Perceptions and Social Values Regarding the Ecosystem Services of Beaches and Coastal Dunes in Yucat á n, Mexico

: The ecosystem services (ESs) approach has been used as a powerful tool for the analysis of socio-ecological systems to investigate the relationship between society and the environment. The aim of this article is to analyze the social perceptions of stakeholders, forms of use (sociocultural and economic), and the conservation of beaches and coastal dunes in Yucat á n, Mexico. Interviews were held with focus groups to analyze the forms of use, social perceptions of stakeholders, and the conservation of beaches and coastal dunes in Yucat á n, Mexico. The results indicate that these ecosystems are important to different types of activities related to regulating, provisioning, and cultural services. However, degradation is identiﬁed as a consequence of contamination and land-use change. The main identiﬁed threats are natural phenomena, followed by the presence of garbage, human presence in natural environments, infrastructure construction, and privatization of beaches. The opinions (e.g., conservation, ecosystem services provision, drivers of change), emotions (e.g., joy, fear, sadness), and knowledge of the local community and tourists with respect to these ecosystems were evidenced. In general, there is an absence of conservation and sustainable management projects. However, community perceptions provide an opportunity to outline public conservation strategies in which the community, as a component of these socio-ecosystems, can be fully involved in their implementation.


Introduction
The relationship between human well-being and ecosystem functioning is constantly affected by environmental deterioration, which is mainly related to human activities leading to an imbalance in the provision of ecosystem services (ESs). Ecosystem services are recognized as the human benefits obtained from ecosystems [1,2]. The number of studies that consider the goods and services that ecosystems provide to human societies has increased over the last two decades [3][4][5]; however, there remains a need for strategies that take ESs provision into account in order to achieve a sustainable way of life for human societies and ecosystems [6]. Biophysical and socio-economic characterization is critical for informing decisions concerning the use, management, and administration of ecosystems [7]; however, experience has shown that exclusion of the perception of different stakeholders, along with their ties and interests, can lead to disagreements and even conflicts [8]. Perceptions of ESs depend on the environmental or ecological characteristics of the systems and on the cultural and socio-economic context [9,10]. However, studies have poorly addressed the degree to which ESs are influenced by this context, such as interest in or community perceptions of the relationship between natural ecosystems and human well-being [11,12].
Perceptions guide interactions between people and actions involving the environment, according to their internal and external standards [13]. This feeds back in both directions, allowing people to navigate their social environments [14]. Accuracy is not absolute; it depends on the subject's purpose, goals, emotional experience, interest, and habitual context that appeal to the subject's aesthetic, emotional and active needs [14,15].
Beaches and coastal dunes comprise one of the key coastal environments given their importance at both ecosystem and socio-economic levels [16]. It is recognized that beach and dune ecosystems are important providers of ecosystem goods and services, understood as direct or indirect benefits to society, which can be considered natural capital [17,18]. For example, these habitats constitute a natural protective barrier against hurricanes and high tides [19] because the sedimentation processes that occur within them act to prevent erosion [20]. Coastal dunes provide 28 ESs grouped into four categories, as proposed by the Millennium Ecosystem Assessment [21]-1. provisioning (e.g., medicinal resources), 2. regulating (e.g., erosion prevention and control), 3. cultural (e.g., recreation), and 4. supporting (e.g., soil formation) services [17,22]. In addition to their importance at the ecosystem level, coastal dune systems are of socio-economic value given the tourism and urbanization observed around this environment [23]. However, despite being under constant pressure from anthropogenic and natural disturbances, in Mexico, these systems are not included in any specific protection scheme for their conservation [24]. Of the 808,711 ha of coastal dunes present in the country, it has been estimated that 46% have been transformed by agricultural use or urbanization [25].
Studies examining the beaches and coastal dunes of Mexico have mainly focused on the ecology and vegetation in terms of distribution, interactions, and reproduction (e.g., [26][27][28][29][30][31][32]), revealing important gaps in the knowledge such as outdated inventories of their flora and fauna [24,33]. Research topics that involve the environmental perceptions of the communities focus on the environmental and social impacts of the tourism developed on the beaches of Mexico (e.g., [34][35][36][37]), overlooking the ways of life that arise around the uses and management practices that impact coastal dunes.
In the Yucatán Peninsula, the beaches and coastal dunes are conducive to the development of economic activities of great importance to society in the region, such as local tourism, port activities and services (e.g., maritime trade) and industry (e.g., salt extraction, food processing) [24,38].
Here, we conducted an analysis of the social perceptions and forms of use (sociocultural and economic) of the stakeholders that benefit from ESs of beaches and coastal dunes, as well as their conservation. We interviewed authorities, local communities, and tourists in three ports of Yucatán, due to their close relationships with these ecosystems. The following research questions were posed: What are the main uses (forms of exploitation) that the community makes of the beaches and coastal dunes? What ecosystem services do societies mainly benefit from? Which stakeholders make direct or indirect use of these ecosystems? What is the social perception of the status of conservation of the beaches and coastal dunes? To address these questions, we (1) describe and compare the beach and coastal dune ESs identified by the community across three study sites on the northern coast of Yucatán, (2) explore the most important ESs for the community and how perceptions vary among different stakeholder groups, and (3) describe the most important drivers of the change that impact the conservation of beach and coastal dune systems on the northern coast of Yucatán.

Materials and Methods
This research employed mixed methods, involving techniques for obtaining and analyzing both qualitative and quantitative data. Mixed methods are part of an alternative paradigm to the traditional approach that raises the dilemma of qualitative versus quantitative analysis, using techniques from both methods that are adapted to the research question and to the characteristics of the participants [39]. The qualitative analysis of the study provides an understanding and interpretation of the perceptions and opinions of the involved stakeholders regarding their relationship with the environment. The quantitative analysis was incorporated in order to obtain results by inferential statistical analysis that allows generalization through a hypothesis tested evaluation [40]. The methodological design model used was the concurrent triangulation strategy [39]. We obtained quantitative and qualitative information in fieldwork conducted in the same collection period, using semi-structured interviews, qualitative observations, and surveys. From this model, analysis of the qualitative and quantitative data is carried out in parallel. We began with the transcription of the interviews and, at the same time, a database was produced with the data from the survey to enable comparison of the results among communities and also provide explanatory data related to descriptive statistics. In Section 2.3, we will explain in detail how the analysis was performed.

Study Site
The state of Yucatán has 13 municipalities that occupy 378 km of coastline, from Celestún in the west to El Cuyo in the east [41]. In this region, there are 12 seaports supporting activities such as tourism, commerce, and fishing [41]. The beaches in the area present a low slope towards the sea and have submarine or visible sandbanks, making maritime navigation by deep-draft vessels difficult [41]. Some areas present a communal form of land tenure, known as the ejido system, which comprises rural properties under collective use.
A multiple case study was developed in three coastal communities in the central portion of the state of Yucatán-the ports of Sisal, Chuburná, and Telchac ( Figure 1). These communities were chosen for their proximity to the city of Mérida, as the most urbanized area in the region, with frequent movement of people to and from the study sites as traditional recreational ports for the population. This research employed mixed methods, involving techniques for obtaining and analyzing both qualitative and quantitative data. Mixed methods are part of an alternative paradigm to the traditional approach that raises the dilemma of qualitative versus quantitative analysis, using techniques from both methods that are adapted to the research question and to the characteristics of the participants [39]. The qualitative analysis of the study provides an understanding and interpretation of the perceptions and opinions of the involved stakeholders regarding their relationship with the environment. The quantitative analysis was incorporated in order to obtain results by inferential statistical analysis that allows generalization through a hypothesis tested evaluation [40]. The methodological design model used was the concurrent triangulation strategy [39]. We obtained quantitative and qualitative information in fieldwork conducted in the same collection period, using semi-structured interviews, qualitative observations, and surveys. From this model, analysis of the qualitative and quantitative data is carried out in parallel. We began with the transcription of the interviews and, at the same time, a database was produced with the data from the survey to enable comparison of the results among communities and also provide explanatory data related to descriptive statistics. In Section 2.3, we will explain in detail how the analysis was performed.

Study Site
The state of Yucatán has 13 municipalities that occupy 378 km of coastline, from Celestún in the west to El Cuyo in the east [41]. In this region, there are 12 seaports supporting activities such as tourism, commerce, and fishing [41]. The beaches in the area present a low slope towards the sea and have submarine or visible sandbanks, making maritime navigation by deep-draft vessels difficult [41]. Some areas present a communal form of land tenure, known as the ejido system, which comprises rural properties under collective use.
A multiple case study was developed in three coastal communities in the central portion of the state of Yucatán-the ports of Sisal, Chuburná, and Telchac ( Figure 1). These communities were chosen for their proximity to the city of Mérida, as the most urbanized area in the region, with frequent movement of people to and from the study sites as traditional recreational ports for the population. The port of Sisal is 53 km from the state capital of Yucatán (Mérida). Since the 19th century, it has been considered a small port for the extraction of commercially important The port of Sisal is 53 km from the state capital of Yucatán (Mérida). Since the 19th century, it has been considered a small port for the extraction of commercially important marine species [42]. Economic activities have ranged from duck hunting [43], salt extraction, and agriculture to ecotourism activities such as boat rides for bird watching (e.g., pink flamingo), visits to the Petenes and mangroves, and scuba diving [44,45].
The port of Chuburná is 56 km from Mérida. It is characterized by a severe beach erosion problem [46,47], for which mitigation was sought through the construction of two protective piers. In the past, this port was an important supplier of fish to Mérida. Currently, tourism and recreational fishing have become more popular in the locality [41]. Chuburná has a large number of summer vacation homes and the population size triples during the holiday season [45,48]. However, the traditional economic activities practiced throughout the year are related to fishing for local consumption [49].
The port of Telchac is located 69 km from Mérida. It was considered an important center for the production and commerce of henequén (a plant fiber chiefly used for twine) [50]. Currently, it presents a considerable level of "sun and beach" type touristic activity [51]. Nevertheless, the majority of the population continues to work in the primary sector, which is mainly fishing for commercial and local consumption [52].

Data Collection
Semi-structured interviews were conducted, based on a format that combined open and closed questions, allowing for a guided and systematic conversation [53]. Those involved were organized into three groups to obtain information on how they perceive, use, and manage the beaches and coastal dunes. These groups were defined as (1) authorities, i.e., representatives of various governmental and non-governmental organizations, with the power, capacity, and/or means to decide and influence the use and management of the coastal dunes at different levels of intervention (state, municipal and local), (2) local communities, i.e., inhabitants of each study site, and 3) tourists, i.e., those who not live in the study site but visit the area for short periods of time.
The informants in each group were selected using the intentional sampling technique of the qualitative methodology [54], in which participants were chosen based on criteria or characteristics that must be met according to the objective of the research and their relevance for providing information. The criteria for the informants were (a) to have an active socio-ecological role in the dunes and beaches that allows them to explain the ecosystem services provided by these ecosystems, their uses and conservation, and (b) availability to participate in the study. The ethnographic technique of opportunity interviews was used to approach local community informants and the group of tourists while they were on vacation or engaged in daily activities on the beaches or other locations in the studied communities. The fieldwork also considered the dates which are known to have the greatest influx of tourists in the study area.
In addition to interviews, we used the technique of observation, which consists of a systematic approach to assess the behavior of the subjects of study in a given space, in order to understand their forms of interaction [55]. For the present study, we carried out an observation record that allowed us to capture the behavior and activities of tourists, focusing on particular aspects of the ways in which ecosystems are used. The observers interacted with the tourists when the opportunity arose to conduct interviews. The observation was conducted on average for 15-20 min, while the subjects analyzed were on hand. The information obtained through observation allowed researchers to contrast and complement that obtained in the interviews in order to achieve a greater validity and reliability of the results obtained [54].
The interview questionnaires and the observation record included the following sections: (1) community perception and its relationship to the beaches and coastal dunes, (2) relevant activities carried out on the beaches and coastal dunes, and (3) perception of the state of conservation and threats to these ecosystems ( Table 1). The interview questionnaires included questions that sought to capture personal opinion on the recognition, importance, form of uses, and valuation of coastal dunes, questions on the identification of conservation activities, and questions on the problems that threaten conservation. The information related to conservation used illustrative images to visually identify the degree of conservation/erosion, thus facilitating the acquisition of answers. Demographic questions were also asked to characterize the informants who participated in the study. The classification of ecosystem services, based on the Millennium Ecosystem Assessment (MEA), was included as response options on the use of dunes (support, provision, regulation, and cultural services) [21]. However, responses beyond this framework were also recorded and analyzed.
The interviews had two different formats (open questions for authorities and local communities and closed questions for tourists), which reflected the particularities and dynamics of each group involved. The questions addressed to the authorities and to the local community were designed in an open format, which sought to record their experience in relation to the ecosystem and its stability over time. In the case of the tourists, the questions were of a closed format in order to minimize the time taken for each interview and to obtain concrete and specific answers about their activities, since their visits are typically of short duration and they cannot perceive medium-or long-term changes in the ecosystem.
During the months of March 2019 and April 2019, a total of 139 semi-structured interviews were applied, considering 24 authorities, 60 local inhabitants, and 55 tourists (supplementary material). The total sample of the interviews was determined based on the criterion of theoretical saturation, i.e., the moment in which understanding of the central concept of the study had already been achieved (the ecosystem services from the MEA approach). The average duration of these conversations was 30 min for authorities and local communities and 10 min for tourists. All interviews were recorded for subsequent analysis.

Data Analysis
To analyze the information obtained through the semi-structured interviews and observations, we used content analysis based on Krippendorff [56] and Merriam [57]. The following steps were taken:

•
Transcription of participant interview responses in Microsoft Word. The observation notes were analyzed directly from the original record, considering the same criteria of comparison as the interviews; • Selection of two or more comparative sample texts. Compared texts were transcriptions of interviews and notes from observations; • Classification of the comparative sample text considering the stakeholder typeauthority, local community, and tourist. This was conducted in order to establish units of analysis; • Definition of semantic or grammatical categories in every fragment, i.e., we classified the content or central idea of every unit of analysis according to the concepts and classification defined by the Millennium Ecosystems Assessment [14]. To classify the stakeholders' interview responses, several readings of the transcribed material were conducted. We also identified other categories outside the MEA classification, expanding our understanding of the stakeholder's perception of ecosystem services; • From the categories, we calculated the percentage frequency and produced tables to help individualize the relationships among the stakeholder responses. For this purpose, a numerical coding system was created to quantify the qualitative data and record their frequency. IBM's Statistical Package for the Social Sciences (IBM SPSS) Version 23 was used to systematically organize the information in 17 categories in order to identify response trends in the topics explored ( Table 1). The emerging categories are considered quantitative categorical variables. With this information, a descriptive analysis of frequencies was carried out [58,59] (p. 187) indicating that "the most critical outcome of qualitative data analysis is to interpret how the individual components of the study weave together. Codeweaving is the actual integration of key code words and phrases into narrative form to see how the puzzle pieces fit together." Thus, in the process of analyzing the qualitative data, the presentation of descriptive statistics is a strategy by which to find patterns and themes in the entire pool of information provided by stakeholders [39].

•
The narrative and explanation of the patterns of responses were described in order to jointly present the opinions of the stakeholder participants of the study. These also allowed conclusions to be drawn based on the focus and theoretical frame of the study; • The categories were described and examples or quotes from stakeholders were identified. These were contrasted and compared with the literature in order to define the main significance of the stakeholder's statements [60]. Finally, hypothetical scenario questions from section three (e.g., what do you think would happen if the coastal dunes were to disappear?) were recorded in order to generate a "word cloud" scheme that displays the frequency and diversity of opinions expressed in response to the question posed [61].
For the quantitative analysis, we compared answers using nonparametric statistics. For considering ESs types identified according to demographic characteristics (age and sex) a Fisher's exact test for count data was performed. We then compared stakeholder's responses regarding perceptions of the ESs provided, human activities, conservation status, and changes in beach and coastal dunes using an exact multinomial test. The null hypothesis was that all proportions of the counts (using counts as the test input) will be equal. This approach performs a goodness-of-fit-test for discrete data [62]. When significant differences were found, a binomial exact test was performed, in which pairs of categories were evaluated. In these comparative analyses, we focused on determining whether the most frequent answer was in the same proportion as the rest (one by one). The p-values for post hoc comparisons were adjusted using the Holm method [63].

Social Sampling Description
The sex ratio of the interviewed stakeholders was similar between men and women-49% and 51%, respectively. With respect to age, the highest percentage (27%) was between 35 and 44 years old and the highest number of stakeholder participants was from the local community group (43%), followed by tourists (40%), and finally the authorities (17%) ( Table 2). There was a diverse classification of authorities according to their functions and the institution to which they belong ( Table 2). The "political-institutional group" refers to people linked to the government and related to a position of public administration (e.g., municipal commissioners). The term "local leaders" refer to those people who are recognized within the locality for their experience in working with the community. "Nongovernmental organizations (NGOs)" and "economic organizations" are structured groups that carry out productive activities or provide services that generate an economic benefit in the community, (e.g., fishing and tourist cooperatives and coastal ejidos). The number of interviewees at each study site was similar between locations ( Figure 2).
Sustainability 2021, 13, x FOR PEER REVIEW 7 of 23 municipal commissioners). The term "local leaders" refer to those people who are recognized within the locality for their experience in working with the community. "Non-governmental organizations (NGOs)" and "economic organizations" are structured groups that carry out productive activities or provide services that generate an economic benefit in the community, (e.g., fishing and tourist cooperatives and coastal ejidos). The number of interviewees at each study site was similar between locations ( Figure  2).

Community Perception and Its Relationship to the Beaches and Coastal Dunes
The stakeholders revealed enriching, profound, and extensive information about the knowledge of perceived ecosystem services of beaches and coastal dunes. The users are presented below.

Direct and Indirect Users of Beaches and Coastal Dunes
Two main user groups of these ecosystems were identified. A. Direct Users (a) Local communities-provide independent tourist services on the beaches and coastal dunes, such as rental of palm-roofed shelters, sale of food, and handicrafts. They also carry out beach cleaning as part of temporary work provided by the government during weather unsuitable for fishing. In general, the group does not use the ecosystem for recreational purposes, as reflected in the following quote:

Community Perception and Its Relationship to the Beaches and Coastal Dunes
The stakeholders revealed enriching, profound, and extensive information about the knowledge of perceived ecosystem services of beaches and coastal dunes. The users are presented below.

Direct and Indirect Users of Beaches and Coastal Dunes
Two main user groups of these ecosystems were identified. A. Direct Users (a) Local communities-provide independent tourist services on the beaches and coastal dunes, such as rental of palm-roofed shelters, sale of food, and handicrafts. They also carry out beach cleaning as part of temporary work provided by the government during weather unsuitable for fishing. In general, the group does not use the ecosystem for recreational purposes, as reflected in the following quote: "No, tourist come to swim and enjoy the beach [use it] because the truth is that we don't, we don't use them."-Local community, Sisal.
Representatives of fishing cooperatives were included in the interviews. However, fishermen were not identified as users of the beach and coastal dunes due to the presence of a sheltered harbor in each community where they access the fishing grounds and conduct activities (e.g., boat storage and maintenance, waste disposal). Fishermen mainly carry out their activities offshore and are dependent on the availability of marine species. On the other hand, despite the fact that some stakeholders were part of the ejido of the study areas, none of the participants mentioned activities or processes carried out by the ejidatarios that influence the social or environmental dynamics that occur on beaches and coastal dunes; (b) Tourists-people that perform a recreational use of the beaches and coastal dunes. These ecosystems mainly receive local tourists from the city of Mérida or nearby towns over short periods of time. On day trips, the beach is the location where they spread towels or set up umbrellas for protection from the sun. They usually buy food from local vendors or bring their own and bathe in the sea. Some use the dunes for cover while changing their wet clothes.
B. Indirect Users (a) Non-governmental organizations, legally established and comprising both permanent and temporary residents-these groups engage with the local community through participatory activities (e.g., environmental education, computing, English classes, etc.). During the summer of 2019, we participated with one of these institutions and implemented an environmental education workshop with primary school children and their teachers in order to promote knowledge of the ESs of the coastal dunes and their conservation. We carried out educational activities on the beach and observed that while the children enjoyed playing there, many of them and their teachers were unaware of the ESs that the dunes provide. This workshop was part of the activities organized by this association in a summer camp for local children; (b) Local institutions and organizations-groups that conduct economic activities that have an impact on the beaches and coastal dunes. They have a direct relationship with the local community (e.g., tourist and fishing cooperatives) and mostly comprise people from the municipalities; (c) Municipal, state, and federal authorities-those who work in coordination with groups and authorities at different levels of government in order to manage natural resources. Some have implemented and promoted restoration programs for beaches and coastal dunes. They regulate and monitor actions aimed at port and navigation activities (e.g., permits and concessions for the use of federal areas).

Perceptions of Goods and Ecosystem Services of Beaches and Coastal Dunes
The comparison considering demographic characteristics did not show significant differences in any of the study sites according to sex (Fisher's exact test for count data, Sisal p = 0.8846; Chuburná p = 0.8677; and Telchac p = 0.7912) or age (Fisher's exact test for count data, Sisal p = 0.4426; Chuburná p = 0.8725; and Telchac p = 0.8756).
In general, 46% of the stakeholders reported no knowledge of the coastal dunes concept. However, when a photograph of this habitat type was shown to them, 62% recognized it. Local people and tourists defined coastal dunes as a natural space, where mounds of sand occur near the beach and that may or may not have vegetation. The following quotes exemplify some definitions of the coastal dunes given by interviewees: "They are the vegetation and the dune is the promontory of sand, the natural part of the coast."-Tourist, Telchac Puerto.
A total of 35% of stakeholders in Sisal and Chuburná and 45% in Telchac reported no knowledge of the coastal dunes concept. In this case, some people use the concept of "coastal" to refer to "dunes," as shown by the following quote: "We call dunes what is the mangrove, the estuary, all that, these are the coastal," (points to the photos of coastal dunes)-Authority, Telchac Puerto.
The local communities responded that they did not know what a coastal dune is because this term is not the same as the one they use to refer to this ecosystem. This result has important implications for communication and environmental education. For the educational process to develop effectively, it is fundamental to communicate with the same local terms.
In all study sites, 91% of stakeholders expressed the opinion that beaches and coastal dunes are natural areas to which they have an emotional attachment. They perceive them as quiet, beautiful, and natural places where they can rest. The authorities recognize that coastal dunes are important natural areas within their scope, such as monitoring the care of the beaches, as well as for the local community to promote tourist activities in the natural environment.
In each study site, the stakeholders identified a great diversity of goods and services provided by the coastal dunes (Table 3). For authorities, the regulating services were the most important, followed by provisioning and cultural services (p < 0.0001). For local inhabitants, provisioning, regulating, and cultural services were important in that order (p < 0.001). For tourists, cultural and regulating services were the most important in that order (p < 0.0001). In all of the study sites, regulatory services were those most commonly identified, followed by cultural and provision services. In Sisal and Chuburná, provision services showed significant differences to those of Telchac (p < 0.01). No other significant differences were observed (Figure 3). Regulatory services were mainly related to protection against extreme weather events such as hurricanes, storms, northerly weather fronts known locally as "nortes" and floods as expressed in the following quote: "When Hurricane Gilberto occurred, the dune saved us, if there were no dunes there would be more erosion on the beach; I have observed that the plants' roots lift the earth and form the dunes, the plants make the dunes and not the other way around as they say" (sic)-Local community, Sisal.
habitants, provisioning, regulating, and cultural services were important in that order (p < 0.001). For tourists, cultural and regulating services were the most important in that order (p < 0.0001).
In all of the study sites, regulatory services were those most commonly identified, followed by cultural and provision services. In Sisal and Chuburná, provision services showed significant differences to those of Telchac (p < 0.01). No other significant differences were observed (Figure 3). Regulatory services were mainly related to protection against extreme weather events such as hurricanes, storms, northerly weather fronts known locally as "nortes" and floods as expressed in the following quote: "When Hurricane Gilberto occurred, the dune saved us, if there were no dunes there would be more erosion on the beach; I have observed that the plants' roots lift the earth and form the dunes, the plants make the dunes and not the other way around as they say" (sic)-Local community, Sisal.  The main natural threats to the three ports are the "nortes" and hurricanes. When hurricanes occur, the inhabitants must leave their homes and businesses to go to a temporary shelter or to the home of a relative in the nearest town. They can lose belongings and animals. It is encouraging to know that, for many people, dunes bring protection against these natural phenomena and this could be of great help to their conservation. However, several people do not know that the coastal dunes provided this type of ESs, which represents a risk to its conservation. With respect to provisioning services, these were mainly related to the medicinal use of native plants that grow in the coastal dunes. Species, such as Ipomoea pes-caprae (commonly known as "riñonina," a Spanish word related to the kidney) and Cordia sebestena (commonly known as "anacahuita") were mentioned, along with the consumption of animal products such as turtle eggs: ". . . it is parboiled, and the water is drunk, it is very good for kidneys ( . . . ) [about the anacahuite tree] . . . it is good for burns, it is like iodex . . . "-Authority, Sisal.
". . . In ancient times, we ate the turtle eggs that were left in dunes, to cure asthma . . . "-Local community, Chuburná.
During our field trips across the beaches and dunes, we could detect the smell of honey from a plant commonly known as "mielera" (honey). This plant is frequently visited by pollinators and is generally valued and conserved in the communities for this smell. Locals expressed their interest in learning more about the coastal dune plants for restoration and ornamental purposes. Some stakeholders made more profound responses and some of their observations went beyond the MEA categories. These perceptions were considered outside this conceptual framework. For instance, the categorization "other" in Table 3 corresponds to responses that consider ecosystems as garbage dumps, toilets, or shelter sites. The local inhabitant group provided responses outside of the MEA classification that were nevertheless important to them (p < 0.001) ( Table 3). Furthermore, in Telchac and Sisal, ecosystem disservices were recognized, including garbage dumps, toilets, and shelter sites. Some stakeholders refer that tourists and some locals take advantage of the dunes to dump their garbage and that this is a negative aspect of the zone.

Perceptions of Conservation Status and Threats of Beaches and Coastal Dunes
Opinions regarding conservation status are contrasting among sites and stakeholders ( Figure 4). In Sisal, stakeholders consider that beaches and coastal dunes are in regular to good condition (p < 0.001). In Chuburná, the responses did not show significant differences between the conservation status perceptions; however, regular status had the highest number of responses. In Telchac, stakeholders perceived these ecosystems to be in poor to regular condition (p < 0.01). These conditions consider little vegetation, visible spaces without vegetation, and some degree of erosion, depending on a specific area. In Chuburná, the eastern end and central part of the town's coastline are completely eroded, and beaches and coastal dunes have been entirely lost there. At the western end of the town, there is a very extensive section of beach and coastal dunes formed by accretion processes. One of the stakeholders in Chuburná explained that in the past she could go for a walk on the beach, but that she can no longer enjoy this because there are no more beaches. She mentioned that tourists will probably no longer come to the port and that would bring adverse economic effects in the community.

Perceptions of Conservation Status and Threats of Beaches and Coastal Dunes
Opinions regarding conservation status are contrasting among sites and stakeholders ( Figure 4). In Sisal, stakeholders consider that beaches and coastal dunes are in regular to good condition (p < 0.001). In Chuburná, the responses did not show significant differences between the conservation status perceptions; however, regular status had the highest number of responses. In Telchac, stakeholders perceived these ecosystems to be in poor to regular condition (p < 0.01). These conditions consider little vegetation, visible spaces without vegetation, and some degree of erosion, depending on a specific area. In Chuburná, the eastern end and central part of the town's coastline are completely eroded, and beaches and coastal dunes have been entirely lost there. At the western end of the town, there is a very extensive section of beach and coastal dunes formed by accretion processes. One of the stakeholders in Chuburná explained that in the past she could go for a walk on the beach, but that she can no longer enjoy this because there are no more beaches. She mentioned that tourists will probably no longer come to the port and that would bring adverse economic effects in the community.

Drivers of Change That Affect the Ecosystems and Provision of Their ESs
Most stakeholders observed that the coastal dunes have changed over time ( Figure  5). In general, 73% of stakeholders perceive negative and 17% positive transformations in the dunes. In Sisal, there were no significant differences between positive and negative transformations (p = 0.5154). However, in Chuburná and Telchac significant differences (p < 0.0001) were observed. The most important change in Sisal was the presence of more vegetation and beach area (p < 0.01), as shown by the following quote:

Drivers of Change That Affect the Ecosystems and Provision of Their ESs
Most stakeholders observed that the coastal dunes have changed over time ( Figure 5). In general, 73% of stakeholders perceive negative and 17% positive transformations in the dunes. In Sisal, there were no significant differences between positive and negative transformations (p = 0.5154). However, in Chuburná and Telchac significant differences (p < 0.0001) were observed. The most important change in Sisal was the presence of more vegetation and beach area (p < 0.01), as shown by the following quote: ". . . they are more lush and with more vegetation [coastal dunes] . . ."-Authority, Sisal.
In Chuburná, the stakeholders perceived that dunes have been lost, and in Telchac, most of them observed that the coastal dunes are more contaminated (p < 0.01). They also considered that the dunes have lost height and indicated that the coast has eroded ( Figure 5). This is reflected in the following quote: ". . . The sea has come closer to the town . . ."-Authority, Sisal. In Chuburná, the stakeholders perceived that dunes have been lost, and in Telchac, most of them observed that the coastal dunes are more contaminated (p < 0.01). They also considered that the dunes have lost height and indicated that the coast has eroded ( Figure  5). This is reflected in the following quote: ". . . The sea has come closer to the town . . ."-Authority, Sisal. We observed that, in some areas of Chuburná and Telchac, the first row of houses is already destroyed or very eroded by the sea (Figure 6a,b). We also observed very recent constructions or work in progress very close to the coastline (Figure 6c,d). The principal changes discussed in the scientific literature that support people´s perceptions regarding changes and deterioration of the coastline are addressed in the discussion section. We observed that, in some areas of Chuburná and Telchac, the first row of houses is already destroyed or very eroded by the sea (Figure 6a,b). We also observed very recent constructions or work in progress very close to the coastline (Figure 6c,d). The principal changes discussed in the scientific literature that support people s perceptions regarding changes and deterioration of the coastline are addressed in the discussion section. Main changes have been related to different drivers of which the most commonly identified by stakeholders were natural phenomena (hurricanes Gilberto in 1988 and Isidoro in 2002, tides, natural erosion processes, red tides, nortes, etc.). Both of these hurricanes remain in the memory of the community as a consequence of their devastating impact on the region. The community members report that they have not been affected by another hurricane of that magnitude. The drivers of change were mainly perceived in Chuburná (Table 4) Main changes have been related to different drivers of which the most commonly identified by stakeholders were natural phenomena (hurricanes Gilberto in 1988 and Isidoro in 2002, tides, natural erosion processes, red tides, nortes, etc.). Both of these hurricanes remain in the memory of the community as a consequence of their devastating impact on the region. The community members report that they have not been affected by another hurricane of that magnitude. The drivers of change were mainly perceived in Chuburná (Table 4). Constructions and concessions on the beach for commercial or recreational use (rental of palm-roofed shelters, selling handicrafts, and federal concessions on the beach) were identified as a second source of change (Table 4). Another important driver of deterioration, according to stakeholders, was the construction of the high-altitude port of Progreso that presents a large dredging draft infrastructure (7.5 km offshore), blocking sand transportation by the currents. According to the stakeholders, this has reduced the length of the beach and the coastal dunes. This driver of change is predominant in Chuburná (14%), which is the closest study area to the port of Progreso (Table 4). Stakeholders also considered the clearance of vegetation to gain access to the beach and for construction purposes to be a driver of change, as indicated in the following quote: ". . . tourists come and deforest the dune, they clear the beach to extend their blanket or to avoid tripping over the vines . . ."-Local community, Chuburná.
Stakeholders mentioned that the structures and activities that have been established to prevent erosion and recover the beach extension (Table 4), such as spurs, breakwaters, dikes, and beach fillings (with the transfer of sand), have contributed to greater erosion and loss of coastal dune vegetation. This was particularly observed in Chuburná (11%), and to a lesser extent in Sisal and Telchac, as mentioned in the following quote: ". . . the currents and the tides together with the built structures have changed everything in the retention of sand."-Authority, Chuburná.
In Telchac, the results indicate that the lack of environmental education, and thus the lack of knowledge regarding the care of the coastal dunes, is an important driver of change that exacerbates the deterioration of these ecosystems. The use of motorized vehicles (motorcycles, scooters, and cars) on beaches and coastal dunes was an important cause of degradation (Table 4). This is related to the opening of new gaps between the coastal dunes, which act to impede their growth. In Sisal, this activity was recorded with a greater perception (11%). This is in contrast to Chuburná, where the stakeholders did not perceive this phenomenon. However, during field observations, a large number of vehicles were observed on the beach of Chuburná, where degradation of the coastal dune vegetation as a result of this driver of change was observed. Local stakeholders (mostly the local community and tourists) perceive an inefficiency of the authorities (at different levels) in terms of carrying out successful activities and projects to protect and conserve these ecosystems (Table 4). In the section "others" of Table 4, the responses were grouped regarding the sale of sand for construction, for playgrounds, or to fill the beach elsewhere. There are also activities perceived on beaches and coastal dunes that are associated with fishing and the use of horses.
Regarding the main threats that can impact coastal communities, the stakeholder's responses were grouped into three types that differed statistically at the three sites (p < 0.0001)-natural, natural processes intensified by human actions, and anthropogenic ( Figure 7). Stakeholders identified natural phenomena (hurricanes, floods, nortes, and storms) as the main threat (87%) that can negatively affect them, as indicated in the following quote: ". . . Cyclones affect us more, if another [hurricane] hits we disappear, because everything thrown [sic] . . ."-Local inhabitant, Chuburná.
In addition, sargassum spp., climate change, and erosion were identified as natural processes intensified by human action in Sisal (5%), and Telchac (2%). However, this type of response was not indicated in Chuburná. "Garbage" is considered a significant anthropogenic threat identified in the three communities (p < 0.001). "Presence of humans in ecosystems" is also one that is characteristic of major impact and was frequently mentioned (p < 0.001), without emphasizing any particular activity. Construction on the beach is an activity that, in addition to being identified as a driver of change, was also identified as a threat being significant in Chuburná (p < 0.001) (Figure 7).

Community Perception in a Catastrophic Conservation Scenario
A word cloud diagram (Figure 8) was generated from the frequency of words used by stakeholders in their responses to questions regarding a hypothetical natural environment without coastal dunes and beaches. The diagram shows the emblematic responses (according to the size of each word). An emotional component, mainly classifying the loss of these ecosystems as "painful," "tragic," and "catastrophic," was observed. The stakeholders recognized that they would be more vulnerable to floods, erosion, and rising temperatures without the protection of the coastal dunes. This situation would lead to consequences such as decreased tourism that would affect their income, increasing unemployment and prompting further population migration in order to find better opportunities elsewhere.

Community Perception in a Catastrophic Conservation Scenario
A word cloud diagram (Figure 8) was generated from the frequency of words used by stakeholders in their responses to questions regarding a hypothetical natural environment without coastal dunes and beaches. The diagram shows the emblematic responses (according to the size of each word). An emotional component, mainly classifying the loss of these ecosystems as "painful," "tragic," and "catastrophic," was observed. The stakeholders recognized that they would be more vulnerable to floods, erosion, and rising temperatures without the protection of the coastal dunes. This situation would lead to consequences such as decreased tourism that would affect their income, increasing unemployment and prompting further population migration in order to find better opportunities elsewhere.
A word cloud diagram (Figure 8) was generated from the frequency of words used by stakeholders in their responses to questions regarding a hypothetical natural environment without coastal dunes and beaches. The diagram shows the emblematic responses (according to the size of each word). An emotional component, mainly classifying the loss of these ecosystems as "painful," "tragic," and "catastrophic," was observed. The stakeholders recognized that they would be more vulnerable to floods, erosion, and rising temperatures without the protection of the coastal dunes. This situation would lead to consequences such as decreased tourism that would affect their income, increasing unemployment and prompting further population migration in order to find better opportunities elsewhere. Figure 8. Word cloud, in response to the hypothetical scenario that beach and coastal dunes were lost.

Discussion
Our study focused on analyzing the social perception of the stakeholders and the forms of use (sociocultural and economic) of the ESs, and conservation of beaches and coastal dunes in Yucatán.
Coastal dunes are not clearly recognized for the range of ESs they provide. Everard et al. [17], in a study of coastal dunes of the UK, considered that social perception underestimates and neglects these ecosystems despite recognizing 28 ESs described in the Millennium Ecosystem Assessment (2005). Our results indicate that the community perception of the ESs provided by beaches and coastal dunes comprises regulating services (28%), followed by cultural (26%), provisioning (23%), and finally supporting (10%) services. Control of extreme events and climate regulation were the services best identified by the stakeholders as regulatory services, followed by recreation and the beauty of the landscape as cultural services. This result coincides with the findings of Rojas et al. [64], in which cultural and regulating services for coastal wetlands are more important than provisioning services, especially following natural disasters such as tsunamis and floods. These authors found that the community also considered supporting services, such as habitat for the species. To some extent, this coincides with our results. Supporting services were the least mentioned by stakeholders and were mainly related to the maintenance of wildlife. It is important, through environmental education, to strengthen the knowledge of the stakeholders regarding supporting services. By providing a literature review, Rodriguez-Revelo et al. [22] documented that the services of refuge from supporting and cognitive development from cultural services are the most important in the Baja California Peninsula. These findings contrast with our study because the perception of stakeholders seems supporting services as the less important. However, cultural services are of great importance in both of the peninsulas in Mexico.
Cultural services through recreational use are very consistent in the perception of the different stakeholders at each site. Tourism and other activities related to the appreciation of the aesthetic beauty of the landscape are very important in each locality. Similar results were found by Quintas-Soriano et al. [12], who analyzed four socio-ecosystems in different geographical and cultural contexts. The authors observed that cultural services were considered as primary benefits for human well-being that should be protected. The use of cultural services requires a deeper analysis to understand the trade-offs that might arise from the use of regulating, provisioning, and supporting services. Our observations showed that tourists and temporary residents value their proximity to the ocean but at the same time put their properties at risk and generate conflicts with local people who try to stop this type of construction. In several cases, the development of tourist infrastructure acts to deteriorate ecosystems, thus altering the provision of other services.
Regarding the conservation of the ecosystem and the most important drivers of change, perceptions contrast among the study sites. Some authors have assessed coastal changes on the northern coast of the Yucatán peninsula. For example, Appendini et al. [65] characterized coastal areas (including our study area) that are stable or where erosion and accretion processes occur. From Sisal to Chuburná, an important sediment transport gradient is found, resulting in a very dynamic system in which eroded areas occur frequently. Nevertheless, in Sisal, the status of conservation of beaches and coastal dunes is perceived by the stakeholders to be from regular to good. However, the status considered by those of Chuburná and Telchac tends to be from poor to regular. In the same study, Appendini et al. [65] found that the coastal area between Chuburná and Telchac is the most eroded in Yucatán (beach property is damaged as shown in photos of dunes in a poor conservation state in local community and authority interviews; photo in questions 7 and 8 of authorities and local community interviews in supplementary material and Figure 5). These coastal changes seem to be related to the greatest presence of urbanization and several human interventions, such as shelter ports, a high-altitude port offshore construction, harbor structures that interrupt the sediment supply leading to high erosion rates, and construction of housing that has destroyed the dune systems [65,66]. These results coincide with the perceptions of the interviewees that also add hurricanes as a factor of change. Meyer-Arendt [67] provided a historical settlement description on the northern Yucatán coastline that shows evidence of erosion processes, despite long stretches of coastline that were expected to be stable [65]. At present, erosion is exacerbated by landowners building unauthorized groins and breakwaters as a mitigation measure against beach erosion, which in fact lead to a chain of erosion events [66,68]. The main changes in stakeholder opinion are linked to processes of pollution, fragmentation, and beach erosion. Such processes are mainly generated by human presence, which coincides with Rojas et al. [64] in wetland ecosystems, where anthropogenic activities were found to be the most important drivers of change affecting the provision of ESs.

Ecosystem Disservice Perspectives
The different services provided by an ecosystem that have a positive impact on human well-being are related to the perception of the different stakeholders. This could be contradictory since some stakeholders perceive benefits from ecosystems, where others can perceive the same as problems [69]. In our study, 13% of responses did not fit within the conceptual framework of the MEA but were linked to other types of uses (garbage dumps, toilets, or shelter sites) or were instead described as ecosystem disservices (EDSs). However, the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) framework presents another approach that uses the notion of nature's contributions to people (NCPs) [70,71], which are defined as the positive benefits-and occasionally losses, detriments, or negative contributions-that people obtain from ecosystems. This resonates with the original use of the term ESs by the MEA framework and defines other knowledge systems and worldviews on human-nature relations [72]. These EDSs or negative NCPs are linked to ecosystem properties that are perceived as having negative effects on human well-being [73][74][75]. Von Döhren and Hasse [69] stated that these concepts have generally not been addressed. In our study, these were linked to the perception of spaces in the coastal dunes that, with inadequate or no management, can accumulate garbage, affect human health through the proliferation and spread of harmful animals or disease vectors, and affect the aesthetic beauty of the landscape or access to the beach. This is related mainly to the presence of vegetation, which by its nature can cause injury to visitors and tourists (particularly plants with thorns or dry branches). In addition, the human influence on the ecosystem is recognized as part of the formation of the EDSs or negative NCPs (e.g., coastal areas with the accumulation of garbage carried by sea or directly deposited on the coastal dunes that have no public or private maintenance).
Torres-Freyermuth et al. [68] investigated beach morphodynamics in the northern Yucatán peninsula using beach surveys and unmanned aerial vehicle flights. The authors observed that sea breezes play an important role in nearshore hydrodynamics and sediment transport. Therefore, low impact infrastructure should be installed in order to gain access to the beach (e.g., the use of elevated wooden walkways that can allow sediment movement and the maintenance of native vegetation), rather than creating open spaces with bare sand in large areas of a deteriorated landscape. Deterioration of the dune landscape, beach erosion, and the removal of the primary dune due to growth of the coastal urban area might cause environmental and economic impacts on the coast, particularly in low-lying coastal areas such as our study sites. These areas are vulnerable to climate change impacts, such as the sea-level rise and storm activity.

Outline of Public Conservation Strategies for the Use and Management of Beaches and Coastal Dunes
Considering the different cultural and socio-economic contexts involved in the use and exploitation of ecosystems in different regions [12], the information generated in this study can contribute to the design of strategies and public policies for the sustainable management of beaches and coastal dunes in the state of Yucatán. This information can serve as a baseline from which to understand the identification and dependence that local communities have, with respect to ESs. Furthermore, it might help to identify the concepts most important to them and link those to decisions being made regarding the use of the ecosystems. Elwell et al. [76] used the perceptions of different coastal communities regarding the most important ESs identified in southeastern Chile as a guide to focus efforts on proposed models and options for ecosystem management under different contexts. These authors found 17 different types of wetland ESs on which users depend, according to different communities interviewed, including direct and indirect users, and others who do not depend on the resource. They consistently found that cultural services, such as the aesthetic beauty of the landscape, are perceived by different stakeholders as being very important for human well-being. Understanding user perceptions in their own words and from their reference frames could facilitate such assessment. According to the perceptions of stakeholders, the local use and exploitation of the community is highlighted and thus participation of their actions in the administration and management of ecosystems in each community can be promoted. In our three study sites, regulating, provisioning, and cultural services were the categories considered to have been perceived to the greatest extent. This reflects the fact that these services are important to the community, and that actions aimed at the conservation of these services are important for society, especially under a climate change scenario that predicts a greater likelihood of rapid formation of stronger hurricanes that will impact the Yucatán peninsula [77]. Public policy initiatives that promote conservation of ecosystems can therefore be proposed, including the local concepts that identify them, recognizing community knowledge for the design of policies that can have a local impact. As part of these policies, it is necessary to design nature-based solutions to climate change mitigation and adaptation in order to reduce vulnerability (which was mentioned in our three study sites) and to enhance the resilience of the socio-ecosystem [78]. It is necessary to implement an ecosystembased adaptation plan that maintains the provision of regulatory ESs while providing other important services, such as cultural services (e.g., wider beaches free of garbage to allow a greater appreciation of the natural landscape and maintenance of recreational activities). Silva et al. [79] described a case study in the port of Veracruz, Mexico, in which soft engineering is used to mimic the physical processes of the dune that is maintained by the presence of native vegetation to prevent the movement of sand into the interior of the city. The same authors described a case involving the development of a coastal dune management plan in southeastern Brazil (Cassino Beach) that began in 1988 with the objective of recovering coastal protection, control of aquifer contamination, and restoration of habitat and biodiversity. Since the project started 30 years ago, the regeneration of the dune, development, monitoring, and enforcement of the local dune management plan, construction of a cross-dune boardwalk for pedestrian access to the beach, and public engagement and environmental education programs are described. This type of project acts to promote the recognition of the importance of the dunes by the local population.
In this study, we identified different levels of government, NGOs, and communities that have carried out interdisciplinary work to create alternatives for the access, sustainable use, and management of some of the natural resources of the Yucatán coast [80,81]. However, further efforts and additional actions are needed to promote a harmonious relationship between the environment and society, as mentioned by Castillo-Burguete et al. [82]. Kabisch et al. [78] explored existing barriers and potential opportunities for increasing the effectiveness of implementing nature-based solutions and found that interand transdisciplinary studies are necessary to obtain a successful outcome. In Mexico, several protected natural areas (PNAs) have been decreed along the coast (57% of the total coastline is protected). However, none of these PNAs were particularly designed for the regulation of coastal dunes conservation in the way that other ecosystems or species are indirectly protected by established criteria of how and where to locate a construction or infrastructure [83]. Recently, the norm NMX-AA-120-SCFI-2016 was created to promote a beach quality certification that establishes criteria of environmental, health, safety, and service quality for the sustainability of beaches in terms of the modalities of recreational use and priorities for conservation. This norm promotes the following benefits: (a) it identifies and prevents environmental risk and impacts, (b) improves the image and competitiveness of the destination, (c) protects the environment and the conservation of biodiversity, and (d) places the site at the international forefront in relation to similar schemes. This regulation promotes these benefits but fails to reflect the observed link between local communities, tourists, and authorities that might be useful for influencing inter and transdisciplinary participation for successful projects and the operation of quality certified beaches. This link could serve as a basis for creating adequate governance of environmental problems on the Yucatán coast. For this purpose, it is necessary to promote the creation of participatory mechanisms in environmental and coastal policies, which allow the inclusion of traditional knowledge and the perceptions of each community in the design and implementation of solutions to environmental problems.

Conclusions
Our results indicate that local participants have a clear knowledge of ecosystem services of regulation, easily identifying provisioning and cultural services, but not support services. This lack of awareness of the whole benefits could be addressed in the study locations through training activities and participatory action research to give greater visibility to the variety of ecosystem services provided by the coastal dunes. In this way, the community mentioned the lack of environmental education that could be considered to promote the better use and sustainable management of beach and coastal dunes, incorporating local knowledge and concepts into educational environmental programs. This type of study provides a way of reassessing the knowledge and opinions of those who live day by day in the studied ecosystems. Local people know in depth what is happening in their communities and are a primary source of information that should be considered in decision-making about how to conserve beaches and dunes. The methodological approach developed in this study allows us to explore, qualitatively and quantitatively, the understanding and interpretation of the significance given by the stakeholders to their relationship with the environment. This methodological focus has been of great utility to our comprehension of human behavior in terms of their relationship to natural resources because it enables a profound understanding of the processes, values, emotions, conflicts, and relationships that occur in a socio-ecological context.