| River ecosystems cannot be isolated from landscape-scale influences. Therefore, a more accurate understanding of the effects of urbanization on river ecosystems is necessary to develop effective aquatic management plans. A complete review of all resources available to urban planners indicated that deficiencies exist in regulations, institutional organization, and ecological information that may limit successful planning for landscape scale changes in regions with urbanizing stream ecosystems. In order for urban planners to consider values that ecological resources contribute to the urban context, they must: (1) understand the scale and process of ecosystem response to disturbance; (2) coordinate the review process between local, state, and federal governments; and (3) incorporate scientific knowledge into management decisions. Urban land use in the river city of Indianapolis, Indiana, was expanding outward and upward into tributaries, guided by topographical and social forces, as indicated by permits issued for construction in a floodway. This pattern may have predictable negative effects on stream ecosystems. As a concentric circle of urbanization expands outward from a central location on the mainstem, fish populations in outer tributaries may be separated from mainstem fish communities by barriers due to degraded habitat and water quality. Management planning in urban areas requires tools for prioritizing streams for protection and restoration. Biomonitoring indices were useful in distinguishing major effects of rural, suburban, and urban land use in metropolitan Indianapolis on stream habitat and fish communities in 13 tributaries of the West Fork of the White River. The Qualitative Habitat Evaluation Index (QHEI) suggested that instream cover and pool habitat were lacking and channel morphology was degraded in urban areas, whereas substrate quality was negatively correlated with open undeveloped (unforested, abandoned or agricultural) areas. The Index of Biotic Integrity (IBI) demonstrated negative effects of urbanization on darter species, insectivorous species, simple lithophilous spawners, and sensitive species. UrbanFish, a prototype computerized decision support tool was designed and tested for its utility in predicting the effects of floodplain construction on stream ecosystems. Development of a completely functional system would require advances in computer technology, ecological knowledge, and modification of biomonitoring indices. |
