Co-production of nature’s contributions to people in dry rivers: a case study in Murcia, Spain

ABSTRACT

Dry rivers are non-perennial rivers with no surface water in their channels except after heavy rainfall or snowmelt. The lack of water flow is often associated with a low provision of Nature’s Contributions to People (NCP) and a poor quality of life. However, recent review studies have found evidence of human communities thriving in dry rivers through the co-production of multiple NCP, although no case studies have yet confirmed this evidence. We assessed the capacity of dry rivers and their associated social systems to provide NCP. We selected three dry rivers with high natural, cultural and landscape values in the most arid part of Murcia (Spain). We interviewed 37 representatives of the most influential social groups in the study area to explore the NCP of dry rivers, their synergies and trade-offs. Four material, three non-material and eight regulating NCP were identified, as well as one unique NCP: access to villages and fields through dry riverbeds. Fifty-two synergies were identified, especially between material and non-material NCP, and eight trade-offs. This wide range of NCP and synergies is a consequence of the co-production processes between dry rivers and the social system. NCP co-production seems to be underpinned by the indigenous and local knowledge acquired by the social system over generations about the management of floodwaters, biodiversity and geodiversity. Incorporating this knowledge into research and governance can help raise awareness of the NCP provided by dry rivers and help develop strategies for mitigating and adapting to global change.

Key policy highlights

• Dry rivers provide benefits that contribute to people’s quality of life. These benefits are co-produced by dry rivers and their associated social systems. The co-production of benefits depends on the traditional knowledge that social systems have acquired over generations.

• The co-production of benefits between dry rivers and their social systems is a sustainable reference model, providing food, freshwater, medicines, building materials, natural habitats, soil protection, scientific advances, recreation and cultural identity.

• Benefit co-production and traditional knowledge from dry rivers not only contribute to people’s quality of life, but are also a source of strategies for coping with global change, particularly climate change in drylands.

• Society seems to be unaware of the high value of dry rivers for our quality of life. Integrating benefit co-production and traditional knowledge into governance is essential to revalue these ecosystems and develop effective management policies.

EDITED BY:

• Ágnes Balázsi

KEYWORDS:

• Temporary rivers
• ephemeral streams
• ecosystem services
• open-ended interviews
• synergies
• indigenous and local knowledge

1. Introduction

Rivers are valued by society when they provide benefits to people (e.g. food, freshwater, fertile soil, recreation) and contribute to human well-being (Vidal-Abarca and Suárez 2013; Yeakley et al. 2016; Hanna et al. 2017; Sosa et al. 2018; Grizzetti et al. 2019; Hale et al. 2019; Thiele et al. 2020; Watz et al. 2021). However, not all types of rivers are valued in the same way because their capacity to provide benefits is perceived by society differently depending on their water flow regime (Eder and Arnberger 2016; Koundouri et al. 2017; Leigh et al. 2019). Perennial rivers, those that constantly flow through time and space, are highly valued as they are associated with a large provision of benefits. In contrast, non-perennial rivers, those that intermittently flow through time and space, are less valued as they are associated with a limited provision of benefits (Armstrong et al. 2012; García-Llorente et al. 2012; Garzón et al. 2013; Armstrong and Stedman 2020; Magand et al. 2020; Rodríguez-Lozano et al. 2020; Jorda-Capdevila et al. 2021).

Dry rivers are a type of non-perennial river and can be found in all climates, especially in arid and semi-arid regions (Messager et al. 2021; Nicolás-Ruiz et al. 2021). Their channels remain dry for most of the hydrological cycle, are disconnected from groundwater and do not harbour aquatic life (Vidal-Abarca et al. 2020). Occasionally, heavy rainfall or snowmelt events can disrupt the dry condition causing flash floods, which play a fundamental role in shaping the dry river morphology. Since the absence of surface flow is the usual condition of these rivers, the perception of their capacity to provide benefits is extremely low. As a result, dry rivers are highly undervalued by society (García-Llorente et al. 2012; Vidal-Abarca et al. 2020) lacking of proper management (Larned et al. 2010; Acuña et al. 2014; Biggs et al. 2016; Fritz et al. 2017; Skoulikidis et al. 2017; Stubbington et al. 2018) and conservation plans (Armstrong et al. 2012; Rodríguez-Lozano et al. 2020). The geomorphology and biodiversity of dry rivers are often altered by human activities, known as drivers (Díaz et al. 2015). For example, processes of urbanisation and intensification of agriculture, rubbish and effluent dumping, and overexploitation of aquifers are among the most important drivers (Ballester et al. 2003; Gómez et al. 2005; Di Baldassarre et al. 2010; Chiu et al. 2017; Sánchez and Toro 2020; Vidal-Abarca et al. 2020, 2022).

While only a dozen studies addressed the benefits of dry rivers until 2010, the number of publications has increased eightfold over the last decade (Nicolás-Ruiz et al. 2021). Early publications revealed that while dry rivers provide benefits such as food, vegetable fibres, medicinal plants, climate regulation and recreational places (Levick et al. 2008; Larned et al. 2010; Armstrong et al. 2012; Steward et al. 2012; Acuña et al. 2014; Boulton 2014; Datry et al. 2014; Leigh et al. 2015), most of them are altered by the absence of water flow (Datry et al. 2017; Koundouri et al. 2017). Based on these results and the pejorative social perception, it could be assumed that the capacity of dry rivers to provide benefits is low compared to perennial rivers.

However, recent studies have questioned this approach on two grounds. Firstly, the benefits of dry rivers may be underestimated as most studies approach their assessment from an aquatic perspective, ignoring that dry rivers mainly support a terrestrial environment throughout the hydrological cycle (Arce et al. 2019; Vidal-Abarca et al. 2020; Nicolás-Ruiz et al. 2021). For example, although dry rivers do not provide fishing, they do support hunting, and despite dry rivers not supporting water sports, they do allow land sports such as mountain biking (Vidal-Abarca et al. 2020). Secondly, review studies have found evidence of human communities thriving around dry rivers in arid and semi-arid regions around the world (Vidal-Abarca et al. 2020, 2022). For example, one-fifth of Namibia’s population living near dry rivers may benefit from their wetter and more fertile land to grow crops and collect water and medicinal plants (Jacobson et al. 1995). Considering these evidences, dry rivers could be posed as ecosystems providing as much diversity of benefits to people as perennial rivers. However, no case study has yet tested whether a single dry river could deliver a wide range of benefits.

The conceptual framework developed by the Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES) depicts the relationships that operate between natural and social systems. According to this framework, not only natural systems are involved in providing benefits to people, but social systems also play an important role (Díaz et al. 2015; Pascual et al. 2017). This process is sometimes referred to as benefit co-production (Comberti et al. 2015; Palomo et al. 2016; Bruley et al. 2021). The social system can intervene in co-production in two ways, physically and cognitively (Palomo et al. 2016). For example, the success of cultivation in semi-arid basins depends not only on the fertility of the floodplains (natural system), but also on the construction of crop terraces by social system to prevent erosion and to regulate freshwater loss (Iniesta-Arandia et al. 2014). Otherwise, inspiration for art is a benefit provided by natural elements (e.g. species, landscapes), included dry rivers, and human cognitive processes (e.g. emotions) (Palomo et al. 2016). Benefit co-production is often underpinned by a set of traditional knowledge and practices about nature-human relationships that are transmitted between generations, referred to in the IPBES framework as indigenous and local knowledge (Díaz et al. 2015; Pascual et al. 2017).

Social perceptions of which elements of nature are beneficial or detrimental to human well-being vary according to the culture and values of different societies and individuals (Díaz et al. 2015). To encompass these different perceptions, the IPBES framework adopted the terms Nature’s Contributions to People (NCP) and good quality of life (Díaz et al. 2018). NCP include concepts such as ecosystem services or nature’s gifts (beneficial NCP) and disservices (detrimental NCP) (Díaz et al. 2015; Shackleton et al. 2016). Good quality of life refers to concepts related to human well-being and living in harmony with nature (Brondízio et al. 2019). This paper focuses only on the beneficial NCP of dry rivers to a good quality of life. The IPBES framework proposes two perspectives for analysing NCP: a generalising perspective and a context-specific perspective (Díaz et al. 2018). The former, typical of Western science, distinguishes three NCP groups: material (support people’s physical existence), no-material (support people’s psychological existence) and regulating NCP (i.e. regulate the environmental conditions that make human life possible). The latter, typical of indigenous cultures, corresponds to other worldviews whose NCP groups depend on their own cultural context.

NCP are not independent of each other, but are part of a complex web of synergies and trade-offs between them (Bennett et al. 2009). In a synergy, two NCP may increase either by their own interaction or due to a simultaneous response to a driver (Bennett et al. 2009). Synergies increase when the social system is committed to sustainable NCP co-production (Quintas-Soriano et al. 2022). For example, farming terraces increase food production, but also regulate freshwater and soil erosion (Guo et al. 2021). In a trade-off, one NCP increases while another decreases by their own interaction or due to a simultaneous response to a driver (Bennett et al. 2009). Trade-offs occur when the social system focuses on promoting one NCP at the expense of others (Rodríguez et al. 2006). For example, agricultural intensification increases food production, but reduces water quality (García-Llorente et al. 2015). We hypothesise that, given the arid climate of dry rivers, their capacity to provide NCP will be highly dependent on the co-production processes between natural and social systems, which promote synergies between NCP.

The purpose of this paper is to assess the capacity of dry rivers to provide NCP. To achieve this, two specific objectives were established: i) to analyse the processes of NCP co-production between dry rivers (natural system) and their associated human communities (social system) and ii) to determine how NCP co-production influences the development of synergies and trade-offs.

2. Case study

The study area is located in the municipalities of Cartagena and Mazarrón, in the Region of Murcia in south-eastern Spain, and comprises three small basins that flow into the Mediterranean Sea: Valdelentisco (22.62 km²), El Cañar (22.96 km²), and La Azohía, (13.29 km²) (Figure 1). The climate is hot semi-arid with an average annual temperature of over 18°C (Garrido et al. 2014). The average annual rainfall ranges from 300 mm in the upper parts of the basins to 150 mm in the lower parts (DGMN 2006). The maximum altitude is 625 m at the peak of Peñas Blancas.

Figure 1. Location of the region of Murcia in south-eastern Spain and map of the study area. The black line delimits the study basins: Valdelentisco, El Cañar and La Azohía. The thick blue lines are the dry rivers and the thin blue lines are their tributaries. The triangles are the highest mountain peaks. The blue cross is a small flood-dependent spring. The red circles are the villages. The grey rectangles are urban areas. Terrestrial and marine protected areas are represented with different symbols. PNA = protected natural area; SPA = special protection area; SCI = site of community importance; SAC = special area of conservation; CRS = coordinate reference system.

The mountainous areas are covered by scrub (e.g. Rhamnus lycioides, Chamaerops humilis) and herbaceous species (e.g. Stipa tenacissima), sometimes interrupted by small patches of tree vegetation (e.g. Pinus halepensis, Quercus rotundifolia). Dry rivers support herbaceous (e.g. Arundo donax), scrub (e.g. Nerium oleander, Myrtus communis) and tree species (e.g. Tamarix canariensis, Populus alba) with higher water requirements. These habitats host more than a hundred species of birds (e.g. Sylvia melanocephala, Galerida theklae), and dozens of small mammals (e.g. Vulpes vulpes, Genetta genetta) and reptiles (e.g. Podarcis hispanica, Lacerta lepida), some of them currently protected (e.g. Testudo graeca, Hieraaetus fasciatus) (DGMN 2006).

The population in 2021 was 1689 inhabitants, of which 37% were foreigners (AdC 2021). The population was aging as a result of the rural exodus of young people and the low birth rate (DGMN 2006). In the upper parts of the basins there are three small villages and scattered hamlets (Figure 1) where 7% of the population resides. Traditionally they have been engaged in agriculture, herding, hunting and handicrafts. In the lower part there are six urban areas where 93% of the population resides. It is a traditional fishing area and more recently a tourist place with some crop greenhouses. All villages and urban areas are governed by two neighbourhood councils, local decision-making bodies with a political character that depend on the municipal government.

One third of the study area is protected at the European level by Natura 2000 Network (DGMN 2018a, 2018b) and at the regional level as a Protected Natural Area (DGMN 2006). The former aims to conserve biodiversity and natural habitats, while the latter aims to conserve traditional human activities (Figure 1). The marine environment is protected at the European level by the Natura 2000 Network and at the regional level as a fishery reserve (BORM 2016). The former aims to conserve the habitats of Mediterranean islets (DGMN 2020a), submerged coastlines (DGMN 2020b) and underwater valleys (DGSCM 2016), while the latter aims to conserve fishery resources. The conservation of the terrestrial environment, as well as the marine environment given that rivers support coastal habitats of human interest (Santos-Martín et al. 2015), suggests that dry rivers in the study area could provide multiple NCP.

3. Material and methods

3.1. Sampling and interview design

We interviewed 37 representatives from 10 of the most influential social groups in the study area: crop farmers (4), environmental managers (5), neighbours (7), hunters (2), researchers (4), tourism sector (3), livestock farmers (2), non-profit organisations (6), fishermen (2) and neighbourhood councils (2) (Supplementary material S1A). The social groups were selected on the basis of their main socio-economic (e.g. agriculture, livestock) or socio-cultural activities (e.g. hiking, pilgrimages) in the dry rivers. They were identified prior to the interviews through local literature and field trips to the study area. The interview candidates with the most experience and knowledge (formal and informal) of dry rivers were selected to represent the social groups. All representatives were considered as local people, regardless of their place of birth or country of origin, as they carry out their occupational activities in the study area. To recruit them, we conducted a snowball sampling, which consists of asking representatives to introduce the researcher to others who meet the criteria for inclusion in the study (Kirchherr and Charles 2018; Knott et al. 2022). We interviewed at least two representatives of each social group because of the small population size and the interviewees’ wide knowledge of activities in the area. These criteria are consistent with the objective of exploring the NCP of dry rivers.

We asked interviewees for their social data (gender, age, education and basin where they operate) before starting the interview to ensure that we included as diverse a range of interviewees as possible (S1B). Women (n = 9) were less represented than men (n = 28) due to the dominant position of men in agriculture, pastoralism, fishing and hunting, as well as in senior positions in environmental management bodies, academia, non-profit organisations and the tourism sector. The age of the interviewees ranged from 28 to 86 years, with an average age of 56.

We designed a semi-structured interview, which was organised around a topic guide linked to the study objectives. Each topic included a set of questions adaptable to the context of each interviewee. We used open-ended questions because, unlike closed questions, they elicit more elaborate answers and contextual reflections (Knott et al. 2022). The open-ended questions were tested with participants who were active in the dry rivers during previous visits to the study area (e.g. goatherds, hikers). This interview method has been successfully applied in many studies of NCP (Asah et al. 2014; Klain et al. 2014; Gould et al. 2015; Cheng et al. 2019; Topp et al. 2020). The first topic focused on the NCP co-production (objective i) through the questions: What benefits do dry rivers provide to you? What activities do you do in dry rivers? What do you use dry rivers for? The second topic focused on synergies and trade-offs (objective ii) through the questions: Do you collaborate with other social groups to develop your activity? Do you think your activity benefits or harms other activities? Are there conflicts between social groups over the use of dry rivers?

Interviews were conducted from December 2019 to March 2020. Snowball sampling started with representatives from the two neighbourhood councils, who provided information on other social groups. All representatives of social groups were first contacted by phone or email to introduce the project, the relevance of citizen participation and to request their collaboration through a face-to-face interview. All of them gave their consent to be interviewed by means of a consent form, which informed them about the dynamics of the interview, data protection, audio recording, taking photographs and means of contact. Their anonymity was preserved during all phases of the research. The interviews were conducted using a voice recorder and were limited to approximately 30–60 minutes.

3.2. Data processing and analysis

The information collected from the interviews was processed with MAXQDA Analytics Pro 2020, a software specialised in the analysis of qualitative data (Rädiker and Kuckartz 2019, 2020). The audio files of the interviews were imported into the software and manually transcribed into text. The NCP of dry rivers, their synergies and trade-offs were identified through the comprehensive reading of the interviews. We considered any beneficial contribution of dry rivers to the quality of life of the interviewees to be an NCP (Díaz et al. 2015). We considered a synergy when an NCP A either supported or enhanced an NCP B, and a trade-off when an NCP A was detrimental to an NCP B.

The NCP were classified into categories through a coding process (Knott et al. 2022). We applied the generalising perspective of the IPBES conceptual framework, which distinguishes 18 NCP categories grouped into three clusters: regulating, material and non-material NCP (Díaz et al. 2018) (S2). The NCP of dry rivers that could not be attributed to any category of the IPBES framework were grouped separately. We assigned each interview as many codes as NCP categories were identified in it. Each identified synergy or trade-off was assigned by two codes corresponding to the two involved NCP categories.

The coded NCP categories were qualitatively described by synthesising the perceptions reported by the interviewees. The description focused on both the elements of the natural system (e.g. animals, plants, rocks) and the inputs of the social system (e.g. plantations, water harvesting systems) that are jointly involved in the NCP co-production. All NCP categories were exemplified by verbatim quotes from the interviewees. We created a frequency table to count the number of interviewees (Ni) and social groups (Ng) that reported each NCP category. These two indicators provided an exploratory view of the most noticeable NCP categories for the social system. This is an approximation that needs to be corroborated with larger population samples to reach solid conclusions.

The coded synergies and trade-offs between the NCP of dry rivers were described qualitatively. The description involved the pairs of NCP categories gave rise to synergies and trade-offs, and examples based on the verbatim quotes from the interviewees. We counted the number of interviewees (Ni) and social groups (Ng) that reported each synergy and trade-off in order to explore which of them were most noticeable for the social system. This is an approximation that needs to be corroborated with larger population samples to reach solid conclusions. For both qualitative and quantitative analysis, a code co-occurrence function was applied to the coded interviews with MAXQDA. This function returns a pairwise matrix where each element represented the number of interviewees (Ni) or social groups (Ng) who reported a synergy or trade-off between two NCP categories (S3A). The pairwise matrix results were plotted using the MAXMaps tool (Kuckartz and Rädiker 2019).

4. Results

4.1. Nature’s contributions to people provided by dry rivers

We identified 16 NCP categories provided by dry rivers: eight regulating, four material, three non-material, and the NCP category of maintenance of options (Figure 2). Material NCP were the most reported by interviewees (Ni = 37), followed by non-material (Ni = 36), regulating (Ni = 30) and maintenance of options (Ni = 2). In addition, most interviewees reported an NCP not attributable to any of the categories of the IPBES framework (Ni = 22): the use of dry riverbeds to access villages and fields.

Figure 2. Nature’s contributions to people (NCP) provided by dry rivers as reported by interviewees. NCP are classified according to the categories proposed by the generalising perspective of the IPBES conceptual framework. A category of NCP not included in the previous framework is also applied: access to villages and fields. The number of interviewees that reported each NCP category is indicated.

4.1.1. Material NCP

Food and feed was the most reported material NCP (Ni = 37; Figure 2; Table 1). The inhabitants explained that they have always lived solely on crops and animals supported by the dry rivers. Rainfed farmers often emphasised crop diversity present in the dry riverbanks: nuts (e.g. almond, pistachio), cereals (e.g. barley, oat), legumes (e.g. pea), fruit trees (e.g. carob, date). Most of the families have small allotments (e.g. potato, carrot) and orchards (e.g. orange, plum), wild edible plants (e.g. asparagus), beehives for honey production, and some farm animals (e.g. goat, pig, chicken) for their own consumption:

‘El Cañar allowed all the families to live without having to work, and we lived well, both those who had more and those who had less […] My father ran my grandfather’s farm, which allowed us and my grandparents to live.’ (1_CRO_T3)

Table 1. Material nature’s contributions to people (NCP) provided by dry rivers, as reported by interviewees. Material NCP are classified by applying the categories proposed by the generalising perspective of the intergovernmental science-policy platform on biodiversity and ecosystem services (IPBES) conceptual framework (Díaz et al. 2018). The number of interviewees (Ni) and social groups (Ng) reporting each NCP category are indicated. The NCP categories are exemplified by verbatim quotes from the interviewees.

NCP category	Ni	Ng	Examples (verbatim quotes)	Interviewee
Food and feed	37	10	‘Fifty years ago, the people who lived there subsisted on rainfed crops, if there was a spring or a dry river with waterwheels for irrigation’	2_MAN_L2
			‘There used to be a lot of carob trees for animal feed. Now it is marketed and I have declared the farm as organic. I produce carob and I am in a cooperative, apart from selling to individuals’	1_CRO_T3
			‘There are a few herders left. In La Plata there is a big one, and in El Cañar there is another goat herder and his son who make their own cheese with a designation of origin. There are few resources, but enough to live on’	3_NEI_R2
Materials, companionship and labour	26	9	‘Esparto grass was used for everything as plastic didn’t exist. It was used to make baskets by means of pleita*, mats for the feet, blowers for stoking the fire, esparteñas**’	1_CRO_T1
			‘In the old days, they had donkeys because you had to prepare and plough your land’	8_ORG_S2
			‘Before, there were no roads, there was a path and we did everything with the animals we had. In my house, we had two donkeys with packsaddle and aguaderas***’	1_CRO_T3
Medicinal and genetic resources	12	8	‘The herb that grows in the dry river has been used for kidney problems’	5_RES_3
			‘There is a sterile cellulose membrane separating each node of Arundo donax and it was used as a dressing to cut bleeding from small wounds’	5_RES_3
			‘In the past, medicine was natural, spider webs were used for cuts and wounds’ ‘In all dry rivers there are older people with traditional knowledge about medicinal plants that we appreciate but unfortunately it is being lost’	1_CRO_T1 3_NEI_B2
Energy	10	6	‘When I was ten years old, I used to cut brushwood and load it on the beasts. Then the load was transported to the quarries, where brushwood was used to burn the gypsum’	1_CRO_T3
			‘There are mountain goatherds who cook with brushwood. Something as rural as this is unique in the Mediterranean’	6_TOU_2
			‘One of the only two water flour mills on the coast of the Region of Murcia is in El Cañar dry river, which is in ruins’	8_ORG_E2

CRO_T: traditional crop farmer, MAN_L: land environmental manager, NEI_B: basin-born neighbour, NEI_R: region-born neighbour, RES: researcher, TOU: tourism sector, ORG_E: environmental non-profit organisation, ORG_S: social non-profit organisation; *esparto band made up of seven to twenty-one plaited strands; **shoes made of esparto; ***baskets made of esparto that are placed on the back of an animal to carry and protect water jugs.

Fishermen described La Azohía as a traditional fishing village, where shellfish (e.g. sea urchins, clams, octopus) and fishes (e.g. anchovies, groupers, gilt-head breams) are caught in the vicinity of the dry river month. A valued traditional fishing gear is the Almadraba, a maze of nets fixed near a coastal bend that takes advantage of tuna migration between the Atlantic Ocean and the Mediterranean Sea.

Shepherds also contribute lamb, milk and cheese. They graze sheep and goats along dry rivers, where they feed on shoots and roots, and provide them with feed made from non-commercial dried fish and carob. Hunters are involved in the feeding of hunting prey (e.g. partridges, rabbits):

‘Hunting grounds and forests are sown for animals, roads are repaired, feeding and drinking troughs are installed, and hunting prey are restocked in accordance with the law.’ (4_HUN_2)

Materials, companionship and labour was the second most reported material NCP (Ni = 26; Figure 2; Table 1). Inhabitants use vegetable fibres from riverbanks (e.g. Stipa tenacissima, Chamaerops humilis, Arundo donax, Agave americana, mosses) to make household utensils (e.g. brooms, baskets, mats, bellows), clothing (e.g. esparto shoes or esparteñas), fishing equipment (e.g. ropes), farming equipment (stakes for training crops), roofs and sheds (e.g. beams), and decoration (e.g. crafts, handmade nativity scene):

‘All women gathered in the evenings to make “filete” [esparto rope made up of two plaited strands] while chatting, they were called “candangas” [meeting]. The “filete” would be bartered with “recoveros” [traditional street vendors].’ (8_ORG_S2)

Dry river sediments such as rocks, stones, gravels, sands and clays were used for building pedrizas (stone terraces for cultivation), aljibes (traditional water storage cisterns), wells, threshing floors and traditional houses, and for drying esparto grass to make it more resistant and fish to make fodder. Animal fur was used to make clothing (e.g. rabbit fur for gloves). At the basin level, there were also deposits of gypsum and láguena (impermeable slate soil) used for construction, and iron mines.

Farmers and neighbours pointed out the role of labour animals (e.g. donkey, mule, guard dog) in facilitating farming activities (e.g. ploughing, sowing, reaping, threshing), material transport (e.g. vegetable fibres, freshwater, cereals), well water extraction (e.g. donkey-drawn waterwheels), and guarding livestock, but they also valued their companion:

‘Sometimes I would fall asleep on the threshing floor. Then the mule would always stop, she would never pass over you. What a wonderful animal she was!’ (1_CRO_T2)

Medicinal and genetic resources such as aromatic plants used in traditional cooking (e.g. Foeniculum vulgare, Satureja obovate) and herbal medicines (e.g. thyme for herbal teas) were described by interviewees (Ni = 12; Figure 2; Table 1), who noted that they are now most commonly used by elder people and healers. Some farmed animals (e.g. Murciano lamb, Segureño lamb), cultivated varieties (e.g. fig trees, date palms), and hunting prey (e.g. wild partridge) are highly appreciated to locals because of their food quality:

‘This area is extraordinary for small game hunting because there are no pine trees and the native partridge is very good.’ (4_HUN_2)

Today, part of the basin, especially the coastal area, is supplied with electrical energy, but eldest locals recall how half a century ago they relied almost exclusively on brushwood (e.g. Anthyllis cytisoides, Thymelaea hirsuta, Calicotome intermedia) for cooking, baking bread and smelting gypsum (Ni = 10; Figure 2; Table 1). They also used solar energy to dry fish and esparto grass, and wind and hydraulic energy by means of flour mills. The Cañar watermill was powered by a waterfall whose flow came from a pond that collected spring, ground and flood water through traditional ditches.

4.1.2. Non-material NCP

Physical and psychological experiences was the most reported non-material NCP (Ni = 36; Figure 2; Table 2). Hiking was described by 65% of the interviewees as the most popular recreational activity for locals and tourists, often linked to the aesthetic, olfactory and auditory enjoyment of plants, animals, and socio-cultural landscapes:

‘“I like to walk along the dry river because you see lavender, rosemary, thyme, the smell they give off. If you leave the dry river all that doesn’t exist” (8_ORG_S2); “It is a pleasure to see some predators. I have fun watching the owls and eagles.”’ (4_HUN_2)

Table 2. Non-material nature’s contributions to people (NCP) provided by dry rivers, as reported by interviewees. Non-material NCP are classified by applying the categories proposed by the generalising perspective of the intergovernmental science-policy platform on biodiversity and ecosystem services (IPBES) conceptual framework (Díaz et al. 2018). The number of interviewees (Ni) and social groups (Ng) reporting each NCP category are indicated. The NCP categories are exemplified by verbatim quotes from the interviewees.

NCP category	Ni	Ng	Examples (verbatim quotes)	Interviewee
Physical and psychological experiences	36	10	‘There is daily hiking along La Azohía dry river, no less than 50 people, and some days even a few hundred, and European groups who organise themselves’	8_ORG_E1
			‘Yesterday we removed the vine shoots. At weekends my son usually comes to prune them and he says it clears his mind’	1_CRO_T2
			‘El Cañar dry river and its pilgrimage are lovely, especially if you go with your partner and children for a picnic. It’s very quiet’	9_FIS_2
Learning and inspiration	34	10	‘There was a livelihood because after several generations your grandfather would say plant a fig tree and we will have figs, four olive trees, four almond trees, four carob trees, and reeds [Arundo donax] for the house’	6_TOU_2
			‘I paint these desert areas a lot. My work and my inspiration revolve around desert areas, iron oxide, mines, slate’	3_NEI_R2
			‘El Campillo de Adentro is a very beautiful area to behold, my wife painted an oil painting because it was full of chrysanthemums in bloom’	5_RES_4
Supporting identities	28	9	‘We feel identified with our natural and material heritage; we have no other identity than that’	3_NEI_B1
			‘The dry river is something we have always lived with here and it has very beautiful parts of vegetation. It is something peculiar to our own villages. Everyone sees it as something that is ours’	10_COU_2
			‘I try to have two or three trees of each species on my farm and I try to reforest the area with pines, mastic trees, and aromatic plants because for me this is the identity of the place’	3_NEI_B3

CRO_T: traditional crop farmer, NEI_B: basin-born neighbour, NEI_R: region-born neighbour, RES: researcher, TOU: tourism sector, ORG_E: environmental non-profit organisation, FIS: fisherman, COU: neighbourhood council.

Other leisure activities mentioned were sports (e.g. running, mountain biking, motocross, hunting in the upper part; fishing, diving, sunbathing in the lower part), ecotourism, family picnics, gardening, horse and donkey riding. Inhabitants also claimed to enjoy little-recognised values such as silence, tranquillity and connection with nature:

‘“I love this place. It has unrecognised values. For example, it has silence. There are very few landscapes with silence” (6_TOU_2); “El Cañar dry river is also a place of silence to be alone and enjoy.”’ (3_NEI_A1)

Inhabitants described diverse opportunities for learning and inspiration provided by dry rivers (Ni = 34; Figure 2; Table 2). For instance, traditional freshwater harvesting systems, traditional farming and grazing techniques, the use of vegetable fibres, herbs and aggregates, and traditional fishing gear are part of the traditional knowledge acquired over generations to adapt to aridity and fluvial dynamics (S4). Neighbours and non-profit organisations expressed how the arid landscape and its associated vegetation are a source of inspiration for their painting workshops.

Environmental managers, researchers and non-profit organisations mentioned conservation (e.g. The LIFE Project: Astragalus nitidiflorus, LIFE 11 BIO/ES/727 2016) and restoration projects (e.g. Adaptation of Dry Rivers to Global Change, ANSE 2019). Researchers in ecology (e.g. climate change experts), botany (e.g. medicinal plants, habitats), genetics (e.g. date palms), sociology (e.g. shepherd culture) and marine science (e.g. flora, fauna) use dry rivers as an experimental laboratory for their research. Other learning opportunities include guided nature walks and experiences with local people (e.g. goat milking, cheese making, esparto plaiting).

The NCP category of supporting identities was expressed through past experiences and emotions (Ni = 28; Figure 2; Table 2). The local people felt a strong rootedness for the biodiversity of the dry rivers (e.g. wildlife, aromatic plants), their traditional activities (e.g. carob cultivation, goat herding) and the landscape. They expressed different emotions such as pride and satisfaction when asked about their sense of place:

‘“Even if I had to leave here, the cattle and the land of my grandparents and parents would be in my blood” (1_CRO_T3); “Do you know the glory I feel when I’m driving the tractor and a flock of partridges appears in front of me?”’ (1_CRO_T3)

They also shared stories and experiences from their childhood that they remembered fondly. For example, the cultivation, healing and plaiting of esparto, which gave rise to their own customs (e.g. candangas) and language (e.g. filete), Christian pilgrimages among the riverside vegetation, and fishing days on the beach:

‘“I’d like to bring back the plaiting of esparto because I have such good memories of those candangas” (8_ORG_S1); “It was a great pleasure when we were kids, and not so kids, to fish our groupers from the pier.”’ (8_ORG_S2)

4.1.3. Regulating NCP

Regulation of freshwater quantity, location and timing was the most reported regulating NCP (Ni = 26; Figure 2; Table 3). Locals take advantage of dry river floods. They build pedrizas on cultivated floodplains to retain water longer, traditional ditches or acequias to transport water by gravity from dry rivers to more distant locations, aljibes for storing water for domestic use, irrigation ponds to cope with the dry season, and storage tanks to supply water to nearby towns. They even take advantage of the sea humidity to irrigate crops:

‘The most important crop was peas, which were irrigated with the hoe shaft. The soil was ploughed with the hoe and at night the mist soaked the earth. It was watered by the mists of the sea. I work with mist and rain.’ (3_NEI_R2)

Table 3. Regulating nature’s contributions to people (NCP) provided by dry rivers, as reported by interviewees. Regulating NCP are classified by applying the categories proposed by the generalising perspective of the intergovernmental science-policy platform on biodiversity and ecosystem services (IPBES) conceptual framework (Díaz et al. 2018). The number of interviewees (Ni) and social groups (Ng) reporting each NCP category are indicated. The NCP categories are exemplified by verbatim quotes from the interviewees.

NCP category	Ni	Ng	Examples (verbatim quotes)	Interviewee
Regulation of freshwater quantity, location and timing	26	9	‘Almost all dry rivers have traditional irrigation ditches. They used to live near these areas to grow their crops’	10_COU_1
			‘There we have been seven months without rain, but without rain at all, but with the water from aljibes you can live. You count how many you need’	3_NEI_R2
			‘Dry rivers have many stone terraces to slow down the runoff water so that it stays on the crops’	6_TOU_2
Habitat creation and maintenance	18	7	‘The wild boars wander along dry river in search of water, coolness and fennel roots. There are many of them’	6_TOU_1
			‘When you open the straw bales to feed the horses, you find inside nests of partridge and quail, small hares and rabbits’	4_HUN_2
			‘The trees close to dry river are a home for rabbits and a shelter for nets because they are not harvested’	6_TOU_2
Formation and protection of soils	16	9	‘In the past, the fields were sown and maintained with pedrizas to prevent erosion of the slopes’	1_CRO_T1
			‘Pomegranate trees were grown in the lower part of the crop terraces because they retained the soil and removed mineral salts from the plot’	3_NEI_R2
			‘Dry rivers carry stones and debris towards the coast, increasing its height. I couldn’t see the cars on the dry river from my house, but now I can see them almost completely because there is more soil now’	8_ORG_S1
Regulation of climate	7	4	‘The dry river is the coldest place. If you go there in summer and walk along El Cañar dry river, you will be cool’	6_TOU_1
			‘We are on The Oven Hill. The land is warmer here because underneath us there is a pit cave and a 200-metre-long lake, which warms the land together with the first rays of sunshine that always fall here’	6_TOU_1
			‘The area has a dry and harsh climate, but in dry rivers it becomes softer, allowing subsistence agriculture and the settlement of hamlets’	2_MAN_L1
Regulation of freshwater quality	5	4	‘People even collected dry river water and brought it to Cartagena city because it was mineral-medicinal’	3_NEI_B3
			‘There are two campsites with hot spring spas because there is a thermal water aquifer underneath’	8_ORG_E1
			‘We get our water from wells. I water my goats from the well at the old barracks on the dry river, because the water there is good. I extract it by hand with two buckets’	7_LIV_T1
Regulation of detrimental organisms	3	2	‘The carob tree is the only species right now that doesn’t catch pests’	1_CRO_T3
			‘There is a function that wild boar can perform, it is a great consumer of vinegar, which is a kind of invasive alien species in crops’	8_ORG_E2
Regulation of hazards and extreme events	2	2	‘Dry rivers collect rainwater. If there were no dry rivers here, there would be flooding’	6_TOU_1
			‘When it rains, dry rivers deteriorate a lot. However, there are no flooding problems, zero, it is more benefit than harm’	1_CRO_T2
Regulation of air quality	1	1	‘I think that this is as important or more important than a motorway because it is a lung that you have here and you have to maintain it with reforestation’	3_NEI_B3

CRO_T: traditional crop farmer, MAN_L: land environmental manager, NEI_B: basin-born neighbour, NEI_R: region-born neighbour, HUN: hunter, TOU: tourism sector, LIV_T: traditional livestock farmer, ORG_E: environmental non-profit organisation, ORG_S: social non-profit organisation, COU: neighbourhood council.

The second most reported regulating NCP was habitat creation and maintenance (Ni = 18; Figure 2; Table 3). Interviewees indicated that riparian vegetation and crops provide water, food and shelter for small mammals (e.g. foxes, badgers, genets), birds (e.g. partridges) and reptiles (e.g. lizards, tortoises). They also used the word biodiversity to refer to the vast variety of native plants:

‘People don’t know the varieties of orchids, daffodils and strawberry trees here. The biodiversity is amazing and the mineralogy of the soil favours the species to be different.’ (3_NEI_R2)

Fishermen reported that dry river mouth can be a habitat for some species such as breams, and non-profit organisations and environmental managers noted that dry rivers carry sediments, which contribute to the formation of dune and marine habitats.

Soil formation and protection was described as an essential NCP to agriculture (Ni = 16; Figure 2; Table 3). Crop farmers take advantage of the more fertile alluvial deposits located in the lower reaches and floodplains. Given the arid conditions, they work together with herders and neighbours to increase fertility. They apply organic fertilisers (e.g. goat manure, rabbit manure, fertile silt from aljibes), build pedrizas to prevent erosion, make crop associations to increase productivity (e.g. broad beans are sown under the shade of the palm trees), and establish different cultivation strips according to soil characteristics (e.g. cultivation of pomegranate trees in saline soil).

Climate regulation was perceived by local people (Ni = 7; Figure 2; Table 3). They expressed that dry rivers are cooler and shadier places than surrounding areas in summer when temperatures are higher. They, as well as livestock and wildlife, find refuge among riparian vegetation, crops, and small caves. They added that dry rivers are also pleasant places in winter, because there are springs and galleries with thermal water, and the sea breeze brings humidity, preventing frost and crop damage.

Freshwater quality regulation was barely reported (Ni = 5; Figure 2; Table 3). Interviewees cited the mineral, medicinal and thermal properties of water from small springs and aquifers, whose recharge depends on dry river floods. However, 46% of the interviewees claimed to use water from wells, traditionally drawn by a waterwheel pulled by a donkey for cooking, washing clothes and bathing, while goatherds and hunters water their animals. They also use water from aljibes, which is decanted and filtered with plant fibres such as thyme.

Interviewees noted the role of some native species in the [regulation of detrimental organisms] such as pests and invasive alien species (Ni = 3; Figure 2; Table 3). For example, carob tree resists pests in the area, thus limiting their spread.

Regulation of hazards and extreme events was perceived by interviewees residing in the upper and middle parts of the basin (Ni = 2; Figure 2; Table 3). They said they felt protected from flooding because dry rivers drain runoff water quickly into the Mediterranean Sea. They keep crops and property safe, but remain isolated until the flooding stops:

‘Some days I have had to wait to go to work and also to go home because if the dry rivers are flowing, you can’t cross them.’ (9_FIS_1)

They added that problems occur when humans constrict dry river channels. In contrast some inhabitants, especially from the lower basin, expressed concern as they have seen how floods sweep street furniture, motorhomes and even people into the sea.

Regulation of air quality was mentioned by one interviewee who described the basins as a green lung (Ni = 1; Figure 2; Table 3).

4.1.4. Maintenance of options

An environmental organisation and a research ecologist talked about conserving dry rivers and their biodiversity to provide new NCP in the future. They highlighted the role that some drought-adapted species could play now or in the future in providing new foods and essences (Ni = 2; Figure 2):

‘“There are oils from some native plants that can be considered for harvesting in the future and aromatic plants with essences not yet commercialised” (8_ORG_E2); “This landscape meets the conditions to develop new activities that could be profitable such as the cultivation of desert truffle or Aloe vera, and the breeding of native snails.”’ (5_RES_2)

4.1.5. Other NCP

Interviewees revealed that they use dry riverbeds as a connecting path to gain access to their homes and fields, and to bridge distance between geographically isolated villages, fostering social relationships (Ni = 22; Figure 2):

‘“The dry river was a path connecting places. When it flooded, it filled with sand, making it more accessible, because this is a mountain range with steep ravines” (4_HUN_2); “Here, believe it or not, the dry river is the only access we have for twenty families.”’ (8_ORG_S2)

They also use dry riverbeds for the transhumance of livestock (e.g. sheep), trade in goods (e.g. bread, fish) and even, in the past, the smuggling of tobacco, jewellery and fabrics:

‘“I lead the sheep across the dry riverbed. It takes me nine hours to walk the 20 kilometres to Valdelentisco” (7_LIV_I1); “El Cañar dry river was used for smuggling. During the war, flour, oil and foodstuffs couldn’t be transported, so they were traded through the dry river.”’ (1_CRO_T2)

4.2. Synergies and trade-offs between nature’s contributions to people in dry rivers

The code co-occurrence analysis revealed 60 types of interactions between NCP: 52 synergies and 8 trade-offs (Figure 3; S3A). Most synergies occurred between non-material and material NCP (12), and between non-material and regulating NCP (11). In particular, the main reported synergies by interviewees linked learning and inspiration (understood as the acquisition of traditional knowledge) with food and feed (Ni = 23), regulation of freshwater quantity, location and timing (Ni = 17), materials, companionship and labour (Ni = 16), supporting identities (Ni = 16), physical and psychological experiences (Ni = 14), and habitat creation and maintenance (Ni = 12). For example, interviewees attributed the production of staple foods (e.g. figs, almonds) to the acquired traditional knowledge of agricultural techniques (Table 4; S3B). They also highlighted the synergies linking food and feed with supporting identities (Ni = 17), regulation of freshwater quantity, location and timing (Ni = 16), materials, companionship and labour (Ni = 14), and physical and psychological experiences (N = 14). For example, the survival of some crops depended on freshwater harvesting systems from dry rivers (Table 4; S3B).

Figure 3. Synergies and trade-offs between the nature’s contributions to people (NCP) provided by dry rivers. NCP are classified according to the categories proposed by the generalising perspective of the IPBES conceptual framework. A category of NCP not included in the previous framework is also applied: access to villages and fields. Each line indicates the interaction between two NCP categories. The thickness of the line indicates the number of interviewees who reported an interaction (the thicker the line, the more interviewees). The interactions reported by more than five interviewees are shown numerically. Synergies are represented with grey lines and trade-offs with red lines.

Table 4. Synergies between nature’s contributions to people (NCP) in dry rivers most reported by interviewees. NCP are classified by applying the categories proposed by the generalising perspective of the intergovernmental science-policy platform on biodiversity and ecosystem services (IPBES) conceptual framework (Díaz et al. 2018). The NCP A either supports or increases the NCP B. The number of interviewees (Ni) and social groups (Ng) reporting each synergy are indicated, as well as examples based on verbatim quotes from the interviewees.

NCP A	NCP B	Ni	Ng	Examples (verbatim quotes)	Interviewee
Learning and inspiration	Food and feed	23	10	‘There was a livelihood because after several generations your grandfather would say plant a fig tree and we will have figs, four olive trees, four almond trees, four carob trees and reeds [A. donax] for the house’	6_TOU_2
Learning and inspiration	Regulation of freshwater quantity, location and timing	17	8	‘In the past, the wells were equipped with a water wheel that was pulled by animals to draw water. They are between 12 and 20 metres deep. The rope has clay bowls and is wound around the waterwheel. It was a source of wealth because where there was water there was life’	3_NEI_B3
Food and feed	Supporting identities	17	9	‘After the depopulation that took place, people still have sentimental ties because they were born there or because they cultivate their land’	8_ORG_E2
Learning and inspiration	Supporting identities	16	5	‘We carry out environmental education activities and traditional uses such as esparto plaiting workshops because we want to maintain our traditions and customs, as well as sea poetry workshops and excursions in the natural environment’	8_ORG_E1
Learning and inspiration	Materials, companionship and labor	16	7	‘The reed [A. donax] has always been cut at Christmas or in January for the roofs of the houses and in May it starts to grow green and beautiful again’	1_CRO_T3
Regulation of freshwater quantity, location and timing	Food and feed	16	8	‘In the old days, dry rivers had water intakes for irrigation and they were very important because if you irrigated once, you were saved for several months’	6_TOU_2
Food and feed	Physical and psychological experiences	14	7	‘We use zero-kilometre food in the ecotourism centre. We use our almonds and carob beans to make cakes, we make mousse with oranges from the orchard, we have cheesecake from here and seasonal fruits’	6_TOU_2
Materials, companionship and labor	Food and feed	14	8	‘In the old days, they had donkeys because you had to prepare and plough your land’	8_ORG_S2
Physical and psychological experiences	Learning and inspiration	14	8	‘Campillo de Adentro is a very beautiful area to behold, my wife painted an oil painting because it was full of chrysanthemums in bloom’	5_RES_4
Habitat creation and maintenance	Learning and inspiration	12	6	‘We observed that when we left the straw or hay to dry out until September, small hares and quail were sheltering underneath’	4_HUN_2

CRO_T: traditional crop farmer, NEI_B: basin-born neighbour, HUN: hunter, RES: researcher, TOU: tourism sector, ORG_E: environmental non-profit organisation, ORG_S: social non-profit organisation.

Most trade-offs occurred between regulating and non-material NCP (3), and between regulating and material NCP (3) (Table 5; S3C). In particular, the most reported trade-offs by interviewees linked physical and psychological experiences with regulation of freshwater quality (Ni = 6), habitat creation and maintenance (Ni = 3), and food and feed (Ni = 3). For example, interviewees stressed that increased caravanning harms the regulation of freshwater quality, and that motocross and rallying damage natural habitats and traditional crops (Table 5; S3C).

Table 5. Trade-offs between nature’s contributions to people (NCP) in dry rivers most reported by interviewees. NCP are classified by applying the categories proposed by the generalising perspective of the intergovernmental science-policy platform on biodiversity and ecosystem services (IPBES) conceptual framework (Díaz et al. 2018). The NCP A decreases the NCP B. The number of interviewees (Ni) and social groups (Ng) reporting each trade-off are indicated, as well as examples based on verbatim quotes from the interviewees.

NCP A	NCP B	Ni	Ng	Examples (verbatim quotes)	Interviewee
Physical and psychological experiences	Regulation of freshwater quality	6	3	‘They [motorhomes] pour the sewage into the dry river and when it rains, it all gets into the sea and forms a brownish mud on the rocks. These are chemical discharges that are destroying life’	8_ORG_C2
Physical and psychological experiences	Access to villages and fields	2	1	‘People hate it when motorbikes and quads tear up the dry river roads. They look at it with a lot of rejection’	3_NEI_B1
Physical and psychological experiences	Food and feed	3	3	‘I took pictures of the disaster [caused by the rally]. The dust rose 300 metres high and when it settled on the crops, it ruined the crops of small farmers’	3_NEI_R2
Physical and psychological experiences	Habitat creation and maintenance	3	2	‘Motorbikes destroy nests on the ground’	3_NEI_B3
Food and feed	Habitat creation and maintenance	1	1	‘Another traditional problem throughout the basin is agriculture. Farmers are moving closer to the dry rivers until they get into them and this destroys the potential riparian forests’	2_MAN_W2
Food and feed	Physical and psychological experiences	1	1	‘When the slope of dry river ends, sedimentary deposits appear and industrial agriculture penetrates further. This alters the landscape and reduces its values’	5_RES_2

MAN_W: water environmental manager, NEI_B: basin-born neighbour, NEI_R: region-born neighbour, RES: researcher, ORG_C: cultural non-profit organisation.

The NCP categories involved in the largest number of synergy types were food and feed (13 types), learning and inspiration (12), and physical and psychological experiences (11). The NCP categories involved in the largest number of trade-off types were physical and phycological experiences (5 types), and food and feed (4) (Figure 3; S3A).

5. Discussion

5.1. Nature’s contributions to people in dry rivers

The interview analysis revealed that the interviewees perceived multiple material, non-material and regulating NCP (Figure 2). The NCP categories perceived by the most interviewees belonged to the material and non-material NCP groups, while the categories perceived by the least interviewees belonged to the regulating NCP. This imbalance may be due to the fact that material and non-material NCP involve strong, easily recognisable socio-cultural factors (e.g. cereal harvesting, esparto plaiting, pilgrimages) while regulating NCP rely on less obvious biophysical factors related to biodiversity and ecosystem functions (e.g. functional traits of biodiversity, nutrient cycling) (Camps-Calvet et al. 2016). For example, the NCP category of pollination and dispersal of seeds was overlooked, despite the fact that dry river vegetation supports pollinators (Martínez-Yoshino et al. 2021) and family beekeeping has been traditionally practised (DGMN 2006). Similarly, interviewees reported the NCP category of habitat creation and maintenance only for vertebrates and native plants, but not for ground-dwelling invertebrates despite their considerable abundance in dry riverbeds (Sánchez-Montoya et al. 2016, 2020a, 2020b). The methodology, based on semi-structured interviews and open-ended questions, facilitated the identification of one NCP not attributable to any category of the generalising perspective of the IPBES framework: access to villages and fields through dry rivers. This NCP was reported by more than half of the interviewees, reinforcing the evidence documented in the literature (Gómez et al. 2005; Steward et al. 2012).

Although a few NCP were produced solely by the natural system (e.g. regulation of temperature and air quality by dry river vegetation), most were co-produced by natural and social systems (e.g. food and feed, formation and protection of soils) (Díaz et al. 2015). The two types of co-production defined by Palomo et al. (2016) occur in dry rivers. In general, material and regulating NCP were co-produced by dry rivers and a physical contribution from the social system (physical co-production). For example, the regulation of freshwater quality depended on dry rivers and their aquifers (natural system), but also on the building of wells and waterwheels for water extraction, and water purification cisterns (social system). Instead, non-material NCP were co-produced on the basis of the social system’s experiences with species and landscapes of the natural environment, which generated emotions, feelings and knowledge (cognitive co-production). For instance, the satisfaction of watching the partridges or the relaxation stimulated by the silence of the landscape.

Based on the values that interviewees ascribed to the natural system, the same element of an ecosystem (e.g. a plant species) could provide more than one benefit (Díaz et al. 2015; Topp et al. 2020). For example, donkeys and mules were identified as a provider of material NCP (e.g. agricultural labours, transport of materials), but also non-material NCP (e.g. riding for recreation, aesthetic enjoyment, supporting identities), contributing to different components of quality of life, such as food and income security, access to recreation, and sense of place (Brondízio et al. 2019). Likewise, crops were identified as a provider of material NCP (i.e. food and feed), as well as of regulating NCP (i.e. soil protection and freshwater retention).

5.2. Co-production models affect synergies and trade-offs

The code co-occurrence analysis between NCP categories revealed that the involvement of the social system in the co-production processes intensified the NCP of dry rivers and promoted synergies between them. For example, wild asparagus and dates contributed in a limited way to food and feed provision. However, the cultivation of cereals and nuts intensified this benefit while promoting supporting identities (Figure 3; Table 4). Trade-offs were also promoted, especially between new (e.g. motorsports, caravanning) and traditional human activities (e.g. agriculture, habitat maintenance). For example, the rallies affected crop habitats by covering them with dust, and destroyed ground nests of importance to the local community (Table 5). Sometimes the same NCP promoted either a synergy or a trade-off, depending on the management. For example, while the NCP category of food and feed was identified as a promoter of supporting identities through traditional crops (synergy), it was also identified as a detriment to habitat maintenance through agricultural intensification (trade-off) (Figure 3; Table 5).

Synergies and trade-offs between NCP categories did not always operate in the same direction. It is common that NCP category A can influence NCP category B at the same time that NCP category B influences NCP category A (Bennett et al. 2009). For example, the rise of motocross (i.e. physical and psychological experience) was detrimental to traditional crops (i.e. food and feed), but the agricultural intensification (i.e. food and feed) was detrimental to the aesthetic enjoyment of the landscape (i.e. physical and psychological experience) (Table 5).

The code co-occurrence analysis revealed more synergies (52) than trade-offs (8) between the NCP of dry rivers (Figure 3; S3A). This is a consequence of a sustainable NCP co-production model acquired over generations by the social system, which has provided them with a wide range of NCP (Quintas-Soriano et al. 2022; Vidal-Abarca et al. 2022). Therefore, there are no human activities that promote specific NCP to the detriment of others, beyond the trade-offs reported by some interviewees. In addition, the environmental protection figures have probably helped to regulate human activities in recent times (DGMN 2006). The NCP of dry rivers reported by interviewees and their synergies support the study hypothesis that dry rivers provide multiple NCP through co-production processes (Comberti et al. 2015; Palomo et al. 2016).

5.3. Traditional knowledge underpins nature’s contributions to people in dry rivers

Learning and inspiration was one of the most reported NCP categories by interviewees (Ni = 34) and social groups (Ng = 10). It was also one of the NCP categories that had the most synergies with the other NCP categories (12). Moreover, many of these synergies were the most reported by interviewees (Figure 3). These results demonstrate that learning and inspiration play a key role in supporting many other NCP categories. Learning and inspiration can be understood as the capacity of dry rivers to provide opportunities for people to acquire traditional knowledge (Díaz et al. 2018). This knowledge is ultimately responsible for supporting many NCP categories co-produced between dry rivers and social systems (Iniesta-Arandia et al. 2014; McElwee et al. 2020; Guo et al. 2021). For example, traditional knowledge of floodwater harvesting systems such as acequias and aljibes contributes to freshwater regulation (Morales-Gil 1968; García-Llorente et al. 2015; Palomo et al. 2016); traditional knowledge of cultivation (e.g. terraces, crop associations) and pastoralism systems (e.g. seasonal transhumance) contributes to the provision of food and feed (Vidal-Abarca et al. 2022); and traditional knowledge on the use of indigenous plants contributes to medicinal and material resources (Jacobson et al. 1995).

Traditional knowledge is undervalued by decision-makers and it is rarely included by governments in their global change adaptation strategies (Nyong et al. 2007; Zvobgo et al. 2022). In recent decades, this knowledge has been compromised by rural exodus, economic globalisation and land-use change (e.g. agricultural intensification, land abandonment) in many farming systems (Aswani et al. 2018; Guo et al. 2021), including dry rivers (Jacobson et al. 1995) and Mediterranean systems (Iniesta-Arandia et al. 2014; Arnaiz-Schmitz et al. 2018; Plieninger et al. 2022; Quintas-Soriano et al. 2022). The loss of traditional knowledge jeopardises the sustainable NCP co-production (Comberti et al. 2015) and the conservation of species of human interest (Arnaiz-Schmitz et al. 2018). In the case of the dry rivers studied, the loss of this knowledge would affect 71% of the NCP categories such as food and feed, freshwater regulation, medicines resources, materials, supporting identities, and physical and psychological experiences, affecting the quality of life of the social system (Figure 3).

Recent research considers traditional knowledge as an opportunity to address new environmental challenges through sustainability science (Nyong et al. 2007; Comberti et al. 2015; Recha et al. 2016; Mastrángelo et al. 2019). For example, incorporating this knowledge into the development of climate change mitigation and adaptation strategies in Africa has been proven to increase their effectiveness, especially in arid lands (Nyong et al. 2007; Zvobgo et al. 2022). In Jordan, the ancient floodwater harvesting system of 6000 years ago inspired decision-makers in the mid-1990s to develop a modern system called earth ponds for sheep and domestic use (Alkhaddar 2003); and in Iran, qanat is a groundwater harvesting system through wells that has enabled water supply for centuries (Nasiri and Mafakheri 2015) and underground cultivation chambers are a system to cultivate grapevines (Tahmasebi 2009). In dry rivers, traditional systems of water harvesting, agriculture and pastoralism could be revived to cope with global change in arid regions where NCP provision is threatened (e.g. Rotich and Mulungu 2017).

The role of traditional knowledge in the NCP co-production opens up three lines of future research in dry rivers. First, to assess the capacity of traditional knowledge to contribute to a good quality of life in parallel with addressing environmental problems such as climate change (Tahmasebi 2009; Nasiri and Mafakheri 2015; Zvobgo et al. 2022). Second, to identify the drivers that undermine this knowledge and the factors that protect it, such as gender aspects or protected areas (Iniesta-Arandia et al. 2014). Third, to make decision-makers aware of the value of this knowledge so that it can be integrated into sustainable management policies (Jacobson et al. 1995; McElwee et al. 2020). Addressing these lines requires a transdisciplinary approach capable of integrating and responding to environmental, social, political and economic issues in a collaborative way (Jahn et al. 2012; Lang et al. 2012).

5.4. Traditional knowledge influences social perception of dry rivers

Society at large perceives that the capacity of dry rivers to provide NCP is low compared to that of perennial rivers (García-Llorente et al. 2012; Koundouri et al. 2017; Rodríguez-Lozano et al. 2020; Vidal-Abarca et al. 2020). However, the interviewees perceived as much diversity of NCP from dry rivers in the study area as that described in the literature for perennial rivers (Yeakley et al. 2016; Hanna et al. 2017). These two opposing views of dry rivers can be explained in part by the traditional knowledge acquired by the local community. Traditional knowledge underpins most of the processes of NCP co-production by conditioning the social perception of the livelihood opportunities that dry rivers can offer to people. For example, society at large and some interviewees from the lower parts of the basins perceived flash-floods as a detrimental NCP because they can drive important human and material damages (Di Baldassarre et al. 2010; Quiñonero-Rubio et al. 2011; Winsemius et al. 2018; Sánchez and Toro 2020; Diakakis 2022), which are often associated with inadequate land management (Pérez Morales et al. 2016). In contrast, given that freshwater is a scarce resource, most interviewees perceived flash-floods as a relevant beneficial NCP (Jorda-Capdevila et al. 2021) for harvesting freshwater, irrigating crops and generating energy, despite temporary road closures they cause. Similarly, interviewees reported benefiting from their knowledge of wild edible plants, plant fibres and medicinal herbs that might be inaccessible to the rest of society without such knowledge (Fischer and Eastwood 2016; Rodríguez-Lozano et al. 2020). Nevertheless, other socio-demographic factors such as physical abilities, perceived rights, educational history and leisure activities may also play a role in the social perception of dry rivers (Fischer and Eastwood 2016; Rodríguez-Lozano et al. 2020; Jorda-Capdevila et al. 2021).

6. Conclusions

Dry rivers can provide as much diversity of material, non-material and regulating NCP as perennial rivers, but with one unique NCP: access to villages and fields through dry riverbeds. The success of this broad provision of NCP lies in their co-production between dry rivers and associated social systems. The NCP co-production not only increases the diversity of NCP from dry rivers, but also promotes many synergies between them, with some trade-offs. The dry rivers in the study area have provided the social system with the opportunity to acquire traditional knowledge over generations to effectively manage floodwaters, native plants and animals, and abiotic materials. This suggests that traditional knowledge may be one of the key pillars currently supporting NCP co-production in dry rivers, and therefore a factor influencing social perceptions of dry rivers. Integrating traditional knowledge into research and governance can help raise awareness of the NCP in dry rivers and contribute to the development of adaptation and mitigation strategies to climate and global change. To achieve this goal, the next research steps should be: i) to assess which NCP of dry rivers are most valued by social systems, ii) how each NCP contributes to the different components of quality of life (e.g. water security, good social relationships), and iii) to identify the main drivers that alter these NCP.

Credit authorship contribution statement

NNR, MRVA and MLS designed the research and conducted the interviews. NNR and CQS analysed qualitatively the interviews. All the authors discussed the results. NNR wrote the first draft of the manuscript. CQS, MRVA and MLS reviewed the subsequent versions of the manuscript. NNR and MRVA designed the figures and tables. All the authors read and approved the final manuscript for publication.

Ethics approval

The authors state that all interviewees were correctly informed about the dynamics of the interviews and the processing of the data. All individuals accepted the consent form. No individual can be identified in this work.

Acknowledgements

The authors would like to thank Berta Martín-López for introducing us to the fantastic world of socio-ecology and encouraging us to explore it. We would also like to thank the following for their participation in this study: EDAR Isla Plana – La Azohía, La Azohía Women’s Association, Miguel Ángel Esteve, Francisco Solano, Diane McCarthy, Lisa Gibbs, Antonio Ros, Críspulo Arroyo, Cabo Tiñoso Ecotourism Project, José Martínez, Directorate for the Natural Environment of the Region of Murcia, Juan Diego Celdrán, Natalia Martín, Isabel Andreu, ADELA, Friends of the Blue Diving Centre, José Antonio García, Bonnysa Agroalimentaria SA, Diego Rivera, ANSE, Almadraba La Azohía SA, ACUAMED, Francisco José Almagro and Carlos Pardo, who agreed to be included in this section, and all those who decided to collaborate with us anonymously. Finally, we would like to thank María Isabel Arce for her help in revising the English version.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/26395916.2023.2288953

Additional information

Funding

This work was supported by the Spanish Ministry of Economy, Industry and Competitiveness, State Research Agency and European Regional Development Fund (ERDF) under Grant CGL2017-84625-C2-2-R. NNR was supported by a pre-doctoral grant from the Séneca Foundation (Science and Technology Agency of the Region of Murcia, Spain). CQS was supported by EU funding through the Marie Sklodowska–Curie grant number 101031168.