1. Growth of native and exotic plants during the 2000 Low Steady Summer Flows Or: Be careful what you ask for… Marianne E. Porter Michael J.C. Kearsley Dept. of Biol. Sciences Northern AZ. University Flagstaff, AZ

2. Possible LSSF Experiment Outcomes: * Bla Bla Bla native fish recruitment * Bla Bla Bla seasonal hydrology * Bla Bla Bla near-shore current velocity * Bla Bla Bla increased water temperature *Recruitment of clonal herbaceous species (Equisetum, Juncus, Phragmites) *Recruitment of exotic species (Tamarix, Alhagi) in near shore areas

3. Importance of plant colonization Vegetated shoreline: vegetation (primarily Tamarix chinensis) in or directly over the water, either rooted or inundated. May have intermittent stretches of other shoreline types. Densities of humpback chub are nearly double those found in other shoreline types (Converse et al 1998).

4. 31,500 19,000 8,000 River Stage Pre-Low Flows Conditions

6. Research Questions: Do plants colonize newly available habitat? (8 kcfs – 19 kcfs) Nature of these colonists?Native / Exotics? Clonal / Seed-dispersed? Impacts of a short-duration high flow? Effects of low flows on extant vegetation at the 31 kcfs stage elevation?

7. Sampling Transect Design 31 kcfs 19 kcfs 8 kcfs = 0.25 m 2 Plot 5 – 18 Plots / Transects 6 – 14 Transects / Site Sampled Monthly June – Sept 2000 April 2001

8. Study Period Hydrograph Sampling

9. Nearshore Vegetation Study Sites

10. Data Analysis Repeated Measures AOV on Plant Densities Time, Site, Time*Site Data Transformations All Species Individual Species Tamarisk, Equisetum

11. Plant colonization: June

12. Plant colonization: August

13. Plants Below 19 kcfs

14. High elevation Equisetum

15. All Equisetum

16. Low and High Elevation Tamarisk

17. Winter Mortality is Low

18. River’s Edge Mortality

19. Conclusions Plants colonized areas below 19,000 cfs creating subadult fish habitat Colonists primarily Tamarisk Clonal herbaceous species were slower Fall high flows reduced plant densities Winter mortality was low for all species Recreation impacts of near-shore plants