Combined effects of shading and clipping on the invasive alien macrophyte Elodea nuttallii

TY - JOUR

T1 - Combined effects of shading and clipping on the invasive alien macrophyte Elodea nuttallii

AU - He, Liang

AU - Bakker, Elisabeth S.

AU - Alirangues Nunez, Marta M.

AU - Hilt, Sabine

N1 - 6733, AqE; Data archiving: data archived at and property of IGB Berlin

PY - 2019

Y1 - 2019

N2 - The response of macrophytes to herbivory and mowing in freshwater ecosystems is ambiguous. A recent study based on a plant growth model and a meta-analysis of field studies suggested that submerged macrophytes are more susceptible to plant removal by herbivory when additionally shaded by periphyton. Here, we test whether such synergistic effects of shading and herbivory or mowing can be experimentally confirmed. We used Elodea nuttallii, one of the alien invasive species of the highest concern in Europe. It is a preferred species by herbivorous water birds and is subject to mowing as a common management measure. We exposed E. nuttallii to four levels of clipping, with and without additional shading. Our results show a synergistic effect between shading and clipping for final shoot height of E. nuttallii and an additive effect for biomass, as enhanced branching compensated for shoot biomass losses by clipping in shaded treatments. Our results indicate that shading may help to maintain a lower canopy height of E. nuttallii when grazed by water birds or mown, but does not synergistically reduce total plant biomass. We conclude that the response of aquatic macrophytes to combined stress by shading and herbivory or mowing can differ among growth parameters and among species and is important to consider in aquatic plant management.

AB - The response of macrophytes to herbivory and mowing in freshwater ecosystems is ambiguous. A recent study based on a plant growth model and a meta-analysis of field studies suggested that submerged macrophytes are more susceptible to plant removal by herbivory when additionally shaded by periphyton. Here, we test whether such synergistic effects of shading and herbivory or mowing can be experimentally confirmed. We used Elodea nuttallii, one of the alien invasive species of the highest concern in Europe. It is a preferred species by herbivorous water birds and is subject to mowing as a common management measure. We exposed E. nuttallii to four levels of clipping, with and without additional shading. Our results show a synergistic effect between shading and clipping for final shoot height of E. nuttallii and an additive effect for biomass, as enhanced branching compensated for shoot biomass losses by clipping in shaded treatments. Our results indicate that shading may help to maintain a lower canopy height of E. nuttallii when grazed by water birds or mown, but does not synergistically reduce total plant biomass. We conclude that the response of aquatic macrophytes to combined stress by shading and herbivory or mowing can differ among growth parameters and among species and is important to consider in aquatic plant management.

KW - Aquatic plants

KW - Herbivory

KW - Lake management

KW - Macrophyte harvesting

KW - international

U2 - 10.1016/j.aquabot.2018.11.014

DO - 10.1016/j.aquabot.2018.11.014

M3 - Article

SN - 0304-3770

VL - 154

SP - 24

EP - 27

JO - Aquatic Botany

JF - Aquatic Botany

ER -