Alicia Moretto

How to know the fungi: combining field inventories and DNA‐barcoding to document fungal diversity

The fungi kingdom is among the most diverse eukaryotic lineages on Earth with estimates of several million extant species (O’Brien et al., 2005; Blackwell, 2011; Taylor et al., 2014). Fungi play critical roles in carbon andnutrient cycling of terrestrial and aquatic ecosystems, and they are important pathogens and mutualists (Read & Perez-Moreno, 2003; Taylor et al., 2012; Grossart et al., 2016). More than 80% of plant species form symbioses with fungi and these symbioses have been crucial to the colonization of terrestrial ecosystems (Field et al., 2015a; Selosse et al., 2015). Despite their impacts on primary ecosystem functions, assessments of fungal biodiversity estimate that only c. 10% of fungal species have been described (Bass & Richards, 2011; Hibbett et al., 2011). Traditionally, specimen-based taxonomic studies have been the only way to discover new species. Because most fungi have microscopic life-stages and convergent morphological features (Rivas-Plata & Lumbsch, 2011; Wynns, 2015), many fungal groups remain severely undersampled. DNA-barcoding and highthroughput sequencing methods have provided a new framework for studying fungal biodiversity (Fierer et al., 2012; Schoch et al., 2012; Myrold et al., 2014), and diversity estimates based on environmental sequences have increased exponentially. Although these ‘sequence-based classification and identification’ methods are a powerful means to rapidly detect hidden diversity, careful interpretation of these data is needed to make accurate inferences (K~oljalg et al., 2013; Lindahl et al., 2013; Nguyen et al., 2015; Hibbett et al., 2016). In particular, many environmental sequences cannot be associated with a known fungal species or lineage. This remains a major challenge to decipher fungal community composition and understand ecological roles of fungi in leaf litter, soil, or inside plants (Yahr et al., 2016). In some cases, these fungi are truly undescribed and their ecological roles are unknown but in other cases they represent described taxa for which no sequence is available (Nagy et al., 2011; Nilsson et al., 2016). DNA barcoding of herbarium specimens and culture collections is extremely valuable to link unidentified sequences to known taxa (e.g. Brock et al., 2009; Nagy et al., 2011; Osmundson et al., 2013; Garnica et al., 2016).DNA sequences have been generated from fungal type specimens > 200 years old (Larsson & Jacobsson, 2004), but in many cases obtaining sequences from historical material is challenging (Dentinger et al., 2010). Today’s threats to biodiversity from habitat loss and climate change are occurring at an unprecedented scale, and it is possible that many species may become extinct before they have been discovered (Costello et al., 2013; Monastersky, 2014). In the need to describe and protect as many species as possible we addressed the following questions: what are the best methods to rapidly document fungal biodiversity? Are traditional, specimen-based approaches still useful?

Long-term forest management research in South Patagonia - Argentina: lessons from the past, challenges from the present.

Argentina ha basado su economia en la agricultura y el ganado, donde el bosque ha sido visto como un obstaculo para el desarrollo. La cosecha forestal en Patagonia Sur ha sido una actividad basada en la colonizacion y explotacion de nuevas areas. Esta se realiza principalmente en bosques primarios sin ningun manejo silvicola posterior. A pesar de que el manejo actual no es sustentable, la investigacion cientifica ha definido las bases para conservar, proteger y mejorar las propuestas de manejo forestal para los bosques nativos de Patagonia Sur. Las primeras parcelas de estudio a largo plazo (1965-1966) basaron su monitoreo en parametros economicos y estructura forestal, estableciendose cerca de veinte parcelas en bosques fiscales de Tierra del Fuego. La mayoria fueron destruidas o discontinuadas debido a la falta de planificacion del uso de la tierra, escaso interes social en la investigacion, falta de compromiso de instituciones, y poca colaboracion con empresas forestales. Posteriormente, un segundo grupo de nueve parcelas se establecio en Patagonia Sur (1993-2004) basado en la colaboracion entre empresas privadas e instituciones nacionales. Los objetivos incluyeron parametros economicos y ecologicos. Las parcelas se establecieron en tierras privadas conjuntamente con empresas privadas y estancieros, mediante la firma de acuerdos y proyectos de investigacion. Los principales problemas encontrados fueron: falta de compromiso de las administraciones forestales, ausencia de proyectos financiados a largo plazo, y que la responsabilidad de las parcelas continua bajo la iniciativa personal de los investigadores participantes. El estudio de las parcelas permitio: (i) proponer nuevos sistemas de regeneracion basados en la maximizacion del rendimiento y el mejoramiento del valor de conservacion de los bosques manejados (e.g., retencion variable y sistemas silvopastoriles), (ii) determinar la factibilidad economica de aplicacion de tratamientos intermedios, (iii) determinar lineas base y definir los impactos de distintos sistemas silvicolas, (iv) proponer metodologias de monitoreo de amplio espectro y establecer areas demostrativas de manejo, y (v) proveer areas y conocimientos para entrenar profesionales en practicas de manejo forestal y conservacion de la biodiversidad. Las parcelas permanentes ya establecidas en los bosques de Nothofagus de Patagonia Sur y las bases de datos obtenidas podrian servir como punto de partida para definir un nucleo regional que pueda participar en el International Long Term Ecological Research para asegurar el uso sustentable de los bosques nativos.

Producción diferencial de biomasa en plántulas de Nothofagus pumilio bajo gradientes de luz y humedad del suelo

Las propuestas silviculturales disminuyen la apertura del dosel, estimulando el crecimiento de las plantulas al modificar la disponibilidad de luz y humedad del suelo. La supervivencia dependera de su adaptacion a estas nuevas condiciones ambientales. El objetivo fue evaluar la produccion de biomasa de plantulas bajo gradientes de luz y humedad del suelo en condiciones controladas de luz, riego y temperatura. Se emplearon plantulas de 2-3 anos en macetas bajo invernaculo, estudiandose tres niveles de luz: 4%-26%-64% de luz natural incidente; y dos niveles de humedad del suelo: 40-60% y 80-100% de capacidad de campo. Mensualmente se evaluaron area foliar y biomasa, de hojas, tallos, raices gruesas y finas. La biomasa total y compartimentada, el area foliar y sus relaciones variaron entre meses y niveles, de humedad y de luz. Al finalizar la temporada de crecimiento, la biomasa fue mayor en alta luminosidad y menor humedad del suelo (1,58 g planta-1), respecto de alta humedad (0,49 g planta-1). La biomasa aerea fue mayor bajo luminosidad media (0,30 g planta-1 vs. 0,12-0,26 g planta-1), mientras que la subterranea aumento con la luz (0,20 g planta-1 vs. 0,07-0,16 g planta-1). Las plantulas modificaron su produccion de biomasa aerea y/o subterranea segun las condiciones hidrico/luminicas, generando menores relaciones de biomasa y area foliar bajo mayores niveles de luz. Los distintos sistemas silvicolas deben tener en cuenta los cambios que producen sobre ambos factores (luz y humedad del suelo) para maximizar el potencial de crecimiento aereo y/o subterraneo de la regeneracion natural

ABOVE- AND BELOW-GROUND NUTRIENT TISSUE CONCENTRATION AND LEAF PIGMENT CHANGES IN PATAGONIAN WOODY SEEDLINGS GROWN UNDER LIGHT AND SOIL MOISTURE GRADIENTS

To understand the ecophysiology of natural regeneration above- and below-ground nutrient tissue concentration and leaf pigment changes in Nothofagus pumilio (lenga) seedlings grown in three light intensities (4%, 26% and 64% of natural irradiance) and two soil moisture levels (40–60% and 80–100% soil capacity) under greenhouse controlled conditions were evaluated. Carbon (C), nitrogen (N), phosphorus (P), magnesium (Mg), potassium (K), calcium (Ca) and pigment (chlorophylls and carotenoids) were measured on seedlings. Carbon, N, Mg, K and Ca increased in low light intensity and soil moisture treatments, while P decreased. Nutrients were higher in above- than in below-ground biomass. Chlorophylls were lower in high light treatments, while carotenoids increased their content. All pigments were greater in low soil moisture treatments. These changes are closely related to their photosynthetic plasticity and biomass compartmentalization. Plants growing in high light were more efficient to produce the same amount of plant biomass.

Litter production in the Nothofagus forests of Tierra del Fuego, Argentina

Differences in the amount of litter-fall in arboreal species constitute an important factor to understand the nutrient cycle inside a managed forest. The objective was to determine the litter production in Nothofaguspumilio (lenga), N. antarctica (nire) and N. betuloides (guindo) forests in Tierra del Fuego. Litters was collected during the period of highest fall (February-May), sorting its components into leaves, branches, seeds and miscellaneous (flowers, valves, etc.). Leaves represented the most important component, being significantly higher in lenga (79%) than in guindo (65%) or nire (54%). Seeds also presented bigger differences, showing a behaviour inversely proportional to that of leaves: nire (8.7%), guindo (3.0%) and lenga (0.8%). No difference was detected in branches and miscellaneous. The studied forest types showed different strategies of energy distribution, for example, being deciduous or evergreen, or of mass seed production in exceptional years.