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

Abstract

Phytoliths in the modern vegetation of sub-Antarctic Campbell Island are compared with those in the soil beneath to assess the accuracy of vegetation reconstructions made from dispersed phytolith assemblages. The soil phytoliths alone suggest the source vegetation is a grassland association for all study sites, which reflects none of the herb, fern or shrub component of the overlying vegetation. It is concluded that at this locality dispersed phytoliths on their own are not reliable indicators of source vegetation and should be used with caution in this context for palaeoecological studies. However, they can provide useful botanical information where all other organic material is absent. With further research, based on the abundance and diversity of Poaceae phytoliths observed in this and other studies, dispersed phytoliths from the fossil record have the potential to contribute significantly to the understanding of grassland ecosystem development in the geological past.

Poaceae phytoliths from the Niassa Rift, Mozambique

“…This scarcity is in contrast with the long-standing investigations of silica bodies among the European grasses; dating as far back as the late 19th and 20th centuries (see review of early work in Parry and Smithson, 1964). In other parts of the world, the phytoliths extracted from living Poaceae have been subjected to qualitative and quantitative analysis; for example, in South East Asia (Whang et al, 1998;Lu and Liu, 2003a), India (Krishnan et al, 2000), Western Melanesia (Boyd et al, 1998), the New Zealand grasslands (Marx et al, 2004;Thorn, 2004Thorn, , 2008, the European Atlantic zone, as well as the Alpine and Mediterranean regions (Parry and Smithson, 1964;Ollendorf et al, 1988;Kaplan et al, 1992;Carnelli et al, 2004;Tsartsidou et al, 2007). Grass reference collections have also been developed in North America (Blackman, 1971;Brown, 1984;Fredlund and Tieszen, 1994;Blinnikov, 2005), the Neotropics (Piperno and Pearsall, 1998) and South America (Zucol, 1998;Iriarte, 2003;Gallego and Distel, 2004;Fernández Honaine et al, 2006).…”

Soil phytoliths from miombo woodlands in Mozambique

“…According to oral information and photographic records dating back less than 50 years ago, we notice the strongest disagreement between reconstructed and actual vegetation cover (Fig. 5) (see Fredlund and Tieszen, 1994;Thorn, 2008) for parts of the landscape that were subjected to severe anthropogenic modification in the recent past. Contrarily, there is agreement for loci that have supported stable biomes for the last few decades.…”

Taxonomic and biogeographical analysis of diatom assemblages from historic bryophyte samples from Campbell Island (sub-Antarctic)

“…The island is an eroded remnant of extensive Oligocene to Miocene basaltic volcanism (Quilty 2007) and is covered with large peat deposits, up to 10 m thick (Rainsley et al 2019). A cloudy, moist, and cool climate prevails with minimal sunshine (Thorn 2008). The island has a total surface of 113 km 2 and reaches an elevation of 569 m. More details on the climate, geomorphology, and vegetation of the island can be found in Saunders et al (2015).…”