Download presentation
Presentation is loading. Please wait.
Published byRhoda Ball Modified over 6 years ago
1
Management of cheatgrass fuel loading in the shrub-steppe
Steven O. Link, PhD (Botany) Native Plant Landscaping and Restoration LLC 4604 E. Robin Ct. West Richland, WA 99353 and Department of Science and Engineering Confederated Tribes of the Umatilla Indian Reservation 46411 Timine Way Pendleton, OR 97801
2
Acknowledgement This work was funded by the Joint Fire Science Program. The work was done in cooperation with the Mid-Columbia River National Wildlife Refuge Complex. Special thanks are given to Randy Hill for help defining the questions and for continued technical support.
3
Bromus tectorum cover mapping and fire risk
Effect of herbicide and herbicide concentration on Elymus wawawaiensis establishment in the shrub-steppe Management of fuel loading in the shrub-steppe: Responses six, seven, and eight years after treatments Fire risk in replanted bunchgrass communities
5
Bromus tectorum cover mapping and fire risk
6
Bromus tectorum infestation at the Saddle
Mountain element of the Hanford Reach National Monument
7
High Bromus tectorum fuel load
8
Low Bromus tectorum fuel load
9
Lack of continuous fuel limits fire
10
Experimental Design The fire risk experiment was in plant communities that spanned the range of B. tectorum cover. Bromus tectorum cover was grouped into five classes. Each replicate is comprised of 8 to 18 plots in the three lowest B. tectorum cover classes and 2 to 6 plots at the two highest cover classes. A replicate is a collection of plots where the risk of fire was determined as the proportion of plots that burned. Each class has four replicates. We used 176 square plots, 10 m on a side. Two hundred twenty six plots, 10 m on a side, were used to related B. tectorum cover to color band intensity.
14
Conclusions • Bromus tectorum cover can be mapped using aerial color band reflectance photos taken in late summer. • Based on the B. tectorum cover map and the relationship between B. tectorum cover and fire risk, fire risk can now be mapped.
15
Effect of herbicide and herbicide concentration on
Elymus wawawaiensis establishment in the shrubsteppe
16
Field site at the Columbia National Wildlife Refuge
17
Prescribed Burn
18
Herbicide Application
19
Bunchgrass Drill Seeding
Elymus wawawaiensis (Snake River wheatgrass, Secar cultivar) was drill seeded at a rate of about 7 lb. acre-1 on Feb. 19, Drill rows were 0.3 m apart.
20
Roundup - 2 oz/acre
21
Plateau - 2 oz/acre
22
Plateau - 4 oz/acre
23
Plateau - 8 oz/acre
25
Management of fuel loading in the shrub-steppe: Responses six, seven, and eight years after treatments
26
Our objective was to determine if our strategy to reduce Bromus tectorum cover and thus fire risk is sustainable after implementation. We tested three hypotheses reporting results for 2008, 2009, and 2010. Hypothesis 1: Bunchgrasses established in 2003 will show an increasing degree of B. tectorum control over three years (2008, 2009, 2010). Hypothesis 2: Native species richness and cover in Plateau plots will not be different from controls 6, 7, and 8 years after treatment. Hypothesis 3: Alien species cover in Plateau plots will not be different from controls 6, 7, and 8 years after treatment. We monitored populations, flowering, and size of established bunchgrasses. We documented new E. wawawaiensis arising from self-seeding.
27
Figure 1. Eighteen years after drill seeding, E
Figure 1. Eighteen years after drill seeding, E. wawawaiensis, results in near elimination of B. tectorum.
32
Figure 4. Alien species cover from 2004 through 2010
Figure 4. Alien species cover from 2004 through The slope of the linear regression over time was significantly (p = ) greater than zero.
34
Figure 10. The relationship between E
Figure 10. The relationship between E. wawawaiensis canopy volume and the interference distance with B. tectorum.
38
Figure 7. Elymus wawawaiensis 8 years after seeding showing senescence (gray tillers) with remaining green tillers mostly near the edge.
39
Figure 8. Mean and predicted % senescent plants (± 1 sem) in the imazapic seeded plots.
40
Figure 9. Gray colored senescing E
Figure 9. Gray colored senescing E. wawawaiensis seeded in 1986 near the study area in 2009.
41
Figure 11. Relation between planted bunchgrass density and B
Figure 11. Relation between planted bunchgrass density and B. tectorum cover.
42
Fire risk in replanted bunchgrass
communities
46
Management Implications and Conclusion
We conclude that B. tectorum cover can be significantly and sustainably reduced by burning and applying Plateau herbicide at 4 or 8 oz acre-1 in the fall and then drill seeding E. wawawaiensis in the late winter. Seven years after treatment application the density of drill seeded E. wawawaiensis was 1.23 ± 0.24 plants m-2. Doubling the seeding rate may increase density enough to further reduce B. tectorum cover to be closer to the minimal value of 2.8% achieved with E. wawawaiensis density of 2.77 plants m-2.
47
Research Questions Examine viability of bunchgrass cultivars that arose from small initial populations leading to population bottlenecks that may reduce viability. Are locally sourced native plants more likely to sustain themselves. Examine the fire risk of more restored plant communities. What combination of species leads to significant reductions of fuel cover and increases in bare soil and soil cryptogams. Can Poa secunda provide sufficient interference to reduce Bromus tectorum cover?
Similar presentations
© 2024 SlidePlayer.com. Inc.
All rights reserved.