In restoration ecology, why might it be challenging to return a damaged ecosystem to original its state/function? Why do scientists often select watersheds as an area to study energy and matter flows in'ecosystems?

in order to restore a damage ecosystem, to sow native seeds or transplanting individual plants is a first step towards the solution.

2. Because it is difficult to study biogeochemical cycles globally, it is important to research in a smaller scale in order to measure the ecosystem processes.