Urban Stream Discussion Part 1

I focused on the first set of questions that were directly related to the reading from the discussion led by Ben and myself on urban streams.

As indicated in the reading, why may have previous studies demonstrated that effective impervious area (EIA) is a “better” predictor of stream biological and chemical response than total impervious area (TIA)?

-Effective impervious cover area is impervious cover which is directly connected to a stream. For example, a parking lot that is directly adjacent to a stream. Where as total impervious area includeds all the impervious surfaces such as sidewalks. Therefore, EIA is a stronger indicator for the effects of impervious cover on a stream

2. What is the importance of understanding the historic land cover of an area for predicting current fish assemblages of a stream?

- Understanding the historic land cover of an area is important for predicting the current fish assemblages of a stream because the historic land use could have already degraded the habitat and affect the fish assemblages, such as impoundments could have lead to the populations not being able to be restored to historic population numbers and the introduction of new fish species.

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3. Why might historic land use predict abundance of one fish species but be a poor predictor of another?

-Because the fish that was used in the study, E. scotti, did not show a change in abundance with urban areas as compared to the forested areas.

4. Why might hydrogeomorphic models be a poorer predictor compared to the impervious cover area models for the species used in this study?

- Its not that they are necessarily poor indicators. Often the effective impervious cover influences these indicators as well.

5. Why do you think the species chosen for this study were used as indicator species?

-They are limited in range and are not found abundantly over all. Also, they are fairly sensitive to changes in the geomorphologic processes,

6. What are some indicators of historic land use and how can these be applied to understanding the historic land use?

- Impoundments and reservoirs are fairly good indicators of historic land use.