Tracking fire activity and post-fire limnological responses using the varved sedimentary sequence of Lake Jaczno, Poland

Abstract

Long-term paleofire perspectives provide key information on natural and human-derived land cover changes. The last few millennia are crucial to understanding the future of wildfire threats, since the increasing global temperatures are expected to have an impact on regions previously assumed to not be endangered. In this study we investigate the interplay between changing climatic conditions, land cover transformation, fires, and human activity based on the first 1750-year-long macrocharcoal record derived from varved sediments of Lake Jaczno, located in northeast Poland. The study is supported by macrocharcoal morphotype analysis, pollen and historical data, and statistical analysis, which revealed that in the vicinity of the lake both low- and high-intensity fires may have occurred. Most of them were set by humans, but in some periods biomass burning was favored by droughts or even derived by natural causes (i.e. lightning). Human-induced fires are especially evident between AD 1081 and 1283. This period corresponds to the peak activity of the Jatvings tribe in the region and the related deforestation for agrarian purposes. Fire combined with human activity and deforestation in the area impacted the limnological processes increasing primary productivity and shifts in water mixing regime.

Human-induced fires and land-use change in Lubusz Land (western Poland) derived from Lake Lubińskie sedimentary record

“…However, the intensification of animal husbandry and land transformation from forested areas to meadows and pastures, led to increased landscape openness. A similar pattern of open vegetation spread and increased indications of pine during this same time was observed in other Polish regions, as for instance in the regions of Greater Poland (Czerwiński et al, 2021; Lamentowicz et al, 2020; Pleskot et al, 2022), Masurian Lakeland (Bonk et al, 2016; Wacnik et al, 2014, 2016), and in the areas around Suwałki (Bonk et al, 2022; Kinder et al, 2019; Marcisz et al, 2020). Pawski Ług (Lamentowicz et al, 2020) and nearby Lake Lubińskie experienced a collapse of broadleaved tree species, evidencing the destruction of the natural deciduous forests residues at the beginning of the 1400s.…”

“…This is due either to the assumed low flammability of the vegetation or to past weather and climatic conditions not being conducive to ignition and spread of fire (Adámek et al, 2015). Meanwhile, more and more studies show that fire has been an integral part of the vegetation transitions and was involved in shaping European ecosystems throughout the Holocene (Bonk et al, 2022;Carter et al, 2018;Dietze et al, 2018Dietze et al, , 2019Kołaczek et al, 2016Kołaczek et al, , 2020Marcisz et al, 2015Marcisz et al, , 2017. This is because of frequent droughts and dominating air masses during the early Holocene and accelerated human evolution after 8500 cal.…”

A novel multiproxy approach to detect the impact of charcoal production on the natural environment in NW Poland – project concept and preliminary results

“…Biogenic sediments as a source of knowledge about the past Peat and lake sediments are considered archives of past environmental changes all around the world. Therefore, high-resolution palaeoecological analyses of biogenic sediments are increasingly becoming common (e.g., Brauer & Casanova, 2001;Marcisz et al, 2015;Lamentowicz et al, 2016;Słowiński et al, 2016;Łuców et al, 2021;Bonk et al, 2022). Tobolski (2000) stated that ecological issues, especially paleoecological ones, devoted to Poland's lake and peat bog ecosystems are little known.…”

“…All these environmental components are interconnected and interact with each other indirectly and directly, as well as in a cascading manner (e.g. Słowiński et al, 2018;Lamentowicz et al, 2019;Słowiński et al, 2019;Szewczyk et al, 2021;Bonk et al, 2022). We will use the archives such as peat, gyttja and soils.…”

Multidimensional tracking and consequences of the usage of forest products in Early Modern Poland

“…Human activity associated with the acquisition of material for construction and land for cultivation may also lead to deforestation (Dietze et al 2019;Słowiński et al 2019). These mechanisms have occurred alternately in the long postglacial history of vegetation in the European Lowlands and are crucial not only because a large portion of forest is lost but also because they have led to new processes, such as increased physical and chemical denudation, i.e., intensi cation of slope processes, changes in meso-climatic and microclimatic conditions, and modi cation of surface runoff (Dietze et A high-resolution analysis can be performed on biogenic cores (peat and lake sediments), as these are natural archives providing information on how ecosystems responded to changes in land use, deforestation, or drainage (Bonk et al 2022;Łuców et al 2020;Mroczkowska et al 2021;Słowiński et al 2018). Additionally, they can indicate the duration of these changes, and also explain whether these changes were related to natural phenomena or human activity that transformed the forest areas into cultivation elds (Czerwiński et al 2021;Słowiński et al 2021).…”