Vegetation reconstruction from soil phytoliths, Tongariro National Park, New Zealand

Abstract

Phytoliths are microscopic particles of opaline silica (SiO 2 .nH 2 O) formed by the accumulation and solidification of siliceous gel between and within the cells of many plants. Soil surface phytolith assemblages are assessed for their potential to accurately reconstruct the overlying vegetation community within the subalpine zone of Tongariro National Park, New Zealand. The results provide important new evidence that phytoliths are an under-exploited tool for reconstructing past vegetation patterns. A new technique has been developed to quantitatively compare phytolith supply with accumulation. From four study sites, plants and soil were collected for phytolith extraction, and vegetation height and canopy cover were surveyed. The results indicate that at three of the four sites, source vegetation could be satsifactorily reconstructed at a broad community level from the dispersed soil phytolith record implying similar expectations for the application of this technique to the fossil phytolith record.

New Zealand sub-Antarctic phytoliths and their potential for past vegetation reconstruction

“…The grassland interpretation for the quadrats in this study is only really applicable to that at CLS with a 70% grass canopy cover. This overall result reflects a previous observation during a similar study at Tongariro National Park, central North Island, New Zealand, that the presence of grass in the source vegetation is likely to be over-represented in general, and the proportion of grasses in the source vegetation association cannot be estimated from the dispersed phytolith assemblage alone (Thorn 2006).…”

“…To compare the vegetation and underlying soil phytoliths, overall phytolith production of the vegetation within each quadrat has to be in the form of a list of morphotype proportions reflecting the species canopy cover, phytolith production rate and preservation potential. This is achieved by weighting the proportion of each morphotype from each phytolith-producing species using the following formula (Thorn 2006):…”

Soil and plant phytoliths from theAcacia-Commiphoramosaics at Oldupai Gorge (Tanzania)

“…Phytogenic silica is released into soils after litter decomposes and discharges both amorphous silica and phytoliths. This process creates a synchronous phytolith record of the plant communities that grew in the soil (Piperno & Becker, 1996; Kerns, Moore & Hart, 2001; Clarke, 2003; Piperno, 2006; Thorn, 2006; Honaine, Zucol & Osterrieth, 2009; Morris, Ryel & West, 2010; Mercader et al, 2011; Novello et al, 2012; Novello et al, 2018; Blinnikov, Bagent & Reyerson, 2013; An, Lu & Chu, 2015; Watling et al, 2016; Esteban et al, 2017; Fick & Evett, 2018).…”

Soil and Plant Phytoliths from the Acacia-Commiphora Mosaics at Oldupai Gorge (Tanzania)

“…Phytogenic silica is released into soils after litter decomposes and discharges both amorphous silica and phytoliths. This process creates a synchronous phytolith record of the plant communities that grew in the soil (Piperno and Becker, 1996;Kerns et al, 2001;Clarke, 2003;Piperno, 2006;Thorn, 2006;Honaine et al, 2009;Morris et al, 2010;Mercader et al, 2011;Novello et al, 2012Novello et al, , 2018Blinnikov et al, 2013;An et al, 2015;Watling et al, 2016;Esteban et al, 2017;Fick and Evett, 2018).…”