Introduction

It is projected that by 2050, two-thirds of the world’s population will be living in cities (United Nations 2018). The phenomenon of rapid urban population increase is prevalent in the developing world, especially in Africa (COGTA 2016; OECD/UN ECA/AFDB 2022). Since 1990, the number of African cities increased from 3300 to 7600, and urban centres have added 500 million people (OECD/UN ECA/AFDB 2022). In South Africa, for instance, over 70% of the population will live in cities by 2030 (COGTA 2016). These rates of change place anthropogenic stresses on natural ecosystems in and around cities (Yussif et al. 2023). Multiple reasons have been offered to explain the rapid urbanisation in Africa, including people migrating from rural to urban centres in search of social services and economic opportunities, as well as proximity to administrative centres that are often situated in cities (Njoh 2003; Güneralp et al. 2017; Heinrigs 2020). As a result of the growing urbanisation and urban population, natural systems such as rivers and wetlands within cities have become seriously degraded (Uluocha and Okeke 2004; Walsh et al. 2005; Collier et al. 2015; Xu et al. 2019). Recent studies on the so-called urban river syndrome have shown that the hydrology, ecology, biodiversity, water quality and geomorphology of urban rivers have been severely altered due to pollution, land cover change, poorly designed and over-burdened sanitation services, run-off from roads and rail networks, industrial and domestic waste discharges (Capps et al. 2016; Jackson et al. 2016; Odume 2017). Systemic governance failure and urban poverty have also been identified as critical contributors to river ecological degradation in cities (Odume et al. 2022). As in many other parts of the world, the implications are that rivers in many cities in Africa have become seriously degraded, compromising their ecological function and the services they provide to society (Capps et al. 2016; Chen et al. 2022). In the Nelson Mandela Bay Metropolitan Area (NMBM) in the Eastern Cape of South Africa for example, rivers and streams within its urban landscape appeared to be seriously impacted (Odume 2017). This then raises an important but less researched question about how urbanisation re-configures relations between rivers and people, and how local urban populations perceive ecosystem services supplied by urban rivers in cities, as well as the factors that may mediate such perceptions.

The ecosystem services concept has largely been studied in rural contexts but not as much in urban landscapes, particularly aquatic ecosystems in Africa (Haase et al. 2012; Keeler et al. 2019). For this reason, the knowledge of how urban communities experience, perceive and value the services urban rivers provide remain sparse. It is thus important to assess local people’s perceptions and knowledge of ecosystem services in cities for several reasons. First, such an assessment has the potential to identify the ecosystem services that are most important to people (Martín-López et al. 2012; Hartel et al. 2014; Hossu et al. 2019). Second, it can reveal the ecosystem services that local people are most willing to conserve because of their perceived importance and value (Murata et al. 2019). Third, it can reveal important synergies and trade-offs that can occur when certain ecosystem services are consumed or conserved (Martin-Lopez et al. 2012; Hartel et al. 2014; Hossu et al. 2019). Fourth, the perception and knowledge of ecosystem services by urban communities can form the basis for mobilising individual, collective and relational agencies for positive actions given the urgent need to reverse the trajectory of ecological degradation of urban river systems (Everard and Moggridge 2012; Chen 2017; Odume et al. 2022) Fifth, such an assessment can inform the design and implementation of ecological interventions that are in line with local values (Harrison et al. 2010).

Therefore, the objectives of this paper are 1) to assess local communities’ perception and knowledge of different types of ecosystem services of an urban river in South Africa, 2) to assess the influence of particular demographic characteristics (age and gender), socio-economic characteristics (education, housing type, income, and years of residence), and prior knowledge of the ecosystem services concept influence people’s perception of the ecosystem services of the Swartkops River in the Eastern Cape of South Africa. This paper thus addresses two inter-related research questions: 1) how do people in an urban centre perceive river ecosystem services in an urban landscape? 2) how do selected demographic and socio-economic variables influence people’s perception of an urban river ecosystem services?

Materials and methods

The Swartkops River is located in the Eastern Cape Province of South Africa (Fig. 1). The river drains an urban catchment and then discharges into the Indian Ocean in Algoa Bay near the City of Port Elizabeth (Odume 2017). The water quality of the river is seriously impacted due to pollution and systemic governance challenges, threatening the sustainability of the ecosystem services provided by the river (Odume 2017; Adams et al. 2019; Odume et al. 2022).

Fig. 1
figure 1

Location of the Swartkops River in the Eastern Cape Province of South Africa

Full size image

Many communities within the Swartkops River catchment are impoverished, and this impoverishment is spatially distributed across the catchment (Odume et al. 2012). It has been reported that in the residential areas of Zwide to Uittenhage more than 60% of households depend on less than USD 300 per month as opposed to the City of Port Elizabeth area with higher household income (Nelson Mandela Bay Metropolitan Municipality 2022). Communities within the catchment utilise the river for fishing, bait collection, ancestral worshipping, church baptism, and swimming. The river also supports an important estuary, which the people rely on for recreational activities such as angling. It is thus an important river both ecologically and socio-economically.

Survey design and data collection

Questionnaires were used to assess perceptions of Ecosystem Services (ESs) of the Swartkops River. Survey data were collected from residents who were 18 years and older living within the river catchment. A team of ten trained field staff collected 181 surveys between May–June 2021. Ethical approval (Ethics Review No. 2019-0808-990) for the research project and data collection was obtained. The survey was conducted in English and orally translated into the local language isiXhosa, where necessary.

The survey contained a set of questions that asked about four different types of ecosystem services: provisioning (food, medicine, freshwater), regulating (flood reduction, regulation of local climate, waste transportation and purification), cultural (recreation, spiritual worship, cleansing and purification, aesthetic value) and supporting services (maintenance of species variety) (see Appendix 1) To assess local communities’ knowledge and perception of ecosystem services, respondents were asked to indicate if the river always, sometimes or never provides provisioning, regulating, cultural and supporting services. Respondent were also asked if they have had prior knowledge of ecosystem services. To assess the influence of demographic and socio-economic variables on the knowledge and perception of ecosystem services, respondents were asked about their age, sex, education, household income, housing type, years of residence near the river.

Data analysis

To understand perceptions of ecosystem services, we used a multinomial logit model to analyse people’s likelihood of indicating that the river “always”, “sometimes” or “never” provides a particular ecosystem service. These models are particularly useful for categorical data and in this study, provide an understanding of the likelihood that a respondent chooses a particular answer based on a set of characteristics. The characteristics tested in this model are described in Table 1 below.

Table 1 Biographic and socio-economic variables used in multinomial logit model estimation to understand respondents’ perceptions of ecosystem services in the Swartkops River system
Full size table

Models were estimated in Stata13.1 using the mlogit command and robust standard errors. The coefficients of the models are relative risk ratios which can be interpreted similar to an odds ratio. Relative risk ratios greater than one (1) indicate that a respondent is more likely to answer in a particular way, relative to a base category. For example, a relative risk ratio of 1.30 indicates a respondent is 30% more likely to respond in a particular way compared to respondents in the never category. A relative risk ratio less than one (1) indicates a respondent is less likely to answer in a particular way, relative to respondents in the base category of never.

Results

Demography and socio-economic profile of the respondents

The demographic and socio-economic profile of the respondents are provided in Appendix 2. Briefly, 60% of the respondent were male and 40% female. The age was almost equally split between people ages 18–34 years, 35 – 44 years and 45 and older. Many respondents completed only high school (42%), whereas 28% indicated that they had education beyond high school. Regarding other characteristics, the majority of respondents (66%) make between R2000 and R10 000 a month and 71% live in formal settlements with municipal services. Over 80% of respondents have lived near the river for over five years. This variable is important because it is related to experiential knowledge of the river and its characteristics. Fifty (50%) of the respondent indicated that they had prior knowledge of the concept of ecosystem services, the remaining 50% did not.

Knowledge and perception of ecosystem services

Figure 2 below indicates the perceptions of respondents regarding whether the river always, sometimes or never provides a particular ecosystem service. For the majority of the ecosystem services, there was almost an equal split between the perception “sometimes” and “never” that the river provides a particular service. For example, 48.07% of the respondents indicated that the river sometime provides recreational services, whereas 39.78% indicated that it never provides this service. In the same vein, 39.78% of the respondents indicated the river was never pleasing to look, the same percentage also indicated that the river was sometimes pleasing to look. A similar trend in responses was obtained for water transportation and purification services. The main exception to this trend is the regulation of local climate, for which many respondents (33.15%) indicated that the river always provide this services.

Fig. 2
figure 2

Perceptions of respondent regarding whether the river always, sometimes or never provides a particular ecosystem service

Full size image

Influence of demographic and socio-economic variables on the knowledge and perception of ecosystem services

We used multinomial logit models (Tables 2 and 3) to assess the influence of conceptual knowledge (i.e. prior knowledge of ecosystem services concept), experiential knowledge (years of residence) and their relationship with ecosystem services perception (Table 1), controlling for key.

Table 2 Summary of model results indicating the influence of conceptual (prior knowledge of ES), experiential (years of residence) knowledge and their interactions on ecosystem services perception
Full size table
Table 3 Summary of model results indicating the influence of genderm age, education, income and type of housing on ecosystem services perception in the Swartkops River
Full size table

demographic variables (age and gender), and socio-economic parameters (education, housing type, income. A review of the chi-square test statistic in Appendices 3–6 indicates that all of the models, with the exception of that for food were statistically significant at the 1% level. The model for food services was statistically significant at the 5% level. Models were not estimated for freshwater provision because nearly all respondents indicated the river never provides this service. Thus, there was not enough variability in the data to estimate multinomial logit models.

When both prior knowledge of ecosystem services and years of residence (Appendices 7–10) were included in the models, the chi-square statistics get larger and the statistical significance improves. All models, except the one for flood regulation are statistically significant at the 1% level. The model for flood regulation is significant at the 5% level. The pseudo R-squared values also increase and range in value from 0.18 for spiritual services to a high of 0.30 for water transportation and purification services.

Regarding the influence of conceptual and experiential knowledge on ecosystem services perceptions, experiential knowledge informed by people’s years of residence near the river was more important than conceptual knowledge for the provision of food services (Table 2 and Appendix 7). For surveyed respondents that indicated the river sometimes provides food services, conceptual knowledge of ES becomes insignificant when years of residence is included in the model. Only residents that have lived near the river between five and ten years were more likely to indicate that the river sometimes provides food services (Table 2). For the provision of medicine (Table 2 and Appendix 7), residents who lived near the river more than ten years were less likely to indicate that the river always provides medicine.

Regarding regulating services, conceptual knowledge of ES is relatively more important than experiential knowledge, as only people who indicated they had prior knowledge of the concept of ecosystem services were more likely to indicate that the river sometimes provide this service. In the models for flood regulation and the regulation of local climate (Table 2 and Appendix 8), conceptual knowledge of ES was statistically significant, even after including years of residence in the model, indicating its importance regarding the perception of this service. In the models for flood regulation, respondents with conceptual knowledge of ES were more likely to indicate the river always and sometimes provides flood regulation. In the models for regulation of local climate, both prior knowledge of ES and years of residence was important in explaining the responses of people who responded that the river sometimes regulates the local climate.

The model results for supporting services (Table 2 and Appendix 10) are similar to those for regulating services; prior knowledge of ES is more important than experiential knowledge of the river. For both species variety and water transportation and purification services, people were more likely to respond that the river always and sometimes provides these services if they had prior knowledge of the concept of ES (Table 2).

The results for cultural ES are more varied (Table 2 and Appendix 9). For recreation services, years of residence (i.e. experiential knowledge) rather than conceptual/prior knowledge of the concept of ES was more important to understanding the ‘always’ responses. People living near the river for more than five years were less likely to indicate that the river always provides recreation services. Conversely, prior knowledge of ES was more important to understanding the sometimes responses; people with prior knowledge of ES were more likely to indicate that the river sometimes provides recreational services.

For spiritual services, both conceptual and experiential knowledge of ES were important to explaining the always responses. Prior knowledge of the concept of ES made respondents more likely to indicate that the river always provides spiritual services. However, people living near the river for more than ten years were less likely to indicate that the river always provides spiritual services. Only years of residence was important in explaining the sometimes responses for spiritual services. People living near the river between five and ten years were more likely to indicate that the river sometimes provides this service.

For aesthetic services, conceptual knowledge of ecosystem services was more important in explaining the always responses; those with prior knowledge of the concept of ES were more likely to say the river always provides this service. Years of residence (i.e. experiential knowledge), however was more important to explaining the sometimes responses. People living near the river between five and ten years were more likely to indicate the river sometimes provides aesthetic services.

In addition to conceptual and experiential knowledge as key variables influencing local people’s perception of ecosystem services, we also assessed other variables as shown in Table 3. Gender was particularly important for the food and aesthetics models; men were more likely than women to indicate that the river always provides food and aesthetic services. They were also more likely to indicate that the river sometimes provides spiritual services.

In terms of age, the results are mixed across age groups and for different types of ecosystem services. For example, respondents between the ages of 35–44 were more likely to state that the river always and sometimes provides species variety (Table 3 and Appendix 10). They were also more likely to state that the river sometimes provides recreational services (Table 3 and Appendix 9). Older respondents however were less likely to indicate the river sometimes helps to regulate the local climate (Table 3 and Appendix 8) and provides spiritual services (Table 3 and Appendix 9). They were more likely to indicate however that the river sometimes provides species variety (Table 3 and Appendix 10).

Education was not individually significant in most of the models, except for the model for water transportation and purification services (Table 3 and Appendix 10). Here, residents with a high school certificate were less likely to indicate the river always provides this service. Income was individually significant in many of the models where people indicated the river sometimes provides a particular service. In these instances, upper-middle income survey respondents with monthly incomes between R5,000-R10,000 were more likely to say that the river sometimes provides recreational services (Table 3 and Appendix 9) and species variety (Table 3 and Appendix 10). The highest income survey respondents with monthly income greater than R10,000 were more likely to say that the river sometimes regulates local climate (Table 3 and Appendix 8) and sometimes provides species variety (Table 3 and Appendix 10). They were less likely to indicate that the river provides aesthetic services however (Table 3 and Appendix 9).

Lastly, type of housing was individually significant in several of the models. Residents in formal housing with municipal services were less likely to indicate the river always provides species variety (Table 3 and Appendix 10). Residents living in both informal and formal housing with municipal services were also less likely to indicate the river always provides water transportation and purification services (Appendix 10). The same was true for local climate regulation (Table 3 and Appendix 8) and species variety (Table 3 and Appendix 10); residents in housing with municipal services were less likely to say the river sometimes regulates the local climate and sometimes provides species variety. Residents of informal housing with municipal services were less likely to say the river provides aesthetic services (Table 3 and Appendix 9).

Discussion

The goal of this paper was to assess local people’s perceptions and knowledge of ecosystem services supplied by rivers in urban centres. We also assessed factors that may mediate local people’s perceptions of ecosystem services. The survey results indicated variation in the extent people felt the river provided a variety of services. For many services, people were more likely to indicate the river sometimes or never provided a service instead of always. One service however, for which there was almost universal agreement was the provision of freshwater; most respondents indicated the river never provided this service. This is likely because of high levels of pollution of the river. The Swartkops River is regarded as one of the most polluted river systems in the Eastern Cape of South Africa (Tshithukhe et al. 2021). High levels of E. coli, pharmaceutical compounds, metals and other chemical pollutants have previously been reported (Odume et al. 2012; Farounbi and Ngqwala 2020; Vumazonke et al. 2020; Ohoro et al. 2021). It is possible that residents’ familiarity with, and experiential knowledge of the river water quality may have shaped the perception that the river never provided freshwater. Another possibility could be the level of water service delivery within the catchment. Nearly 100% of households had access to piped municipal water, minimising their reliance on the river for drinking water (Nelson Mandela Bay Metropolitan Municipality 2022). In addition to pollution, other factors such as habitat degradation, seasonality, and overall catchment health may mediate when and how a river, particularly one situated in a human-dominated catchment, provide ecosystem services (Petsch et al. 2023).

Overall, our results highlight the importance of knowledge of the local environment (Moutouama et al. 2019), socio-economic status, and access to municipal services as key factors that shape people’s perceptions of ecosystem services. Gender, age, income and housing types were important variables that influenced people’s perception of ES provided by the Swartkops River. For example, men were more likely than women to indicate that the river always provides food and aesthetic services. They were also more likely to indicate that the river sometimes provides spiritual services. Fishing and bait collection are common in the Swartkops River, and angling is common on the estuarine portion, and these are mainly done by men (Odume et al. 2012). This may explain why men were more likely to indicate that the river provides food and aesthetic services than women. Regarding incomes, it appears that respondents in the higher income bracket tend to show more appreciation for the intangible services such as species diversity and regulation of climate. It is well-established that reliance on local material ecosystem services tend to decrease as household income improves (Cortés-Espino et al. 2023), however, what our results seems to suggest is that appreciation for the intangible services seems to increase with increasing household income.

While some of the demographic and socio-economic characteristics discussed above are known sources of variation in ES perception (e.g. Atchadé et al. 2023), the most novel finding of the present study was related to differences in perceptions of urban river ES arising from conceptual knowledge compared to experiential knowledge. For provisioning services (e.g. food) and cultural services, experiential knowledge significantly influenced how people perceive these ecosystem services, whereas for many of the intangible services such a regulating local climate and species diversity, conceptual knowledge significantly influenced how people perceive these services. Therefore, it seems that experiential knowledge plays a key mediating role for ecosystem services that have direct use value (e.g. food and recreation), but less so for services that are of no direct or immediate use value. These results support prior work noting people tend to have more knowledge of and assign higher value to ecosystem services that have direct use value (Murata et al. 2019; Lewan and Söderqvist 2002).

Rivers provide important regulatory and supporting services such as flood control, local climate regulation, erosion prevention and population and habitat maintenance (Kaiser et al. 2020). For the most part, these regulatory services do not have direct use value. The results indicate that conceptual knowledge of ES were comparatively more important than experiential knowledge for this type of ES. People who had prior knowledge of the concept of ecosystem services were more likely to indicate that the river sometimes or always provided these regulatory services.

Model results for cultural services suggested mixed importance of both conceptual and practical knowledge of ES. For the most part, cultural services such as recreation can be perceived as having direct use value, hence the importance of experiential knowledge, but services such as sense of identity may not, hence the relevance of conceptual knowledge. In the present study, there was a split in responses between sometimes and never for cultural services such as recreation and aesthetic. The research participants were of the view that the river does not always provide these services. As already indicated, the Swartkops River is seriously polluted, although the level of pollution is seasonally mediated (Farounbi and Ngqwala 2020; Vumazonke et al. 2020). The awareness of the river pollution among the respondents may have contributed to the responses, as residents may be aware of the risk posed in using polluted water for recreational purposes.

Overall, the findings related to different types of knowledge and perceptions of ES imply that raising awareness and education among locals may contribute to a better appreciation of the diversity of services urban rivers provide, beyond those with direct use value. This suggestion is supported by Zedda (2023), who has also stressed the importance of education and awareness raising as a way of deepening the concept of ES in society. Here, it is important to note that education and awareness raising should not assume that highly educated people or decision makers are aware of ES. In fact, prior work involving a diverse set of participants including politicians, government officials and researchers, found that participants showed little understanding of ecosystem services (Lewan and Söderqvist 2002). Therefore, education and awareness efforts should be tailored to a diverse range of stakeholders with varying education levels, including those with formal education and higher degrees.

Although our study provided new insights about human-river relationality in an urban context, it is important to note some of the limitations, which are based on a case study of one urban river at one point in time. Study results obtained in the future may differ from the ones presented here due to differences in river condition at the time of follow on studies or a different sample of participants, whose views about the river could differ from the sample of people profiled in the present study. These limitations suggest two avenues for future research. One avenue is the extension of the current study framework to other urban rivers. A second extension is to examine the linkages between urban river pollution and the perception of ecosystem services. Water quality is an important factor that affects what the water in a river can be used for. For this reason, we assume that it could be an important factor that could influence how people perceive not just the river, but the services that flow from it. It will therefore be interesting to empirically examine the relationship between perception of ecosystem services and water quality in a future study.

An understanding of ecosystem services may impact how people interact with urban rivers, but little is known about perceptions of urban river services on the African continent, and in South Africa in particular. To fill this knowledge gap, this paper analysed residents’ perceptions of urban river services provided by the Swartkops River in the Eastern Cape of South Africa. The results of this examination suggest a linkage between demographic and socio-economic variables and people’s perceptions of a variety of ecosystem services. The key implication flowing from the study is there is a need for innovative ways to strengthen people-river relations so that people value river systems more highly and take proactive measures to protect these important ecosystems.