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Published byEverett Gabriel Rich Modified over 8 years ago
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Week 9: IB Biology Monday: G.4.: Conservation of Biodiversity ‘Explain the use of biotic indices and indicator species in monitoring environmental change’ Tuesday: Measurement Techniques: Quadrat measurement Transect Sampling Catch and release methods Biotic Indices Simpson’s Diversity Index Biomass Wednesday: Practical session with Quadrat Sampling and Transect Sampling Friday: Review Sections G.1, G.3, G.4.1 Monday 5.11.12: TEST ON SECTIONS G.1., G.3., G.4.1
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G.4.1: Biological monitoring and indicator species What is an indicator species? Any biological species that defines a trait or characteristic of the environment: – May indicate a particular ecosystem – May indicate a disease outbreak – May indicate pollution – May indicate species competition – May indicate climate change
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Indicator Species – Marine health Oysters and mussels are used as ‘biomonitors’ to assess environmental pollution of coastal waters Mussel Watch!
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Indicator species can indicate an increase OR decline in biodiversity ‘Sentinel Species’ ‘Keystone species’ ‘dominant species’
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Keystone species These are species which have a disproportionately significant effect on their environment Sometimes they are predators Sometimes they are ‘ecological engineers’ Examples: Grizzly Bear, Sea Otters, Sea Stars
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Sentinel species
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Some species can indicate the presence of abiotic factors and/or changes in ecological processes On land, lichens are often used since they are sensitive to sulphur dioxide ‘Bushy’ lichens need pristine air Leafy lichens can survive a small amount of pollution ‘Crusty’ lichens can survive in heavily polluted air Regions devoid of lichens may indicate a high concentration of sulphur dioxide
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Biological Monitoring is frequently used to evaluate marine or aquatic pollution
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Advantages of Biological Monitoring 1.We can detect intermittent pollution 2.A specific change in the Biotic index can indicate a specific type of pollutant 3.Food chains can accumulate pollutants (biomagnification) – particularly in higher trophic levels
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Disadvantages of Biological Monitoring Distribution of organisms may be patchy so sampling must be done carefully Invertebrate organisms tend to be seasonal Some indicator species show tolerance to different pollutants
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Sampling techniques you need to know for IB Biology – Ecology Quadrat measurement Transect Sampling ‘Kick’ sampling methods Catch and release methods Biomass measurement
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Analysis Techniques used in IB Biology Biotic Indices Simpson’s Diversity Index Gross/Net Production calculations* * We will cover Biomass calculations next week
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Which type of Sampling Method is appropriate? How to choose your sampling technique
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Quadrat Sampling How large is the Quadrat? That depends on the region being sampled! 0.5 m 2, 1 m 2 How do we decide where to sample? Random sampling Stratified sampling Systematic sampling
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Quadrat Sampling
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How do we ensure that our data is collected in a ‘random’ method? Random Number Table
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Transect Sampling
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‘Systematic sampling’: Transect Sampling ‘Transect’: a ‘path’ along which the number and occurrence of a species can be counted There are several different transect methods: – ‘Strip/ Line transect’ – ‘Belt transect’
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Belt Transect Sampling is carried out to a strip of fixed width – e.g. 0.5 – 1 m
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Line Transect Sampling Transect Sampling Ssampling is confined to describing all of the organisms that touch the line
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‘Kick Sampling’ Techniques Standard method for collection of aquatic samples
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