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Evaluamos el efecto de una ruta como inhibidora del desplazamiento de las aves, dentro de La Reserva Provincial La Florida (Tucumán, Argentina). Esta ruta divide la reserva, separando un fragmento del resto del bosque. Durante 12 meses realizamos muestreos mensuales de aves con redes de niebla instaladas a ambos lados de la ruta, y censamos las aves que atraviesan la ruta. Los individuos capturados fueron clasificados en sedentarios (capturados más de una vez) y transeúntes (1 captura). Si la ruta inhibe la llegada de nuevos individuos al fragmento (FG), el porcentaje de aves sedentarias en este sitio debería ser mayor que en el bosque continuo (BC). En las redes capturamos 1742 aves (34 especies); la riqueza fue similar para ambos sitios (27 vs. 28). El número de sedentarios no mostró diferencias entre sitios (BC=234, FG=194), al igual que el porcentaje mensual de aves sedentarias capturadas. Los transeúntes fueron más abundantes en el BC (809 vs. 505); la abundancia de Turdus rufiventris fue responsable de esta diferencia. En los censos en la ruta observamos 622 aves (28 especies). La cantidad de registros de T. rufiventris cruzando la ruta (33.8% del total de aves censadas) indicaría que esta barrera no afecta sus desplazamientos. Algunas especies frecuentes en las redes, fueron poco o no fueron detectadas cruzando la ruta, sugiriendo que sus desplazamientos podrían estar inhibidos por la ruta. Sin embargó, ninguna de estas especies mostró diferencias entre sitios en el porcentaje de aves sedentarias capturadas mensualmente. Los resultados de este trabajo sugieren que las aves estudiadas no están significativamente afectadas por la discontinuidad producida por la ruta. Estos resultados podrían no ser extrapolables a otras áreas de bosque, que requirirían estudios propios. We studied the effect of a road on bird movements at La Florida Provincial Reserve (Tucumán, Argentina). A road cuts the reserve leaving a forest fragment detached from the continuous forest. Understory birds were captured monthly for 12 months using 12-15 mist nets located in forest sites on both sides of the road, and birds crossing the road were censused to estimate movement between the fragment (FG) and the continuous forest (CF). The captured birds were classified as site-attached (captured more than once) and transient individuals (one capture). If the road reduced the arrival of new individuals into the FG, the proportion of site-attached captures would be expected to be larger here than in the CF. We captured 1742 birds (34 species). Richness was similar for both sites (CF=27, FG=28). Site-attached abundance showed no differences between sites (CF=234, FG= 194), as well as the percentage of site-attached birds captured monthly. Transient individuals were significantly more abundant in continuous forest (809 vs. 505); Turdus rujiventris abundance was responsible for this difference. In censuses we observed 622 individuals (28 species). The high frequency of T. rujiventris individuals crossing the road (33.8% from total birds censused) suggests that this barrier should not affect their movements. Some species commonly captured in the nets were not detected crossing the road, suggesting that they may be affected by the road. However, none of these species showed differences between sites in the percentage of site-attached captured monthly. Finally, our results suggest that understory birds are not significantly affected by the discontinuity produced by the road. These results could not always be extrapolated to other forests, that would require particular studies.

Currently biological invasions are considered one of the world’s most serious conservation problems. Ligustrum lucidum is the most abundant exotic tree in secondary forest patches of montane forests of NW Argentina. We studied the determinants of success of the early stages of its life cycle in distinct habitat types, with the hope of identifying vulnerabilities that could be exploited to control the invasion. Seed arrival, germination, seedling recruitment and survival, and sapling growth were studied in edges, gaps and forest interior. Seed arrival was also assessed under perches and in open fields. Germination was studied in forest and grass-land patches. L. lucidum seedling survival and sapling growth were compared with the most abundant native species survival and growth. Seed arrival was strongly seasonal with a peak in mid-August. Seed rain did not differ significantly among habitat types, however there was a tendency for edges to receive more seeds when only dispersed seeds were considered. Perches strongly enhanced seed arrival; more than 40 times the number of seeds were dispersed beneath citrus plants (i.e. perches) than found in paired open areas. In the forest, seeds in gaps and edges had higher germination rates, but there was no difference in seedling survival. Fruits under closed canopy exhibited the lowest germination. Germination and survival were low in open areas. Neither seedling recruitment nor sapling growth differed between gaps and forest interior. L. lucidum saplings grew significantly more than saplings of the most common native species, and also showed higher seedling survival. L. lucidum is a prolific fruit producer, is capable of germinating and surviving in a broad range of forest environments, it is relatively shade tolerant and has higher survival and faster growth rate in comprison to the most common native species. All these characteristics highlight its potency as a successful invader, and point to few vulnerabilities that could be targets of control measures.Las invasiones biológicas son consideradas actualmente uno de los problemas de conservación más serios. Ligustrum lucidum es el árbol exótico mas abundante en los bosques secundarios del NO de Argentina. Estudiamos llegada de semillas, germinación, reclutamiento y crecimiento de renovales en claros, bordes e interior del bosque La llegada de semillas también se estudió bajo perchas y en sitios abiertos. La supervivencia y el crecimiento de renovales de L. lucidum fueron comparados con los de las especies nativas mas abundantes. El arribo de semillas fue estacional y los bordes mostraron una tendencia a recibir mas semillas dispersadas. La presencia de perchas aumentó la llegada de semillas. Dentro del bosque, las semillas germinaron mas en claros y bordes, pero no hubo diferencia en sobrevivencia. La germinación y la supervivencia fue baja en sitios abiertos. El reclutamiento y crecimiento de renovales no difirió entre claros e interior del bosque. Los renovales de L. lucidum crecieron mas que los renovales de las especies nativas mas comunes. L. lucidum se establece y sobrevive en un amplio rango de condiciones, es relativamente tolerante a la sombra y tiene una rápida tasa de crecimiento. Estas características indican su capacidad invasora, y señalan escasas vulnerabilidades que puedan ser usadas para su control.