indicator species, scientists can determine how changes in the environment are
likely to affect other species that are more difficult to study.
Human activities that alter a watershed and interfere with the natural
processes of a stream have immediate as well as long-lasting effects on the
animals that live in that stream. Freshwater macroinvertebrates in a stream
provide the best indicators of that stream’s overall health and ecological
condition.Freshwater macroinvertebrates represent an enormous diversity of body
shapes, survival strategies, and adaptations. Many of them require clear, cool
water, adequate oxygen, stable water flows, and a steady source of food in
order to complete their life cycles. In turn, they provide food for trout,
salmon, herons, kingfishers, and higher trophic levels in the food chain. High
biodiversity (or taxa richness) indicates a healthy site with low human
influence.(d) Maximum 2 points Provide a specific example of an indicator species that
lives in a freshwater or riparian ecosystem (1 point maximum) and how it
functions in its role as an indicator species. (1 point maximum) Freshwater
macroinvertebrates such as stoneflies, mayflies, and caddisflies are some
examples of indicator species that live in freshwater or riparian ecosystems and
are good indicators of a stream’s overall health and ecological condition.
Stoneflies spend the majority of their lives as nymphs. Many species require a
high concentration of dissolved oxygen and are found in clean swift streams with
gravel or stone bottoms and their presence indicates relatively high oxygen
content in the water.
(e) Maximum 1 point ALL boxes must have at least one connecting arrow and no
points are earned if ANY arrows are incorrect. (1 point maximum)