Centros UC
Permanent URI for this community
Browse
Browsing Centros UC by browse.metadata.categoriaods "15 Vida de ecosistemas terrestres"
Now showing 1 - 2 of 2
Results Per Page
Sort Options
- ItemA numerical model for linking soil organic matter decay and wildfire severity(2021) Aedo Quililongo, Sebastián Alejandro; Bonilla Meléndez, Carlos Alberto; CEDEUS (Chile)Wildfires are a critical phenomenon in terrestrial ecosystems, and the intensity and frequency of these events have increased in recent years. High temperatures in the topsoil during wildfires can induce changes in soil physical, chemical, and biological properties due to the loss of soil organic matter (SOM). Therefore, the main objective of this study was to develop a numerical model to predict SOM decay during wildfire events. The model identifies the main parameters controlling SOM decay and predicts its decline by coupling the energy balance for soil heating and species conservation for water and SOM using high temperature-induced vaporization and combustion kinetics. Fluid flow was not included; however, the radiative energy conducted through soil pores was incorporated as a volumetric pore radius function. When the radiative term in the thermal conductivity was not considered, the model predicted the soil thermal evolution with a determination coefficient r(2) > 0.91 and with an r(2) > 0.98 when the volumetric pore radius was adjusted. The main parameters controlling SOM decay were soil texture, oxygen availability, and initial soil water and SOM contents. SOM decay was also dependent on the wildfire temperature and exposure time. In terms of soil texture, SOM decay increases as sand increases or clay reduces. The main results showed that the soil water content controlled the amount of heat consumed during vaporization, the normalized SOM decay does not depend on the initial SOM content, and the restricted oxidation limited SOM decay. Finally, this study reduces the number of parameters when studying SOM decay and second-order fire effects for post-fire assessment and restoration. Also, because it provides a better understanding of how wildfires affect SOM, implemented as an additional routine, the model can enhance other existing computer models for describing ecological processes.
- ItemA “landscapes of power” framework for historical political ecology: The production of cultural hegemony in Araucanía-Wallmapu(2020) Escalona Ulloa, Miguel; Barton, Jonathan R.; CEDEUS (Chile)The region of Araucania, since its incorporation into the Republic of Chile, has been subject to significant territorial transformations. The Chilean State, supported by economic elites, the political class, and intellectuals have all contributed to the discursive positioning of, and the creation of artefacts in, this regional space. These devices for mobilising power have enabled an appropriation of nature – through natural resource exploitation – and an appropriation of land rights through property titles. The occupation of Araucania from the end of the 19th century was achieved principally through the artefacts of larger settlement consolidation, the railway network, and the building of roads. These were designed and imposed from Santiago through political and administrative channels based on an internal colonialism logic. Conflicts with indigenous Mapuche in Wallmapu (the Mapudungun name for their territory) arose as a consequence of asymmetries of power and this appropriation of space, including expulsion from their land, deforestation, increasing poverty due to restricted access to traditional resources, and epistemic violence through specific constructions of development and the subalterning of indigenous “others.” This historical political ecology not only reveals the expanding frontiers of extractivism and processes of accumulation in favour of national political and economic elites, but more importantly shows how the construction of cultural landscapes became a device for exercising power and justifying appropriation in pursuit of modernity, progress, and development. These landscapes of power evolved over time as different demands were placed on this territory: first as a wheat bowl, and second as forestry plantation. A “landscapes of power” framework is presented in order to work through these constructions of landscape, building on phenomenological and dwelling perspectives in order to focus on the role of cultural hegemony and power relations. The information, practices and views in this article are those of the author(s) and do not necessarily reflect the opinion of the Royal Geographical Society (with IBG).