1	Biological Assessment Chapter 7
2	Biological Assessment There are many types of life in a stream. Biological indicators - species that cannot survive ecological or environmental degradation. Non-tolerant Environmental thermometer A wide variety of plants and animals living in a stream usually indicate a healthy environment.
3	Benthic Macroinvertebrates Benthic - bottom dwelling Macro - large enough to see Invertebrates - animals without a backbone Most common way to assess biological health of a stream. Biotic index - the number and types of organisms found
4	Collecting BM
5	Habitats and Microhabitats It is very important to sample all microhabitats You want to collect a representative sample of what types of critters are living in your stream Record on your datasheet which habitats are sampled Record on you datasheet which microhabitats were present and which ones were sampled
6	Vertebrates Animals with backbones. Fish are the most common used to assess a stream. For more information on documenting vertebrates see the section in Chapter 16 on NatureMapping.
7	Benthic Macroinvertebrates vs Vertebrates Benthic Macroinvertebrates They don’t migrate They are easy to collect and identify They have known tolerance levels Vertebrates Migrate long distances Collecting and identifying is difficult, expensive and time consuming Some are state and federally protected
8	Aquatic Plants Plants that grow in water and in saturated soils. They are difficult to identify. Amount of information on tolerance levels is small. In general aquatic plants are indicators of good water quality. They provide habitat and reduce soil erosion.
9	Algae Small photosynthetic organisms. Many require a microscope to identify. A high nutrient load can produce excess algae. This can lead to oxygen depletion and the death of aquatic organisms. Some algae can cause odors, foul tastes, and toxic by- products.
10	Grey or sewage algae Actually filamentous bacteria Create strings of colonies that can be seen with the naked eye. DO NOT wade in this stream!
11	Bacteria Microscopic single celled organisms. Can be indicators of pollution. Coliforms, E. coli, Enterococci Species that usually are not harmful to humans but are often found with pathogens. Pathogens are disease-causing organisms. It is a good idea to always wash up after monitoring.
12