Currently a plethora of scientific specialists are needed to fully analyze the impacts of human activity on public lands.  However overlap of these specialties is often insufficient to generate an understanding of the totality of impacts caused by particular human activities.  Thus, land use managers and other policy makers face major barriers to producing an integrated picture of the health of ecosystems, and decisions regarding land use and protection of habitat, waters, and species are often made with inadequate data. Yet increasing pressures of climate change, human population impacts, and new or intensifying human activities, make the successful integration of ecological knowledge an essential task for the future.     

This research applies an encompassing ecological network model to the analysis of convergent impacts of human activities on ecosystem health and function.  The "econet" ecological network framework is built upon previous analyses of species-ecosystem networks (Gremillion and Brown, 2001). Econets explicitly incorporate not only food webs, but flows of  energy, matter, and information between biotic, abiotic, and human elements of ecosystems.  The econet approach is designed to convey not only the specifics of impacts propagating throughout ecological networks, but to illustrate broader conceptual bases through  which data gaps and research needs can be derived.

Results/Conclusions

The effects of off-road recreation on public lands are parsed into an econet description. We find that impacts of off-road vehicles (ORVs) are highly divergent across ecological scales, simultaneously affecting species, habitats, abiotic flows, and ecosystem services.  Relevant impacts include erosion, air and water pollution, and negative effects on wildlife, including loss of effective habitat, habitat partitioning, and direct stress effects on wildlife populations. These effects further percolate throughout linked ecosystem networks, producing convergent detrimental impacts.  The model also extends to incorporate large-scale effects such as climate change, and its potential exacerbation due to dust, habitat alteration, and interference with hydrological flows.

In the case of off-road vehicles and public lands management, an econet approach can help identify and clarify the following to land use managers, policy makers, and the public:

• unintended but direct consequences of ORV use;
• convergent impacts of ORVs on ecosystems, habitat, and organisms, leading to changes in tipping points and species population thresholds;
• higher-order network effects, such as habitat fragmentation induced by cross-country trails significantly decreasing effective habitat, producing changes in species population types, distributions, and densities.
• sensitive locations and ecosystems where divergent impacts co-localize to produce unforeseen effects.