1. Introduction
Ecosystem services (ES) are defined as benefits that people obtain directly or indirectly from ecosystems, which are usually classified as provisioning, regulating, or cultural [
1,
2,
3,
4]. In this sense, wetlands provide a wide range of ES that contribute to human well-being [
5,
6,
7,
8], including algae and fish, ornamental species, natural disaster mitigation, microclimate regulation, aesthetic value, and tourism, among many others [
1,
9,
10]. Thus, it is important to ensure the ecological integrity of these ecosystems to guarantee the continuity of their provision of ES. However, on a global scale, many studies agree that their loss and degradation are greater than those of other ecosystems, and are more severe in freshwater and coastal wetlands, particularly in the Mediterranean region [
3,
11,
12]. In coastal wetlands, drivers of change are associated with direct (land-use cover changes, diversion of freshwater flows, changes in water temperature, and species invasions) and indirect factors (human population growth and increasing economic activity) [
1,
3]. However, some natural disasters (e.g., earthquakes, tsunamis, volcanic eruptions, storms) can cause abrupt disturbances in these ecosystems [
13,
14,
15,
16], therefore altering their ES provision.
This paper focuses on the social perception of ecosystem services in a coastal wetland in Chile, which were disturbed by a major earthquake. Salt marshes are a type of wetland that are especially sensitive to such disturbances. The ecosystem function of salt marshes depends on the interaction of fresh and salt water, which occurs in estuarine channels [
17,
18]. Large earthquakes can have an appreciable impact on the morphology and evolution of tectonically active coastal areas [
17]. Depending on the coseismic tectonic dynamics of the affected area, the coast may undergo subsidence and/or uplift [
19,
20]; in the latter case, the tidal inflow into the estuary is diminished due to the close relationship between the altitude of the wetland and the local sea level [
17]. For example, the relationship between ecosystem status and earthquakes was observed in the Sumatra–Andaman earthquake (
MW = 9.1), where the coseismic uplift (0.3–1.5 m) caused plant mortality in large areas of coastal mangroves mainly due to thermal shock, desiccation, and the gradual depletion of soil salinity [
21]. Earthquakes and tsunami disturbances have been associated with severe impacts on local human communities, due to the devastation of their crucial subsistence resources, as reported historically in the southern northwestern coast of the United States [
13].
The above-mentioned cases demonstrate the complex links between the natural and social systems associated with human well-being [
1,
4,
14]; therefore, it is important to incorporate social perceptions, historical drivers of change, trends, and social values in the evaluation of ES to guide criteria for sound environmental management strategies [
3,
22], an approach that is gaining prominence in the ES research agenda [
23]. The social approach focuses on the values that society attributes to each ES [
24] and considers that all individuals establish judgments and values regarding ecosystems and landscapes [
25], which implies a diversity of individual values, interests and lifestyles, and thus an appreciation that depends on each context [
7,
26,
27].
The perceptions and preferences of the population regarding ecosystem services are influenced by a series of personal, geographic, and social characteristics such as age, gender, income, political orientations, environmental organizations, moral convictions, use and non-use of particular areas, life experiences, and living environment [
4,
22,
23]. Maestre-Andrés et al. [
28] identified education, age, and place of residence as the characteristics that most affected the sociocultural valuation of ES in a nature park (Spain). Other studies have identified ES provision based on the perceptions of the local people [
2,
3,
7,
22,
28,
29]; however, few have focused on the time after the occurrence of a major disaster (see Reference [
14]), which is a priority in developing countries, where it has been estimated that the effects of the loss of ecosystem services on human well-being will be serious due to the low incomes and land-based personal economies of the affected populations [
5]. Therefore, in areas prone to natural disasters, the analysis of current perceptions of ES and the understanding of their trends and drivers of change are of increased importance to maintain biodiversity, ecosystem functions, and assure population well-being.
Located in South America, Chile is a developing country that is highly exposed to natural disasters. The central region of Chile has a history of destructive earthquakes (1575, 1580, 1647, 1730, 1822, 1906, 1985 [
30,
31]) with the most recent event being the 2010
MW = 8.8 earthquake, that devastated south-central Chile [
31]. The 2010
MW = 8.8 earthquake caused substantial morphological, social, and environmental changes in the coastal area of central Chile [
15,
32,
33,
34,
35,
36,
37]. One of the most affected sectors was the Tubul-Raqui fishing village, located south of the Concepcion metropolitan area (thereafter CMA). Here, the Tubul-Raqui salt marsh offers ES provision mainly to a rural population with a high poverty rate [
34,
37]. In this area, the 2010 earthquake generated a coseismic coastal uplift estimated at 1.62 ± 0.22 m (see Reference [
20]), these dynamics have previously been observed in other events such as the great earthquake of 1835 [
31,
38]. The coastal uplift interrupted the entrance of the tide and partially dried the salt marsh, and generated a variation in the availability of ES provision, associated mainly with the extraction of the alga
Gracilaria sp. (or pelillo in Spanish), which is important for the maintenance of the local economy [
37,
39,
40]. In this context, we analyzed the social perception of the inhabitants of the village of Tubul-Raqui on the coast of central Chile to assess ES provision after the occurrence of a large earthquake. The data and methods applied can be replicated in areas of high ecological value affected by major disasters to understand the importance of ES after a great disturbance, therefore allowing an understanding of the implicit sociocultural differences based on each context.
4. Discussion
The perceived benefits of ES provision following a large disturbance such as the 2010
MW = 8.8 earthquake provided a view of the positive valuation of the inhabitants of a Mediterranean salt marsh, which has been declared a Chilean priority site under the National Strategy for Biodiversity Conservation [
41]. In general, it was observed that the regulating and cultural ecosystem services obtained a high valuation in terms of frequency of provision despite morphological, social, and environmental changes from the last earthquake. In fact, in the regulating services, the high recurrence of natural (tsunamis, floods) and anthropogenic disasters (fires) that affect the Chilean Mediterranean region [
31,
37,
51] may have positively influenced the utilitarian valuation of the wetland by the population, as it forms part of the inhabitants’ collective memory. This is not novel, and is consistent with Barbosa and Villagra [
52] as wetlands are essential to mitigate the effects of such catastrophes, and are socially valued as spaces of recovery after earthquakes, especially if they provide biophysical attributes such as water [
53].
A similar situation (high social perception) regarding regulating services occurred in the habitat for species service, in the study of Marín et al. [
54], carried out 18 months after the earthquake, the diversity of bird species was one of the most important ES perceived by the inhabitants of the Tubul-Raqui fishing village. This perception can be linked to daily observations of the abundant biodiversity provided by the wetland, including local and migratory bird species (83), micromammals (4), reptiles (6), and amphibians (1), which provides a unique sense of landscape beauty. In this regard, the role of collective memory was fundamental. Kunstler (1994), cited by Bouahim et al. [
3], recognized the importance of that and the beauty of places in promoting a sense of attachment and human belonging, both key factors in perception studies. Furthermore, Dobbie and Green [
4] indicated that intrinsic (habitat, social, esthetic, educational, and tourism) values often dominate the perception of wetlands.
The highlighted result showed that the valuation of cultural services was the highest, with the Tubul-Raqui salt marsh identified as an ecosystem capable of providing opportunities for services related to recreation, local identity, science, and environmental education, as also demonstrated in Australia and the United States [
4]. For example, according to Lindborg et al. [
55], the positive perception of ES provision is dependent on the connection of people to the landscape, which has been linked to low-intensity primary activities (e.g., agriculture), where habitats maintained in a semi-natural landscape state can offer biological, cultural, and heritage values, a situation similar to that reported in Tubul-Raqui regarding the intensity of economic activities. Regarding science, the opportunities for scientific research and environmental education were also highly recognized; the perception of these two services could be related to the large number of studies carried out in the wetland due to the environmental problems that emerged after the 2010 earthquake with various groups of scientists conducting research aimed at assessing the impact and socio-environmental recovery of the system [
33,
34,
37,
39] where studies have involved surveying the population and the use of artisanal fishing boats.
Regarding the negative valuation of provisioning services, in the case of water, fuelwood, livestock, and crop development, the results were impressive, especially in water provision, which could have been influenced by the inherent environmental conditions of the system with its low-quality soils and brackish water that do not favor intensive extraction activities or the provision of these services [
39]. This situation was in agreement with Bouahim et al. [
3], who stated that an increased perception of provision was related to the dependence of the survey respondents on the corresponding ES provision. Algae and fish obtained a greater valuation, even though the official data indicated a significant drop in pelillo extraction, an increase in unemployment, and a decrease in incomes following the 2010 earthquake [
37]. Indeed, Marin et al. [
54] indicate that navigation and algae services were completely lost after the event. In this study, the greater social perception of the fish and algae production service is explained by three factors. First, this valuation can be explained by the influence of categorical variables, which revealed a greater perception of the service and its benefits by young people, ethnic groups, and people not connected to the primary economic sector, which are also groups that mostly do not engage in extraction activities, a key aspect for making an accurate valuation of the ecosystem service [
7], a situation related to the selection procedure of the population inherent to the study.
A second factor is related to the General Fisheries and Aquaculture Law of Chile, which establishes a 5% increase in extraction quotas following catastrophic events, allowing the extraction of other commercially important species in Tubul to be increased in order to strengthen the local economy (Fisheries and Aquaculture Law Number 20.657, 2013). Finally, despite the substantial physical and environmental disturbances resulting from the tsunami, pelillo extraction exhibited a gradual recovery in 2012, which is supported by recovery of the physical structure of the habitat and the aquatic biota two years after the event in Reference [
39]. However, Aswani et al. [
14] indicated that social recovery was not always concurrent with environmental recovery, which is undoubtedly related to the perception level of the population; possibly, this environmental recovery will influence the recovery of balance in the exploitation of ES in the Tubul-Raqui wetland, as evidenced by Marín et al. [
54].
As previously mentioned, the perceived benefits detected in this study were influenced by the independent categorical variables of gender, age, and ethnicity. However, the main differences were reported regarding gender; for example, the perceived values for hazard regulation services varied strongly, with primarily women recognizing their importance. Possibly, the differences in gender perception may be related to the post-disaster economic effects, which were significantly higher among female gendered persons, who experienced substantial impacts to their labor activities, family incomes and unemployment rate, which reached nearly 31% [
37]. The importance of gender is relevant to perception and has also been recognized in other Mediterranean case studies [
3,
29]. The differences were smaller in the education and economic sector of the sample, most likely due to the rural and socioeconomic homogeneity of the local population; for example, in the case of education, the percentage of inhabitants with college-level studies was minimal, a situation similar to other fishing villages in Chile [
56]. A study of sociocultural valuation done in a nature park in Spain showed that the main characteristics that influenced the valuation were age, place of residence, and education [
28]; however, the level of education in that study was higher than that reported in Tubul. Finally, regarding the age variable, we obtained results similar to those of Oteros-Rozas et al. [
29], with young people having the highest perception of food-related services and older people having the highest perception of the habitat for species services.
Finally, the perception of the ES provision 50 years in the future indicated a proportion of stability and a decrease in services; in the drivers of loss, it was observed that the main causes pointed to anthropogenic factors (contamination and the forestry industry), with natural factors ranked second. According to Zorrilla-Miras et al. [
12], engines of change are generally interrelated. Indeed, in the Mediterranean region of Chile—specifically in the closer coastal area—increases in production and industrial activities, population, and the level of urbanization have been associated with the loss of surface and biodiversity of these kinds of ecosystems [
57,
58,
59]. The spread of exotic species such as
Pinus radiata is a threat to wetlands as it affects native flora and fauna and causes an alteration in ecosystem functions. Furthermore, it has also been shown that
Pinus radiata, with its widespread growth as a monoculture, absorbs a substantial amount of water, therefore decreasing its availability, generating soil changes, and affecting livestock and agricultural activities due to high soil acidity and erosion [
39,
42,
60].
Additionally, natural disasters, as one of the key interests in this study, was the ninth driver of change mentioned by people, despite the scientific community recognizing that the decrease in ES provision (resulting from coseismic uplift of the
MW = 8.8 earthquake), was linked mainly to the loss of pelillo. Future research could address the phenomena related to the time of personal exposure to these drivers. While pollution and the forestry industry have a more prolonged effect, events such as earthquakes and tsunamis have a shorter duration, making it possible that people with a long history in the location understand that these disturbances occur at certain time intervals and that measures to address them must be developed [
13]. This assessment of the perceptions of drivers of loss could be used to manage actions related to conservation, preservation, and the restoration of the system [
61] by considering that the opinion of the population is a fundamental element in the current territorial management instruments.