TY - JOUR
T1 - Soil micro-organisms and competitive ability of a tussock grass species in a dry ecosystem
AU - Lozano, Yudi M.
AU - Hortal, Sara
AU - Armas, Cristina
AU - Pugnaire, Francisco I.
PY - 2019
Y1 - 2019
N2 - Drylands are among the most threatened ecosystems in the world because of the effects of global change and because they are not particularly resilient. Regeneration after disturbance is quite slow and secondary succession can be delayed to the point of nearly stop. This is exacerbated when the community is strongly dominated by a single species able to quickly respond after disturbance. One example of such monospecific dominance is the colonization of abandoned fields in SE Spain by an early successional and native tussock grass, Lygeum spartum, that seems to halt succession. Here we tested the competitive ability of Lygeum against Salsola oppositifolia, a shrub species that can be found interspersed with Lygeum in mid-successional stages, and assessed how plant–soil interactions mediate the outcome of plant–plant competition. To do so, we sowed seeds and grew plants of Lygeum and Salsola in either intra- or interspecific competition under controlled conditions using sterile field soils inoculated with either live (i.e., with micro-organisms) or sterile soil extracts from the understories of either Lygeum or Salsola. Soil nutrient content, seed germination rate, and shoot mass growth were determined after 5ÃÂ months, and soil bacterial communities were characterized by sequencing. Lygeum soil micro-organisms and soil properties, such as the high content of N and organic matter, enhanced seed germination rate of Lygeum individuals. By contrast, Salsola adults outperformed Lygeum when growing in interspecific competition. Synthesis. The enhanced competitive ability of Lygeum, which was mediated by soil micro-organisms, may lead to complete dominance of Lygeum in the plant community right after abandonment of agricultural fields. However, when the plant community is already developed, Lygeum would be unable to enforce such dominance. We conclude that positive plant–soil feedbacks combined with certain plant traits such as clonal growth support the strong resilience of Lygeum and allow for its dominance in extreme habitats.
AB - Drylands are among the most threatened ecosystems in the world because of the effects of global change and because they are not particularly resilient. Regeneration after disturbance is quite slow and secondary succession can be delayed to the point of nearly stop. This is exacerbated when the community is strongly dominated by a single species able to quickly respond after disturbance. One example of such monospecific dominance is the colonization of abandoned fields in SE Spain by an early successional and native tussock grass, Lygeum spartum, that seems to halt succession. Here we tested the competitive ability of Lygeum against Salsola oppositifolia, a shrub species that can be found interspersed with Lygeum in mid-successional stages, and assessed how plant–soil interactions mediate the outcome of plant–plant competition. To do so, we sowed seeds and grew plants of Lygeum and Salsola in either intra- or interspecific competition under controlled conditions using sterile field soils inoculated with either live (i.e., with micro-organisms) or sterile soil extracts from the understories of either Lygeum or Salsola. Soil nutrient content, seed germination rate, and shoot mass growth were determined after 5ÃÂ months, and soil bacterial communities were characterized by sequencing. Lygeum soil micro-organisms and soil properties, such as the high content of N and organic matter, enhanced seed germination rate of Lygeum individuals. By contrast, Salsola adults outperformed Lygeum when growing in interspecific competition. Synthesis. The enhanced competitive ability of Lygeum, which was mediated by soil micro-organisms, may lead to complete dominance of Lygeum in the plant community right after abandonment of agricultural fields. However, when the plant community is already developed, Lygeum would be unable to enforce such dominance. We conclude that positive plant–soil feedbacks combined with certain plant traits such as clonal growth support the strong resilience of Lygeum and allow for its dominance in extreme habitats.
KW - arid regions
KW - bacteria
KW - bunchgrasses
KW - soil microbiology
KW - soils
UR - http://handle.westernsydney.edu.au:8081/1959.7/uws:50823
U2 - 10.1111/1365-2745.13104
DO - 10.1111/1365-2745.13104
M3 - Article
SN - 0022-0477
VL - 107
SP - 1215
EP - 1225
JO - Journal of Ecology
JF - Journal of Ecology
IS - 3
ER -