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Questions How are plant species richness and diversity related to spatial autocorrelation under grazed and ungrazed conditions in grassland communities? Is spatial autocorrelation dissimilar within different plant communities? Location The grasslands of southeast North Dakota, USA. Methods The study was conducted during the summer of 2009 in six grasslands under different management (grazed vs ungrazed with fire) along a moisture gradient. Spatial autocorrelation at each site was measured along 50-m transects among three different landscape positions representing different moisture levels. Dissimogram multivariate analysis was used to measure the nugget, dissimilarity and patch diameter. Additionally, richness and Shannon diversity indices and nonmetric multidimensional scaling analysis were compared to the dissimogram results. Results Mean patch diameter was significantly higher in grazed mid-slope sites than in ungrazed sites. Spatial autocorrelation was not different between the landscape positions (higher, dry areas were not different from lower, mesic areas). However, plant species richness, diversity and community composition were found to be different between landscape positions and management, with key differences in the presence of certain invasive species. Conclusions Disturbance and moisture level were reflected differently in the spatial autocorrelation analysis compared to the richness, diversity and ordination analyses. This indicates that disturbance and management impacted spatial autocorrelation separate from plant community composition and species diversity. This also highlights changes in the plant community caused by different management actions and the spread of invasive species. [ABSTRACT FROM AUTHOR]

Abstract: Understanding how physical parameters within and adjacent to Prairie Pothole Region wetlands affect the surrounding biological communities is important for sound management decisions for agricultural and rangeland settings. We evaluated the wetland, adjacent non-wetland, and landscape physical parameters role in determining low prairie (sub-irrigated) species composition. We first developed hypothetical models using the physical variables collected from 193 wetlands in relation to the existing plant communities. The models were then evaluated using structural equation modeling and a final (alternative) model was developed from these results. The models developed indicated the importance of the low prairie community in proper ecological functioning of associated wetlands. A number of physical parameters measured can be used as indicators of declining plant community condition, one example being the potential of the low prairie plant community to be invaded by exotic species such as Bromus inermis Leyss. [Copyright &y& Elsevier]

Abstract: The Index of Plant Community Integrity (IPCI) was developed to assess wetland plant communities in the Prairie Pothole Region. The IPCI evaluates the condition of wetland plant communities based on disturbance level and multiple community attributes. However, the index was developed for seasonal wetlands from limited spatial and temporal data. We tested the index for seasonal wetlands and developed an index for temporary and semi-permanent wetlands by evaluating vegetative composition of wetlands throughout the Northern Glaciated Plains and Northwestern Glaciated Plains Ecoregions of South Dakota, North Dakota, and Montana. In 2003 and 2004, we selected wetlands based on classification and type of disturbance, ranging from little disturbance (native rangeland) to heavily disturbed (cropland). We analyzed the data using the IPCI vegetation metrics developed for seasonal wetlands, and further analyzed using nonmetric multidimensional scaling and cluster analyses. All vegetation metrics tested were significant in indicating disturbance level. Based on data analysis, five biologically significant groups related to intensity of disturbance (Very good, Good, Fair, Poor, and Very poor) were determined for seasonal wetlands, and three condition classes (Good, Fair, and Poor) for temporary and semi-permanent wetlands. Score ranges were assigned to the metrics according to the determined classes. Using the IPCI method, wetlands throughout the Northern and Northwestern Glaciated Plains of South Dakota, North Dakota, and Montana may be placed into disturbance classes. This data can then be used for ecological purposes and mitigation needs such as monitoring trends on reclaimed or restored wetlands, regional inventories, and for evaluation of ecological functions. [Copyright &y& Elsevier]

We developed an Index of Plant Community Integrity (IPCI) for quantitatively assessing the quality of seasonal wetland plant communities. In 1998 and 1999, we sampled the plant communities of 46 seasonal wetlands in the Prairie Pothole Region (PPR) of central North Dakota, USA. We selected wetlands that represented a range of disturbance from well-managed native rangeland to heavily disturbed cropland. We delineated plant data into metrics of the data set (e.g. species richness, percentage of introduced and annual plants) and analyzed these metrics using principal components (PCs) and cluster analyses. Through analyses, five quality classes (Very good, Good, Fair, Poor, and Very poor) were determined. We then assigned ranges and scores for each metric based on the statistical analyses. By using this classification system, the plant communities of additional seasonal wetlands in the PPR can now be assessed and placed in quality classes for mitigation or ecological purposes, such as tracking the improvement of restored or reclaimed wetlands, wildlife habitat evaluation, hydrogeomorphic (HGM) assessment, and evaluation of other ecological functions. [Copyright &y& Elsevier]

A statewide condition assessment of North Dakota wetlands in the summer of 2011 was conducted as part of the U.S. Environmental Protection Agency's National Wetland Condition Assessment (NWCA). Two other wetland condition assessments, the Index of Plant Community Integrity (IPCI) and North Dakota Rapid Assessment Method (NDRAM), were also completed at each wetland. Previous studies have identified how the distinct signatures of stable isotopes can be used to determine different land uses, anthropogenic impacts, nutrient cycling, and biological processes. To evaluate if these relationships existed in northern prairie wetlands, the data collected from the wetland assessments were compared with the natural abundance of soil nitrogen (δ 15 N) isotopes. Wetland soil δ 15 N was significantly higher (isotopically heavier) in wetlands surrounded by cropland compared to those surrounded by idle or grazed/hayed grasslands, possibly reflecting anthropogenic impacts and multiple nitrogen sources. Soil δ 15 N was significantly correlated with floristic quality, IPCI scores, NDRAM scores, and average buffer width, indicating that soil δ 15 N values may be representative of wetland condition. Soil δ 15 N exhibited significant differences among wetland types, although limited sample sizes of certain wetland types may have affected this result. Additional studies on the natural abundance of wetland soil isotopes need to be performed in northern prairie wetlands. This study is the first step in exploring the potential applications of wetland soil nitrogen isotopes regarding wetland assessment and surrounding land use and provides important insight for future studies. [ABSTRACT FROM AUTHOR]