Community ecology, biodiversity and conservation

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Job of ecologists is to reduce complexity so we can understand and decribe interactions more easily and notice when changes occur.

The interactions between all the species in a community= FOOD WEB

This can be made up of many food chains.

Food webs are highly complex systems e.g. Ythan esturay, Scotland- despite being in the North of Scotlnd- 92 species, 440 feeding links, 5500 food chains. 

On the other hand- coral reef just fish: 500-1000 species

Difficult to comprehend and understand.

How do we determine the linkages?

  • Observations (visual and photographic) -easier in some habitats e.g African Savannah, may not be so easy in oceanic ecosystems or with nocturnal species. -Getting easier with camera traps and remote cameras- triggered by movement; slow motion cameras etc.
  • Stomach content analysis - downside is the animal is killed- useful to use on already deceased individuals e.g. to investigate plastic in stomaches. Some individuals vomit up what they have just eaten when caught. Feeding tube- reach down throat and bring up stomach contents.
  • **** analysis- different species have different ear bones- otoliths- can work out which species is eaten. 
  • Stable isotope analysis (particularly N) the closer to the bottom of the food chain- the higher the quantity of some N isotopes you will find. 

Classify organisms into different levels. 

e.g. Biomass

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