • Annelise Kjøller
  • Sten Struwe
  • Helena Freitas
Original Paper

DOI: 10.1007/s10530-008-9295-1

Cite this article as:
Marchante, E., Kjøller, A., Struwe, S. et al. Biol Invasions (2009) 11: 813. doi:10.1007/s10530-008-9295-1


Invasion by Acacia longifolia alters soil characteristics and processes. The present study was conducted to determine if the changes in soil C and N pools and processes induced by A. longifolia persist after its removal, at the São Jacinto Dunes Nature Reserve (Portugal). Some areas had been invaded for a long time (>20 years) and others more recently (<10 years). For each type of invasion, (i.e., long-invaded and recently invaded), three treatments were used: (1) A. longifolia left intact; (2) A. longifolia was removed; and (3) both A. longifolia and litter layer were removed. Soil samples were collected once a year for four and half years and analysed for chemical and microbial properties. In general, microbial parameters responded faster than C and N pools. In long-invaded areas, two and half years after removal of plants and litter, basal respiration and microbial biomass had already decreased >30%, β-glucosaminidase activity (N mineralization index) >60% and potential nitrification >95%. Removal of plants and litter resulted in a >35% decrease in C and N content after four and half years. In recently invaded areas, β-glucosaminidase activity and potential nitrification showed a marked decrease (>54% and >95%, respectively) after removal of both A. longifolia and litter. Our results suggest that after removal of an N2-fixing invasive tree that changes ecosystem-level processes, it takes several years before soil nutrients and processes return to pre-invasion levels, but this legacy slowly diminish, suggesting that the susceptibility of native areas to (re)invasion is a function of the time elapsed since removal. Removal of the N-rich litter layer facilitates ecosystem recovery.


Ecosystem processesMicrobial activity and biomassC and N-cyclingPotential nitrificationSoil ecologyβ-glucosaminidase activity



Areas long-invaded by A. longifolia (>20 years)


Areas long-invaded where A. longifolia was left intact


Areas long-invaded where only A. longifolia was removed


Areas long-invaded where both A. longifolia and the litter layer were removed


Areas recently invaded by A. longifolia (<10 years)


Areas recently invaded where A. longifolia was left intact


Areas recently invaded where only A. longifolia was removed


Areas recently invaded where both A. longifolia and the litter layer were removed

Copyright information

© Springer Science+Business Media B.V. 2008

Authors and Affiliations

  • Elizabete Marchante
    • 1
    • 2
  • Annelise Kjøller
    • 2
  • Sten Struwe
    • 2
  • Helena Freitas
    • 1
  1. 1.Centre for Functional Ecology, Department of BotanyUniversity of CoimbraCoimbraPortugal
  2. 2.Department of Microbiology, Institute of BiologyUniversity of CopenhagenCopenhagen KDenmark