Short- and longterm impacts of Acacia longifolia invasion on belowground processes of a Mediterranean coastal dune ecosystem

TY - JOUR

T1 - Short- and longterm impacts of Acacia longifolia invasion on belowground processes of a Mediterranean coastal dune ecosystem

AU - Marchante, Elizabete

AU - Kjøller, Annelise

AU - Struwe, Sten

AU - Freitas, Helena

N1 - Keywords: BETA-GLUCOSAMINIDASE ACTIVITY; MICROBIAL BIOMASS; ENZYME-ACTIVITIES; PLANT INVASION; FOREST SOIL; NITROGEN; NUTRIENT; COMMUNITY; FYNBOS; FIRE

PY - 2008

Y1 - 2008

N2 - Many coastal dune ecosystems in Portugal are invaded by the leguminous tree Acacia longifolia (Andrews) Willd. This exotic species was first introduced over one hundred years ago in an effort to mitigate dune erosion and loss of coastal landscapes. However, since then A. longifolia has spread to new areas, displacing the native vegetation. These invaded ecosystems contrast with the native dune ecosystems that are typically dominated by herb and shrub communities. This study characterizes belowground changes to the native environment as a result of recent (<10 y) and long-term invasion (>20 y) by A. longifolia by analyzing a range of chemical and microbial parameters. Both invaded areas accumulated higher litter densities with greater N contents and lower C/N ratios than the native areas, which corresponded to lower C/N ratio and to higher potential rates of nitrification in the invaded soils. Long-term occupation by A. longifolia has significantly altered the soil properties with increased levels of organic C, total N and exchangeable cations resulting in higher microbial biomass, basal respiration, and p-glucosaminidase activity. However, basal respiration and microbial biomass were significantly higher within recent invasion sites when calculated relative to soil organic C. The results from this study show that invasions by A. longifolia have altered the original native ecosystem processes and that the impacts are more pronounced within long-term invaded sites. A positive feedback mechanism is apparent for A. longifolia invading these Mediterranean dunes, which can make the restoration of native plant communities increasingly difficult with time elapsed since invasion. (C) 2008 Elsevier B.V. All rights reserved.

AB - Many coastal dune ecosystems in Portugal are invaded by the leguminous tree Acacia longifolia (Andrews) Willd. This exotic species was first introduced over one hundred years ago in an effort to mitigate dune erosion and loss of coastal landscapes. However, since then A. longifolia has spread to new areas, displacing the native vegetation. These invaded ecosystems contrast with the native dune ecosystems that are typically dominated by herb and shrub communities. This study characterizes belowground changes to the native environment as a result of recent (<10 y) and long-term invasion (>20 y) by A. longifolia by analyzing a range of chemical and microbial parameters. Both invaded areas accumulated higher litter densities with greater N contents and lower C/N ratios than the native areas, which corresponded to lower C/N ratio and to higher potential rates of nitrification in the invaded soils. Long-term occupation by A. longifolia has significantly altered the soil properties with increased levels of organic C, total N and exchangeable cations resulting in higher microbial biomass, basal respiration, and p-glucosaminidase activity. However, basal respiration and microbial biomass were significantly higher within recent invasion sites when calculated relative to soil organic C. The results from this study show that invasions by A. longifolia have altered the original native ecosystem processes and that the impacts are more pronounced within long-term invaded sites. A positive feedback mechanism is apparent for A. longifolia invading these Mediterranean dunes, which can make the restoration of native plant communities increasingly difficult with time elapsed since invasion. (C) 2008 Elsevier B.V. All rights reserved.

KW - Faculty of Science

KW - Invasive arter

KW - Mikrobiel aktivitet

KW - Invasive plant species

KW - Microbial biomass

KW - Soil enzymes

U2 - 10.1016/j.apsoil.2008.04.004

DO - 10.1016/j.apsoil.2008.04.004

M3 - Journal article

SN - 0929-1393

VL - 40

SP - 210

EP - 217

JO - Applied Soil Ecology

JF - Applied Soil Ecology

IS - 2

ER -