Synergistic impacts of co-occurring invasive grasses cause persistent effects in the soil-plant system after selective removal
Data files
Jan 20, 2020 version files 308.62 KB
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Arthropod_community.xlsx
102.36 KB
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arthropods_2years.xlsx
86.71 KB
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cerrado_veg_2018.csv
6.31 KB
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cohensd_2019.xlsx
11.02 KB
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full_pbis.csv
20.73 KB
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plant_biomass.xlsx
43.43 KB
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plant_community_inv_rem.csv
38.06 KB
Abstract
1. Human influence on the environment is so extensive that virtually all ecosystems on the planet are now affected by biological invasions. And, often, ecosystems are invaded by multiple co-occurring non-native species. Hence, it is important to understand the impacts these invasions are producing on biodiversity and ecosystem processes.
2. Here, we present results of a two-year long field experiment where we tested the effects of co-occurring invasive C4 African grasses in a Cerrado area in central Brazil. We compared plant and arthropod communities, plant biomass, and soil nitrogen dynamics and soil chemical characteristics across five experimental treatments: Urochloa decumbens removal, Melinis minutiflora removal, both U. decumbens, and M. minutiflora removal, U. decumbens and M. minutiflora invaded plots, and uninvaded Cerrado. We hypothesized that selective removal of invasive grasses would have distinct effects on the native ecosystem structure and functioning. We expected that each invasive grass would produce a different type of impact on the native ecosystem and that their impacts would be synergistic when co-occurring.
3. Removal of M. minutiflora doubled native plant diversity and biomass when compared to invaded plots, whereas removal of U. decumbens did not alter these parameters. Cerrado plots had four times more plant species than plots cleared of invasives. Removal of invasive grasses did not affect the species richness or community composition of soil epigeal fauna. Cerrado soils had lower fertility, organic matter content, and pH than invaded soils. The effects were generally higher when both invasive grasses were removed, suggesting impacts were synergistic, but M. minutiflora had greater effects on plants and soils than U. decumbens. Both invasive species produced negative impacts, but a single species was the main driver. We also detected persistent effects of the invasive grass species on the ecosystem after two years of removal.
4. We conclude that invasive species of the same functional group have similar types of effects in native ecosystems, but the magnitude of impact was largely dependent on invasive species biomass and cover. Where multiple invasive species are present, research and management of invaded ecosystems should tackle the interacting effects of co-occurring invaders.
Methods
Field experiment data. Datailed information can be found in the asssociated paper.
Usage notes
B or Bd = Urochloa decumbens removal treatment
G or Mm = Melinis minutiflora removal treatment
BG = Urochloa decumbens + Melinis minutiflora removal treatment
Legend for datasets:
Ag = Andropogon guayanus
Hr = Hyparrhenia rufa
D = all other plants
Control = no removal treatment
Cerrado = non-invaded plots
t/ha = tons/hectare