A sustainability index for anthropized and urbanized coasts: The case of Concón Bay, central Chile

Applied Geography 116 (2020) 102166

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A sustainability index for anthropized and urbanized coasts: The case of �n Bay, central Chile Conco �pez b, Carolina Rojas c, Jorge Qüense a, Rodrigo Hidalgo a, Carolina Martínez a, d, *, Pablo Lo a Federico Arenas a

Institute of Geography, Faculty of History, Geography and Political Science, Pontificia Universidad Cat� olica de Chile, Avda. Vicu~ na Mackenna 4860, Macul, Santiago, Chile School of Civil Engineering, Faculty of Engineering, University of Bristol, 93-95 Woodland Road, Office 5.4, BS8 1US, Bristol, United Kingdom c Instituto de Estudios Urbanos y Territorial, Pontificia Universidad Cat� olica de Chile, El Comendador 1916, Chile d Centro de Investigaci� on para la Gesti� on Integrada de Desastres Naturales, CONICYT/FONDAP/15110017, Santiago (CIGIDEN), Avda. Vicu~ na Mackenna 4860, Macul, Santiago, Chile b

A R T I C L E I N F O

A B S T R A C T

Keywords: Coast Urbanization Urban sprawl Anthropization Land-use planning

The level of anthropization in one of the most urbanized areas of central Chile (Conc� on Bay, 33� S) is analyzed using a Coastal Sustainability Index (CSI). It is constructed from variables associated with driving forces (pres­ sures) acting on geomorphological units with a known level of fragility (reference). The coastal conservation and intervention status was determined using analytical hierarchy process (AHP) and frequency ratio models com­ bined with GIS. A correlation between driving forces and a high level of sustainability indicates a high degree of conservation of these geomorphological units, while a correlation between driving forces and a moderate or low level of sustainability indicates a high degree of intervention and little conservation of these natural units. It was established that 89.7% of the total area of Conc� on Bay presented low or moderate levels of sustainability, associated with residential and industrial uses and proximity to major roads. The high sustainability areas ac­ count for only 10.3% of the total area and consist of wetlands, beaches and dune fields that are under great pressure from real estate projects and various economic activities. Based on this index and the determination of areas with different sustainability levels, it is possible to orient decision making in land-use planning to control the driving forces in highly anthropized, urbanized coastal zones in order to incorporate conservation measures for coastal ecosystems of high natural and cultural value.

1. Introduction The heavy anthropization in the form of urbanization or other forces exerted on coastal areas is a worldwide concern, especially under the environmental sustainability paradigm, due to the loss of ecosystem functioning and services and degradation of coastal environments �n and de Andres, 2015). UNESCO (1993, in Barraga �n, 2003) (Barraga data support the idea of a planet that is tending toward “coastalization” with a projected 75% increase in the concentration of the worldwide coastal population by 2100, involving more than 11,000,000 people. The coastalization phenomenon brings about grave consequences; for example, it is one of the main causes of mangrove forest retreat in Martinique (Baillard, 2016).

Coastalization primarily implies urbanization, a phenomenon that is the main change agent in coastal areas, as it is a driving force and the cause of the fragmentation, homogenization and degradation of the coastal landscape. The evidence shows how urbanization has caused polarization of space by changing population densities, economic ac­ tivities and mobility, which make urban landscapes highly dynamic, complex and multifunctional (Antrop, 2004). The urbanization of the coast has been exhibited concretely in the spread of low-density urban and residential development in coastal areas of Ireland, Portugal and especially the Spanish Mediterranean (Gaja, 2008), where, due to extensive tourism and migratory forces, there has been an increase in both first- and second-home construction, not only for the Spanish population, but also for Europeans in general

* Corresponding author. Institute of Geography, Faculty of History, Geography and Political Science, Pontificia Universidad Cat� olica de Chile, Avda. Vicu~ na Mackenna 4860, Macul, Santiago, Chile. E-mail addresses: [email protected] (C. Martínez), [email protected] (P. L� opez), [email protected] (C. Rojas). https://doi.org/10.1016/j.apgeog.2020.102166 Received 15 July 2019; Received in revised form 30 December 2019; Accepted 2 February 2020 0143-6228/© 2020 Published by Elsevier Ltd.

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�ndez, 2013). The Atlantic coast of the United States has also been (Herna more vulnerable amid the greater frequency of storm surges and rising sea level scenarios (Wdowinski, Bray, Kurtman, & Zhaohua, 2016). The coasts of the world are urbanizing, and although they account for only 20% of the Earth’s surface, it has been shown that the ecosystem services they provide are equivalent to 77% of the total worldwide value (33,268 � 109 $ US per year), with those provided by wetlands and coastal water bodies particularly significant (Costanza et al., 1997; Martínez et al., 2007). In accord with Hunt and Watkiss (2011), recent IPCC reports, from 2001 to 2007, draw conclusions on the effects of climate change on a city scale, indicating that the most harmful effects occur in settlements that are dependent on natural resources, especially cities located in coastal areas. The effects include rising sea levels, a greater recurrence of extreme hazardous events, acidification and sali­ nization of bodies of water, water scarcity, coastal erosion and changes in ecosystem functioning. In fact, in Massachusetts anthropization increased nutrient concentrations and thus water eutrophication (McClelland, Valiela, & Michener, 1997). Miami, among the cities with the most urbanized coasts, is facing an increase in flooding frequency after reducing the effectiveness of drainage systems, resulting in prop­ erty damage, with rainfall-induced events increasing 33% and tide-induced events more than 400% (Wdowinski et al., 2016). There have also been drastic effects on the degree of naturalness of the coastal landscape, an irreversible process when farmland is con­ verted to built-up space with a consequent risk to food security (Lien & Steinnes, 2016). Despite the high valuation of the coastal landscape due to its functional and landscape qualities and high endemism and biodiversity, coastal areas have undergone fragmentation, loss of iden­ tity and degradation (Antrop, 2004; Baillard, 2016). The urbanization of the coast imposes challenges for sustainability and adaptation to climate change, especially in developed countries, since the dynamics of coastal areas must be understood in order to improve decision making to achieve more innovative land-use planning. There is thus an urgent need for methods and instruments that allow these processes, especially regarding the effects of urban growth on the coast, to be quantified. This need has already been articulated in pre­ vious studies on planning and managing “emerging interurban” multi­ functional landscapes (Antrop, 2004) and providing inputs for the creation of adaptation plans to face the growing risks of coastal use and identify more relevant actions in coastal management (Nichols & Cazenave, 2010). In a sustainability and adaptation context to climate change, it is required to know the socio-ecological and territorial dynamics with the purpose to improve the decision making in territorial planning, whereby it is a priority to have methods that allow quantifying these processes, especially the urban growth. A successful method to the applying of adaptive processes and that it has been applied to coastal areas, is the Cellular Automata-based model (CA), which is oriented to reproduce future scenarios of land-use and urban expansion (He, Okada, Zhang, Shi, & Zhang, 2006; Li & Gar-On Yeh, 2000; Nakao, Cabral de Sousa, de Freitas, & Simoes, 2015). In the natural hazard context, the literature is plentiful, highlighting the Social Vulnerability Index SoVI® (Cutter, Boruff, & Shirley, 2003), and the Analytical Hierarchy Process (AHP)-­ based approach to coastal vulnerability studies as an improvement to the existing methodologies for vulnerability assessment (Koroglua, Rana­ singhe, Jim�eneze, & Dastghei, 2019; Muralli et al., 2013; Sekovski et al., 2020). These indexes are relevant to consider, especially to assess the anthropization given that risks and disasters are conditioning factors for sustainability and human development. Despite these efforts, there are scarce proposals to quantify in an integrated and interdisciplinary manner the anthropization level in fragile coastal systems or high sensitivity areas, with a spatial approach oriented to territorial planning. The literature is plenty on uni-discipline indexes, in special those that �n, value only biological aspects or ecosystems services (García-Ayllo 2018). There on, one of the first was the Integrated Anthropization ~ as, 2010), whereas recent studies Relative Index (INRA) (Martínez-Duen

have focused, for example, on the assessment of diffuse anthropization associated with tourism on coastal environments sensitives to coastal �n, 2018), the Coastal Dune Vulnerability Index lagoons (García-Ayllo (CDVI) (Bertoni et al., 2019) and the Coastal Sustainability Standard method (CoSS), applied in the United Kingdom (Gallagher, 2010) and Italy (Cantasano, Pelliconea, & Iettob, 2020). In this context, Latin America is one of the most urbanized regions of the planet, with 80% of the population residing in urban areas. The process began in the 1950s, but gained momentum starting in the 1970s under the framework of urban-regional transformations resulting from �n, 2013). The coastal economic globalization (Canales & Canales Cero cities of Latin America have undergone rapid demographic growth with a strong link to coastal marine ecosystems, developing local economies dependent on their resources, often with informal use processes that constitute a factor added to the poverty and natural risks that promote �n and De Marías, 2016). inequality and unsustainability (Barraga In the scenario of Latin American coastalization, Chile stands out due to its heavy population concentration and economic activities in three main conurbations (CU) and metropolitan areas (MA) that are coastal �n MA, Greater Valparaíso CU and La Serena-Coquimbo hubs (Concepcio CU). The urban population in these areas is 21% of the national total, although 40% of this national total is concentrated in the Santiago MA, generating strong relationships of dependence in the regional urbani­ zation process and economic model (Mancilla & Fuenzalida, 2010). In all these areas, urban uses on the outskirts have intensified, triggering fragmented low-density development characterized by high residential segregation (Hidalgo & Arenas, 2009, pp. 9–29). The Chilean coast contains ecosystems with high natural and cultural value, but the impacts of urban sprawl, mainly in metropolitan areas, result in economic, social and environmental costs (Rojas, Pino, Basnou & Vivanco, 2013). In coastal cities such as Valparaíso, the most fragile and affected environments have been wetlands, beaches and dune fields, which have been assimilated into urban growth as a result of their �n has become emblematic of wetland landscape quality, while Concepcio �nguiz, Pino, & loss and vulnerability to risks (Rojas, De la Barrera, Ara Munizaga, 2017; Rojas et al., 2017). The objective of this work is to identify coastal sustainability areas in anthropized, urbanized environments through an anthropization index �n in the Valparaíso Metropolitan Area, the applied to the city of Conco urban growth of which is among the most intense in the country in recent decades. For the purposes of this work, anthropization will be understood as the level of intervention in or alteration of a natural system as a result of human activities, which causes a loss in its degree of naturalness expressed in terms of structure or func­ tioning and, therefore, a decrease in environmental sustainability. Thus, a coastal ecosystem that exhibits intervention and degradation loses its capacity to provide resources and ecosystem services and its resilience for future societies, with human development therefore compromised as well (Morelli, 2011). The identification of areas with a higher or lower level of coastal sustainability will aid decision making in land-use planning in order to promote the rational use of resources and coastal conservation and governance, especially in a context of climate change. 2. Geographical context �n is located in central Chile (32� 560 S and 32� The coast of Conco �n Point in 490 3000 S) and is defined by the rocky promontories of Conco the south and Ritoque Point in the north (Fig. 1). It is a north-facing headland bay, with an Andean river (the Aconcagua) that flows into the sea in its northern section, forming a microtidal estuary. It presents a 30-km-long sandy shore and a varied system of coastal environments such as wetlands (Aconcagua River and Mantagua River), dune fields (Mantagua and Ritoque) and beaches, with different levels of anthrop­ ization. The Ritoque dune field is one of the biggest in central Chile l (1923.5 ha). Castro (1987 and 2015) identified a wide variety of dune 2

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Fig. 1. Geographical context of the study area (Conc� on Bay).

Fig. 2. Methodological framework. 3

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types such as foredunes, transverse dunes, longitudinal dunes and transgressive dunes, some with forest control, and an interdune depression on the northern part of the bay that presents vestiges of prehistoric shell mounds, which to date lack legal protection. �n Bay encompasses two coastal com­ In administrative terms, Conco munes, delimited by the banks of Aconcagua River and geared toward �n (tourism) and Quintero (in­ opposing economic activities: Conco �n area along the bay presents activities related to dustry). The Conco tourism and the oil industry, while Quintero is entirely rural, although the community as a whole is oriented distinctly toward industry, and is considered an “environmental sacrifice area”. The next most represen­ �n Bay are residential, recreational and indus­ tative land uses on Conco trial, activities that coexist in a small area of 20 km2. The tourism focus �n contrasts with the port-industrial activity in Quintero. of Conco

0–400 m, 400–1600 m and greater than 1600 m (Fig. 3C). Distance to built-up areas: the linear distance from each unit of analysis (pixel) to the edge of the nearest built-up area was calculated in order to subsequently classify the result into three classes, in accord with Park, Jeon, Kim, and Choi (2011) 0–400 m, 400–1200 m and > a 1.200 m (Fig. 3. D). 3.3. Relationship of fragile areas to driving forces To determine the relationship between the fragile units (geo­ morphology) and driving forces (land cover, distance to major roads and distance to built-up areas), a bivariate statistical approach was used, the result of which allowed the degree of conservation and intervention of these natural units to be established. A correlation between driving forces and a high level of sustainability indicates a high level of con­ servation of these units. Meanwhile, a correlation between driving forces and a moderate or low level of sustainability indicates a high degree of intervention in these natural units. These relationships were assessed using the frequency ratio model, which measures the spatial relationship between the level of sustainability of each driving force and each fragile unit. In accord with Rasyid, Bhandary, and Yatabe (2016), the frequency ratio model is described by the following formula: P ðijÞ= PixL P RF ¼ PðijÞ= Pix

3. Materials and methods �n Bay a two-stage To analyze the level of anthropization on Conco methodology was designed (Fig. 2). The first stage (Stage I) consisted of the assessment of the driving forces regarding the conservation and �n Bay. Here it intervention status of the geomorphological units of Conco was assumed that the geomorphology represents a reference condition for the level of naturalness of the coastal system; thus, all human intervention must be correlated with a level of fragility. The second stage (Stage II) consisted of the calculation of the level of coastal sustainability.

where RF is the frequency ratio model, ij is the number of pixels of the P level of sustainability of each driving force, PixL is the total sum of pixels of each level of sustainability, PðijÞ is the number of pixels that P correspond to each geomorphological unit and Pix is the total pixels in the study area. A resulting value greater than 1 presents a strong relationship between variables, while a value lower than 1 indicates a weak relationship (Wang & Li, 2017).

3.1. Data preparation To determine the coastal sustainability areas a geospatial database was constructed in GIS using the following variables: geomorphology, land cover, road network and built-up areas. In addition, building per­ mits (1997–2012) and the evolution of the urban area (1993–2013), provided by Fondecyt project no. 1120223, were included as analysis variables. These geospatial data allowed the driving forces – land cover, distance to major roads and distance to built-up areas – to be determined and related to the fragile units, as indicated by geomorphology. Subse­ quently, the driving forces and fragile units were used for the calculation of coastal sustainability areas.

3.4. Stage II. coastal sustainability areas 3.4.1. Ranking of coastal sustainability factors Given that the factors used to determine coastal sustainability areas were calculated in different units of measurement, the values were normalized through a sustainability ranking, in which the classes of each factor were valued on the basis of their intervention and conservation status. This ranking, created from a uniform rating scale, was based on the work of Dai, Lee, and Zhang (2001), who established a scale of 1–10, where: a value between 1 and 3 corresponds to a high level of sustain­ ability, a value between 4 and 6 corresponds to a moderate level of sustainability and a value between 7 and 10 corresponds to a low level of sustainability (Table 1). Subsequently, the proposed values were normalized on a 0–1 scale (Table 2) using a linear standardization function (Nouri, Mason, & Moradi, 2017). This process allowed a sustainability threshold to be established in order to identify the human intervention and conservation �n Bay through a combined GIS and status of the natural spaces of Conco analytical hierarchy process (Malczewski & Rinner, 2015). The sus­ tainability levels are described below:

3.2. Stage I. Conservation and intervention status The fragile units were obtained from the geomorphological units determined from photointerpretation of a CONAMA-CONAF (2001) aerial photograph (1:20.000 scale). To define the units the works of Thomas (1958, p. 86), Figueroa (1968), Caviedes (1967, 1972), Castro (1987) and Martínez (2009) were consulted. The identified fragile units were: active cliffs, foredunes, longitudi­ nal dunes, transgressive dunes, interdune depression, transverse dunes, relict dunes, valley bottom, beaches, rivers, fluvial terraces I and II, terraces with ancient dune cover (100 m.a.s.l.) and terrace level II (100–200 m.a.s.l.) (Fig. 3. A). Meanwhile, the driving forces were calculated based on: Land cover: land cover was obtained from photointerpretation of a 5x5-m resolution Google Earth mosaic from 09/03/2017 using the �n developed by Rojas, classification method for the coast of Concepcio Pino et al. (2013). The identified land covers were: built-up areas, native forest, water bodies, crops, wetlands, shrubland, grassland/prairie, forestry plantation, bare soil, beaches, dunes and shoals (Fig. 3. B). Distance to roads: for this factor the Ministry of Public Works (2012) road network that includes the first- and second-category paved road network was used. Next, the linear (Euclidean) distance was calculated with GIS software. This process assigned a linear distance value in me­ ters to each pixel in the study area to the nearest road. Subsequently, the distance was classified into three categories, in accord with the prox­ imity criterion proposed by Bagheri, Sulaiman, and Vaghefi (2013)

3.5. Analytical hierarchy process (AHP) To determine the coastal sustainability areas, the factors were weighted using the Analytical Hierarchy Process (AHP), proposed by Saaty (1987), where a pairwise comparison matrix that determined the relative importance of each factor was established (Ju, Jia, Shan, Tang, & Ma, 2012). The level of importance was determined using a contin­ uous scale for assigning value judgments (Table 1), which goes from a �mez and Barredo, 2005). minimum value of 1/9 to a maximum of 9 (Go The value judgments established a series of weights that describe the order of priority of each factor. This process was carried out through 4

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Fig. 3. Coastal sustainability factors: A. Geomorphology; B. Land cover; C. Distance to roads; D. Distance to built-up areas.

5

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significant degree of uncertainty or subjectivity. Thus, the consistency ratio (CR) was calculated, which indicates if the value judgments assigned to each factor are consistent with their actual importance (Bagheri et al., 2013). The consistency ratio is expressed as:

Table 1 Ranking of coastal sustainability factors. Factors

Geomorphology (F1)

Sustainability score

Sustainability Level

Fragile units

Beach Active cliff Transverse dune Interdune depression

10 9 9 8

High

Relict dunes

5

Moderate

Terrace with ancient dune cover (100 m.a.s.l.) Fluvial terrace I Fluvial terrace II Longitudinal dune Transgressive dunes Foredune Valley bottom River Terrace level II (100–200 m.a.s.l.)

4

Low

Factors

Land cover (F2)

Sustainability score

Sustainability Level

Driving forces

Native forest Wetlands Beaches, dunes and shoals

10 10 10

High

Bodies of water Crops Shrubland/Prairie

5 6 6

Moderate

Bare soil Forestry plantation Built-up area

3 1 1

Low

Distance to Roads (F3)

Sustainability score

Sustainability Level

>1600 m 400–1600 m 0–400 m

8 5 1

High Moderate Low

Distance to Urban Area (F4)

Sustainability score

Sustainability Level

>1200 m 400–1200 m 0–400 m

8 5 1

High Moderate Low

CR ¼

CI RI

where RI is a random index and CI is a consistency index that is expressed as: RI ¼

4 4 3 3 2 2 2 2

ðλmax nÞ ðn 1Þ

where ʎmax is the maximum Eigenvector obtained from the product of the normalized principal Eigenvector and the pairwise comparison matrix, and the closer ʎmax is to n, the more consistent the result (Ju et al., 2012). The result of the consistency ratio for CR values greater than or equal to 0.10 indicates that the value judgments must be reviewed, since they are not sufficiently consistent to establish the weights ðwjÞ. Meanwhile, for CR values lower than 0.10, the assigned value judgments are considered satisfactory (Sahoo, Dhar, & Kar, 2016). Once the consistency of the weights established for each factor is esti­ mated, the coastal sustainability index was applied using the weighted sum method, in which, based on the sum of the product of the weight of each factor and the score corresponding to its categories, the areas of �n Bay were assessed. The lowest to greatest sustainability on Conco method is expressed as follows. n X

CSI ¼

wj *xij

j¼1

where CSI is the coastal sustainability index, wj is the weight of each �mez and Barredo, factor and xij is the score of category i in factor j (Go 2005). The weighted values for each factor (Table 3) allowed the factors of lowest to greatest sustainability to be assessed as a function of their different levels of intervention and degradation. Finally, the coastal sustainability index was applied to the factors and integrated and assessed in ArcMap 10.4 using the Weighted Overlay tool, where the areas of lowest to greatest sustainability were determined. 3.6. Sustainability level

Table 2 Sustainability level and factor standardization. Sustainability score

Standardized Score

Sustainability Level

Description

1 2 3 4

0.0 0.1 0.2 0.3

Low

Evident human intervention

5 6 7

0.4 0.6 0.7

Moderate

Fragile conservation status; susceptible to human intervention

8 9 10

0.8 0.9 1.0

High

Adequate conservation status

The coastal sustainability index was calculated according to the following formula. CSI ¼ Geomorphologyð0:41Þ þ Landcoverð0:36Þ þ Distance to Roadsð0:12Þ þ Distance to Urban Areasð0:11Þ The coastal sustainability index establishes a standardized result with values ranging from 0 to 1, with values near 0 indicating high sustainability and values near 1 low sustainability. This result was reclassified in accord with break values (Table 4), with previously defined sustainability ranges established (Table 1). These ranges deter­ �n Bay. mined the areas of sustainability on Conco

normalized principal Eigenvector calculation, which relates the weights as a function of the established judgments (Saaty, 1987). This method consisted of normalizing the pairwise comparison matrix values through the quotient of each value ðaijÞ and the value of the sum of each column P ð aij Þ, with the resulting value added by row to obtain the principal Eigenvector. The obtained result was normalized by dividing the sum of each row by the number (n) of variables used, with the result repre­ �mez and Barredo, 2005). The senting the weight ðwj Þ of each factor (Go assignment of value judgments by the authors generated a somewhat

Table 3 Analytical hierarchy process (AHP). Coastal Sustainability Index Variables Geomorphology Landcover Distance to roads Distance to urban areas

6

F1 F1 1 F2 1 F3 1/3 F4 1/5 *Cr: 0.02

F2 1 1/3 1/3

F3

1 1

F4

Pesos

1

0.41 0.36 0.12 0.11

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water, the main interventions were reflected in the decrease in flows in periods of water scarcity and pollution associated with industrial pro­ duction. In addition, the crop land cover presented a strong correlation with terrace level II (200 m.a.s.l.), with an FR value of 21.6, due to the intensive use of arable land in this unit, where the degree of intervention was evidenced by the replacement of natural covers, especially grass­ lands and shrubs, as a result of arable land expansion. Other covers such as shrubland and grassland affect longitudinal dune, transgressive dune and terrace with ancient dune cover (100 m.a. s.l.) units, with FR values ranging from 1.4 to 1.8. This type of cover also presented a high correlation with interdrune depression, dune terrace I and terrace level III (100–200 m.a.s.l.) units, with FR values between 1.0 and 1.2. This is due to a decrease in the stabilization role that this cover plays in the conservation status of these geomorphological units. In addition, regarding distance to roads between 400 and 1600 m, a high correlation with longitudinal dunes and transverse dunes was observed, with FR values of 1.6 and 1.2, respectively, and with terrace with ancient dune cover (100 m.a.s.l.) and fluvial terrace I, with an FR value of 1.1. With respect to distance to urban areas between 400 and 1200 m, a high correlation with longitudinal dune, with an FR value of 2.9, transverse dune, with an FR value of 1.9, and terrace with ancient dune cover (100 m.a.s.l.) units, with an FR value of 1.7 was observed. This indicates the degree of fragility of these units given the urban expansion process, especially the peri-urbanization of gated communities and in­ dustrial infrastructure that, due to its proximity to urban centers, also exerts a degree of intervention through accessibility from peri-urban areas. It was established that the low-sustainability covers most influence the level of conservation of the geomorphological units and thus present the most intervention and least conservation (Table 7). The built-up area cover presented a high correlation with the terrace level (FR 1.0), II (FR 3.0) and III (FR 1.3) units and cliffs, with an FR value of 1.8. This is due �n), with buildings to the increasing real estate supply in the area (Conco tending to occupy the marine terrace levels. Other low sustainability covers such as forestry plantations presented a high correlation with longitudinal dunes, reaching an FR value of 4.4. This dune area has been the target of stabilization efforts using plantations to reduce the advance of the dune front over the marine cliff level, that is, 80 m.a.s.l. In addition, correlations with fluvial terrace II, terrace with ancient dune cover and terrace level III were observed. Similarly, the bare soil cover presented a correlation with the foredune, fluvial terrace I, transverse dune and terrace level II (100–200 m.a.s.l) units. Regarding distance to major roads between 0 and 400 m, it was determined that the units with the greatest intervention are relict dunes and valleys, with RF values of 2.5 and 2.0 respectively; other units also presented a strong correlation, with RF values between 1.0 and 1.5.

Table 4 Coastal sustainability ranges. Break values

Sustainability level

0–0.3 0.3–0.7 0.7–1

Low Moderate High

4. Results 4.1. Conservation status This analysis allowed the land cover type that most influences the conservation status of the geomorphological units to be identified. Regarding high sustainability covers, it was established that native forest has a high correlation with the river geomorphological units, with an FR value of 1.8 (Table 5). This same cover also presented a significant correlation with fluvial terrace I and terrace level III, with FR values of 1.1 and 1.5, respectively. In addition, wetlands, also considered to have a high level of sustainability, presented a strong correlation with valley geomorphological units, with an FR value of 7.2, and interdune depression units, with an FR value of 4.1 (Table 5). Finally, the beach, dune and shoal covers presented a strong correlation with most of the geomorphological units, especially beaches, with an FR value of 9.9, relict dunes, with an FR value of 7.5, and cliffs, with an FR value of 6.1, units in which the greatest correlation was presented (Table 5). Other units such as foredune, interdune depression and transverse dunes pre­ sented a high correlation, with FR values of 14.7, 2.2 and 5.6, respec­ tively (Table 5). In relation to the distance to roads, a high correlation was observed in units that are at least 1600 m from major roads. These units are transgressive dunes, with an FR value of 6.0, and the interdune depression, with an FR value of 5.6 (Table 5); other units such as the foredune, transverse dunes and beach also presented a high correlation, with FR values between 3.0 and 3.7, respectively. With respect to a distance to urban areas over 1200 m, a high correlation was observed in the same geomorphological units that are more than 1600 m from major roads (Table 5). 4.2. Intervention status Based on Table 6, the geomorphological units that present a better conservation status due to their level of intervention were established. Land covers significantly influence the level of conservation, especially in fragile geomorphological units such as wetlands and dunes. The greatest correlation values were observed on the beach, interdune depression and level II fluvial terrace units. In the case of bodies of Table 5 Frequency Ratio (FR) High Sustainability factors. Geomorphological Class

Cliff Foredune Longitudinal Dune Transgressive Dunes Interdune Depression Transverse Dune Relict Dunes Valley Beach River Terrace with Ancient Dune Cover (100 m.a.s. l.) Fluvial Terrace I Fluvial Terrace II Terrace Level III (100–200 m.a.s.l.)

High Sustainability Native Forest (NF)

Wetlands (WT)

0.1

0.3 0.6

0.0 0.8 0.5

4.1 0.2

0.6

7.2

1.8 0.1

1.0 0.1

1.1 0.2 1.5

0.5

Beach, Dunes and Riverbanks (BDR) 6.1 4.7 0.1 0.6 2.0 5.6 7.5 0.1 9.9 0.4

Road Distance (>1600 m)

Urban Distance (>1200 m)

3.0 1.8 6.0 5.6 3.7

2.9 2.9 6.0 5.7 4.0

0.0 3.3

3.1

1.8

0.8

0.1

0.1

0.1

0.5

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Table 6 Frequency Ratio (FR) Moderate Sustainability factors. Geomorphological Class

Moderate Sustainability Water Bodies (WB)

Cliff Foredune Longitudinal Dune Transgressive Dunes Interdune Depression Transverse Dune Relict Dunes Valley Beach River Terrace with Ancient Dune Cover (100 m.a. s.l.) Fluvial Terrace I Fluvial Terrace II Terrace Level III (100–200 m.a.s.l.)

Agricultural Land (AL)

Bush and Grasslands (BGR)

Roads Distance (400–1600 m)

Urban Distance (400–1200 m)

0.8 1.0 1.6 0.9 0.9 1.2

0.2

0.2 0.6 1.4 1.8 1.2 0.8 0.2 1.0

1.1 0.7 2.9 1.6 1.4 1.9 0.2 0.9 0.9 0.7 1.7

3.4 0.1 1.5 0.0 0.0 2.0 1.1 62.5 0.9 1.1 0.4

0.3 21.6 0.2

Low Sustainability

Cliff Foredune Longitudinal Dune Transgressive Dunes Interdune Depression Transverse Dune Relict Dunes Valley Beach River Terrace with Ancient Dune Cover (100 m.a.s. l.) Fluvial Terrace I Fluvial Terrace II Terrace Level III (100–200 m.a.s.l.)

1.8 0.7

Builtup Area (BA)

0.0

Forest Plantations (FP)

4.4 0.2 0.1

Bare Soil (BS)

1.7

0.0 0.8 0.9 0.2 0.0 0.3

0.3

1.6

0.5 0.0 0.1 2.0

1.0 3.0 1.3

1.5 0.4 1.2

0.3 1.6 1.4

0.6

Road Distance (0–400 m)

Urban Distance (0–400 m)

1.5 0.5 0.0 0.1

1.1 0.8 0.0 0.1 0.2

0.2 2.5 2.0 0.6 1.4 0.7

0.3 1.4 1.2 0.7 1.2 0.8

1.0 1.3 1.2

1.1 1.5 1.2

1.2 0.2 1.0

1.1 0.9 1.0

1.0 0.7

its urban area was 14.5 km2 (31.5%). By 2017 the urban area had increased to 19.7 km2 (42.8%) (Fig. 4). The foregoing is strongly asso­ ciated with an increase in building permits in the 1992–2002 period (11%), especially for major real estate projects involving high-value properties. The average cost of these properties is 4050 UF, higher – US$35.10, January than in neighboring coastal communes (1 UF– 2015).

Table 7 Frequency Ratio (FR) Low Sustainability factors. Geomorphological Class

0.1 1.5

0.4 0.9 0.9 1.1

4.3. Relationships between factors Regarding the relationship between high sustainability factors (Fig. 5A), a high correlation was established, with RF values near 1, between beach, river and shoal land covers and distance to major roads over 1600 m and distance to urban areas over 1200 m. This is consistent with the better conservation status of the units, since they are spaces that are more distant from the road network. Thus, the contribution of high sustainability factors to the geomorphological units is directly related to urbanization processes in peri-urban spaces, which undergo interven­ tion due to the accessibility to main urban areas they offer and where the natural setting favors the development of gated communities and tourism and industrial infrastructure. It is also directly related to dis­ tance and accessibility from urban areas and major roads. Regarding moderate sustainability factors (Fig. 5. B), a high corre­ lation between the shrubland and grassland cover and distance to major roads between 400 and 1600 m and distance to urban areas between 400 and 1200 m was observed. This correlation, with values over 0.92, in­ dicates loss and fragmentation of natural covers in the space in which peri-urban processes take place, with dunes and terraces especially affected. The foregoing is manifested in the siting of gated communities and economic activities near the urban area and natural spaces, pro­ moting a fragmented urban sprawl process very characteristic of metropolitan areas. Regarding the low sustainability factors (Fig. 5C), a high correlation with all the factors, with RF values near 1, was observed. The built-up area, forestry plantation and bare soil covers, as well as distance to urban areas and major roads between 0 and 400 m, generate the greatest degree of intervention in the geomorphological units, especially cliffs, terraces, valleys and dunes. Thus, urbanization processes and the main economic activities, such as forestry plantations, are the primary inter­ vention factor in the geomorphological units. This intervention is manifested through the modification of the natural covers that regulate the functioning of fragile units such as cliffs, terraces, valleys and dunes. In accord with Table 8 and Fig. 6, 89.7% of Conc� on Bay presents a low or moderate level of sustainability. The low sustainability areas are distributed entirely in the Conc� on Commune (southern area of the bay) and associated with a residential use that coincides with greater

With respect to distance to urban areas between 0 and 400 m, a high correlation with a high degree of intervention was observed in the same geomorphological units that presented such a correlation regarding distance to major roads between 0 and 400 m (Table 7). Thus, covers such as built-up areas, forestry plantations and bare soil exert a degree of intervention on terrace, dune field and cliff units through the modifi­ cation of the morphogenetic balance and transformation of the natural covers that regulate these units, establishing low sustainability of the natural state of highly fragile geomorphological units. In addition, proximity to major roads and urban areas evidenced a degree of inter­ vention through the loss of natural land covers, with consequences in landscape fragmentation and biological diversity transformations in the geomorphological units due to urbanization processes in the peri-urban space. Urban expansion during the 1993–2011 period was constant along ~ o Ave.). the coastline, especially around the main coastal road (Borgon ~ a del However, it must be noted that until 1993 this space was part of Vin �n became a commune that year. Nonetheless, Mar Commune, as Conco �n Dunes Nature Sanctuary can be urban expansion into the Conco detected, exerting heavy environmental pressure on the area. In 1993 �n Commune had an urban area of 4.3 km2 (9.3%), while in 2011 Conco 8

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Applied Geography 116 (2020) 102166

Fig. 4. Evolution of the urban area on Conc� on Bay (1993–2017 period).

investment in real estate projects, as well as industrial use (oil refinery) (Fig. 7). Other low sustainability areas in the rural Quintero area are distributed along major roads, including the only coastal road between Valparaíso and Quintero, where wetland plots have been incorporated into tourism projects and second home developments. The high sustainability areas make up only 10.3% of the total area and are located around the Mantagua wetland and Ritoque beach and dune field (Fig. 8). These areas interact with other areas of moderate sustainability since although they present a degree of naturalness, human activities have generated alterations in the fragile coastal units. In this regard the Aconcagua River wetland, which has progressively lost its level of naturalness due to the effects of various dysfunctional and incompatible activities (industrial, urban, tourism), is notable.

original form or physical context (littoral cell or bay); therefore, the results can be integrated into other analysis contexts, such as integrated coastal area management. The three main urban centers of the country have developed along coastal axes that today make up the primary metropolitan areas in the country, which account for 61.5% of the na­ tional population. The effects of this development are numerous due to the low urban and social resilience characteristic of this coast and the fact that large areas of coastal wetlands and dune fields have been built on almost without restrictions, with forms of use that are currently un­ sustainable in the face of climate change. Although the literature of anthropization indexes on coastal sensitive environments is plenty, the majority is produced in specified disci­ plinary ambits, highlighting those that come from biology (García-Ayll� on, 2018). Nonetheless, there are few with an interdisci­ plinary and spatial analysis approach that allows supporting the deci­ sion making on territorial planning. Some outstanding efforts and applied to coastal areas have been oriented to asses coastal erosion (Zhu et al., 2019); some examples are the Coastal Dune Vulnerability Index (CDVI) (Bertonia, Sartia, Alquinib, & Ciccarelli, 2019), for the analysis of diffuse anthropization associated with tourism in sensitive coastal �n, 2018); the Indicator-based Sustainability environments (García-Ayllo Assessment Tool (InSAT) to assess the changes in sustainability before, during and after the implementation of coastal and marine management measures (Karnauskaite, Schernewski, Støttrup, & Katar�zyte, 2019); and the Coastal Sustainability Standard (CoSS) to assess the integrated coastal areas and river basin management (Cantasano et al., 2020). �n (2018), which is currently gaining In accordance with García-Ayllo more and more weight in this field is the spatial analysis through land-use and land-cover change assessment. The latter is highlighted in the scope of Geography, however, it attracts the attention of the scarce importance assigned to geomorphology as the spatial expression of the basic component of territorial planning, since this one can explain greatly the wide development of dysfunctionalities between land-use on sensitive environments such as coastal ecosystems. This certainly

5. Discussion Why a Sustainability Index for anthropized and urbanized coasts? Because the assessment of various anthropization conditions pre­ sented by large urban and metropolitan areas around the world, which are located mainly on the coast, is currently a global concern. From a geographic point of view, it is of particular interest as evaluation al­ ternatives contribute to decision-making and actions that can halt or reverse degradation processes in ecosystems of great natural and heri­ tage value. Because sustainable coastal resource management requires the safeguarding and transmission to future generations of a level and quality of natural resources that will provide an ongoing yield of eco­ nomic and environmental services (Pethick & Crooks, 2000). Finally, because the conservation status of the coastal zone reflects the devel­ opment model of a country, its governance and territorial planning at different levels; thus, having tools that facilitate territorial assessments to achieve high levels of sustainability is a priority. The coastal sustainability index (CSI) presented here proved to be an effective method for assessing the level of anthropization in a highly urbanized coastal area, which in turn can be analyzed on the basis of its 9

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Fig. 5. A. High sustainability; B. Moderate sustainability; C. Low Sustainability.

variety of fragile coastal environments, with the geomorphological units that compose them taken as a reference, as they reflect a known ideal degree of naturalness. Considering that wetlands, dunes and beaches intrinsically present a high degree of naturalness, the variable that best describes them is their geomorphology, making it a good variable that reflects their conservation status. In the analyzed case, the greatest level of sustainability was presented in the dune fields, one of the wetlands (Mantagua) and the beaches, all located north of the bay in coastal areas (rural) administered by the Quintero Commune. In addition, the urban sprawl pattern is clearly identified given the configuration of urban �npatches that follow the main coastal route, allowing the future Conco Quintero conurbation to be projected along this axis. Although these urban patches do not yet have significant urban density, it is possible to foresee that once urban services are consolidated and the real estate market develops they will have an urban functionality similar to that of �n Commune, which the southern part of the bay, which belongs to Conco is characterized by residential and tourism uses. This is consistent with the analysis carried out by Barrag� an and De

Table 8 Sustainability levels. Sustainability Level

Surface (ha)

Surface %

Low Sustainability Moderate Sustainability High Sustainability

4246.0 5098.6 1072.8

40.8 48.9 10.3

constitutes a broad line of research to develop, especially considering the challenges facing climate change scenarios. The proposed Coastal Sustainability Index (CSI) expands the importance of geomorphology and integrates through it, a series of spatial expression variables that can be adjusted to the geographical context of the different coastal envi­ ronments in the world. The results established that the land cover variables, distance to major roads and distance to urban areas allow an adequate spatial dif­ ferentiation of the level of conservation of and human intervention in a

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Fig. 6. Spatial distribution of the coastal sustainability areas, Conc� on Bay.

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aggressive in Europe. Some studies have established considerable expansion in Europe on three scales, with highly affected regions in central Europe and along the Mediterranean coast, due to which a Eu­ ropean expansion strategy has been proposed, including the imple­ mentation of goals and limits and a set of concrete measures to control and use land in a more resource-efficient manner (Hennig et al., 2015). In Latin America and Chile, urbanization is a dynamic process of accelerated development, with considerable growth rates in terms of urban development on the outskirts, where sprawl is the new physical �pez-Goyburu, form of large urban systems (Hidalgo & Zunino, 2011; Lo 2012). In Chile, metropolitan areas generate synergies in regional urbani­ zation, characterized by a limited urbanizable area and high land values, resulting in social exclusion, marginalization and gentrification due to the high valuation of the natural coastal landscape in which most of the real estate supply is located, transforming the natural conditions of these places into goods that are transferrable on the market (Mancilla & Fuenzalida, 2010). Pauchard et al., (2006, in Salinas & P�erez, 2011), analyzing urbanization, landscape homogenization and loss of biodi­ �n Metropolitan Area, established that urbani­ versity in the Concepcio zation is one of the main causes of biodiversity loss and homogenization of natural settings and contributes habitat fragmentation and changes in biodiversity structure and composition. Recently, Rojas, De la Barrera, �nguiz, Pino, and Munizaga (2017) established that urbanization is Ara the main cause of wetland loss in coastal metropolitan areas of the country, reducing crucial ecosystem services for human settlements, especially regulation of floods (tsunamis, river floods and storm surges), which is considered highly relevant in the context of disasters. In summary, coastal areas seem to present faster urban growth pro­ cesses than other territories and regulatory responses to their effects (inequality, segregation, poverty, pollution) are slower because they are not foreseen promptly, with transformations occurring without public �n and policies capable of adjusting to the changes (Bair, 2009 in Barraga De Marías, 2015). On the Chilean coast, irregular land use has emerged both on the outskirts of large metropolitan areas and within them, with occupation of dune fields and beaches giving rise to shantytowns, squatting and settlements with an unregulated land market for low-income sectors, which contrasts with second home development for the higher-income population, resulting in new social phenomena that overlap with the gentrification and segregation of the coastal landscape characteristic of the last 30 years in the country, although both result in the degradation of coastal ecosystems. This development is also pro­ moted by accessibility needs that bring about a considerable increase in

Fig. 7. A. Real estate projects in Conc� on, located on marine terraces and dunes. B. Estuarine zone of the Aconcagua River. The southern river bank delimits Conc� on Commune, characterized by residential use and the location of the Conc� on Oil Refinery, which has operated since the 1950s and generated numerous oil spills along the coast.

Marías (2015), in which it is indicated that coastal cities and agglom­ erations (CCAs) have developed mainly around bays and coastal la­ goons, environments that are associated with the provisioning of resources and transport networks. In a context in which global urbanization has increased from 29% in 1950 to 50% in 2008 and which is associated with the rhythm of urban �n and De Marías, population growth in less developed countries (Barraga 2015), there is necessary concern regarding how to approach land-use planning in these countries. Urban expansion processes have also been

Fig. 8. Ritoque dune field. A. Foredunes, with mound forms, extending various kilometers inland; their conservation status has been reduced in the south. B. Mantagua area dune field, where foredunes interact with the Mantagua wetland, generating wet areas around the interdune depression. This is one of the areas with the greatest biodiversity, although it is not legally protected. C. Ritoque dune field, trans­ verse dune area. These dunes contain prehistoric shell mounds (not protected by the government) that are exposed to and have been progressively destroyed by dysfunctional off-road activities (motocross and all-terrain vehicles) D. Advancing transverse dune front; in the background the fluvial valley of Quintero stream can be observed, which gives rise to the Mantagua wetland.

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demand for transport-related infrastructure and certainly results in the loss of ecosystem services. A significant part of the anthropization found in this investigation is explained by the siting of transport networks and real estate pressure, which present strong synergistic relationships that give rise to urban sprawl in the area. �pez, Martínez, and William Recently, Rangel-Buitrago, Contreras-Lo (2018) analyzed scenic quality in 96 sites on the coast of the Valparaíso Region, finding abundance of classes III, IV and V (the lowest quality levels) in 78% of the sites due to the effects of human activities. They also found that 51% of the sites presented class V (the worst quality) due to urbanization, port activity, coastal erosion, garbage and pollution, along with the lack of trash management, especially of plastics. Although this is a worldwide problem (Anfuso et al., 2017; Burak, Dogan, & Gazioglu, 2004; Jambeck et al., 2015; Rangel-Buitrago, 2019; Ryan, Moore, van Franeker, & Moloney, 2009), on the Chilean coast it is having very negative effects on the conservation status, including coastal environments with legally protected status (Ramsar El Yali site). The areas established in this work as having high coastal sustain­ ability, which include beaches, free dunes of the Ritoque dune field and the Mantagua wetland, require urgent legal protection. They are currently defended by citizen and surfer movements, although they lack protection alternatives and have been under heavy human pressure for decades as a result of legal and illegal economic activities and the real ~ a, 1987, pp. 1–16; Paskoff estate industry (Castro, 1987; Castro & Vicun & Manríquez, 2004, p. 112).

Acknowledgements We are grateful for the FONDECYT N 1190251, N 1150360, N11191011 and FONDAP N 15110017 grants from the National Scien­ tific and Technological Research Commission (CONICYT) of Chile. Appendix A. Supplementary data Supplementary data to this article can be found online at https://doi. org/10.1016/j.apgeog.2020.102166. References Anfuso, G., Williams, A. T., Casas Martínez, G., Botero, C., Cabrera, J. A., & Pranzini, E. (2017). Evaluation of the scenic value of 100 beaches in Cuba: Implications for coastal tourism management. Ocean & Coastal Management, 142, 173–185. Antrop, M. (2004). Landscape change and the urbanization process in Europe. Landscape and Urban Planning, 67, 9–26. Bagheri, M., Sulaiman, W., & Vaghefi, N. (2013). Application of geographic information system technique and analytical hierarchy process model for land-use suitability analysis on coastal area. Journal of Coastal Conservation, 17, 1–10. Baillard, K. (2016). 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6. Conclusions A coastal sustainability index (CSI) was applied to an area of the central Chilean coast characterized by major anthropization in the form of urban growth, incorporating the driving forces acting on fragile coastal environments. Urban areas, forestry plantations, bare soil, dis­ tance to urban areas and major roads were the main factors in the low �n Bay, all of which sustainability of the geomorphological units of Conco is associated with the urban sprawl characteristic of Chilean metropol­ itan areas. In this investigation it was established that 89.7% of the total area of �n Bay presented a low or moderate level of sustainability, mainly Conco associated with the driving forces of residential and industrial uses and proximity to roads. This condition has been promoted by the urban sprawl model, which has assimilated rural coastal areas in the north, following the axes of the main routes, and tending toward Conc� onQuintero peri-urbanization. High sustainability areas account for only 10.3% of the total area and consist of wetlands, beaches and dune fields that are under great pressure from real estate projects and various economic activities. Thus, there is an urgent need to regulate land use through land-use planning instruments that are consistent with sus­ tainability principles. The Coastal Sustainability Index (CSI) is proposed as a method to value with an interdisciplinary approach the effects of that generates the driving forces on the coastal sensitive physical-natural components, especially on the geomorphology. Therefore, the method is susceptible to be applied to studies with a socio-ecological approach system, for adaptive processes against climate change scenarios and territorial planning, where it is required to apply decisions on protection or regulation of current or future uses in urbanized coasts or with urbani­ zation potential. Declaration of competing interest We wish to draw the attention of the Editor to the following facts, which may be considered as potential conflicts of interest and to sig­ nificant financial contributions to this work. We wish to confirm that there are no known conflicts of interest associated with this publication and there has been no significant financial support for this work that could have influenced its outcome. 13

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