Browsing by Author "Pennings, Steven C."
Now showing 1 - 15 of 15
- Results Per Page
- Sort Options
Item Abiotic and Biotic Factors Shaping Plant-Microbe Interactions(2021-12) Locke, Hannah E; Crawford, Kerri M.; Pennings, Steven C.; Frankino, W. Anthony; Miller, Tom E. X.Symbioses between plants and soil microbes can shape plant traits and performance, population dynamics, community composition, and ecosystem function. However, the context-dependency of plant-microbe interactions remains an underexplored frontier of scientific understanding. Given that the biotic and abiotic contexts of ecological communities is rapidly shifting due to anthropogenic change, understanding the factors that shape plant-microbe interactions will allow us to make more accurate predictions of ecological interactions both presently and in the future. Here, we explore plant-microbe interactions across three different contexts—herbivory, ecological succession, and a water availability gradient. In each of these contexts we demonstrate of the importance of context dependency in shaping the outcomes of plant-microbe interactions. For example, in Chapter II, we found evidence that a multiple species mixture of mycorrhizal fungi in soils can facilitate aboveground herbivory, but only in the context of previous herbivory. The interaction between aboveground herbivory experiences and belowground microbial symbioses yielded entirely different directional outcomes for herbivore performance. In Chapter III, we explored whether soil microbes from three distinct ecological communities across a successional gradient differentially influenced plant defense strategies against herbivores. We found evidence that soil microbes from mid and late successional habitats increased plant capacity to reduce herbivore damage (resistance) but did not influence plant capacity to regrow after damage (tolerance). In Chapter IV, we pivot to assess an important abiotic context of plant-microbe interactions: water availability. We demonstrated through direct experimentation that the positive effect of mycorrhizae on plant performance increased as water availability increased. To our knowledge, is the first strong evidence that indicates the importance of mycorrhizae in facilitating the host plant’s ability to improve growth when provided ample water or even flooding conditions. In exploring the context-dependency of plant-microbe interactions, we gathered strong evidence that the biotic and abiotic environment shapes the outcomes of plant-microbes interactions ranging from negative (facilitation of aboveground herbivores) to positive (improved resistance against herbivores; increased biomass production in high water conditions). Taken together, this works emphasizes the need to incorporate variability in abiotic and biotic conditions into our understanding of ecological relationships between interacting species.Item Biophysical Feedbacks Mediate Tidal Creek Formation in Salt Marshes(2016-08) Vu, Huy 1985-; Pennings, Steven C.; Frankino, W. Anthony; Zufall, Rebecca A.; Wiernasz, Diane; Strom, Kyle B.How organisms and ecological systems respond to global change is of great interest to ecologists. These responses may or may not be beneficial because there might be positive or negative feedbacks that would make the impacts larger or smaller than expected. I conducted laboratory and field experiments to explore the mechanisms driving tidal creek formation in southeastern US salt marshes, focusing on three topics. 1) The effect of crabs on creek growth via four potential mechanisms: sediment excavation, plant removal, subterranean erosion, and decomposition. I found that Sesarma reticulatum (henceforth Sesarma) is the primary crab species mediating creek growth. Sesarma is concentrated at creek heads where plants are dying and creeks eroding. Sesarma excavated larger amounts of sediment through burrowing than other crabs, and is unique in creating burrow networks that likely increase belowground erosion and decomposition. Sesarma also is the only crab species that directly kills vegetation. Thus, Sesarma negatively impacts the marsh plant Spartina alterniflora and alters marsh geomorphology by engineering creek growth. 2) The factors mediating crab feeding preferences. I discovered that Sesarma did less damage to its food plant S. alterniflora in the presence of predators. Sesarma prefers and grows better consuming rhizomes than leaves; however, the cost of accessing rhizomes leads to higher mortality if rhizomes are the only diet option. A choice in feeding location allows Sesarma flexibility to balance the risks of predation, the nutritional benefit of feeding below-ground, and the survival costs of below-ground feeding. 3) The factors driving the aggregation and movement of Sesarma at creek heads. Creek heads are cooler, have higher dissolved oxygen levels, and lower hydrogen sulfide concentrations than elsewhere on the marsh. These superior conditions drive Sesarma aggregation. Additionally, I found that hydrology drives Sesarma aggregations when creek conditions were mimicked on the marsh platform. The results of this dissertation suggest that there is a biophysical feedback loop in marsh creek formation: creek growth is driven by a positive feedback between Sesarma crabs, which accelerate erosion, and creeks, which create abiotic conditions favorable for Sesarma crabs.Item Effects of Water Availability on Plant Coexistence through Altered Plant-Microbe Interactions(2017-05) Hawkins, Anna Patricia 1991-; Crawford, Kerri M.; Pennings, Steven C.; Armitage, Anna R.; Wiernasz, DianeThe biotic and abiotic factors that contribute to plant community structure and stability are of great interest to ecologists. A growing body of research suggests that interactions between plants and soil microbes contribute to coexistence within plant communities. The structure and function of the soil microbial community are highly context-dependent, so changes in abiotic factors could affect plant coexistence by altering the soil microbial community. However, few studies have examined this possibility. I conducted two experiments to test how water availability interacts with the soil microbial community to affect 1) the relative importance of interspecific and intraspecific competition between plant species and 2) plant-soil feedback. I centered my studies on plants commonly found in the Texas coastal prairie. I found that the presence of soil microbes increased the strength of intraspecific competition relative to interspecific competition, but their effect depended on water availability. As water availability increased in the presence of microbes, the strength of intraspecific competition decreased. However, this interaction was dependent on plant species identity. I also found that increasing water availability caused plant-soil feedback to increase from weakly negative to positive. The results of both of my studies suggest that interactions between the soil microbial community and increasing water availability could destabilize coexistence in plant communities. As ecosystems continue to experience changes in abiotic conditions due to ongoing anthropogenic climate change, it is essential to understand how those changes affect the interactions between plants and soil microbes in order to more accurately predict how plant community structure and stability will change in the future.Item Grazers vs Grazers: Large Mammal Herbivores Influence Salt Marsh Invertebrate Communities(2022-07-27) Lugar, Kori Jan; Pennings, Steven C.; Crawford, Kerri M.; Frankino, W. Anthony; Cronin, James T.Large mammals cause disturbances in the environments in which they graze by dramatically changing the physical structure of habitats. The response of plant and animal communities to megafaunal herbivory is highly variable among ecosystems, geographic location, and species of interest. Past research has often only focused on the response of a single taxa, and effects of grazing in North American salt marshes is relatively understudied. I conducted field studies on three barrier islands on the coast of Georgia, USA. Each island served as a site for one of three grazing treatments (cattle, feral horses, and artificial grazing by clipping). Treatment and control plots at the three sites were sampled for vegetation metrics and invertebrate abundance and diversity. All three grazing types altered invertebrate community composition, and each represented a different level of grazing intensity. Cattle grazing had a particularly negative impact on plant characteristics and the invertebrate community, while artificial grazing produced some opposite effects. Leaf chlorophyll content and toughness and invertebrate taxa such as snails (Littoraria irrorata) and Chaetopsis flies had varied responses, but plant height and katydid (Orchelimum fidicinium) density were consistently reduced by the three grazing types. To further investigate this, I performed two katydid feeding experiments and found that a more nutritious diet may not necessarily be more palatable. I also found that the response of planthoppers (Prokelisia spp.) to grazing correlates to the response of leaf chlorophyll content. The indirect effects of grazing on plant nutrition may therefore play an important role for herbivorous invertebrates. The responses of predatory invertebrates such as spiders are likely more dependent on the direct effects of grazing on vegetation biomass and architecture. The responses of different taxonomic groups and invertebrate communities to large mammal grazing and the underlying mechanisms should be considered when making livestock and land management decisions that aim to promote ecosystem functioning.Item How Does Grasshopper Feedings Vary Due to Nutrient Additions?(2017-10-12) Liu-Pham, Ryan; Prather, Chelse; Pennings, Steven C.We looked to explore the relationship between macro- and micronutrient addition on grasshopper feeding rates and their ability to detect the additions of these macro- and micronutrients in Schizachyrium scoparium. In previous studies, it has been determined that plant chemistry is a crucial factor in the feeding habits of herbivores. We then decided to look at whether or not a grasshopper could detect differences in plant nutrient availability by adding different nutrient combinations: Na, NP, NPCaNa, NPNa, and CaNa to grasses in the field. Then we conducted feeding trials to measure how these different nutrient combinations affected grasshopper feeding behavior. We hypothesized that Melanoplus femurrubrum will be able to detect the differences in plant nutrient content and would adjust feeding rates accordingly.Item Image Matching Web Interface Game(2013-05) Deshpande, Prachi 1984-; Hilford, Victoria; Garbey, Marc; Pennings, Steven C.Natural ecosystems are the backbone of human society. They support humanity's agricultural needs and provide clean air and water. However, environmental problems such as global warming and rising sea level created a strong urge to preserve natural ecosystem. The goal of the Virtual Prairie project is to study the fundamental mechanisms involved in regulating the population of plants in a prairie. The idea is to involve the general public in ecology projects, first training them in identifying prairie species and then allowing them to identify these species. The data generated are further processed to answer research questions such as how vegetation responds to variation in precipitation, effects of salt water on plant growth, etc. In an experiment conducted in Sapelo Island, Georgia, a large amount of data was recorded by digitally capturing images of a sampling area. The area was approximately 3,200 square meters and 3 to 4 images per square meters were acquired. Analyzing this large amount of spatially explicit digital data is impossible for a single scientist, creating a huge obstacle to progress of ecological studies. It would be helpful if the scientists were able to identify, for example, which plant species dominated over a few months, how it affected the animal community, what was the effect on their natural habitat, etc. Along with the detailed information that is available from the individual image, it is also advantageous to have a complete view of the entire marsh in order to understand the spatial relationships of different species. Therefore, stitching multiple overlapping images together to form a mosaic was necessary. However, applying automatic methods for image alignment and stitching did not produce accurate results because of the issues imposed by prairie images. Hence, the Image Matching Web Interface (IMWI) game was developed. IMWI is used as platform for users to be able to find matching points between pairs of images. We collect the data produced by the trained players playing on unprocessed images. These data will be used by a post-processing group to stitch the overlapping images together to form a mosaic of the marsh.Item Manipulation experiment overstates the competitive interactions occurring between mangroves and salt marsh vegetation(2022-04) Hockaday, Alyssa Cierra; Pennings, Steven C.; Crawford, Kerri M.; Nuñez, Martin A.; Armitage, Anna R.Ecologists use multiple methods for studying community-level interspecific competition, but different approaches may give different answers. We compared four methods to quantify the competitive interactions between Avicennia germinans (black mangroves) and salt marsh vegetation in Texas, USA. We compared four methods to quantify the competitive interactions between mangroves and marsh vegetation: two different methods of sampling a large (24 x 42 m) mangrove removal experiment, a transplant experiment conducted within the large experiment, and a natural experiment comparing sites naturally dominated by marsh or mangrove vegetation. We found stronger competition in the mangrove removal experiment than in the natural experiment. This was likely because the site chosen for the mangrove removal experiment had higher densities of mangroves than did the sites chosen for the natural experiment. Outcomes also differed among marsh plant species, and also differed as a function of spatial scale: the strength of competition in the transplant experiment was driven only by the presence or absence of mangroves in the immediate (3x3 m cell) vicinity of the transplanted plants, but natural colonization of 3x3 m cells within the 24 x 42 m plots was also a function of the cover of mangroves at the plot scale. Our findings suggest that manipulation experiments can give results that do not reflect patterns at the landscape scale if study sites are not representative of the landscape. Although global warming is likely to facilitate continued spread of mangroves, marsh plants are likely to persist on the landscape in areas where mangroves do not attain high cover.Item Marsh Explorer Game(2013-05) Vashisht, Sonal 1987-; Hilford, Victoria; Garbey, Marc; Pennings, Steven C.An ecosystem is a community of plants and animals, which interact with the environmental system for common resources like water, air, and soil. Several human-related activities or climatic changes affect these communities, which leads to stress in their natural habitat. The outcome of this stress is scarcity of necessary resources. As a result of this scarcity, the species in these communities compete with each other for their survival. The study of the growth behavior of these communities, through competition as well as reproduction, is the main objective of our project. Manually analyzing large amounts of spatially explicit data is very laborious and resource constraining. Thus, there is a need to develop a systematic way of collecting, parameterizing and validating spatially explicit data in the clonal plant community. Data acquisition was done for 3 years in Sapelo Island located in McIntosh County, Georgia, to retrieve information regarding marsh and dominant plants found in that area. Sapelo Island is the fourth largest barrier island in the State of Georgia, with an area of 16,500-acres. The sampling area was approximately 3,200 square meters. Images were captured for each square meter of this area for three consecutive years. These images are now being used for the Marsh Explorer game to gain information (count, location, etc.) of the plant and animal species in these images. The input of the game will be a series of images which contain spatially extensive digital information about clonal plant communities. The game will train the player by presenting him/her with an image for which we have preprocessed information. By displaying a preprocessed image, the aim is to see if the players are able to identify plants and animals correctly or not. A player will be awarded points when the player correctly identifies an animal or a plant from the image. After a player scores points above the threshold value, i.e., is trained, player will be presented with unprocessed images. The final output of this game will be an accurate description of the marsh, i.e., identification of plant and animal species together with their spatial locations.Item Predicting Insect Herbivore Distribution Using Climatic and Biotic Variables(2022-11-30) Adams, Tianjiao; Pennings, Steven C.; Frankino, W. Anthony; Crawford, Kerri M.; Prather, Chelse M.A central goal of community ecology is understanding species distribution in nature. The abundance of insect herbivores can vary greatly spatially and temporally. These variations can be explained by abiotic variables such as precipitation, they can also be explained by biotic variables such as nutrient availability. Here I present two field observational and two laboratory experimental studies to better understand factors and mechanisms affecting insect herbivore distribution in nature. I examined 1) the climatic and biotic factors influencing the spatial and temporal variation in the density of a dominant salt marsh katydid. I found that katydid density is highly dependent on land elevation, and the availability of plant biomass for both dietary and reproductive purposes. 2) the effect of precipitation on plant and orthopteran community composition and functional traits. I failed to find a generalized trend describing the relationship between spring precipitation and orthopteran community composition or functional traits. However, various Orthopteran species responded differently to spring precipitation even if they are in the same subfamily. This suggests there is no generalized trend for orthopteran species and merits studying individual species. I also examined 3) biotic factors that determine orthopteran dietary choices by quantifying functional traits in a feeding choice experiment. I also found no single generalized trend predicting the relationship between plant toughness and nitrogen and grasshopper mandibular traits or dietary preference. But I did find some trends on a subfamily and species level. Finally, I performed 4) a feeding experiment where I examined elevated dietary protein and sodium as a mechanism driving insect herbivore distribution in nature. And as expected, elevated protein and sodium improved offspring production and both nutrients worked synergistically to improve the earlier stages of growth.Item Response and Recovery of Low-Salinity Marsh Plant Communities to Constant and Pulsed Saline Intrusion(2017-05) Li, Fan 1987-; Pennings, Steven C.; Armitage, Anna R.; Cole, Blaine J.; Craft, Christopher Bruce; Frankino, W. AnthonyThe effects of climate change on environmental conditions will be manifested as both chronic changes and pulse changes of varying durations. In estuaries, future variation in sea level, freshwater withdrawal and drought will lead to saline intrusion into low-salinity tidal marshes. I sought to understand the responses to various salinization scenarios at individual, community and ecosystem levels. First, I used a mesocosm experiment to investigate the responses of individual low-salinity marsh macrophytes to different durations of saline water exposure, without interspecific interactions. Second, I used another mesocosm experiment to assess the response of plant communities to saline water pulses of three salinities for five durations, and then assessed subsequent community recovery when the saline pulses were withdrawn. Third, I used a field experiment to explore the impacts on a freshwater marsh plant community of short- and long-term changes in salinity. I ranked the freshwater marsh plant species in order from least to most salt tolerant as follows: L. peploides, P. hydropiperoides, P. cordata and Z. miliacea, followed by S. lancifolia and E. palustris in a tie. I found that community composition was increasingly affected by the more-saline and longer-duration treatments. In the second mesocosm experiment, most but not all of the plant species were able to recover from low-salinity, short-duration saline pulses in less than one year. Because not all the species recovered, post-disturbance community structure diverged among salinization treatments. In the field experiment, both presses and pulses of saline water addition caused the loss of L. repens, resulting in community composition diverging away from the controls. In the press treatment, plant biomass and diversity were strongly suppressed. In the pulse treatment, community composition did not recover to the baseline conditions in between pulses of saline water, as L. repens failed to fully recover from pulses of salinity. In the second mesocosm experiment, shifts in community composition prevented long-term reductions in productivity. In the field experiment, however, salt-tolerant plants could not immigrate, and salinity presses caused a significant decrease in aboveground biomass. In contrast, salinity pulses had no effect on plant production. These results show that species composition is more sensitive to environmental changes than overall ecosystem processes. However, changes in ecosystem structure due to pulse changes may not limit recovery in ecosystem function.Item Roots, Shoots, And Seeds, A Plant-Microbe Interaction Triptych: From Sea to Summit(2022-04-19) Luecke, Noah Carr; Crawford, Kerri M.; Pennings, Steven C.; Zufall, Rebecca A.; Callaway, RaganPlants interact with microorganisms on and within their roots, leaves and seeds, all of which can change the plant’s growth. These interactions have the potential to scale up and affect a plant’s role in a community and ecosystem. Traditionally, research has focused on the effects of microbes associated with specific plant parts, not considering the interactions between plant parts as the plant parts do in nature. We addressed this gap in research by evaluating the relative importance of each plant-part associated microbiome individually and in unison for plant growth and function. Using a combination of field surveys and greenhouse studies we looked at the diversity and effect of different microbiomes across a landscape. In an alpine environment we measured distribution and effect of seed microbes for multiple plant species. We also measured how soil microbes derived from communities varying in plant composition affected next generation plant species growth. We found seed microbes varied between species but not location and had no effect on germination. However, soil microbes from different origins affected plant growth differently, with soils that originated from low density and low richness plots demonstrating negative plant-soil feedback. Next, we tested the independent and interactive effects of three plant microbiomes on prairie plants varying in successional rank. We determined the combination of multiple microbiomes affected plant growth non-linearly and that the combination of all three microbiomes generated the best predictive model for plant successional rank. Then we tested the effects of soil and foliar microbes in combination on a community stabilizing mechanism, plant-soil feedback. We found that only with the addition of the foliar microbes, plant-soil feedback became significant, indicating soil microbes alone may not be sufficient for understanding community shaping processes. Lastly, we tested the effects of combining different sources of soil microbial inoculum to understand implications on restoration metrics in Gulf Coast dunes. We found that using multiple sources of microbial inoculum increased plant growth for one grass species, increased the abundance of soil stabilizing microbes, and promoted plant community evenness. Integrating multiple microbiomes in plants may better reflect each of their roles in nature.Item Scale-Dependent Interactions in Insect Food Web Modules(2017-12) Lin, Wei-Ting 1986-; Pennings, Steven C.; Wiernasz, Diane; Frankino, W. Anthony; Kilpatrick, Zachary P.; Armitage, Anna R.Species interactions likely produce scale-dependent patterns due to the dispersal of different species. Understanding the scale-dependency of species interaction is critical to the development of ecology theories, and is one necessary step toward better extrapolating experimental results to landscape-scale applications. I studied the scale-dependency of species interactions on food web modules based on a salt marsh plant (marsh elder, Iva frutescens). (1) I explored how predator-prey interactions between ladybeetles and aphids vary with spatial scale, using field population data, a field experiment and a spatially-explicit model. I found that both top-down and bottom-up effects were more striking at smaller scales. Using post hoc multi-scale analysis, I could confirm that the scale-dependency patterns found here were not caused by experimental artifacts. (2) I used enclosure experiment, field time-series data and a structural equation model based on two-month average population data to study side-to-side interactions between three herbivorous insects that all feed on Iva frutescens. From the field time series data, I found that many side-to-side interactions between herbivorous insects were only detected when observations were made with certain time scales. Theses delayed interactions cannot be found with experiment that focused on relatively short-term effects. Finally, (3) I studied the arthropod food web based on Iva frutescence at a much larger spatial scale and examined latitudinal autocorrelation patterns in the arthropod communities by analyzing field survey data. By comparing beta-diversity patterns of morpho-species with beta-diversity patterns of guilds, I concluded that geographic changes in community composition were best explained by changes in food web structure, rather than environmental filtering across the latitudinal gradient. In sum, my results suggest that observed patterns of species interactions vary a lot depending on the spatial and temporal scales at which observations are made, and the empirical approaches through which interactions were documented. My work illustrates that using multi-scale analysis and multiple methods to examining the same system allows discerning the effect of scale per se. These approaches would lead to deeper insights into the logical links between processes and patterns of species interactions.Item Scaling Up and Exploring Marsh (SUEM)(2015-12) Soni, Akshay A. 1990-; Hilford, Victoria; Garbey, Marc; Pennings, Steven C.; Tsekos, Nikolaos V.An ecosystem is a community of plants and animals. They support agricultural needs and provide clean air and water. However, recent environmental changes such as global warming and rising sea level caused a need to study these ecosystems. Ecological problems have the specificity of being dependent on biological elements with complex interactions. New tools are therefore needed to go past biological constraints and take into account the complexity of living ecosystems. Data acquisition was done for six years at Sapelo Island located in Georgia. The sampling area was approximately 3,200 square meters. Annually around 10,000 images were captured of a sampling area. Manually examining of a substantial amount of spatially explicit data is very laborious and resource consuming. The idea is to involve the general public in ecology projects, first train them in identifying species and then allowing them to identify these species. Thus, there was a need to develop a systematic way of accumulating, parameterizing and validating the volunteer’s contribution to these projects. Two ecology projects were developed as Web-based games. The first game, Scaling Up Marsh Science was developed to create a detailed mosaic of the sampling area by stitching multiple overlapping images. Applying automatic methods for image alignment and stitching did not produce precise results due to various factors such as perspective error, moving animals, amount of overlapping, shadows. The second game, Marsh Explorer was developed to get an exact description of the sampling area such as identification of the plants and animals species together with their locations. The final output of this game delivers a detailed summary of the sampling area. This thesis adds to the previous versions of these games basic gaming features such as player ranking, game levels, awards, guided training, player feedback system, administrative tools, image uploader, and database redesign. To date, approximately 400 volunteer players are contributing to these two projects.Item The Viability of Reusing Oilfield Produced Water for Agriculture(2018-05) Sappington, Emily Nicole; Rifai, Hanadi S.; Rodrigues, Debora F.; Louie, Stacey M.; Shaffer, Devin L.; Pennings, Steven C.; Burnett, DavidProduced water (PW), the largest volume byproduct of oil and gas production, is typically perceived as wastewater and is disposed of via injection wells. Emerging concerns regarding PW disposal have prompted renewed interest in potential beneficial reuse of this lower quality water. The reuse of PW for agricultural purposes was investigated in this dissertation. A major technology gap exists in the monitoring of PW quality. Confocal laser fluorescence microscopy (CLFM) was evaluated in this dissertation as an alternative to USEPA Standard Method 1664 for quantifying oil and grease (O&G) in PW. Quantification of O&G was studied in the presence of chemical and environmental parameters including salinity, particles, and chemical additives. Overall, the CLFM method produced rigorous results that can be improved using advanced image processing techniques. Results from a germination and plant growth study indicated that iron and clay cowpeas (ICC) germinated and grew when irrigated with diluted PW containing 4,000-10,000 mg/L salt. Promising effects on plant growth such as longer, heavier, and larger leaves were observed in plants watered using PW as compared to plants watered using salt water suggesting a potential long term benefit of using PW to irrigate crops. Results from a spatial analysis using indexing showed the greatest potential to reuse PW for agricultural purposes in the Permian basin. Based on the data available for the study, the Permian contained an abundance of cultivated cropland and oil and gas wells resulting in high supply/demand ratios based on available PW volume and need for irrigation water. The Permian basin also receives the lowest precipitation among all basins in Texas, indicating a greater potential for water stress in times of drought; thus, further supporting the need and value of alternative irrigation water sources.Item Using Adapted Native Communities to Manage Established Invasive Plants(2023-12) Clark, Glen; Crawford, Kerri M.; Pennings, Steven C.; Frankino, W. Anthony; Flory, S. LukeInvasive plants often benefit from a change in eco-evolutionary context, escaping herbivores, pathogens and competing plants from their home range. Introduced into naïve native communities, they can spread rapidly, threatening native plant diversity and ecosystem functioning. Increasingly, studies have shown that native species sometimes adapt in response to the selection pressures imposed by an invasive plant. Here, we explore the concept of using these adapted native species to accelerate the evolutionary response of invaded native communities. Our target species was the invasive forb Verbena brasiliensis, which was introduced to Gulf and mid-Atlantic coasts more than a century ago and since has spread throughout the South-Central United States. We hypothesized that the longer V. brasiliensis was present in an area, the greater the likelihood of adaptation by co-occurring native species. Through a series of greenhouse studies, we showed that competition with V. brasiliensis reduced the growth of a group of co-occurring plants by 18% to 86%. One of the mechanisms of the invasive plant’s dominance was its ability to leverage an increase in available nutrients into much faster growth. We identified several soil microbial communities that suppressed the invasive plant’s growth, but their effectiveness faded when introduced into background soils with existing microbial communities. Similarly, we found that while native plant species from some locations were able to compete more effectively with V. brasiliensis than others, when the species were assembled into small native communities, the advantage did not always persist. Finally, contrary to our expectations, the distribution of adapted native communities did not fit the chronosequence of the invasive plant’s spread that we constructed from herbarium data. Our results show how shifts in community context can prevent the benefits of adapted native species from being effective when transported to new locations. The issue not only presents a practical challenge to using adapted native communities in invasive species management, but it also suggests a reason why some invasive plants persist. While adapted native species may emerge in some locations, changes in community context may prevent them from spreading readily.