Stream Ecology 530

Final Exam – Fall 2003

Directions:  In taking this exam, you are limited to your textbooks and lecture notes (Class notes/handouts & course web-page).  Limit your answers to no more one page (double-spaced) per question.

1.  In the Pacific Northwest , the light and temperature regimes of streams differ greatly between old growth forests and recently harvested forest stands. Describe how the relative abundance and distribution of periphyton, macroinvertebrates and native salmonids may differ between these forest environments.

2.  Define voltinism and its potential role in maintaining diverse assemblages of aquatic macroinvertebrates in streams and rivers.

3.  As an aquatic ecologist with the National Oceanic and Atmospheric Administration, you are interested in studying the role of marine-derived nutrients (MDN) in the food webs of regulated and free-flowing coastal rivers of the PNW.  Briefly describe why the use of stable isotopes would be a critical component in your study design.

4.  Recent studies have shown that the stable isotopic signatures of carbon may differ between riffle and pool algae.  Briefly explain the mechanisms influencing the stable isotopic composition of benthic algae and their significance in stable isotopic studies of stream food webs.

5. Compare/contrast the primary factors influencing the selectivity of prey items by aquatic macroinvertebrates and fish.

6.  Describe the basic differences and predictions between two general circulation models ~ GISS and GDFL ~ for annual and seasonal runoff patterns in western North America .  On the basis of these models, compare/contrast the potential consequences of climate change for river biota in the Columbia River Basin .  

7.  Many studies have documented the impacts of regulated flows on the ecology of rivers.  Provide a brief overview of biotic responses to regulated flows and some potential approaches for managing regulated flows to promote the biodiversity of native river biota. 

8.  In restoring normative flows to regulated rivers, why is it critical to mimic natural rates/patterns in the rise and fall of river stage?

9.  Compare/contrast the role of invertebrate drift in the ecology of neotropical and temperate streams.