Thursday, August 5, 2010

PS 84-157: Long-term ecological monitoring to detect trends in northern Colorado Plateau uplands

Dana L. Witwicki and Dustin W. Perkins. National Park Service

Background/Question/Methods

The Northern Colorado Plateau Network (NCPN) of the National Park Service monitors upland vegetation and soils in 11 parks on the Colorado Plateau.  Uplands represent the vast majority of land area in these parks and include grasslands, shrublands, woodlands, and forests. Upland ecosystems of the Colorado Plateau are characterized by low resistance and resilience, and global climate change is expected to alter levels and seasonality of dominant precipitation events, with unknown implications for plateau systems.  The goal of the NCPN integrated upland monitoring effort is to provide park managers with status and trend information for vegetation and soil attributes. This information increases fundamental understanding of upland systems and provides managers with early warning of undesirable change. These goals are accomplished partly through sampling design and data analysis. Evaluation of upland monitoring data relative to other data, such as ecosystem thresholds, landscape-scale data, climate records, etc., facilitates identification of drivers and helps to distinguish “natural” from anthropogenic change. Monitoring was initiated in 2006 based on random spatially-balanced survey designs for each park. Annual reports of status are summarized for each park, and NCPN will begin to look for trends after 5 full years of data collection.

Results/Conclusions

Preliminary analyses of grassland ecosystems at Capitol Reef National Park indicate that areas currently grazed by cattle have more invasive annuals, lower cover of perennial grass and biological soil crust, and larger canopy gaps than areas that are no longer grazed.

Successful long-term ecological monitoring of uplands involves carefully considered sampling designs for the appropriate areas of inference. Assessing variability of ecosystems helps us to understand adequate sample sizes and sampling designs to detect trends and to divide the affordable effort between high priority ecosystems.  Input from park managers is essential to develop sampling designs that detect the effects of climate change and to make monitoring relevant for resource management decisions.