The impact of fire intensity on plant growth forms in high-altitude Andean grassland

Abstract

16Fires in the páramo grasslands of the tropical northern Andes vary in intensity at the 17 landscape scale. Fire suppression strategies, intended to conserve biodiversity and páramo 18 ecosystem integrity and function, could lead to the accumulation of high fuel loads and 19 ultimately fires of higher intensity. Yet the impact of fire intensity on páramos is not well 20 studied or understood. 5½ years after a fire, we measured plant growth form composition, 21 light transmission to the ground and soil temperature in plots representing very high, high, 22 medium, and low fire intensities, plus a "control" that had been unburned for at least 40 23 years. We also assessed Espeletia rosette diameters, heights, population density, and 24 mortality. The low intensity plot, with a closed canopy of vegetation and lower growth 25 form diversity, contrasted with the very high intensity plot, with patchy vegetation cover 26 and higher growth form diversity. The high intensity plot had shorter Espeletia plants with 27 smaller rosettes. Light transmission to the ground increased with fire intensity, as did soil 28 temperatures. We demonstrate that the same fire can produce different 29 microenvironmental conditions, plant communities, and population structures in different 30 parts of the same fire event. In future, fire suppression could provoke more intense fires 31 with consequences for ecosystem function and service provision. Since intensity is 32 determined by a complex interaction of factors, we advocate a field programme of 33 experimental fires for a better understanding of páramo fire ecology and to guide effective 34 páramo conservation strategies. 35

Climate Vulnerability Assessment of the Espeletia Complex on Páramo Sky Islands in the Northern Andes

“…Last but not least, extending the modeling approach implemented in this work to other key pressures (e.g., fire, Wu and Porinchu, 2019;Rivadeneira et al, 2020;Zomer and Ramsay, 2020) and plant groups (Luteyn, 1999) in the Páramo, as well as to other sky islands around the mountains of the world (Hoorn et al, 2018;Pausas et al, 2018;Nürk et al, 2019;Testolin et al, 2020), and more broadly to other island-like systems (Papadopoulou and Knowles, 2015;Lamichhaney et al, 2017;Cámara-Leret et al, 2020;Flantua et al, 2020), will help understanding climate change effects on unrelated taxa experiencing similar evolutionary processes (Condamine et al, 2018;Cortés et al, 2020;Nürk et al, 2020). Such systems offer natural experiments to assess the role of colonization and adaptation (Ding et al, 2020;McGee et al, 2020;Tito et al, 2020) in the past and ongoing responses to climate change, which undeniably will complement ecological predictive modeling.…”

Physiognomic responses of páramo tussock grass to time since fire in northern Ecuador

“…Although the rapid inclusion of dead leaves in the first 2 y after fire contributes potential fuel to the next fire, it is the continued rise in tussock height that builds up much of the combustible material in later years. The presence of significant quantities of fuel not only increases the chances of fire spreading though the vegetation once it has started (Pels & Verweij 1992), it also increases the likelihood of a high-intensity fire, resulting in higher plant mortality and more damage to ecosystem services (Ramsay & Oxley 1996, Zomer & Ramsay 2020a). More frequent fires, with lower fuel loads, might be less damaging, and might even promote productivity (Hofstede et al 1995) and plant diversity (Bremer et al 2019, Keating 2007.…”

Post‐fire changes in plant growth form composition and diversity in Andean páramo grassland

“…Bremer et al (2019), Keating (2007) and Ramsay (2001) concluded that páramo vegetation recovery does not follow one particular successional trajectory. Fires can have very different effects on vegetation, depending on the intensity and extent of a particular fire (Luteyn, 1999; Sklenář & Ramsay, 2001; Suárez & Medina, 2001; Keating, 2007; Zomer & Ramsay, 2020). Fire behaviour is determined by the pre‐fire community structure (physical vegetation structure and fuel accumulation) and fire event conditions (Zomer & Ramsay, 2020).…”