1. Assessment Statements
2.7.1 – Describe and evaluate methods for measuring changes in abiotic and biotic components of an ecosystem along an environmental gradient
2.7.2 – Describe and evaluate methods for measuring changes in abiotic and biotic components of an ecosystem due to a specific human activity
2.7.3 – Describe and evaluate the use of environmental impact assessments (EIAs)

2. Environmental Gradient
A trend in one or more abiotic and/or biotic components of an ecosystem
Examples found at shores of lakes, streams and seas and at forest edges
Measurements most easily done on vegetation or immobile animals
Ex: Toxins from mining, landfills, eutrophication, effluent, oil spills, overexploitation

3. How to measure? - Transects
Line transect: simplest version
String or measuring tape laid out in the direction of the environmental gradient
All species touching the string or tape are recorded and counted
Normally many line transects need to be combined in order to obtain more accurate results.
Belt transect:
Strip of chosen width through the
ecosystem.
Lay down two parallel line transects
(±1m apart) between which
individuals are counted.
Transects can be continuous or interrupted

4. METHOD:
Interrupted line transect with stations at specific altitudes
Several repeats at the same altitude, same hour and same day of year to make sure the only factor that varies is altitude
monthly measurements could be taken in the same way over a year in order to observe seasonal variations in the same station

5. EVALUATION OF METHOD:
This method is highly reliable provided several measurements are taken repeatedly at the same altitude making sure they all are taken at the same hour of the day and on the same day of the year
Measurements made over several years in the same way may provide very consistent data and evidence variations over decades
The reliability of the data collected depends on the calibration and the accuracy of the instruments used and the expertise of the persons that carries out the measurements

6. Line transects along the shore of a lake
Several quadrats dropped (S) at specific stations specific distances from the edge of the lake and moving into the forest area following transect lines (T)
In each of the S1 stations the quadrats are dropped to measure any of the following factors of ecological parameters:
soil humidity level
organic matter
nitrate, phosphate and potassium contents
soil pH
percentage cover by herbs, shrubs and trees
biodiversity of plants among other ecological parameters such as biodiversity of insects.
Measurements taken from the same station number are averaged and the averages are plotted against distance from the edge of the lake.
Method: Assessing soil water content gradient
Edge of lake – wet and young soil
Further from edge – water content decreases, soil is older

7. In the above exercise, insects were monitored every two years by scientist in an experimental station located at 1000 metres above sea level in the Central Peruvian Highlands (Antioquia).

8. Environmental Imapct assessments (EIA)
An EIA is a system of identifying what the effects might be on the environment and man from any major development and a way of presenting that information so that it can have an affect on the future of the development.
Includes
Baseline study before development
Assessment of possible impacts
Monitoring of change during and after development

9. Environmental Imapct assessments (EIA)
EIA’s are most often a form of survey made before a major development starts.
They look at what the environment is like now and forecast what may happen if the development occurs.
Both negative and positive impacts are considered as well as other options to the proposed development.
Promotes sustainable development by identifying environmentally sound practice and mitigation measures for development

10. Environmental Imapct assessments (EIA)
What developments need an EIA?
The developments that need EIA’s differ from country to country, but certain types of developments tend to be included in the EIA process in most parts of the world.
But they include:
Major new road networks
Airport and port developments
Building power stations
Building dams and reservoirs
Quarries
Large scale housing projects.

11. Environmental Imapct assessments (EIA)
History
1969 – National Environmental Policy Act (NEPA)
Federal agencies had to consider the natural environment in any land use planning
This gave the environment the same status as economic priorities

12. Environmental Imapct assessments (EIA)
Stages of an EIA
Is an EIA needed and which impacts need to be considered (SCREENING)
Identifying impacts (SCOPING)
Predicting the scale of potential impacts
Limiting the effect of impacts to acceptable limits (MITIGATION)

13. Environmental Imapct assessments (EIA)
What do you need to know?
Baseline data – what are the conditions like now?
What effects do different phases of a project cause
Who or what is likely to be affected

14. Environmental Imapct assessments (EIA)
Types:
Checklist
Matrices
Overlays
Cost and Benefit Analysis

15. Environmental Imapct assessments (EIA)
One of the ways to carry out an EIA is by using the Leopold matrix which is a semi-quantitative method pioneered in 1971.
It is used to identify the potential impacts of a project on different environmental, economic, societal and cultural components relevant to an ecosystem.

16. Environmental Impact Assessment of Iron ore mining in Goa through Remote Sensing. (Sponsored by the Ministry of Environment & Forests, Govt. India, Principal Investigator)( )

17. OverLay method