Reducing threats to the health and integrity of the restored system: What does this mean and how do we do it?

In order to reduce the threats to the health and integrity of a restored system we first need to define both the health and integrity of that ecosystem. According to the accepted SER definition of restoration, a restored ecosystem should have the appropriate biotic and abiotic resources that will self-sustain itself structurally and functionally, without further human intervention. It should also have intrinsic resilience to the expected range of stress and disturbance. It is therefore self evident that defining ecosystem health and integrity requires appropriate baseline knowledge of both reference conditions (ie. the pristine system), the pre-restoration state and the stressors that were present. In reality the restored system will lie somewhere between the extremes of reference and pre-restoration state. Once the health and integrity have been defined we then need to identify the threats that exist and more importantly assess the level of threat (ie. intensity, frequency, duration and scale). If not identified the threats could cause the ecosystem to degrade towards the pre-restoration state or there may be new threats (eg. invasive species; environmental temperature rise)  that could cause the system to move towards a different state. Reducing threats will require a fundamental shift in attitude to resourcing restoration projects (both pre and post restoration) and a specific knowledge-base particularly over different scales. I will illustrate the concept of ‘how to do it’ with examples from aquatic ecosystems.