Carbon and water vapor balance in a subtropical pine plantation

Afforestation has been proposed as an effective tool for protecting primary and/or secondary forests and for mitigating atmospheric CO2. However, the dynamics of primary productivity differs between plantations and natural forests. The objective of this work was to evaluate the potential for carbon storage of a commercial pine plantation by determining its carbon balance. Measurements started when trees were aged 6 and ended when they were older than 8 years. We measured CO2 and water vapor concentrations using the Eddy covariance method. Gross primary productivity in 2010 and 2011 was 4290 ± 473 g C m-2 and 4015 ± 485 g C m-2, respectively. Ecosystem respiration ranged between 7 and 20 g C m-2 d-1, reaching peaks in all Februaries. Of the 30 months monitored, the plantation acted as carbon source for 21 months and as carbon sink for 6 months, while values close to neutrality were obtained during 3 months. The positive balance representing CO2 loss by the system was most likely due to the cut branches left on the ground following pruning activities. The plantation was subjected to pruning in January and September 2008 and to sanitary pruning in October 2010. In all cases, cut branches were not removed but remained on the ground. Residue management seems to have a very important impact on carbon balance.Inst. de Clima y AguaFil: Posse Beaulieu, Gabriela. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Clima y Agua; ArgentinaFil: Lewczuk, Nuria. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Clima y Agua; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Richter, Klaus. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Clima y Agua; ArgentinaFil: Cristiano, Piedad María. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución. Laboratorio de Ecología Funcional; Argentin

Uncertainties in fPAR estimation of grass canopies under different stress situations and differences in architecture

The fraction of intercepted photosynthetic active radiation (fPAR) is a key variable used by the Monteith model to estimate the net primary productivity (NPP). This variable can be assessed by vegetation indices (VIs) derived from spectral remote sensing data but several factors usually affect their relationship. The objectives of this work were to analyse the fPAR dynamics and to describe the relationships between fPAR and several indices (normalized difference vegetation index (NDVI), optimized soil adjusted vegetation index (OSAVI), GreenNDVI (GNDVI), visible atmospherically resistant index (VARI) green, VIgreen and red edge position (REP)) under different water and nutrient treatments for two species with different canopy architectures. Two C3 grass species with differences in leaf orientation (planophile and erectophile) were cultivated from seeds in pots. Four treatments were applied combining water and nitrogen availability. Every week, canopy reflectance and fPAR were measured. Aerial biomass was clipped to estimate final above-ground production for each species and treatment. Starting from reflectance values, the indices were calculated. Planophile species have a steeper (but not significantly) slope inVIs-fPAR relationships than the erectophile species. Water and nutrient deficiencies treatment showed no relationship with fPAR in any spectral index in the erectophile species. In the other species, this treatment showed significant relationship according to the index used. Analysing each species individually, treatments did not modify slopes except in one case (planophile species between both treatments with high nitrogen but differing in water availability). Among indices, GNDVI was the best estimator of fPAR for both species, followed by NDVI and OSAVI. Inaccurate results may be obtained from commonly reported spectral relationships if plants' stress factors are not taken into account.Fil: Cristiano, Piedad María. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación de Recursos Naturales. Instituto de Clima y Agua; ArgentinaFil: Posse, G.. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación de Recursos Naturales. Instituto de Clima y Agua; ArgentinaFil: Di Bella, Carlos Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación de Recursos Naturales. Instituto de Clima y Agua; ArgentinaFil: Jaimes, Florencia Romina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación de Recursos Naturales. Instituto de Clima y Agua; Argentin

Seed dormancy and germination of native and invasive alien woody species of an endangered temperate forest in the Argentine Pampas

Forest restoration plans can benefit from knowledge of seed ecophysiology. Naturally, seeds respond to environmental clues to trigger germination or persist in the seed bank. Controlling dormancy and germination moment in native species will allow more efficient seed management, both for direct seeding (in situ restoration) and for native plant cultivation in nurseries (ex situ restoration). In addition, the differences in germination conditions of native and alien invasive trees can be used as control windows of the alien species in the seed bank. The aim of this study was to identify the environmental factors regulating seed dormancy and germination of native and alien trees of the Talares, an endangered temperate forest of the Argentine Pampas region. Seeds of the native trees Schinus longifolius, Jodina rhombifolia, Celtis tala and the alien trees, Ligustrum lucidum, Ligustrum sinense and Gleditsia triacanthos were collected and the presence of dormancy was determined exposing the seeds to standard germination protocols. In case of dormancy presence, a post-maturation experiment was carried out in two conditions: i) cold and wet (stratification) and ii) dry and warm (after-ripening). The native species J. rhombifolia and C. tala showed seed dormancy but S. longifolius did not. For C. tala germination it was necessary a previous post-maturing process; however, environmental conditions for J. rhombifolia germination were not attained. Alien species showed a high germination, reaching up to 100% in at least one of the evaluated conditions, and displayed different emergence windows compare to natives. Since alien species germinated at lower temperatures than natives, a temporal window for chemical or mechanical control is proposed. Ecophysiology of seed dormancy and germination facilitates strategies for decision makers, as it can make native seeds use and aliens control more efficient to meet global restoration goals.Fil: Lacoretz, Mariela Verónica. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución. Laboratorio de Ecología Funcional; ArgentinaFil: Malavert Pineda, Cristian Jonatan. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; ArgentinaFil: Madanes, Nora. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución. Laboratorio de Ecología Funcional; ArgentinaFil: Cristiano, Piedad María. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución. Laboratorio de Ecología Funcional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; ArgentinaFil: Tognetti, Pedro Maximiliano. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentin

La Red de Viveros de Plantas Nativas de Argentina (REVINA): Una perspectiva etnobotánica para fortalecer la restauración de ecosistemas en la Argentina

La Red de Viveros de Plantas Nativas de Argentina (REVINA) vincula a diferentes actores sociales involucrados en producir plantas nativas, en ponerlas en valor y en restaurar los ecosistemas de la Argentina. Fortalecer la red es fundamental para cumplir con las metas de restauración del país, teniendo en cuenta que la comunidad de viveristas generará las especies de plantas que serán los insumos primordiales de los proyectos de restauración. En este trabajo se estudió la red de viveros de plantas nativas, la comunidad de viveristas y las plantas que éstos producen, con el fin de fortalecer los proyectos de restauración en nuestro país a través de relevar los participantes de los encuentros anuales de la REVINA entre 2016 y 2020. Observamos que la red ha crecido notablemente desde su creación, lo cual refleja que el interés por las plantas nativas ha aumentado en los últimos años. En su mayoría, las especies vegetales que se cultivan en los viveros pertenecen a la familia Fabaceae, son leñosas, y presentan un sesgo fuerte hacia especies del centro-este del país, en consonancia con el número de viveros que se concentra en esa región. La mayor parte de los viveros tiene una producción pequeña, aunque a lo largo de los años se sumaron viveros productores de mayor tamaño. La perspectiva utilizada permitió obtener una primera lista de viveros de plantas nativas y de las especies que éstos cultivan. Finalmente, se proponen algunos aspectos a mejorar para fortalecer esta red de actores y así cumplir con las iniciativas de restauración del país.The Argentine Native Plant Nursery Network (REVINA) links different social actors involved in native plant production, their valorization and the restoration of Argentina’s ecosystems. It is essential to strengthen the network in order to meet the country’s restoration goals, considering that the nursery community will generate the plant species that will be the primary inputs for restoration projects. In this paper we study the native plant nursery network, the nursery community and the plants they produce, in order to strengthen restoration projects in Argentina through the survey of the participants of the annual meetings of the REVINA in the period 2016-2020. We observed the network has grown remarkably since its creation, reflecting the increasing interest in native plants in recent years. Most of the plant species grown in the nurseries belonged to the Fabaceae family, are woody, and show a strong bias towards species from the centre-east of the country, in line with the number of nurseries concentrated in that region. A great number of nurseries have a small production, although, over the years, larger nurseries joined the network. The perspective used allowed us to obtain a first list of native plant nurseries and the species they cultivate. Finally, some aspects are proposed in order to strengthen this network of actors and thus be able to fulfill the restoration initiatives of the country.Centro de Investigación y Desarrollo Tecnológico para la Agricultura FamiliarFil: Lacoretz, Mariela V. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución. Laboratorio de Ecología Funcional; ArgentinaFil: Lacoretz, Mariela V. Universidad de Buenos Aires. Instituto de Ecología, Genética y Evolución de Buenos Aires; ArgentinaFil: Lacoretz, Mariela V. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ecología, Genética y Evolución de Buenos Aires; ArgentinaFil: Villanova, Ingrid. Instituto Nacional de Tecnología Agropecuaria (INTA). Centro de Investigación y Desarrollo Tecnológico para la Agricultura Familiar; ArgentinaFil: Sanchez, Marcela Ines. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Biológicos; ArgentinaFil: Verrastro, España. Universidad Nacional de San Martín. Secretaría de Extensión. Coordinación de Programas Socioambientales; ArgentinaFil: Cristiano, Piedad María. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución. Laboratorio de Ecología Funcional; ArgentinaFil: Cristiano, Piedad María. Universidad de Buenos Aires. Instituto de Ecología, Genética y Evolución de Buenos Aires; ArgentinaFil: Cristiano, Piedad María. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentin

Characterization of native plant nurseries and their possible contribution to the restoration of the talares of Buenos Aires

The talares represent the main native forest of the Buenos Aires province; however, they are in danger. Given their extreme vulnerability, it is not only necessary to promote their conservation, but also their restoration. The native plant nurseries represent a key link in restoration projects. In this work, the first survey of native plant nurseries in the distribution area of talares of Buenos Aires was carried out to characterize and evaluate them as possible restoration nodes. During 2019, surveys to these nurseries were carried out either in person or online. More than 70% of the nurseries were concentrated in the Buenos Aires Metropolitan Area and their objectives comprise commercialization, conservation/restoration or education. More than 60% of the nurseries were less than 5 years old and less than 500 m2 in size, and they do not control humidity, temperature and/or light; however, they have greenhouses. These characteristics seem to reflect an increase in society’s interest on native plants in recent years, which would have led to the development of new nurseries at small scale. The main plant species of the talares were cultivated in these nurseries, so they could be very important actors when planning restoration projects of these forests. We emphasize the importance of consolidating a network of collaboration between nurseries, scientists, protected areas, and government agencies in order to restore this ecosystem. In this way, it is necessary to expand the scope of this study in order to know the native plant nurseries in the rest of the country, associated with other endangered ecosystems, and to be able to evaluate if Argentina is in a position to meet its internal goals and international restoration commitments. We hope that the results of this work will promote joint collaborations to restore the talares of Buenos Aires and other ecosystems in Argentina.Fil: Lacoretz, Mariela Verónica. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; ArgentinaFil: Malavert Pineda, Cristian Jonatan. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Producción Vegetal. Cátedra de Cultivos Industriales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Rolandi, Carmen. Feriado al Planeta; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Zilli, Cecilia. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; ArgentinaFil: Madanes, Nora. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; ArgentinaFil: Cristiano, Piedad María. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentin

Primary productivity estimation by efficiency model and remote sensing

Uno de los modelos más utilizados para estimar la Productividad Primaria Neta (PPN) a escala regional es el de eficiencias de Kumar and Monteith que permite la inclusión de información satelital. Uno de los parámetros clave es la eficiencia en su utilización (EUR), afectado por los factores de estrés. El objetivo fue mejorar las estimaciones a escala regional de la PPN en pastizales, bajo distintas condiciones de estrés proponiendo una cartografía temática de EUR para la región pampeana, teniendo en cuenta los factores de estrés predominantes (hídrico y nutricional). A través de ensayos manipulativos, se determinaron los cambios en la EUR en 4 gramíneas y en una pastura multiespecífica donde se incluyó el efecto del pastoreo. Para regionalizar los resultados, se generó una cartografía temática de las condiciones hídricas y nutricionales de la región. Para validar este mapa se estimó la PPNA mensual y anual utilizando imágenes MODIS que se compararon con datos de PPNA estimados a campo y con los resultados de otros dos modelos comúnmente utilizados. En los ensayos monoespecíficos la EUR varió entre 2.3-5.2 g/MJ bajo condiciones óptimas de crecimiento y entre 1.02-1.75 g/MJ en las plantas con estrés. En el ensayo multiespecífico, la EUR varió entre 0.63-1.94 g/MJ. La PPNA estimada anual presentó los menores valores en el suroeste de la región (menor a 5800 kg/ha.año) y fue aumentando hacia el noreste hasta alcanzar valores de 14500 kg/ha.año. La validación con datos de PPNA observados y estimados por otros modelos indican que nuestro modelo de EUR variable presenta mayor nivel de ajuste que el de EUR fija.One of the most commonly models used to estimate net primary productivity (NPP) at regional level is that of Kumar and Monteith efficiencies that allows the inclusion of satellite information. One of the key parameters is the radiation use efficiency (RUE), affected by different stresses. The aim was to improve regional estimates of NPP in grasslands under different stress conditions suggesting a thematic mapping of RUE for the Pampas region, taking into account the prevailing factors of stress (water and nutrition). Through manipulative experiments, changes in the EUR were identified in 4 grasses and a multispecies pasture where the effect of grazing was included. To regionalize these results, we generated a thematic mapping of water and nutritional conditions of the region. To validate this map, the monthly and annual aerial NPP (ANPP) was estimated using MODIS images. Data were compared with ANPP from field data and the results of two other commonly used models. In monospecific experiments, RUE ranged from 2.3-5.2 g/MJ under optimal growth conditions and between 1.02-1.75 g/MJ in plants under stress. In the multispecies experiment, the RUE varied between 0.63-1.94 g/MJ. The estimated annual PPNA presented the lowest values in the southwestern region (minor than 5800 kg/ha.year) and was increasing towards the northeast to reach values of 14,500 kg/ha.year. The validation results indicate that our variable RUE model presents adjustment higher than the fixed RUE model.Fil:Cristiano, Piedad María. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Total and aboveground radiation use efficiency in C3 and C4 grass species influenced by nitrogen and water availability

Absorbed solar radiation and radiation use efficiency (RUE) can be used to estimate net primary productivity of terrestrial ecosystems. In ecosystems dominated by grasses, belowground productivity cannot be neglected in terms of carbon balance because of the high proportion of biomass allocated to roots. The objective of this study was to quantify total RUE (tRUE), which includes both below and aboveground biomass of two C3 (Lolium perenne and Dactylis glomerata) and one C4 (Cynodon dactylon) grass species, under four treatments with contrasting water and nitrogen availabilities. The ratios between tRUE and aboveground RUE (aRUE) for species and treatments were analyzed. The tRUE was calculated from measurements of incoming photosynthetically active radiation (PAR), the fraction of PAR intercepted and shoots and roots productivity in pot experiments. The highest tRUE values in the three species were found in the treatment without growth limitations (4.32–6.93 g MJ−1), while the lowest tRUE values were observed under water and nutrient deficits conditions (2.62–2.85 g MJ−1). Contrary to predictions from the optimization theory, one of the C3 grass species allocated relatively high biomass to the roots when water availability was high while for the C4 grass species the shoot:root ratios and the root mass fraction did not change under resource limitation conditions compared to ample resource availability. tRUE exhibited small changes in the C4 species with variations in resource availability while it did decrease substantially for the C3 species when at least one of the resources was limited. These results highlight belowground biomass importance in calculating RUE of grasses.Instituto de Clima y AguaFil: Cristiano, Piedad María. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución. Laboratorio de Ecología Funcional; ArgentinaFil: Posse Beaulieu, Gabriela. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Clima y Agua; ArgentinaFil: Di Bella, Carlos Marcelo. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Clima y Agua; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Métodos Cuantitativos y Sistemas de Información; Argentin

Carbon and water vapor balance in a subtropical pine plantation

Afforestation has been proposed as an effective tool for protecting primary and/or secondary forests and for mitigating atmospheric CO2. However, the dynamics of primary productivity differs between plantations and natural forests. The objective of this work was to evaluate the potential for carbon storage of a commercial pine plantation by determining its carbon balance. Measurements started when trees were aged 6 and ended when they were older than 8 years. We measured CO2 and water vapor concentrations using the Eddy covariance method. Gross primary productivity in 2010 and 2011 was 4290 ± 473 g C m-2 and 4015 ± 485 g C m-2, respectively. Ecosystem respiration ranged between 7 and 20 g C m-2 d-1, reaching peaks in all Februaries. Of the 30 months monitored, the plantation acted as carbon source for 21 months and as carbon sink for 6 months, while values close to neutrality were obtained during 3 months. The positive balance representing CO2 loss by the system was most likely due to the cut branches left on the ground following pruning activities. The plantation was subjected to pruning in January and September 2008 and to sanitary pruning in October 2010. In all cases, cut branches were not removed but remained on the ground. Residue management seems to have a very important impact on carbon balance.Fil: Posse Beaulieu, Gabriela. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación de Recursos Naturales. Instituto de Clima y Agua; ArgentinaFil: Lewczuk, Nuria. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación de Recursos Naturales. Instituto de Clima y Agua; ArgentinaFil: Richter, Klaus. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación de Recursos Naturales. Instituto de Clima y Agua; ArgentinaFil: Cristiano, Piedad María. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentin

Seed bank composition and Ligustrum lucidum invasion in coastal forests in Buenos Aires, Argentina

El banco de semillas es un componente clave de los ecosistemas terrestres ya que determina el desarrollo futuro de la estructura y composición de sus plantas vasculares. En ambientes disturbados, el banco de semillas puede favorecer la regeneración de las especies nativas o la colonización y expansión de especies exóticas. Los bosques dominados por Celtis tala constituyen la principal comunidad boscosa de la provincia de Buenos Aires (Argentina) y han experimentado fuertes perturbaciones antrópicas, convirtiéndose en susceptibles a la invasión por la especie exótica Ligustrum lucidum (ligustro). El objetivo del trabajo fue estudiar la composición del banco de semillas de los bosques de tala de la Reserva "El Destino" (Magdalena, Buenos Aires), su relación con la vegetación y distintas propiedades del suelo en áreas con distinto grado de invasión. Se establecieron cinco parcelas en dos cordones boscosos que abarcaron cuatro tipos de bosques (conservado, semi-conservado, ligustral e implantado) de donde se tomaron muestras de suelo y se relevó la vegetación. Se analizó cualitativa y cuantitativamente la composición del banco de semillas durante cuatro meses en el invernadero de Ciudad Universitaria de la Universidad de Buenos Aires. Los bosques invadidos se caracterizaron por presentar menor diversidad, riqueza y equitatividad que el resto de los bosques. Los bancos de semilla de los bosques conservado y semi-conservado presentaron mayor proporción de especies herbáceas mientras que en los bosques invadidos dominó L. lucidum. Estos resultados sugieren que el grado de invasión ha superado el umbral de irreversibilidad, consolidándose como neoecosistemas dominados por L. lucidum.Seed banks are key components of terrestrial ecosystems as they determine the future development of its vascular plants. In disturbed environments, seed banks can either favor regeneration of native species, or enhance colonization and expansion of exotic species. In Buenos Aires Province (Argentina), Celtis tala forests are the main wooded community. They have experienced strong anthropogenic disturbances that made them vulnerable to invasion from the exotic tree Ligustrum lucidum. The objective of this work was to study the seed bank composition in Celtis tala forests in "El Destino" Reserve (Magdalena, Buenos Aires) and its relation with the standing vegetation in areas with distinct degrees of invasion. Five plots were stablished in two wooded cordons, covering four types of environments. In each plot, a soil sample was taken and standing vegetation was studied. Seed bank composition was analyzed qualitatively and quantitatively during four months in a Ciudad Universitaria's greenhouse. Invaded environments were characterized by having less diversity, richness and evenness than those presented by non-invaded environments. Non-invaded environment's seed banks exhibited a larger proportion of herbaceous species while in invaded seed banks, Ligusrtrum lucidum dominated. This result shows that invasion has exceeded the threshold of reversibility, consolidating as neo-ecosystems dominated by L. lucidum.Fil: Diaz Villa, Maria Virginia Eva. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; ArgentinaFil: Madanes, Nora. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; ArgentinaFil: Cristiano, Piedad María. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; ArgentinaFil: Goldstein, Guillermo Hernan. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentin

Climatic determinants of photosynthetic activity in humid subtropical forests under different forestry activities

Forests are key ecosystems providing a variety of contributions to societies that are based on the ecological processes occurring in them. Understanding the relationship between ecological processes and the climate system is essential to predict how they will respond to possible future climatic conditions and trajectories. In this study, the relationship between climate variables and vegetation dynamics was studied in different plots of preserved native forest, selectively logged forests, and pine plantations in an area of humid subtropical forest in Misiones, Argentina. Time series analysis via gaussian processes and multiple regressions with the moving average of explanatory variables combined with Bayesian model selection using the lowest Bayesian Information Index as selection criteria were used to determine the relationship between the Enhanced Vegetation Index (EVI) and meteorological variables including temperature, rainfall, global radiation, and potential evapotranspiration. Our results showed that EVI's variability is best explained by a combination of the moving average of temperature, global radiation, and the logarithm of potential evapotranspiration. The estimated EVI value is the minimum predicted value of each linear function of these variables, indicating that these ecosystems are conditioned by the most limiting meteorological variable for vegetation growth at each time among potential evapotranspiration, global radiation, and temperature, but not by a linear combination of these. The different ecosystems, in turn, responded differently to climatic variables. Both logged forests and pine plantations exhibited near-zero slopes with both global radiation and temperature, indicating they are close to temperature and radiation saturation points. Moreover, they presented a higher sensitivity to these variables than preserved forests that were more sensitive to atmospheric water demand. The proposed methodology allowed us to separate the external climatic influence in the forest photosynthetic activity from the internal vegetation processes. Moreover, the final model was capable to capture the multi-scale temporal patterns of forest vegetation.Fil: Diaz Villa, Maria Virginia Eva. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución. Laboratorio de Ecología Funcional; ArgentinaFil: Bruzzone, Octavio Augusto. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Patagonia Norte. Estación Experimental Agropecuaria San Carlos de Bariloche. Instituto de Investigaciones Forestales y Agropecuarias Bariloche. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones Forestales y Agropecuarias Bariloche; ArgentinaFil: Goldstein, Guillermo Hernan. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución. Laboratorio de Ecología Funcional; Argentina. University of Miami; Estados UnidosFil: Cristiano, Piedad María. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución. Laboratorio de Ecología Funcional; Argentin