Citizen science is becoming very useful in surveying and monitoring biodiversity. Within the European Union LIFE medCLIFFS project, a network of volunteers has been established for the detection and long-term monitoring of invasive plant species that threaten the endemic flora of Mediterranean cliffs in northeastern Spain. Through iNaturalist, volunteers record various data along a series of 1-km transects. Based on the ca. 700 observations collected by volunteers in 2023 (the first year of the project), a simple and visually attractive methodology for assessing the recorded populations has been developed. This method classifies populations into one of three population dynamics categories: (1) propagative behavior (i.e., populations with seedlings or young plants but lacking senescent or dead individuals); (2) senescent behavior (i.e., showing senescent/dead plants but lacking seedlings/juveniles); and (3) a mixed behavior (i.e., containing both). This methodology, whose outputs are easily interpretable as heat maps, allows the collection of large datasets on invasive plants by citizen scientists, with two main purposes: (1) knowing which species are most concerning based on simple, straightforward observations of their population dynamics; and (2) identifying which regions of the study area are more problematic and where management efforts should therefore be directed.

Reduced hack and squirt (RHS) is a herbicide-injection technique that controls woody species with a limited number of hacks. When used with aminopyralid or aminocyclopyrachlor, the technique controls multistemmed shrubs such as Brazilian peppertree (Schinus terebinthifolia Raddi) and Surinam cherry (Eugenia uniflora L.). However, additional data are needed to compare its effectiveness on other woody invasive species against standard individual-plant treatment techniques. We compared RHS with aminocyclopyrachlor or aminopyralid administered with 0.5 ml of undiluted concentrate (240 g L^–1) against traditional basal bark and cut stump techniques using triclopyr at 96 and 120 g L^–1, respectively, on six invasive trees in Florida, USA. For all species tested, the RHS technique with aminocyclopyrachlor was not different or was more effective than basal bark or cut stump treatment with triclopyr. The RHS technique with aminopyralid was effective on certain species but did not control as many species as RHS with aminocyclopyrachlor or cut stump treatment with triclopyr. The RHS technique required significantly less time than cut stump treatment but was not different from basal bark treatment. Across all species, when compared with basal bark and cut stump treatment with triclopyr, the RHS approach resulted in reductions of average total herbicide mix applied by 98% and 89%, respectively. For herbicide active ingredient, when compared with basal bark and cut stump treatment with triclopyr, RHS resulted in reductions of 95% and 86%, respectively. These results indicate that when compared to conventional individual plant treatment (IPT) approaches with triclopyr, the RHS approach yielded a high level of target efficacy on a broad spectrum of species, comparable or shorter application times, and substantial reductions in herbicide mix and active ingredient applied. Future research should seek continued refinement of this technique for woody plant control on other troublesome invaders.