3. A case study in TaiwanTaiwan is an elongated island, measuring some 370 km inlength and 130 km at its point of greatest width, which lies of thesouth-east coast of China (Fig. 2A). The geography of Taiwan is char-acterized by its mountainous topography, with approximately 70%of its land area having slopes that exceed 15% (Fig. 2B). Two hundredand fifty-four (254) administrative units along Taiwan’s westerncoastal plain were identified as the study area. These units are lessthan 200 m in elevation and have slopes less than 5%. The west-ern coastal plain is the most densely populated area in Taiwan.From 1971 to 2010 this region increased in population from 12.7 to21 million. The area contains nearly 92% of the total population inTaiwan. As shown in Fig. 2C, the population density of many of the cities in Taiwan’s western coastal plain (over 1600 persons/km2)is much higher than the average population density of Taiwan(711 persons/km2). In addition, 90% of all the urban-planned