Presentation on theme: "Melinda Lamb. Watersheds have significant impacts Lake Conditions Bed rock leaching Top soil depth (Brown et al. 2008) Vegetation Nutrient uptake/ soil."— Presentation transcript:
Watersheds have significant impacts Lake Conditions Bed rock leaching Top soil depth (Brown et al. 2008) Vegetation Nutrient uptake/ soil chemistry Water consumption/routing
Lake Productivity Properties linked to Watersheds Chlorophyll –A Nutrients - N and P Lake transparency Nutrient cycling leads growth and productivity of primary producers Regulates and influences the oxygen levels. Oxygen is necessary for respiration of aquatic animals and for excluding P from leaching out of the soil.
Reed canarygrass Creates dense monospecific stands Limits light availability, water, and nutrients Known to reduce habitat for ground nesting birds due to dense composition Reduces tree seed recruitment by monopolizing light and creating a dense canopy Loves cool, wet places but can and will tolerate a wide range of habitats including hot and dry.
Reed canarygrass alters lake functions Nutrient cycling Water consumption Increased sedimentation yeilding water diversion Disolved Organic Carbon (DOC) levels
High Rate of Decompostition and N and P Leaching (Kao et al. 2003) RankSpecies N Retention (g N m 2 2) Species P Retention (g P m 2 2) 1S. americanum9.7J. effusus1.3 2J. effusus9.3S. americanum0.9 3S. cyperinus7.1C. canadensis0.49 4C. canadensis4.7S. cyperinus0.46 5P. arundinacea3.3P. arundinacea0.2 Table 2. Net shoot retention of N and P estimated for the five species in rank order. Recreated from Kao 2003
Leaching results from Kao et al. 2003 Figure 5. Percentages of a) nitrogen and b) phosphorus retained in shoot litter after 60, 120, and 150 days of decomposition. Means for Scirpus (triangle), Juncus (diamond), Calamagrostis (square), Sparganium (X) and Phalaris (circle) are shown with standard errors for 5 replicates. There were no significant results for 60 and 120 days.
Changes to DOC Vegetation compositions yeild significantly different BDOC concentrations in runoff (Fellman 2006) Watershed composition of forested wetland linked to DOC levels (Xenopoulos 2003) Lake shoreline composed of wetland, is linked to DOC levels (Xenopoulos 2003)
Conclusion Reed canarygrass can lead to a high nutrient runoff events, lower DOC levels and lower water circulation. Reed canarygrass can contribute the eutrophication of lakes although it has been traditionally thought to be a plant used to prevent eutrophication. The effects will be more obvious in shallower, lower volume lakes with more complexity in the shoreline development.
Brown, P. D, Wurtsbaugh, W. A., Nydick, K. R. 2008. Lakes and Forests as Determinants of Downstream Nutrient Concentrations in Small Mountain Watersheds. Arctic, Antarctic, and Alpine Research. 40: 462- 469. Lavergne, S., Molofsky, J. 2004. Reed Canary Grass (Phalaris arundinacea) as a Biological Model in the Study of Plant Invasions. Critical Reviews in Plant Sciences. 23: 415-429. Lefor, M. W. 1987. Phalaris arundinacea L. (reed canary grass, Gramineae) as an hydrophyte in Essex, Connecticut, USA. Environmental Management. 11: 771-773 Martina, J., von Ende, C.. Correlation of soil nutrient characteristics and reed canarygrass (Phalaris arundinacea: Poaceae) abundance in Northern Illinouis (USA). Am. Midl. Nat. 160:430-437. Kao, J., Titus, J., Zhu, W.. 2003. Differential Nitrogen and Phosphorus Retention by five wetland plant species. Wetlands. 23: 979-987. Xenopoulos, M., Lodge, D., Frentress, J., Kreps, T., Bridgham, S., Grossman, E., Jackson, C. 2003. Regional comparisons of watershed determinants of dissolved organic carbon in temperate lakes from the Upper Great Lakes region and selected regions globally. Limnology and Oceanography. 48: 2321-23334.
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