The coupling of South American soybean and cattle production frontiers: new challenges for conservation policy and land change science

Different drivers and places of land use change in South America have often been studied in isolation. Evidence suggests, however, that in many instances, both places and drivers are becoming increasingly interconnected. The growing diversification and internationalization of agricultural commodity chains is creating new linkages across production frontiers and sectors that have important implications for conservation. In this article, we explore the implications of the sectoral and geographical coupling of soybean and cattle production frontiers for forest conservation in South America, with particular attention to the potential for policy-induced deforestation leakage. We conclude that the existence of coupled frontiers creates a need for more actor-centered approaches to conservation policy and research.Fil: Gasparri, Nestor Ignacio. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto de Ecología Regional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán; ArgentinaFil: Le Polain de Waroux, Yann. University Of Stanford; Estados Unido

Agents of Forest Disturbance in the Argentine Dry Chaco

Forest degradation in the tropics is a widespread, yet poorly understood phenomenon. This is particularly true for tropical and subtropical dry forests, where a variety of disturbances, both natural and anthropogenic, affect forest canopies. Addressing forest degradation thus requires a spatially-explicit understanding of the causes of disturbances. Here, we apply an approach for attributing agents of forest disturbance across large areas of tropical dry forests, based on the Landsat image time series. Focusing on the 489,000 km2 Argentine Dry Chaco, we derived metrics on the spectral characteristics and shape of disturbance patches. We then used these metrics in a random forests classification framework to estimate the area of logging, fire, partial clearing, riparian changes and drought. Our results highlight that partial clearing was the most widespread type of forest disturbance from 1990–to 2017, extending over 5520 km2 (±407 km2), followed by fire (4562 ± 388 km2) and logging (3891 ± 341 km2). Our analyses also reveal marked trends over time, with partial clearing generally becoming more prevalent, whereas fires declined. Comparing the spatial patterns of different disturbance types against accessibility indicators showed that fire and logging prevalence was higher closer to fields, while smallholder homesteads were associated with less burning. Roads were, surprisingly, not associated with clear trends in disturbance prevalence. To our knowledge, this is the first attribution of disturbance agents in tropical dry forests based on satellite-based indicators. While our study reveals remaining uncertainties in this attribution process, our framework has considerable potential for monitoring tropical dry forest disturbances at scale. Tropical dry forests in South America, Africa and Southeast Asia are some of the fastest disappearing ecosystems on the planet, and more robust monitoring of forest degradation in these regions is urgently needed.Peer Reviewe

Structural changes caused by selective logging in Montane Forest of northern Salta, Argentina

Se compararon los parámetros estructurales de dos rodales sometidos a dinámica natural con los de otro que fue aprovechado mediante tala selectiva 15 años atrás en Bosques Montanos del norte de la provincia de Salta, Argentina. Se realizó un muestreo areal sistemático considerando tres categorías de tamaño: individuos mayores (DAP >10 cm), brinzales (DAP 1.3 m) y renovales (altura 10 cm), saplings (DBH 1.3 m), and seedlings (height <1.3 m). The density of adults, saplings and seedlings, and basal area for adults, were calculated for each stand. Logs of the main commercial species (Cedrela lilloi, Juglans australis and Podocarpus parlatorei) were classified into timber use categories. We compared structural parameters of stands by using descriptive statistics. In each plot a hemispherical photograph was taken to estimate canopy cover. Stand basal area was lower in the harvested stand, while we found no important differences in density. At the species level, a significant decrease in basal area was found for Podocarpus parlatorei. Cedrela lilloi regeneration was lower in the logged stand than in natural stands with frequent gaps. Timber values of previously harvested stands are depleted with no regeneration of commercial species. Thus, these forests cannot yield new harvests if the current condition, especially if selective cuttings without silviculture practice after logging, persists. We therefore conclude that silvicultural interventions are needed after selective logging to maintain the commercial timber species. The current management is not sustainable because it does not ensure adequate opportunities for natural regeneration.Facultad de Ciencias Agrarias y ForestalesUniversidad Nacional de Tucumá

Structural changes caused by selective logging in Montane Forest of northern Salta, Argentina

Se compararon los parámetros estructurales de dos rodales sometidos a dinámica natural con los de otro que fue aprovechado mediante tala selectiva 15 años atrás en Bosques Montanos del norte de la provincia de Salta, Argentina. Se realizó un muestreo areal sistemático considerando tres categorías de tamaño: individuos mayores (DAP >10 cm), brinzales (DAP 1.3 m) y renovales (altura 10 cm), saplings (DBH 1.3 m), and seedlings (height <1.3 m). The density of adults, saplings and seedlings, and basal area for adults, were calculated for each stand. Logs of the main commercial species (Cedrela lilloi, Juglans australis and Podocarpus parlatorei) were classified into timber use categories. We compared structural parameters of stands by using descriptive statistics. In each plot a hemispherical photograph was taken to estimate canopy cover. Stand basal area was lower in the harvested stand, while we found no important differences in density. At the species level, a significant decrease in basal area was found for Podocarpus parlatorei. Cedrela lilloi regeneration was lower in the logged stand than in natural stands with frequent gaps. Timber values of previously harvested stands are depleted with no regeneration of commercial species. Thus, these forests cannot yield new harvests if the current condition, especially if selective cuttings without silviculture practice after logging, persists. We therefore conclude that silvicultural interventions are needed after selective logging to maintain the commercial timber species. The current management is not sustainable because it does not ensure adequate opportunities for natural regeneration.Facultad de Ciencias Agrarias y ForestalesUniversidad Nacional de Tucumá

Estructura y dinámica de bosques de palo santo en el Chaco Seco

El conocimiento de la estructura y la dinámica de las poblaciones de Bulnesia sarmientoi ("palo santo") es necesario para una gestión forestal capaz de conservar la especie, asegurar la producción maderera de alta calidad y preservar los servicios ecosistémicos que brindan los bosques donde se encuentra. Se caracterizó la estructura y la dinámica forestal en bosques con presencia de palo santo en el norte del Chaco Seco argentino. Se establecieron 21 conglomerados compuestos cada uno por cuatro juegos de parcelas concéntricas de 1000 m² (diámetro >20 cm) y 500 m² (diámetro >10 cm), ubicadas en los vértices de un cuadrado de 100 m de lado. Los conglomerados se midieron en 2007 y 2012. Se realizaron cálculos de parámetros estructurales y del índice devalor de importancia de cada especie en cada conglomerado. Se hallaron tres estructuras típicas: a) palosantales de bañado, b) palo cruz con palo santo, y c) bosque chaqueño con presencia de palo santo. A partir de la remediciónde los árboles de palo santo se calculó un incremento periódico anual de 1.14 mm/año. Tomando como referencia la estructura de un conglomerado con palo santo que fue aprovechado entre mediciones se realizaron simulaciones de intervenciones alternativas (remoción de 80% de individuos de todas las clasesdiamétricas o aplicación de restricción de diámetro >40 cm) sobre la dinámica del rodal. Las proyecciones a 50 años muestran que la corta de 80% es muy severa, lo que indicaría que los aprovechamientos de tamaños menores para postes pueden comprometer la recuperación del rodal. En las cortas centradas en los tamaños mayores se lograría una recuperación en 50 años. En función de nuestros resultados, se sugiere un enfoque de uso de la especie centrado en productos de gran tamaño y con el mayor valor agregado posible.Structure and dynamics of palo santo forests in the Dry Chaco. Knowledge on the structure and dynamics of Bulnesia sarmientoi (“palo santo”) populations is necessary for forest management aimed at the conservation and high-quality timber production by this species and the preservation of the ecosystem services of its forests. We characterized forest structure and dynamics in stands with palo santo presence in the Nothern Argentinian Dry Chaco. We sampled 21 forest sampling clusters. Each forest sampling cluster includes four sets of concentric circular plots of 1000 m² (diameter >20 cm) and 500 m² (diameter >10 cm), located at the vertices of a square of 100 m side. Forest clusters were measured in 2007 and 2012. We calculated the importance value index (IVI) of each species in each conglomerate. We identified three typical structures with palo santo: a) palosantales in regularly flooded soils, b) palo cruz con palo santo, and c) Chaco mixed forest with the presence of palo santo. Periodic annual increment in diameter was 1.14 mm for all diameter classes. Taking as a reference the structure of a conglomerate with palo santo that was selective logged, we simulated alternative interventions (80% removal of all diameter classes or a diameter restriction of >40 cm) on stand dynamics. Cutting of 80% of the trees was a very severe intervention, suggesting that the removal of the smallest sizes for rural construction could compromise the recovery of the stand. A minimum size restriction could warrant recovery in 50 years. We suggest that the harvest of palo santo trees should be focused on large individuals with the highest added value potential.Fil: Loto, Dante Ernesto. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo; ArgentinaFil: Gasparri, Nestor Ignacio. Universidad Nacional de Tucumán. Instituto de Ecología Regional. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Ecología Regional; ArgentinaFil: Azcona, Maximiliano. Ministerio de Ambiente y Desarrollo Sustentable de la Nación; ArgentinaFil: Garcia, Santiago. Ministerio de Ambiente y Desarrollo Sustentable de la Nación; ArgentinaFil: Spagarino, Carlos. Parque Nacional Río Pilcomayo; Argentin

Structural changes caused by selective logging in Montane Forest of northern Salta, Argentina

Se compararon los parámetros estructurales de dos rodales sometidos a dinámica natural con los de otro que fue aprovechado mediante tala selectiva 15 años atrás en Bosques Montanos del norte de la provincia de Salta, Argentina. Se realizó un muestreo areal sistemático considerando tres categorías de tamaño: individuos mayores (DAP >10 cm), brinzales (DAP 1.3 m) y renovales (altura 10 cm), saplings (DBH 1.3 m), and seedlings (height <1.3 m). The density of adults, saplings and seedlings, and basal area for adults, were calculated for each stand. Logs of the main commercial species (Cedrela lilloi, Juglans australis and Podocarpus parlatorei) were classified into timber use categories. We compared structural parameters of stands by using descriptive statistics. In each plot a hemispherical photograph was taken to estimate canopy cover. Stand basal area was lower in the harvested stand, while we found no important differences in density. At the species level, a significant decrease in basal area was found for Podocarpus parlatorei. Cedrela lilloi regeneration was lower in the logged stand than in natural stands with frequent gaps. Timber values of previously harvested stands are depleted with no regeneration of commercial species. Thus, these forests cannot yield new harvests if the current condition, especially if selective cuttings without silviculture practice after logging, persists. We therefore conclude that silvicultural interventions are needed after selective logging to maintain the commercial timber species. The current management is not sustainable because it does not ensure adequate opportunities for natural regeneration

Differences in production, carbon stocks and biodiversity outcomes of land tenure regimes in the Argentine Dry Chaco

Rising global demand for agricultural products results in agricultural expansion and intensification, with substantial environmental trade-offs. The South American Dry Chaco contains some of the fastest expanding agricultural frontiers worldwide, and includes diverse forms of land management, mainly associated with different land tenure regimes; which in turn are segregated along environmental gradients (mostly rainfall). Yet, how these regimes impact the environment and how trade-offs between production and environmental outcomes varies remains poorly understood. Here, we assessed how biodiversity, biomass stocks, and agricultural production, measured in meat-equivalents, differ among land tenure regimes in the Dry Chaco. We calculated a land-use outcome index (LUO) that combines indices comparing actual vs. potential values of 'preservation of biodiversity' (PI), 'standing biomass' (BI) and 'meat production' (MI). We found land-use outcomes to vary substantially among land-tenure regimes. Protected areas showed a biodiversity index of 0.75, similar to that of large and medium-sized farms (0.72 in both farming systems), and higher than in the other tenure regimes. Biomass index was similar among land tenure regimes, whereas we found the highest median meat production index on indigenous lands (MI = 0.35). Land-use outcomes, however, varied more across different environmental conditions than across land tenure regimes. Our results suggest that in the Argentine Dry Chaco, there is no single land tenure regime that better minimizes the trade-offs between production and environmental outcomes. A useful approach to manage these trade-offs would be to develop geographically explicit guidelines for land-use zoning, identifying the land tenure regimes more appropriate for each zone.Environmental Conservation Found of the Argentina Galicia BankEinstein Stiftung Berlin 10.13039/501100006188The German Federal Ministry of Education and ScienceGerman Research FoundationArgentina National Agency of Science and Technological ResearchRufford Foundation 10.13039/100007463Consejo Nacional de Investigaciones Científicas y Técnicas 10.13039/501100002923Peer Reviewe

Characterization of forest carbon stocks at the landscape scale in the Argentine Dry Chaco

One of the most proposed climate change mitigation strategies is carbon sequestration by vegetation. This depends on the rate of carbon uptake and transformation in biomass, the rate of release through respiration, and the stability of the stocks to disturbances. Forest diversity influences these factors, in a degree that varies according to certain functional characteristics. The Dry Chaco is the largest dry forest in the world, and one of the regions with the highest deforestation rates of the planet. Our aim was to geographically describe three carbon stock attributes from forest communities of the Dry Chaco Forests in Argentina at the landscape scale: wood density, tree height and annual carbon increase in aboveground biomass, as proxies of forest stability and carbon long-term persistence. In addition, we evaluated the relationships between these attributes and climate features, in the search of potential climate controls. Higher precipitation during the growing season and low mean annual temperature benefited the combination of these three treats related to C storage persistence. The distribution of the most favorable states of the three attributes is centered at the northwestern area of the Dry Chaco. Our geographic description of carbon stocks attributes can contribute to more suitable conservation planning and allows forecasting potential shifts in forests due to climate change.Fil: Powell, Priscila Ana. Universidad Nacional de Tucumán. Instituto de Ecología Regional. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Ecología Regional; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Cátedra de Ecología General; ArgentinaFil: Nanni, Ana Sofía. Universidad Nacional de Tucumán. Instituto de Ecología Regional. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Ecología Regional; ArgentinaFil: Nazaro, María Gabriela. Universidad Nacional de Tucumán. Instituto de Ecología Regional. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Ecología Regional; ArgentinaFil: Loto, Dante Ernesto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia de Santiago del Estero. Universidad Nacional de Santiago del Estero. Centro de Investigaciones y Transferencia de Santiago del Estero; Argentina. Universidad Nacional de Santiago del Estero. Facultad de Ciencias Forestales. Instituto de Silvicultura y Manejo de Bosques; ArgentinaFil: Torres, Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Museo de Zoología; ArgentinaFil: Gasparri, Nestor Ignacio. Universidad Nacional de Tucumán. Instituto de Ecología Regional. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Ecología Regional; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo; Argentin

Structure and dynamics of palo santo forests in the Dry Chaco

El conocimiento de la estructura y la dinámica de las poblaciones de Bulnesia sarmientoi ("palo santo") es necesario para una gestión forestal capaz de conservar la especie, asegurar la producción maderera de alta calidad y preservar los servicios ecosistémicos que brindan los bosques donde se encuentra. Se caracterizó la estructura y la dinámica forestal en bosques con presencia de palo santo en el norte del Chaco Seco argentino. Se establecieron 21 conglomerados compuestos cada uno por cuatro juegos de parcelas concéntricas de 1000 m² (diámetro >20 cm) y 500 m² (diámetro >10 cm), ubicadas en los vértices de un cuadrado de 100 m de lado. Los conglomerados se midieron en 2007 y 2012. Se realizaron cálculos de parámetros estructurales y del índice de valor de importancia de cada especie en cada conglomerado. Se hallaron tres estructuras típicas: a) palosantales de bañado, b) palo cruz con palo santo, y c) bosque chaqueño con presencia de palo santo. A partir de la remedición de los árboles de palo santo se calculó un incremento periódico anual de 1.14 mm/año. Tomando como referencia la estructura de un conglomerado con palo santo que fue aprovechado entre mediciones se realizaron simulaciones de intervenciones alternativas (remoción de 80% de individuos de todas las clases diamétricas o aplicación de restricción de diámetro >40 cm) sobre la dinámica del rodal. Las proyecciones a 50 años muestran que la corta de 80% es muy severa, lo que indicaría que los aprovechamientos de tamaños menores para postes pueden comprometer la recuperación del rodal. En las cortas centradas en los tamaños mayores se lograría una recuperación en 50 años. En función de nuestros resultados, se sugiere un enfoque de uso de la especie centrado en productos de gran tamaño y con el mayor valor agregado posible.Knowledge on the structure and dynamics of Bulnesia sarmientoi (“palo santo”) populations is necessary for forest management aimed at the conservation and high-quality timber production by this species and the preservation of the ecosystem services of its forests. We characterized forest structure and dynamics in stands with palo santo presence in the Nothern Argentinian Dry Chaco. We sampled 21 forest sampling clusters. Each forest sampling cluster includes four sets of concentric circular plots of 1000 m² (diameter >20 cm) and 500 m² (diameter >10 cm), located at the vertices of a square of 100 m side. Forest clusters were measured in 2007 and 2012. We calculated the importance value index (IVI) of each species in each conglomerate. We identified three typical structures with palo santo: a) palosantales in regularly flooded soils, b) palo cruz con palo santo, and c) Chaco mixed forest with the presence of palo santo. Periodic annual increment in diameter was 1.14 mm for all diameter classes. Taking as a reference the structure of a conglomerate with palo santo that was selective logged, we simulated alternative interventions (80% removal of all diameter classes or a diameter restriction of >40 cm) on stand dynamics. Cutting of 80% of the trees was a very severe intervention, suggesting that the removal of the smallest sizes for rural construction could compromise the recovery of the stand. A minimum size restriction could warrant recovery in 50 years. We suggest that the harvest of palo santo trees should be focused on large individuals with the highest added value potential