Current Research Projects by Department

Deficiencies of mineral elements in diets of humans are on the rise worldwide, even in the United States. These deficiencies limit the physical, intellectual, and mental health activities of the affected people. Poor or deterioration of soil fertility and the concomitant decline in agricultural productivity are major concerns in the World. Organic production of vegetables and fruits is growing, and it is important to assess if organic fertilization will sustain the quantity and nutritional values of foods grown from plants equally to the current practices of conventional farming. A current project in the Massachusetts Experiment Station studied organic and conventional fertilization of vegetable crops in relation to productivity and elemental nutrient composition for human nutrition. Biochar is charcoal produced from pyrolyzed biomass. Research suggests that biochar is a good amendment to enhance physical, chemical, and other agronomic qualities of soils. Amendments with biochar are reported to increase storage of carbon in soil, to increase fertility of soils, and to increase productivity and elemental nutrient composition of crops. The production of biochar from crop and other vegetative residues may be a strategy for management of organic waste. This project will investigate the benefits that might be obtained by use of biochar in enhancing yields and nutritional quality of vegetable crops. A review of literature has shown that additions of biochar to soils or growth media may improve plant nutrition through enhanced acquisition of nutrients by crops grown in biochar-amended media. Results have been variable and need some verification with further research.

In Massachusetts, several invasive insect species are either already affecting or pose a serious threat to the specialty crop industry. Stakeholders have voiced the need to address the most destructive invasive insects threatening their crops. In recent years, there has been interest in reduced-risk materials with insecticidal properties for the invasive pest spotted wing Drosophila (SWD), a vinegar fly that attacks berries and other soft-skinned fruits such as peach and cherry. Of particular interest are low-cost materials that could be used as attractants in traps or as insecticidal food-based baits, as opposed to broad-spectrum insecticides applied to the foliage against some pests. In this project, we will determine whether materials that are commonly available in households can be used to attract adult SWD to traps. Efforts will be made to develop an inexpensive insecticidal bait. The response of female codling moth and Oriental fruit moth, two important pests of apple, pear, and related crops, to lures that are based on plant material will be quantified under laboratory and field conditions. Our ultimate goal is to develop a food bait for SWD that is inexpensive and effective. This project also seeks to improve the effectiveness of monitoring systems for codling moth and Oriental fruit moth. If successful, results may lead to the development of more effective monitoring systems for these two moth pest species.

The project will employ established field and laboratory methods to measure litter decomposition, soil organic matter turnover, and nitrogen transformations. These methods could include isotope labeling and recovery, litter decomposition, quantifying soil organic matter, gross nitrification and nitrogen mineralization, potential net nitrification and net nitrogen mineralization, nitrous oxide production, carbon mineralization, and quantifying microbial biomass. These measurements are often collected from both field equipment and laboratory microcosms. The results are analyzed using a variety of tools. Generally, graphing tools are first used to examine trends in the data. The data will then be statistically analyzed using linear mixed models and, potentially, model selection. The statistical output is combined with graphic trends and site background information to interpret data and produce study outcomes. This study will incorporate formal education programs. The research project will be the basis from which to train a graduate student on methods in soil biogeochemistry and incorporation of applied research into graduate study. The field sites and methods will be incorporated into formal laboratory instruction for undergraduates. Involving undergraduates provides both inclusion in primary research and evidence of how research outcomes can be incorporated by farmers. 

This research, to be conducted at the University of Massachusetts, Amherst Crop and Animal Research and Education Farm in South Deerfield, MA.  In September of the first project year, white clover will be established. The effectiveness of four clover suppressing methods prior to corn planting will be investigated. Two full plot treatments, mowing and chemical control, and two in-row treatments, shank till (ST) and zone till (ZT), will be combined to form the four treatments: mowing + ST, mowing + ZT, chemical + ST, and chemical + ZT. The ST treatment, also called strip till, will create a 30 cm band to 5 cm depth while the ZT treatments will use a rotary implement to create a 40 cm band at 8 cm depth. The shallow tilling depths terminate the in row kura clover biomass without disrupting the larger soil structure. The plots with the mowing treatment will be mowed across the entirety of the plot the week before planting to suppress the clover biomass prior to planting. The mowing treatments will again be mowed between rows at mid-season to reduce clover height and prevent encroachment into the row. The chemical treatments will be sprayed as a broadcast application of glyphosate at the same time as the mowing treatments at a rate of 2.3 L ha-1. The chemical treatment will again be sprayed between rows mid-season to reduce clover height and prevent encroachment into the row. The day before planting, the tilling treatments will be applied to the planting row.

In the late spring of the first project year, we will delineate 16 main plots across the field of clover. Experimental plots are 24 m long × 2.4 m wide. The width of the plots allows for planting three rows of corn. Each plot will be randomly assigned a treatment (four treatments replicated four times). To test the N benefit of clover for corn production, the main plots will be divided into four subplots (6 m. long) for each of four nitrogen fertilizer treatments resulting in 64 total plots. The four nitrogen fertilizer treatments are 180 kg N/ha, 120 kg N/ha, 60 kg N/ha, and 0 kg. N. The fertilizer is applied in two stages: one-third of the application rate as starter fertilizer and two-thirds as side dressing when the corn is approximately 12” tall (V6 growth stage). The zero-fertilizer treatment allows us to measure both nitrogen use efficiency as well as the N benefit from only the clover. We will also establish a plot of conventionally grown silage corn (50 m. × 5 m.) adjacent to the treatment plots which will serve as a comparison for all above- and below-ground measurements under living mulch. In year 2, the 64 plots will receive the same treatment along the same timeline as year 1.

Measurements:

Plant: Clover biomass in November (for fall grazing) and Late April (spring grazing), corn yield and quality, and Late April (spring grazing), corn yield and quality, including RFV and Milk Value.

Soil: leaching, N residues, N2) and Co2 emission

The managed landscape is a complex and unique system, with a wide variety of plant and insect species comprised on a relatively small area. The maintenance and management approaches vary depending on the owner, and each property is a unique ecosystem with the unique complex of insect pests.

Managing insect pests in this complex system inherently has many challenges, but recently is exacerbated by the limited availability of pest management tools. Because of the high aesthetic standard and almost zero tolerance to any plant damage, the main management strategy preferred by practitioners is a chemical control. Additionally, recent regulations limit or ban of some of the already scarce tools. Some active ingredients are losing efficacy due to pest resistance to insecticides while use of others becomes restricted and/or pulled from the market. For example, organophosphate chlorpyrifos is no longer available for turfgrass use, and neonicotinoid use became restricted leaving many landscape managers searching for alternatives. At the same time recent demands on environmentally friendly, less toxic approaches to insect pest management are in high demand. One of the promising alternatives is biocontrol, or inundative use of nematodes, fungi, bacteria, and their metabolites, as an alternative to conventional chemicals. However, using living organisms are challenging and efficacy is greatly dependent on the application techniques, weather condition, and other factors. In addition, the biorational and biological methods cannot compete with the chemical control because of cost and lack of robust efficacy data. Practitioners are reluctant to invest in products with unknown efficacy.

Another challenge in the system has been brought by the changing weather patterns. The complexity of the species, their phenology and adaptation changes bring us to seek new information on how to manage the pest in the changing environment.

Sheep are valuable livestock species that have been raised for their production of meat, milk, fleece, and other by-products. More importantly, given their anatomic and physiologic similarities to humans, genetically modified sheep have become an important human disease model in pharmaceutical and biomedical research. Compared with somatic cell nuclear transfer and random transgenesis, CRISPR/Cas9-mediated genome editing is highly efficient and precise. However, due to the impaired developmental competence of embryos cultured in vitro, the overall success rate is still low when blastocyst embryos are transferred into the recipients. In this study, we propose to optimize the microenvironment of in vitro cultured sheep embryos by modulating the culture matrix stiffness, fluid flow, and embryo rolling, to improve the developmental competence of blastocysts, which stage allows for a much faster and less-painful non-surgical embryo transfer than the surgical procedure. Our proposed research, if successful, will innovatively streamline the production of genetically modified sheep and other large livestock animals, to increase both human and animal health and welfare.

We designed full-size field trials to test the effectiveness of sorghum-maize intercropping at the UMass Crop and Animal Research and Education Farm in South Deerfield, MA. Plots of sorghum monocrop and maize monocrop served as controls with two intercropping systems, alternating row and mixed seeding intercropping. All four planting treatments were coupled with DMPP application to compare the biological inhibition of sorghum to an artificial inhibitor. Nitrogen and potassium fertilizers were applied in a manner similar to local practices, with DMPP application occurring concurrently. Plants were grown throughout the summer and harvested in early October for the 2021 and 2022 growing seasons to represent a typical corn system in Massachusetts.

The methodology of this work relies primarily on the capture and analysis of N2O gas leaving the soil, which represents a loss of nitrogen from the system as well as a problematic source of greenhouse gas emissions. To capture this gas flux, we implemented static chambers placed over the soil for a period of 30 minutes and sampled gas from the chamber every 15 minutes. Gas samples were loaded into pre-evacuated glass vials and analyzed through gas chromatography. To ascertain the temporal variability of N2O flux, these measurements were carried out throughout the New England summer every 2 or 3 days. This sampling scheme is more intensive than those typically employed in the literature, with many studies measuring gas flux on a weekly basis or longer gaps. The high frequency of sampling events allowed us to better account for stochastic variables in the system such as soil moisture and temperature fluctuations as they changed throughout the season.

In addition to gas flux, we collected data on soil temperature and moisture, as well as detailed atmospheric data from a nearby weather station at the research farm. At the end of the growing season, we collected above ground biomass from representative areas of each plot to measure bulk yield for silage production, the intended production outcome for this experiment.

To further understand the underlying mechanisms of the reduction in N2O flux we periodically and destructively took bulk soil and root samples for microbial community analysis. In this analysis we compared the abundance of microbial communities responsible for nitrogen transformations in the soil, mainly ammonia-oxidizing bacteria and archaea as well as denitrifying bacteria. We will also be coupling these comparisons to more broad observations of the microbial community structure at high resolution to get insights into how the wider microbial community responds to N2O reduction treatments and intercropping systems.

The need to feed the ever-growing human population while decreasing greenhouse gas emissions from large-scale agriculture remains a global problem of paramount importance. One major source of these emissions is through nitrous oxide (N2O) production, a greenhouse gas with a warming potential nearly 300 times that of CO2. This potent greenhouse gas is formed through the action of soil microbes when they compete for artificial nitrogen fertilizer. While there are synthetic inhibitors that reduce N2O emissions, there can be many off-target effects. A promising alternative to these inhibitors is leveraging the natural ability of some plants to antagonize the microbial production of N2O, termed Biological Nitrification Inhibition (BNI). This ongoing research utilizes the BNI capacity of Sorghum bicolor, a staple grain crop in Africa and Southern Asia intercropped with corn (Zea mays). Plants were grown as monocrops or intercrops with alternating row and mixed seeding at the UMass Crop and Animal Research and Education Farm in South Deerfield, MA. These cropping treatments were repeated with an artificial nitrification inhibitor, DMPP, for comparison. Throughout the growth season, soil gas flux samples were collected via chambers covering the soil and analyzed through gas chromatography. Measured N2O concentrations over time were then converted to overall flux (production and consumption) to determine the reduction in N2O emissions. In addition to gas measurements, soil and roots were destructively sampled periodically throughout the growth season. Community analysis of the bulk soil and rhizosphere will reveal the microbial community’s response to the different cropping systems or the synthetic inhibitor treatment at high levels of resolution. At the end of the field season, plants were harvested to determine overall yield for all treatment groups. This experimental design has been repeated for a second year to account for seasonal variations in weather patterns. Throughout both years of the field trial, we found nearly 20% fewer N20 emissions in the sorghum monocrop plots as well as with mixed seed intercropping with the addition of DMPP, compared to the corn monocrop control. Total plant biomass production was not influenced by either treatment variation.

        The core hypothesis of this work is that the BNI capacity of sorghum will result in more nitrogen fertilizer available for both corn and sorghum when planted in close proximity, as well as reduced N2O emissions. The inhibitory chemicals secreted from the sorghum roots will affect the root zone of corn when planted in a way that both root systems overlap. This effect will lead to more plant-available nitrogen, lower N2O emissions, and higher silage yields for both corn and sorghum in intercropped systems. We expect this effect to be most pronounced in the mixed seeding plots as those plants are grown in the closest proximity. This work will determine the efficacy of intercropping corn, a plant with heavy nitrogen fertilizer needs with sorghum, a plant which has evolved ways to better compete with soil microbes for the available nitrogen applied as fertilizer, compared to the commercial inhibitor DMPP. To better understand the role of soil biological processes in controlling plant available nitrogen, a subsequent, complimentary experiment will be carried out this year to uncover the mechanism of action of the sorghum inhibition. These experiments together investigate a promising alternative to the current synthetic inhibitors in an effort to reduce greenhouse gas emissions in large-scale agriculture, while simultaneously reducing the amounts of artificial nitrogen fertilizer required to grow corn in today’s agriculture. Both resulting effects, the increased nitrogen fertilizer availability and reduced N2O production, will directly support the chosen objective, and widen our understanding of soil health and resilience. Resilience of this agricultural system is further supported by the documented drought resistance of sorghum, which will be needed with the expected longer drought periods in the currently changing climate. These changes will directly affect farmers who produce crops for silage.

Fusarium oxysporum species complex (FOSC) can cause vascular wilt on over 100 cultivated plant species (Ma et al., 2013; Michielse & Rep, 2009; Pietro et al., 2003). Because of its significance, F. oxysporum is listed among the top 10 fungal pathogens by the journal “Molecular Plant Pathology” (Dean et al., 2012). In the New England region, wilt diseases caused by Fusarium oxysporum are common agricultural problems that affect the production of vegetables, including asparagus, tomatoes, eggplant production, ornamentals, and variety of flowers (Elmer & Marra, 2011;https://www.prevalentfungi.org/). The widespread resistance to existing fungicides and the persistence of the thick-walled fungal chlamydospores in the soil heightens the difficulty in controlling the diseases and emphasizes the importance of appropriate control measures.

As an important group of crops, legumes are prized for their high protein content, which is thanks to their remarkable ability to make their own nitrogen nutrient through a symbiotic relationship with a particular group of bacteria. We still do not fully understand the legume genes that allow these plants, but not most others, to enter this nitrogen-fixing symbiosis. Evolution through millions of years has turned this relationship into a very elaborate process, requiring hundreds if not thousands of genes from both partners. To speed up the rate of scientific discovery, we developed a genetic method based on the CRISPR/Cas9 technology to examine genes suspected to be involved in this mutualistic interaction. This approach will allow us not only to study one gene at a time, but multiple genes at once if necessary. We will carry out the research on a small legume species easy to manipulate in the laboratory, but the findings will have important implications for important crops, such as soybeans, peas, and peanuts.

Pollination is critical for yield of many crops, but many pollinator species are in decline due to a variety of stressors including pathogens, pesticides, and insufficient food resources. Our work will ask how flowering plants and land use around farms affects the number of bee individuals and species at farms, and how effective bees are at pollinating sunflower crops. We will also determine how diet and floral resources affect bee health and ability to resist disease. Finally, many crops have seeds that are treated with pesticides to improve growth, but these pesticides can be incorporated into pollen and affect bees. We will ask how the amount of water a plant receives affects the concentration of pesticides in pollen, and the consequences for bees. Taken together, this work represents a comprehensive approach to understand some of the factors involved in pollinator decline.

Three obstacles that we address in this project are: (1) Even within a single crop species, not all plant genotypes respond the same way to PGP bacterial applications. This indicates the existence of a genetic basis to how plants respond to PGP bacteria that must be understood in order to successfully use PGP applications on different crop varieties. (2) PGP microbial applications are extremely susceptible to microenvironmental variation; thus, achieving sufficiently uniform conditions, to test the effectiveness of an application poses a challenge. (3) PGP effects are often likely mediated through impacts on plant roots, but belowground responses to PGP-bacteria have traditionally been difficult to assess.

            We have been developing the grass model species, Brachypodium distachyon, as an ideal plant system for screening and evaluation of PGP bacteria. As a species that is easily and rapidly grown in a laboratory setting and is closely related to wheat, rye, oats, barley, and several forage grasses, B. distachyon offers a screening system that is likely to ensure translation of findings to relevant crops. We have also developed a novel standardized growth system, termed “rhizotrons” to study the effect of PGP bacteria on above- and belowground plant phenotypes under high-throughput conditions. With these systems we have the following objectives:

Objective 1: Develop protocols and quantify the effects of a known PGP bacteria on belowground plant growth in a line of B. distachyon that allows for real time quantification of root architecture.

Objective 2: Assess the differential effect of this PGP bacteria on above-ground growth of several lines of B. distachyon that have been used.

Objective 3: Used a controlled cross of B. distachyon lines that differ in response to PGP application to identify genes controlling this response.

            Our target audience is basic plant researchers seeking to understand mechanisms of pant growth and those seeking to create more sustainable crops. Our activities will lead to the outcomes described above through creation of protocols to quantify root growth, identification of B. distachyon lines that respond in a differential manner to PGP bacteria application, identification of plant growth traits that are more and less likely to be impacted by PGP microbes, and identification of candidate loci for plant genotype x PGP microbe response in B. distachyon. This will benefit our target audiences by providing research tools and knowledge that can be leveed for further gene discovery and by helping accelerate the discovery of similar genes in energy, cereal, and forage crops and ensuring translation of our findings to agriculture.

We will collaborate with various companies that are developing OMRI approved products (Coppers, Beneficial Microbes/Biocontrol agents and systemic resistance inducers) and identify compounds with proven efficacy in other cropping systems. Identified compounds will be integrated with registered Group 3 & 11 fungicides and will be evaluated for their efficacy in managing cranberry fruit rot and enhancing fruit quality (fruit color as evaluated by total anthocyanin content, fruit firmness and fruit size as evaluated by fruit weight). The proposed novel treatments will be evaluated in comparison with traditional grower standards (all chemicals) and non-sprayed controls. The study will be conducted on State bog at UMass Cranberry Station, East Wareham. All the treatments will be replicated five times in 4 x 4 ft (1.2 x 1.2 m) plots. All the local recommended fertilization, irrigation and pest management practices will be followed. Fungicides/novel compounds in each treatment will be applied at designated phenological stages using a CO2 powered backpack sprayer. In late September, from each replicated plot, all fruit from within an arbitrarily selected 1 foot-square area will be harvested by hand. Yield data will be obtained by converting the weight of the berries from 1 foot-square area to barrels/acre. Berries will be evaluated for fruit rot incidence (number of rotten berries/total number of berries x 100). An additional 500-gram subsample from each replicated plot will be used for fruit size and fruit color evaluation. Fruit firmness will be evaluated for samples of 50 healthy berries from each plot.

Widespread, international and local interest in greening municipalities and increasing urban tree canopy cover continues, largely through community-based tree planting initiatives. It is generally estimated that newly-installed (i.e., planted) trees require at least 3 or more years before establishment, when they resume pre-transplant growth rates. Most trees installed in the urban environment are dug from the nursery field with a spade and wrapped in burlap and a metal basket (‘B&B’ or ‘balled and burlap’ or ‘BnB’). There is interest, however, by tree enthusiasts (i.e., shade tree committee members, Master Gardeners, etc.) and professional urban foresters (i.e., tree wardens/municipal foresters), in planting trees grown using other easier-to-plant systems, including a variety of container-grown (CG, IGF) and bare-root (BR) tree production methods. Ideally, trees that are being planted persist longer than the individuals that are installing them, thus trees grown from these production systems, must have the potential to grow long-term and reach maturity to provide optimal value in relation to the social, economic, and environmental services that urban trees are known for. This may be a challenge, since urban environments often present very difficult growing conditions that foster widespread urban tree morbidity and premature mortality. Though advances in understanding have been made, there is a dearth of empirical data describing the survival and growth of these trees, with the preponderance of research considering trees growing in traditionally forested environments or agricultural plots, rather than urban settings. Since budget constraints are routinely identified as a key limiting factor relative to urban forest management practices, there is also a need for further information concerning the longer-term costs associated with maintaining newly-installed urban trees.

Collecting growth and maintenance cost data on established urban oak specimens in Amherst, MA, produced using various nursery systems will 1) add to the overall base of knowledge concerning urban tree growth and survival 2) enable the quantification and further understanding of the relationship of urban tree growth/survival and nursery production system 3) Enable the quantification and further understanding of the long-term costs associated with planting and maintaining urban trees. The long-term goal of this work is to gather local, empirical data that will help urban forest practitioners consider the appropriate (i.e., most cost-effective, best-performing) nursery production system, when selecting trees for urban planting in Massachusetts and other New England communities.

Regeneration is the future of Massachusetts forests. It is critical for the conservation of the State's forestlands and for the continued provisioning of the myriad ecosystem services they provide (sustainable timber and wood products, carbon storage,wildlife habitat, clean drinking water, biodiversity, recreational opportunity, and aesthetic/intrinsic value). Global change related factors including novel climatic conditions, invasive plants, deer overpopulation, and habitat fragmentation threaten current and future forest regeneration within Massachusetts. These threats come at a critical time when we are already observing increased mortality of economically and ecologically important tree species across the State at the hands of non-native pests and pathogens. Ensuring successful regeneration of desired tree species and natural communities within these damaged forests is paramount to the continued health, vigor, and viability of the State's forest resources.Adaptive forest management may be used to overcome contemporary regeneration challenges, ensuring the conservation of healthy and valuable forest ecosystems. However, we currently lack sufficient regeneration data and scientific understanding of the various factors impacting regeneration to develop and test meaningful adaptive management strategies.

Forest dynamics and the spatial and temporal modeling of the dynamics of Food-Energy-Water (FEW) systems at a watershed scale are critical for sustainable land and resource management. The assessment of vegetation (Forest and plant biomass) and land use dynamics is vital for scientific innovation and for enhancing local and regional sustainability and resilience. Assessing built, natural, and social components and their interactions as a dynamic system can lead to comprehensive strategies that improve food production, conservation, energy efficiency, and water resources. Dynamic changes in FEW systems are complex processes, especially the state of the complex system and its trajectory over time. As the population increases and new demands on ecosystem services, watersheds face environmental, energy, and food challenges. This could include polluted waterways, floods, droughts, loss of forest and green space, energy inefficiencies, crop loss, yield loss, soil erosion, increasing density of built structures, and a deterioration in watershed services. Increasing population densities increase built components causing higher forest loss, impervious cover, wastewater discharges, stormwater surges, nonpoint source pollution, loss of open space, farmland loss, and habitat fragmentation that substantially impact watershed systems. Agricultural land is also at increasing risk from urbanization with pressure to produce more in a limited area and with limited resources.

The nexus between food, energy, and water (FEW) has strong interaction with land use-based assessment, requiring system-based modeling for policy. The system information on interactions, tradeoffs, trajectories, thresholds, and endpoints in FEW systems is needed to evaluate sustainable patterns and processes that can be used to manage built, natural, socioeconomic, and cyber systems. We propose to study these issues at a regional watershed scale through integrated spatial and temporal modeling of forest dynamics at a watershed scale. 

The goal of this research is to simulate and optimize interactions in patterns and processes in built, natural, and socioeconomic components and forest dynamics on FEW services based on a multiscale system at the watershed scale. Specifically, (i) to evaluate baseline spatial and temporal changes in FEW systems at the watershed scale; (ii) To assess the influence of changing built and natural environment on FEW dynamics and processes; (iii) to evaluate farmland management and its impacts on FEW systems; (iv) to study attitude, values, and behavior towards FEW outcomes under land-use patterns and conservation alternatives; (v) to develop a multiattribute, optimization model for pattern and BMP choice to enhance watershed sustainability for FEW provision; (vi) to develop a web-based decision support system (WDSS) with site-specific information for stakeholders on FEW resilience and conservation choices.

The target audience will include farmers, land owners, municipal officials, private forest owners, government agents, nonprofits, educators, scientists, and professionals. The information generated will cover the watershed-based assessment, strategies to sustain water resources through forest management, handling increasing urban demands through forest BMPs, supply augmentation potential through forest ecosystem functions, and potential effects of LID at the watershed scale. Educators can use the information to develop simple classroom activities demonstrating workshop concepts. 

Research activities in the Connecticut River Watershed with result in outcomes that directly benefit the target audience through capacity building and spatial information that will be helpful for decision-making. The workshops will provide information on the spatial distribution of water supplies and use and trends in distribution. The workshop will recommend strategies to sustain water resources and will involve brainstorming and breakout sessions to develop implementation plans. A website will be developed for the project and will be used to disseminate information to communities within the watershed and watersheds throughout the region and the US

A pressing problem for forest managers and society as a whole is the need to mitigate rapid environmental changes affecting allof life on earth. Third to only to habitat destruction and direct exploitation, biological invasions are a leading cause of extinctionand loss of biodiversity in forest ecosystems and around the world (Dirzo and Raven 2003). One poorly understood aspect ofbiological invasions is that the introduction of non-native organisms to areas outside their home range leads to novel ecologicalinteractions among species that have not historically co-existed. These new interactions raise key theoretical questions, suchas: How do species adapt to new environments as they expand their range? Can novel species interactions alter longstandinginteractions between native species? Do native species re-assemble into new food-webs with novel suites of species afterinvasion? We will address these questions in terms of invasive plants and their effects on native species of New England'sforest ecosystems.