The Use of Plant Macrofossils for Paleoenvironmental Reconstructions in Southern European Peatlands

Abstract

The analysis of plant macrofossils in peatland ecosystems has been widely used for the climatic and ecological reconstruction of the Holocene in the high latitudes of the northern hemisphere. By contrast, perhaps associated with rarity of these ecosystems, this proxy has barely been explored for southern Europe. In this work, a compilation and review of existing knowledge on the study of plant macrofossils of peatlands in southern Europe has been carried out, both from a paleoenvironmental perspective and in terms of biodiversity dynamics. Although small in surface area, the peatlands of southern Europe stand out for their diversity (botanical, edaphogenic, morphological, etc.), which has allowed the recovery of a large number of macrofossils from both vascular plants and bryophytes. The southern zone of Europe contains refuge zones with a high plant diversity that have not suffered the intense glaciation of the northern zones, this allows a continuous record since the beginning of the Holocene and the detection of climatic events in lower latitudes, where the ice recession was earlier.

Experimental waterlogging of grape seeds, impact on seed shape and geometrical reversing for morphometric inference

“…It is difficult, not to say impossible, to experimentally reproduce long-term decay of waterlogged plant remains (Hall and Kenward, 2004). Simple chemical degradative treatments can nevertheless be used to mimic the alterations and changes that may have occurred in sedimentary deposits (Mösle et al, 1997;Souto et al, 2016). In this study, we test the effect of four chemical treatments mentioned in the literature to artificially fossilize plant organs or to facilitate sieving of clay soils but causing an impact on the preservation of waterlogged macro-remains .…”

“…Four chemical products, with their associated concentration values and heating conditions, were selected based on the literature (Fig 2 ): 1) 30% Hydrogen peroxide (H2O2) with Acetic acid glacial (C2H4O2) 1/1, heated at 40°C (Mösle et al, 1997), 2) 65% Nitric acid (HNO3) (Kerp, 1990), 3) 10% Potassium hydroxide (KOH), heated 40°C (Vandorpe and Jacomet, 2007), 4) 8% Sodium hydroxyde (NaOH), heated 40°C (Souto et al, 2016). For each chemical, the seeds were soaked in 5 ml of solution in individual beakers for increasing times.…”

Pastoral Stone Enclosures as Biological Cultural Heritage: Galician and Cornish Examples of Community Conservation

“…Nevertheless, the process of In moist, acidic peaty soils in both regions, vegetation originally developed as wet heaths and bogs with Calluna vulgaris, Erica tetralix, and Erica ciliaris, in a mosaic with Sphagnum and Cyperaceae/Poaceae wet grassland communities. This type of mixed formation has been reconstructed through the Holocene with pollen data and plant macrofossils in peatlands of north-western Iberia and south-western Great Britain [22,23]. Plant macrofossils allow a good reconstruction of the local vegetation at different temporal layers, and when this information is combined with information from charcoal remains the prevailing communities can be identified in relation to putatively anthropic burning [24].…”

“…Nevertheless, the process of vegetation turnover in heathlands is complex and can differ significantly between regions. Whereas in Galicia, Molinia caerulea, and Agrostis curstisii grassland have been historically a relevant constituent of peatland and wet heath systems [23], vegetation reconstruction in some British moors do not follow this pattern and peatlands have revealed a late relevance of Molinia caerulea, with a clear prevalence only after the industrial revolution [26]. Therefore, agents other than traditional grazing and burning have to be invoked as responsible, like increased atmospheric input and/or changes in grazing pressure [25].…”

Diatoms in Paleoenvironmental Studies of Peatlands

“…In paleoenvironmental studies of peatlands, macroscopic plant remains and pollen are generally considered the best tracers among the different biological proxies preserved in peat because changes in vegetation are directly related to the formation of peat [18], and they are widely used in peatlands of Southern Europe [19][20][21][22]. Thecamoebians are also a common indicator often associated with Sphagnum: They are more sensitive to water conditions and show a faster response to environmental changes than vegetation [23,24].…”