A BIOGEOGRAPHIC CONTRAST OF FACTORS INFLUENCING INVASIVE SPECIES ABUNDANCE IN NATIVE VS NON-NATIVE RANGES

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: ACTIVE
• Funding Source: AFRI COMPETITIVE GRANT
• Reporting Frequency: Annual
• Accession No.: 1028355
• Grant No.: 2022-67020-37647
• Cumulative Award Amt.: $649,972.00
• Proposal No.: 2021-09759
• Project Start Date: Jul 1, 2022
• Project End Date: Jun 30, 2026
• Grant Year: 2022
• Program Code: [A1451]- Renewable Energy, Natural Resources, and Environment: Agroecosystem Management

Recipient Organization
UNIVERSITY OF MONTANA
COLLEGE OF FORESTRY AND CONSERVATION
MISSOULA,MT 59812

Performing Department
Animal and Range Sciences

Non Technical Summary
SummaryRangelands support the pastoral livelihood and food security of billions of people globally while providing crucial ecosystem services,such asbiodiversity and primary productivity. However,widespread biological invasions by exotic plant species are degrading the biodiversity and ecosystem functioning (BEF) of rangeland systems at tremendous economic costs, creating an urgent need for management actions that provide sustainable solutions to rangelandplant invasions.Understanding the ecological processes that drive plant invasions is the crucial first step towards sustainable control.A powerful approach for gaining this understandingis to experimentallyevaluate how biotic and abiotic processes affect invasive species in their native vs. non-native ranges.This biogeographical approach poises land managers to control plant invasions by either mimicking population controls that are more effective in the native range, or by disrupting positive feedbacks present mainly in the non-native range.However,the vast majority of studies on invasive species ecology and management have been conducted solely within the non-native range of invaders, where they are most problematic and behave much differently than in their native range.This lack of biogeographical context limits our fundamental knowledge of plant invasions and perpetuates the difficulty of sustainably controlling rangeland weeds. Following this, the overarching goal of our proposal is to use an experimental, biogeographical approach to advance our mechanistic understanding of how biotic and abiotic processes contribute to the invasion and sustainable control ofBromus tectorum- an annual grass native to Eurasia but exotic and extremely invasive across western North American rangelands.Our primary research objectives are to: 1) Quantify how biotic (insect herbivory, plant-fungal interations, cattle grazing) and abiotic (fire, mechanical soil damage) processes independently and jointly affectB. tectorumabundance and BEF in the native (Eurasia) and non-native (USA) ranges; and 2) Identify combinations of management actions that lead to sustainable, process-based management of localB. tectorumabundance and BEF.To achieve our first objective, we will replicate simultaneous, coordinated experiments in actively grazed, multi-use rangelands in the native (Italy, Hungary, Iran) and non-native (Utah, Nevada, Idaho, Oregon) ranges ofB. tectorum. These experiments will manipulate key biotic (plant-fungal interactions, insect herbivory, cattle grazing) and abiotic (fire, mechanical soil damage) processes. To achieve our second objective, we will develop a straightforward graphical tool that clearly depicts the effects of experimental treatment combinations (which can be thought of as possible management actions) on B. tectorum abundanceand BEF simultaneously. This proposed research will increase our fundamental understanding of the ecological processes that driveB. tectoruminvasion and BEF in local plant communities, and then translate this basic understanding to adaptive management actions that controlB. tectorumabundance whileincreasing BEF. To accomplish our objectives, we have assembled a dynamic team of international collaborators based in the native (Eurasia) and non-native (USA) ranges ofB. tectorum, with decades of collective experience conducting biogeographical research on the ecology and management of invasive plant species. We will maximize gains on our research by creating an advisory committee with members from diverse organizations, including international non-governmental organizations, federal and state land managers, private landowners, and range professionals. We will seek ongoing guidance from the advisory committee on the feasibility of the basic and applied components of our project, as well as the most effective outlets for disseminating our findings.

Animal Health Component

60%

Research Effort Categories

Basic

40%

Applied

60%

Developmental

0%

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
121	0799	1070	100%

Knowledge Area
121 - Management of Range Resources;

Subject Of Investigation
0799 - Rangelands and grasslands, general;

Field Of Science
1070 - Ecology;

Keywords

insect herbivory

sustainable control of¿bromus

cattle grazing

plant-fungal interactions

Goals / Objectives
The overarching goal of our proposal is to use an experimental, biogeographical approach to advance our mechanistic understanding of how biotic and abiotic processes contribute to the invasion and sustainable control ofBromus tectorum --an annual grass native to Eurasia but exotic and extremely invasive across western NorthAmerican rangelands.Ourprimary research objectives are to:1)Quantify how biotic(insect herbivory, plant-fungal interactions, cattle grazing) and abiotic (fire, mechanical soil damage) independently and jointly affectB. tectorumabundance and subsequent biodiversity and ecosystem functioning (BEF) in thenative (Eurasia) andnon-native (USA) ranges; and2)Identifycombinations of management actions that lead to sustainable, process-based management of localB. tectorumabundance and BEF.Thisproposed research will increase our fundamental understanding of the ecological processes that driveB. tectorumabundanceand BEF in local plant communities,and then translate thisbasic understanding to adaptive management actions that achieve particular goals - for example, simultaneously decreasingB. tectorumabundance and increasing BEF.

Project Methods
Site DescriptionOur project requires simultaneous, coordinated field experiments replicated in the native (Eurasia) and non-native (USA) ranges ofB. tectorum.Study sites in Eurasia will be placed in Italy, Bulgaria, andIran; and study sites in the USA will be placed in Nevada, Utah, Idaho, and Oregon. Experimental DesignWe will quantify the independent and joint effects ofplant-fungal interactions,insect herbivory,cattle grazing,fire,andmechanical soil damageonB. tectorumabundance and key aspects of biodiversity and ecosystem functioning (BEF)by replicating full-factorial experiments at three study sites in Eurasia (n=3) and five study sites in the USA (n=5). Each study site will be comprised of three, 26 x 44 m experimental replicates (i.e., blocks) in which the biotic and abiotic processes named above will be manipulated in all possible combinations. Each replicate will consist of four, 10 x 18 m plots - subdivisions grouped for logistical convenience when applying cattle grazing and fire treatments. Specifically, one plot will be unburned and protected from cattle, one will be unburned and open to cattle, one will be burned and protected from cattle, and one will be burned and open to cattle. Each plot will consist of eight, 2 x 2 m subplots. Plant-fungal interactions, insect herbivory, andmechanical soil damage will be manipulated independently and/or jointly within these subplots.Bromus tectorumabundance and key metrics of BEF will be measured at the subplot level.Plant-fungal interactionsandinsect herbivorywill be manipulated with chemical pesticides applied at regular intervals through the growing season. We will use chlorothalonilandtebuconazoleto manipulate plant-fungal interactions, and we will use bifenthrin to manipulate insect herbivory. Fungicides and insecticides will be applied 4 times/year (April, June, August, October) in years 1-4of the project.Cattle grazingwill be manipulated by installing barbed wire fencing. All site locations will be on actively grazed rangelands. Plots with cattle excluded will be fenced on all sides, and plots with cattle present will be fenced on two sides. Our 2-m boundary between fence lines and subplots within plot boundariesameliorates edge effects associated with fence installation and maintenance.Fencing will be installed once (in October of year 1) but will operatecontinuously forthe duration of the project.Firewill be manipulated by imposing a one-time burn treatment in year 1 of the project. Burns will occur inOctober to coincide with the natural timing of wildfire.Mechanical soil damagewill be manipulated by imposing a one-time hoeing treatment to a depth of 10-15 cm in October of year 1 of the project. Soil disturbance treatments will occur only once to avoid repeatedly turning over the soil and killing plants.These treatments will be performed on background plant communities and experimentalB. tectorumpopulations established by seeding. Prior to the initiation of any experimental treatments, each 2 x 2 m subplot, including control subplots, will be sown at a rate of 10,000B. tectorumseeds/m2, which translates to a "medium-high" level of invasion for western North American rangeland. Seeding will occur in October of year 1.Response measuresWe will quantify the effects of experimental treatments onB. tectorumabundance and key metrics of BEF with widely used and management-informative response measures. We will evaluate effects on plant communities using vegetation surveys. In the center of each 2 x 2 m subplot, we will place a 50 x 50 cm sampling quadrat and record the abundance of all species present. For vegetatively propagating species, we will count stem density. We will only record living plants. We will use these species-specific counts to tabulate species richness, functional group diversity, and Shannon's diversity index. In each subplot, we will also estimate species cover using the pin drop methodat 10 cm increments along a 2 m transect running lengthwise from east to west through the subplot center. These surveys will be conducted in May of years 1-4 of the project.To evaluate the effects of experimental treatments on key aspects of ecosystem function, we will measure total soil Nitrogen (N), soil organic carbon (SOC), and standing aboveground biomass. For soil-based measures, we will take a 5 x 5 x 5 cm soil core from the four corners of each subplot. We will aggregate these soil cores at the subplot level and calculate soil N and SOC using a combustion method after acid treatment. Soil N and SOC will be measured in October of years 1-4 of the project. For standing biomass, we will harvest all aboveground biomass growing within a 50 x 50 cm quadrat placed in the center of each subplot. Biomass will be dried to constant mass and then weighed (g). Standing biomass will be harvested and measured in October of year 4 of the project.Effects of experimental treatments can be expressed as changes in the value of a response measure (ΔX) as follows:ΔX =Xt- X0whereXtis the value of a response measure (e.g.,B. tectorumabundance) under a particular combination of experimental treatments, andX0is the value of the same response measure in the absence of treatments (i.e., no fungicides, insecticides, fencing, fire, or soil disturbance). Thus, ΔX> 0 indicates positive treatment effects,ΔX= 0 indicates neutral effects, andΔX< 0 indicates negative effects.Statistical approachWe will analyze our data with linear mixed-effects models. We will analyze each response measure (specified in Table 4) independently. Each model will fit fungicide, insecticide, fencing, fire, soil disturbance, and range (native vs. non-native) as fixed effects; and replicate (a blocking factor) nested within study site as a random effect. This model structure is appropriate for all response measures and elucidates the independent and joint effects of experimental treatments on response measures. Any biogeographical differences in the effects of experimental treatments will be reflected in significant statistical interactions involving range. Responses that do not conform to a normal distribution will be fit to a quasi-Poisson distribution.

Progress 07/01/23 to 06/30/24

Outputs
Target Audience:The primary target audience for this specific reporting period, are University of Montana Natural Resources undergraduatestudents, as well as agency personnel and private stakeholders. For students,the project level field efforts were directly applicablefor professional development purposes to learn about Rangeland Management and Invasive Species Management and Biology across different locations invaded by cheatgrass. Agency and private stakeholder target audienceswill continue to be communicated with throughout the funding cycles with the greatest communications lines in placethrough the dissemination of theresults. That said, even in this early stage of project level installation, we are communicating directly with agency personnel regarding our fire applications, for example,as well as the private landowners regarding cheatgrass invasion management. Changes/Problems:The Nevada field site installation, monitoring, and upkeep was implemented following established protocols and timelines. This, thanks to all personnel involved was great to accomplish. Our Tensleep WY site was set to have all treatments implemented in mid-October 2023 as noted in the proposal, however, as the fire crew was setting up for the burning treatment, they had a major snow storm that added inches of snow to our field site. This was a season ending event and thus we were not able to initiate the expected treatments at our Wy sites. We have mitigated this event setback by setting up and staging fencing to the best of our abilities and then re-collecting pre-treatment vegetation and soil data in the peak growing season of 2024, with the expectation to initiate treatments in October of 2024. What opportunities for training and professional development has the project provided?Within this reporting period, we have maintained opportunities for our post-doctoral scholar, and the TAMU PhD student. Specifically, this position has provided Talia the opportunity to work with international collaborators, mentoring undergraduate and graduate students, and foster her independent research. Ande Peerson joined the project as the Technician and is working for the Faist Lab at the University of Montana, where she has overcome many climate and logistical challenges to achieve the timely instillation of this broad project and allowed her to build a network of individuals across private and state agencies in different fields (e.g., county fire to TNC personnel). This project has also continued to provide a learning resource for three undergraduate students from the University of Montana who joined the project as summer casual student workers. In addition to learning core science and monitoring skills (e.g., collecting soil cores for chemical and microbial analysis, and conducting cover and line point intercept vegetation surveys), two of the technicians used the opportunity provided in the field for internship credit through the University of Montana Ecosystem Science and Sustainability degree program during this reporting period. The internship included writing a reflection piece on their experience working on the project and PI Faist was able to guide their internship experiences through writing edits on the reflection piece, and reflection discussions and what that meant for their careers. Additionally, these students are majoring in ecology related degrees, and this project has contributed directly to their broader learning experience. How have the results been disseminated to communities of interest?With the project primarily in the pre-treatment and initial treatment implementation and monitoring phase, we do not have results to report just yet. That said, we as a project leadership group acknowledge the importance of communication throughout the project. Thus, we have continued to work directly with agency (e.g., Bureau of Land Management), private (Nevada Gold Mine and TNC), and university personnel to ensure that they are updated on our efforts and with the line of communication already in place, will work to quickly disseminated findings after they come in and are summarized. Our international collaborators are also working on building connections with regional Institutions and personnel. What do you plan to do during the next reporting period to accomplish the goals?For our next reporting period we plan to continue to maintain our site level upkeep across all sites and ensure professional development of individuals associated with the project. For instance, with all three NV sites in place with all treatments, as well as treatment upkeep, maintained, we will continue to maintain our data management efforts and ensure following year data collection are streamlined for the following monitoring years. We also plan to continue to guide the TAMU PhD student used with unrestricted outside leveraged funds to help them not only maintain the project level efforts, but also build PhD level expertise in the field of Rangeland Sciences. On a practical side, we also hope to continue to communicate with local, regional, national, and international personnel to potentially identify if new site installation is possible to further leverage this study design.

Impacts
What was accomplished under these goals? Within this reporting period to meet our major goals of the project, we completed site installation, maintenance of plots,and initial summer vegetation surveys for both 2023 and 2024 primary growing seasons. We have secured and maintained ample personnel to work directly on this project, including; a Post Doctorate Research Associate, a technician, greater than three undergraduate student workers, and leveraged a PhD student to work on the project through outside funding. Further, within the reporting period, we established and maintained important relationships with land managers from Nevada Gold Mines and the Wyoming Nature Conservancy to gain permission to conduct this research on their lands. Following the site level installations in the summer of 2023, we collected post treatment data in the form of vegetation surveys and core soil samples across all NV field sites. Our spring of 2023 collected B. tectorumseeds were added to the plots at the time of treatment installation in October of 2023 for all NV sites. In addition to seeding, all additional designated treatments were initiated in October for 2023. This includedboth the USA and in European sites, implementing the treatments of fire, fencing, insecticide, fungicide and soil disturbance in early October.After successful installation and treatment implementationof the NV field sites, as well as our European counterparts locations,we also ensured upkeep of our NV sites in April of 2024 as noted in the goals (e.g., spraying fungicide and insecticide on respective treatment plots).We have also maintained and established our collaboration with several European institutions, including CABI and BBCA, who will continue contribute to answering the biogeographic questions surrounding this project. With the first reporting calendar setting the foundation of this research project through site level installation, this second reporting period allowed us to collect pretreatment baseline vegetation and soil data, as well as implement and maintain the multifactorial treatments across all of our Nevada sites.

Publications

• Type: Journal Articles Status: Accepted Year Published: 2024 Citation: Humphries T, Faist AM, Callaway RM, Lucero JE. 2024 (in press). The hotter the better: Increasing temperature, not seed predation, hastens the decline of invasive Bromus tectorum across climax sage-steppe communities. Biological Invasions. Accepted manuscript available upon request.

Progress 07/01/22 to 06/30/23

Outputs
Target Audience:The target audience of this effort for this reporting period, are University of Montana students as well as agency and private stakeholders. For students, the technical work that needed to be completed was complimented by using the project level install for professional development purposes to learn about Rangeland Management and Invasive Species Management and Biology.The target audience of the stakeholders will continue throughout the funding cycles with the primary delivery after results are obtained, but even in this early stage of project level installation, we are communicating directly with agency and private stakeholders to ensure our efforts are applicable throughout the process. Changes/Problems:While this was a very high precipitation year and site installation was delayed a few days, or personnelhad to be shuffleddepending on the site, these were not outsideof normal project related activities, and we were able to maintain our schedule within reason and there are no major changes to our project at this time. What opportunities for training and professional development has the project provided?Within this reporting period, we have sourced and placed two individuals into full-time positions for this project, one Post Doctorate Research Associate and one Technician. Talia Humphries joined this project in the role of the Post Doctorate Research Associate, and is working from the Lucero Lab at Texas A&M University. Talia joins us from Federation University Australia, where she had recently completed her Doctorate of Philosophy in the scope of weed ecology and ecological restoration. This project has offered Talia the opportunity to further develop the skills she needs to develop her career and move towards her goal of achieving a professional position.Specifically, this position has provided Talia the opportunity to work with international collaborators, mentoring undergraduate and graduate students, and foster her independent research. Ande Peerson joined the project as the Technician and is working for the Faist Lab at Montana University, where she has overcome many climate and logistical challenges to achieve the timely instillation of this broad project. This project has provided a learning resource for three undergraduate students from Montana University who joined the project as summer casual student workers. The students Lydia, Ben and Patrick assisted Talia and Ande with the installation of the plots, collecting soil cores for chemical and microbial analysis, and conducting cover and line point intercept vegetation surveys. The students quickly adopted excellent plant identification skills and maintained positive attitudes throughout the duration of the fieldwork. These students are majoring in ecology related degrees, and this project has contributed directly to their broaderlearning experience. How have the results been disseminated to communities of interest?With the project in the initial installation phase, we do not have results to report just yet. That said, we as a project leadership group acknowledge the importance of communication throughout the project. Thus, we have worked directly with agency (e.g., Bureau of Land Management), private (Nevada Gold Mine), and university personnel to ensure that they are updated on our efforts and with the line of communication already in place, will quickly disseminated findings after they come in and are summarized. What do you plan to do during the next reporting period to accomplish the goals?With this reporting period primarily being focused on hiring key personnel, the initial installation of the multiple sites across our study areas, and collecting baseline plant and soil data, we are prepped and ready for the treatment installation to be conducted during the month of October. Here, directly in schedule with the project narrative, we have the personnel in place to employ our different treatments. For instance, as noted, we are working directly with fire personnel to effectively, and safely implement the burn treatment. We have also created and shared across all parties, a detailed protocol list of how to standardize our treatments, and in what order, to ensure every installation can be compared with one another for maximum efficacy. We also have purchased, and ensured PPE is in place, for each treatment to not only employ the treatments in a standardized manner, but safely so. Finally, fencing is staged at the sites and is in the schedule to install to once again, ensure all projected treatments can be implemented in the necessary timelines. We also have communicated our data management plan and preliminary data are being entered, checked, and stored following that management plan, and will continue to do so. After this big initial installation push, we also have the personnel and protocol in place for subsequent sampling efforts to ensure data collection can be done as proposed.

Impacts
What was accomplished under these goals? Within this reporting period to meet our major goals of the project, we have secured all of the key materials, resources and personnel that are imperative to the success of this ongoing research project. We have secured ample personnel to work directly on this project, including; a Post Doctorate Research Associate, a Technician, a PhD candidate, and three casual undergraduate student workers. Further, within the reporting period, we established important relationships with land managers from Nevada Gold Mines and the Nature Conservancy to gain permission to conduct this research on their land. After successfully scoping suitable sites for this experiment at each location, those being near; Midas, NV; Carlin, NV; Oasis, NV; and Tensleep, WY, we completed the installation of the experimental plots across all four sites. Following the installation, we collected pre-treatment data in the form of vegetation surveys and core samples. Seeds were collected from mature B. tectorum plants of local provenance to each of the four sites. Seed viability was tested under glasshouse conditions, and if not 100%, nearly so, germination was achieved across all populations. We have also maintained and established a collaboration with several European institutions, including CABI and BBCA, who will contribute to answering the biogeographic questions surrounding this project. Across both the USA and in European sites, we are aiming to implement the treatments of fire, fencing, insecticide, fungicide and soil disturbance in early October, and efforts have been made during this reporting period to ensure the resources and materials required are available to achieve this. For instance, the project technician, Ande, has secured an ongoing relationship and assistance from local fire departments from north Nevada and Tensleep, WY to complete one of our most logistically complex treatments, thefire treatment, in October, 2023. Within this first reporting calendar we have achieved setting the foundation of this research project, and completed the required steps to ensure the treatments will be ready to install in October, 2023.

Publications

• Type: Conference Papers and Presentations Status: Published Year Published: 2023 Citation: 2023 Lucero JE. Plant ecology in changing rangelands. Department of Rangeland, Wildlife and Fisheries Management Convocation, Texas A&M University, College Station, TX
• Type: Conference Papers and Presentations Status: Published Year Published: 2023 Citation: 2023 Lucero JE. Understanding patterns of biodiversity and their underlying processes. State of Texas 4-H Roundup, Ecology and Natural Resource Teaching Area, Texas A&M University, College Station, TX