In this study, we provide a comprehensive and updated inventory of the non-native vascular flora of continental Ecuador and analyze its key biogeographic and ecological attributes to inform biological invasion management. We recorded 486 non-native wild plant taxa, 52% of which are naturalized and 48% casual. This inventory was primarily based on secondary data (published literature, scientific reports, and online databases) and enriched through fieldwork and expert consultations. It includes information on taxonomy, life form, lifespan, origin, first year of record, and spatial-temporal distribution. The most represented families were Poaceae (16%), Asteraceae (10%), and Fabaceae (9%). About 60% of the taxa originated from Asia and/or Africa, and 67% are herbs. The earliest introductions date back to the late 18^th century, with an exponential increase beginning in ca. 1915. Only 13% of the taxa have a minimum residence time exceeding 125 years. The Andes accounted for the highest number of taxa (93%, including taxa shared with other regions). Nearly 80% of the non-native taxa have documented uses, most commonly ornamental (42%) and medicinal (38%). Naturalized taxa tended to have longer residence times and more frequently reported uses than casual ones, suggesting these traits may influence naturalization likelihood. Due to limited systematic sampling across the country, particularly outside the Central Andes, some spatial bias may exist. However, the integration of citizen science-derived data, a methodological innovation in our study, proved to be a promising approach for addressing knowledge gaps and improving detection efforts in regions with limited research capacity. Our findings offer a foundation for advancing the management of biological invasions in Ecuador through early detection, rapid response (EDRR), and species prioritization. Finally, we provide a practical, adaptable and replicable framework, based on citizen science and appropriate statistical analyses, for developing national inventories of non-native plant species in data-deficient countries.

Ecuador, recognized as a megadiverse country, faces growing threats from biological invasions, particularly in the mountainous ecosystems of the Andes. We described patterns of native and non-native plant richness and diversity along an elevational gradient (2,000–4,400 m a.s.l.) on the Tungurahua volcano, testing whether patterns of non-native plant diversity are consistent with directional environmental filtering along the gradient or explained by the effects of residence time, climate-matching, and disturbance intensity. Twenty-five 10 × 2 m transects were established at 100-m elevational intervals following a MIREN-T-adapted protocol. Vegetation cover, abundance, and disturbance were recorded in each plot. A total of 247 taxa were identified, distributed across 75 families and 171 genera. Of these, 180 were native (including 11 endemic), 38 non-native, and the remainder of undetermined origin. Non-native taxa were predominantly herbaceous and originated from Africa, Europe, and Asia. Along the gradient, non-native taxa were concentrated at lower elevations, with narrower elevational ranges and lower maximum elevations than native taxa. Native richness exhibited a mid-elevation peak (~ 3,400 m), whereas non-native richness declined steadily with elevation. Alpha diversity decreased with elevation in both groups, but sharply in non-natives. Beta diversity analyses showed higher turnover among native assemblages, while non-native communities were more homogeneous along the gradient. Overall, these patterns support the directional environmental filtering hypothesis, with climatic constraints limiting the upslope expansion of non-native taxa and weaker evidence for effects of residence time, climate-matching, or disturbance intensity. These findings provide key insights for the management and conservation of tropical mountain ecosystems.

Protected areas (PAs) are central to biodiversity conservation, yet they are increasingly exposed to biological invasions. In continental Ecuador, information on non-native terrestrial spermatophytes in PAs remains scattered across biodiversity platforms, scientific and grey literature, and management documents, limiting broad-scale assessments and management planning. We compiled, validated, and integrated records of non-native terrestrial spermatophytes across 68 continental PAs of the Ecuadorian National System of Protected Areas ( Sistema Nacional de Áreas Protegidas , SNAP its Spanish acronym) using GBIF, iNaturalist, peer-reviewed and grey literature, official management plans, and complementary field observations. Records were taxonomically standardized, curated, and assigned to individual PAs. To explain variation in non-native richness, we evaluated predictors grouped into four categories: PA basic attributes (e.g., extent, year of PA designation), propagule pressure and introduction pathways, anthropogenic disturbance, and abiotic environmental conditions. PA basic attributes (e.g., extent, year of PA designation), propagule pressure and introduction pathways, anthropogenic disturbance, and abiotic environmental conditions. Total non-native taxon richness was modelled using generalized linear models (GLMs). We compiled and validated 3,480 occurrence records, including 2,117 observations from citizen science platforms, 687 herbarium specimens, 371 records from peer-reviewed articles, 123 field observations, 106 thesis records, and 76 inventory records derived from management documents. These records represented 486 non-native taxa from 86 families and 320 genera. Poaceae (55 taxa), Asteraceae (38), and Fabaceae (37) were the richest families, together accounting for approximately 27% of all non-native taxa. Across the full dataset, 204 taxa were recorded only in the wild, 188 only as cultivated, 90 in both conditions, and four remained uncertain in establishment status. Seventeen (25%) PAs had no recorded non-native taxa, whereas Pululahua Geobotanical Reserve and Cayambe-Coca National Park were the richest, with 174 and 172 taxa, respectively. Nearly half of all taxa (47.3%) were recorded in only one PA, while the most widespread taxa, Taraxacum sect. Taraxacum and Trifolium repens , occurred in 17 PAs each. Our dataset included four of the species listed among the world’s worst invasive alien species: Arundo donax , Leucaena leucocephala , Rubus ellipticus , and Spathodea campanulata . The selected GLM identified year of PA designation, extent, distance to the nearest urban area, human density, road density, median human impact, terrain ruggedness, and management type as the main predictors of non-native richness. Richness increased with time since PA designation, extent, road density, median human impact, and terrain ruggedness, while state-managed PAs showed lower expected richness. These results indicate that non-native spermatophytes richness in PA is strongly shaped by propagule pressure, human accessibility, and landscape complexity. Notably, richness increased with time since PA designation, a pattern that contrasts with expectations and may be associated with cumulative introduction history or differences in sampling effort among PAs. This study provides the first integrated national baseline of non-native terrestrial spermatophytes across continental Ecuadorian PAs. By combining heterogeneous data sources into a standardized workflow, it provides a practical foundation for surveillance, early detection, and prioritization of management in a biodiverse yet under-assessed PA network.

Mountain regions worldwide harbour key and unique biodiversity, yet they are increasingly threatened by multiple human pressures projected to intensify throughout the 21 ^st century. While invasive species are widely recognized as one of the main drivers of global biodiversity loss, until recently, their pressure in alpine and montane systems remained relatively low. But recent evidence suggests that this situation is changing. Climate warming, land-use change, pollution, and increasing rates of alien species introductions are enabling invasive plants to expand into previously less disturbed mountain habitats. Understanding the mechanisms behind this process is essential for predicting future invasions and preventing their impacts. In this study, we assess the magnitude and mechanisms of the negative environmental impacts caused by alien plant species in mountain ecosystems worldwide. Specifically, we obtained a list of 564 species recorded as naturalized across 18 mountain regions, from standardized road surveys along elevational gradients conducted by the Mountain Invasion Research Network (MIREN). We evaluated these species using the Environmental Impact Classification for Alien Taxa (EICAT), an objective and transparent method recognized by the IUCN. EICAT classifies alien species according to the severity of their impacts on native species populations and allows for the classification of the mechanisms driving these impacts. Documented impacts occurring in both mountain and non-mountain ecosystems were included in the assessment. Our preliminary results suggest that empirical evidence on the environmental impacts of most alien plant species remains limited or entirely lacking, particularly in mountain environments. For the species with available information, the most frequently reported impact mechanisms include competition with native species as well as indirect effects mediated through interactions with other organisms (such as disruption of pollinator networks) and allelopathic effects. Overall, this study provides a global overview of the potential impacts of alien plants in mountain ecosystems and establishes a robust scientific foundation for prioritization and the development of targeted management recommendations.