Revegetation of Weed-Infested Plant Communities

1. Revegetation of Weed-Infested Plant Communities Jane Mangold Extension Invasive Plant Specialist

2. Begin with the end in mind. . . • Kill the weed—Yes, but not the whole story • Healthy plant community that meets management objectives

3. Vicious (and Frustrating) Cycle

4. Traditional Weed Management Herbicides Biocontrol Hand-pulling Revegetation WEED Grazing Fertilization Prevention Fire Tilling/disking Mowing Irrigation

5. Future Management Biocontrol Herbicides Hand-pulling Revegetation Grazing Life cycle of weed Plant Community Desired Vegetation Prevention Fertilization Fire Tilling/disking Irrigation Mowing

6. What can we do to cause this? What caused this?

7. Necessary Components for Plant Community Change Plant Community Undesired State Site Availability Species Availability Species Performance Plant Community Desired state

8. Managing Plant Communities

9. Step 3 Assess Soil and Site Properties Are they acceptable? yes Step 2 Determine Necessity of RevegetationIf unsure, contact local Extension, weed coordinator, NRCS, or Conservation District office and schedule a site visit. Is revegetation necessary? Step 1 Make a Goal Statement Describe desired condition. Can soil be amended or are species available that are adapted to the soil? no yes yes no no Step 4 Site Preparation Consider seedbed preparationand/or soil amendments. Stop Revegetation is not recommended. Stop Allow natural recovery. Monitor frequently to identify and rectify problems. Step 7 Determine Seeding or Planting Method Is site accessible to equipment? 12 step program for reducing chemical control dependency Step 6 Design Seed Mix Create seed mix based on goals and site characteristics. Is the site a natural area? no Are invasive weeds a problem at the site? Use native species to provide ecological stability and maintain plant community integrity. Step 5 Reduce Weed InterferenceMethods vary depending on many factors. yes yes yes no no Always use native species when their abilities meet your needs. Non-natives are sometimes the only choice when needs are based on considerations like forage production and competitiveness with invasive weeds. Step 12 Long-Term ManagementCarefully manage to favor seeded species. Step 11 Monitor Monitor establishment to identify and rectify problems in time to allow successful revegetation. Step 10 Assist Establishment May include actions that precede or immediately follow seeding/planting. • Hydroseed sloped sites • Roughen soil surface before and after broadcast seeding and apply hydromulch • Hay mulch seed • Plant rhizome sprigs in high- salinity sites. • Broadcast seed a non-prepared seedbed at double to triple seeding rate • Hand-plug wetland/riparian plants. Step 8 Calculate Seeding Rate Rates vary depending on many factors. Step 9 Determine Best Time to Seed Indicated by selected species, method of planting, and soil texture.

10. Step 1—Make a goal statement difficult • Revegetation • Returning vegetation to a site; little emphasis on amending ecological function • Rehabilitation • Returning a site to a functioning state, but not necessarily its original state • Native species not required • Restoration • Returning a site to its original, functional state • Native species are required very difficult

11. “Assisted Succession” • Restoration of weed-infested rangeland may require multiple steps Cheatgrass/ annual forbs Introduced, competitive grass Native vegetation

12. Example Goal Statements • Short-term goals • At the end of YR1, reduce weed cover by 25% and increase desirable grass and forb cover by 25%. • Mid-term goals • At the end of YR5, reduce weed cover to <20% and increase desirable grass and forb cover to >50%. Hand-pulling and or spot treatment is used to control weeds. • Long-term goals • At the end of YR10, weeds occur only infrequently (controlled by hand-pulling) and site is dominated by desirable grasses and forbs.

13. Step 2—Determine if revegetation is necessary • Sites with >20-30% canopy cover of desired vegetation can usually recover naturally if performance of weeds is hindered Canopy cover = area of ground covered by plant foliage

14. Step 3—Assess soil and site properties • Assess soil properties to determine if they are acceptable or can be feasibly amended

15. Soil Properties

16. Site Properties • Precipitation • Temperature • Elevation • Aspect • Soil moisture • sub-irrigated • dry, upland

17. Step 4—Prepare site • Seedbed • Firm enough to allow good seed-soil contact • Loose enough to allow seed to sprout and penetrate soil • Preparation depends on seeding method • Usually not necessary for drill seeding • Highly recommended for broadcast seeding It’s all about balance!

18. Site Preparation • Compacted soil (high bulk density) • Limits air exchange, water infiltration, and number of safe sites • Scarify, till, disk, or plow

19. Site Preparation • Chiseling or harrowing • Plowing • Disking • Dragging small chains • Limit the amount and intensity of disturbance! • Weed like disturbance! Do so shallowly to avoid nitrogen release disked strips—notice brown, cured cheatgrass

20. Site Preparation • Herbicide application • Burning • Imprinter Create safe sites

21. Site Preparation - Soil Amendments • Fertilizer is typically not necessary • Organic matter • May also decrease nitrogen availability • Mycorrhizal innoculants

22. Step 5—Reduce Weed Interference • Herbicides • Mowing • Grazing • Biocontrol • Cover crop • Late season herbicide application combined with fall dormant seeding (single entry revegetation) Do for a couple years prior to seeding to weaken weeds

23. Herbicide Selectivity • Non-selective • Kills/stresses any plant • E.g. Roundup, Journey • Selective • Affects some plants, but not all • Tolerance varies from species to species • E.g. 2,4-D, Tordon, Transline, Milestone, most range and wild land herbicides

24. Herbicide Selectivity • Roundup • Tordon • 2,4-D • Plateau • Transline • Milestone • NONE • MODERATE • MODERATE • MODERATE to HIGH • HIGH • MODERATE

25. Single Entry Revegetation

26. Single Entry Revegetation • Tested on Russian knapweed in eastern OR Control plot Single entry revegetation plot

27. Step 6—Design seed mix • Avoid pre-made mixes from unknown or far away sources!

28. Step 6—Design seed mix • Customize to meet goals • Forage production • Minimize erosion • Minimize weed invasion and re-establishment • Restore a healthy and diverse plant community • Customize to site conditions • Soil properties (e.g. texture, salinity) • Precipitation, temperature, elevation, aspect, soil moisture

29. Seed Mixes • Functionally diverse • Grasses • Forbs • Shrubs • Species-rich • Productive • Weed-free, quality seed • Increased resource capture and reduced risk of re-invasion

30. Step 7—Determine planting methods • Drill • Most often preferred • Broadcast • Steep, rocky, or remote sites • Hydroseed • Slopes 3:1 or steeper • Hay-mulch • Spread hay containing seeds over prepared seedbed • “Island” seeding

31. Drill Seeding • Seed depth and rate are closely controlled • Good seed-to-soil contact • Shortcomings • Rows look unnatural • Long, narrow seeds may become lodged in seeder • Species require placement at different depths • Seeds of different sizes separate in box—add carrier such as cracked corn or rice hulls • Drill furrows can enhance erosion—seed along contour

32. Island Seeding

33. Distance to Recruit Patches Reever Morghan et al. 2005. Ecological Restoration 23(3):214-215

34. Step 8—Calculate seeding rate • Typically 20-50 seeds/ft2 • Determine rate based on pure live seed (PLS) • Determine rate based on seeding method and situation • Increase rate 2-3x for broadcast seeding • Increase 2-3x for weed-infested areas • Adjust individual species rates according to its desirable proportion of the mix

35. Pure Live Seed (PLS) • Measure used by seed industry to describe the percentage of a quantity of seed that will germinate • PLS = %purity X %viability • Standardizes quality so puchaser can compare quality and value of different seed lots 100

36. Read the label!

37. Do the math! • Lower $/lb., but lower purity and viability = buying more seed to achieve target seeding rate • Higher $/lb., but higher purity and viability = buying less seed to achieve target seeding rate

38. Step 9—Determine best time to seed • Cool season species • Fall-dormant during late fall • Riparian plugs • Warm temperatures, long days,adequate water • Late summer planting only if supplemental water is available

39. Step 10—Assist establishment • Seedling establishment is most vulnerable stage of revegetation program • Implement management to protect sensitive seedlings • Supplemental irrigation • Defer grazing • Mulch

40. Step 11—Monitor progress • Identify and fix problems in time to allow for success • Level of monitoring increases with severity of site conditions

41. Step 12—Long-Term Management • Tailor management to maintain developed plant community • May include • Multi-species grazing • Allowing low-intensity disturbance, e.g. fire, proper grazing • Controlling re-establishing weeds

42. Plant Community Undesired State Site Availability Species Availability Species Performance Plant Community Desired state

43. Information adapted from: Revegetation Guidelines for Western Montana: Considering Invasive Weeds by K. Goodwin, R. Sheley, and J. Marks Montana State University Extension Bulletin 170 http://msuextension.org/publications/AgandNaturalResources/EB0170.pdf $3/copy from Extension Publications (994-3273)

44. Questions? Thank you! • For more information: • EB0019 “Dryland Pastures in Montana and Wyoming” http://msuextension.org/publications/AgandNatural Resources/EB0019.pdf • Jane Mangold, Extension Invasive Plant Specialist • 994-5513; jane.mangold@montana.edu

45. Plant Communities Always Change (“Succession”) • Process whereby one plant community changes into another. It involves the immigration and extinction of species, coupled with changes in the relative abundance of different plants. -Plant Ecology by M.J. Crawley

46. Initial Plant Community Site Availability Species availability Species Performance Final Plant Community Herbicide Biological control Biological control Grazing Repeated Spring Grazing Revegetation Tilling Grazing Hand pulling Hand pulling Fire Fertilization Mowing/cutting Herbicide

47. Tilling improved establishment of seeded species in Russian knapweed infestation Mangold et al. 2007

48. Sheley, R. 2007. Weed Science 55:365-370

49. Competitive Effects of Seeded Grasses Whitson and Koch 1998