The dry forest of southern Ecuador and northern Perú (called the Tumbesian region) is known for its high diversity, endemism, and healthy conservation state. Nevertheless, the forest is exposed to many threats linked with human activities. To understand the effects of these threats, which have not been appropriately assessed, we pose two questions: (a) What are the diversity and structural situations of the forest? (b) Are anthropogenic activities affecting the composition and structure of the forest? The assessed factors were species richness, diversity, species similarity, abundance, and density. Forest information was obtained from 72 plots (total area 25.92 ha) randomly placed to cover a wide range of stand densities (from 200 to 1100 m a.s.l.). After constructing linear mixed models and selecting the most influential one, we determined the individual influences of 12 predictors. The human pressure index (HPI) was the most negative predictor of forest health, and annual precipitation was the most important abiotic predictor of good health conditions. Livestock grazing did not significantly change the diversity and structure of mature forest. The mean annual temperature and stoniness influenced only the basal area and number of individuals, respectively. The species composition in our study area was not affected by the HPI, but was strongly predicted by annual precipitation.

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.

Climate and atmospheric changes are impacting forest function and structure worldwide, but their effects on tropical forest diversity are unclear. Nowhere is the scientific challenge greater than in the Andes and the Amazon, which together include the world’s most diverse forests. Here, using 406 permanent plots spanning four decades of intact lowland and montane forest dynamics, we test for long-term change in species richness and assess the influence of climate and other variables. We show that, at a continental scale, species richness appears stable, but this masks substantial regional variation. Species richness increased in Northern Andean and Western Amazon plots, yet declined in the Central Andes, Guyana Shield and Central-Eastern Amazon. Overall, warmer, drier and more seasonal forests lost species, while those at higher elevations, in less fragmented areas and with faster rates of tree turnover experienced increases. Region-specific drivers, particularly precipitation seasonality and demographic factors, modulated these trends. The results highlight the diverse ways in which Amazon–Andes forests are changing and underscore the critical need to preserve large-scale ecosystem integrity to maintain local tree diversity. By doing so, Northern Andean forests in particular could serve as an important refuge for species increasingly displaced by climate change.

ESTRUCTURA Y COMPOSICIÓN FLORÍSTICA DEL BOSQUE SIEMPREVERDE MONTANO BAJO DE LA PARROQUIA SAN ANDRÉS, CANTÓN CHINCHIPE, PROVINCIA DE ZAMORA CHINCHIPE, ECUADOR