Ecosystem 1: It is a food chain and the food chain is fragile in nature as it does not have any alternatives like the food web, here removing species from any trophic level will lead to complete destruction of the food chain.
Ecosystem 2: It is showing a food web, They are stable in nature and have alternatives and can sustain the damages like removal of any species from the food chain, here a lot of food chains are interlinked and hence there is an option or have availability of food if any species is removed.
As per the image: Ecosystem 2 is more likely to function as there is the availability of food and the removal of any species will not affect much.
As per the written question: The affected ecosystem will be Ecosystem 1 as it is fragile in nature.