Data from: Periphyton density is similar on native and non-native plant species

Non-native plants increasingly dominate the vegetation in aquatic
ecosystems and thrive in eutrophic conditions. In eutrophic conditions,
submerged plants risk being overgrown by epiphytic algae; however, if
non-native plants are less susceptible to periphyton than natives, this
would contribute to their dominance. Non-native plants may differ from
natives in their susceptibility to periphyton growth due to differences in
nutrient release, allelopathy and architecture. Yet, there is mixed
evidence for whether plants interact with periphyton growth through
nutrient release and allelopathy, or whether plants are neutral so that
only their architecture matters for periphyton growth. We hypothesised
that (1) non-native submerged vascular plants support lower periphyton
density than native species, (2) native and non-native species are not
neutral substrate for periphyton and interact with periphyton and (3)
periphyton density increases with the plant structural complexity of plant
species. We conducted an experiment in a controlled climate chamber where
we grew 11 aquatic plant species and an artificial plant analogue in
monocultures in buckets. These buckets were inoculated with periphyton
that was collected locally from plants and hard substrate. Of the 11
living species, seven are native to Europe and four are non-native. The
periphyton density on these plants was quantified after five weeks. We
found that the periphyton density did not differ between non-native and
native plants and was not related to plant complexity. Three living plant
species supported lower periphyton densities than the artificial plant,
one supported a higher periphyton density and the other plants supported
similar densities. However, there was a strong negative correlation
between plant growth and periphyton density. We conclude that the
periphyton density varies greatly among plant species, even when these
were grown under similar conditions, but there was no indication that the
interaction with periphyton differs between native and non-native plant
species. Hence, non-native plants do not seem to benefit from reduced
periphyton colonisation compared to native species. Instead, certain
native and non-native species tolerate eutrophic conditions well and as a
consequence, they seem to host less periphyton than less tolerant species.