Invasive species pose a threat to the livelihoods of many people living on rangelands of the western United States. Invasive species impact many ecosystem goods and services of the areas they invade and represent one of the largest causes of habitat degradation. On private ranches, economic analyses often find that conservation practices, such as invasive species control, are not economically viable, in contrast to what is found at the landscape scale. In northeast Wyoming, ventenata [Ventenata dubia (Leers) Coss.] is a relatively new invader in the Great Plains ecoregion that threatens forage production on ranches. Our objective was to explore the economic costs of V. dubia for two options available to a ranch operation: purchasing extra hay to offset losses in forage and controlling V. dubia with herbicide. Using a partial budget analysis, we compare these two options in three invasion scenarios using a range of forage utilization rates and discount rates. Controlling V. dubia with herbicide was a cheaper option compared with purchasing additional hay in many cases. In fact, at 50% utilization, it is cheaper to control V. dubia in all of our scenarios at all discount rates given our assumptions. For lower grazing utilization rates, it becomes cheaper to purchase hay in some cases other than in our worst-case invasion scenario. In these cases, coordination among ranchers is needed to effectively control V. dubia. There are many ranch-specific differences that may make a different option more feasible, and we did not explore options of reducing herd sizes. However, our results suggest that controlling V. dubia can be an economically viable option under certain circumstances. Additional assistance in the form of a cost-share program, and facilitation of coordination is needed to overcome the difficulties of private management of invasive species.

Tourism, one of the world largest economic sectors, moves a substantial body of individuals and materials about the world and is implicated in the spread of invasive plants and is itself impacted by biological invasions that can degrade touristic landscapes and affect destination communities. Tourists constitute not only an immediate biological threat, but through their landscape and biota preferences also constitute a substantial economic and ecological force that has implications for invasive plant management in destinations. Tourists and the tourism industry are therefore significant stakeholders in invasive plant introduction, spread, and management. This paper discusses an onsite survey (n = 231) of domestic and international visitors in New Zealand, a destination where invasive species are an important ecological and economic issue. Findings show that visitors have a low understanding of the presence and level of threat of invasive plants and express preferences for some plants that are highly invasive. However, there were substantial variations across the international sample, with visitors from Asian and European ethnicities expressing significantly different attitudes toward a range of invasive plants. Asian visitors were more likely to show preferences for some plants that were seriously invasive and to be more accepting in general of invasive plants within landscapes and less supportive of invasive species eradication. These findings suggest that attitudes toward invasive plants and their management may be culturally determined, which poses challenges for managers aiming to generate awareness and support from across diverse tourist cohorts for invasive species control. There are also challenges for gaining support from the tourism industry for invasive plant control programs where particular “charismatic” or attractive invasive plants may contribute to touristic landscapes and visitor itineraries.

Brazilian peppertree (Schinus terebinthifolia Raddi) is an aggressive shrub that infests more than 280,000 ha in Florida. Individual plant treatments (IPT), including basal bark and cut stump application with triclopyr butoxyethylester and triethylamine formulations, respectively, have been used for decades. While they are both effective, resprouting can occur, which requires retreatment for control. Recent research on other woody invasive plants has indicated additional non-crop herbicides used in natural areas can be effective with these IPT techniques and therefore warrant testing on S. terebinthifolia. In 2018 and 2019, basal bark and cut stump studies were conducted at Cape Canaveral Air Force Station in natural areas infested with S. terebinthifolia. In the basal bark application studies, we found aminocyclopyrachlor applied at 12 and 24 g L−1 and triclopyr acid applied at 34 and 69 g L−1 each provided 100% defoliation of multistemmed S. terebinthifolia individuals with a mean root collar diameter up to 20.2 cm at 360 d after treatment (DAT). These were not different from triclopyr ester applied at 96 g L−1. Imazamox applied at 30 g L−1 resulted in 86% defoliation at 360 DAT. However, we observed formulation incompatibility when imazamox was mixed with basal bark oil which may limit its utility. In cut stump studies, we found aminocyclopyrachlor and aminopyralid each individually applied at 6, 12, and 24 g L−1, resulted in stump mortality that was not different from the commercial standard triclopyr amine applied at 180 g L−1. Similar results were found for a triclopyr acid formulation applied at 86 and 172 g L−1 and imazamox applied at 60 g L−1. For both treatment techniques, we found that alternative treatments provided control at lower herbicide concentrations than triclopyr ester and amine commercial standards. These results advance our understanding of IPT and expand access to additional effective herbicide options for S. terebinthifolia management.

Invasive shrubs often present extremely difficult challenges for individual plant treatment approaches due to multiple basal stems with complex branching patterns. Basal bark and cut stump individual plant treatments have been the standard methods for managing large-statured shrubs, while hack and squirt has been disregarded as operationally too difficult. However, hack and squirt is a more discriminant treatment technique that may lead to a reduction in herbicide use. Here, we evaluated the speed, herbicide use, and performance of a reduced hack and squirt approach using single hacks per stem injected with 0.5 ml of either aminocyclopyrachlor (240 g L−1) or aminopyralid (240 g L−1) against conventional low-volume basal bark treatment with triclopyr ester (96 g L−1) and cut stump treatment with triclopyr amine (180 g L−1). The experiments were conducted on three subtropical shrub species: Eugenia uniflora, Lagerstroemia indica, and Schinus terebinthifolia. Across species, we found the reduced hack and squirt approach resulted in comparable treatment efficacy to basal bark and cut stump treatment, was faster than cut stump treatment, and used less herbicide and carrier than basal bark treatment. A single hack per stem is a significant shift for hack and squirt treatment, which typically employs a narrow or continuous spacing of hacks around the entire circumference of each stem. Future work should seek to clarify the applicability of this approach over a wide range of invasive shrubs.

Old World climbing fern [Lygodium microphyllum (Cav.) R. Br] is a smothering vine that has invaded thousands of hectares of wetlands in southern and central Florida, including the Everglades. For more than two decades, the standard management approach in natural areas has been to cut the vines at waist height, leaving climbing rachis to desiccate in the tree canopy (poodle cutting) and subsequently treat all rooted ground cover with a foliar application of a 3% v/v solution of glyphosate. While this is generally effective, there is increasing interest in providing additional control options and more selective treatments. Along with glyphosate, triclopyr is widely used in invasive plant management and may also provide increased selectivity when treating the ground cover. However, it has not been well tested on L. microphyllum, especially the more recently developed acid and choline formulations. In a series of field trials, we compared the acid, amine, and choline formulations of triclopyr against glyphosate as a positive reference and nontreated plots as a negative reference based on control of L. microphyllum at three wetland sites in southern Florida over the period of 2016 to 2020. Significant reductions in L. microphyllum cover were measured at 1 mo after treatment (MAT) and continued to the termination of the studies at 12 and 28 MAT. We found all three triclopyr formulations applied with a single-nozzle backpack sprayer at 5.4 g ae L−1 provided comparable activity to glyphosate applied at 14.4 g ae L−1. There were few differences in L. microphyllum efficacy among the three triclopyr formulations at each site. These results indicate that triclopyr is a suitable alternative to glyphosate for L. microphyllum control in wetland ecosystems. Future research should evaluate triclopyr efficacy on L. microphyllum in varied hydrologic conditions to better refine treatment prescriptions for wetlands.