Towards understanding the fossil record better: Insights from recently deposited plant macrofossils in a sclerophyll-dominated subalpine environment Giselle A. Astorga ⁎, Gregory J. Jordan, Timothy Brodribb School of Biological Sciences, University of Tasmania, Private bag 55, Hobart, Tasmania 7001, Australia abstract article info Article history: Received 27 January 2014 Received in revised form 20 June 2016 Accepted 23 June 2016 Available online 28 June 2016 Accumulations of plant macrofossils in lake sediments and other sedimentary deposits are increasingly being used to refine our understanding of past vegetation history, ecological processes and related climate conditions. However, past vegetation studies based on the use of disarticulated plant structures need to consider the specific potential for fossilisation of different species and different plant organs. Such knowledge is available for many systems, but the taphonomy of sclerophyll floras is very poorly known. To provide understanding of the taphonomic processes affecting the representation of sclerophyllous plant species in fossil assemblages this study investigated the potential source vegetation of plant remains extracted from modern sediments of a subalpine lake in Tasmania, southernmost Australia. It was found that the vast majority of the leaf types represented in the sediments belong to broadleaf sclerophyllous species living in close proximity to the lake, although the representation of species was not related to their values of leaf mass per unit area. Additionally, a bias between the abundance of species in the standing vegetation and the number of leaves of the same species in sediments was observed. Thus, small-leaved shrub species, such as many members of Ericaceae, produce comparatively many more leaves and tend to be over-represented in sediments. In contrast, even though, large-leaved tree species such as Eucalyptus and Nothofagus are dominant in the standing vegetation, they produce substantially fewer foliar organs per ground area of vegetation. Accounting for these discrepancies, we developed an intrinsic representativity index that provides a more accurate picture of the relationship between the leaf assemblages incorporated in the sediments and the abundance of these species in the source vegetation. © 2016 Elsevier B.V. All rights reserved. Keywords: Plant taphonomy Surface sediments Plant macrofossils Plant megafossils Megaflora Leaf assemblages Sclerophyll vegetation Representation 1. Introduction Evergreen sclerophyll floras are widely distributed around the world, especially in Mediterranean-type climates, where they represent the most diverse floras outside the tropics (Cowling et al., 1996). However, plant macrofossil evidence indicates that diverse sclerophyll floras existed under wet non-Mediterranean climates in the Cenozoic, and even as recently as the early Pleistocene, leading to questions about the link between sclerophylly and dry climates (e.g. Axelrod, 1975; Chen et al., 2014; Hill, 2004; Palamarev, 1989; Schnitzler et al., 2011; Sniderman et al., 2013). Plant taphonomic studies investigating the potential for fossilisation of different plant organs and species in sclerophyll-dominated environments may, therefore, have important implications for the interpretation of plant macrofossil records. However, there have been very few such studies. Accumulations of plant macrofossils (also known as megafossils) in different depositional environments, such as lakes or streambeds are used to refine our understanding of past vegetation history, ecological processes and related climate conditions (e.g. Allen and Huntley, 1999; Birks, 2001; Huntley, 2001; Collinson et al., 2010; Gee, 2005). However, plant macrofossil assemblages can only be validly interpreted in the light of the potential biases resulting from the differential preser- vation of different organs and species. The analysis of plant macrofossils from surface sediment samples, the recently deposited sediments in depositional environments such as lakes, can enhance the understand- ing of processes that determine the differential potential for fossilisation (Dieffenbacher-Krall and Halteman, 2000; Dieffenbacher-Krall, 2007; Spicer and Wolfe, 1987). The potential for fossilisation in plants may vary depending on both intrinsic and extrinsic factors (Martin, 1999; Spicer, 1991). In particular, intrinsic factors or individual characteristics of plant organs (e.g. the Review of Palaeobotany and Palynology 233 (2016) 1–11 ⁎ Corresponding author at: School of Biological Sciences (Life Science Building), University of Tasmania, Private Bag 55, Hobart, TAS 7001, Australia. E-mail addresses: Giselle.Astorga@utas.edu.au (G.A. Astorga), Greg.Jordan@utas.edu.au (G.J. Jordan), timothyb@utas.edu.au (T. Brodribb). http://dx.doi.org/10.1016/j.revpalbo.2016.06.004 0034-6667/© 2016 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Review of Palaeobotany and Palynology journal homepage: www.elsevier.com/locate/revpalbo