Multicriteria spatial analysis applied to identifying ecosystem services in mixed-use river catchment areas in south central Chile

Natural systems provide numerous goods and services to human society, supporting human welfare and economic prosperity (MEA 2005). Among these goods and services are food production, regulation of the climate, water regulation, etc. (de Groot et al. 2002). Broadly speaking, Ecosystem Services (ES) are the conditions and processes through which natural ecosystems help to sustain human life (Daily 1997). Costanza et al. (1997) define them as those benefits which human populations receive directly or indirectly from ecosystem functions, defined as a set of ecological processes in the structure of an ecosystem (de Groot et al. 2002). Therefore the production of an ES will depend on the structure and processes of an ecosystem; any factor which has an impact on the ecosystem will affect its processes as well as the flow of benefits generated by the ecosystem for society (Costanza et al. 1997; Daily 1997; de Groot et al. 2002; Esse et al. 2014).

In Chile, the current conceptual framework defined by the Environment Ministry (MMA) establishes a classification of ES based on Haines-Yong and Potschin (2013) and Haines-Young and Potschin (2018), who divide these services into: 1) support, intermediate and final services provided by the environment, and 2) the goods and benefits of the economic and social system. Thus we may say that ecosystems are the basic functional units of the ecology, in which we can recognise the constant interaction between biotic and abiotic components (Odum 2004). Ecosystem studies concentrate on describing biological phenomena from a systemic perspective. They involve the three variables which allow these ecological units to function, namely energy flows, nutrient cycles and biomass generation (Rees 2018).

Starting from the conceptual framework proposed by the Millennium Ecosystem Assessment (MEA 2005), a more explicit link has been established between how a service is provided and how society benefits from it (ecological and economic integration of ecosystems), relating function and ES with the benefit to society. MEA (2005) classifies ecosystem goods and services into four categories: (1) Provision: associated with tangible goods or products obtained from ecosystems; (2) Regulation: benefits obtained from the regulation of complex ecosystem processes by which environmental conditions are regulated; (3) Cultural: immaterial benefits obtained from ecosystems; and (4) Support: basic ecological processes to ensure proper ecosystem functioning and the flow of provision, regulation and cultural services. Other classifications exist, such as those proposed by Boyd and Banzhaf (2007), Wallace (2007), Fisher and Turner (2008) and TEEB (2010); they differ in the breadth and complexity of their approaches.

In geographical space, where the processes which generate the various ES occur, the territorial dimension is an integrating element which must be carefully studied (Zasada et al. 2017). Sánchez (2009) stresses the importance of territory, due to the endogenous capacity of actors to establish connections and flows, both material and immaterial; linking those involved who are inserted in different and sometimes distant territorial scales. Thus the spatial representation of ES in the territory allows the public resources and policies for safeguarding these services to be properly directed (Esse et al. 2014). Citizen participation is a key aspect; it must be considered when ES are being identified (Verburg et al. 2016), since the inclusion of local actors allows respect for their identity and other aspects which are unlikely to be recognised. Little attention is usually paid to this aspect in policy planning and drafting (Braat and de Groot 2012), where the tendency all over the world is towards the ‘upscaling’ model (Larsen et al. 2012), using results as the basis for larger-scale policies, for example at national level. In citizen participation processes, the leading actors in the territory possess more information on the flow of goods and services produced in the environment where they carry on their own productive activities (Costanza and Shuang 2014); their perception does not always coincide with that of specialists and researchers, who seek to understand the flow of goods and services by establishing a conceptual model (Hermelingmeier and Nicholas 2017) which excludes the knowledge of those who live in the territory. This needs to be corrected to achieve greater accuracy and knowledge about ecosystem production derived from the physical medium (Peterson et al. 2018), as occurs when the functioning of native forest is compared with that of forestry plantations.

In the mid-nineteenth century, the forest landscape of Chile underwent a major transformation due to the felling and burning of vast expanses of native forest to clear land for arable and livestock farming (Donoso and Otero 2005; Otero 2006). A hundred years later, the industrial forestry sector was promoted by the passing of the Forest Law and Decree Law No. 701, the object of which was to regulate the felling of native forest and provide incentives for the recovery of degraded soils by installing plantations of fast-growing exotic species (Otero 2006). As a result, there is now growing discussion in south central Chile about the forestry industry and the replacement of large expanses of native forest to promote farming production (Miranda et al. 2015), and the possible impact that this has on ecosystem functioning in river catchment areas, and especially on the services associated with water production and quality (Oyarzún et al. 1997; Soto 2002; Naiman et al. 2005; Richardson et al. 2007; Lara et al. 2009; Little et al. 2009; De los Ríos Escalante et al. 2017). This situation has led the inhabitants of these basins to assert their agreement with criteria for the conservation and preservation of native forest; they are supported by Law 20.283, which regulates the recovery of native forest and promotion of the forestry industry, in order to avoid restrictions on the production of forest goods and services and damage to the potential development of local economies.

In view of the above, our purpose was to assess the social value assigned by important actors in the territory to the production of goods and services by secondary N. dombeyi forests in a catchment area with multiple land-use. We expected to find significant recognition by important actors of the production of goods and services by N. dombeyi forests as compared to other land-uses. The object of the present study was therefore to identify and analyse the social value of ES, considering different levels of perception in a catchment area which supports a variety of forestry and farming activities. We hope that the results will help in the drafting of public policies to regulate activities in the territory, contributing an easily-applied methodology for including the perceptions of the territory’s inhabitants and leading actors.

This study shows that catchment areas are complex systems; they support different ecosystem processes which are usually particular, individual and characteristic, making comparison between them difficult (Esse et al. 2014). These territorial units present different ecosystems throughout their length and breadth, incorporating boundaries which are not merely political or administrative borders, as noted by Rodríguez (2006), Vuscoviuch and Tavares (2011) and Gómez-Orea and Gómez (2014). Proper study requires tools for quantifying and mapping the various components, in order to dimension the flows of goods and services occurring in the basin (Laterra et al. 2011; Esse et al. 2014). The technologies derived from geographical information systems (GIS) and remote detection offer high quality detail and remote observation of the various ecosystems which make up a territory. The results of this study show a methodology that incorporates easy-access technological tools and allows precise information to be obtained on environmental components, similar to Keller et al. (2015); Basco-Carrera et al. (2017); Diaz-Balteiro et al. (2018). The identification of benefits is assisted by the inclusion of leading actors, whose perceptions contribute information on the effects of resource handling and management, and how these relate to conservation plans in the framework of co-management of river catchment areas. Multicriteria analysis methods are a way of discovering the perceptions of the territory’s inhabitants while minimising the bias in appreciation. Other researchers have obtained good results using these techniques (Keller et al. 2015; Uhde et al. 2015; Diaz-Balteiro et al. 2018), however the present study proposes a hybrid model which allows spatialisation of the perception of the important actors with respect to ES production, facilitating decision-making for territorial planning and the formulation of public policies. A view of the consequences for land-use of such decisions, incorporating the complexity of the natural environment and its variations in time and space, is indicated by Bateman et al. (2013) as an advantage for decision-making in government policies, demonstrating the advantages of the method applied in this study. Nevertheless, the method presents certain deficiencies such as the scale of the analysis, dependence on territorial cartographic bases and the representativeness of the important actors from the territory who participated in the workshops; all these aspects may affect the quality and accuracy of the model; however, they can be improved as a function of the proposed objects.

The results show that the historical use of the basin has encouraged the growth of arable farming and stock-raising; in fact only 8.6% of the total area consists of plantations of exotic species, while arable farming and stock-raising occupy 34.7%. Both these activities have been responsible for the substitution of native forest, according to Díaz (2006). This may lead to greater contamination of water bodies, species loss, habitat reduction etc. (Habib et al. 2016; Dassou et al. 2017; De los Ríos Escalante et al. 2017), as well as contributing to the impact on the world CO₂ balance by increasing the accumulation of greenhouse gases (GHG) and thus promoting climate change. This is suggested by the leading actors of the area, who recognise the negative effects of these two activities on the ecosystem, especially on N. dombeyi forest and the water production and quality services associated with this species. Consequently the leading actors attribute greater social value to areas covered with N. dombeyi forest, making it clear that the forestry industry (monocultures) is a business which benefits very few people and does not contribute significantly to the local economy. At the same time, farming bears the greatest responsibility for the disappearance of native forest in the basin, and for generating water pollution and a reduction in soil productivity.

The transformation of large areas from native forest to land-uses like farming and forestry plantations modifies the water flow and supply significantly; this may affect economic activities, as remarked by Habib et al. (2016). Oyarzún et al. (2005) indicate that economic activities related with the production and consumption of market goods like drinking water may be severely affected. The result may be that changes in the production of market goods are passed on to society through the pricing system, affecting people’s welfare. The results showed that although they contain sectors of severely degraded native forest, riparian areas possess a high value, since they have a recognised function in water provision, the regulation of bio-geochemical processes and cultural aspects, particularly natural beauty and tourism. These areas are fundamental in the territorial unit, and must be properly managed by policies to encourage and incentivise their conservation, allowing a balance between use and the production of goods and services. One object of a management proposal (Fig. 5) should be the restoration or bio-remediation of such areas.

Most of the provision services identified refer to tangible goods, including water, wood, NWFP, fibres, etc. Turning to regulation services, the results show that these are closely related to air and water quality regulation, as they help to maintain bio-geochemical cycles. They are also directly associated with the presence of native forest, and they are recognised and valued as vital services for human welfare, in agreement with MEA (2005), Lara et al. (2009) and Little et al. (2009). For cultural services, native forest is the most valuable unit in the territory, since local actors associate its presence with natural beauty, the culture and world-view of the Mapuche people, tourism, education and research; these results agree with Esse et al. (2014). Cultural services offer benefits which depend on the collective perception of society, a fact which reveals the social importance attributed to the spiritual, recreational and educational benefits provided by ecosystems. Thus, the methodology applied, based on MSM, represented efficiently the value of the territory, since it was able to express the perception of the inhabitants of the study area in the spatial plane. This allows options to be created for socio-ecological management through local decision-making, which can be applied on a regional scale as detailed by Larsen et al. (2012). This scaling can be applied in Chile through the authority of the municipal governments to pass mandatory general standards applicable to the local situation, adapted from laws passed at national level (Santander-Massa 2014).

Forestry activity and the replacement of large areas of native forest have altered the ecosystem functioning of the study catchment area, leading to a critical appreciation of such activities among leading actors in the basin. Earlier studies, such as Lara et al. (2003), Echeverría et al. (2006), Lara et al. (2009), Miranda et al. (2015), indicate that the landscape of south central Chile has undergone a series of transformations in recent decades; drastic changes and intense pressure on land-use have resulted in incompatibility between different goods and services. The factors responsible for these changes have been activities like clearing land for agriculture, use of fire, deforestation and degradation of natural forests in areas of high biodiversity (Habib et al. 2016), and wood production in fast-growing plantations relying on irrigation. This reflects the historical reality of the study basin.

The results of the present study recognise the social value of a local viewpoint. This is of great importance for the country’s economic development, since it highlights the fact that the conflict between forestry producers and farmers is basically economic, and that their respective positions do not recognise the impacts that they have caused on the ES provided by the territories where they carry on their activities. Thus the participation of the leading actors of the territory is fundamental for generating public policies whose final object is to safeguard the ecosystem functioning of such important areas as river catchments.

A number of very varied land-uses may be identified in a river catchment area. For this reason, an ecological approach based on ecosystem functioning will give unique, individual results which are unlikely to be comparable with those of other similar geographical units. Correct identification and value attribution of ES will contribute to correct description of the flow of the goods and services affecting the territory.

The important actors of the territory recognise the importance of native forests, and that they are fundamental for the maintenance of ES related with water production and flow regulation. This is particularly so in the case of N. dombeyi forests, which grow in damp conditions associated with watercourses, covering riparian areas. N. dombeyi therefore has great potential for use in plans for the restoration of riparian areas.

The methodology used in this study, based on multicriteria spatial analysis, enabled us to represent the territory at landscape scale and to recognise the social value of the different ES of the natural ecosystems and anthropic production systems of which it is composed.

The participation of the leading actors of the territory is fundamental for achieving a proper valuation scale for the different ES; they contribute a broad perspective on territorial management which goes beyond the particular interests of productive sectors such as farming and forestry. Their participation must be reflected in the definition of public policies for the sustainable management and conservation of natural ecosystems.