ABSTRACT
CONTENTS 19.1 Introduction ............................................................................................. 387 19.2 Background.............................................................................................. 388 19.3 A Case Study of ISA and Aquatic Fauna-The Line Creek
Watershed, Atlanta, Georgia, United States....................................... 389 19.3.1 Introduction ............................................................................... 389 19.3.2 Derivation Techniques and Algorithms to Determine
ISA Delineated by Watershed................................................. 390 19.3.2.1 Watershed Delineation ............................................ 393 19.3.2.2 Data Masking............................................................ 394
19.3.3 Peachtree Watershed ISA and Freshwater Mussel Diversity ....................................................................... 395
19.4 Further Studies of ISA and Aquatic Ecology..................................... 399 19.5 Discussion and Conclusions ................................................................. 403 References ........................................................................................................... 405
Human activity in the shape of land-cover and land-use change, in particular urbanization, is often cited in the literature as a major factor contributing to a staggering loss in ecological biodiversity. So much so, that The National Academy of Sciences has noted the ecological impact of land-cover and land-use change (NRC, 2001). Urbanization is persistent in the sense that it is a more lasting type of land-use change than are other types of habitat loss; moreover, it continues to expand geographically with resulting effects on the environment (Benfield et al., 1999). In the United States, the data on species loss reveal themselves in the increasing number of plants and animals added to the endangered species list. As an indicator, however, it
is misleading and frequently understated, as knowledge of extinctions along with inventory lists are better for some species than others. In the context of aquatic environments, for example, the knowledge base for freshwater fish and bivalves* is quite extensive (USEPA, 2002; Nilsson et al., 2003) while those for other water settings (i.e., bed landscapes of water bodies), which harbor abundant biota, are sorely lacking.
