Thomas Kitzberger

National University of Comahue | UNCo · Centro Regional Universitario Bariloche

Background Understanding the drivers of fire is frequently challenging because some of them interact and influence each other. In particular, vegetation type is a strong control of fire activity, but at the same time it responds to physical and human factors that also affect fire, so their effects are often confounded. We developed a 30 m resolutio...

Plants inhabiting contrasting physical conditions might develop local adaptations overriding the homogenizing effects of gene flow. Hypotheses of local adaptation on phenotypic, genomic, and environmental variation under extreme precipitation regimes were tested in the Patagonian conifer Austrocedrus chilensis. Common garden experiments on progeny...

Background Fire regimes in many biomass-rich ecosystems worldwide are dominated by high-severity fires. Many of these systems lack fire-resistant traits or post-fire regeneration strategies. Understanding under which environmental and weather conditions they experience less severe fire is crucial for maintaining their persistence in the landscape....

The benefits of masting (volatile, quasi-synchronous seed production at lagged intervals) include satiation of seed predators, but these benefits come with a cost to mutualist pollen and seed dispersers. If the evolution of masting represents a balance between these benefits and costs, we expect mast avoidance in species that are heavily reliant on...

Muchos bosques del norte de la Patagonia andina argentina se han expandido en los últimos 100 años, avanzando sobre áreas incendiadas. En este artículo estimamos las respuestas de largo plazo de los principales tipos forestales de bosque alto, Nothofagus pumilio (lenga), Nothofagus dombeyi (coihue) y Austrocedrus chilensis (ciprés de la cordillera,...

Potencialidad de mapeo de la altura del dosel en el bosque andino patagónico a partir del sensor satelital LiDAR GEDI

Aim Our understanding of the mechanisms that maintain forest diversity under changing climate can benefit from knowledge about traits that are closely linked to fitness. We tested whether the link between traits and seed number and seed size is consistent with two hypotheses, termed the leaf economics spectrum and the plant size syndrome, or whethe...

This work evaluates the forest fire severity of the Steffen- Martin fire, which occurred in Nahuel Huapi National Park between December 2021 and April 2022. Fire severity is a descriptor of environmental fire impact and a determining factor to explain the response of the ecosystem to this dis- turbance. Satellite images (Sentinel 2) were used to es...

The relationships that control seed production in trees are fundamental to understanding the evolution of forest species and their capacity to recover from increasing losses to drought, fire, and harvest. A synthesis of fecundity data from 714 species worldwide allowed us to examine hypotheses that are central to quantifying reproduction, a foundat...

Warming trends are altering fire regimes globally, potentially impacting on the long-term persistence of some ecosystems. However, we still lack clear understanding of how climatic stressors will alter fire regimes along productivity gradients. We trained a Random Forests model of fire probabilities across a 5°lat × 2° long trans-Andean rainfall gr...

Lack of tree fecundity data across climatic gradients precludes the analysis of how seed supply contributes to global variation in forest regeneration and biotic interactions responsible for biodiversity. A global synthesis of raw seedproduction data shows a 250‐fold increase in seed abundance from cold‐dry to warm‐wet climates, driven primarily by...

Positive interactions between non-native species can accelerate their invasion rate and exacerbate their impacts. This has been shown for non-native mammals that disperse invasive ectomycorrhizal fungi (EMF), in turn facilitating the invasion of non-native tree species. Mammal-mediated dispersion is assumed to be the main mechanism of EMF long dist...

Sustainable management of native species is essential in regions where forest is continually decreasing, such as South America. A first step for sustainable management is to develop models of productivity and site quality, which are usually related to the height of dominant trees. The aim of this study was to model the height (h) of dominant trees...

Extreme events can have larger impacts on ecosystems than gradual changes of average conditions. This article identifies the different properties of drivers of extreme events, often related to extreme weather or climate events, which are becoming more frequent or more intense, and the derived ecological responses. Extreme ecological responses occur...

Climate forcings determine the episodic occurrence of local climate anomalies that trigger the occurrence of masting events (massive, synchronized and intermittent seed production by perennial plants). This suggests some kind of phase-locking of the reproductive cycles of individual plants to the climatological cycle, thus further reinforcing repro...

Large herbivores prefer to consume plants with high concentration of digestible carbohydrates and protein, whereas fire spread is favored by foliage characteristics that induce rapid ignition and high radiant energy. We tested in eight Patagonian woody plants whether foliar traits that determine dry matter and nitrogen digestibility to browsing her...

Maintenance of tree cavity supply is a global conservation priority for forest wildlife, which requires understanding the ecology and population dynamics of cavity-bearing trees. Explaining the occurrence of cavities in trees is particularly important in ecosystems where most secondary cavity-users (SCUs) are critically dependent on the slow format...

Canopy insects are the main consumers in forests, and understanding their ecological role includes considering their effects on litter decomposition and nutrient cycling. We experimentally evaluated how litter decomposition is shaped by the decomposition environment and by litter traits shaped by forest moisture origin and chronic insect activity....

Abstract: Several mid‐sized urban areas have established boundaries overlapping with the distribution of Austrocedrus chilensis (D.Don) Pic.Serm. & Bizzarri forests in Patagonia. These forests suffer a disease whose primary cause is the aggressive pathogen Phytophthora austrocedri. This study analyzes the factors related to Austrocedrus disease in...

Significance Forests are experiencing growing risks of drought-induced mortality in a warming world. Yet, ecosystem dynamics following drought mortality remain unknown, representing a major limitation to our understanding of the ecological consequences of climate change. We provide an emerging picture of postdrought ecological trajectories based on...

Questions Increased wildfire activity is resulting in plant community‐type conversions worldwide. In some regions, fire‐sensitive forests are being replaced by flammable fire‐resilient communities, increasing the likelihood of reburning due to positive fire feedbacks. Here we evaluated whether fire severity affects postfire plant community flammabi...

Severe droughts have the potential to reduce forest productivity and trigger tree mortality. Most trees face several drought events during their life and therefore resilience to dry conditions may be crucial to long-term survival. We assessed how growth resilience to severe droughts, including its components resistance and recovery, is related to t...

Sustainable forest management aims to both enhance biodiversity and tree productivity. However, trade-offs may exist between these objectives, e.g. arthropod diversity and associated arthropod herbivory can reduce tree growth and survival. Tree productivity and biodiversity may also show non-linear responses to management intensity, making applied...

Contagious processes such as fire and seed dispersal may affect landscape structure, composition and dynamics, and are in turn modulated by structural landscape attributes. Vegetation-fire self-reinforcing processes that lead to the dominance of either pyrophyllic or pyrophobic vegetation are well documented worldwide, but it remains unclear how th...

Tree mortality is a key driver of forest dynamics and its occurrence is projected to increase in the future due to climate change. Despite recent advances in our understanding of the physiological mechanisms leading to death, we still lack robust indicators of mortality risk that could be applied at the individual tree scale. Here, we build on a pr...

Understanding the relationship between flammability and time since fire (TSF) is crucial for predicting ecosystem responses to changes in fire regimes. Landscapes composed of alternative stable states displaying positive fire-vegetation feedbacks are especially sensitive to these changes. We derived TSF-flammability functions (Logistic, Olson, Mois...

Under changing climates, the persistence of montane subtropical taxa may be threatened as suitable habitats decrease with elevation. We developed future environmental niche models (ENNMs) for Podocarpus parlatorei, the only conifer from southern Yungas in South America, and projected it onto two greenhouse gas concentration scenarios based on 13 gl...

Increasing evidence indicates that forest disturbances are changing in response to global change, yet local variability in disturbance remains high. We quantified this considerable variability and analyzed whether recent disturbance episodes around the globe were consistently driven by climate, and if human influence modulates patterns of forest di...

This zip folder contains the full set of scripts to run the model used to simmulate the effects of fire and fragmentation on dichotomic landscapes composed by a pyrophitic and a pyrophobic plant community. The imput landscapes are included in the Input folder The results of the model, run with the initial landscapes are included in the Results fold...

The persistence of non-serotinous pines in Mediterranean forests can be threatened by climate-mediated changes in fire regimes that may favor the dominance of resprouters or other fire-adapted species. Recovery of non-serotinous pines after large wildfires is often determined by their ability to grow under the canopy of promptly established resprou...

This presentation, prepared for a forum of economists t the University of Río Negro working on urban resilience highlights the changes in our relation to fire, from a mutualistic one enabling us to climb the ecological pyramid to a antagonism between humans living in forest landscapes such as Bariloche, a city highly dependent on tourism. We exami...

Presentamos los resultados mas recientes sobre la dinámica del fuego en sistemas forestales de Patagonia Andina. La charla se centra en los principales condicionantes para el manejo del fuego en la región, en el contexto de la ley de presupuestos mínimos para el manejo del fuego.

Disturbances produced by volcanic eruptions are part of natural ecosystem dynamics. Soil formation and nutrient cycling depend on the decomposition both of organic matter buried under the ashes and on the litter produced after the disturbance. Here we evaluated leaf litter decomposition in Nothofagus dombeyi (coihue) forests affected by massive ash...

Los disturbios generados por erupciones volcánicas son parte de la dinámica natural de los ecosistemas. La formación de suelo y el reciclado de nutrientes dependen de la descomposición tanto de la materia orgánica enterrada bajo las cenizas, como de la broza vegetal aportada luego del disturbio. Este trabajo examinó la descomposición de hojarasca e...

Abstract 1. In the context of ongoing climatic warming, forest landscapes face increasing risk of conversion to non-forest vegetation through alteration of their fire regimes and their post-fire recovery dynamics. However, this pressure could be amplified or dampened, depending on how fire-driven changes to vegetation feed back to alter the extent...

Planted and invading non-native plant species can alter fire regimes through changes in fuel loads and in the structure and continuity of fuels, potentially modifying the flammability of native plant communities. Such changes are not easily predicted and deserve system-specific studies. In several regions of the southern hemisphere, exotic pines ha...

Vulnerability to climate change, and particularly to climate extreme events, is expected to vary across species ranges. Thus, we need tools to standardize the variability of regional climatic legacy and extreme climate across populations and species. Extreme climate events (e.g. droughts) can erode populations close to the limits of species’ climat...

Los disturbios generados por erupciones volcánicas son parte de la dinámica natural de los ecosistemas. La formación de suelo y el reciclado de nutrientes dependen de la descomposición tanto de la materia orgánica enterrada bajo las cenizas, como de la broza vegetal aportada luego del disturbio. Este trabajo examinó la descomposición de hojarasca e...

Este proyecto investigó algunos de los impactos asociados con la presencia histórica de ganado bovino en bosques nativos de coihue (Nothofagus dombeyi) del norte de la Patagonia Andina. Para ello se compararon sitios apareados que fueron ocupados por ganado o permanecieron libres de ganado por más de 50 años, a lo largo de un gradiente regional de...

The present study assessed the impacts generated by the long-term presence of domestic cattle in native evergreen forests (Nothofagus dombeyi) of the northern Patagonian Andes, Argentina. We compared paired sites that were historically used by or remained free of livestock for more than 50 years along a regional moisture gradient. Understory plant...

Predicting wildfire under future conditions is complicated by complex interrelated drivers operating across large spatial scales. Annual area burned (AAB) is a useful index of global wildfire activity. Current and antecedent seasonal climatic conditions, and the timing of snowpack melt, have been suggested as important drivers of AAB. As climate wa...

Temporal trends in instrumental seasonal precipitation (1972–2006). Left panels: trend magnitude based on Theil-Sen median slope estimator for JFM, AMJ, JAS respectively. Right panels: trend significance based on Mann-Kendall test. Cool colors indicate increasing precipitation; warm colors indicate decreasing precipitation. (TIF)

General Circulation Models and runs used for the A1B emission scenario ensemble. (DOCX)

Spatial correlation of PC5 (preceding year spring temperature, positive correlation with AAB, 11% variance in AAB explained) from PCA analysis of z coefficients of a complete multiple regression model in each grid cell. Red (blue) colors indicate increases (decreases) in log-transformed AAB. (TIF)

2017. Ecosystem dynamics and management after forest die-off: a global synthesis with conceptual state-and-transition models. Ecosphere 8(12): Abstract. Broad-scale forest die-off associated with drought and heat has now been reported from every forested continent, posing a global-scale challenge to forest management. Climate-driven die-off is freq...

Fire is a major disturbance affecting forests worldwide with significant economic, social, and ecological impacts. The southernmost forests on Earth extend continuously along the Andes from mid-to subantarctic latitudes in South America. In this region, warming and drying trends since the mid-20th century have been linked to a positive trend in the...

Significance Fire is a key ecological process affecting ecosystem dynamics and services, driven primarily by variations in fuel amount and condition, ignition patterns, and climate. In the Southern Hemisphere, current warming conditions are linked to the upward trend in the Southern Annular Mode (SAM) due to ozone depletion. Here we use tree ring f...

1.Ecological memory, often determined by the extent and type of retained biological legacies present following disturbance, may produce persistent landscape patterns. However, after fire, the persistence or switch to an alternative state may depend on the complex interplay of ecological memory (biological legacies) and potential effects of new exte...

Drought events are increasing globally, and reports of consequent forest mortality are widespread. However, due to a lack of a quantitative global synthesis, it is still not clear whether drought-induced mortality rates differ among global biomes and whether functional traits influence the risk of drought-induced mortality. To address these uncerta...

Ongoing climate change poses significant threats to plant function and distribution. Increased temperatures and altered precipitation regimes amplify drought frequency and intensity, elevating plant stress and mortality. Large-scale forest mortality events will have far-reaching impacts on carbon and hydrological cycling, biodiversity, and ecosyste...

Resumen Los bosques cubren el 30 % de la superficie terrestre y contienen el 77 % de la biomasa viva. Estos ecosistemas en la Patagonia son un extenso reservorio de vida silvestre y un sistema con potencial productivo. Se sabe poco de cómo interactúan los efectos del manejo forestal y los cambios ambientales sobre los procesos de regeneración del b...

Tree mortality is a key factor influencing forest functions and dynamics, but our understanding of the mechanisms leading to mortality and the associated changes in tree growth rates are still limited. We compiled a new pan-continental tree-ring width database from sites where both dead and living trees were sampled (2,970 dead and 4,224 living tre...

El objetivo fue estudiar como las prácticas de manejo de bosque nativo (raleo) y las condiciones ambientales influyen en la folivoría sobre juveniles de especies arbóreas nativas de interés forestal. En un programa experimental de manejo en un matorral denso (Paraje El Foyel), se plantaron individuos de Austrocedrus chilensis, Nothofagus alpina, N....

El objetivo fue estudiar como las prácticas de manejo de bosque nativo (raleo) y las condiciones ambientales influyen en el desempeño de juveniles de especies arbóreas nativas de interés forestal y en la folivoría. En un programa experimental de manejo en un matorral denso (Paraje El Foyel), se plantaron individuos de Austrocedrus chilensis, Nothof...

Question The study of temporal variation of plant–plant interactions has received little attention despite its importance in community dynamics. Successional processes triggered by disturbances such as fire may be determined by changes in key interactions between dominant woody plants. Taking advantage of a 95‐yr‐old post‐fire natural experiment we...

Ecological disturbances triggered by earthquakes and volcanic eruptions are of fundamental importance in structuring the temperate forests of southwestern South America and New Zealand. We review studies of the ecological effects of these tectonic phenomena and how they have been central to progress in the modern development of forest ecology in bo...

In the context of global warming and increasing impacts of invasive plants and animals, we examine how positive fire–vegetation feedbacks are increasing the vulnerability of pyrophobic temperate forests to conversion to pyrophytic non-forest vegetation in southern South America and New Zealand. We extensively review the relevant literature to revea...

Ecological disturbances triggered by earthquakes and volcanic eruptions are of fundamental importance in structuring the temperate forests of southwestern South America and New Zealand. We review studies of the ecological effects of these tectonic phenomena and how they have been central to progress in the modern development of forest ecology in bo...

Fire severity and extent are expected to increase in many regions worldwide due to climate change. Therefore, it is crucial to assess the relative importance of deterministic vs. stochastic factors producing remnant vegetation to understand their function in the persistence of fire-sensitive plants. Vegetation remnants (areas within the landscape t...

In view of global climate change, it is important to understand the responses of tree species to climate changes in the past. Combinations of phylogeographic analysis of genetic evidence, coupled with species distribution models (SDMs), are improving our understanding on this subject. We combined SDMs and microsatellite data from populations of the...

Understanding fire spread in different ecosystems is of fundamental importance for conservation, management and anticipating the effects of environmental changes. Tailoring existing fire spread models to particular landscapes is challenging because it demands a substantial data collection effort. Here we develop an objective way to fit simple stoch...

In an earlier work, we found that 66% of manuscripts that suffered editorial rejections were finally accepted in journals of similar ranking to which they were originally submitted. We thus concluded that editors appear to be “poor oracles” with regards to being able to evaluate the quality of a manuscript without the help of external reviewers. Th...

Episodic mass flowering and subsequent die‐off of bamboo understories may generate rare opportunities for tree regeneration by altering consumer–seedling interactions as much as by increasing light availability to seedlings. We hypothesized that bamboo dieback interacts with canopy neighbourhood composition in creating recruitment microsites for tr...