Drivers of Perceived Nuisance Growth by Aquatic Plants

Abstract

Mass developments of macrophytes occur frequently worldwide and are often considered a nuisance when interfering with human activities. It is crucial to understand the drivers of this perception if we are to develop effective management strategies for ecosystems with macrophyte mass developments. Using a comprehensive survey spanning five sites with different macrophyte species in four countries (Norway, France, Germany and South Africa), we quantified the perception of macrophyte growth as a nuisance among residents and visitors, and for different recreational activities (swimming, boating, angling, appreciation of biodiversity, appreciation of landscape and birdwatching). We then used a Bayesian network approach to integrate the perception of nuisance with the consequences of plant removal. From the 1234 responses collected from the five sites, a range of 73–93% of the respondents across the sites considered macrophyte growth a nuisance at each site. Residents perceived macrophytes up to 23% more problematic than visitors. Environmental mindedness of respondents did not influence the perception of nuisance. Perceived nuisance of macrophytes was relatively similar for different recreational activities that were possible in each case study site, although we found some site-specific variation. Finally, we illustrate how Bayesian networks can be used to choose the best management option by balancing people’s perception of macrophyte growth with the potential consequences of macrophyte removal.

Mass development of aquatic plants: Effects of contrasting management scenarios on a suite of ecosystem services

“…The five study sites were selected based on reported major aquatic plant nuisance problems (Table 1; Misteli et al., 2023; Thiemer et al., 2023). We included rivers and lakes that contrast in plant growth form and have different predominant types of use and geographic setting.…”

“…We included rivers and lakes that contrast in plant growth form and have different predominant types of use and geographic setting. One of the sites is a nature reserve (Lake Grand‐Lieu) with restricted access in the core area, whereas access is free in all other sites (Table 1; see also Thiemer et al., 2023). The difference in prevailing plant growth form (submerged, emergent and free‐floating, Table 1) among the different study sites, can have an impact on the final ecosystem services provided.…”

“…Respondents were approached face-to-face in the field or did actively fill out the online survey, so they were well-informed and consented in their participation. We refer to Thiemer et al (2023) for further information and a complete survey text as Supporting Information. For the current study, we used the questions where respondents were asked: (i) to…”

“…We used data from extensive questionnaires carried out for the MadMacs project (for detailed description of the questionnaires and their collection see Thiemer et al, 2023) at each site to estimate the values of cultural services (cf. Immerzeel et al, 2021Immerzeel et al, , 2022.…”

Periphyton in urban freshwater facilitates transformation of trace organic compounds: A case study on iodinated contrast media

“…Their disappearance during regime shifts in lakes and rivers as a result of anthropogenic nutrient loading, climate warming and/or pesticides (Scheffer et al, 1993;Hilt et al, 2011;Polst et al, 2022) may thus also affect TrOC concentrations. In turn, mass developments of macrophytes are often recognized as nuisance (Thiemer et al, 2023) and mechanically removed (Thiemer et al, 2021), but may be valuable for supporting TrOC transformation by periphyton. Macrophyte management in surface waters receiving wastewater containing TrOCs should thus consider their positive effects on periphyton growth and TrOC removal.…”