Introduction
Rivers worldwide face serious threats from climate change, pollution, and habitat degradation, prompting coordinated conservation efforts that increasingly rely on citizen engagement (Johnson et al., Reference Johnson, Balmford, Brook, Buettel, Galetti, Guangchun and Wilmshurst2017). Legislative frameworks and policies—such as the EU Water Framework Directive and Biodiversity Strategy for 2030, Australia’s Landcare program, and the US National Environmental Policy Act (NEPA)—aim not only to protect water quality and restore freshwater habitats, but also to promote volunteering and public involvement. Citizen participation plays a vital role, particularly in the protection and restoration of river ecosystems. However, studies have highlighted persistent challenges in recruiting and retaining participants for river-related activities (Koehler & Koontz, Reference Koehler and Koontz2008).
Community-led conservation activities—such as removing invasive species, planting native vegetation, restoring wetlands and stream channels, and engaging in monitoring, education, awareness-raising, or sociopolitical activism—have become widespread and are often driven by local volunteers. These activities are highly varied, and not all volunteers participate in every type. Measham and Barnett (Reference Measham and Barnett2008) categorize environmental volunteer activities into four main types: education, activism, restoration, and monitoring. Each type reflects a distinct way of translating pro-environmental awareness into action, shaped by individual capacities, preferences, traits, and life experiences. While this typology highlights the diversity of environmental volunteering, relatively little research has examined how different activity types relate to specific combinations of volunteers’ initial motivations and perceived barriers. Understanding these combinations is important for designing more effective engagement and retention strategies.
This study addresses this gap by examining environmental volunteering in the Besòs River basin (Barcelona Metropolitan Region, Spain). It focuses on Measham and Barnett’s four types of volunteering activities—education, monitoring, restoration, and activism—to explore: (1) how motivations and barriers differ across types of activities, and (2) how combinations of motivations and barriers can be interpreted across different environmental volunteering activity groups.
Theoretical background
This section reviews the literature on motivations and barriers in environmental volunteering, with a particular focus on river-based contexts. Following Measham and Barnett’s (Reference Measham and Barnett2008) typology, it considers monitoring activities based on environmental data collection, restoration practices aimed at improving ecological conditions, educational and awareness-raising initiatives, and activism intended to influence environmental governance and public opinion. Reviewing these forms of engagement separately helps clarify how motivations and perceived barriers vary across river-based volunteering activities.
Monitoring activities
Research on river-based environmental volunteering has increasingly focused on monitoring activities, particularly within citizen science and institutionally coordinated frameworks. Studies consistently identify environmental concern, learning opportunities, connection to place, and the opportunity to contribute to scientific knowledge as central motivations for participation, especially among younger volunteers (Alender, Reference Alender2016; Church et al., Reference Church, Payne, Peel and Prokopy2019). At the same time, environmental monitoring activities present specific participation barriers. Research on community-based environmental monitoring and citizen science highlights constraints related to time availability, technical complexity, access to resources and skills, intensive data collection requirements, and the lack of feedback or visible outcomes, all of which can undermine sustained participation and volunteer retention (Wehn & Almomani, Reference Wehn and Almomani2019). Earlier work by Roggenbuck et al. (Reference Roggenbuck, Haas, Hall and Hull2001) similarly found that time constraints and insufficient feedback limited long-term retention in river monitoring programs despite strong pro-environmental motivations. However, the structured nature of many monitoring programs may also reduce perceived barriers by externalizing organizational complexity through standardized protocols, training, and institutional support (Wehn & Almomani, Reference Wehn and Almomani2019).
Restoration activities
Restoration activities are comparatively less studied in river-specific volunteering contexts. Existing research highlights experiential and place-based motivations, with volunteers driven not only by environmental concern but also by the opportunity to improve valued river environments through collective action actively (Lukacs & Ardoin, Reference Lukacs and Ardoin2013). Broader studies on environmental stewardship and landcare-type initiatives similarly emphasize emotional attachment to place, ecological identity, enjoyment of outdoor activities, social interaction, and personal development as important motivations sustaining participation (Bruyere & Rappe, Reference Bruyere and Rappe2007; Caissie & Halpenny, Reference Caissie and Halpenny2003; Gooch, Reference Gooch2005). Reported barriers include slow or limited visible ecological improvements, which may reduce motivation over time, as well as practical constraints such as time availability and logistics.
Education activities
Educational and awareness-raising forms of environmental volunteering remain relatively understudied as distinct categories of engagement and are often embedded within broader stewardship or community-based initiatives. Existing research suggests that volunteers are motivated by opportunities to share knowledge, raise environmental awareness, strengthen community engagement, and contribute to future generations (Gooch, Reference Gooch2005; O’Brien et al., Reference O’Brien, Townsend and Ebden2008). Participation is also associated with learning, skill development, social interaction, and personal empowerment through involvement in environmental stewardship and community action. At the same time, barriers such as insufficient training, limited institutional support, lack of resources, low confidence, and difficulties reaching broader publics may constrain participation and long-term engagement (Gooch, Reference Gooch2005; O’Brien et al., Reference O’Brien, Townsend and Ebden2008).
Activism
Compared to other activity types, river-related activism remains underexplored. Broader research on environmental activism suggests that participation is often driven by environmental values, collective action orientations, and the desire to influence environmental governance and decision-making processes (Bamberg et al., Reference Bamberg, Rees and Seebauer2015; Stern, Reference Stern2000). Recent research also highlights the interplay of cognitive, affective, and behavioral dimensions, emphasizing the role of values, emotions, and perceived efficacy in shaping environmental activism (Van Speybroeck et al., Reference Van Speybroeck, Steen and Derudder2024). Within river-based contexts, emerging research similarly indicates that participation is motivated not only by environmental concern but also by efforts to address perceived gaps in environmental governance and strengthen community resilience (Gearey & Ravenscroft, Reference Gearey and Ravenscroft2019). Activism often involves locally embedded, community-led initiatives, but may also entail challenges such as conflict, political complexity, emotional burden, and sustained organizational demands.
Despite the growing body of research, important limitations remain. The literature is unevenly distributed across activity types, with monitoring—largely through citizen science—receiving substantially greater attention than other forms of environmental volunteering. While restoration, education, and activism have also been examined in broader environmental stewardship and participation research, they remain comparatively underexplored in river-based volunteering contexts and are rarely analyzed comparatively within a shared analytical framework. In addition, existing research is fragmented. Some studies focus on specific activities, most commonly monitoring, while others examine broader watershed or community-based initiatives without differentiating between types of engagement. As a result, current knowledge provides detailed but disconnected insights, limiting our understanding of how motivations and perceived barriers vary across different forms of river-based environmental volunteering within the same context.
This limitation is particularly relevant given that river conservation relies on a combination of activities, ranging from monitoring and restoration to education and activism. Different activities are likely to attract volunteers with distinct motivations, perceived barriers, and participation patterns, yet few studies have examined these differences within a unified analytical framework and context that enables systematic comparison across activity types.
Building on this gap, the present study adopts an activity-based perspective to examine river-based environmental volunteering. Specifically, it investigates how motivations and perceived barriers differ across monitoring, restoration, education, and activism activities, and how combinations of these factors can be interpreted across different environmental volunteering activity groups. By integrating insights across activity types, this approach provides a more nuanced understanding of participation and offers a basis for designing more targeted and effective strategies for volunteer recruitment and retention.
Methods
Setting
This study focuses on the Besòs basin, located in the Barcelona Metropolitan Region of northeastern Spain. Home to over 2 million residents across 54 municipalities, the basin includes more than 200 kilometers of watercourses, notably the Besòs River and its 5 main tributaries: the Ripoll, Caldes, Tenes, Congost, and Mogent. These range from natural streams to heavily modified channels, many of which have undergone significant ecological restoration following decades of industrial pollution and urban encroachment. This legacy of degradation, combined with sustained community advocacy, has made the Besòs basin a hub for grassroots environmental action. Numerous local groups are engaged in river restoration, water quality monitoring, and environmental education (Benages-Albert & Vall-Casas, Reference Benages-Albert and Vall-Casas2014). Initial fieldwork identified 37 local entities and volunteer groups active in conservation, underscoring the depth and breadth of community commitment to protecting the watershed (Figure 1). These groups were identified through a combination of systematic online searches, consultation with regional basin-level institutions (e.g., the Consorci Besòs), and a snowball approach, whereby contacted organizations were asked to identify additional active groups.
Map of the Besòs River basin with sub-basins and locations of the 37 local environmental groups.
Fig. 1. Long description
A geographical map overlaying a topographical terrain. The Besòs River basin is divided into six distinct colored regions representing sub-basins.
* The Tenes sub-basin is blue and runs vertically through the North-Central section.
* The Congost sub-basin is green and runs vertically through the North-East section.
* The Mogent sub-basin is yellow and occupies the Eastern edge.
* The Caldes sub-basin is orange and is located in the West-Central section.
* The Ripoll sub-basin is pink and occupies the Western edge.
* The Besòs sub-basin is purple and is located at the Southern base where the rivers converge toward the coast near Barcelona.
Green pin markers represent environmental entities or groups. Most pins are individual, but some contain numbers indicating multiple groups in one location.
* In the North, pins are scattered sparsely in Tenes and Congost.
* In the Central region, pins are clustered around Caldes de Montbui and Granollers, with a marker labeled 3 in the Congost area.
* In the South-West, a high density of pins is found around Sabadell and Santa Perpètua de Mogoda, including markers labeled 2 and 3.
* In the South, near the river mouth, markers labeled 4 and 2 are positioned in the purple Besòs zone, with final pins located near the coast in Barcelona.
Data collection and analysis
This exploratory quantitative study used a structured questionnaire as the primary data collection tool (Supplementary Material). It assessed volunteer motivations, perceived barriers, and demographic and volunteering profile characteristics (e.g., age, gender, education, years of volunteering, and volunteer frequency), which are used to describe the sample (see Table 1) and support the interpretation of results. Respondents were classified into one of four activity types based on their self-reported main involvement: (1) sociopolitical activism (focused on systemic change through advocacy, media engagement, and support for reforms), (2) environmental restoration (hands-on activities such as tree planting, litter clean-ups, and other actions aimed at improving natural habitats and ecosystems), (3) environmental monitoring (activities like monitoring water quality, species observation, and data collection for conservation), and (4) outreach and education (activities such as guided walks, talks, and events to promote environmental awareness).
The instrument included 17 motivation items and 15 barrier items, each measured on a 5-point Likert scale from 1 (not important at all) to 5 (very important). An initial pool of items was derived from prior empirical studies on environmental volunteering (Bruyere & Rappe, Reference Bruyere and Rappe2007; Byron & Curtis, Reference Byron and Curtis2002; Font & Navarro, Reference Font and Navarro2013; OECD, 2015; Ryan et al., Reference Ryan, Kaplan and Grese2001; van der Heijden et al., Reference van der Heijden, ten Heuvelhof, Broekhans, van der Arend, van Bueren, Harteveld and van Ruijven2014), and subsequently refined through a Delphi consultation with experts, followed by a focus group with local volunteers to ensure clarity, relevance, and contextual adequacy.
Motivations were organized into six thematic categories: (1) environmental concern, (2) social relations, (3) learning, (4) personal fulfilment, (5) introspection, and (6) career development—drawing on commonly identified motivational dimensions in environmental volunteering research (e.g., Ryan et al., Reference Ryan, Kaplan and Grese2001). Barriers were grouped into four thematic categories: (1) personal constraints, (2) contextual limitations, (3) group-related dynamics, and (4) activity-related obstacles—following classifications proposed by Byron and Curtis (Reference Byron and Curtis2002). While several items closely reflect those used in previous studies (e.g., time constraints and lack of institutional support), others were contextually adapted to better capture the specificities of river-based volunteering. In particular, the motivation item “to help improve a place I love” builds on place-based motivations identified in previous research (e.g., Bruyere & Rappe, Reference Bruyere and Rappe2007) but was adapted to emphasize place attachment as highlighted in prior qualitative studies in the study area (Benages et al., Reference Benages-Albert, Di Masso, Porcel, Pol and Vall-Casas2015, Reference Benages-Albert, Vidal, Pol and Vall Casas2023). Similarly, the barrier “too many greenwashing strategies” emerged inductively from the focus group as a locally salient concern not explicitly captured in previous instruments. A pilot test with six volunteers experienced in both volunteering and survey research was conducted, meeting recommended guidelines for instrument pretesting and content validation (Boateng et al., Reference Boateng, Neilands, Frongillo, Melgar-Quiñonez and Young2018). The aim of the instrument was not to develop a standardized psychometric scale, but to identify patterns of motivations and perceived barriers across activity types.
The survey was approved by the Ethics Committee of Universitat Internacional de Catalunya and targeted 37 local entities and volunteer groups identified in the Besòs basin, representing 925 active river-oriented volunteers. It was distributed via Google Forms in July 2021, with a follow-up reminder in September. The survey link was shared through these organizations, which disseminated it via their internal communication channels (e.g., mailing lists or newsletters), ensuring targeted distribution through nonpublic networks rather than open platforms. No financial or material incentives were offered, reducing exposure to automated or fraudulent responses. A total of 125 responses were received, yielding a 13.5% response rate—within the typical range of 10–25% for complex online surveys (Sauermann & Roach, Reference Sauermann and Roach2013). While login was not required to preserve accessibility and participant anonymity, responses were screened for data quality, including checks for duplicate or highly similar response patterns and internal inconsistencies. No responses met exclusion criteria on these grounds, and no evidence of duplicate submissions was identified. No personally identifiable information (e.g., names, email addresses, or IP addresses) was collected. Participant demographics and experience profiles align with other case studies on environmental volunteering in Spain, particularly in terms of gender distribution, age structure, and high levels of education commonly reported among environmental volunteers (SEO/BirdLife, 2020). The sample offers valuable insights into the Besòs River basin and serves as a representative example of grassroots volunteer activity in Euro-Mediterranean urban river corridors.
Descriptive statistics were used to summarize participants’ sociodemographic characteristics, type of volunteering activity, initial motivations, and perceived barriers. Categorical variables were described using frequencies and percentages. Differences in sociodemographic characteristics across volunteering activity types were assessed using chi-square tests or Fisher’s exact tests, as appropriate. Initial motivations and perceived barriers were analyzed using linear regression models, and results were reported as adjusted marginal means and standard errors according to volunteering activity type. Models were adjusted for potential confounders, including gender, age, educational level, years of volunteering experience, and volunteering frequency. Adjusted marginal means were compared using analysis of variance (ANOVA), and pairwise comparisons were corrected using Tukey’s method. Statistical significance was set at a p-value <0.05. All analyses were performed using R software.
Assuming a conservative explained variance of R 2 = 0.10 for the linear regression models, the sample size of 125 participants (13.5% of the target population of 925) provided ~85% statistical power to detect statistically significant associations. The selected R 2 was used as a conservative planning assumption rather than an expected effect size.
Results
Participants’ characterization by type of activity
Table 1 summarizes the sociodemographic characteristics of participants according to the type of environmental volunteering activity performed. Overall, participants were predominantly men (50.4%), aged 30–59 years (64.0%), and had a higher education degree (63.2%). The most common volunteering profile corresponded to participants with 1–5 years of volunteering experience (36.8%) and occasional participation (46.4%). Outreach and education was the most frequently reported activity type (34.4%).
Sociodemographic characteristics of participants by type of environmental volunteering activity
Table 1. Long description
The table presents data for 125 total participants across four activity categories. The overall distribution is: Sociopolitical activism 24 (19.2 percent), Environmental observation 30 (24.0 percent), Outreach and education 28 (22.4 percent), and Environmental restoration 43 (34.4 percent).
* Gender (p-value Fisher test = 0.001): Women represent 45.6 percent of the total, with their highest participation in Environmental restoration (53.5 percent). Men represent 50.4 percent, with their highest participation in Environmental observation (60.0 percent).
* Age (p-value Fisher test = 0.020): The 30 to 59 age group is the largest (64.0 percent), peaking at 72.1 percent in Environmental restoration. Those over 60 are most active in Sociopolitical activism (37.5 percent).
* Education (p-value Fisher test = 0.120): Higher education is the most common level (63.2 percent), followed by Secondary (33.6 percent) and Primary (3.2 percent).
* Years of volunteering (p-value Fisher test = 0.553): The largest groups are those with 1 to 5 years (36.8 percent) and over 10 years (34.4 percent) of experience.
* Volunteer frequency (p-value chi-square test = 0.552): 46.4 percent volunteer occasionally, 28.0 percent weekly, and 25.6 percent 1 to 2 times per month.
Significant differences in gender distribution were observed according to activity type (Fisher’s exact test, p = 0.001). Men were more highly represented in environmental observation activities (60.0%), whereas women showed the highest participation in outreach and education activities (53.5%). Significant differences were also found according to age. Participants younger than 30 years were more represented in environmental observation activities (20.0%), participants aged 30–59 years showed the highest representation in outreach and education activities (72.1%), and participants older than 60 years were more frequently involved in sociopolitical activism (37.5%).
Motivations and barriers by type of activity performed
Participants rated their initial motivations and perceived barriers on a 5-point Likert scale (1 = not important at all; 5 = very important). Tables 2 and 3 summarize the adjusted marginal means and standard errors for motivations and barriers across the different types of environmental volunteering activities. For transparency, Supplementary Tables S1 and S3 present the corresponding unadjusted and adjusted means, whereas Supplementary Tables S2 and S4 report the full regression models, including the estimated effects of the adjustment covariates.
Initial motivations for participation according to type of environmental volunteering activity adjusted to linear regression model
Table 2. Long description
The table presents marginal means and standard errors for 17 motivation items across different volunteering categories.
* Header: Columns include Initial motivations, Overall, Activism, Monitoring, Education, Restoration, and p-value.
* Total Score: Overall 58.4 (1.0). Education has the highest total (62.7) and Activism the lowest (52.1), with a p-value of 0.027.
* Environmental concern (Items 1-3): High scores across all groups (4.26 to 4.68), with no significant differences (p > 0.05).
* Social relations (Items 4-6): Item 5 (collaborate with common interests) shows significant differences (p = 0.008), with Education (4.52) scoring higher than Activism (3.67).
* Learning (Items 7-8): Item 7 (observe nature) shows significant differences (p = 0.004), where Activism (3.52) is significantly lower than Monitoring (4.42), Education (4.48), and Restoration (4.25).
* Personal fulfillment (Items 9-12): Significant differences in Item 11 (have fun, p = 0.007) and Item 12 (physical effort, p = 0.014), with Activism scoring lowest in both.
* Introspection (Items 13-15): Scores range from 1.71 to 4.18, with no significant differences.
* Career development (Items 16-17): Item 16 (help professional career) shows significant differences (p = 0.004), with Monitoring (2.71) scoring higher than Activism (1.68).
Note: Values are presented as adjusted marginal means and standard errors obtained from linear regression models adjusted for gender, age, education, years of volunteering, and volunteer frequency. Different superscript letters (a, b) indicate statistically significant differences between activity groups based on Tukey’s post-hoc test (p < 0.05).
Perceived barriers to participation according to type of environmental volunteering activity, adjusted in a linear regression model
Table 3. Long description
The table presents marginal means and standard errors for 15 barrier items across different volunteering types. The columns are Overall, Activism, Monitoring, Education, Restoration, and p-value.
* Total Score: Education has the highest perceived barriers at 44.5, while Monitoring has the lowest at 36.1 (p = 0.016).
* Personal constraints: Item 3 (Frustration/fatigue) and Item 4 (Lack of knowledge) show significant differences. Education volunteers report the highest frustration (2.69) compared to Monitoring (1.72) and Restoration (1.85).
* Contextual limitations: Item 5 (Lack of institutional recognition) and Item 6 (Dealing with administration) are significantly higher for Education (3.69 and 3.97 respectively) compared to Monitoring and Restoration.
* Group-related dynamics: Items 9 through 12 (Disorganization, Lack of resources, Lack of leadership, Feeling undervalued) show no statistically significant differences between groups, though Education consistently scores higher in resource and leadership concerns.
* Activity-related obstacles: Item 13 (Volatile nature of improvements) is significantly higher for Education (3.16) and Activism (3.11) compared to Monitoring (2.45) and Restoration (2.50).
Note: Superscript letters a and b denote statistically significant differences based on Tukey’s post-hoc test.
Note: Values are presented as adjusted marginal means and standard errors obtained from linear regression models adjusted for gender, age, education, years of volunteering, and volunteer frequency. Different superscript letters (a, b) indicate statistically significant differences between activity groups based on Tukey’s post-hoc test (p < 0.05).
Table 2 shows participants’ initial motivations by activity type. Overall, the highest mean scores across the four activity types were observed for the environmental concern category, particularly for the items “To see improvements in the natural environment” (4.52 ± 0.08) and “To help preserve the natural environment for future generations” (4.50 ± 0.08). Similarly, consistently high scores were observed for the item “To learn about nature” (4.34 ± 0.09), belonging to the learning category. In contrast, the lowest scores were observed for the item “For spirituality” (2.01 ± 0.10) and for the career development category (2.08 ± 0.11 and 2.70 ± 0.13). Figure 2 illustrates the adjusted marginal mean scores for motivations according to volunteering activity type.
Adjusted marginal mean scores (± standard error) for motivations according to volunteering activity type.
Fig. 2. Long description
A dot plot displays Mean plus or minus Standard Error scores on an X-axis ranging from 1 to 5. The Y-axis lists sixteen motivations. A legend at the top identifies four activity types: Activism (pink), Monitoring (green), Education (teal), and Restoration (purple).
Top motivations with the highest scores (between 4 and 5) for all groups include:
* To see improvements in the natural environment.
* To be able to help improve a place I love.
* To help preserve the natural environment for future generations.
Motivations with moderate scores (between 3 and 4) include:
* To collaborate with people with common interests.
* To observe nature.
* To learn about nature (plants, animals, etc.).
* To feel useful.
* Because I feel responsible for the river.
* To have fun.
* Because it invites me to reflect.
* Because it makes me feel good.
Motivations with the lowest scores (between 1.5 and 3.5) include:
* On the recommendation of a family member or friend.
* To meet people.
* Because it involves physical effort in contact with nature.
* For spirituality.
* Because it can help my professional career.
* To stay in touch with topics that interest me professionally.
Across most categories, Education (teal) and Restoration (purple) tend to score higher than Activism (pink). The motivation ‘To help preserve the natural environment for future generations’ shows the highest mean score for the Education group, approaching 5.
Statistically significant differences in total motivation scores were observed according to activity type (p = 0.027). Participants involved in outreach and education activities showed the highest overall motivation score (62.7 ± 2.3), whereas those engaged in sociopolitical activism reported the lowest score (52.1 ± 2.4). Within the social relations category, a significant difference was found for the item “To collaborate with people with common interests” (p = 0.008), with higher scores among participants involved in outreach and education compared with those engaged in sociopolitical activism. In the learning category, significant differences were observed for the item “To observe nature” (p = 0.004). Participants involved in environmental monitoring, outreach and education, and environmental restoration reported higher scores than those participating in sociopolitical activism. Within the personal fulfilment category, significant differences were identified for the items “To have fun” (p = 0.007) and “Because it involves physical effort in contact with nature” (p = 0.014). In both cases, participants involved in outreach and education and environmental restoration reported higher scores than those engaged in sociopolitical activism. In the career development category, a significant difference was found for the item “Because it can help my professional career” (p = 0.004), with higher scores among participants involved in environmental monitoring compared with those engaged in sociopolitical activism. No statistically significant differences were observed for the remaining motivations.
Table 3 presents the perceived barriers to participation in environmental volunteering according to activity type. Overall, the highest barrier scores across the four activity types were observed in the contextual limitations category, particularly for the items “Lack of public awareness on environmental issues” (3.48 ± 0.12) and “Dealing with the administration (bureaucracy, politicization, delays, etc.)” (3.25 ± 0.13). Similarly, high scores were also observed for the item “Lack of time due to work reasons” (3.10 ± 0.12), belonging to the personal constraints category. In contrast, the lowest scores were reported for the item “Feeling undervalued or ignored by the group” (1.73 ± 0.10), belonging to the group-related dynamics category, and for the item “Not enjoying/not feeling good about the type of activities to be carried out” (1.90 ± 0.11), belonging to the activity-based obstacles category.
The overall analysis revealed statistically significant differences in total barrier scores across activity types (p = 0.016). Participants involved in education reported the highest overall barrier score (44.5 ± 2.3), whereas those engaged in restoration (37.0 ± 1.8) and environmental monitoring (36.1 ± 2.2) showed lower scores. However, Tukey-adjusted pairwise comparisons did not identify statistically significant differences between specific activity types.
Within the personal constraints category, significant differences were found for the items “Frustration and/or fatigue (initial expectations too high)” (p = 0.009) and “Lack of knowledge and/or specific skills” (p = 0.012). In both cases, participants involved in education reported higher scores (2.69 ± 0.24 and 2.42 ± 0.19, respectively) than those engaged in restoration (1.85 ± 0.18 and 1.73 ± 0.15, respectively). Regarding the contextual limitations category, significant differences were observed for the items “Lack of institutional recognition/support” (p = 0.011) and “Dealing with the administration (bureaucracy, politicization, delays, etc.)” (p = 0.013). In both items, participants involved in education reported higher scores (3.69 ± 0.29 and 3.97 ± 0.29, respectively) than those engaged in environmental monitoring (2.60 ± 0.28 and 2.77 ± 0.27, respectively) and environmental restoration (2.67 ± 0.23 and 2.98 ± 0.22, respectively). A consistent descriptive pattern was also observed across the personal constraints and contextual limitations categories, with participants involved in activism reporting the second-highest mean scores across all items, after those involved in education (Figure 3).
Adjusted marginal mean scores (± standard error) for perceived barriers according to volunteering activity type.
Fig. 3. Long description
A dot plot displays Mean plus or minus Standard Error for 14 perceived barriers. The X-axis represents the score from 1 to 5. The Y-axis lists barriers. A legend at the top identifies four activity types: Activism (red), Monitoring (green), Education (teal), and Restoration (purple).
Key data trends from top to bottom:
* Lack of time due to work reasons: All groups score high, between 2.5 and 3.2.
* Frustration and/or fatigue: Scores are clustered around 2.7 to 3.3.
* Lack of knowledge and/or specific skills: Monitoring and Activism score lowest (under 2.5), while Restoration and Education are higher.
* Dealing with the administration: Education shows the highest barrier score here, near 3.8.
* Lack of public awareness on environmental issues: Education and Restoration report higher barriers (3.0 to 4.0) than Monitoring and Activism.
* The volatile nature of the improvements achieved: This is the lowest-rated barrier across all groups, with scores between 1.5 and 2.0.
* Not enjoying / Not feeling good about the type of activities: Scores are low, generally between 1.7 and 2.3.
Horizontal lines through each dot represent the standard error, showing the variance in responses for each activity type within each barrier category.
Within the activity-related obstacles category, a significant difference was found for the item “The volatile nature of the improvements achieved” (p = 0.026), with higher scores among participants involved in education (3.16 ± 0.25) and activism (3.11 ± 0.27) compared with environmental monitoring (2.45 ± 0.27) and environmental restoration (2.50 ± 0.20). However, pairwise comparisons did not reveal statistically significant differences between activity types after Tukey adjustment. No statistically significant differences were observed for group-related dynamics or for the remaining items.
Discussion
Interpreting motivations through an activity-based lens
Consistent with previous research (e.g., Lukacs & Ardoin, Reference Lukacs and Ardoin2013), environmental concern—particularly motivations related to preserving nature for future generations and contributing to environmental improvement—emerges as a cross-cutting category across all activity types. Similarly, learning about nature appears as a shared motivation across environmental volunteering.
However, moving beyond this common core, the results reveal clear differentiation in motivational patterns between activity types, supporting the value of an activity-based perspective.
Volunteers involved in outreach and education activities can be characterized as community-oriented educators, consistent with prior research identifying social interaction, learning, and community engagement as key motivations (O’Brien et al., Reference O’Brien, Townsend and Ebden2008). This study suggests that collaboration is not merely a complementary motivation, but a defining feature of education-oriented volunteering, encompassing both knowledge transmission and collective relational environmental engagement (Krasny & Tidball, Reference Krasny and Tidball2012).
Volunteers involved in environmental monitoring activities can be characterized as career-oriented learners, consistent with existing citizen science literature identifying learning and contribution to scientific knowledge as central motivations (Alender, Reference Alender2016). This study further highlights the coexistence of environmental (“To observe nature”) and instrumental (“To help my professional career”) motivations within this volunteering profile. While environmental volunteering has often been described as primarily driven by environmental and conservation values (Bruyere & Rappe, Reference Bruyere and Rappe2007), our findings suggest that environmental monitoring may reflect a more hybrid orientation combining environmental interest, learning, and career development.
Volunteers involved in environmental restoration activities can be characterized as action-focused restorers, consistent with previous findings on place attachment and experiential engagement (Gooch, Reference Gooch2005; Lukacs & Ardoin, Reference Lukacs and Ardoin2013). This study shows that experiential engagement is closely linked to personal fulfilment motivations, particularly “To have fun” and “Because it involves physical effort in contact with nature.” The enjoyment derived from hands-on practice as an immediately rewarding activity, previously noted in the literature (Gooch, Reference Gooch2005; Ryan et al., Reference Ryan, Kaplan and Grese2001), appears to be a defining feature of environmental restoration volunteering.
Volunteers involved in environmental activism can be characterized as advocacy-driven volunteers. Previous research suggests that activism is primarily motivated by environmental values and concerns about systemic change (Bamberg et al., Reference Bamberg, Rees and Seebauer2015; Stern, Reference Stern2000). This study found a lower prevalence of motivations related to direct contact with nature, such as “To observe nature,” “To have fun,” and engaging in “Physical effort in contact with nature,” compared with the other activity types. These findings suggest a potential decoupling between environmental values and experiential engagement with nature, characteristic of environmental activism strongly oriented toward systemic change. This contrasts with dominant narratives in environmental volunteering, which often emphasize emotional and place-based connections to nature as a common underlying feature.
Interpreting barriers through an activity-based lens
Consistent with prior studies, barriers to participation across all activity types reflect a combination of contextual and personal constraints, including time limitations, bureaucratic complexity, and lack of public awareness. These findings align with broader literature on volunteer retention and organizational support (e.g., Byron & Curtis, Reference Byron and Curtis2002).
However, when examined through an activity-based lens, important differences emerge between activity types.
Volunteers involved in outreach and education activities report the highest levels of barriers, particularly those related to institutional recognition and emotional strain. Previous research has identified organizational and management challenges in environmental volunteering, including insufficient support, limited public awareness, and volunteer burnout (O’Brien et al., Reference O’Brien, Townsend and Ebden2008). Consistent with these findings, the present study suggests a more specific dynamic within education-oriented activities, which appear to involve substantial relational and communicative demands. When adequate recognition and support are lacking, these demands may generate significant emotional and institutional pressures.
Volunteers involved in restoration activities exhibit the lowest levels of emotional and institutional barriers. This aligns with previous research suggesting that structured, hands-on environmental activities facilitate engagement by providing clear roles, achievable goals, and visible outcomes (Byron & Curtis, Reference Byron and Curtis2002). The findings further suggest that restoration may function as a low-friction entry point into environmental volunteering, as its clarity of purpose and tangible results may reduce participation barriers. This indicates that restoration activities could play a strategic role in recruitment, particularly for individuals deterred by more complex or abstract forms of participation.
Volunteers involved in environmental monitoring activities report comparatively low levels of contextual barriers, particularly regarding institutional support and bureaucracy, as well as fewer activity-related obstacles, especially concerning the perceived volatility nature of achieved improvements. Previous research on community-based monitoring programs (Wehn & Almomani, Reference Wehn and Almomani2019) has identified time demands and technical constraints as key barriers to participation. However, the structured nature of monitoring programs—characterized by standardized protocols, training, and organizational support—may help make these constraints more manageable for volunteers while providing a clearer and more stable sense of progress and achievement.
Finally, volunteers involved in sociopolitical activism report high levels of contextual barriers, including lack of institutional support, bureaucracy, limited public awareness and greenwashing, as well as personal constraints such as frustration and fatigue. These findings align with previous research describing environmental activism as closely linked to systemic change and institutional conflict (Bamberg et al., Reference Bamberg, Rees and Seebauer2015; Gearey & Ravenscroft, Reference Gearey and Ravenscroft2019). As a result, activism may involve greater emotional strain and sustained pressure, requiring stronger ideological commitment to persist despite systemic resistance and public disengagement.
Toward an integrated theoretical understanding of river-based environmental volunteering
This study contributes to theory building in environmental volunteering by showing, through an activity-based perspective, that river-related environmental volunteering is not a unitary practice, but rather a constellation of distinct activity types—monitoring, restoration, education, and activism— each characterized by distinct patterns of motivations and barriers associated with volunteers engaged in different activity types.
These findings are consistent with established theories of environmental volunteering. According to Clary and Snyder’s (Reference Clary and Snyder1999) Functional Theory, volunteer activities fulfil different psychological functions, including values expression, understanding, social connection, career development, protection, and enhancement. In this context, restoration activities appear primarily associated with personal fulfilment and emotional reward through direct contact with nature, whereas monitoring is more closely linked to learning and career development through knowledge acquisition. Education-oriented activities align more strongly with social connection and collective meaning-making, while activism is mainly associated with values expression and advocacy.
A similar pattern emerges in relation to Deci and Ryan’s (Reference Deci and Ryan2000) Self-Determination Theory, which proposes that human motivation is shaped by the fulfilment of three core psychological needs: autonomy, competence, and relatedness. Restoration and activism appear more strongly associated with autonomy, through direct action and alignment with personal values, respectively. Monitoring is more closely related to competence through skill and knowledge acquisition, whereas education activities emphasize relatedness through collaboration and social interaction.
Overall, both theoretical frameworks suggest that individuals engage in volunteering to satisfy different psychological needs and goals. The activity-based perspective developed in this study contributes to this literature by linking specific activity types to distinct motivational patterns, thereby refining current understandings of environmental volunteering.
Importantly, this study also suggests that barriers should not be conceptualized merely as obstacles to participation independent of activity type. Rather, motivations and barriers appear to be closely interconnected and associated with different river-based volunteering activity types.
The high emotional and institutional barriers reported by educators and activists, for example, may reflect the relational demands and need for social recognition associated with education-oriented activities, and the conflict inherent in pursuing systemic change in activism. In contrast, the lower barriers reported by restorers and monitoring volunteers may stem from the alignment between motivations and activity characteristics. Restoration activities provide direct contact with nature and tangible environmental improvements, whereas monitoring activities offer a structured and competence-oriented framework that may reduce perceived constraints.
Although these interpretations remain exploratory, they highlight the potential of activity-based approaches to provide a more integrated understanding of motivations and barriers within environmental volunteering.
Guidance for designing volunteer engagement and retention programs
Strengthening volunteer engagement and retention requires addressing both shared and activity-specific motivations and barriers. The findings support moving beyond one-size-fits-all approaches toward differentiated engagement strategies adapted to the characteristics and demands of different volunteering activities.
Building environmental values early in life and making volunteer contributions visible and meaningful are essential across all activity groups. A strong commitment to ecological preservation—and, in most cases, a desire to learn about nature—emerges as a common motivational base, rooted in personal and collective pro-environmental values shaped through family, education, and early contact with nature. Thus, fostering these values from an early age—through education, family influence, and nature experiences—is key to building long-term engagement (Benages-Albert et al., Reference Benages-Albert, Vidal, Pol and Vall Casas2023).
Colliding with these motivations, common barriers such as time constraints, limited public awareness, bureaucratic complexity, and greenwashing may reduce volunteers’ capacity to act, especially among working-age participants, and weaken trust and perceived impact. Addressing these barriers calls for flexible scheduling, well-defined roles, clear communication (VolunteerHub, 2023), public recognition, and opportunities for feedback and institutional legitimacy (Alender, Reference Alender2016; Krasny & Tidball, Reference Krasny and Tidball2012). These measures may help align volunteer expectations with participation experiences and strengthen retention.
Beyond these general recommendations, the findings suggest the following activity-specific recommendations:
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1) Outreach and education activities: simplifying administrative processes, clarifying roles, and offering communication training—since their tasks often involve permits, events, and institutional coordination—and ensuring support to mitigate bureaucratic and emotional burdens. Given volunteers’ strong orientation toward collaboration and visible outcomes, programs should foster social interaction and provide feedback mechanisms—such as community participation, institutional follow-up, or visible indicators of progress—that reinforce their sense of purpose, even when broader impacts like environmental awareness are only observable in the long-term.
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2) Environmental monitoring: emphasizing opportunities to contribute to scientific knowledge, alongside access to training, certifications, and research collaboration that reinforce skill development and career-oriented motivations. Clearly communicating how volunteer-generated data informs conservation or management decisions may strengthen volunteers’ sense of impact and legitimacy. Although participants in monitoring activities report few systemic barriers, time constraints due to work or study are common—offering flexible, low-commitment roles (e.g., self-paced or modular tasks) and well-structured participation formats may help accommodate these constraints and support long-term engagement.
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3) Sociopolitical activism: streamlining procedures and expanding access to policymaking forums to strengthen volunteers’ sense of agency, while formally recognizing and including them in decision-making processes to support long-term commitment. Supporting campaign work, policy research, and public communication—activities that offer clear channels for structural influence—can further align with their advocacy-driven engagement. Reducing bureaucratic obstacles and improving transparency may additionally reinforce trust and sustained participation.
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4) Environmental restoration activities: supporting logistical needs and practical organization required by river restoration tasks, and reinforcing motivation through visible progress—such as milestones in invasive species removal or habitat recovery. Given volunteers’ strong emotional bond with local ecosystems and desire for tangible environmental impact, these markers should not only demonstrate results but also deepen place attachment by showing that their actions directly contribute to the care of valued environments.
Limitations and future research
This study has several limitations that should be acknowledged. First, the research is based on a case study conducted in a Mediterranean river basin located within a densely populated urban region, which may limit the generalizability of the findings to other geographical or socio-environmental contexts. At the same time, this type of setting—characterized by a history of environmental degradation, ongoing ecological restoration, and strong community involvement—is not unique, and similar conditions can be found in many urban river systems worldwide. The study therefore provides context-specific insights that may nevertheless be transferable to other contexts involving community-based river conservation initiatives.
Second, the classification of volunteers into activity groups is based on self-reported primary engagement and may not fully capture the diversity of participation, as some volunteers may be involved in multiple types of activities simultaneously. Nevertheless, participants in this context tended to identify primarily with a specific form of engagement, which supports the analytical usefulness of this categorization.
Third, the study relies on self-reported motivations and perceived barriers, which may be influenced by social desirability bias or individual interpretation. In addition, certain barriers—such as administrative procedures or bureaucracy—may be experienced differently depending on volunteers’ level of involvement (e.g., participants versus organizers), which should be considered when interpreting activity-specific findings.
Fourth, no adjustment for multiple testing was applied across questionnaire items. Therefore, the reported statistically significant findings should be interpreted with caution because of the increased risk of type I error.
Further research is needed to examine the applicability of these findings across other environmental and sociocultural contexts, as well as to explore through longitudinal studies how such patterns may evolve over time. Alternative methodological approaches, such as latent profile analysis, could also help validate, refine, and extend the activity-based perspective proposed here.
Conclusion
This article explored the motivations and barriers faced by volunteers involved in different river-based environmental activities to inform more effective engagement and retention programs. The findings highlight the heterogeneous nature of river-based environmental volunteering, showing how patterns of motivations and barriers vary according to activity type. This provides a conceptual basis for understanding environmental volunteering as a diverse set of activity-based forms of engagement.
The study characterized four distinct volunteering profiles associated with different activity types: volunteers involved in outreach and education activities can be characterized as community-oriented educators, participants engaged in environmental monitoring as career-oriented learners, volunteers involved in sociopolitical activism as advocacy-driven volunteers, and those engaged in restoration activities as action-focused restorers. All groups shared a strong environmental concern, while common barriers included limited public awareness, greenwashing, and time constraints. At the same time, important differences were observed across activity types. Educators faced the highest barriers, including bureaucracy and emotional fatigue, while activists encountered resistance linked to systemic and institutional contexts. In contrast, restorers and observers reported fewer obstacles and were motivated by tangible outcomes or nature immersion. Activities involving public-facing or institutional coordination tend to be more demanding, while task-oriented roles offer more accessible pathways to participation.
These findings suggest that volunteer engagement and retention programs should be designed to attend to the specific characteristics and needs associated with different environmental volunteering activity types. Such a customized approach may be critical for strengthening the long-term resilience and effectiveness of environmental volunteering initiatives. More broadly, the study contributes to theory building in environmental volunteering research by supporting an activity-based perspective.
Supplementary material
The supplementary material for this article can be found at http://doi.org/10.1017/S0957876526000811.
Author contributions
Conceptualization: M.B.-A., J.C.M.S., E.P., P.V.-C., T.V.; Formal analysis: M.B.-A., J.C.M.S., E.P., P.V.-C., T.V.; Funding acquisition: M.B.-A.; Investigation: M.B.-A., J.C.M.S., E.P., P.V.-C., T.V.; Methodology: M.B.-A., J.C.M.S., E.P., P.V.-C., T.V.; Resources: M.B.-A.; Supervision: M.B.-A.; Writing—original draft preparation: M.B.-A.; Writing—review and editing: M.B.-A., J.C.M.S., P.V.-C., T.V.
Funding statement
The research leading to these results received funding from the Secretary of Open Government of the Ministry for Foreign Action and Open Government of the Government of Catalonia (Grant No. DEMOC00007).
Competing interests
The authors declare none.
Ethical standards
The research obtained the required ethics approval from the Research Ethics Committee (CER) of the Universitat Internacional de Catalunya.
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