Reconstruction of fire regimes through integrated paleoecological proxy data and ecological modeling

Abstract

Fire is a key ecological process affecting vegetation dynamics and land cover. The characteristic frequency, size, and intensity of fire are driven by interactions between top-down climate-driven and bottom-up fuel-related processes. Disentangling climatic from non-climatic drivers of past fire regimes is a grand challenge in Earth systems science, and a topic where both paleoecology and ecological modeling have made substantial contributions. In this manuscript, we (1) review the use of sedimentary charcoal as a fire proxy and the methods used in charcoal-based fire history reconstructions; (2) identify existing techniques for paleoecological modeling; and (3) evaluate opportunities for coupling of paleoecological and ecological modeling approaches to better understand the causes and consequences of past, present, and future fire activity.

Soil or fire: what causes treeless sedgelands in Tasmanian wet forests?

“…Of critical importance is the reconstruction of fire regimes in time and space (Conedera et al 2009;Iglesias et al 2015) and convincingly linking fire and vegetation change (e.g., McWethy et al 2010McWethy et al , 2014. Such reconstructions may include Holocene sedimentary cores (e.g., Behling and Hooghiemstra 2000), analysis of macro subfossil wood or charcoal in soils (e.g., Kellman 1975), geochemical proxies of vegetation types, such as carbon stable isotopes (e.g., Magnusson et al 2002) and dendrochronological analysis of fire scars across multiple scales (Falk et al 2011).…”

Forest fires in Dalmatia

“…Deposits of charcoal present a valuable source of information due to the mechanism of their formation during incomplete combustion of fuel in reduced conditions. Pieces of charcoal are dispersed in wildfires and deposited in lakes, where they form sediments which are preserved until the present day (Iglesias et al, 2015). Natural causes (lightning, volcanic eruptions) of wildfires are common in many parts of the world and are an integral part of many ecosystems, but 0.6 -4% of all burned areas in the Mediterranean were caused by lightning, making it the primary cause (Naveh, 1975).…”

“…We obtain data about wildfires from numerous sources like geochemical processes, layers of charcoal, growth rings on stumps, and archaeological sites (Iglesias et al, 2015). Deposits of charcoal present a valuable source of information due to the mechanism of their formation during incomplete combustion of fuel in reduced conditions.…”

Changing Fire Regimes in Tropical and Subtropical Australia

“…Contextual information about contemporary fire regimes has been provided from historical analysis of charcoal from sediment (Hantson et al 2016) however integration between paleoecology and ecological modeling is needed to understand climate-vegetation-humanfire linkages (Iglesias et al 2014). Macro charcoal analysis is not without its limitations, as for example charcoal fragments are derived from wood that has undergone incomplete combustion, and any successive fires are likely to have burnt charcoal deposits in the soil, thus removing records of previous fire events at the local scale (Waito et al 2015) Fire intensity will also have potential effects of differential wood combustion on the different taxon (Godwin and Tansley 1941).…”

“…Therefore integration between paleoecology and ecological modeling is needed to understand climate-vegetation-human-fire linkages (Iglesias et al 2014). Uncertainty over the nature and extent of change to fire regimes and in particular fire frequency and intensity creates challenges for managing ecosystems that have altered structure and function under climate change (Colloff et al 2016).…”