"poorly understood inter relationships and inter-dependencies."

Not as poorly understood as you might think. We understand very well that an ecosystem is a flow of energy, from sunlight to apex predator. Ecosystems can be stable for very long periods when they reach an equilibrium but that this stability is affected (amongst other things) by the loss of various components that reduce biodiversity, and the loss of apex predators (in the case of the moors birds like hen harriers) has significant affects on the health of an ecosystem.

I can highly recommend this book which is very readable without being dumbed down: The Wolf's Tooth: Keystone Predators, Trophic Cascades, and Biodiversity

If we could make every farmer, gamekeeper, politician and other monetised user of the land read and understand this book, the world would be a better place.