Invasive plants are expanding their ranges due to climate change, creating new challenges for invasive species management. Early detection and rapid response could address some nascent invasions, but limited resources make it impossible to monitor for every range-shifting species. Here, we aimed to create a more focused watch list by evaluating the impacts of 87 plant species projected to shift into northern New England (the states of Maine, New Hampshire, and/or Vermont). We used the Environmental Impact Classification for Alien Taxa (EICAT) protocol to evaluate all ecological impacts reported in the scientific literature, scoring ecological impacts from 1 (minimal concern) to 4 (major) depending on the level of reported impact. For each species, we also recorded any reported impacts on socioeconomic systems (agriculture, human health, or economics) as “present.” We found 24 range-shifting species with impacts on ecological communities, of which 22 have reported impacts in ecosystems common to northern New England. Almost all of these species also had impacts on socioeconomic systems and were available for purchase at ornamental plant retailers or online. Thus, these species can be considered high risk to northern New England with climate change based on their large negative impacts and potential to arrive quickly with deliberate human introduction. Our study demonstrates the use of impact assessments for creating targeted priority lists for invasive species monitoring and management.

Meadow hawkweed is an invasive, perennial forb of upland forest openings, mountain meadows, permanent pastures, and abandoned farmlands in the Pacific Northwest. The objective of this study was to measure the plant community response, following meadow hawkweed control using selective herbicides and a single application of N–P–K fertilizer, across three levels of meadow hawkweed infestation in cleared forestlands that had been converted to pasture in northern Idaho. Clopyralid was applied to meadow hawkweed rosettes at a rate of 0.59l kg ae ha−1 (0.528 lb ac−1), and fertilizer (23–5–5, 1% Fe, 14% S) was broadcast following herbicide applications at two rates, 44 and 88 kg N ha−1. Foliar cover of meadow hawkweed, Idaho fescue, and other perennial grasses was measured in microplots at three levels of initial meadow hawkweed cover; < 25%, 40 to 60%, and > 75%. Clopyralid treatments resulted in excellent meadow hawkweed control 3 mo after treatment (MAT). Clopyralid alone appeared to shift the competitive balance in favor of perennial grasses, which increased 7, 44, and 65% above pretreatment levels in LOW, MED, and HIGH hawkweed cover plots, respectively, across fertilizer treatments. Meadow hawkweed cover remained < 5% in clopyralid plots at 52 MAT. Fertilizer effects were confined to interactions between Idaho fescue and other perennial grasses.

Cogongrass [Imperata cylindrica (L.) Beauv.] is a warm-season, rhizomatous grass native to southeast Asia that has invaded thousands of hectares in the southeastern United States. Its negative impacts on pine forests have been well documented, and aggressive control is widely recommended. Although repeated herbicide treatments are effective for suppression, integrated strategies of prescribed burning coupled with herbicide treatment and revegetation are lacking in pine systems. In particular, longleaf pine forests, which are typically open, fire-dependent, communities, are highly susceptible to cogongrass, which is a pyrogenic species. To address management goals for cogongrass control and herbaceous restoration in longleaf pine forests better, field studies were conducted in southwestern Alabama from 2010 to 2012. Two longleaf pine forests with near-monotypic stands of cogongrass in the understory were selected for study. Treatments included combinations of winter prescribed fire, spring and fall glyphosate herbicide treatments, and seeding a mix of native, herbaceous species. Data were collected for three growing seasons following study initiation, and included seasonal herbaceous species cover and final cogongrass shoot and rhizome biomass. Species richness and diversity were calculated and analyzed to ascertain treatment effects over the duration of the study. Burning slightly improved cogongrass control with glyphosate, but had no effect on total cover, species richness, or species diversity. Three glyphosate treatments reduced total vegetative cover and nearly eliminated cogongrass cover, shoot, and rhizome biomass. Glyphosate and glyphosate + seeding also increased herbaceous species richness and diversity. However, aboveground productivity in treated plots was significantly lower than productivity in the untreated control, which was almost exclusively cogongrass. These studies indicate that glyphosate and integrated strategies utilizing glyphosate and seeding are very useful for cogongrass management and increasing herbaceous species richness and diversity in longleaf pine.

Few individuals or governments have suggested that invasions by nonindigenous species are relevant to the broader issue of human security, despite a growing awareness of the ecological, economic, and societal impacts associated with invasive nonindigenous species (INIS). We propose that by framing management actions in a human and environmental security context, the threats (and benefits) posed by INIS to individuals and communities can be explicitly articulated and debated. This framework allows multiple stakeholders to bring their concerns to bear upon specific policy, and attempts to integrate broad environmental concerns within its parameters. We use the case of ecosystem-based management of invasive nonindigenous plants as an example of the utility of a human security framework. The dominant management approach to these species remains focused on the individual species, despite increasing calls for the implementation of ecosystem-based management strategies. Ecosystem-based management is supported by generalized and widely accepted mechanisms of plant community dynamics, such as succession, disturbance, and interspecific competition, but these scientific arguments do not consistently carry weight at the policy level and with the broader public. A human security framework may provide an approach for overcoming this resistance by placing the debate over management within the social and political context of the wider community. Overall, human security can allow applied ecologists to be better positioned to meet the challenges of communicating the need for science-based management.

Pale swallowwort and black swallowwort are European viny milkweeds that have become invasive in many habitats in the northeastern United States and southeastern Canada. A multiyear seedbank study was initiated in fall 2011 to assess annual emergence of seedlings and longevity of seeds of pale swallowwort and black swallowwort at four different burial depths (0, 1, 5, and 10 cm) over 4 yr. One hundred swallowwort seeds were sown in seed pans buried in individual pots, and emerged seedlings were counted and removed from May through September each year. A subset of seed pans was retrieved annually in October, and recovered seeds were counted and tested for viability. The majority of seedling emergence occurred during the first year (92% in 2012), and no new seedlings emerged in the third (2014) or fourth (2015) years. Pale swallowwort had relatively poor emergence at sowing depths of 0 cm (11%), 5 cm (6%), and 10 cm (0.05%—only one seedling), while 37% of pale swallowwort seeds emerged at 1 cm. The larger-seeded black swallowwort was more successful, with two-thirds of all sown seeds emerging at depths of 1 cm (71%) and 5 cm (66%), and 26% emerging at 10 cm. Only 16% of the surface-sown black swallowwort emerged. A large portion of the seeds that germinated at 10 cm, as well as at 5 cm for pale swallowwort, died before reaching the soil surface. Of filled seeds that were recovered in 2012 (black swallowwort at the 0-cm depth), 66% were viable. No viable seeds were recovered after the second growing season. Seeds recovered following the third year had become too deteriorated to accurately assess. Swallowwort seeds do not appear to survive more than 2 yr in the soil, at least in our experiment, suggesting that the elimination of seed production over 3 yr will exhaust the local seedbank. Seeds would need to be buried at least 10 cm for pale swallowwort but more than 10 cm for black swallowwort to prevent seedling emergence. Burial of swallowwort seeds as a management strategy may, however, only be practical in natural areas where high swallowwort densities occur.

Yellow starthistle (Centaurea solstitialis) is among the most invasive plant species in the western United States. The long-term management of yellow starthistle should include an integrated approach that incorporates establishment of competitive vegetation. In this study, conducted in two locations at Fort Hunter Liggett in Monterey County, California, we evaluated the combination of prescribed burning, the herbicide aminopyralid, and reseeding of native broadleaf and grass species on both yellow starthistle control and native plant restoration. Both study sites were burned in late October 2009. Over the following season, aminopyralid was applied at three timings and native plant species were seeded at three timings, using both a drill-seeder and broadcast spreader. Evaluations over the next 3 yr showed that aminopyralid provided complete to nearly complete control of yellow starthistle when applied between January and March, and this level of control was maintained for two seasons. Native plants failed to establish when broadcast seeded, regardless of the timing. December and January drill seeding timings were the most successful in establishing native species. There was a strong herbicide and drill seed timing interaction effect on native grass cover at both study sites. Over the course of the study the native perennial grass Stipa cernua was the most successful seeded species to establish, but establishment was slow and required 3 yr. Our results indicate that a January or March aminopyralid treatment integrated with a native perennial grass drill seeding program in January offers the greatest probability of both successful yellow starthistle control and perennial grass establishment.

Ventenata [Ventenata dubia (Leers) Cross] is a winter annual grass relatively new to the inland Pacific Northwest that is capable of displacing desired vegetation. Indaziflam was evaluated for the management of V. dubia on two Conservation Reserve Program (CRP) sites near Moscow, ID, and Pullman, WA. While perennial grasses were dormant, applications of indaziflam in mixture with various herbicides were made in spring 2016. Treatment effects were evaluated for 2 yr by visual assessments of community composition and canopy cover of V. dubia and other non-weedy species (assessments occurred 3 to 6 mo after treatment, depending on location) and by representative cover class assessments. Biomass samples of all plant species were collected in the summer of 2017. Reduced V. dubia cover was observed in 2016, except when glyphosate was used alone. In 2017 indaziflam applied alone or in mixture with rimsulfuron effectively controlled V. dubia with minimal impact on desirable vegetation. Plant biomass from nontreated plots averaged 40 g m−2 for V. dubia and 100 to 179 g m−2 for perennial grasses. Plant biomass averaged <11 g m−2 for V. dubia and 371 to 490 g m−2 for perennial grasses when indaziflam at 102 g ai ha−1 plus glyphosate at 474 g ai ha−1 was applied. Smooth brome (Bromus inermis Leyss.) biomass was positively associated with the reduction of V. dubia, and there was a decrease in diversity associated with the removal of V. dubia through effective treatments. Indaziflam is an effective tool for the management of V. dubia in perennial grass stands, and spring applications of indaziflam should be in mixture with herbicides with POST activity.

Predicting site vulnerability to nonnative plant establishment remains a difficult goal. Seedling survival is an important component of population dynamics and can affect the success of control strategies. Field manipulations allow potential causal mechanisms of site vulnerability to be evaluated under realistic environmental conditions. We conducted field studies to determine the effects of plant competition and differing precipitation regimes on spotted knapweed seedling survival. We also examined the effect of herbivory on rosette survival and growth. Seeds were sown into plots with vegetation intact or removed at three sites. Seeds were also sown into plots where plant competition and precipitation were manipulated in a factorial design at a single site. Field studies demonstrated that site accounted for much of the variation in emergence rate, while herbivory and plant competition affected seedling survival rates. We observed a wide range in emergence rates, with site averages ranging from 13.1 to 42.5%. Survival the following year ranged from 0.5 to 9.4% of sown seeds. Rosette survival was significantly higher when herbivores were excluded from plots. Below average precipitation reduced seedling survival; however, even with supplemental water, dry-down of exposed sites resulted in low seedling survival. Of the 8,000 seeds added to plots in one study, by autumn, only eight plants resulted, seven of which survived in watered plots with intact vegetation. Collectively, these results show that seedling survival is a critical phase in spotted knapweed population dynamics and can vary among habitats on the basis of plant competition and precipitation. Furthermore, herbivory affects all stages of the lifecycle from the seedling onward. The observed differences help explain the reported variability in seedling survival in the literature and inform efforts to control spotted knapweed using plant competition and biological controls.

Old World climbing fern (OWCF) is a highly invasive fern that disrupts natural communities in central and southern Florida. OCWF produces copious, wind-blown spores that have propelled its rapid invasion of Florida's natural areas over the last few decades. Current management of OWCF is limited to herbicides and natural resource managers in Florida have questioned if herbicides inhibit spore germination. This study compared spore germination rates of OWCF exposed to six herbicides and a surfactant from 1 to 24 h under laboratory conditions. Spores of OWCF were highly susceptible to metsulfuron, but exhibited tolerance to imazapyr, glyphosate, fluroxypyr, asulam, and triclopyr. Spore germination rates were 0.4% for spores exposed to 0.1 g ai L−1 of metsulfuron, but 0% for rates greater than or equal to 0.2 g ai L−1 at 30 d after treatment (DAT). Reduction in spore germination was observed with all other concentrations of herbicides tested, ranging from 10.4% with triclopyr (40 g ai L−1) to 42.6% with asulam (4.2 g ai L−1) compared to 47.9% germination for untreated checks 30 DAT. Spores were highly sensitive to metsulfuron with herbicide concentrations required for 50 and 95% inhibition of spore germination (I50 and I95) measuring 0.014 and 0.063 g ai L−1, respectively; spores were greater than 1,000-fold more sensitive to metsulfuron compared to I95 concentrations of any other herbicide tested. These results indicate that metsulfuron exhibits potential to control OWCF spore germination but spores are tolerant to the five other herbicides tested.

This study evaluated the effectiveness of 14 herbicide treatments for purple loosestrife (Lythrum salicaria L.) control over a period of 10 yr. The study commenced in 2000/2001 at four wetland locations in Nebraska. The evaluated herbicides included: glyphosate at 2.2 and 3.4 kg ha−1; 2,4-D dimethylamine at 1.4 and 2.8 kg ae ha−1; triclopyr at 1.3 and 2.1 kg ae ha−1; imazapyr at 1.1 and 1.7 kg ae ha−1; metsulfuron at 0.042 and 0.084 ai kg ha−1; fosamine at 13.5 and 22.4 kg ai ha−1; triclopyr at 1.3 kg ae ha−1 plus 2,4-D amine at 1.4 ae kg ha−1; and metsulfuron at 0.042 kg ai ha−1 plus 2,4-D amine at 1.4 kg ae ha−1. Some treatments provided excellent control (90%) that lasted only one season, while others suppressed L. salicaria growth for multiple seasons, depending on the location and the age of L. salicaria stand. Application of higher rates of glyphosate, imazapyr, and metsulfuron consistently provided excellent control (≥90%) of L. salicaria that lasted 360 d after treatment at most locations. Application of fosamine and the lower rate of 2,4-D amine provided the least L. salicaria control at most locations. The older the L. salicaria stand, the more multiple applications of herbicides were needed to completely control L. salicaria. Generally, there were higher percentages of grasses in the 2,4-D-, triclopyr-, and metsulfuron-treated plots compared with higher percentages of broadleaf species in the glyphosate- and imazapyr-treated plots at each location.

Using species distribution models (SDMs), we predicted the distribution of 170 plant species under different climatic scenarios (current and future climatic conditions) and used this information to create invasion risk maps to identify potential invasion hot spots in California. The risk of invasion by individual species was also assessed using species’ predicted area in combination with some biological traits associated with invasiveness (growth form, reproduction mechanisms, and age of maturity). A higher number of species would find suitable climatic conditions along the coast; the Central Western (CW) and South Western (SW) were ecoregions where a higher number of species were predicted. Overall, hot spots of species distribution were similar under current and future climatic conditions; however, individual species’ predicted area (increase or decrease) was variable depending on the climate change scenario and the greenhouse gas emission. Out of the 170 species assessed, 22% ranked as high-risk species, with herbs, grasses, and vines accounting for 78% within this risk class, and a high proportion (67%) of Asteraceae species ranked as high risk. This study suggests that current climatic conditions of the central and south coastal regions of California would be considered as hot spots of new invasions, and for some species this risk might increase with hotter and drier future climatic conditions.

Although an increasing number of investigations have been made into the evolution of alien species once introduced, few studies have identified the invasion routes of these introduced species. Because multiple introductions are common in invasive species, failing to take into account the introduced lineages can be misleading when studying evolutionary change in alien species after they begin to extend their ranges. In Japan, diverse lineages of ryegrasses (Lolium spp.) were introduced as forage crops and contaminants in trading grain and have expanded to sandy coasts. We studied the expansion route of populations established along the coasts of three geographic regions within Japan by comparing variations in morphology and nuclear microsatellite and chloroplast DNA in the two habitats where ryegrasses were first introduced: croplands and international seaports. Chloroplast DNA haplotypes did not differ significantly among habitats and regions, but the coastal and seaport populations displayed similar microsatellite genetic compositions and morphological characteristics. Our results revealed that coastal populations originated from seaport populations derived from contaminants. Selective forces from the past, including domestication and naturalization, may have assisted the introduced lineages in colonizing new habitats.

Estimates of plant biomass are helpful for many applications in invasive plant science and management, but measuring biomass can be time-consuming, costly, or impractical if destructive sampling is inappropriate. The objective of this study was to assess feasibility of developing regression equations using a fast, nondestructive measure (cover) to estimate aboveground biomass for red brome (Bromus rubens L.), a widespread nonnative annual grass in the Mojave Desert, USA. At three study sites, including one measured for three consecutive years, B. rubens cover spanned 0.1% to 85% and aboveground biomass 1 to 321 g m−2. In log10-transformed linear regressions, B. rubens cover accounted for 68% to 96% of the variance in B. rubens biomass among sites, with all coefficients of determination significant at P < 0.05. For every doubling of percent cover, biomass was predicted to increase by 78%, 83%, and 144% among the three sites. At the site measured for three consecutive years, which ranged in rainfall from 65% to 159% of the long-term average, regression slopes each year differed from other years. Regression results among sites were insensitive to using cover classes (10 classes encompassing 0% to 100% cover) compared with simulated random distribution of integer cover within classes. Biomass of B. rubens was amenable to estimation in the field using cover, and such estimates may have applications for modeling invasive annual plant fuel loads and ecosystem carbon storage.

Energy-extraction disturbances entail soil handling and often have large edge-to-area ratios. These characteristics should be considered when designing weed-control strategies. In western North America, many energy developments coincide with infestations of downy brome, an annual grass that severely curtails productivity, diversity, and habitat value of invaded areas. Downy brome is sensitive to soil compaction and seed burial, both of which may occur when soil is handled. In this study, I examined the effect of soil-density manipulations and herbicide application (105 g ai ha−1 imazapic with 280 g ai ha−1 glyphosate) on six simulated pipeline disturbances in a Wyoming big sagebrush ecosystem invaded by downy brome. Disturbances occurred at the end of the growing season, after ambient downy brome seed rain in the study areas had abated. Treatments and seeding occurred shortly after disturbances. The following spring, downy brome seedling density was 10-fold lower within disturbances than in control areas, but seedling density quickly rebounded in disturbed areas where no herbicide had been applied. In herbicide plots, downy brome seedling density remained low during the first growing season, and shrub cover after 3 yr was eight times higher than in no-herbicide plots. Soil density manipulations via disking and rolling treatments had little effect on downy brome. Prior research has shown that imazapic is more effective when combined with disturbances, such as fire. This study demonstrates that imazapic may also be effective in combination with a disturbance that is timed to bury downy brome seeds.

Mexican sunflower [Tithonia diversifolia (Hemsl.) A. Gray] is an invasive plant, native to the New World, and an exemplary conflict species. It has been planted widely for its ornamental and soil fertility enhancement qualities and has become a notorious environmental weed in introduced habitats. Here we use a bioclimatic niche model (CLIMEX) to estimate the potential global distribution of this invasive plant under historical climatic conditions. We apply a future climate scenario to the model to assess the sensitivity of the modeled potential geographic range to expected climate changes to 2050. Under current climatic conditions, there is potential for substantial range expansion into southern Europe with moderate climate suitability, and in southern China with highly suitable climates. Under the near-term future climate scenario, there is potential for poleward range expansion in the order of 200 to 500 km. In the tropics, climatic conditions are likely to become less favorable due to the increasing frequency of supra-optimal temperatures. In areas experiencing Mediterranean or warm temperate climates, the suitability for T. diversifolia appears set to increase as temperatures warm. There are vast areas in North America, Europe, and Asia (particularly China and India) that can support ephemeral populations of T. diversifolia. One means of enjoying the aesthetic benefits of T. diversifolia in gardens while avoiding the unwanted environmental impacts where it invades is to prevent its spread into areas climatically suitable for establishment and only allow it to be propagated in areas where it cannot persist naturally.

Restoration of abandoned agricultural lands to create resilient ecosystems in arid and semi-arid ecosystems typically requires seeding or transplanting native species, improving plant–soil–water relations, and controlling invasive species. We asked if improving water relations via irrigation or surface mulch would result in negative tradeoffs between native species establishment and invasive species competition. We examined the effects of sprinkler irrigation and straw mulch on native seed mixtures planted in two consecutive years in an abandoned agricultural field in a cold desert shrubland in southwestern Nevada, USA. Restoration effects differed among years because of contingency effects of growing season conditions. Precipitation was low during the first year and seeded plant density and biomass increased in response to irrigation. Precipitation was relatively high during the second year, seeded plant densities and biomass were generally high, and irrigation had inconsistent effects. Mulch increased native plant cover in the absence of irrigation during the dry year. Invasive plant biomass and cover also were influenced by year, but irrigation increased invasive plants regardless of precipitation. Positive effects of irrigation on seeded plant density, cover, and biomass outweighed negative tradeoffs of increases in invasive plants. In ecosystems with highly variable precipitation, the most effective restoration strategies will most likely be adaptive ones, requiring determination of timing and amount of irrigation based on precipitation, native plant establishment, and invasive species composition and abundance.

White sweetclover and narrowleaf hawksbeard are nonindigenous invasive plant species in Alaska that are rapidly spreading, including into areas that are otherwise free of nonindigenous plants. There has been concern that native moose could be dispersing germinable seed from these plants after ingestion. To address this concern, a study was conducted involving tame moose at the University of Alaska Fairbanks Agriculture and Forestry Experiment Station, Matanuska Experiment Farm, Palmer, AK. Objectives were to determine if seeds from these two plant species could survive mastication and digestive passage through moose, whether this passage impacted seed germination, and whether seed passage rates were the same as similar sized Cr-mordanted fiber. In this study, narrowleaf hawksbeard seed rarely survived mastication and digestion with only five seedlings recovered from 42,000 germinable seed fed to the moose. About 16% of germinable white sweetclover seed (3,595 of 22,000) fed to the moose produced seedlings. Most of the sweetclover seedlings came from feces produced 2 and 3 d after feeding. In two moose, sweetclover seedlings were grown from fecal material that was passed 11 d after feeding, raising the possibility that seeds could be transported long distances after ingestion. Cr-mordanted fiber passage did not closely follow seedling producing seed, possibly because time in the rumen might reduce seed germination. Once roadsides in Alaska become infested with white sweetclover, moose can then serve as a transport vector of these weeds into river channels and floodplains, which are distant from roads. This information will impact white sweetclover management programs and alert land managers to the potential for other instances of wildlife-mediated seed dispersal.

Miscanthus × giganteus, a widely planted biofeedstock, is generally regarded as a relatively low invasion concern. As a seed-infertile species, it lacks a consistent mechanism of long-distance dispersal, a key contributor to invasion rate, and constitutes a low risk for cultivation escape. However, agricultural production shelters plants from stochasticity and increases propagule pressure, enhancing the potential for low-risk species to take advantage of rare dispersal opportunities. Weed risk assessments of M. × giganteus assume the rarity of events such as scouring and flooding that would facilitate secondary dispersal of vegetative rhizome fragments and the long-term sexual inviability of escapes. Combining data from small-scale rhizome fragmentation and movement experiments, and estimates from the literature, we parameterized an individual-based model to examine M. × giganteus spread given three dispersal scenarios. We further evaluated our estimates in response to different field edge buffer widths and monitoring intensities, two key strategies advised for containing biofuel crops. We found that clonal expansion from the field edge alone was sufficient to allow the crop to outgrow buffers of 3 m or less within 11 to 15 yr with low monitoring intensities. Further, models that included the possibility of rhizome dispersal from fields and scouring at field edges demonstrate the potential for long-distance dispersal and establishment with inadequate management. Our study highlights the importance of considering minimum enforced management guidelines for growers to maintain the ecological integrity of the agricultural landscape.

European swallowwort [Vincetoxicum rossicum (Kleopow) Barbarich] is found in the northeastern United States and southeastern Canada. It forms dense growth patterns that reduce plant and insect biodiversity, and lab assays show that it produces allelopathic compounds that affect microbial activity. Consequently, we hypothesized that V. rossicum alters soil microbiome composition and activity in invaded habitats, which may impact ecosystem properties and processes. We sampled soil from a similar time point within a growing season at each of five sites in New York State where V. rossicum was both present and absent. We measured bacterial and fungal microbiome composition, available soil nitrogen (N), soil respiration (CO2 flux), and soil extracellular enzyme activities. Microbial composition varied across field sites, but only fungal composition was affected by invasion. No significant differences were found between the invaded and uninvaded plots at any of the sites for available soil ammonium, nitrate, or respiration, though extractable N varied greatly between sites. Microbial hydrolytic extracellular enzyme activities suggest decreased protein degradation and increased oxidative enzyme activity with V. rossicum invasion, which is relevant to soil N and carbon cycling processes. Although V. rossicum impacted rhizosphere microbial composition and activity, it was not associated with large perturbations in ecosystem function when examined across multiple invasion sites during this short-term study.

Establishment of nonindigenous (NI) aquatic plants in the nearshore regions of freshwater ecosystems has resulted in environmental degradation, recreation concerns, economic impacts, and substantial management challenges. To reduce these undesirable effects, NI aquatic plants are often targeted for removal or control by management agencies, but the efficacy of implementation is often not documented or sustained. In this study, we developed a management plan to completely remove all NI plants from Emerald Bay, Lake Tahoe, CA, using only physical control techniques. Management plan priorities were based on previous research and lessons learned, including the need for (1) integrated weed management using multiple physical control techniques, (2) a large initial treatment investment, (3) ongoing early detection and rapid response, (4) detailed ecological monitoring, and (5) a long-term commitment to annual maintenance removal. Application of this management plan resulted in complete removal of all NI aquatic plants from Emerald Bay and substantial cost savings each year after the initial large investment. Annual maintenance removal and monitoring will need to continue as long as NI aquatic plants continue to enter Emerald Bay on boats and currents from other areas of Lake Tahoe.