The benefits of early detection of biological invasions are widely recognized, especially for protected areas (PAs). However, research on incipient invasive plant species is scarce compared to species with a recognized history of invasion. Here, we characterized the invasion status of the non-native conifer Juniperus communis in PAs and interface areas of Andean Patagonia, Argentina. We mapped its distribution and described both the invasion and the environments this species inhabits through field studies, a literature review, and a citizen science initiative. We also modeled the species’ potential distribution by comparing the climatic characteristics of its native range with those of the introduced ranges studied. The results show that J. communis is now widely distributed in the region, occurring naturally in diverse habitats, and frequently within and close to PAs. This species can be considered an incipient invader with a high potential for expansion in its regional distribution range, largely due to its high reproductive potential and the high habitat suitability of this environment. Early detection of a plant invasion affords a valuable opportunity to inform citizens of the potential risks to high conservation value ecosystems before the invader is perceived as a natural component of the landscape.

Invasive species impact native ecosystems through associations with local biota; however, these co‐occurrences and potential interactions remain poorly understood, particularly for small organisms like insects. Citizen science provides a valuable tool, providing broad spatial and temporal coverage to facilitate the observation of species co‐occurrences. Our aim was, using citizen science records, to detect co‐occurrences and potential novel interactions between the invasive ladybird Harmonia axyridis and local biota (plants, arthropods and fungi) in Argentina. Over 50% of the photos showed H. axyridis in association with another species, mainly from the plant families Asteraceae, Rosaceae and Lamiaceae and the arthropod families Aphididae and Coccinellidae. In addition, we report potential novel interactions including predation, parasitism, interspecific mating and mixed aggregations with local biota that have not been previously documented in Argentina, providing new insights into possible ecological impacts of this invasive ladybird. Our findings highlight how citizen science can be used as a research prioritization tool for invasive species research, revealing species co‐occurrences and also uncovering potential novel interactions between invasive species and local taxa across large spatial and temporal scales.

Los hongos ectomicorrícicos (HEcM) son esenciales para las plantas y los ecosistemas, especialmente luego de grandes disturbios como los incendios. Los bosques y matorrales Andino-patagónicos tienen asociados a su dinámica el fuego como disturbio natural, aunque en la actualidad los incendios ocurren de manera más frecuente e intensa. Los estudios sobre las comunidades de HEcM suelen realizarse en condiciones de campo o de vivero, siendo la utilización conjunta de ambos enfoques poco frecuente. En este trabajo se compararon los efectos del fuego sobre la colonización, abundancia, diversidad taxonómica y funcional de comunidades de HEcM asociadas a Nothofagus antarctica (ñire) a través de dos enfoques complementarios: 1) luego de un incendio en condiciones naturales de campo y 2) mediante quemas experimentales en vivero. Se observó que mientras los porcentajes de colonización sólo se vieron afectados negativamente por el fuego en condiciones de campo, este disturbio impactó de forma negativa en la riqueza, diversidad taxonómica y composición de las comunidades de HEcM en plantas tanto de campo como de vivero. La diversidad funcional (tipos exploratorios) también se vio afectada por el fuego, reduciéndose la ocurrencia y abundancia de ectomorfotipos con mayor complejidad estructural. Conocer la dinámica de las comunidades de HEcM del suelo es relevante, debido a que pueden ayudar a los ecosistemas a recomponerse luego de los incendios, los cuales se proyectan más severos y frecuentes en la región.