Course Progress

NSI

Topics Covered

• Logic– Reasoning and Evidence

• Sampling– Bias, variance and making inferences

• Statistics– Making probability statements for 3 types of data

comparisons

• The nature of science – Hypotheses, refutability, expert opinion

The scientific methodObservation

Design test

Conduct test

Manage & analyze data

Reject or accept hypothesis

Interpret results

Communicate findings

Hypothesis

?

The scientific method

Manage & analyze data

Interpret results

Design test

Conduct test

Reject or accept hypothesis

Communicate findings

Observation

Hypothesis

?

Next steps…

• 1. Critical analysis and exposure to science-related issues

• 2. Formulate a hypothesis and design a study to test it

• 3. Integrate all aspects of the scientific method into your final project

Water quality in stream ecosystems

A complex system

The Systems Approach

• A system is any phenomenon having at least 2 separable components and some interaction between them.– Properties:

• 1) They are modular, i.e. can be separated into components

• 2) They are hierarchical, i.e. each system is part of a hierarchy of other systems

stream 1 ecosystem

bioticabiotic

plantsfisharthropodsexternal factorsH20 quality

stoneflymayfly

individual 1 individual 2 Individual k…..

streams

stream k ecosystemstream 2 ecosystem

wetlands lakes forests

wilderness area

…..

Micro-organisms

caddisfly

temp pH dissolved particulatesmicro- macro-

“Each level finds its explanation in the levels below, and its significance in the levels above” -Bartholomew

beetle

• Once the components are identified, we can then create a model of how the components of interest are related.– A model is any representation (simplified) of a

real system.– Models are used for:

• 1) Understanding• 2) Prediction• 3) Management

Building a simple model

MacroarthropodsAlgae Fish

Fertilizer run-off

..…levels of resolution

Herbivorous insectsAlgae Fish

Fertilizer run-off

Predatory insects

Streams drain watersheds

Channel & Riparian Zone

ThermalChemical

Water Quality

Particulate

pH Dissolved compounds

Temperature Dissolved gases (*O2)

Turbidity Microbes

Erosion SewageIndustrial discharge

Household discharge

Agriculture Exposure to the sun

Riparian zone management

Pollution

Bio-indicators: “EPT Diversity”

Ephemeroptera

(mayfly)

Plecoptera

(stonefly)

Trichoptera

(caddisfly)

Other potentially useful bio-indicators:

• Odonata: dragonflies & damselflies

Other potentially useful bio-indicators:

• Water mites (Acari: Hydrachnida)

A giant water bug infested with water mites

Larval Attachment:

• A resilient, accordian-like “stylostome” is cemented to the host cuticle and serves as a feeding tube.

• 300-600 X volume increase!!!

Photo from Abro (1984)

Other common (and more tolerant) aquatic insects

Coleoptera

(beetles)

Hemiptera

(true bugs)

Diptera

(true flies)

Summary

• 1) Breaking down complex systems into manageable components

• 2) Creating a model consisting of components and relationships between them

• 3) Using aquatic arthropods as biological indicators of water quality

Rain Beetle

Field trip (Monday / Wednesday)

• Rain or shine!• Bring:

– warm clothes – rain gear– something to write with & something to write on

• Vans leave at 9am sharp(!), between Cramer and Smith Halls (on Broadway).

References

• Hall 1997. Ecosystem modeling in theory and practice: an introduction with case histories. Wiley & Sons, NYC

• Orians 1980. Micro and Macro in ecological theory. BioScience 30: 79

• Walters 1971. Systems ecology: the systems approach and mathematical models in ecology.

• EPA 1997. Volunteer stream monitoring: a methods manual. Available Online, http://www.epa.gov/volunteer/stream/index.html

• Photos: Several websites including Ken Gray Insect Photo Gallery, http://www.ent3.orst.edu/kgphoto/showall.cfm