It has been known for some time that land use change has major impacts on catchment behaviour and hydrology, and on the water quality in rivers and estuaries. Natural landscapes, dominated as they are by largely undisturbed ecosystems responding to biophysical constraints, are characterised by high biodiversity, high nutrient and water use efficiencies and what I have called MaxEnt and MaxET solutions arising from SGC or HOT designs. These are the robust ‘neutral domain’ solutions arrived at by long periods of selection through trial and error. In forested systems it may take as long as a few hundred years for the ecosystem to fully develop in terms of the maturity of individual trees and the overall biodiversity; even then there is constant change as patches form and close through disturbance, death and reinvasion. After major disturbance (fire, flood, windthrow, logging, etc.) ecosystems go through a rebuilding sequence of invasion and development. Overall productivity is high in early successional stages but at maturity there is a balance between production and decomposition. This aspect of ecology has been well studied since the early days of ecological investigation. Given time for the development of ecosystems with high biodiversity and maturity (efficient energy and nutrient cycling) then it is clear that production through photosynthesis becomes largely balanced by decomposition and respiration and that internal nutrient recycling is very efficient so that nutrient exports are small.