The lethal and sublethal effects of the aquatic macrophyte Myriophyllum spicatum on Baltic littoral planktivores

Abstract

Macrophyte architecture can structure predator-prey interactions, but it is the chemicals within the plant that may actually be lethal. We conducted aquarium experiments to study the effects of common aquatic macrophytes (Myriophyllum spicatum, Myriophyllum sibiricum, and Chara tomentosa) and a predator (perch, Perca fluviatilis) on the survival, habitat choice, swimming, and feeding activities of Baltic littoral planktivores, mysids Neomysis integer and Praunus flexuosus, and three-spined stickleback (Gasterosteus aculeatus) larvae. Chemicals excreted by M. spicatum in a dense patch caused high mortality (73% to 89%) in both mysid species but not in sticklebacks, whereas M. sibiricum and C. tomentosa had no lethal effects. In lower stem densities stickleback larvae and N. integer avoided M. spicatum even in the presence of predator signals, and M. spicatum lowered the swimming and feeding activities of stickleback larvae. Only P. flexuosus did not avoid M. spicatum vegetation. Areas occupied by M. spicatum seem to be highly unsuitable habitats for littoral mysids and three-spined stickleback larvae. Because M. spicatum is a dominant macrophyte in the study area and eutrophication further increases its abundance, it may strongly influence the occurrence and distribution of mysids and fish larvae in the littoral ecosystems of the Baltic Sea.

Effects of invasive macrophytes on freshwater fish and macroinvertebrate communities: the role of invasive plant traits

“…In terms of fish, invasive macrophytes exhibiting a NW trait can have lethal and sublethal effects on certain fish through direct effects of toxicity and a potential reduction in food items due to effects on macroinvertebrates (Linden & Lehtiniemi, 2005;Erhard, 2005).…”

“…and E. nuttallii were both shown to have allelopathic effects on cyanobacteria and lepidopteron larvae resulting in a competitive advantage over native species, which are depredated by herbivores (Erhard, 2005). M. spicatum can be lethal or sublethal to fish larvae (i.e., Neomysis integer Leach and Praunus flexuosus Müller, and Gasterosteus aculeatus L.) and has the potential to change fish distributions and occurrence of affected species in invaded habitats (Linden & Lehtiniemi, 2005). Kovalenko & Dibble (unpublished data) hypothesize that M. spicatum also changes the epiphytic community by exuding allelopathic compounds, resulting in macroinvertebrates avoiding M. spicatum as feeding habitat, and therefore, insectivorous fish as well.…”

Distribution differences and active habitat choices of invertebrates between macrophytes of different morphological complexity

“…Several other factors of natural plants could influence the invertebrate distributions. The animals could be affected by plantsecreted bioactive chemicals that could attract (Brönmark 1985), repel, or kill the invertebrates (Dhillon et al 1982;Lindén and Lehtiniemi 2005) or affect the periphyton food resources for the animals (Hilt 2006). Bioactive chemicals affecting biota have been documented for M. spicatum (Körner and Nicklisch 2002) and C. baltica (in plant extracts; WiumAndersen et al 1982), but not for P. pectinatus (Körner and Nicklisch 2002).…”

Degradation of gallic acid and hydrolysable polyphenols is constitutively activated in the freshwater plant-associated bacterium Matsuebacter sp. FB25

“…Hydrolysable polyphenols cause a reduced growth of larvae of the aquatic moth Acentria ephemerella (Choi et al 2002), and inhibit the growth of bacteria isolated from the gut of larvae . Exudates of M. spicatum also interfere with zooplankton (Linden & Lehtiniemi 2005). Hydrolysable polyphenols are actively excreted by M. spicatum (Gross 2003), but the fate of individual polyphenols, e.g.…”