Attempts to bring about change in the condition of natural resources face significant challenges on three main fronts. Biophysically, the effects of human intervention are difficult to detect due to long time lags between intervention and response, the large spatial scales over which landscape processes operate, the large number of drivers that influence these processes and the high levels of uncertainty that will always be associated with our understanding of these processes. The major social and economic challenge is the unpredictability of markets, both traditional commodity markets and emerging environmental services markets, and their influence on resource use and the ability of land managers to invest in environmental repair. Institutional challenges include differences in land tenure (public and private), jurisdiction (national versus and state responsibilities) the planning cycles of environmental programs, and the different disciplinary language and organizational cultures of the organizations involved.

Over the last 20 years, we have seen several shifts in major environmental programs as they have attempted to respond to these challenges. Initially there was the approach of doing a bit of everything every where in recognition of the need to influence processes at a distance over large spatial scales, particularly influenced by the experience of dryland salinity. The hope was that the efforts of lots of local groups would eventually join up. We then saw devolution of planning responsibility to regions in recognition of the importance of working at appropriate scales and using local knowledge. However failure to achieve critical mass and unrealistic expectations of the time required to bring about change meant that this 'vegemite' approach has been criticized through a series of national audits and there has been a return towards national priority setting. Efficiency has now become a primary objective of governments with emphasis placed on more focused interventions that meet multiple environmental targets. Ultimately, both effectiveness of scale and efficiency in the use of public funds are necessary preconditions for change.

Another aspect of effectiveness is the need to identifying the dominant drivers of resource condition and direct our efforts at those we can influence. This paper reports on progress within the Landscape Logic partnership to do this using a combination of retrospective studies and modeling. Two examples are provided of this approach. One is using a combination of social research, field survey and modeling to tease out the major drivers of vegetation change in northern Victoria over the last 60 years. The second is using gauging station data from 34 catchments in Tasmania combined with hydrologic modeling to establish relationships between land use change and three key drivers of water quality; nitrogen, phosphorous and sediment loads in rivers.