the relationship of bulbous bluegrass (poa bulbosa) and big sagebrush (artemisia tridentata) in utah
DESCRIPTION
Presented at the Utah Section Society for Range Management Meetings in Cedar City November 2013TRANSCRIPT
Sheri Hagwood @ USDA-NRCS PLANTS Database
The Relationship Of Bulbous Bluegrass (Poa bulbosa) And
Big Sagebrush (Artemisia tridentata) In Utah
Overview of Presentation
• Range Trend Project• What is Bulbous bluegrass?• What is known about it?• History of its introduction in the US• Its distribution in the US and Utah?• The relationship of bulbous bluegrass, big
sagebrush, and cheatgrass• Examples of bulbous bluegrass increase in
dominance on range trend sites
History of Range Trend Monitoring
• 1958 - Range inventory project established• 1981 - BLM and USFS partner with UDWR in range
trend program to develop Range Trend Study Guidelines
• 1982 - Permanent trend studies established using trend study guidelines with continued monitoring on 5 year rotation– Additional study sites have been established since 1982– Range trend sites are mainly found on crucial deer winter
range
Range Trend Monitoring Data Range trend study sites are monitored on a 5 year rotation
Each study site is intensively monitored
Methods• Nested frequency
‒ Measurement for abundance grass and forb species‒ 100 quadrats (1/4 m2)‒ Numerical value between 1-500 (prior to 1992 values 1-400)
• Modified Daubenmire Cover-class method‒ Measurement for % cover for grass, forb, and browse species‒ 100 quadrats (1/4 m2)‒ Ocular cover estimate
Bulbous Bluegrass (Poa bulbosa)
INFLORESCENCE •Bulblet formation or Vivipary asexual reproduction (shown in picture).•Normal seed production is rare in North America.•Each bulblet can produce a new plant.
© Gerald D. Carr
© Gerald D. Carr
© Gerald D. Carr
ROOT STRUCTURE •Consist of a bulbous base (shown in picture).•Bulbils are formed from the bulbous base reproducing asexually.•Shallow root structure.•Bulbs can withstand very dry periods time and dry to below 10% moisture content.•Sod forming
Life History
What Is known • Growth characteristics• Reproduction• Dormancy• Palatability• Life cycle• Production– Limited forage value
• Control?
What is not known• The effect it has on
ecosystems• Not much is known
about how it affects other plants
• Effect on fire regime• Effect on soil moisture• *Does it affect
sagebrush communities
Weedy Characteristics
• Similar to Cheatgrass • Short-lived perennial species• Growth occurs in early spring and re-sprouts in fall• Exists dormancy before most plants• Impacts soil moisture? • Can remain dormant for long periods of time and re-
sprout from bulbs in the soil• Sod forming ??? Does it affect other plants due to these traits ???
HISTORY OF POBU IN U.S.• Unknown - Introduction likely from
contaminated alfalfa and clover seed from Eurasia
• 1901 - First collected in Oregon.• 1906 - USDA acquired bulblets from Russia for
experimental seedings. • 1906-1930’s - USDA experimental seedings.
– Intended for use as a commercial turf grass.
• Early to mid-1900’s - used for soil erosion and to improve depleted rangelands in the intermountain west.
• Early to mid-1900’s - experimentally seeded in parts of Utah, Nevada, Idaho, and Wyoming to identify traits favorable for palatability and forage production.
• 1956 - USDA developed a POBU cultivar for seed growers but was never distributed.
• 2011 - U.S. Patent application for bulbous bluegrass hybrids for use commercially as a turf grass.
A. T. Bleak and A. Perry Plummer (1954)
1940 Seeding of bulbous bluegrass, crested wheatgrass, and beardless bluebunch wheatgrass north of Ephraim, Utah. (Picture taken between 1940 and 1954)
EDDMapS. 2013. Early Detection & Distribution Mapping System. The University of Georgia - Center for Invasive Species and Ecosystem Health. Available online at http://www.eddmaps.org/; last accessed September 30, 2013.
Distribution Map of Bulbous Bluegrass by County
Distribution Map of Bulbous Bluegrass
• Approximately 800 range trend sites.
• 128 range trend sites have sampled bulbous bluegrass
• UDWR range trend study sites are primarily located in Utah on mule deer winter range within big sagebrush habitat.
The map is based on range trend study sites
Bulbous Bluegrass Correlation Study• Observed decreases of sagebrush and increases of bulbous bluegrass• Decreases in sagebrush is a concern for wildlife• Designed a study to determine if there was a relation between sagebrush
and bulbous bluegrass
Bulbous Bluegrass Correlation Study• Used the log Response Ratio
– Compared the Daubenmire % cover of POBU, ARTR, and BRTE• log (POBU % cover/ARTR % cover)• log (POBU % cover/BRTE % cover)• log (BRTE % cover/ARTR % cover)
– Standardizes the relationship across sample sites and years
• Criteria for site selection– Both big sagebrush and bulbous bluegrass sampled on the site– No disturbance on the site following the establishment of the study
site
• Tested for three relationships– POBU:ARTR– POBU:BRTE– BRTE:ARTR
Bulbous Bluegrass and Big SagebrushLS Means Plot
R2 = 0.68
Probƒ = <0.0001
Time Period LS Mean Std Err
1992-1997 (1) C -2.900290 0.32
1998-2002 (2) B -1.420144 0.30
2003-2007 (3) A B -0.582367 0.29
2008-2012 (4) A 0.136140 0.31
Bulbous Bluegrass and Big SagebrushLS Means Differences Tukey HSD
• The more negative the LS Mean score the higher sagebrush cover is in relation to bulbous bluegrass
• The more positive the LS Mean score the higher bulbous bluegrass cover is in relation to sagebrush
Bulbous Bluegrass and CheatgrassLS Means Plot
R2 = 0.68
Probƒ = <0.0001
Time Period LS Mean Std Err
1992-1997 (1) B -0.117533 0.27
1998-2002 (2) A 2.427069 0.25
2003-2007 (3) A 2.569744 0.24
2008-2012 (4) A 3.591432 0.26
Bulbous Bluegrass and CheatgrassLS Means Differences Tukey HSD
R2 = 0.86
Probƒ = <0.0001
• The more negative the LS Mean score the higher cheatgrass cover is in relation to bulbous bluegrass
• The more positive the LS Mean score the higher bulbous bluegrass cover is in relation to cheatgrass
Cheatgrass and Big SagebrushLS Means Plot
Time Period LS Mean Std Err
1992-1997 (1) A -2.580578 0.38
1998-2002 (2) B -3.791087 0.35
2003-2007 (3) A B -3.080804 0.34
2008-2012 (4) A B -3.446897 0.37
Cheatgrass and Big SagebrushLS Means Differences Tukey HSD
R2 = 0.89
Probƒ = <0.0001
• The more negative the LS Mean score the higher sagebrush cover is in relation to cheatgrass
• The more positive the LS Mean score the higher cheatgrass cover is in relation to sagebrush
Old Pinery
1983
Old Pinery
1989
Old Pinery
1997
Old Pinery
2002
Old Pinery
2007
Old Pinery
2012
1997 2002
2007 2012
N. Frequency (Max of 500) or Density Cover
1997 2002 2007 2012 1997 2002 2007 2012
Bulbous bluegrass 64 246 346 320 1% 15% 29% 35%
Cheatgrass 259 259 317 170 2% 3% 9% 2%
Crested Wheatgrass 110 107 87 10 5% 6% 1% < 1%
Mountain Big Sagebrush(% Young)
2040 plants/acre(69%)
3340 plants/acre(35%)
2700 plants/acre(4%)
2220 plants/acre(6%)
6% 10% 13% 16%
Old Pinery Summary
• Sagebrush has increased in cover over the sample years, but has decreased in density since 2002
• Recruitment of young sagebrush plants has decreased over the sample years• Cheatgrass fluctuated in cover and frequency over the sample years• Crested Wheatgrass decreased substantially in cover and frequency• Bulbous bluegrass increased in cover and frequency over the sample years
North Wallsburg
1989
North Wallsburg
1996
North Wallsburg
2002
North Wallsburg
2007
North Wallsburg
2012
1996 2002
2007 2012
N. Frequency (Max of 500) or Density Cover
1996 2002 2007 2012 1996 2002 2007 2012
Bulbous bluegrass 181 348 363 384 8% 23% 24% 30%
Cheatgrass 370 232 358 293 16% 5% 9% 7%
Mountain Big Sagebrush(% Young)
2240 plants/acre(16%)
2540 plants/acre(5%)
1800 plants/acre(2%)
1620 plants/acre(1%)
9% 14% 11% 11%
North Wallsburg Summary
• Sagebrush has decreased in density and cover since 2002• Recruitment of young sagebrush plants has decreased over the sample years• Cheatgrass has fluctuated over the sample years• Bulbous bluegrass increased in cover and frequency over the sample years
Cedar Hollow
1984
Cedar Hollow
1990
Cedar Hollow
1996
Cedar Hollow
2001
Cedar Hollow
2006
Cedar Hollow
2011
1996 2001
2006 2011
N. Frequency (Max of 500) or Density Cover
1996 2001 2006 2011 1996 2001 2006 2011
Bulbous bluegrass 107 199 161 218 4% 5% 6% 11%
Cheatgrass 1 0 4 0 0% 0% 0% 0%
Mountain Big Sagebrush(% Young)
1900 plants/acre(7%)
1800 plants/acre(0%)
940 plants/acre(2%)
980 plants/acre(8%)
8% 8% 6% 6%
Cedar Hollow Summary
• Sagebrush has decreased in density and cover over the sample year• Recruitment of young sagebrush was minimal• Cheatgrass was minimal on the site• Bulbous bluegrass increased in cover and frequency over the sample years
Echo Canyon
1984
Echo Canyon
1990
Echo Canyon
1996
Echo Canyon
2001
Echo Canyon
2006
Echo Canyon
2011
1996 2001
2006 2011
*N. Frequency (Max of 500) or Density Cover
1996 2001 2006 2011 1996 2001 2006 2011
Bulbous bluegrass 58 85 160 310 1% 3% 5% 24%
Cheatgrass 330 169 179 128 14% 4% 5% 5%
Mountain Big Sagebrush(% Young)
3300 plants/acre(16%)
2780 plants/acre(0%)
1880 plants/acre(1%)
1180 plants/acre(2%)
14% 15% 10% 4%
Echo Canyon Summary
• Sagebrush decreased in density and cover over the sample years• Recruitment of young sagebrush plants has decrease over the sample years• Cheatgrass decreased in cover and frequency over the sample years• Bulbous bluegrass increased in cover and frequency over the sample years
Bulbous Bluegrass and Big SagebrushLS Means Plot
Bulbous Bluegrass and Big SagebrushLS Means Differences Tukey HSD
Bulbous Bluegrass and Cheatgrass LS Means Plot
Cheatgrass and Big SagebrushLS Means Plot
Bulbous Bluegrass and CheatgrassLS Means Differences Tukey HSD
Cheatgrass and Big SagebrushLS Means Differences Tukey HSD
Time Period LS Mean Std Err
1992-1997 (1) A -2.580578 0.38
1998-2002 (2) B -3.791087 0.35
2003-2007 (3) A B -3.080804 0.34
2008-2012 (4) A B -3.446897 0.37
Time Period LS Mean Std Err
1992-1997 (1) B -0.117533 0.27
1998-2002 (2) A 2.427069 0.25
2003-2007 (3) A 2.569744 0.24
2008-2012 (4) A 3.591432 0.26
Time Period LS Mean Std Err
1992-1997 (1) C -2.900290 0.32
1998-2002 (2) B -1.420144 0.30
2003-2007 (3) A B -0.582367 0.29
2008-2012 (4) A 0.136140 0.31
Conclusions• There is a relationship between bulbous bluegrass and sagebrush
– Decreases of sagebrush correspond to the increases of bulbous bluegrass.
– The study shows an increase of bulbous bluegrass abundance and distribution since 1982, as well as an increase in co ver of bulbous bluegrass in relation to sagebrush and cheatgrass since 1992.
• The study does not determine mechanisms of change.– Is the decrease of sagebrush due to increase of bulbous bluegrass?– Is the increase of bulbous bluegrass due to decrease in sagebrush?
• Need for further research to identify if bulbous bluegrass has an impact on sagebrush and other plant species.– Is bulbous bluegrass a problem?– If so how do we address this problem?– Is bulbous bluegrass a primary factor or a compounding factor to the
decrease of sagebrush?
Discussion• Hypotheses– Cheatgrass may be the disturbance in the plant
community allowing bulbous bluegrass to invade• The plant community may be more susceptible to
invasion by bulbous bluegrass when cheatgrass is present on the site
– Bulbous bluegrass may inhibit recruitment of young sagebrush plants
– Early growth characteristics may give bulbous bluegrass a competitive advantage,
– May limit soil moisture for other plant species
• I’d like to thank the UDWR in funding and supplying the data used for analysis of the bulbous bluegrass, sagebrush, and cheatgrass.
• I like to thank UDWR personnel K. Gunnell, J. Lane, D. Summers and J. Vernon for their help and input to this study.
• I like to thank T. Monaco and D. Turner who helped with the statistics and analysis for this project.
• I also would like to thank the members of my graduate committee F. Howe, J. Kurtzman, and N. Mesner for their critiques and direction for this project
Credits
Any Questions?