Unit 4 Biology Slapton ley research

Abundance- the # of individuals of one species in a particular area

Frequency - the # of samples a species is recorded

% Cover - for plants only - how much of the area you're investigating is covered by a species

Distribution - where a particular species is within the area you're investigating

Random Sampling / Systematic / Stratified

Prevents bias 

Precision - how many decimal places you've got and how well defined a value is

Accuracy - how close to the true value

Reliability - a test that produces the same result on repeated trials 

Succession vegetation

1. Tree fall - leaves seed bank

2. Pioneers - macarangas - adapted to receive maximum sunlight

3. Competition for light

4. Hardwood trees - tall and long lasting so out complete outer trees

5. Stable - for around 200 years

Climatic climax community = oak woodland

Succession Shingle ridge 

1. Wave action - creates a GAP

2. Pioneers - sea spurge (xerophytes - adapted to reduce water loss! hairy leaves, small surface area so less water loss, thick water inside stems )

3. #2 Facilitates legumes / rosette - flat on floor - good against wind and trampling on! The root nodules has bacteria (useful for nitrogen fixing bacteria into nitrates 

4. Grassland - outcompetes other plants that shades out for light

5. Woody shrubs - plagio climax  / sub climax community

Abiotic factors:

• Light intensity
• Humidity
• Wind speed
• Temperature
• Rainfall
• Edaphic factors (soil depth, soil pH, soil moisture - organic matter amount of nutrients)

Biotic factors:

• Competition
• Predation
• Number of organisms 
• Food supply
• Disease
• Parasitism 

Different methods used to investigate different organisms

• Pitfall traps - steep sided containers sunk in a hole - partially open - insect falls on the container + can't escape - protected from rain / predators .. some small predators can enter - eat other insects - affect the result
• Pooters - jars have rubber bungs - 2 tubes stuck on bung - inhale through short tube - time consuming but get large sample .. some maybe missed if not large enough 
• Quadrats - investigate plant populations - square frame divided into a grid - placed on ground at different points (species frequency  # of individuals + % cover - quick but subjective)  different size of quadrats
• Transects - use lines calle dtransects - find out the distribution of plants (line transects - tape measure along a transect - touch the tape measure recorded, belt transects - quadrats placed next to eac other along transect + interrupted transects - measurements at intervals)
• Beating trays - used to investigate insects found in vegetation - beating tray / sheet held under a plant / tree .. plant / tree is shaken - insects falls onto beating tray - take large samples - good estimate of the abundance but maybe not random 

Independent Variable 

• Centre vs Edge
• Valley bottom vs top
• south / north facing

How data will be collected

• For ground flora = % cover quick but subjective
• think about the size of quadrat
• gridded quadrat? 
• will it destroy the habitat ?
• For leaf litter - grab sample 
• sample size? 
• will you keep altitude the same? 
• consistent measurements?

Conserving local habitats on slapton ley

• Conservation - protecting certain species by conserving their habitat
• Coppicing - special way of cutting trees at an angle so they can grow shoots e.g hazel trees  to produce food for dormice
• Butterfly Glade - in this area, shrubs (e.g. brambles and flowering plants)  have been growing which creates a canopy - all plants absorb light 
• Management - management has cut down trees so that other plants can grow
• Ex situ conservation - conserving off the site- sending seeds to millenium seed banks
• In situ conservation - conserving on the site 
• Sanctuaries are habitats that are private from the public but used for other animals e.g. otters.

• Description of methods Description, explanation, anomaly and limitations    
• 1. Invertebrates Tally / Grab sample and count- place on tay To find out the species richness and species diversity Grab sample
• Had to wash the tray after collecting invertebrates
• Returned back to their habitats 
• Repeats - keep fairly standardised    
• 2. Ground flora Percentage cover
• Used an open quadrat than grid Quick and easy
• Find out species diversity Subjective
• different %'s from other people so take an average    
• 3. Light / temp
• (abiotic factors) Using light meter in lux
• Thermometer Measure light intensity, soil temperature. 3 readings and took an average
• People can block the actual light that the plants are getting and temperature varies during the day  

Freshwater shrimps 

• More than 6 jointed legs
• More than 8 jointed legs
• A fast swimmer and flattened body - able to escape from predators and let it move through the water easily
• They are detritivores - eat detritus and have lots of legs for movement
• Often paired up

Blackfly larva

• It has a sucker to aid it from attaching to surfaces e.g. rocks
• It has filter feeders which has the ability to make silk - track / crawl back to where it has come from
• Body has segments which aid it to loop around / movement

Stonefly Nymph

• Has 2 tails - aid to swim and help diffusion of gases / tiny holes on taiks
• Long tails more than half the body
• Little claws to help them grip
• Streamlined body- aid it to swim 

Methods of investigation DEAL = Description, Explain, Anomalies and limitations!!!!

Stratified sampling 

• Overall strategy in the riffles and pool
• D = use gridded quadrat
• E = percentage cover - estimated value and not exact value and quick
• A = counting number of algae and detritus 
• L = subjective
• Invertebrate sampling
• Grab sample
• place on a tray
• disturbance on habitat
• combining grouped data
• shuffle and kick for 20 seconds
• use a net to transfer invertebrates
• had to rinse the tray with water

Temperature

• Temperature changes during the day
• hold the probe on the water
• cannot use an electric thermometer

Mark release recapture techniques - investigate mobile species

• capture sample - appropiate technique + count
• mark in a harmless way
• release back in habitat
• 2nd sample - same populatio
• count how many marked
• total pop size = number caught (1) x number caught (2) / number marked in 2nd
• marked sample - enough time to mix back with pop 
• marking hasn't affected chance of survival +mark still visible
• changes in pop size due to death,birth+ migration = small 

Risk assessments

• trips falls + slips - suitable footwear / wellies aware of cliffs / steep ground
• bad weather - weather forecast - clothing 
• stings + bites - insect repellent / allergy/ medications 

Ethical issues

• Fieldwork affects environment - people walking / trodding - soil erosion - ensure to have smallest impact / avoid habitat disturbances
• Fieldwork affects organisms - capturing may cause stress - great care + handled well + as little as poss = released asap

•  Spearmank rank correlation - look for a relationship between 2 sets of numerical data  ... IS THERE A SIGNIFICANT CORRELATION ETC minimum of 10 paired data / compare critical value in # of pairs of data 
• Standard error and 95 % confidence intervals -  SIGNIFICANT DIFFERENCE - 5/10 more than one set of data .. IS THERE AN OVERLAP / DIFFERENCE? PROBABILITY AND CHANCE!
• Chi squared - SIGNIFICANT ASSOCIATION (preference) expected value should be >5 - compare to critical value - number of categories 

1) state which stats test to use

2) explain why it's chosen

3)state null hypothesis OPPOSITE OF HYPOTHESIS!

4) calulate stat test

5) interpret -- > than crit value or < crit value - null hyp accepted/rejected

6) explain in terms of PROBABILITY AND CHANCEEE!!!!

Soil management and fertility

• Soil erosion
• Pollution Use of pesticides and herbicides Different layers of crops
• Crows eat some insects Planting vetch as ‘green manure’    

Crop management

• Pests / diseases Antibiotics and pesticides 
• predation Chemicals used are bad for health 
• Inorganic = damaging Pest + Disease = planting different crops
• Use lime to balance PH    

Pest management

• Margins around edge of the field 
• Habitat for natural predators
• Plant variety of crops
• Mixed cropping = confuse potential pests Use of pesticides to kill pests 
• Can be poisonous to other vegetation and affect crop rains = cause eutrophication Crops can be damaged or eaten by pests 
• Affecting rain -
• cause eutrophication
• Cause organophospho poisoning Have to sell crop for less and have less profits    

Production and profits

• Supermarkets set price – can be low and changes
• Supermarkets undercutting farmers Intensive farming – produce higher yield Chemicals used can run into the lake = eutrophication Use other predators of any pests e.g. aphids and ladybirds