- Unidad de Investigación en Bosque Nativo de la ESTACIÓN FORESTAL INTA-VILLA DOLORES
Camino Viejo a San José (km 1), (5.870) Villa Dolores (Traslasierra) Córdoba-ARGENTINA.
www.inta.gob.ar/personas/lopez.dardor - (54)-3544- 420154
- Doctor en Biología (Área: Ecología)- Centro Universitario Bariloche, Universidad Nacional del Comahue, pcia. Río Negr... moreDoctor en Biología (Área: Ecología)- Centro Universitario Bariloche, Universidad Nacional del Comahue, pcia. Río Negro, Argentina.Ingeniero Agrónomo- Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, pcia. Santa Fe, Argentina.Ingresó al Instituto Nacional de Tecnología Agropecuaria (INTA) en noviembre 2004:Desde diciembre 2014, a la actualidad, se desarrolla como Investigador-INTA en la Estación Forestal INTA- Villa Dolores (unidad de la EEA Manfredi). Trabaja en ecología y manejo de ecosistemas terrestres del Chaco Seco y Chaco Serrano. Desde agosto 2008 a noviembre 2014 trabajó como Investigador en el Área de Recursos Naturales del INTA-EEA Bariloche. Entre noviembre 2004 - julio 2008 se desarrolló como Becario INTA en el Área de Recursos Naturales (INTA-EEA Bariloche), trabajando en el tema de evaluación y monitoreo de la Desertificación en Patagonia.Otros cargos:- Desde abril 2014 (a la actualidad) es miembro del plantel docente de la Maestría en Producción de Rumiantes Menores (http://inta.gob.ar/documentos/maestria-produccion-rumiantes-menores).- Entre abril 2001 y octubre 2004 fue ayudante de la Cátedra de Ecología General de la Facultad de Ciencias Agrarias- UNR (Argentina). Trabajó en proyectos de investigación asociados a la ecología de los bosques de la “Cuña Boscosa Santafesina (Ecorregión del Chaco Húmedo)”.Sus líneas temáticas de trabajo se relacionan con: -Ecología de comunidades y de paisaje en ecosistemas áridos y semiáridos.-Modelo de Estados y Transiciones, Umbrales, Resiliencia ecológica (resistencia) de ecosistemas.-Evaluación y Monitoreo de la Desertificación.-Recuperación y Restauración Ecológica.–Genética ecológica de especies forrajeras nativas.-Sustentabilidad y Resiliencia en Sistemas Socio-Ecológicos.edit
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Plants show different morphologies when growing in different habitats, but they also vary in their morphology with plant size. We examined differences in sun‐ and shade‐grown plants of the bromeliad Aechmea distichantha with respect to... more
Plants show different morphologies when growing in different habitats, but they also vary in their morphology with plant size. We examined differences in sun‐ and shade‐grown plants of the bromeliad Aechmea distichantha with respect to relationships between plant size and variables related to plant architecture, biomass allocation and tank water dynamics. We selected vegetative plants from the understorey and from forest edges of a Chaco forest, encompassing the whole size range of this bromeliad. Plant biomass was positively correlated with most architectural variables and negatively correlated with most biomass allocation variables. Understorey plants were taller and had larger diameters, whereas sun plants had more leaves, larger sheath area, sheath biomass and sheath mass fraction. All tank water‐related variables were positively correlated with plant biomass. Understorey plants had a greater projected leaf area, whereas sun plants had higher water content and evaporative area. ...
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Dealing with complex challenges worldwide regarding sustainable rural development requires applied frameworks to understand and manage change in complex social-ecological systems. The sustainable livelihood approach is a framework for... more
Dealing with complex challenges worldwide regarding sustainable rural development requires applied frameworks to understand and manage change in complex social-ecological systems. The sustainable livelihood approach is a framework for thinking and communicating about factors that impact on the livelihoods of rural families from a multidimensional perspective, including wellbeing, health, income, social networks and the local environment. It is designed to assist in identifying changes or transformations that can be performed to institutions, assets or strategies of rural families in order to promote adaptive capacities and resilience to local communities. However, operative tools in order to implement these concepts in a systematic way are still challenging. In this regard, we argue that the State-and-Transition Model provides a useful perspective, and a conceptual basis for theory and disciplinary integration that could provide a dynamic perspective not only for rangeland managemen...
The sustainable management of agroforestry landscapes is complex because they are socio-ecosystems that integrate biological and socio-productive diversity with spatial-temporal dynamical interactions. Furthermore, agroforestry landscapes... more
The sustainable management of agroforestry landscapes is complex because they are socio-ecosystems that integrate biological and socio-productive diversity with spatial-temporal dynamical interactions. Furthermore, agroforestry landscapes provide a variety of ecosystem goods and services at both the farm and global levels, and host thousands of rural people whose livelihoods depend on the forest. Strong dependence on the forest for subsistence strengthens the need to promote their sustainable management. In this chapter, we propose that management practices of Social-Ecological Systems (SES) should be addressed at the landscape scale using a resilience approach to reduce the vulnerability of agroforestry systems to environmental and/or anthropogenic drivers. We examine key properties of farm-level SES components; we demonstrate how they collectively interconnect at the landscape scale and analyze the benefits of resolving social-ecological conflicts at the landscape scale. We highlight a case study in which social-environmental conflicts are increasingly frequent and demonstrate that a resilience management approach at the landscape level should be used as a tool for resolving conflicts. Finally, we conclude that as the search for solutions through decision-making at the farm scale may have indirect and unexpected effects on other SES at the landscape level, replacing a farm-scale perspective with a landscape-scale perspective could increase SES-resilience, reducing their vulnerability to different drivers.
Research Interests: Business and Agroforestry
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The sustainable management of agroforestry landscapes is complex because they are socio-ecosystems that integrate biological and socio-productive diversity with spatial-temporal dynamical interactions. Furthermore, agroforestry landscapes... more
The sustainable management of agroforestry landscapes is complex because they are socio-ecosystems that integrate biological and socio-productive diversity with spatial-temporal dynamical interactions. Furthermore, agroforestry landscapes provide a variety of ecosystem goods and services at both the farm and global levels, and host thousands of rural people whose livelihoods depend on the forest. Strong dependence on the forest for subsistence strengthens the need to promote their sustainable management. In this chapter, we propose that management practices of Social-Ecological Systems (SES) should be addressed at the landscape scale using a resilience approach to reduce the vulnerability of agroforestry systems to environmental and/or anthropogenic drivers. We examine key properties of farm-level SES components; we demonstrate how they collectively interconnect at the landscape scale and analyze the benefits of resolving social-ecological conflicts at the landscape scale. We highli...
Research Interests: Business and Agroforestry
ABSTRACT Una herramienta para monitorear sequías en regiones áridas y semiáridas de Patagonia Norte Una herramienta para monitorear sequías en regiones áridas y semiáridas de Patagonia Norte RESUMEN La variabilidad ambiental es una... more
ABSTRACT Una herramienta para monitorear sequías en regiones áridas y semiáridas de Patagonia Norte Una herramienta para monitorear sequías en regiones áridas y semiáridas de Patagonia Norte RESUMEN La variabilidad ambiental es una característica de regiones pastoriles áridas y semiáridas, siendo la sequía uno de los principales problemas en sistemas ganaderos extensivos, con implicancias productivas y económi-cas tanto a escala predial como regional. El monitoreo regional de los procesos de sequía es una herramienta fundamental y necesaria, como complemento de propuestas y manejos adaptativos activos que busquen miti-gar los impactos sobre la producción. En el presente artículo proponemos una herramienta para el monitoreo de sequías en zonas áridas y semiáridas, basada en datos provistos por sensores remotos. El objetivo fue desarrollar un sistema de monitoreo basado en un índice espectral, desagregando la heterogeneidad biofísi-ca regional en unidades homogéneas, y relacionándola con los momentos clave de decisiones asociadas al manejo ganadero tradicional, en sistemas de producción ovina de Patagonia Norte. Esta integración permite acercar esta herramienta a la toma de decisiones a escala regional, fundamentalmente para instituciones y or-ganizaciones locales, y colaborar con información en el diseño y desarrollo de políticas vinculadas al manejo ganadero adaptativo. Finalmente, discutimos los alcances de la herramienta y los desafíos futuros, asociados al desarrollo de sistemas de alerta temprana y mitigación de sequías en regiones áridas y semiáridas. ABSTRACT Environmental variability is a constant feature in arid and semiarid rangeland regions, being drought one of the main problems in extensive livestock production, with productive and economic impacts both at farm and regional scales. Regional monitoring of drought processes is a key and necessary tool, as a complement for active adaptive proposals and management, aimed at mitigation on production impacts. In this article, we propose a tool for drought monitoring in arid and semiarid areas, based on remote sensing data. The aim was to develop a monitoring system based on a spectral index, disaggregating regional biophysical heterogeneity into homogeneous units, by linking them to key decision moments associated with traditional livestock management in sheep farming systems from Northern Patagonia. Such integration allows bringing this tool closer to regional decision making, basically for local institutions and organizations, and give support with information for policy design and development related to adaptive livestock management. Finally, we discuss the scope of this tool and future challenges, regarding the development of early warning and drought mitigation systems in arid and semiarid regions.
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ABSTRACT This Proceedings documents the deliberations of the First UNCCD (United Nations Convention to Combat Desertification) Scientific Conference on ‘Understanding Desertification and Land Degradation Trends’, held in Buenos Aires,... more
ABSTRACT This Proceedings documents the deliberations of the First UNCCD (United Nations Convention to Combat Desertification) Scientific Conference on ‘Understanding Desertification and Land Degradation Trends’, held in Buenos Aires, Argentina, from 22 to 24 September 2009. It includes introductory and keynote presentations, summaries by Session Chairs, conference recommendations, and poster summaries. The Proceedings were edited by members of the Dryland Science for Development consortium, the body that organized the scientific format of the Conference.
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Morphological variation of the leaves of Aechmea distichantha Lem. plants from contrasting habitats of a Chaco forest: a trade-off between leaf area and mechanical support). Several authors have reported phenotypic plasticity for... more
Morphological variation of the leaves of Aechmea distichantha Lem. plants from contrasting habitats of a Chaco forest: a trade-off between leaf area and mechanical support). Several authors have reported phenotypic plasticity for bromeliad plants growing in contrasting habitats. Morphological and physiological differences of leaves seem to be an adaptation to water and light use, but there is also a compromise between carbon gain and the costs of sustaining static and dynamic loads. We hypothesized that plastic responses to habitat at the leaf level represent a trade-off between the photo- synthetic area for capturing light and mechanical support. In this study, we measured morphological and architectural vari- ables of central and basal leaves of Aechmea distichantha plants from the understory and forest edge, as well as anatomical variables of plants from each habitat. Understory plants had longer leaves, larger blade areas and greater length/width ratios than forest-edge plants. ...
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Abstract Increasing global aridity combined with changing environmental conditions might cause irreparable alterations in arid and semiarid ecosystems. Knowledge of within-species genetic diversity and adaptive responses, especially along... more
Abstract Increasing global aridity combined with changing environmental conditions might cause irreparable alterations in arid and semiarid ecosystems. Knowledge of within-species genetic diversity and adaptive responses, especially along climatic gradients, becomes critical to inform management, conservation and restoration efforts. We combine the analysis of neutral (microsatellites) and adaptive divergence (morphological traits in common garden experiments) between populations along a sharp precipitation gradient in the native Patagonian grass Festuca pallescens, to disentangle patterns of local adaptation and genetic diversity. The identification of genetically based traits under divergent selection denoted the existence of local adaptation in spite of extensive gene flow. Two plant growth patterns were detected associated with two ecological regions. In arid environments, a trade-off between not resigning foliage production, and reducing the exposure to drying agents resulted in a compacted plant architecture; while in dry-sub humid environments, populations exhibited a wide architecture to cope with rainfall and radiation interception. Increasing aridity and grazing might favor a compact plant architecture, and fragmentation might reduce genetic diversity across these environments. Being a widely distributed species, F. pallescens is an excellent model species to study adaptive responses across environmental gradients facing climate change predictions, especially in dryland rangelands that maintain multiple ecosystem functions.
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Abstract Seed germination is one of the earliest phenotypes expressed by plants, and the accuracy to germinate in the correct time and place is essential for plant population fitness. Cues that regulate germination have been exhaustively... more
Abstract Seed germination is one of the earliest phenotypes expressed by plants, and the accuracy to germinate in the correct time and place is essential for plant population fitness. Cues that regulate germination have been exhaustively characterized in laboratory experiments. However, the way in which seed populations respond to these cues and the ecological meanings of this phenomenon are scarcely known. To help filling this gap, we studied the thermic regulation of seed germination and its link with local climatic characteristics in Festuca pallescens populations, an iconic perennial grass species of Patagonia. By coupling thermal time models with field and environmental data, we evaluated seed responsiveness to temperature during germination of nine Festuca pallescens populations distributed across their complete longitudinal range in North Patagonia. The idea behind this experimental design was to search for inter-population differences in early life traits relevant for recruitment of the species, and associate seed traits with local environmental characteristics. F. pallescens populations showed strong differences in seed sensitivity to temperature for the thermal regulation of the germination rate, described by the population mean thermal time for germination (θ(50)) and its standard deviation (σθ). The greatest values of θ(50) and σθ corresponded to populations inhabiting harsh environments. Moreover, θ(50) of the different populations showed strong correlations with their local thermal environmental parameters, indicating a relation between seed physiological traits and climate across the longitudinal gradient. We did not observe inter-population differences in the minimum temperature that allows germination (Tb = -0.47 ± 0.19 °C). Higher θ(50) and σθ in populations from harsh climates may constitute a strategy of the species to increase fitness in hostile habitats, preventing anticipated germination and promoting a slower seed bank depletion in regions where establishment is highly limited.
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ABSTRACT The disruption of the natural post-disturbance recovery process, either by changes in disturbance regime or by another disturbance, can trigger transitions to alternative degraded states. In a scenario of high disturbance... more
ABSTRACT The disruption of the natural post-disturbance recovery process, either by changes in disturbance regime or by another disturbance, can trigger transitions to alternative degraded states. In a scenario of high disturbance pressure on ecological systems, it is essential to detect recovery indicators to define the period when the system needs more protection as well as the period when the system supports certain use pressure without affecting its resilience. Recovery indicators can be identified by non-linear changes in structural and functional variables. Fire largely modulates the dynamic and stability of plant communities worldwide, and is this the case in northwestern (NW) Patagonia. The ultimate goal of this study is to propose a structural–functional approach based on a reference system (i.e. chronosequence) as a tool to detect post-disturbance recovery indicators in forests from NW Patagonia. In NW Patagonia (40–42°S), we sampled 25 Austrocedrus chilensis and Nothofagus spp. communities differing in post-fire age (0.3–180 years). In each community we recorded structural (woody species cover and height, solar radiation, air temperature, relative humidity) and functional (annual recruitment of woody and tree species) attributes. We modeled these attributes in function of post-fire age and analized the relationship between a functional attribute and a Structural Recovery Index (SRI). Communities varying in time-since-last-fire were structurally and functionally different. Moreover, response variables showed non-linear changes along the chronosequence, allowing the selection of recovery indicators. We suggest to use vegetation variables instead of environmental variables as structural recovery indicators. Horizontal and Vertical Vegetation Heterogeneity indices provided the information necessary to describe vegetation spatial reorganization after fire. Tree species annual recruitment was a good indicator of the functional recovery of forest communities. The relationship between a functional attribute and SRI allowed us to detect phases with high- and low-risk of degradation during post-fire succession. High-risk phases (<36 years old) had the highest horizontal vegetation heterogeneity and scarce tree seedling density (<7000 seedlings ha−1 year−1). Whereas, low-risk phases (>36 years old) had the highest vertical vegetation heterogeneity and tree species seedling density (>10,000 seedlings ha−1 year−1). Due to the low structural–functional levels, communities at high-risk phases would be more vulnerable to antropic pressure (e.g. livestock raising, logging) than communities at low-risk phases. The proposed approach contributes to the sustainable management of forest communities because it allows to estimate the minimum structural–functional levels from which forest communities could be harvested.
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Abstract In arid ecosystems, recruitment dynamics are limited by harsh environmental conditions and greatly depend on the net outcome of the balance between facilitation and competition. This outcome can change as a consequence of... more
Abstract In arid ecosystems, recruitment dynamics are limited by harsh environmental conditions and greatly depend on the net outcome of the balance between facilitation and competition. This outcome can change as a consequence of degradation caused by livestock overgrazing. Also, distinct plant species may show a differential response to a common neighbour under the same environmental conditions. Therefore, ecosystem degradation could affect the net balance of plant-plant interactions, which can also depend on the functional traits of potential nurse species. The aim of this study is to assess the influence of alternative degradation states on (i) the density of seedlings of perennial species emerging in four microsite types, and on (ii) the relative interaction intensity (RII) between seedlings and potential nurses belonging to three functional types (deep- and shallow-rooted shrubs, and tussock grasses). During three years, we recorded seedling density of perennial species in four alternative degradation states in grass-shrubby steppes from northwestern Patagonia. The density of emerged seedlings of perennial species decreased sharply as degradation increased, showing non-linear responses in most microsites. Seedling density underneath deep-rooted shrubs was higher than underneath shallow-rooted shrubs and tussock grasses. Also, deep-rooted shrubs were the only functional type that recorded seedling emergence in highly degraded states. Deep-rooted shrubs had facilitative effects on the seedlings emerging and surviving underneath them, independently of ecosystem degradation. In contrast, RII between shallow-rooted shrubs and recently emerged seedlings, switched from positive effects in the less degraded states, to negative effects in the most degraded state. Tussock grasses recorded the weakest intensity of facilitative interactions with recently emerged seedlings, switching to competitive interactions as degradation increased. Our results suggest that species with key functional traits should be considered in management and restoration plans for rangelands with different degradation levels, since they have a strong influence in the net outcome of plant-plant interactions and in the recruitment dynamics of arid ecosystems.
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Dealing with complex challenges worldwide regarding sustainable development and environmental management requires applied frameworks to understand and manage change in complex social-ecological systems. In this regard, frameworks that... more
Dealing with complex challenges worldwide regarding sustainable development and environmental management requires applied frameworks to understand and manage change in complex social-ecological systems. In this regard, frameworks that have originated from different research arenas such as the State-and-Transition Model and the sustainable livelihoods approach provide a conceptual basis for theory and operative integration. The aim of this paper was to provide a conceptual model for social-ecological research and sustainable management in semi-arid pastoral systems. We suggest integrating the state-and-transition model by including structural and functional features of social-ecological systems into the sustainable livelihoods approach. Both attributes are analysed at a household level in five types of capital that typically comprise social-ecological systems: natural, human, manufactured, social and financial. We propose to perform the structural-functional analysis for each capital...
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ABSTRACT In Patagonia, arid and semiarid lands are being affected both by inappropriate management practices, which are leading to degradation, and by volcanic activity, whose effects are still unclear. This study aimed to test whether... more
ABSTRACT In Patagonia, arid and semiarid lands are being affected both by inappropriate management practices, which are leading to degradation, and by volcanic activity, whose effects are still unclear. This study aimed to test whether superficial deposition of volcanic tephra could benefit two of the most prominent Patagonian forage grass species (Poa ligularis and Pappostipa speciosa var. speciosa). Pots with P. ligularis and P. speciosa were kept under wet (W) and dry (D) conditions in the presence (T+) or absence (T−) of tephra for 105 days, and then were all well-watered. We determined the effects of tephra on soil water retention and conservation, soil moisture content (% v/v), plant growth, stomatal conductance (gs), and gs recovery capacity. The water regime significantly affected both species performance and gs. The presence of tephra increased soil water conservation, soil moisture content in wet conditions, and P. ligularis gs in wet conditions, and decreased senescence in dry conditions (9% in P. ligularis and 16% in P. speciosa). The presence of tephra allowed roots to grow in 8/10 and 2/10 pots in W conditions for P. ligularis and P. speciosa, respectively, and in only 1/10 pots in D conditions, only for P. ligularis. Tephra was also associated with gs recovery after dry conditions. Poa ligularis was more positively affected by tephra than P. speciosa, probably because P. ligularis has higher phenotypic plasticity. The positive effects of tephra may increase the resilience and resistance of P. speciosa and P. ligularis to periods of water shortage.
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SIDALC - Servicio de Informacion y Documentacion Agropecuaria de las Americas.
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Ecosystemic structural–functional approach of the state and transition model
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Silvopastoral systems (SPS) provide a wide range of non-provisioning ecosystem services including carbon (C) sequestration. Well-managed SPS outperform both grasslands/pastures and forests in terms of C by increasing soil and biomass C... more
Silvopastoral systems (SPS) provide a wide range of non-provisioning ecosystem services including carbon (C) sequestration. Well-managed SPS outperform both grasslands/pastures and forests in terms of C by increasing soil and biomass C storage. In this Chapter, C sequestration information from native forests and tree plantations under silvopastoral management in Argentina is provided. C sequestration at the stand level (including importance of soil, stand age, site quality and crown classes on the magnitude of C pools in above- and below-ground biomass and forest floor pools) and landscape level also are provided. Results highlight the importance of SPS as efficient carbon sink ecosystems. In the Chaco region, a mature forest of Aspidosperma quebracho blanco stored 67.6 Mg C ha−1 and this value decreased 17% when managed under the new guidelines of Forest Management Incorporating Livestock due to the reductions in tree density and shrub cover. In the same region, the soil organic C (100 cm depth) stored in a silvopastoral system ( Prosopis alba trees with Chloris gayana pasture) was higher than in an adjacent grazing beef cattle pasture (84.7 vs. 64.6 Mg C ha−1). The magnitude of the impact of implementing SPS on carbon stocks at the regional level across the Dry Chaco depended largely on the landowner’s decisions and on the initial natural vegetation condition. In the Mesopotamia region, SPS became a promising alternative for soil organic carbon storage and wood production simultaneously. In Patagonia, the total C stored in the SPS showed an intermediate value of 148.4 Mg C ha−1 compared with primary forest and adjacent open grasslands. Ponderosa pine plantation added carbon (65–210 Mg C ha−1) to the Festuca pallescens grasslands ecosystem (2.6 Mg C ha−1) which represents the baseline system under study. C storage in SPS is an important mitigation strategy in the context of rapidly increasing level of CO2 in the atmosphere and its potential effect on global climate change.
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Las ciencias agropecuarias constituyen un vínculo académico entre sociología y ecología. Actualmente, existe la predominancia de una perspectiva tecnocrática orientada a aumentar la productividad y la eficiencia, con una impronta muy... more
Las ciencias agropecuarias constituyen un vínculo académico entre sociología y ecología. Actualmente, existe la predominancia de una perspectiva tecnocrática orientada a aumentar la productividad y la eficiencia, con una impronta muy operativa e instrumental en el abordaje de muchos problemas complejos, relegando a segundo plano muchos otros aspectos que debieran abordarse en relación con la sustentabilidad y el desarrollo rural. El objetivo de este artículo es discutir el papel de las ciencias agropecuarias como nexo académico para abordar problemáticas socioambientales y la tensión que enfrenta la conservación de los ecosistemas rurales y el desarrollo territorial.
RESUMEN. Desarrollamos un modelo de estados y transiciones (MEyT) para el bosque de ñire (Nothofagus antarctica) en el norte de la Patagonia, con el fin de sintetizar el conocimiento disperso sobre las repuestas de este sistema al manejo... more
RESUMEN. Desarrollamos un modelo de estados y transiciones (MEyT) para el bosque de ñire (Nothofagus antarctica) en el norte de la Patagonia, con el fin de sintetizar el conocimiento disperso sobre las repuestas de este sistema al manejo silvopastoril. En base a una recopilación bibliográfica, a un taller de expertos seguido por sesiones de consulta y a relevamientos de campo propusimos los estados alternativos e identificamos los disturbios naturales y las prácticas de manejo más comunes que disparan cambios entre estados. Definimos siete estados, 13 transiciones de degradación y cuatro de restauración. Los bosques más íntegros están dominados por ñire y caña (Chusquea culeou) y el estado más degradado lo componen estepas sub-arbustivas de cadillo (Acaena splendens). Los estados intermedios serían los más aptos para el uso silvopastoril (bosque abierto de ñire con caña y pastizal, y bosque de ñire con pastizal), pero tienen una alta inestabilidad con las prácticas de manejo actuales, ya que, a causa de dicho manejo, con el paso del tiempo perderían el componente arbóreo y la cobertura de caña. El pastoreo, la extracción forestal, los incendios y las especies invasoras son los principales factores que disparan las transiciones de degradación. Estos efectos están agravados por la competencia del componente herbáceo con la vegetación arbórea, la mortandad de árboles y de caña, y por la erosión del suelo. La reversión de las transiciones de degradación no se produce de forma natural en el horizonte productivo del predio (~40 años) y requiere del uso de tecnologías como plantación, protección de los plantines de árboles y desarbustado. La identificación de las fases de riesgo en cada estado permite contar con alertas tempranas de deterioro, visualizar los efectos del manejo y orientar las prácticas para mantener la composición y estructura del bosque dentro de los límites que contemplan los aspectos productivo y ambiental. ABSTRACT. State-and-transition model of ñire forest in NW Patagonia as a tool for sustainable silvopastoral management. We built a state-and-transition model (S&TM) for the ñire forest system under silvopastoral use in northwestern Patagonia, with the aim to identify management effects on the vegetation. The model can help design practices that maintain the system within 'desired' conditions in the long term. Based on a review of published and unpublished literature, an expert workshop and consultation, and field surveys we proposed alternative states and their response to natural disturbances and current management practices. We defined seven states, 13 degradation and four restoration transitions, and the factors and levels that trigger the transitions (i.e., grazing, firewood extraction, fire and/or dispersal of invasive plants). The best-conserved forest is dominated by ñire (Nothofagus antarctica) and cane (Chusquea couleou), while the most degraded state corresponds to sub-shrubby steppes dominated by Acaena splendens (cadillo). The intermediate states are likely to be the most suitable for silvopastoral use (open ñire and cane forest, and ñire forest with grassland) but are highly unstable. Therefore, with the common current practices, the tree component and cane cover are lost with time. Invasion of exotic species, competition with the herbaceous vegetation, mortality of trees and cane, and soil erosion are the processes that trigger transitions. Most degradation transitions are difficult to revert because they require high-cost practices and/or have a long recovery time. Building the S&TM brought together scattered information about long-term changes in the vegetation. The identification of risk phases enables early warning of degradation.
Martínez Pastur (2017) State and transition model approach in native forests of Southern Patagonia (Argentina): linking ecosystem services, thresholds and resilience,
RESUMEN La variabilidad ambiental es una característica de regiones pastoriles áridas y semiáridas, siendo la sequía uno de los principales problemas en sistemas ganaderos extensivos, con implicancias productivas y económi-cas tanto a... more
RESUMEN La variabilidad ambiental es una característica de regiones pastoriles áridas y semiáridas, siendo la sequía uno de los principales problemas en sistemas ganaderos extensivos, con implicancias productivas y económi-cas tanto a escala predial como regional. El monitoreo regional de los procesos de sequía es una herramienta fundamental y necesaria, como complemento de propuestas y manejos adaptativos activos que busquen miti-gar los impactos sobre la producción. En el presente artículo proponemos una herramienta para el monitoreo de sequías en zonas áridas y semiáridas, basada en datos provistos por sensores remotos. El objetivo fue desarrollar un sistema de monitoreo basado en un índice espectral, desagregando la heterogeneidad biofísi-ca regional en unidades homogéneas, y relacionándola con los momentos clave de decisiones asociadas al manejo ganadero tradicional, en sistemas de producción ovina de Patagonia Norte. Esta integración permite acercar esta herramienta a la toma de decisiones a escala regional, fundamentalmente para instituciones y or-ganizaciones locales, y colaborar con información en el diseño y desarrollo de políticas vinculadas al manejo ganadero adaptativo. Finalmente, discutimos los alcances de la herramienta y los desafíos futuros, asociados al desarrollo de sistemas de alerta temprana y mitigación de sequías en regiones áridas y semiáridas. ABSTRACT Environmental variability is a constant feature in arid and semiarid rangeland regions, being drought one of the main problems in extensive livestock production, with productive and economic impacts both at farm and regional scales. Regional monitoring of drought processes is a key and necessary tool, as a complement for active adaptive proposals and management, aimed at mitigation on production impacts. In this article, we propose a tool for drought monitoring in arid and semiarid areas, based on remote sensing data. The aim was to develop a monitoring system based on a spectral index, disaggregating regional biophysical heterogeneity into homogeneous units, by linking them to key decision moments associated with traditional livestock management in sheep farming systems from Northern Patagonia. Such integration allows bringing this tool closer to regional decision making, basically for local institutions and organizations, and give support with information for policy design and development related to adaptive livestock management. Finally, we discuss the scope of this tool and future challenges, regarding the development of early warning and drought mitigation systems in arid and semiarid regions.