Abstract

Aquatic macrophytes with floating leaves are often key ecological species that affect entire aquatic ecosystems. Here we describe an investigation of the importance of insect herbivory for population growth and leaf senescence in the yellow water lily (Nuphar lutea). In order to gain a general picture of the importance of herbivory under different conditions, we experimentally manipulated herbivory in a large lily population in natural still water and observed the natural development of 32 smaller populations in flowing water. Herbivory drastically increased leaf senescence, reducing leaf density. In the still water, over one summer, leaf density increased by a factor of 1.23 in the presence of water lily leaf beetles and 1.61 when herbivory was eliminated. In flowing water, population growth was restricted mainly by leaf crowdedness, which limited large dense populations. Herbivory by water lily leaf beetles also had a limiting effect on yellow water lily, again mainly in large dense populations. Small populations supported a lower density of beetles. Previous studies have not addressed population-level responses of vascular plants with floating leaves. Our results suggest that herbivory can result in greater light penetration into the water and reduce "enemy-free space" for aquatic species that find such space in water lily stands. We suggest that the water lily leaf beetle should be considered an "ecological engineer.".

Keywords

Nuphar lutea; Galerucella nymphaeae; Pyrrhalta; Biological control; Herbivory

Published in

Hydrobiologia
2012, Volume: 691, number: 1, pages: 81-88
Publisher: SPRINGER

SLU Authors

• Stenberg, Johan A.

  • Department of Ecology, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Ecology


Publication identifier

DOI: https://doi.org/10.1007/s10750-012-1035-y

Permanent link to this page (URI)

https://res.slu.se/id/publ/39927