Rosina Soler

Determining Abiotic and Biotic Factors that Limit Transplanted Nothofagus pumilio Seedling Success in Abandoned Beaver Meadows in Tierra del Fuego

As ecosystem engineers, North American beavers (Castor canadensis) change many environmental conditions in water-sheds, felling trees, damming streams, and flooding riparian zones. In Tierra del Fuego, where beavers were introduced in 1946, these alterations have produced meadows that appear to be long-term alternate stable states, lacking signs of resilience and natural forest regeneration. The aim of this work was to determine the abiotic and biotic factors that affect native tree seedling success in abandoned beaver meadows in Nothofagus pumilio forests. Environmental conditions including light, soil moisture, herbaceous plant community composition, and reinvasion potential were measured in areas impacted by beavers and in unimpacted old-growth forests. Additionally, we monitored the survival and success of N. pumilio seedlings transplanted in plots where meadow vegetation was cleared. Tree seedlings showed little growth, and survival varied by type of beaver impact. While survival was high and similar to unimpacted sites in zones cut but not flooded by beavers, it was significantly lower in meadow zones that were previously flooded and cut, compared to old-growth forests. We found that the reinvasion of herbaceous plants into transplantation study plots was negatively related to tree seedling survival, and herbaceous (monocot) plant cover itself was related to beaver-created gradients in soil moisture and light availability. Overall, these abiotic changes modified the meadow’s plant community and enhanced herbaceous vegetation cover, particularly monocots and exotics, thus hindering transplanted seedling survival.

Are silvopastoral systems compatible with forest regeneration? An integrative approach in southern Patagonia

We used an integrated approach to analyze the influence of silvopastoral management on the biotic and abiotic factors influencing on the natural recruitment of native forests in Tierra del Fuego (Argentina). The probabilities of transition from flowers to seeds to seedlings were estimated in forests with silvopastoral management (i.e., stands that had been both grazed and thinned), secondary growth stands, and unmanaged old-growth areas. Pre-dispersal losses were caused by microclimate and insect predation acting on flowers and immature fruits. Post-dispersal losses resulted from the impact of reduced litterfall and microclimate. But the most critical stage of the overall cycle was seedling establishment. Silvopastoral practices and stand age modified the main drivers of regeneration. While flowering was unaffected by management, fruiting and seed production were more successful in unmanaged forests. Seedling establishment and survival were favored by canopy cover reduction in silvopastoral stands. The increase of solar radiation and soil moisture in managed forests positively influenced the seedling establishment and survival, while in second-growth forests it was limited by suitable micro-site availability. Thinning practices aimed at increasing the understory heterogeneity in mature forests and restoring canopy complexity of second-growth stands could be suitable for sustainable management of these temperate forests.

Seasonal diet of Lama guanicoe (Camelidae: Artiodactyla) in a heterogeneous landscape of South Patagonia>

La heterogeneidad de habitat, distintos ensambles de especies vegetales y las actividades productivas en bosques del genero Nothofagus condicionan la disponibilidad de alimento para los herbivoros nativos. Este trabajo evalua la dieta estacional de Lama guanicoe vinculada a la vegetacion, los tipos de habitat y el manejo forestal en Tierra del Fuego. Se realizaron censos de vegetacion (n = 206) y se estudio la dieta de L. guanicoe mediante recoleccion de heces y analisis micro-histologico (n = 4 en cuatro areas, durante las cuatro estaciones). Las areas abiertas tuvieron la mayor riqueza especifica, mientras que los valores mas bajos correspondieron a bosques primarios de Nothofagus pumilio. La dieta de L. guanicoe incluyo 25 especies y 13 generos de plantas y un musgo (Sphagnum spp.). Nothofagus pumilio (21,6 %), Carex spp. (17,2 %), Misodendrum spp. (10,6 %) y Deschampsia spp. (8,6 %) fueron los items mas frecuentes en la dieta. Se registraron diferencias estacionales tanto en la composicion como en la amplitud del nicho trofico: el consumo de pastos fue continuo durante todo el ano, el ramoneo de arboles disminuyo en invierno y aumento el consumo de arbustos perennes. Este estudio confirma que el guanaco utiliza una amplia variedad de ambientes, incluyendo bosques cosechados. En verano y primavera los bosques de Nothofagus spp. fueron los principales sitios de alimentacion para los guanacos, dependiendo mas del alimento en areas abiertas durante el invierno. El conocimiento de las interacciones planta-herbivoros nativos en paisajes con manejo agro-forestal podria mejorar los planes de manejo hacia un uso ecologicamente sustentable

Retention Forestry in Southern Patagonia: Multiple Environmental Impacts and Their Temporal Trends

SUMMARY Harvesting with variable retention (VR) applied in Nothofagus forests combines two types of retention: patches of original forest (aggregates) and single isolated homogeneously distributed trees (dispersed). This study assesses the assumption that VR maintains mature forests conditions after harvesting by synthesizing 605 individual results from long-term studies in two regions of Tierra del Fuego (Argentina) with permanent monitoring. VR effects on (i) forest structure, (ii) microenvironment, (iii) biodiversity, and (iv) forest reproduction, were investigated. Aggregated retention had no effect on forest structure and microenvironmental variables, but increased biodiversity variables and forest reproduction compared to unmanaged primary forest (control). Dispersed retention negatively affected the forest structure, increased biodiversity, but did not affect microclimate and forest reproduction when compared to primary forest. Thus, the ecological conditions of N. pumilio forests are influenced by variable retention harvesting, but direction and magnitude of the effect depend on the treatment and differ among groups of variable. Inside aggregates several primary forest components and conditions were maintained.

Linking potential biodiversity and three ecosystem services in silvopastoral managed forest landscapes of Tierra del Fuego, Argentina

ABSTRACT Several studies confirm that biodiversity loss endangers ecosystem services (ES) supply and human well-being. A better understanding of biodiversity–ES relationships and effects of biodiversity loss on ES supply is needed. The objective was to determine relationships between potential biodiversity and three ES in Patagonia where cattle ranching under silvopastoral use occurs. We used grids of potential biodiversity (plant species richness) and three ES, provisioning (cattle stocking rate), regulating (CO2 sequestration) and cultural (geo-tagged digital-images). Potential biodiversity was negatively related to provisioning, but no significant relations were detected with regulating and cultural. These relations showed regional differences related to forest landscape distribution. High values of regulating were found in southern areas being coincident with high potential biodiversity. Opposite trends (negative relationship with biodiversity) was observed for provisioning in eastern and western regions where provisioning decrease from N-S. Results suggest that provisioning do not overlap spatially with the higher values of potential biodiversity maps, which is an advantage for land use planning when conservation and management requirements must be combined. Our results are the first contribution for Patagonia to underpin scientific and institutional efforts to connect biodiversity conservation with ES maintenance. However, further studies must be addressed including more ES and regions. EDITED BY Sandra Luque

Biodiversity potential of Nothofagus forests in Tierra del Fuego (Argentina): tool proposal for regional conservation planning

It is difficult to map and quantify biodiversity at landscape level in areas with low data availability, despite demand from decision-makers. We propose a methodology to determine potential biodiversity pattern using habitat suitability maps of the understory plant species with highest cover and occurrence frequency in the three different forests types of Tierra del Fuego (Argentina). We used a database of vascular plants from 535 surveys from which we identified 35 indicative species. We explored more than 50 potential explanatory variables to develop habitat suitability maps of the indicative species, which were combined to develop a map of the potential biodiversity. Correlation among environmental, topographic and forest landscape variables were discussed, as well as the marginality and the specialization of the indicative species. We detected differences in the niches of the species prevailing in the three forest types. The developed map of potential biodiversity uncovered hotspots of biodiversity in the ecotone of Nothofagus pumilio and N. antarctica as well as in the wettest part of the mixed N. pumilio–N. betuloides forests. It allowed thus to identify forest areas with different conservation potential and can be readily used as a decision support system for conservation and management strategies at different scales including the identification of land-use conflicts (e.g. of biodiversity with timber production and livestock) and the development of a network of protected areas, which currently does not cover the forests of highest conservation value.

Neochelanops michaelseni (Pseudoscorpiones: Chernetidae) as a potential bioindicator in managed and unmanaged Nothofagus forests of Tierra del Fuego

Abstract Bioindicators could act as early warning indicators of environmental changes, ecosystem stress or taxonomic diversity. Pseudoscorpions have rarely been used as bioindicators, due to lack of information about their ecology, habitat selection, niche preferences and requirements, especially in southern Nothofagus forests. We studied the distribution and abundance of a pseudoscorpion species, Neochelanops michaelseni (Simon 1902), in different vegetation types (Nothofagus antarctica and N. pumilio forests, grasslands and peatlands) and examined how this species responded to different forest uses (harvesting and silvopastoral management), to explore its utility as a bioindicator. The study was conducted on long-term plots located at two ranches in Tierra del Fuego, using pit-fall traps during one summer. Neochelanops michaelseni abundance was higher in Nothofagus forests than in open ecosystems, which could be attributed to their affinity for litter and coarse woody debris. In N. pumilio forests, the pseudoscorpions were sensitive to harvesting, with similar abundances in harvested forests (aggregated and dispersed retentions) and grasslands. In N. antarctica forests, differences were not detected among unmanaged and silvopastoral managed forests, probably due to higher understory plant growth, and lesser diminishing of litter and debris by thinning than by harvesting. We conclude that the pseudoscorpion, N. michaelseni, can be a good bioindicator for ecosystem conservation and for evaluating recovery rate in the ecological conditions of impacted Nothofagus forests, and that management practice intensities should be regulated to create more suitable habitats for pseudoscorpion diversity conservation.

Variable retention management influences biomass of Misodendrum and Usnea in Nothofagus pumilio southern Patagonian forests

Variable retention systems (retention of some existing trees in different densities along with significant elements of the original forest after logging) aim to mitigate the impact of harvesting in native temperate forests, improving biodiversity conservation in managed stands. This study evaluates the effect of variable retention harvesting on epiphytic lichens (Usnea barbata) and mistletoes (Misodendrum punctulatum) in Nothofagus pumilio forests. The abundance of these canopy-dwelling species can be estimated by measuring their litter fall. We quantified mistletoe, lichen and tree litter fall monthly for 3 years. Tree and lichen biomasses were influenced by canopy cover, being higher in primary forests than in harvested stands. However, aggregated retention showed the highest mistletoe biomass production. Furthermore, mistletoe biomass increased while lichen biomass decreased over the years after harvesting. Variable retention was useful in maintaining both lichen and mistletoe biomass after harvest, but aggregates were not enough to maintain the original level of lichen populations. Forest harvesting with variable retention generates positive (litter input) and negative (decline of host growth) effects of mistletoes and epiphytic lichens at community level, which should be evaluated during conservation and management planning.

Silvopastoral Systems Under Native Forest in Patagonia Argentina

In Patagonia, silvopastoral systems in Nothofagus antarctica (nire) forest has become an economically, ecologically and socially productive land-use system. Patagonian experience with silvopastoral systems in the past 15 years is reviewed in this chapter. The productivity and nutritive value (crude protein content and dry matter, DM, digestibility) of understorey grassland were dependent on the interaction of environmental (mainly soil water availability and light intensity) and system level management factors. Planned thinning in secondary forest stands provide wood production and also improve the undestorey DM production by increasing incoming radiation. Within a Management Plan, two thinning intensities, depending on stand water stress conditions, are proposed. In addition, the use of Reineke’s Stand Density Index (SDI) is recommended to be used when deciding thinning intensities for different canopy covers. Livestock production is the main source of annual income from silvopastoral systems in N. antarctica forest where cattle and mixed livestock production (cattle + sheep) is the main activity. Animal performance at the whole-farm scale is described by comparing a traditional extensive grazing management with an adaptive silvopastoral management. The management factors that favor adoption of silvopastoral system are strategic separation of homogenous areas (grass steppe, forest and riparian meadows), stocking rate adjustments based on grassland net primary productivity and the protection of regeneration from herbivores browsing by using individual tree guard. Also, data from litter decomposition, nutrients dynamic and carbon storage are informed. Finally, aspects related to criteria and indicator (C&I) to assess nire forest’s sustainability under silvopastoral use and biodiversity conservation issues are also presented.

Assessing Knowledge Production for Agrosilvopastoral Systems in South America

ABSTRACT In recent decades agroforestry has undergone significant development in Latin America. South America generates the most scientific research on the topic in the region. We conducted a comprehensive review and analysis of knowledge production for South American agroforestry that includes livestock grazing, known as agrosilvopastoralism (AS), examining how different sociopolitical factors such as sources of funding, institutional priorities, and international cooperation can bias the direction and objectives of scientific research. We assessed the major attributes of scientific publications on the topic (25 articles per country; overall n = 210) and the potential factors underlying the processes of research and development in the region. The tree component was the most studied,while the livestock component received less attention. Studieswere mainly focused on the production of goods and services (monetary or nonmonetary approaches), except in Brazil,where conservationwas the major study objective. Stakeholders were involved in more than half of the studies (60%), and they were mostly ranchers and local producers. More than half (70%) of the studies offered recommendations based on their results, and such recommendations were mostly concerned with the management of agrosilvopastoral system components. In general, studies were led just as often by local as foreign first authors and coauthored by more than three people as part of interinstitutional working groups. Brazil, Argentina, Colombia, and Chile had more frequent cooperation among institutions and countries but mainly used their own funding. In contrast, Bolivia, Ecuador, and Peru had almost 100% of their studies supported by foreign countries (North America and Europe). Countries with greater internal funding of research generated more long-term studies. Besides this, two clear trends were detected: 1) conservation and social aspects were mainly supported by sources from external countries led by foreign principal investigators, and 2) production issues were supported from sources within countries and supported high levels of cooperation among institutions.