Citation:

Jones, K B., A C. Neale, T G. Wade, J D. Wickham, M S. Nash, C M. Edmonds, K. H. Riitters, E R. Smith, AND R. D. Van Remortel. MULTISCALE RELATIONSHIPS OF LANDSCAPE CHARACTERISTICS AND NITROGEN CONCENTRATIONS IN STREAMS . Jianguo, Wu, K. Bruce Jones, Li Harbin, Orie L. LOoucks (ed.), Scaling and Uncertainty Analysis in Ecology Methods and Application. Columbian University Press, Cambridge, NY, , 205-224, (2006).

Impact/Purpose:

The primary objectives of this research are to:

Develop methodologies so that landscape indicator values generated from different sensors on different dates (but in the same areas) are comparable; differences in metric values result from landscape changes and not differences in the sensors;

Quantify relationships between landscape metrics generated from wall-to-wall spatial data and (1) specific parameters related to water resource conditions in different environmental settings across the US, including but not limited to nutrients, sediment, and benthic communities, and (2) multi-species habitat suitability;

Develop and validate multivariate models based on quantification studies;

Develop GIS/model assessment protocols and tools to characterize risk of nutrient and sediment TMDL exceedence;

Complete an initial draft (potentially web based) of a national landscape condition assessment.

This research directly supports long-term goals established in ORDs multiyear plans related to GPRA Goal 2 (Water) and GPRA Goal 4 (Healthy Communities and Ecosystems), although funding for this task comes from Goal 4. Relative to the GRPA Goal 2 multiyear plan, this research is intended to "provide tools to assess and diagnose impairment in aquatic systems and the sources of associated stressors." Relative to the Goal 4 Multiyear Plan this research is intended to (1) provide states and tribes with an ability to assess the condition of waterbodies in a scientifically defensible and representative way, while allowing for aggregation and assessment of trends at multiple scales, (2) assist Federal, State and Local managers in diagnosing the probable cause and forecasting future conditions in a scientifically defensible manner to protect and restore ecosystems, and (3) provide Federal, State and Local managers with a scientifically defensible way to assess current and future ecological conditions, and probable causes of impairments, and a way to evaluate alternative future management scenarios.

Description:

There have been numerous papers reporting relationships between watershed andlandscape characteristics and chemnical, physical,m and biological attributes of streams (see summary in Lee et al. 2001). Some of these studies have shown strong linkages between stream and near-site landscape conditions (Lammert et al. 1999, Stauffer et al, 2000, Talmage et al. 2002), while others show stronger linkages between stream and watershed scale,landscape conditions (Roth et al. 1996, Allan et al, 1997, Herligy et al. 1998, Davies et al. 2000, Jones et al. 2001a). Moreover, there are differences in the importance of environmental variables in explaining variation in stream condition among the various studies ( for example, see Roth et al. 1996 and Lee et al. 2001, for a comparison).

Differences in results are not surprising given the wide range of scales and biophysical settings in which these studies were conducted, and the potential for variation in environmental conditions (e.g., precipitation and flow) among the years in which these studies were conducted. Scaling is considered to be one of the top challenges facing environmental managers and ecologists alike (Wu 1999, Wu and Hobbs 2002). Stream chemistry , including nitrogen concentration, seems to be controlled by overall watershed conditions (Carpenter et al. 1998, Herlihy et al. 1998, Jones et al. 2001), although point sources and atmospheric nitrogen deposition also can be a significant sources of nitrogen in streams (Behrendt 1996 and Smith et al. 1997, respectively). Studies of the importance of land cover and land use in riparian zones is well documented (Lowrance et al. 1984, Peterjohn and Correll1984), but most have been limited in geographic scope and biophysical variability .Moreover, little is known on how effective forested riparian buffers are in filtering nitrogen in different biophysical settings across broad regions.

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