The tolerance level of the ecosystem as a limited constrain in the development planning

Abstract

There are several methods for assessing ecosystem tolerance level, each method is defined according to the target of the ecosystem development. This paper seeks a way to plan for the development of the existing ecosystems modified for human activities. For this purpose, two methods have been applied to assess the effects of local development on the local ecosystem tailored to the different demands. Thus, after gathering data in a coastal region all technologies being capable to be applied in this region regarding ecotourism development (population growth) were determined. Via different indicators, the quality of the ecosystem was evaluated. The Ecosystem Quality Index (EQI) and Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) are methods of decision making. Both methods were applied to minimize the negative effects of the development plan. These methods have similar behavior against development. In the context of decision-making, a minimization method was used so as to minimize the distance between the values of the indicator in the current and future time horizon in the EQI method. The second method; that’s to say, minimization of negative effects is the main target to choose the technology.In the present paper, Shif Island, as a certain limited region in the south of Iran, has been investigated. In this region, industrial development might directly affect the soil and water quality and it might disrupt the development of agriculture and the natural ecosystem. In this regard, local development might have restrained the availability of resources and also might have a detrimental effect on the environment. Population growth has been one of the main pressures on the ecosystem. If the economic development of the island is aimed at the expansion of ecotourism, it shall have both positive and negative effects on the local population. The development of the wastewater treatment system in Shif Island would lead to an increase in the tolerance level in 2025. Since 2018, due to the development of industrial and rural facilities, Soil erosion has been observed. After 2027, the tolerance level will be increased. Extension of the organic phase of soil and accumulation of biomass also will improve the quality of the soil.The application of two methods and analysis of variation of ecosystem tolerance has indicated that a decreasing trend of ecosystem tolerance should be expected until 2027. Then, a steady increase in ecosystem tolerance will be observed from 2028 onwards and will go on in the years following then.