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)

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

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

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

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

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

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).

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

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

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.

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

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)

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

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

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.

Environmental Impact Assessment of Iron ore mining in Goa through Remote Sensing. (Sponsored by the Ministry of Environment & Forests, Govt. India, Principal Investigator)(1988-92)

OverLay method