CEMFOR SEMINAR – Pere Casals
Speaker: Pere Casals (CTFC-CEMFOR)
Title: Understory woody resprouting strategies after prescribed fires
Abstract: The capacity of a plant species to resprout after destruction of most of its aboveground biomass is an important trait for its persistence. However, different mechanisms may operate at different levels after fire to reestablish individuals from each species and better compete for the acquisition of resources. trade-offs between growth investment for better light acquisition and resource allocation for resisting additional stress, such as recurrent fires, browsing or insect injuries, may determine the exit of some species over others short-term after underburning. Tacking advantage of the richness of functional traits of Mediterranean forest understory, this study aims to discuss the expression of different plant functional traits on the resprouting vigor after prescribed underburning in relation to the specific characteristics of shrub individuals, microsite light availability, and intensity and season of fire.
At individual level, in addition to pre-fire shrub size, light availability seems to be a strong driver of resprouting vigor three years after underburnings. Bark investment index at the species level contributes to explain the performance of resprouts. Hence, leaf area, specific leaf area and bark investment are inter- and intraspecific traits clearly related to the expression of resprouting vigor. At plot scale, the number and performance of resprouts of the studied shrub species were lower in fall burns than in spring ones. As a conclusion, our study suggests that the phenological and physiological status of shrub individuals went the perturbation occurs may be crucial for its reestablishment. This knowledge may assist in the decision-making process for the management of understory forests in relation to site characteristics and plant composition and structure.
CEMFOR SEMINAR – Aleksi Lehikoinen
Speaker: Aleksi Lehikoinen (University of Helsinki)
Title: : Abundance changes of birds in Europe: impact of climate, land use and life histories
Abstract: Climate change has suggested to shift species distribution areas towards north, but also other anthropogenic factors can influence population. In this presentation, I show examples based on long-term monitoring how abundances of bird species have changed in relation to climate change, species habitat preferences and human land use. In addition, we have also investigated can protected areas mitigate impacts of climate change. Since many bird species are migratory it is important to investigate changes during both breeding and wintering season. One of the strongest climate driven changes are the shifts in wintering abundances of waterbirds. I also present preliminary results where changes in wintering bird communities in relation to climate change have been studies across Europe from Catalonia to Finland.
CEMFOR SEMINAR – Kate Giljohann
Speaker: Kate Giljohann (University of Melbourne, Australia)
Title: A demographically effective measure of population size for disturbance-prone ecosystems
Stochastic disturbances, such as fire, are important in many ecosystems. Disturbances can drive population dynamics; stimulating large changes in population size and structure. Understanding how population structure at one point in time influences future population size is key to making realistic estimates of population changes in disturbance-prone ecosystems. Yet how population structure interacts with disturbance regimes is rarely considered in conservation management.
A useful theory to account for the influence of population structure on future population size is the stochastic equivalent ratio. However, it is unclear whether this theory applies when stochasticity is large, such as in fire-prone environments.
Using a population model for a fire-killed obligate seeder from semi-arid Australia, I explore the utility of the stochastic equivalent ratio and ask, can the ratio: i) indicate the potential for future population growth? ii) identify appropriate fire regimes? and iii) estimate the abundance of seedlings that will emulate the trajectory of a reference population?
The method I evaluate, and then generalize, has wide applicability and great potential for achieving future plant and animal population goals when stochastic disturbances drive population dynamics.
CEMFOR SEMINAR – Pablo Cruz
Speaker: Pablo Cruz (Universidad Mayor de Chile).
Subject: Exploring collaboration between CTFC and UMayor-Oterra
OTERRA es un centro de estudios de recursos naturales perteneciente a la escuela de ingeniería forestal de la U. Mayor. Posee 9 investigadores tiempo completo, laboratorios y equipos propios y sus actividades se financian con fondos externos a la Universidad, tanto del sector público como privado.
R workshop – Aitor Ameztegui
Organizer: Aitor Ameztegui (CTFC-CREAF)
Title: Using packages ‘tidyr’ and ‘dplyr’
CEMFOR SEMINAR – Antoine Cabon
Speaker: Antoine Cabon (Ph.D. student, CTFC-CREAF)
Title: The ecohydrological equilibrium hypothesis allows quantifying the soil water supply of drought prone forests.
Abstract: In water-limited ecosystems, such as Mediterranean ones, the amount of water plants can access (i.e. the Soil Water Supply, SWS) is a key determinant of forest demography (e.g. tree growth and mortality) and function (e.g. water and carbon fluxes).
Although the link between soil moisture (θ) and soil water extractability by plants can be modelled through pedotransfer functions, the estimation of SWS is limited by the difficulty to measure the plants rooting depth (Z) and their Fine Roots Distribution (FRD) in the soil profile.
Here we estimate Z and FRD for different forest plots located in Catalonia (Northeast Spain), where θ or transpiration (E, approached by
sap flow measurements) observations were available, using simplified representation of plant hydraulics and the Eco-Hydrological Equilibrium (EHE) hypothesis. We assume that forest stands conform to this hypothesis and that their root system is therefore optimized in order to maximize transpiration within the limits of acceptable drought stress, characterized using species-specific critical levels of leaf water potentials (ψ).
We simulate ψ, E and θ for different combinations of Z and FRD with a simple water balance model and use the simulations to approach the local actual values of Z and FRD by 1) hypothesizing optimized species root system and by 2) calibrating our model against E or θ observations. Estimates from both methods were in close agreement when water was a most limiting factor, therefore sustaining our initial hypothesis.
Our method has the potential to palliate the lack of data concerning the root system of drought prone forests using only information on stand structure and plant hydraulic properties and could therefore enhance the modelling of water fluxes at large spatial scales.
CEMFOR SEMINAR – Aitor Ameztegui
Speaker: Aitor Ameztegui (Marie Curie fellowship, CREAF)
Title: Managing stand density to enhance the adaptability of Scots pine stands to climate change: a modelling approach
Abstract: La mayoría de los modelos climáticos para la región mediterránea predicen periodos de sequía más frecuentes e intensos, que pueden afectar al crecimiento y mortalidad de los árboles en amplias zonas de su distribución actual. Uno de los tratamientos selvícolas que se baraja para mitigar los impactos del cambio climático es reducir la densidad de arbolado mediante claras. Sin embargo, aún no está claro cómo responderán las masas forestales a diferentes regímenes de claras en función del escenario climático, ni conocemos bien la dinámica post-clara del balance hídrico. En este estudio exploramos estos aspectos para masas de pino albar (Pinus sylvestris) mediante modelización, acoplando un modelo de dinámica forestal con un modelo mecanístico de humedad del suelo y estrés hídrico. Nuestros resultados muestran la existencia de trade-off entre el incremento de productividad y la ganancia en disponibilidad hídrica provocada por las claras. Además, dichos mecanismos dependen de la estación y el clima, por lo que no sería recomendable aplicar recetas generalistas sin tener en cuenta estos factores.
CEMFOR SEMINAR – Miquel De Cáceres
Speaker: Miquel De Cáceres (CTFC/CREAF)
Title: Estimating daily meteorology at the landscape scale: The R package ‘meteoland’
Abstract: Reliable meteorological data are a basic requirement for hydrological and ecological studies at the landscape scale. Given the large spatial variation of topographic features in complex reliefs, meteorological records from a single weather station are often not representative of entire landscapes. Moreover, studies addressing the impacts of climate change on forests and landscapes require downscaling coarse-scale predictions of climate models to the landscape scale. With the aim to assist research of climate impacts on forests, the R package ‘meteoland’ provides utilities to estimate daily weather variables at any position in complex terrains:
- Spatial interpolation of daily weather records from meteorological stations.
- Statistical downscaling of coarse-scale meteorological data to the landscape scale.
In this seminar I will overview the data structures, functions and procedures of the R package ‘meteoland’ using the Solsonès county as study area.
CEMFOR SEMINAR – Maria Triviño
Speaker: Maria Triviño (Univesitat de Jyväskylä, Finlàndia)
Title: Optimizing management to reduce trade-offs between multiple objectives in boreal production forests
Abstract: I will give first an overview of the work carried out at the Boreal Ecosystems Research Group (http://bit.ly/B_E_R_G). Then, I will present the results of one of the studies where we are applying multiobjective optimization to find the optimal combination of forest management regimes that provide as high levels as possible of (i) timber harvest revenues, (ii) carbon storage and (iii) suitable habitat for a number of key boreal species.
Integrating ecological models to secure the future of biodiversity across flammable continents
Speaker: Luke Kelly Resum: Fire is a natural process that shapes ecosystems worldwide. However, the frequency of fires has been modified by climate change and population growth, and inappropriate fire regimes threaten biodiversity in Australia and the Mediterranean Basin. There is an urgent need to predict the responses of biodiversity to future fires. I will present a brief overview of my work on optimal fire histories for biodiversity conservation using case studies from Australian shrubland and forest ecosystems. I will also outline some of the work I am planning with collaborators at the CTFC and CREAF with a focus on Mediterranean ecosystems. This includes developing a suite of models and tools that will enhance our capacity to design and evaluate alternative fire management strategies in Australian and Mediterranean landscapes. Finally, and perhaps most importantly, I will be answering the question ‘Why is there an Australia living in Solsona?”.