Ecological restoration in its literal sense, i.e. bringing a system back
to a former state, will be increasingly difficult in a globally changing world.
The recovery of degraded systems, which still remains an urgent issue, will
more and more often end up in systems that were never seen before at this
particular site. The challenges of such "forward restoration" to
"designer ecosystems" are tremendous, because it lacks any reference
state to value the success of restoration projects. The only criteria left are
"self-sustainability" and "ecosystem functions", and the
aimed assemblage of such communities implies a thorough understanding of
systems that we do not even know yet. So innovative conceptual approaches have
to be developed, based on the fields of disturbance theory, succession theory,
and assembly rules. Disturbed ecosystems should primarily be considered as
"ecosystems" instead of "disturbed", because what is left
is the ground from which the future state must be developed. Succession trajectories
can hardly be predicted, so careful monitoring of the self‑running
recovery process is needed. Most helpful will be a link to the currently
flourishing biodiversity research. Experimental approaches in this field are
dealing with the same criteria and questions, but look for general patterns in
the opposite direction compared to ecological restoration, i.e. when systems
are developing from complex to simple. In particular, biodiversity experiments
often include "artificial ecosystems", i.e. communities that were
assembled according to the experimental design and that have no natural
correlate, which may serve as models for unknown designer ecosystems.