1. Grassland Invasion by Non-native grasses: Ecological Issues of Multiple Species at Multiple Trophic Levels and Their Associated Restoration Concerns
By: Mitch J. Greer

2. Grasslands Largest % of global land cover Perennial native grasslands
> 50% ice free terrestrial landscape
Multi-continental range
Perennial native grasslands
Very IMPORTANT
Ecologically
Economically
picgrassland.jpg

3. The Great Plains North American perennial grassland
3,200km North – South
Southern Canada – Texas
Rocky Mountains – 800km East
~1.3 million km2
en.wikipedia.org

4. The Great Plains Ecological services Human used products
Wildlife habitat
CO2 sequestration
Soil nutrient addition
Aquifer recharge
Human used products
Food
Fuel
Fiber
ethicurean.com

5. Problems in the Plains Habitat loss Climate change Habitat degradation
Row crop agriculture
Urbanization
Climate change
Alters ecosystem function
Habitat degradation
Ecological invasion
Encroaching and Invading species
creedyassociates.com
One of most endangered ecosystems in NA
mobjectivist.blogspot.com

6. Ecological Invasion Process by which: 3 Stages
New species enters a community
Native or Exotic species
Accidental or on purpose
3 Stages
Arrival
Establishment
Spread
Lockwood et al. 2007
dec.ny.gov
fortybeads.com
blog.tavelpod.comr

7. Biological Invasion ????? Research concentrations Belowground
Recruitment limitation
Aboveground traits
Belowground
Little known
Above- and belowground communities
Intrinsically linked
Regulate ecosystem-level processes
?????
Propagule recruitment and traits.

8. Arbuscular mycorrhizal fungi (AMF)
Belowground Players
Arbuscular mycorrhizal fungi (AMF)
Nematodes
Bacteria
Beneficial
Mineral solubilization
Fixing nitrogen
Access to other soil resources
Harmful
Parasitic
Pathogenic

9. AMF ~70% of all vascular plant species
Hyphae greatly increase the absorbing surface area
4-20% of plant photosynthate consumed by its AMF
Hyphae
Drawing by N. C. Johnson
Arbuscules
Photo by Joe Morton

10. AMF Importance Nutrient uptake Plant growth rate Soil nutrient pools
Drought tolerance
Resistance to root pathogens

11. C4 C3 GROWTH RESPONSE (%) SPECIES - 25 % 0 % 25 % 50 % 75 % 100 %
50 %
75 %
100 %
Andropogon gerardii
Sorghastrum nutans
Schizachyrium scoparium
Panicum virgatum
Bothriochloa bladhii
Bouteloua curtipendula
Buchloe dactyloides
Elymus cinereus
Bromus inermis
Bouteloua gracilis
Pascopyrum smithii
Agrostis stolonifera C4
Koeleria macrantha C3
Poa pratensis
Wilson and Hartnett 1998

12. AMF and the Great Plains
Van der Putten (2007)
Majority of exotic species are non-mycorrhizal
Functionally distinct from the native flora
In the Great Plains the exotic species introduced resemble the dominant C4 native species in physiological and functional traits
Need AMF to complete life cycle.
Link numerous individuals together allowing them to transport nutrients between many individuals (Wilson et al. 2006).

13. Feedback Loops
Bever, J. D. ,1997; 2003

14. Feedback Loops Negative Positive Slowed the rate of population growth
Increased or stabilized diversity
Prominent in native systems
Positive
Increased rate of species growth
Decreased species diversity
Resulting in mono-specific stands
Bever, J. D. ,1997
Bever, J. D. 1994; 1997; 2002; 2003

17. Invasion of the Great Plains
Invading native grasslands
Reduce plant biodiversity
Reduce or alter wildlife biodiversity
Hickman et al. 2006
Restoration concerns
Multiple trophic levels
Multiple spatial scales

18. Invasion of the Great Plains
Old World Bluestem (OWB)
Perennial warm – season grass
Introduced in 1917
Europe, Asia, and Russia
Erosion control
Increase forage
Central and Southern Great Plains
Millions of acres
Marginal farmlands
Road side right – of – ways
Harmoney and Hickman 2004
inspection.gc.ca

19. OWB Invasion Temporary benefit Escaped original plantings
Unpalatable after maturity
Escaped original plantings
Invading native prairies
Rapid expansion
“Creating moving fronts”
OWB better competitors
Greater biomass
Schmidt et al. 2008
Hinder native seedlings
Wilson et al. 2012
ca.uky.edu
Seedlings not survive when planted to OWB soil.
ca.uky.edu

20. Exotic: Old World Bluestem
Bothriochloa Results
Non-Sterile
+ Mycorrhizal fungi
Non-Sterile
+ Mycorrhizal fungi
Sterile
- Mycorrhizal fungi
Sterile
- Mycorrhizal fungi
Native: Big Bluestem
Andropogon gerardii
Exotic: Old World Bluestem
Bothriochloa sp.

21. Bothriochloa Results AM Root Colonization
W. KS
E. KS
W. OK
E. OK
NP = Soil Collected from Native Prairie
OWB = Soil Collected from under Old World Bluestem

22. Bothriochloa Results AM Soil Hyphal Abundance
Determined by Fatty Acid Analyses
W. KS
E. KS
W. OK
E. OK
NP = Soil Collected from Native Prairie
OWB = Soil Collected from under Old World Bluestem

23. The Take Over of South Texas
Invasive/Encroaching C4 grasses in South Texas
Pennisetum ciliare
Buffelgrass
Dichanthium annulatum
Kleberg Bluestem
Heteropogon contortus
Tanglehead
Photos from South Texas Natives

24. Study Sites Collaborative project with Texas A & M Kingsville and South Texas Natives

25. Objectives and Hypotheses
Determine if dominant native and invasive C4 grasses of S. Texas are mycorrhizal dependent.
Determine if invasive C4 grasses alter plant-soil-microbial feedbacks and limit native grass establishment and growth.
Determine if addition of native soil amendments improve establishment and growth of native grasses.

26. Methods 5 reps For each species x soil source x soil treatment
Native plant species:
Hooded windmillgrass
Chloris cucullata
Arizona Cottontop
Digitaria californica
Pink Pappusgrass
Pappophorum bicolor
Plains Bristlegrass
Setaria leucopila
Invasive/encroaching species:
Tanglehead
Heteropogon contortus
Buffelgrass
Pennisetum ciliare
Kleberg Bluestem
Dichanthium anulatum
Invasive’s not planted into other invasives as not a concern of ours.

27. Methods Soil source: Native Prairie Beneath Tanglehead (encroaching)
Beneath Buffelgrass (invasive)
Beneath Kleberg Bluestem (invasive)
Soil treatments:
Field soil (soil left nonsterile)
Field soil with native prairie soil inoculum added
Steamed (steam-pasteurized)
Steamed with native prairie soil inoculum added
Addition of native inoculum to field soil shows potential for restoration
Steamed removes AMF to allow testing of dependency
Steamed plus native soil test if biomass decreases is all microbial driven if it matches native soil
Harvested after 14 weeks:
Quantified above- and belowground biomass

28. Results
Pappophorum bicolor
Pink Pappusgrass
Pappusgrass needs AMF

29. Results AMF Dependent: Non-AMF Dependent: AMF Facultative:
Pappophorum bicolor
Pink Pappusgrass
Seteria vulpiseta
Plains Bristlegrass
Heteropogon contortus
Tanglehead
Dichanthium annulatum
Kleberg Bluestem
Non-AMF Dependent:
Chloris cucullata
Hooded Windmillgrass
Pennisetum ciliare
Buffelgrass
AMF Facultative:
Digitaria californica
Arizona Cottontop
flickriver.com

30. AMF Responsive Invasives

31. AMF Responsive Natives

32. Results Seteria vulpiseta Plains Bristlegrass
AMF obligate. Native invader shares similar evolutionary history and may have similar AMF species.
Native show reduced biomass when grown in soil from non-native dominated sites

33. Results Chloris cucullata Hooded Windmillgrass
Non-AMF dependent but still reduced. Something else going on.

34. Results Pappophorum bicolor Pink Pappusgrass
Native soil inoculum addition increased biomass but killing “bad” microbes and adding back “good” returns to native prairie level
Not so for the KB

35. Conclusions Invasive/encroaching exotic grasses
Have varied reliance on AMF
As did the natives
Exert differential effects on native grasses
Alteration of AMF community
Use of native soil amendments may hold potential
But where do we get this soil for large projects?
May be other mechanisms at work

36. Results
Pappophorum bicolor
Pink Pappusgrass

37. Chemical Warfare In Nature??

38. Objectives
Assess effects of yellow bluestem (Bothriochloa ischaemum) extractions on germination, survival, and growth of native grasses.
Big bluestem (Andropogon gerardii)
Little bluestem (Schizachyrium scoparium)
Assess effects of yellow bluestem leaf litter on survival and growth of native grasses.

39. Hypotheses
Ha1: Yellow bluestem leachate will reduce germination of native grasses, with no conspecific effects.
Ha2: Yellow bluestem leachate or litter will reduce biomass production of native grass seedlings, with no conspecific effects.
Ha3: Yellow bluestem leachate or litter will reduce the survivorship of native grass species, with no conspecific effects.
Ha4: Big bluestem leachate or litter will have no conspecific or heterospecific effects.

40. Methods Germination study: For each species (8 Reps):
50 seeds were placed into a petri dishes
5 ml added to each dish
Yellow bluestem leachate (invasive)
Big bluestem leachate (native)
Deionized water (control)
Percent germination was determined
Every 3 days for 21 days

41. Methods Survivorship and growth study:
For each species (8 replicates):
One seedling per pot
Containing 1 kg native soil
60 mL added
Initiation and every other week
Yellow bluestem leachate (invasive)
Big bluestem leachate (native)
Deionized water (control)
20 mm of leaf litter
Applied at initiation
Yellow bluestem leaf litter (invasive)
Big bluestem leaf litter (native)
No litter application (control)
Percent survival determined after 8 weeks
Biomass dried and weighed at 8 weeks

42. Results - Germination

43. Results – Aboveground (Leachate)

44. Results – Aboveground (Litter)
Belowground biomass showed similar results.

45. Results – Survivorship (Leachate)

46. Results – Survivorship (Litter)

47. Conclusions
Yellow bluestem leachate profoundly reduced the germination of native seeds, with no conspecific effects.
Yellow bluestem leachate and leaf litter significantly reduced the survivorship of native seedlings.

48. Conclusions
Big bluestem leachate had little effect on native or invasive species.
Big bluestem litter reduced biomass production of all species compared to no litter controls; greater reductions were observed with yellow bluestem litter.
Big bluestem litter did not reduce seedling survivorship of any species; yellow bluestem litter profoundly reduced native species survivorship.

49. Biochemical ID Soil treatments showed no differences
EC (soil salinity) or pH
Leachates showed only one difference
Native leachate had greater phenolic content
Native systems = negative feedbacks
tolweb.org
Bever 2003

50. Big Picture Invasion may be driven by:
Alterations of AMF community
Use of allelopathic biochemicals
May be a synergistic effect
Need for species by species management
Future research
Assess soil microbial community change
Pyro-sequencing
Biochemical identification

51. Restoration Implications
Restoration recommendations:
Use of native soil addition
Restore native soil community
Again where do we get the soil?
Negate allelopathic compounds
Determine residency time of compounds
Organic matter addition
Aid in restoring soil chemistry
Increase restoration success
Restore ecosystem function

52. Bottom-Up Effects

53. OWB and Biodiversity OWB invasion Loss of plant biodiversity
Diverse grasslands vs. monospecific stands
Loss of plant biodiversity
Loss of wildlife biodiversity
Alteration of:
Habitat structure
Habitat composition
Available resources

54. Exotics & Small Mammals
Previous work:
Cool – season exotics
Schwartz and Whitson 1987
Hayslett and Danielson 1994
OWB monocultures in Texas
Sammon and Wilkins 2005
Found lower small mammal:
Diversity
Richness
Abundance / Relative abundance

55. Justification and Objective
Small mammals
Vital to grassland ecosystems
Seed dispersers
AMF spore dispersers
Primary consumers
Objectives:
To determine if grasslands invaded by OWB contain similar small mammal communities as native grasslands.
Determine the vegetative characteristics causing any observed differences.
www2.ljworld.com
OWB will have lower species richness
Relative abundances will shift as a few species will become more abundant

56. Study Area

57. Methods: Trapping 2 treatments 4 Transects 2 years 20 traps/transect
Sherman live traps
20m spacing
>200m between transects
2 years
4 seasons/year
4 days/season
2 checks/day
Owb 40-60% invaded

58. Methods: Vegetation Visual obstruction Litter Depth
Robel pole
Litter Depth
Vegetative Composition
1m2 frame
Modified Daubenmire class method
Forb, grass, bare ground, etc
Native vs. OWB
Aerial cover
Elevated Daubenmire
5cm, 10cm, 25cm, 50cm
virtualbirder.com
June and Sept each year
hosho.ees.hokudai.ac.jp

59. Vegetative Measurements
Native
B. ischaemum
+Native Species
+ Litter Depth
+ Native Species 5cm
+ B. ischaemum
+ Native Species 10cm
+ B. ischaemum 5cm
+ B. ischaemum 10cm
+ B. ischaemum 25cm 59

60. Species Actual Captures
Results
5120 total trap days
24 hrs in 1 day
Species Actual Captures
Species
Native
OWB
Deer Mouse
101 36
Cotton Rat 74
237
Elliot's Short-tailed Shrew 3 10
Fulvous Harvest Mouse 4 1
Prairie Vole 7
Hispid Pocket Mouse
Eastern Harvest Mouse
White-footed Mouse 2
TOTAL
193
294

61. Species Richness

62. Relative Abundance
All indicies show similar trends.

63. Habitat Models 63

64. Habitat Models 64

65. Model Summary Cotton rat Deer mice Increased aerial predator avoidance
Major source of mortality
Deer mice
Increased foraging efficiency
Lower seed recovery in thick litter/vegetation
Smaller body size
vet.osu.com
Realanimallife.com 65

66. Conclusions Native grasslands OWB invaded grasslands
Higher species richness
Higher relative abundances of deer mice
OWB invaded grasslands
Higher relative abundances of cotton rats
Vegetative structure showed few differences
May be due to 40-60% invasion vs. monoculture

67. Conclusions OWB invasion leads to: Promote early eradication of OWB
Fewer species
Greater abundances of these species
Promote early eradication of OWB
60% invasion saw only minor shifts
Lag in small mammal community shift
Increased fire frequency may maintain native habitat structure
Greater ecological concerns

68. Summing it Up Invasive species = BIG PROBLEM
Economic Concerns
$35 billion cost to control or in lost product
This does not cover cost of restoration
Restoration of invaded lands is complex
Focus has been on above ground BUT…
Current projects show belowground can be just as or even more important

69. Big Picture Invasion may be driven by: Tangled web!
Alterations of AMF community
Use of allelopathic biochemicals
May be a synergistic effect
May be more complex
Tangled web!
Early control and restoration can limit impacts
Need for more research

70. Acknowledgments
Funding: OSU- Natural Resource Ecology and Management Texas A & M Kingsville: Tim Fulbright Caesar Kleberg Wildlife Research Institute South Texas Natives David Davidson Konza Prairie Biological Station NSF -LTER Fort Hays State University K-State Hays Ag Experiment Station: Keith Harmoney USDA Range Research Program Project Support: Stuart Wilson (OSU – PSS) Chris Stansberry (OSU – SRR) Dr. David Lalman – OSU – Animal Science TX A & M Kingsville Graduate Student: Eric Grahmann OSU Graduate Students: Shubha Shrestha, Morgan Noland, Eric Duell, Stephanie Grischkowsky, and many others Numerous undergraduate research assistants Numerous Volunteers (OSU – TWS)