IAG Guide Draft

Thinking Like A Weed Ecologist HOW TO LEVERAGE ECOLOGY TO MANAGE INVASIVE ANNUAL GRASSES IN WESTERN RANGELANDS

A Discussion Support Guide

How To Use This Guide We created this guide to empower you to think like a weed ecologist. Our goal is to support you in making informed, strategic invasive annual grass management decisions that defend your core values on the landscape. The guide mimics a conversation with an expert, asking you to consider the ecological context, recovery potential, and management toolbox for your site. It is designed for use at a project scale, ranging from a few to many acres.

We highly recommend talking through these questions with others. You can use quantitative information (e.g., monitoring or remotely sensed data), qualitative information (e.g., expert opinion and field observations), or both to support our responses. You do not need to answer every question to make a decision, but we recommend that, at a minimum, you have a good idea of your site’s recovery potential (Step 3) before taking action. You also may need help to answer some of the questions in this guide. We recommend seeking additional resources online or in person. Some suggested sources are included on the back cover.

Our Partners

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Step 1: Setting Up For Success Question 1A. What are your goals for the site? How will you know when you have succeeded?

Consider short- and long-term goals and how long you are committed to working towards them.

Your goals may be quantitative (e.g., cheatgrass cover below 10%), qualitative (e.g., increase forage for spring pasture), or both.

Determine the level of monitoring needed, from photo points to an intensive data collection effort, to know you have reached your goals.

Question 1B. Where are your core areas?

What values on the landscape do you want to defend or grow? Where are these values, or core areas, on your site?

Question 1C. Who needs to be involved?

Do you need to engage any additional partners before you get started?

Box 1. What Does It Mean to Defend and Grow Your Core?

Core areas refer to places on the landscape where highpriority values exist. It is up to you to define what values are high priority, and therefore what areas constitute core areas.

High-priority values may include intact sagebrush rangelands, areas of importance to wildlife, recreation areas, human communities, wetland and riparian areas, and more.

People use a variety of approaches to identify core areas, from formal modeling efforts like the Sagebrush Conservation Design, to getting together in a group and drawing circles on a map. What’s important is identifying the values you want to defend and grow and where they are on the landscape.

A little extra room here...

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Box 2. Information Sources for Learning About Your Site People use many sources of information to inform site context and recovery potential. We primarily rely on the following sources, leveraging both quantitative and qualitative data. We recommend using a combination of sources.

Photo points: Visually and efficiently capture conditions over time.

Site visits: Identify species present, assess factors affecting site conditions.

Remotely sensed data: Compare trends over time and at scale.

Plot-based data: Quantitatively asses vegetation composition and trends.

Step 2: Characterizing Invasion and Ecological Context Question 2A. How invaded is the site?

What is the abundance and spatial configuration of invasive annual grasses? Are they Where are areas of concern relative to your core areas?

Question 2B. Which invasive grasses are present?

Are there other weeds present?

Question 2C. Do you have knowledge of trends in invasive annual grass populations?

Are they increasing in cover or density, or stable?

Do you have a new invasive annual grass species?

Question 2D. What factors may be causing or exacerbating invasive annual grass abundance or desired species decline?

Consider how land uses, management actions, or other factors like wildfire or drought may increase invasive annual grasses or act as vectors and what (if anything) you can do to address them.

Consider the risk of conversion to an invasive annual grassdominated system if disturbance were to occur.

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Figure 1. Understanding Invasion & Ecological Context As you talk through Steps 1 & 2, use the scenario below as an example of identifying core areas and the characteristics of invasion at a site. A variety of methods (Box 2) can be used to inform these steps. We recommend using a combination of these methods, combining their strengths. To visually represent core areas and other features on the landscape, we find drawing polygons on printed or virtual maps to support productive conversations. Ultimately, you should have a pretty good idea of where the “good guys” and “bad guys” are on your landscape.

① Highly invaded areas. Potential seed source. ② Transmission lines. Potential fire risk, invasion pathway. ③ Core area: valley bottom grassland. Low-level invasive

annual grass infestation. Concern about adjacent seed sources and fire risk.

Roadside annual grass infestation. High-density invasive annual grass patch. Risk to surrounding intact areas.

Road. Potential invasion pathway. Fuel break.

Recent burn scar. Increasing invasive annual grasses and declining desired species. Invasive annual grass seed source.

Core area: intact sagebrush. Robust perennial grasses and forbs. Concern about adjacent seed sources and fire risk.

④ ⑤ ⑥ ⑦

① ② ③ ④ ⑥

⑤

⑦ -4-

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Step 3: Assessing Recovery Potential Question 3A.‌‌What is your site’s recovery potential?‌ What w‌ould be left if you removed or reduced invasive grasses (Box 3, Figure 2)? Is this plant community sufficient to meet your goals from Question 1A?‌ Consider functional groups present: Deep-rooted perennials, rhizomatous grasses, bunchgrasses, perennial and annual forbs, etc. What is present and what is missing?‌ Are you seeing declines in desired vegetation? If so, why?

Question 3B.‌‌What abiotic and biotic factors at your site might affect recovery?‌‌‌ Consider abiotic factors that may affect recovery, such as elevation, precipitation amount and timing, topography, and other variables.‌ Consider biotic factors that may affect recovery, such as livestock and wild ungulate grazing and the presence of other invasive species.‌ ‌

Question ‌3C.‌‌Given your responses to 3A-C, how‌ likely is recovery of desired vegetation at your site?‌‌ What management approach (m‌aintain, recover, or restore) best fits your recovery potential in Figure 2?

Do your goals in Question 1A align with the recovery potential of your site? Will you be able to defend or grow your core areas?‌ What are the barriers to recovery, and can you influence them with management?

Box 3. What Is Recovery Potential?

Recovery potential refers to the presence of desired plants on the site that will facilitate passive recovery if invasive annual grasses are removed or reduced.

To assess recovery potential, you can use plot-based or remotely sensed methods. We recommend visiting the site during the growing season to look at all layers of vegetation, including what may be hiding beneath the weeds and litter.

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Figure 2. Assessing Recovery Potential Use this figure, along with Box 3, to understand recovery potential. Sites with high abundance of desired species have high recovery potential, while sites with low abundance of desired species have low recovery potential, regardless of abundance of invasive annual grasses. Your management approach should be tailored to your recovery potential: Maintain: When recovery potential is high, but invasive annual grass abundance is low, recovery is not needed. Actions should maintain current conditions.

Recover: Above the recovery potential threshold, recovery is likely using passive methods. Where invasive annual grasses are present, actions should recover desired vegetation.

Restore, Contain, & Accept: When recovery potential is low and invasive annual grass abundance is high, passive recovery may not be possible. Actions may restore desired species, or contain or accept invasive annual grasses.

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Step 4: Building Your Management Toolbox Question 4A. What’s in your toolbox?

What are the management tools (Figure 3) that are available to you based on the approach you identified in Question 3C?

Question 4B. How can you align your management tools with the biology of the invasives present?

What part of the invasive annual grass lifecycle in Figure 4 can your potential approaches interrupt? How should the timing of your approach be tailored to that lifecycle?

Figure 3. Identifying Your Management Toolbox MAINTAIN Lowest cost, quickest results Monitoring Herbicide: Spot spraying

RECOVER

Moderate cost, greatest recovery potential

Herbicide: Broadcast spraying Seeding: Native seeds

RESTORE, CONTAIN, & ACCEPT

Mowing Targeted grazing

Highest cost, slowest results, lowest probability of recovery

Containment Herbicide: Broadcast spraying Seeding: Non-native seeds

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Prevention (minimizing disturbance, managing invasion pathways)

Mowing Targeted grazing Intensive restoration: Extensive application of multiple approaches

Figure 4. Hacking the Invasive Annual Grass Lifecycle

FALL

PREVENT SEEDLING EMERGENCE AND REDUCE THE SEEDBANK

Pre-emergent herbicides applied in the fall by prevent germination to reduce the next year’s population.

Targeted grazing reduces the seedbank and removes fine fuels.

WINTER

TREAT SEEDLINGS AND REDUCE FINE FUELS

INDAZIFLAM Pre-emergent herbicide IMAZAPIC, RIMSULFURON, SULFOSULFURON Pre- and post-emergent herbicides GLYCOSPHATE Post-emergent herbicide TARGETED GRAZING

Post-emergent herbicides applied in the winter when desired species are dormant can reduce the next season’s invasive annual grass population. Targeted grazing removes fine fuels and reduces litter.

SPRING

TREAT SEEDLINGS AND REDUCE SEED PRODUCTION

Pre- and post-emergent herbicides applied in the spring target spring emergence and established seedlings, respectively. Targeted grazing reduces seed production and takes advantage of good forage quality.

SUMMER

PREVENT GERMINATION WITH EARLY HERBICIDE APPLICATION

Applying pre-emergent herbicides in summer can ensure that herbicide is present in the soil when precipitation occurs and before germination begins.

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Step 5: Next Steps Towards Your Management Plan Question 5A. From Steps 1-4, are there areas where you might need more information? Help?

What local resources are available to help you? Consider county weed and pest districts, NRCS offices, university extension, conservation districts, or licensed applicators.

List what you need to do to fill these information or knowledge gaps.

Question 5B. What appropriate management approaches are you considering?

What are your best options? Can you debate the pros and cons of each with your project partners?

What resources are available to help you fund or implement these options?

Question 5C. What are three steps you can take now to help you move towards action?

Additional Resources