ارزیابی زیست محیطی استراتژیک در آمریکای لاتین : پیشنهاد روش شناختی برای برنامه ریزی شهری در منطقه شهری کونسپ سیون (شیلی)

This work describes a methodology for Strategic Environmental Assessment of urban areas in Latin America based on the recently approved European Planning Directive, and applies it to the Metropolitan Area of Concepción (Chile). The method is based on the Land Suitability Index (LSI), a cartographic GIS-based index originally developed for the region of Barcelona (Spain) and aimed at determining the suitability of each point in a region for urban development, considering three sub-indexes: (i) Naturalness, (ii) Ecological Connectivity and (iii) Natural Risk. Using the LSI we evaluated the already approved urban plans of the municipalities in the region, considering two scenarios: the initial land use or baseline scenario (S0) and the designated land use or planned scenario (S1). The results show that overall the planned scenario will result in a loss of around 16% of naturalness, with particularly negative effects on brushwood and wetland areas. Connectivity will decrease by around 17%, and urban areas exposed to many types of natural risks will increase considerably, from approximately 49% to 92% of the total urban surface. Finally the LSI shows that around 252 ha are suitable for new urbanization in the extension area. This corresponds to around 0.7% of the total extension area (37.381 ha), which represents 12% of the region (271.398 ha). We propose this methodology can be a valuable contribution to the design of Strategic Environmental Assessment applications and indicators for land planning in Latin America.

Strategic Environmental Assessment (SEA) has been a mandatory land planning procedure in Europe since the approval of the Directive 2001/42/EC, on the assessment of the effects of plans and programs on the environment. SEA is the process by which environmental considerations are required to be integrated into the preparation and adoption of these plans and programs in order to promote environmentally sustainable development (Jiricka and Pröbstl, 2008). In consequence, SEA will contribute to the reduction (or avoidance) of the environmental, social and economic costs often associated to excessive or chaotic urban growth (Portal and Béjar, 2005 and Botequilha-Leitão and Ahern, 2002). SEA is inspired by two objectives: (1) to overcome the insufficiencies of Environmental Impact Assessment (EIA) by evaluating projects earlier in the decision making process and (2) to emphasize the importance of a territory's limitations and opportunities by defining the options of sustainable development. While being a more general procedure than project-specific assessment instruments such as EIA, it poses significant challenges for decision making (Unalan and Cowell, 2009). A particular challenge of SEA is how to adequately integrate all the dimensions of sustainable development so that it becomes an achieveable, practical objective, which can thereby incorporate the environment into policies, plans, and programs (Oñate et al., 2002). A particular focus of application for SEA is urban plans for metropolitan areas. Currently, more than 3 billion people are living in urban areas worldwide, and this figure will have increased to 6.4 billion by 2050 (United Nations, 2009). A critical feature of this projection is that the largest population growth expected in urban areas will be concentrated in the cities and towns of developing regions (United Nations, 2009), such as Latin America. However, these overpopulated metropolitan regions still house important natural areas featuring considerable ecological diversity, and providing ecological services to the population. There is, therefore, an urgent need to rethink the appraisal of urban plans and projects to consider metropolitan areas as a mosaic for natural systems and population. It is paramount to combine traditional urban planning that emphasizes quality of life, with conservationist planning that focuses on the conservation of ecosystems and biodiversity (Forman, 2004). In Latin America, a number of countries are progressively incorporating a SEA rationale via EIA, environmental frameworks and environmental mainstreaming in policies and plans (Sánchez-Triana and Quintero, 2003). In the case of Chile, the Environmental Impact Evaluation System (SEIA), detailed by the Environmental Law (1994), states that land planning instruments have to incorporate environmental impact studies in their approval process. Additionally, EIA regulations state that environmental assessment must be present from the project's beginning and the predicted scenario must be monitored to see if the environmental changes have been effectively minimized or avoided. However, these evaluations are frequently performed considering the impacts produced by each project or initiative and not with respect to the overall territorial model as required by SEA (Suazo et al., 2009). In consequence, the EIA process in Chile does not sufficiently ensure the conservation of natural systems in metropolitan areas that are subjected to strong urbanizing pressures (83% of the population lives in urban areas; MINVU, 2008). In southern Chile, urban regulating plans for the coastal cities of Tomé, Penco and Coronel approved by the SEIA promote urban development in areas with a high risk of flooding or landslide (Suazo et al., 2009). Thus, the current urban growth regulation poses serious environmental and security challenges in metropolitan areas of Chile, because the norms are focused towards specific projects, while SEA embraces a wider view trying to protect and enhance the natural environment, integrating social and economic factors alongside environmental qualities (Wallington et al., 2007). Thus, we consider SEA is a more adequate assessment tool that favors the integration of impact assessment and sustainable urban growth in metropolitan areas of Chile. One of the main difficulties of applying SEA is that many regional plans frequently fail to take environmental factors properly into account (Marull et al., 2007). Quantitative socio-environmental indices, already in use for aquatic systems (Paul, 2003), may be a good choice to assess the impact on land of diverse alternative plans (Lugeri et al., 2000). Indeed, a number of interesting applications have been developed on the interface between landscape ecology and urban planning principles (Botequilha-Leitão and Ahern, 2002, Opdam et al., 2002, Corry and Nassauer, 2005 and Termorshuizen et al., 2007). However, such approaches have not provided significant advances in perhaps the most important constraint of these methods: the lack of standard methodologies. The recently developed Land Suitability Index (LSI) aims to overcome this challenge and has been used to evaluate the adequacy of land for urban development in the region of Barcelona (Spain) in the SEA context. It combines three main sub-indices concerning (i) the vulnerability of the biosphere, lithosphere, and hydrosphere to impacts arising from implementing the predevelopment proposals; (ii) the natural heritage value of the target area; and (iii) its contribution to terrestrial ecological connectivity (Marull et al., 2007). The development of these methodologies and their application to SEA might be, however, affected by data quality and availability (Marull et al., 2007 and Desmond, 2007). In particular, spatial and thematic accuracy of cartographic datasets might have non-negligible effects on the SEA results and their consequences on decision making. Therefore, it might be desirable to generate statistically valid estimates of the accuracy of these maps, e.g. describing their misclassification errors (Nusser and Klaas, 2003 and Serra et al., 2003). However, the effects of data quality on uncertainty have been explored only recently within SEA context (João, 2007), together with other uncertainty sources affecting it (João, 2007). SEA is generally seen as a process dealing with highly diverse data sources and societal values, and supporting great flexibility in its expected outcomes (Partidário, 1996, Partidário, 2007 and OECD, 2006). Thus, it is assumed that data quality should not preclude the application of SEA but only modulate its expectative. This paper aims at incorporating SEA principles into the assessment of the Plan for the Metropolitan Area of Concepción (Central Chile) based on the Land Suitability Index developed for the Metropolitan Area of Barcelona (Marull et al., 2007). The original methodology has been adapted to the general Latin-American scenario, characterized by low availability of reliable GIS data. We present the method developed and tested in the Metropolitan Area of Concepción (Chile), which focused on the evaluation of ecological functionality and natural risk for the population, and was based on a limited number of GIS layers. Using this methodology, we have determined (i) the expected changes in environmental dimensions (natural heritage, natural risk, and ecological function) under the plan application and (ii) the suitability for urban development of the planned areas, based on these dimensions.

This paper provides a preliminary approach to the appraisal of planning instruments in Chile, based on the SEA rationale through a modification of the LSI proposed by Marull et al. (2007). The LSI is related to the concept of hosting capacity, generally understood as a territory's aptness to support distinct land use (Marull and Mallarach, 2005 and Otero et al., 2006). The application of an ad hoc version of this index in the CMA thus provided a first evaluation the land's aptitude to support urban and infrastructure development in the CMA based on physical and ecological parameters such natural heritage, geotechnical risk, and ecological functionality. This evaluation could help to improve the dominating land planning criteria based on population demography, socioeconomics, and mobility (Malczewski, 2004). Despite Chile having a specific plan appraisal tool (SEIA), there is a growing consensus that the application of the SEA rationale might help to improve the sustainability of some derivatives of Chilean zoning plans and programs, e.g. in urbanization processes. Indeed, the contribution to sustainable development of regional and local planning instruments in Chile is, nowadays, very limited. The MUPC is a general normative framework for local planning that provides a restricting approach especially as regards as zoning natural value areas. Indeed, in their Articles 2.1.17 and 2.1.18, the General Law of Urbanism and Construction (Chile Government, 2008) only considers as protected land those zones that are already protected by the competing institution, the National System of Protected Wild Areas (Sistema Nacional de Áreas Silvestres Protegidas). Local urban planning frequently has to restrict residential use in areas not necessarily designed for environmental conservation, and thus planning instruments have acquired more competencies than those assigned by the Law. A key limitation of plan and project appraisal in Chile is the lack of clearly identifiable indicators and comprehensive methodological frameworks for their use (Portal and Béjar, 2005). The development of SEA indicators might be, in turn, constrained by the availability and quality of environmental cartography. Our modified version of LSI was aimed at overcoming these difficulties using generic environmental mapping that might be obtained with relatively limited resource, in order to facilitate the application of the method across the Chilean metropolis. However, even so, some constraints remained in the case of the CMA. First, land cover cartography was not up-to-date enough, despite the most dynamic categories (i.e. urban areas) were updated to 2001 and thus were quite contemporary with the start of the MUPC (2003). Second, information about its accuracy (e.g. Kappa indices) was available for our classification of urban areas in 2001 but not for the main land use map by CONAF et al. (1999). As no error values could be provided when assessing the distribution and changes of our SEA indexes, figures have to be considered approximate and mostly indicative for the average status and trends in the region, especially for the most quantitative ones (ECI). However, it should be taken into account that the MUPC is not completed, and how it will be carried out in the near future might add a greater bias in our results than that arising from data inaccuracy. Moreover, the use of few land cover categories might help to reduce the misclassification effects in these indices. In the case of LSI, the scaling of its components into ordinal categories might help to reduce these effects. We then conclude that the potential constraints in land cover data accuracy and updating would not invalidate our SEA results but modulate their expectative. Still more important are the constraints derived from data availability regarding natural risks. These risks have only been considered in their whole for the coastal sector of the CMA, which is the most populated in the region and it is potentially affected by recurrent flooding and tsunami, especially in the ocean shoreline and in the Bio Bio margins (Mardones and Vidal, 2001). Coastal flat areas also are locally affected by wind deflation, which might pose in risk several human settlements close to dune areas. In contrast, the risk map for the inland rural sector only considered landslide, through a very simple approach due to the lack of key information on soil and surface lithological formations. While this approach is supported by the landslide risk matrix suggested by Mardones and Vidal (2001), some field assessment of the resulting risk map through ground control areas should be done in the future. This risk map did not include the flooding or the tsunami risks of rural areas, which are concentrated in the coastal area but that might affect the Bio Bio margins in some in land areas. It neither included the wind deflation risk that is a typically coastal process. Therefore, the assessment of natural risks in the CMA needs to be improved with more reliable methods and more complete and up-to-date cartography, as recently discussed in the context of the earthquake of 2010 (Romero et al., 2010). In any case, the methodology provides a first quantitative assessment of the application of the MUPC in SEA context. Our study based on the LSI identified negative trends in the three dimensions analyzed in the CMA: (i) high overall impact, (ii) planned urban development in highly valuable and risky areas and (iii) impact on the ecological functionality of protected areas due to land transformation in their surroundings. These trends are in agreement with the local increases in large irrigation areas in the coastal cities of the CMA (Suazo et al., 2009), suggesting that the planned urban growth is highly unsustainable since the new urban areas will necessarily occupy lands that require protection because they are susceptible or sensitive to natural risks. In short, the proposed land use plan does not correspond to the territory's physical capacities. Therefore the majority of unsuitable areas were classified as rural zones and these are still considered extension areas (i.e., reserves for future growth) for the city and will be used once the extension areas neighboring the built up areas become urbanized. Human population in the CMA is concentrated in medium-sized cities located on the coast, which is associated to a natural dynamic influenced by conditioning factors of steep slopes and river mouths that are very vulnerable to urbanization urban expansion. In recent decades, the CMA has been characterized by an intense, simultaneous urban sprawl, dominated by growth in the periphery with a disperse pattern through road infrastructures (Rojas et al., 2009) and with principally negative impacts on the natural ecosystem (Pauchard et al., 2006). The future scenario model or urban planning model will not change much even when it does not permit urban settlement in the higher valued natural areas, which at present are especially affected by urbanization (Pauchard et al., 2006 and Villagran-Mella et al., 2006). Additionally, the CMA is overflowing into areas that are difficult to handle and are exposed to strong natural risks, increasing the probability of environmental hazard (Mardones and Vidal, 2001). The impacts on connectivity are principally reflected in the fragmentation of natural areas and, especially, in habitats of high conservation concern. Paradoxically, the connectivity of semi-natural habitats like prairies, which are the outcome of secular human intervention and have lower conservation concern than the remaining natural habitats, might increase in the future scenario. Also, it should be noted that the MUPC contemplates extensive land development, which corresponds to more than 20 times the growth needs estimated by Baeriswyl (2007). Consequently, this extensive urban development is not justified, even considering the 20% population increase estimated for the year 2020 (INE, 2008). Moreover, this high urban development will cause important losses in naturalness and ecological connectivity; however the highest losses are relatively acceptable due to the low naturalness of categories (bare soil and lumber plantations). The protected areas included in the plan will become natural islands in an urbanized matrix because no ecological corridors are contemplated in the MUPC. If the proposed scenario (S1) is implemented, the CMA will face serious impacts on its ecological function and mechanisms must also be implemented to diminish the possible negative tendencies produced by the planned urbanization. The decrease in ecological connectivity within protected areas where no urban development is planned is an unexpected result that deserves special attention. It can be interpreted as an extrapolation to the land planning scale of the statement by Janzen (1983) ‘no park is an island’. Clearly, the ecological connectivity of protected areas will be highly affected by changes in the surrounding land use and land cover categories. Thus, ecological networks should be considered by selecting corridor areas that maintain or increase connectivity between protected areas, although the inclusion of areas and corridors cannot be used to mitigate unsustainable development in the surrounding land matrix. Agricultural areas play a complementary role to natural parks in maintaining biodiversity in metropolitan regions (Santos et al., 2008). Sustainable development will, then, require a regional policy aimed at increasing landscape heterogeneity and evaluating rural landscapes in terms of ecological services (such as biodiversity maintenance) as well as economic value. It should be noted that the proposed methodology for adapting SEA to the Chilean case cannot replace the environmental impact evaluation required by Chilean Law (SEIA). However, it does provide a complementary assessment using a prospective approach that considers the sustainability of future land use. Also, the indices put forward do not disqualify the Plan's proposed zoning because their objective is evaluative and not normative. Rather, this evaluation aims at promoting discussion and reflection with respect to how planning can be improved in order to revert negative tendencies of unsustainable urban development. The incorporation of these findings corresponds to political decisions and policy makers.