Environmental Systems

1. Environmental Systems Measuring Biotic and Abiotic Components of a System 2.1.1, 2.3.1-2.3.5, 2.7.1-2.7.3

2. Biotic = Examples: Abiotic = Examples Biotic vs Abiotic (ie physical) components of an ecosystem

3. List the variable abiotic (physical) factors of an ecosystem • Marine • Freshwater • Terrestrial

4. Describe & Evaluate methods for measuring abiotic (physical) components • Precipitation: rain gauge • Temperature: thermometer • pH: pH strip; pH probe • wind speed: aerovanes • Dissolved Oxygen: DO Probe or chemical test • Salinity: Hydrometer

5. Describe and use methods for estimating abundance of organisms • Quadrat - A quadrat is a frame of any shape that can be placed over vegetation so that species can be listed or counted, and population density, percent frequency and percent cover can be estimated. = For non-mobile organisms • Capture-Mark-Release-Recapture (Lincoln Index) = For mobile organisms

6. Quadrat System of Counting Example

8. Capture-Mark-Release-Recapture (Lincoln Index) • N= the estimated population (what you are looking for) • T1: total organisms you caught and marked in 1st sample • T2: total organisms you captured in 2nd sample • M: the number that were marked in the 2nd sample. (meaning they have been recaptured) • N = T1 x T2 M Example… So, do you have a larger population if you have a large or small “M”? Why?

9. Evaluate techniques • Cap/Mark/Recap: • Only works with a static population…..does this occur in nature? • Marked individuals are more noticeable to predators • Losing their marks by molting, rain, etc • Quadrats: • Limit accuracy by amount of money you have to spend on counters. • Less counters or smaller quadrats mean less accuracy. • Placement of quadrats can cause results to be skewed.

10. Describe and evaluate a method of estimating biomass of trophic levels in a terrestrial community • Biomass - estimate of dryweight in g/m2 of an organism. • Method?

11. Diversity • Three types: Habitat, species, genetic • 2 components: • 1. Richness = # of different species in an area • 2. Evenness = a measure of relative abundance of each species in an area. (number of organisms of each type of specie) • A community that is dominated by one or two species is less diverse than one that has several different species with a similar abundance, even if they have the same richness amount. • Ex?

12. Apply Simpson’s diversity index • A measure of species richness of an area. • A high value suggests a stable, climax community. • A low value could suggest pollution, early stages of succession or agricultural management………Why?

13. Calculation • D= Simpson’s Diversity Index • N = TOTAL # of organisms of all species found. • n = number of individuals of a particular species. • D = N(N-1) Σ[n(n-1)]

14. SpeciesN A 3 B 4 C 2 D 2 E 4 Total = N = 15 N(N-1) = 15(15-1) = 210 (210 is your top number!) n(n-1) 6 12 2 2 12 Σ[n(n-1)] = 34 (34 is your bottom number!) Example

15. Simpson’s Index: D = N(N-1) Σ[n(n-1)] D = 15(14) = 210 34 34 D = 6.17 Is this area diverse? Here is the problem: You CAN’T tell from this equation. All you can do is tell relative diversity when compared to another area/Diversity number ie: This area would be less diverse than an area whose Simpson’s Index number is 10. Only used for comparative purposes Example Con’t

16. Describe and evaluate methods for measuring changes in abiotic and biotic components over time • Rainfall = rain gauge • Temp = thermometer • Species diversity = quadrats or mark and recapture and then Simpson’s Diversity Index • Species abundance = quadrats or mark and recapture • All of these stats would be taken over a set amount of time………..mutiple data sets (at least 2....when?)

17. Environmental Gradient • What is a gradient? • Therefore an environmental gradient is a change in abiotic or biotic factors over an area. • Examples of where you can see this? • How should you measure this?

20. Describe and evaluate methods for measuring changes in abiotic and biotic components of an ecosystem due to specific human activity • YOUR LABS DO THIS!! • Examples of human effects and how to measure them? • Could also include satellite images and maps.

21. Describe the use of Environmental Impact Assessments • An EIA is a government report prepared before a development project that will change the use of land (in the planning process). • Ex: major new road networks, airports, building power stations, dams, quarrying, planting a forest, converting fields to a golf course, large-scale housing projects, etc. • The EIA weighs up the relative advantages and disadvantages of the development. • It will try to quantify how the abiotic and biotic factors would change if the development occurs. • Therefore, a baseline study is necessary first....what the environment is like now. • The EIA will forecast both negative and positive impacts on the natural environment and human populations (if the development might have an effect on human health or a community’s economy).

22. Evaluate EIA’s • EIA’s measure the social and environmental costs of the development and tries to translate these into monetary values. • Ex: number of jobs provided, net profit of the development, land degradation, habitat loss, pollution, human health, etc. • What issues can there be with many of these assessments?

23. Construct simple keys and use published keys for identification of terrestrial organisms (Dichotomous Keys) • Homework: • Find pictures of or draw 8 organisms and print them out. • Make a dichotomous tree and then a key • On a third sheet of paper, print the pictures out again and make an answer key.