Nature Conservation Against All ? Aquatic Macrophyte De-Weeding – Cut or Conserve ? A Stakeholder Analysis

De-weeding of streams and lakes occurs in Germany on a widespread level, mostly to ensure water runoff and to provide flood protection. But de-weeding also affects a range of stakeholders, who have their own reasons to support or oppose it. For the list of stakeholders identified, see chapter 4. As part of a project analysing the feasibility of using water plant biomass as a substrate for biogas production, we conducted a multi-method stakeholder analysis to evaluate stakeholders’ opinions about de-weeding. The results show a preference of all stakeholders, except those identifying with nature conservation, for aquatic de-weeding. Our findings also point to a lack of communication between stakeholders, resulting in biased opinions of the stakeholders against other stakeholders and starting points for conflict.


Motivation
The motivation for this study derives from the project "AquaMak -Aquatic Macrophytes: Economic and Ecological Ways of Use" which was carried out to evaluate the possible use of aquatic biomass from German rivers and lakes as a substrate in biogas production.A nationwide survey showed that a large amount of aquatic biomass was potentially available in Germany; furthermore, proven deweeding technologies make it feasible to farm this biomass for biogas production.But conflicts with stakeholders can hinder de-weeding initiatives.Handling these conflicts productively requires understanding the concerns and objectives of all the stakeholders engaged in the debate.

Goals of the study
The goal of this study is to present an overview of exemplary stakeholder concerns related to aquatic de-weeding.It was carried out as part of a feasibility study for using aquatic biomass in Germany as biogas substrate.The goal was to evaluate stakeholders' concerns about using existing biomass harvested during regular water maintenance activities.
The research questions are: 1. Which stakeholders are affected by aquatic deweeding?
2. What functions do they attribute to their nearby river or lake?
3. What is their opinion on de-weeding? 4. Who or what agency do they think is responsible for de-weeding? 5. Do they know other stakeholders being affected and their concerns?

Background
A quatic macrophytes, sometimes referred to as water weeds, form an essential part of aquatic ecosystems and serve many roles in them (Jeppesen et al. 2012).Aquatic macrophytes provide living and breeding space for aquatic fauna (Meyer & Hinrichs 2000;Mieczan 2007) and serve as food for various animals (Meyer 2000;Perrow et al. 1997;Baattrup-Pedersen et al. 2002).Often a population of aquatic macrophytes is seen as an indicator of clean waters (Thiébaut 2008) and helps to control microalgae population (Jasser 1995;Nakai et al. 1996;Nakai et al. 1999).There are even studies demonstrating how aquatic macrophytes can serve water purification goals by extracting heavy metals and other toxic substances from the water (Abdelmalik et al. 1973;Bolsunovsky & Bondareva 2008;Crum et al. 1999;Cecal et al. 2002).
The amount of aquatic macrophytes tolerated in rivers and lakes strongly depends on the intended use by the stakeholders.While nature conservation sees aquatic macrophytes as part of a self-regulating ecosystem that normally does not need intervention, this view is not shared by other stakeholders.Economic or recreational use of waterbodies often implies a "clean" river or lake, with aquatic macrophytes being a nuisance or even a threat to the intended use.Hence a possible amount of conflict potential between these and other stakeholder groups can be assumed.
Under normal circumstances, aquatic macrophyte populations are self-regulating and have even been known to collapse from time to time without strong intervention (Simberloff & Gibbons 2004).When populations grow too dense, this can lead to problems, for example depleted oxygen levels (Pieczyfiska & Tarmanowska 1996).Excessive growth negatively affects many stakeholders involved in the use of rivers and (artificial) lakes, including those in water-borne transportation, electrical power generation and potable water production (Raynes 1964).

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There are various ways of controlling excessive aquatic macrophyte growth, all of which have drawbacks.For example, the use of chemical substances in aquatic weed control (Eicher 1947) is prohibited in Germany due to ecological side effects, while more ecologically friendly methods (Caffrey et al. 2010) are restricted to local application.Methods applying herbivore antagonists of aquatic macrophytes (Cross 1969) often exchange effective control of aquatic macrophytes for the problem of neozoa proliferation (Hessen et al. 2004;Lake et al. 2002;Søndergaard et al. 1990).Nonetheless, a healthy balance of endemic herbivores like snails (Barrat-Segretain & Lemoine 2007) in water bodies does help to control aquatic macrophyte growth (Lombardo 2005). Zehnsdorf et.al. (2015) show that many water plants, including Elodea spp.can partly be controlled by shading, even if it grows under relatively low light conditions.The same holds true for extremely high radiation exposure, which also inhibits growth of different water plant species that are not acclimated to these conditions (Hussner et. al. 2010).For a comprehensive review of aquatic neophyte management methods, see Hussner et.al. (2017).
However, these measures are often insufficient to ensure the desired results, so physical extraction is needed to remove unwanted aquatic macrophytes.In German waterways, that is typically done using weed-cutting machinery, but this practice has generated its own controversy.First, some neophytic aquatic macrophytes such as Elodea spp.appear to outcompete other aquatic macrophytes after mechanical clearing of water bodies (Howard-Williams et al. 1996;Abernethy et al. 1996).Second, many aquatic macrophytes proliferate by cut-off fragments (Barrat-Segretain & Bornette 2000;Mielecki & Pieczynska 2005), making it critical that the method of mechanical cutting not itself be counterproductive.
New stakeholders in the de-weeding debate have emerged as multiple researchers have explored innovative uses for aquatic biomass.Its possible use as cattle fodder has been evaluated (Jorga et al. 1979), and aquatic macrophytes have been tested and seen as fit to serve as biomass for biogas production (Alvarez & Lidén 2008;Global Bioenergy Partnership, IEA Bioenergy 2016;Kuroda et al. 2014).Analyses of the biomass potential of aquatic macrophytes have been carried out in countries around the world, including Argentina (Fitzsimons et al. 1982), Japan (Kuroda et al. 2013) and India (Mathew et al. 2014;Sudhakar et al. 2013).
As Germany's potential of aquatic biomass remains largely untapped, new pressures have developed in the de-weeding debate.Still, despite studies into the motivations for and against de-weeding measures, we find no research into stakeholders' perceptions of these measures.Yet these perceptions play an everlarger role in societal decision-making, especially when centered on environmental concerns.In such matters,it is all too possible for misunderstandings to derail rational discussion.We have thus undertaken to characterize the diverse and sometimes conflicting stakeholder interests and concerns in the deweeding debate, so that that debate may proceed with as many informed participants as possible.
3 Methods W e used three instruments to gather data from various stakeholders about their opinions on aquatic de-weeding.Our primary instrument was a nationwide e-mail questionnaire survey (see supplementary material for the questionnaire).Secondarily, results were enriched through content analysis of press articles.And third, selected cases were investigated by a series of qualitative interviews with stakeholders.A stakeholder is, in our case, every person or institution which is using a river or lake or is being affected by its use or alteration.

Questionnaire
The questionnaire was sent out to all institutions in Germany identified as having tasks in water maintenance.This included public authorities in all Federal States as well as private tenants of lakes.
Service providers offering water maintenance services, identified by an Internet search and through the responses from water maintenance authorities, also received the questionnaire.We sent out a total of 1,123 questionnaires, of which 408 were returned, giving a response rate of 36,3%.
The questionnaire was part of the research project "AquaMak" and included, besides questions of interest here, several questions not related to this study.The data for this study was gained from a freetext form where informants could respond to the following questions: -Which stakeholders have voiced their concerns about de-weeding?-Were they supporting or opposing de-weeding?-What were their arguments?
The responses were collected and the arguments extracted, using Mayring's method of qualitative content analysis (Mayring 2015), see fig. 2.

Press article review
We identified press articles (newspapers, online publications) as an important source of insight into stakeholder perspectives on de-weeding, searching for the following terms: -De-weeding / Entkrautung /Verkrautung -River / Lake maintenance / Gewässerunterhaltung -Mähboot -Aquatic weeds -Nuisance aquatic macrophytes These articles often quote stakeholder's opinions, giving direct insight into concerns about aquatic macrophytes.Many incidents are published in newspapers as events of regional relevance, making it possible to identify cases for further investigation.So it made sense to conduct a thorough press article search to capture media perspectives on aquatic deweeding.
We searched for press articles using the databases "WISO" and "Library Pressdisplay", along with a generic Google internet search.The search returned a total of 96 relevant articles in 58 different newspapers and other organs of the press.Data was extracted from the articles applying Mayrings's method of qualitative content analysis as described in figure 2 below (Mayring 2015), using the groupings

Opinions on aquatic deweeding
Questionnaire survey 408 respondents

Content analysis of press articles 96 articles
Case studies 6 cases, 24 interviews The resulting data was scanned for arguments about aquatic macrophytes and de-weeding, which were categorized by the stakeholders who stated them.
The arguments voiced by the stakeholders were collected and summarized by their main arguments.

Interviews
To gather deeper insight into cases with the greatest research value, we conducted qualitative interviews (Witzel 2000) with selected stakeholders.Cases were initially screened based on the data gathered through the press article research and questionnaires.We then selected six cases, each exemplary because of the degree of stakeholder interaction about problems with aquatic macrophytes and de-weeding.Table 1 summarizes the selected cases.
Interview partners were selected in a way that we would have at least one of each stakeholder category (see chapter 4 for the stakeholder category list) in every case present.The interviews were carried out by phone using a text guideline and were recorded for transcription.The interviews were analysed using Kuckartz' method of qualitative interview analysis (Kuckartz 2014).During analysis, statements were categorized to get a clear picture of what stakeholders think of "their" river or lake and what functions they assign to it (see Table 2 in Section 4.4). 4 Results

Which stakeholders are affected by aquatic deweeding?
The analysis of press articles and scientific publications leads us to recognize four different stakeholder groups, each having its own set of interests and concerns: 1. Nature Conservation This group consists of stakeholders whose primary concern relates to the conservation and/or restoration of aquatic ecosystems, often correlated with an educational interest.Example stakeholders in this group include nature conservation organizations, regional ecosystem monitoring associations, and nature reserve staff.

Water Construction and Maintenance
This group includes all stakeholders related to technical water-related services.This includes maintenance of water run-off capabilities to serve flood protection and cleaning of hydroenergy water intakes.These stakeholders are mostly municipal authorities or water maintenance associations, so economic reasons are not their primary concern.

Economy and Business
Stakeholders in this group have a foremost economic concern when it comes to rivers and lakes.This group is made up mostly of agricultural stakeholders, who have both strong concerns about flood protection of their riverside fields as well as a demand for irrigation water.Members of this group also include hydropower owners.This group views rivers and lakes mainly from an economic perspective, and its concerns focus on how use of the waterways affects workflow in their members' businesses.Its business-like attitude which sees rivers and lakes mainly as a materialistic resource distinguishes them from stakeholders of group 4, who see economic value of rivers and lakes only in their aesthetic, as part of a recreational landscape.

Tourism and Recreation
This category includes all stakeholders whose primary interest in rivers and lakes is recreational.This does not rule out an economic interest as well, but the recreational value is mostly nondepleting.They were not included in group 3, as their arguments showed a distinction to this group.Especially the leisure fishermen were not in line with the professional fishermen, often calling for non-sustainable de-weeding methods.
Stakeholders of this group are water sports associations, tourism management organizations, but also leisure fishery associations.

What is their opinion on de-weeding?
With respect to our main research questionattitudes toward de-weeding -views held by the nature conservation group stand in clear distinction from those of other stakeholders.While the other stakeholder groups name benefits and advantages of de-weeding to the exclusion of other concerns, nature conservation stakeholders have diverse arguments both for and against the practice.This points to a high potential for conflicts with parties of different stakeholder groups.
The following summarizes stakeholder group opinions gathered from all different sources of data (survey, interviews, press articles and scientific articles):

-Nature Conservation
Broadly speaking, members of the nature conservation stakeholder group oppose deweeding.Their views are differentiated, but high aquatic macrophyte density is generally not seen as problematic.One exception to this regards the robust proliferation of neophytes, e.g.Elodea nuttalii in German waters, recognized as a possible threat to domestic ecosystems (Barrat-Segretain 2005).However, mechanical de-weeding is not seen as a feasible means of controlling the neophytes (Willby 2007).The claim is made that domestic aquatic ecosystems are capable of self-regulation (Perrow et al. 1997;Prejs 1984); a further argument is made that de-weeding would cause greater harm than benefit.This is especially true with respect to the mechanical de-weeding applied to many rivers and lakes (Meyer 2000), which has had many disturbing effects on the ecosystem.The ground is disturbed, causing high levels of suspended particles in the water body.When the aquatic macrophytes are removed, aquatic fauna, sources of food and shelter for water life, are lost (Meyer 2000).When a stream or lake is de-weeded regularly, a lower level of biodiversity results.As a conclusion, this stakeholder group opposes de-weeding, if not for clearly defined aspects of neophyte control.

-Water Construction and Maintenance
The stakeholders of this group see aquatic macrophytes mainly as a nuisance, leading them to favor de-weeding.De-weeding is seen as necessary to ensure the trouble-free functionality of hydropower installations and other technical installations (Chaudhuri & Janaki Ram 1975).Further concerns focus on the security of potable water production (Bode 2014), water level management and wastewater treatment (Arbeitgemeinschaft der Wasserwirtschaftverbände in Nordrheim-Westfalen 2011; Wasserverbandstag e.V.).Stakeholders of this group show a comparatively high level of openness to solutions other than de-weeding, even if this would cause changes in their workflow.

-Economy and Business
The stakeholders who see the issue from an economic and business point of view favor the deweeding of rivers and lakes.They tend to see aquatic macrophytes as a nuisance to be controlled.The agricultural businesses in this group of stakeholders are well organized and do not hesitate to put pressure on the responsible parties to ensure their interests arebeing served.
Many stakeholders of this group only object to mechanical de-weeding in cases where the financial effort does not lead to adequate results.One exception is found in the professional fishing industry, whose members operate in some German lakes.They see aquatic macrophytes as a natural habitat for the fish that drives the industry, so are not keen to have them removed.

-Tourism and Recreation
The stakeholders in this group mostly like nature in its clean and tidyversion, where aquatic macrophytes can have their niche as long as they do not interfere with the group's interests.Unlike groups two and three, members of this group value landscape itself as a positive factor.This leads to a higher tolerance for aquatic macrophytes in rivers and lakes, as they are part of the natural landscape.Tolerance ends where aquatic macrophytes interfere with the activities of the group, especially when economic interests are impaired.This is the case where swimming, boating and other recreational activities suffer from aquatic macrophytes or when the recreational value of a tourist attraction is compromised by the smell of rotting plants (Gutiérrez et al. 1994).
Figure 3 up the arguments voiced by the respective stakeholder groups, where a plus sign indicates an argument in favor of de-weeding and a minus sign indicates an argument against.

Do Stakeholders know other stakeholders being affected and their concerns and what is their perception of nature conservation?
Our research revealed that members of these stakeholder groups are often biased in their perception of the interests of the other groups.
Stakeholders in one group tend to have little knowledge about the needs and interests of stakeholders in another group, as there is little exchange of factual information among groups.This means preconceptions and even prejudice often take the place of rational thought in community debate.This is particularly the case when stakeholders  outside the nature conservation group express their perceptions of stakeholders inside the nature conservation group.In the debates that ensue, concerns of the nature conservation group, which many people still see as an obstacle to the fulfilment of their interests, are often belittled or unfairly portrayed.The following excerpts taken from interviews illustrate.

Water Construction and Maintenance:
People not living beside the river prefer a natural river, where weeds belong as part of nature, except the canoeists, who say: "Aw crap, so many weeds in here, can't go anywhere with my canoe, go and cut me a proper way here." Tourism and Recreational: On the other hand we have nature conservation.They say: Ah, marvelous, wildlife, never seen that much here.So they support this [growth of aquatic macrophytes].But we, the people, are a part of nature as well, aren't we?We need recreation as well, don't we?Nobody thinks of us, right?Tourism and Recreational: From my point of view, there is nothing to raise against de-weeding.Until some genius biologist shows up and presents some type of worm or shell or crab -we do have crabs here, introduced from Canada -which is oh so worthy of protection and in the end cancels any deweeding action.
The examples show a consistent problem in the perception of nature conservation that still exists from the point of view of many stakeholders in the de-weeding debate.

What functions do they attribute to their nearby river or lake?
To evaluate the effect of misperceptions on the de-weeding debate, it helps to see what a river or lake means to the stakeholders, what functions they attribute to a waterway.Table 2 lists all the functions assigned to a river or lake mentioned by the stakeholders.It shows where stakeholder interests are shared and where they are not.While every stakeholder group agrees that rivers and lakes have a recreational value, most stakeholders consider only functions that play a role insatisfying their own interests, leaving out the interests of other stakeholders.

Function of a River or Lake Mentioned by Stakeholder Group
Group 1 1 Group 2 2 Group 3 3 Group 4 4

Discussion
O ur research has identified four distinct stakeholder groups in the aquatic de-weeding debate: stakeholders associated with nature conservation; those associated with water system construction and maintenance; those whose interest in the waterways is primarily economic and businessoriented; and those whose interest revolves around tourism and recreation.
Every stakeholder group shares the view that rivers and lakes are desirable features, adding both recreational and economic value to a landscape.Every stakeholder group readily admits that nature should have its way -up to a point.
That point varies depending on the stakeholder group, and may even be reached in cases by nature conservation (e.g.neophyte control).But it is more frequently reached by members outside the conservation group, when a stakeholder demands, solely on behalf of his or her interests, that the aquatic macrophyte growth be cut back.At this point, if the stakeholder encounters opposition, it is likely to come from a stakeholder in the nature conservation group.Even though the benefits of increased aquatic macrophyte growth for wildlife may be known, and even acknowledged by all parties, stakeholders will not allow those system-wide benefits to outweigh their own specific interests, e.g.waterside residents, boat rentals, agricultural residents.The offended stakeholder takes a demanding position vis-à-vis other stakeholders whom they hold responsible, denying other stakeholders' interests.
Actions taken by the offended stakeholder range from lodging complaints with elected government officials to demanding intervention by water management associations.Other stakeholders' interests here play a minor role and one of the key problems is often not acknowledged: Many of the water management associations have bylaws that restrict their cause of action to the service of very limited interests, generally to ensure flood protection and well-regulated water run-off.
Complications arise when policy changes in water management are implemented without adequate consideration of the diverse stakeholder network affected.How undesired consequences can arise is illustrated by a recent case involving implementation of the EU Water Framework Directive.The directive has led to clearer waters in many rivers and lakes, seemingly a praiseworthy goal.But clearer waters allow more light to reach the waterbeds, which in turn causes an increase in aquatic macrophyte growth.Clearer waters are an obvious benefit, but the consequences are grave for stakeholders who then must suffer excessive aquatic macrophyte populations.
From an ecological standpoint, the widespread attitude of viewing water plants as a mere nuisance, a weed that has to be regulated, bears substantial danger.The ecosystem services offered by a welldeveloped water plant population are essential to the ecosystem and to mankind.The survey has shown a lack of information on the value of water plants that should be addressed.

Conclusions
T he conclusions drawn from this study are threefold: First, our research has identified four distinct stakeholder groups in the de-weeding debate; what is especially notable about these groups is that three of them view de-weeding as almost entirely beneficial, although the perceived benefits depend on the group whose interests are at stake.These stakeholders see no downsides to de-weeding, no reason for caution or moderation; when weeds get in their way, the weeds need to be removed.
The only stakeholders that give any consideration to the disadvantages of de-weeding are those in the nature conservation group together with some of the professional fishermen who see a certain amount of aquatic macrophytes as necessary for fish development.Stakeholders from the Economy group see a disadvantage in de-weeding only by its questionable results, not in its ecological impact.Stakeholders in the nature conservation group are by no means entirely against de-weeding; they simply are the only ones who consider the risks involved.Consequently, their positions tend to be misunderstood by other stakeholders and cast solely as obstructionist.There is no pan-stakeholder acknowledgement of the benefits of an intact aquatic ecosystem for all, leaving the nature conservation group as the lone voice speaking it its defence.This is a key finding, because it points to a communication deficit between stakeholders, a deficit that needs to be addressed so inherent conflicts of interest between stakeholder groups can be brought to the surface and openly negotiated.A solution for this issue could be the instalment of round-table discussion groups with external (unbiased) experts, who could help stakeholders to better understand the importance of aquatic macrophytes and their provision of ecosystem services.
Where possible, a spatial separation of use can help to solve conflict between stakeholders.An example is provided by the Chiemsee region, where a regional management plan integrates every stakeholder's needs.To eliminate conflict potential right from the beginning, it is advised to let the different stakeholders groups and the public participate appropriately in the planning process.
Our second conclusion is that when implementing changes in water management policy, a higher degree of impact assessment is necessary to include all stakeholders' interests.Policy actions that go against key stakeholder interests will quickly come under fire.That is what happened with the EU Water Framework Directive; although the goal was to establish a framework for community action in the field of water policy, the interests of all stakeholders were not considered when carrying out new policy.Specifically, the consequences of policy on the aquatic macrophyte population, and hence on stakeholders in operations of the water bodies, were ignored.
Our third conclusion is that water management authority needs to be clarified.As of today, many water management associations have very limited fields of action that exclude the interests of many stakeholder groups.While some of these interests are often addressed on a casual basis, increased demands cannot be fulfilled with the limited resources of these organizations.A greater participation in the funding of these organizations and an integrated management concept would help to better fulfil the multitude of interests, as examples indicate.Other avenues of aquatic macrophyte control could be explored, including innovative ways of de-weeding such as planting trees at the riverside to enhance shading and thereby inhibit aquatic macrophyte growth.

Table 1
Cases Selected for In-Depth Analyses Titel...