This is a pre-copyedited, author-produced PDF of an article accepted for publication in J. Anthropol. Archaeol. following peer review. The version of record Field, J.H., et al. Human-environment dynamics during the Holocene in the Australian Wet Tropics of NE Queensland: A starch and phytolith study. J. Anthropol. Archaeol. (2016), http://dx.doi.org/10.1016/j.jaa.2016.07.007 is available online at: http://www.sciencedirect.com/science/article/pii/S0278416516300721

Human-environment dynamics during the Holocene in the Australian Wet Tropics of NE Queensland: A starch and phytolith study Judith H. Field a, Lisa Kealhofer b, Richard Cosgrove c, Adelle C.F. Coster d a School of Biological, Earth and Environmental Sciences, The University of New South Wales, 2052 NSW, Australia, Corresponding author. E-mail address: [email protected] b Dept of Anthropology and Environmental Studies and Sciences, Santa Clara University, 500 El Camino Real, Santa Clara, CA 95053, USA c Archaeology Program, School of Humanities, La Trobe University, Melbourne, Victoria 3086, Australia d School of Mathematics & Statistics, The University of New South Wales, 2052 NSW, Australia

Keywords: Australia Rainforest Archaeology Holocene Phytoliths Ancient starch Niche construction

Abstract The timing and nature of hunter-gather exploitation of tropical rainforests is a topic of ongoing debate. In contrast to most other tropical regions, permanent settlement in Australian rainforests developed much later, and in the absence of adjacent agricultural economies. Here we explore how the tropical rainforests of northern Queensland were exploited during the late Holocene through an ancient starch and phytolith record spanning the last 2000 years. Sequences at the two sites under study – Urumbal Pocket (a ‘Eucalyptus pocket’ surrounded by rainforest) and Goddard Creek (within the rainforest) – indicate a human presence since the early Holocene, coincident with the re-establishment of rainforest in the region. Toxic starchy nuts and the associated complex processing underpinned permanent settlement. Using a geometric morphometric approach to starch analysis, a range of economic starch producing plant species were identified including Endiandra palmerstonii, E. insignis, Lasjia whelani and Beilschmiedia bancroftii in the Urumbal pocket sequence. The phytolith record shows that Urumbal Pocket has been a ‘Eucalyptus pocket’ for at least the last 2000 years, the open nature of the vegetation maintained by regular burning. Goddard Creek, on the other hand has been closed forest, with a changing profile as fire was used more frequently over time. The starch and phytolith sequence provide a unique insight into the local history of these rainforest archaeological sites, with a record that can be viewed against the backdrop of regional sequences documenting climatic and environmental patterns during the late Holocene.

1. Introduction Humans arrived in Sahul (Pleistocene Australia-New Guinea landmass) around 50,000 years ago and rapidly dispersed across the continent, entering most environmental zones within a few thousand years (O’Connell and Allen, 2012, 2015). A wide-ranging Pleistocene human presence has been documented, extending from the more arid regions of Sahul to the peri-glacial environments of south-western Tasmania and the montane valleys of New Guinea (Cosgrove, 1995; O’Connor, 1995; Cosgrove and Allen, 2001; Smith, 2006; Summerhayes et al., 2010; David et al., 2011). Denham et al. (2009: 38) have argued that it was a ‘generalist set of practices tailored to different regions and biotic resources’, perhaps developed in SE Asia (see Niah Cave: Barker et al., 2007), that equipped people to rapidly adapt while moving into and through these new landscapes.

Where rainforests were widespread during the Pleistocene, such as northernmost Sahul and offshore islands, a human presence is also found (Pavlides and Gosden, 1994; Summerhayes et al., 2016). Palaeoenvironmental data for other parts of northern Sahul (present day North Queensland) indicates significant tropical rainforest contraction and fragmentation over the last 50,000 years. The dramatic decline in tropical rainforest may have precluded the development of rainforest cultures prior to the Holocene (see Kershaw, 1983, 1986, 1993, 1994; Nix, 1991; Hopkins et al., 1993, 1996; Kershaw et al., 2007). Opportunities for exploitation of any of the rainforest resources by people would have centered on highly contracted distributions – in some places confined to gullies and other sheltered locales.

It is evident that a primary consideration in the timing and mode of rainforest settlement in Australia is the impact of global climatic change through the terminal Pleistocene and early-mid Holocene periods. An understanding of how major changes in the composition, configuration and range of tropical forests unfolded (Schneider and Moritz, 1999) will necessarily be an important factor in determining how people responded to change, and how they exploited these regions through this transitional period. We are constrained, to some extent, in answering these questions by the small number of archaeological sites known from the rainforest and the limitations of the data preserved therein (Ferrier, 2015).

Recent archaeological investigations in NE Queensland have identified the presence of people in the sclerophyll forests (adjacent to modern tropical rainforests) before and after the Last Glacial Maximum. While a human presence in the tropical rainforest is coincident with their re-establishment in the early Holocene, intensive use of the rainforest and permanent settlement by people does not emerge until c. 2000 years ago (Cosgrove et al., 2007). The apparent late development of rainforest cultures in Australia may be due to a complex interplay of factors. These include: 1. the pace of increases in population density across the region in the Holocene, which may have driven the need for access to more reliable resources; 2. the development of technologies facilitating exploitation of rainforest resources such as toxic starchy tree nuts (Cosgrove and Raymont, 2002); and/or 3. climatic constraints on tropical rainforest size and distribution during the Pleistocene-Holocene transition (see Bell et al., 1987; Kershaw, 1994; Kershaw et al., 2007 for climatic data).

In the 1980s Bailey and Headland (Headland, 1986; Bailey et al., 1989; Headland and Reid, 1989) argued that forest dwellers depended on exchanges/interactions with agriculturalists and horticulturalists outside the rainforest to counter the lack of resources therein. The implication was that people did not use tropical rainforests prior to the Holocene. Recent findings of Pleistocene rainforest occupation elsewhere in the world, often independent of subsistence patterns outside these habitats, contradict these controversial ideas, and suggest that where rainforests were present so were people (e.g. Barton, 2005; Barker et al., 2007; Kourampas et al., 2008; Roberts and Petraglia, 2015; Summerhayes et al., 2016). In Australia, the development of rainforest adaptations can only have emerged during the Holocene primarily because these environments were not established in large enough tracts to be viable prior to this time (but after human colonization). The unique archaeological record documented in the Australian tropics offers a particularly interesting case study: not only because are there long term regional environmental sequences documenting shifts in vegetation composition through the Pleistocene and Holocene, but the lack of

2 agricultural societies in Australia provides an opportunity to track Holocene tropical rainforest use uncomplicated by the possibility of agricultural food exchanges.

Here we present the results of an exploratory study to determine whether phytolith and ancient starch were preserved in late Holocene open-site archaeological deposits from the North Queensland Wet Tropics, Australia (Fig. 1), and if so, how they may inform us about human exploitation of tropical rainforests. In particular, we are interested in the development of subsistence strategies and forest management/niche maintenance during the late Holocene in two sites, Goddard Creek and the Urumbal Pocket in the Wet Tropics World Heritage Area (WHA). Initially conceived as a pilot project to evaluate the preservation of micro-botanical remains in Queensland tropical soils, the surprisingly good preservation makes it possible to sketch human-environmental impact and plant use at both sites.

2. Background

2.1. Niche construction and rainforest occupation in Northern Queensland One of the strategies implemented by people in adapting to the expansion of tropical rainforests during the early to mid-Holocene was forest and gap management, or niche construction (Laland and Brown, 2006; Laland et al., 2007; Laland and O’Brien, 2010). There is growing evidence (outside Australia) that as tropical forests expanded, people maintained gaps in the forest through burning and other strategies, to support and maintain concentrations of economic plants and animals (Kealhofer, 2003; Terrell et al., 2003; Hunt and Premathilake, 2012).

Niche construction theory (NCT) provides a useful interpretive framework within which to consider the outcomes of human-environment interactions in the Australian context (e.g. Laland and O’Brien, 2010). As an heuristic tool, NCT aids in identifying the driving factors in rainforest settlement and charting the evolution of rainforest culture in Australia. The Australian case has a number of parallels with the arguments concerning the emergence of agriculture in other societies (see Smith, 2016). While many of the apparent features of pre-agricultural societies are shared with that of rainforest Aborigines in northeastern Queensland, the trajectories are clearly very different. Notably, plant and animal domestication, as described for eastern North America or South America (Smith, 2016), never eventuated in Australia.

As Smith (2016: 312) states “NCT recognizes the capacity of organisms to shape their own evolutionary trajectories through engineered enhancement of their surrounding environment. Adaptation is not always in response to disequilibrium in local environments. Niche construction involves an organism altering the relationship between itself and its ecosystem, and such modification can provide individuals and populations with an evolutionary advantage.”

2.2. Environmental and archaeological context The history of tropical rainforest settlement in far northeastern Australia appears to differ markedly from the Pleistocene records observed further north from northernmost Sahul. To better understand the relatively late settlement of rainforest environments in Australia, we need to consider the impacts of the last Glacial cycle in terms of reconfiguration of these eco-zones. The Last Glacial cycle was characterized by climatic variability coupled with a trend to increasing aridification that began hundreds of thousands of years ago (see Nanson et al., 1992; Wroe et al., 2013). As different vegetation communities reconfigured in response to these profound changes in water balance and temperature, rainforest zones contracted to be replaced by sclerophyllous vegetation (Moss and Kershaw, 2007; Reeves et al., 2013). Notably, in their study of charcoal evidence from rainforest from this region, Hopkins et al. (1993: 370) speculate that for NE Queensland ‘‘the distribution of rainforest in the late Pleistocene was a highly fragmented version of that which exists today with rainforest persisting in fire-proof topographic and edaphic location(s)”. If people did exploit these rainforests fragments, it likely occurred in a mosaic environment, with high resource diversity. With the onset of more stable climatic conditions, in the early Holocene, rainforest tracts and boundaries stabilized by approximately 8000 BP (Moss et al., 2012), when the earliest signal of people in these newly established rainforest tracts appears.

3 Current knowledge about tropical forest occupation has been greatly expanded in the last two decades following systematic survey and excavation in the Wet Tropics World Heritage Area, southwest of Cairns, in northeastern Australia (see Stevens, 2004; Cosgrove et al., 2007; Ferrier, 2015; Fig. 1). The results of this work have greatly improved our understanding of the sequence and timing of human colonization of these environments (see Cosgrove et al., 2007; Ferrier and Cosgrove, 2012). This more recent work builds on earlier investigations at Jiyer Cave on the Russell River and the Mulgrave River 2 site by Horsfall (1987, 1996) and Cosgrove and Raymont (2002). Furthermore, Murubun Shelter, located in what is currently wet sclerophyll forest (on the rainforest margins), has confirmed a Pleistocene (pre-LGM) human presence in this region from at least 30,000 years ago (Cosgrove et al., 2007).

The archaeological sequences mentioned above show broad inter-site similarities in content and age, and have been interpreted as indicating that the mode of rainforest settlement in northern Australia was initially ‘low level’ in the early Holocene and building to ‘occasional use’ by the mid-Holocene (Ferrier and Cosgrove, 2012). While the mid- Holocene is marked by an increase in the number of people in the landscape, it isn’t until the late Holocene that permanent settlement or ‘intensive use’ is identified (see Horsfall, 1987, 1996; Cosgrove and Raymont, 2002; Cosgrove, 2005; Cosgrove et al., 2007; Ferrier and Cosgrove, 2012; Ferrier, 2015). The permanent rainforest settlement that emerged in the Late Holocene did so against a backdrop of climatic variability at c. 2500–1700 cal BP, correlated to drier conditions associated with ENSO activity, which commenced after 5000 BP (as observed in regional pollen sequences from Witherspoon Swamp and Lake Euramoo (Turney and Hobbs, 2006; Kershaw, 1994; Haberle, 2005; Moss et al., 2012)).

Settlement patterns are inferred from significant increases in artifact discard and (carbonized) nutshell concentrations. Unfortunately, the acidic soils that characterize the rainforest sequences have precluded the preservation of faunal remains, so faunal exploitation in the rainforest remains unknown. The most (archaeologically) durable of the materials is stone. Of particular interest are the morah stones (incised grinding stones manufactured from slate) required to process starchy nuts (Field et al., 2009). In some places ‘shell graters’ were also used for this purpose. As access to running water was important in the leaching process, it is likely to have dictated where wet season camps were established (Pedley, 1992).

In addition the material culture that survives in archaeological sites (ground and flaked stone), other less durable items have been well documented from the rainforest in the ethnographic literature (see Khan, 1993, 1996, 2004). It is widely recognized that the North Queensland rainforest peoples have some of the richest material culture known from the Australian continent. The material objects include T-shaped stones called Ooyurkas (Fig. 16; Cosgrove, 1984), Morah stones (Field et al., 2009), woven baskets (dilly bags), wooden swords and highly decorated shields manufactured from rainforest tree buttresses – and all unique to this corner of Australia (see Khan, 2004; Ferrier, 2015). Ferrier and Cosgrove (2012: 106; see references therein) recount the use of lawyer cane for making baskets for storing and leaching of toxic starchy nuts. It is well known that organic remains are rarely preserved in tropical rainforest contexts, and the Wet Tropics of NE Queensland are no exception. Wood and bone have not been recovered from the open sites, though stone, charcoal and carbonized nutshell remains are abundant.

2.3. Niche construction and ethnohistoric observations in Far North Queensland The plant microfossil record examined in this study constitutes a novel approach to investigating indigenous use of forest resources in tropical rainforests. In conjunction with these studies we have engaged a range of ethnohistorical sources to provide further insights into forest occupation. Numerous early explorers and anthropologists recorded observations of traditional lifeways of rainforest peoples and these records provide a window on settlement patterns (location of settlements, shelter construction, forest path maintenance), resource use (toxic starchy nuts, palms and fauna), forest transformations and management (burning sclerophyll forest patches) and technological innovations (Morah stones, ground edge axes) (see discussion in Ferrier, 2015).

4 Many of the activities observed at first contact with Europeans are clear examples of niche construction within the rainforest environment, but the question remains as to the antiquity of these activities and the sequence of emergence of technologies such as complex processing of toxic starchy nuts. Two key factors in Niche Construction theory – environment (maintenance and management) and resource use (e.g. shelter construction and food resources) – can be explored by examination of the ethnohistoric and plant microfossil record.

2.3.1. Environmental management

The evidence from Murubun Shelter places people in the region from at least 30 ka, yet the evidence for a human presence at Murubun comprises only a few artifacts after which time the site was abandoned until after the LGM, with another short period of visitation around 16 ka (Cosgrove et al., 2007). It is not until the Holocene that the artifact discard rate starts to rise, a trend also reflected in the rainforest sites, presumably as populations increased or site visitation rates became more frequent. These developments occurred against a backdrop of stabilizing climate (climatic optimum beginning around 8 ka) and rainforest expansion.

What is challenging to determine, is how people managed their resources and the landscape as the sclerophyll forest contracted and rainforest cover gradually increased. Expansion of rainforest must have resulted in a dynamic period of adjustment and adaptation with the shift to closed forest and a reconfigured resource base. The transition from sclerophyll vegetation to rainforest would have occurred over many human generations, and people are likely to have maintained a presence in this space, regardless of the dominant forest types. Rainforest expansion developed under higher precipitation regimes and higher temperatures compared to the Late Pleistocene and we propose that the archaeological sequences within these forests only began accumulating as people started interacting with, and repeatedly returning to these specific locations. The persistence of the Eucalyptus pockets (cf. Urumbal Pocket) within the rainforest, plus the associated archaeological sites, in close proximity to the Tully River stream channel, present a clear example of niche construction that has been managed and maintained over generations, if not millennia.

Ethnohistorical data show that rainforest peoples were effectively sedentary during the wet season, living in small settlements, connected by maintained access tracks through the rainforest (Goddard Creek and Urumbal Pocket were located on one of the maintained tracks connecting the lowlands with the tablelands (see Ferrier, 2015 and references therein)). These patches were burnt at the end of the wet season, and this is reflected in the modern day vegetation, which is composed of fire resistant species such as Eucalyptus, Banksia, Casuarina and Xanthorrhoea species. Maintenance of the clearing by burning would preclude fire sensitive rainforest species and encourage the regeneration of these wet sclerophyll taxa (see Hopkins et al., 1993), maintaining an open canopy and increasing biodiversity within this location, as also reported for other environments (e.g. D. Bird et al., 2005; M.I. Bird et al., 2005; Bliege Bird et al., 2008).

2.3.2. Resource use Resource use, in the context of this study, relates to plant use for hut or shelter construction and food. Both activities are critical facets of niche construction. Some techniques of food exploitation are unique to rainforest societies, making use of a range of starchy plant species that require complex processing to remove toxins or bitter compounds (Table 1).

2.3.2.1. Shelters. As noted above, Aboriginal groups lived in sedentary ‘villages’ in the rainforest during the wet season. An important feature of these settlements, as recorded by Roth (1910) was the construction of shelters in cleared areas of rainforest. He describes the shelters as being thatched with grasses, Imperata arundinacea (Blady grass), and the frames made from palms, specifically Calamus sp. (Wait-a-While) and Licuala muelleri (synonym of Licuala ramsayi, Fan Palm). Other economic plant species recorded include Cycas sp. (Cycad) (Memmott, 2007). Historical accounts also relate the use of lawyer cane (Calamus spp.) to make huts (Memmott, 2007, see also Ferrier, 2015: 26–36).

5 Ropes and nets were also made from Calamus spp. Most of these species (cycads excepted) are phytolith producers and as such often persist in the plant microfossil record.

2.3.2.2. Economic plants. Starchy plants have been noted as a component of rainforest diets, and they appear to have been a mainstay. The primary source of starch are tree nuts that contain toxic compounds, which can be fatal if consumed without processing to remove these compounds (e.g. McKenzie et al., 1988). People actively maintained areas to increase productivity of these important species; in some places, noted concentrations of economic nut trees have been observed (Cosgrove, 1996). The nuts are produced in large numbers during the tree’s respective fruiting seasons and can easily be collected from the forest floor. Cycads (Cycas media) were also important and while not a feature of the rainforest are commonly found growing in the drier country on the rainforest margins. In the case of Cycads from the Cape York Peninsula, Harris (1977) has argued that the concentrated stands of these plants that he observed were likely to be a direct result of active management by Aboriginal people. In addition to starchy tree nuts, yams (subterranean tubers) were also eaten, and at least one of these – Dioscorea bulbifera – contained bitter compounds that had to be removed by leaching.

The antiquity and history of the complex processing required to render the toxic tree nuts edible is still not clear, although toxic starchy kernels produced by Cycads appear to have been exploited for millennia (Asmussen, 2011; Tuechler et al., 2014). Ethnographic research by Pedley (1993) documented the complex processing undertaken by rainforest dwelling peoples. The process can take days and involves baking the nuts in a ground oven, followed by pounding to break up the starchy flesh and then leaching in running water, often for several days (see Pedley, 1993). Notably when Europeans arrived with processed wheat flour, these starchy tree nuts were one of the first bush foods to be dropped from the diet – presumably because of the amount of work required to extract the starch. Interestingly, the Glycaemic Index for Castanospermum australe (Black Bean) is very good at 11 (very low), compared to that of wheat flour bread, which is 100 (Brand Miller et al., 1993).

Pedley’s work was subsequently expanded on by Tuechler et al. (2014), who investigated the various stages in the processing methods and how the nutritional value changes at the each stage in the process. After processing, the availability of carbohydrate (total starch) increased (as for other toxic starchy nuts). Processing has a dramatic effect on the Black Bean in terms of total available starch, but also significantly decreases the total sugars and perhaps the palatability as well, and as such, may not have been a preferred food choice. Various accounts indicate that both Black Pine and Black Bean were not necessarily preferred over Black Walnut and Yellow Walnut (see discussion in Harris, 1987 and Tuechler et al., 2014). Black Pine appears to have a more restricted distribution, while Black Bean is at the upper limit of its range on the Atherton Tablelands. Furthermore, Pedley (1993) noted that Black Bean was collected during the winter months, and in the study presented here, its presence or absence in the archaeological record may be an indication of seasonality of site occupation.

Carbonized nutshells from economic tree species are ubiquitous in the North Queensland rainforest archaeological sequences and are thought to be one of the keys to understanding permanent rainforest occupation (see Cosgrove, 1996, 2005). Evidence for toxic starchy nuts has primarily been in the form of carbonized endocarps, the hard outer shell of the nut. However only a small percentage of these nutshell fragments (c.10%) contained enough diagnostic features to be identified. Two economic species were found: Beilschmiedia bancroftii (yellow walnut) and Endiandra palmerstonii (black walnut). It was not possible to ascertain whether these were the only nutshell fragments preserved due to the low identification rate. Pouteria sp. was also identified, though whether it was an economic/food plant is unknown (Cosgrove et al., 2007).

3. The research problem High population densities that typify the various linguistic groups in NE Queensland require a reliable and abundant food supply. Practices such as complex processing of toxic starchy nuts, construction of shelters and maintenance of open patches within the rainforest beg the question of time depth: when did these behaviors and material culture

6 develop and can any of these be detected in the fossil record in an environment where preservation of organic remains is generally the exception rather than the rule? The finds recovered from the sites studies here, Goddard Creek and Urumbal Pocket, were predominantly flaked and ground stone artifacts, carbonized nutshells and charcoal. Bone and other organic macro-remains were not preserved. However, the highly organic sediments associated with these open sites have the potential to preserve phytoliths, and other plant microfossils including ancient starch. Recent developments in the methods for the identification of starch grains to plant taxa has meant that we now have more confidence in ascribing identifications to unknown starch grains (Coster and Field, 2015), and therefore to species being exploited. The study presented here is the first application of this method to an archaeological problem.

4. Site setting The sites investigated in this study are found in the Wet Tropics World Heritage Area on the Atherton Tablelands, southwest of Cairns in Far North Queensland, Australia (Fig. 1). Urumbal Pocket is a wet sclerophyll patch at an elevation of approximately 750 m ASL, dominated by Eucalyptus spp., Xanthorrea spp., Casuarina cunninghamiana, Banksia integrifolia and other fire tolerant species (Cosgrove et al., 2007). The pocket is so named because it is a remnant patch of wet sclerophyll forest, completely enclosed by rainforest. Today, the Urumbal Pocket is located on the shores of Koombooloomba Dam, a hydroelectric dam constructed in the 1950s. The Urumbal Pocket site (Figs. 2 and 3) is located just below the high water mark on a spur on the lake edge and adjacent to the flooded Tully River channel.

The second locality is on Goddard Creek, a tributary of the Tully River, at a slightly lower elevation and the site is often completely inundated when Urumbal Pocket is dry. Goddard Creek is located approximately 3 km from Urumbal Pocket (Fig. 4) and is situated on a spit of land immediately adjacent to the Goddard Creek channel Prior to the dam construction the site would have been located within the rainforest proper.

5. Materials and methods

5.1. Excavation Urumbal Pocket was excavated between 2002 and 2004 as part of an Australian Research Council Discovery Project awarded to Cosgrove and Field (DP0210363). Six 1 m x 1 m pits were excavated to bedrock (see Cosgrove et al., 2007; Ferrier and Cosgrove, 2012 for details) and two stratigraphic units were identified (Fig. 3, Table 2):

• Stratigraphic Unit 1 – a dark undifferentiated humic layer; and • Stratigraphic Unit 2 – a relatively shallow lighter layer overlying decomposing granite bedrock.

Archaeological finds recovered during excavation consisted primarily of flaked quartz with minor raw materials including rhyolite, quartzite and silcrete, some slate/granite ground stone, carbonized nutshells and charcoal (Cosgrove et al., 2007). Radiocarbon analyses determined that the initial visitation by people to Urumbal Pocket occurred during the early Holocene between 8000 and 7000 cal BP (Cosgrove et al., 2007: 156). Stone artifact discard rates peak at around 2100 cal BP, and this was followed by nutshell discard rates peaking at around 1200 cal BP (Cosgrove et al., 2007: 156). Beilschmeidia bancroftii was the most commonly identified species in the nutshell assemblages.

Goddard Creek excavations were undertaken over two field seasons and two 1 m x 1 m pits were excavated to bedrock (Cosgrove et al., 2007). The pattern of archaeological finds and chronology effectively mirrors the trends observed at Urumbal Pocket, although here the earliest archaeology levels dated to c. 5100 cal BP (see Cosgrove et al., 2007).

7 5.2. Samples and sampling

5.2.1. Sediment samples Soil samples were collected at 5 cm intervals from section profiles after the completion of archaeological excavations at Goddard Creek and Urumbal Pocket. Samples were collected from squares Z3, O2 and S2 at Urumbal Pocket and from Square A2 at Goddard Creek. Samples were processed to extract phytoliths and starch.

The samples were sieved using a 53 µm and 125 µm Endecott sieve followed by a heavy liquid separation with Sodium polytungstate (Specific Gravity 2.35). The phytolith and starch preparations were mounted in either Karo® syrup (starch) or Permount (phytoliths) (see Fullagar et al., 2008). For phytoliths, slides were scanned at 400× magnification until 200 phytoliths were recorded. Total slide scans were undertaken for the ancient starch study. The latter strategy was pursued because the concentration of starch was very low in these samples and we needed to maximize the counts so they could be calculated as concentrations per gram. Slides were examined using a Zeiss Axioskop II with Nomarksi optics. Images were collected using a Zeiss HRc digital camera and archived with Zeiss Axiovision software. Starch grains were digitized and analysed using Matlab® (MATLAB and Statistics Toolbox Release 2015ba, The MathWorks, Inc., Natick, Massachusetts, United States) and identifications were based on the comparative reference collection compiled by the authors for the Wet Tropics (Coster and Field, 2015). Phytolith identification was based on a large phytolith reference collection for Southeast Asia (Kealhofer and Piperno, 1998), augmented by additional habitat specific phytolith producing taxa from North Queensland. Phytolith diagrams were prepared using Tiliagraph® (Grimm, 2004).

5.2.2. Grindstone samples Three grindstones were included in the starch analyses (Fig. 5): UP A2 SPIT 3 – recovered from excavations at Urumbal Pocket; KD02-2002a – a surface find recovered from Sylvania Creek, within 500 m of Urumbal Pocket, and Murubun Shelter – a surface find from inside the shelter. Murubun Shelter is located in the rainforest margins within wet sclerophyll forest, adjacent to, and above, Blunder Creek (Fig. 1; Cosgrove et al., 2007). The grindstones were sampled by pipette with sterile distilled water. Water was applied directly to the stone surface, particularly focusing on the incised channels in the rock surface. A nylon pipette tip was used to scrape along the inside of the channel in order to dislodge any material in the v-shaped cavities. The samples were then removed to a 1.5 ml micro-centrifuge tube and further processed in the laboratory. The samples were generally very small and no further processing was undertaken in order to minimize sample loss. In cases where the sample volume was larger, they were centrifuged to reduce the volume and then mounted in Karo on glass microscope slides for examination, as for the starch sediment samples.

5.2.3. Geometric morphometric analysis In this study we have applied and expanded the methods of Coster and Field (2015) to an unknown set of starch grains recovered from Urumbal Pocket, Goddard Creek and the three slate incised ground stone artifacts described above.

The geometric morphometric features of these grains of unknown plant taxa were used, in combination with an appropriately curated modern reference collection (Figs. 6 and 7), to infer the probable species of origin (see Coster and Field, 2015). The geometric morphometric measures, or predictor variables, calculated for the grains were the hilum position, perimeter, area, maximum length through the hilum, and the Fourier signature of the grain outline – a decomposition of the shape into its principle components (see Coster and Field, 2015).

The modern comparative reference set of species included, and the number of individual grains examined, is presented in Table 3. The optimal classifier for the rainforest reference set was a quadratic classifier. The predictor variables used to best discriminate between species were area, perimeter and Fourier signature (components 0–4) (see Coster and Field, 2015 for the full sets of classifiers and predictor variables considered). A dendrogram demonstrating the separation (MANOVA of the predictor variables measuring the Mahalanobis distance between the group means) between the species is shown in Fig. 8. It is clear that most species are well separated on the 8 dendrogram indicating that is it feasible to use these predictor variables to discriminate between the different species. The confusion matrix is presented in Fig. 9. The optimal classifier also divided the reference species measurements into subsets, which accounted for intra-species variability and orientation (within the slide mounting media), and recombined the output using a vote algorithm for the final prediction (see Coster and Field, 2015).

The classifier performance was assessed for true/false positive and negative rates upon re-substitution of the original training set, and also by 50-fold cross-validation where performance on the withheld subset (Coster and Field, 2015). A reverse cross-fold validation error (CVE) was determined measuring the predictions that were not actually from that grain species. The results for the predictions were then assessed according to these two confidence measures. The cross-fold confidence is presented for those grains identified to be at the site at the top (Fig. 10). Note that classifications with cross-fold validation errors greater than 0.3 are considered to be unreliable. The lower plot shows the predictions for the unknown grains. The 0.3 CVE threshold is indicated by a red dashed line. Those to the left of the line have CVE within the more reliable prediction range.

The method outlined in Coster and Field (2015) was further refined by assessing the prediction scores output by the classifier as a function of the reference set species. The re-substitution errors from the reference grains was used to assess the distributions of true and false positives for the training set and the proportion of true positives for that species, (referred to as PPV) was calculated. Cutoffs for this were set at 70%, 80% and 90% and the corresponding prediction scores determined. If the prediction score corresponded to PPV > 0:9, the entry is a confident prediction (i.e. not any of the other species in the reference set). If the prediction score corresponds to 0:8 < PPV ≤ 0:9 then the prediction is probable. If the prediction score corresponds to 0:7 < PPV ≤ 0:8, then the prediction is likely. Classifications with scores corresponding to PPV ≤ 0:7, although possibly present, were not considered.

The unknown grains were then manually (visually) assessed by an expert starch analyst (JF). The unknown grain was compared with those grains in the reference set that were the closest match across the predictor variables. The manual assessment took categorical and subjective attributes of the grains such as position of the hilum, presence or absence of lamellae and other surface features into account as well as the cross-fold validation confidence and PPV for the predicted species. Each prediction was assessed as validated, probable or a false positive. The results for the validated classifications are shown in the species colors, and the probable classifications in gray (Figs. 11 and 12). It is important to note that this analysis focused on creating a highly confident measure of the presence of a particular species (true positive), rather than the assessment of abundance across different species.

6. Results

6.1. Ancient starch Starch was recovered from all squares (Z3, O2, S2) in the Urumbal Pocket sediments (Figs. 11 and 12). Starch was only observed in one sample from Goddard Creek. The Goddard Creek site is inundated for most of the year, which likely affected starch preservation. The highest concentrations of starch were observed in the uppermost levels of the Urumbal Pocket Squares O2 and S2 and from 15 cm depth in Square Z3 (Fig. 13). Starch concentrations decreased towards the base. A range of economic tree species were identified, with Lasjia whelani (Whelan’s macadamia) and Endiandra palmerstonii (Black Walnut) present throughout the sequence. Other species present included Endiandra insignis (Hairy Walnut), Beilschmiedia bancroftii (Yellow Walnut) and Dioscorea transversa (Native Yam). Lasjia whelani (Whelan’s macadamia) and Endiandra palmerstonii (Black Walnut) were also identified in the Goddard Creek sequence, confirming their use at both sites.

The sediment sampling was undertaken at 5 cm intervals in each sequence to establish whether starch survived in cultural sediments from open sites, and if so, whether there was attrition of starch through time and, finally, whether we could identify these grains in order to explore the possible implications of their survival in a cultural sequence. The starch was generally well preserved and considerable variation in morphology and sizes was observed across the samples.

9 Two surface-find grinding stones and one excavated grinding stone fragment yielded starch grains. All three grinding stones sampled were manufactured from slate and had grooves in their used surfaces, which likely acted as residue traps. The three grinding stones are consistent with Morahs described elsewhere (see Field et al., 2009). The number of starch grains digitized for this study were: Urumbal Pocket excavated fragment (UP A2 Spit 3): n = 7; Sylvania Creek surface find (KDO2-2002a): n = 29; and the Murubun Shelter grindstone: n = 64. The total number of starch grains digitized is less than the number recovered because some grains were damaged and others were partly obscured by debris on the slide.

The comparative reference set used for this study is shown in Table 1, and represents the primary economic species from this area that are likely to contribute to the starch assemblages. While we have tried to include as many species as possible, we may have missed some unknown non-economic, or economic starch plant taxa. Examples of the starch grains and their morphology are presented in Figs. 6 and 7.

Not all starch grains could be attributed to specific plant taxa. Nonetheless, many starch grains were attributed to a species of origin, and the percentage of species identified to plant taxa was relatively consistent across all samples (17–36% confidently identified). Interestingly, in the sediment samples a number of species not identified in the macrobotanical study were found: Lasjia whelani, Endiandra insignis and Dioscorea transversa. In Square O2, 15 cm depth, three other species were also identified: Cycas media, Tacca leontopetaloides and Prunus turneriana (Fig. 11). These three species do not turn up anywhere else in the sequence, but are present on the Murubun Shelter grindstone (Fig. 12). Beilschmiedia bancroftii is only positively identified in the top sample of Square Z3 and Castanospermum australe was not identified in any sediment sample.

6.2. Phytoliths The Goddard Creek and Urumbal Pocket cultural deposits both yielded abundant phytoliths. A Principal Components Analysis (PCA) of summary types for Urumbal Pocket [Z3] and Goddard Creek showed that Urumbal Pocket is very different from Goddard Creek and that there are strong internal differences within the Urumbal Pocket sequence. In overall terms, the two sequences are distinctly different from each other (Figs. 14 and 15), which is not unexpected considering their different site contexts. Over the course of these sequences, the Goddard Creek (GC) site appears to have been continually covered by rainforest, while Urumbal Pocket (UP) persisted, or was maintained, as a small remnant of wet sclerophyll forest surrounded by rainforest.

The differences observed between the UP and GC sequences reflect the dominant vegetation types at each location (Table 4). Both panicoid grasses and palms are much more common at Urumbal Pocket [Z3] (2–3×), while bambusoid types are rare at both, particularly at GC. Based on sizes and shapes (ovoid), it is likely that the range of palm species is also different at each site (ovoid types are consistent with Calamus sp. [cf. lawyer cane]).

The pattern of phytolith types and the presence of burnt phytoliths suggest that there is considerably more burning at Urumbal pocket, with an apparent cyclical pattern of disturbance (as signified by the SRS types [small rough spheres]; Table 4; Fig. 14). The GC sequence is more linear, with the top two samples more similar than bottom two samples in overall abundance of LRS [large rough spheres]/SRS forms (Fig. 15). Another contrast between the sites is that the GC sequence has a particular form – fine spiculate spheres – that is not present in the at Urumbal Pocket record. Furthermore, MFPs (multifaceted polyhedrals) and sclereids are more common at Urumbal Pocket. The presence of these types may be indicative of a greater diversity of dicotyledonous species/trees at UP. Certainly, MFPs are found in a limited number of dicotyledonous taxa (e.g. Annonaceae, see Kealhofer and Piperno, 1998: Figs. 29 and 39).

There are also a number of similarities between the two site locations – both have very few grasses with the vegetation profile consisting mostly of trees and shrubs. In addition, both have a smattering of globular or spherical irregular lumpy forms – some diagnostic, some not. The extremely low representation of grasses at GC suggests this was not an open/terrestrial habitat – or even woodland.

10 In general terms, all the phytolith types in Table 4 that are to the left of the palms are Dicotyledonous species, and in most cases are arboreal to shrubby. SRS forms are often associated with Euphorbiaceae regrowth species in other regions, though it is not clear if the same correlations are reflected here. These particular forms, while present, are quite different at these sites. SRS appear to be inversely correlated with the burned palms.

A Principal Components Analysis of summary types (not shown) highlights the differences between Urumbal Pocket and Goddard Creek – as well as showing that internal differences within Urumbal Pocket (Square Z3) are quite strong as well (e.g. samples 1 and 2 stood out as almost outliers, while 3 and 5, and 4 and 7 were quite similar) Fig. 17. The data sets for each site are quite small – but show clear environmental differences, and a suggestive pattern of use/s at Urumbal Pocket over time.

7. Discussion In their review of the prehistory of tropical rainforests, Roberts and Petraglia (2015) called for more detailed documentation from different regions and contexts, to better understand how humans exploited these unique environments in different parts of the globe. In Australia, there are a number of different rainforest types found across the continent and the history of their distribution varies widely. They are very diverse floristically and the range of economic plants within these environments also varies considerably, especially between dry and wet rainforest types (see Beck and Balme, 2003). In this study we have focused on the tropical rainforests of NE Queensland where a rich archaeological record has been recovered in a location with robust palaeoenvironmental and ethnohistorical data.

Many of the observations by early explorers in northeastern Queensland speak of Aboriginal groups actively modifying, maintaining, and in some cases manipulating their environments and living spaces. Combined with a rich material culture, the activities of people within these environments were critical to the management of their resources, the creation of territorial boundaries, and importantly must have been developed and passed down over many generations. The plant microfossil record has enabled us to explore the antiquity of some of these practices, in this case settlement history and plant resource use.

7.1. Niche construction in the rainforest Global climatic change drove significant environmental reconfiguration at the close of the Pleistocene, and people maintained a presence in these landscapes – a dynamic interaction manifested as maintenance and management of different, possibly strategic, points in the landscape. Perhaps these were not too different from the sweet spots proposed by O’Connell and Allen (2012). We suggest, however, that these sweets spots were managed and enhanced so they could be revisited, re-used and exploited by subsequent generations. Here we discuss the evidence for such enhancement during the late Holocene.

7.1.1. Settlement – paths and water and location The microfossil record identified in the Goddard Creek and Urumbal Pocket sequences mirror their modern local vegetation profiles. Goddard Creek is a campsite located within the rainforest proper, while Urumbal Pocket is a wet sclerophyll forest pocket enclosed by rainforest. As both sites are in relatively close proximity to one another, it is not surprising that the finds recovered during excavation show similarities, as do the respective ages of the sequences therein (Cosgrove et al., 2007). Both sites are located adjacent to river/creek channels and in all likelihood these locations were situated to facilitate the processing of toxic plant foods. The phytolith sequence shows that both locations have supported similar communities during the period of intensive human activities. In the case of Goddard Creek, the use of fire appears to increase over time, with people perhaps more aggressively maintaining and managing an opening in the rainforest. Recent studies of wood charcoal from Goddard Creek confirm the use of rainforest species in the macro charcoal record (King, 2015). In the case of Urumbal Pocket, the persistence of a wet sclerophyll pocket within the rainforest is necessarily the result of a long term burning regime (see Hopkins et al., 1993) and one that would have maintained and supported biodiversity of both plants and animals. As such, fire appears to be an important management tool at Urumbal Pocket and Goddard Creek in the late Holocene. The

11 presence of SRS (small rough spheres), which are typical of Euphorbiaceae, are indicators of disturbance and/or regrowth, being the first species that emerge after clearing/burning. The contrast in phytolith assemblages between the two sites attests to the continuity of use and management regime that must have endured for at least the last 2 millennia, until European arrival. Rainforest peoples have been actively manipulating this space to ensure access and availability during the wet season, conforming to the predictions of the NCT model.

7.1.2. Resource use – shelter construction and plant processing The abundance of palm phytoliths in the Koombooloomba Dam [GC and UP] sequences may also reflect cultural practices at both sites. The incidence of burnt palm phytoliths is also notable and may be evidence for the construction of shelters and their subsequent burning when sites were abandoned at the end of the wet season. Shelters or ‘gunyahs’ constructed from lawyer cane (Calamus spp.) were commonly observed in rainforest communities (see Roth, 1910) and the presence of the burnt, and unburnt, palm phytoliths in the Urumbal Pocket sequence may signal these activities. Processing of toxic starchy nuts at rainforest archaeological sites is inferred by the presence of carbonized nutshells of rainforest economic species. Varying concentrations of nutshells from economic toxic tree nuts have also been reported from Jiyer Cave and Mulgrave River 2 (Horsfall, 1987), in addition to Urumbal Pocket and Goddard Creek (Cosgrove et al., 2007). While Endiandra palmerstonii and Beilschmiedia bancroftii appeared to be the two primary economic starchy species exploited (Cosgrove et al., 2007; Ferrier and Cosgrove, 2012), other species were predicted to be also present including, for example, Sundacarpus amarus and Castanospermum australe, which have been observed growing in the area.

The sediment starch record has served to provide more direct evidence of other starchy economic plans at the two rainforest sites examined here. Starch grains from Lasjia whelani (Whelan’s Macadamia), Disocorea transversa (Long Yam) and Endiandra insignis (Hairy Walnut) are present across the various excavated squares. Beilschmiedia bancroftii was identified in the upper layers of one square. Interestingly, in one horizon, in one square, we also identified three species normally associated with the rainforest/ sclerophyll forest interface: Tacca leontopetaloides (Polynesian Arrowroot), Prunus turneriana (Wild Almond) and Cycas media (Cycad). None of these species were identified growing in the Eucalyptus pocket or its vicinity during the field season. We conclude that they were either brought in, or are no longer present in the study area. All of the plant taxa identified here are economic starchy plants that require complex processing to render them edible (Pedley, 1993).

At Urumbal Pocket, there is a distinct contrast in starch recovery between O2/S2 (up slope and away from the river channel) and Z3 (on the flattest part of the slope and closest to the river channel). The interpretation is tempered by the fact that temporal resolution in these samples is very low and only broad conclusions can be drawn from these data. Nonetheless, the differences in concentrations may reflect some spatial patterning in the use of the site. Squares O2/S2 have greater preservation in the upper 2 samples, whereas Z3 has much higher starch concentrations in the third sample. Squares O2 and S2 were upslope from Z3, which is closer to the shoreline of the lake. The variations in concentration may also reflect some spatial variation, perhaps as processing areas were concentrated in different parts of the site at different times in the past.

A very small fragment of a Morah (slate incised grindstone) was recovered during excavation from Urumbal Pocket (Fig. 5A), from an horizon dated to 514 ± 51 BP (Cosgrove et al., 2007: 156). The fragment was found within approximately 10 cm of the high starch counts for Z3, (Spit 7, dated to 672 ± 39 BP, Cosgrove et al., 2007: 156). Eight starch grains were isolated, of which seven were digitized for this study. Identification to specific plant taxa was not possible when the starch was first examined, though maximum length measurements appeared to be consistent with Beilschmiedia bancroftii, providing support for the identifications from nutshell data. Notably, the length measurements of the starch grains of B. bancroftii overlap with other species (Cosgrove et al., 2007; Field et al., 2009). The geometric morphometric approach (Coster and Field, 2015) identified three of the eight grains as Endiandra insignis, Lepidozamia hopei and a possible E. palmerstonii. The rainforest starch taxa show considerable variability, but some also exhibit similarities; unless a clear diagnostic form is found, as in some Dioscorea bulbifera grains, these starch producing species are very difficult to separate on the basis of expert visual examination alone.

12 As we used a very conservative approach to acceptance or rejection of identification to plant taxa using the geometric morphometric method, it may be possible, with further refinement of the method, to identify more of the starch grains in the future.

Two grindstone fragments from surface contexts – one from within the rainforest and another from Murubun Shelter in the adjacent wet sclerophyll forest – provided further detail on economic starchy plants exploited. E. palmerstonii and Lasjia whelani were identified on the Sylvania Creek surface find (KD02-2002a) and this is consistent with the overall identifications made at Urumbal Pocket, less than a kilometer away. A larger range of species was identified on the Murubun Shelter grindstone. It may reflect a more wide ranging collection strategy, or more regular visitation to the shelter, with the rainforest resources targeted from the adjacent open forests. It is possible that rockshelters on the stable rainforest boundaries (see Moss et al., 2012) may play an important role in provisioning Aboriginal groups in the dry country where resources were less reliable. It may be that, as opposed to the proposition that the rainforest resources required supplementation from adjacent habitats, people moving through drier areas were supplementing their food supply in the rainforest.

Perhaps the most surprising absence from the starch assemblages is that of Black Bean (Castanospermum australe). Notably, it is less easy to separate analytically from other species (Fig. 10). Furthermore, we cannot rule out the possibility that the very conservative approach used in this study may have inadvertently excluded some grains that belong to this species. However, it is more likely that Black Bean starch grains were not there to begin with. Considering the numbers of grains analyzed overall (1021) and the fact we have identified Black Bean on Queensland Museum grindstone specimens (unpublished results), indicates to us that Black Bean is not present in the Urumbal Pocket assemblage. The question concerning Black Bean is, even if available, whether it would have been collected in preference to other more palatable species?

The evidence presented here, in combination with the ethnographic observations has important implications for Niche Construction Theory [NCT]. While NCT has been proposed as an important facet of evolutionary theory, it has been difficult to explore through the archaeological and microfossil record (see Smith, 2013). We would argue that the unique rainforest adaptations known for the North Queensland Wet Tropics, the active maintenance of the wet sclerophyll pockets within the rainforest (as seen at Urumbal Pocket and the gradual transformation over time documented for the Goddard Creek site), are clear evidence that niche construction has been a significant and ongoing set of activities that have shaped both the subsistence and settlement patterns of rainforest Aboriginal peoples, as well as the local environment. Niche construction in tropical rainforests is also likely to be instrumental in increasing plant and fauna biodiversity and creating unique ecosystems, such as those seen in the Eucalyptus pockets within the rainforest proper. The early Holocene expansion of rainforests, the exploitation of toxic starchy nuts and the maintenance of the wet sclerophyll pockets may have all combined to influence the trajectory of rainforest cultures and their unique material culture, including incised grinding stones, dilly bags, Ooyurkas (Fig. 16), shields, swords and ground edged axes (e.g. Khan, 1993, 1996, 2004).

8. Summary The study of plant microfossils from cultural deposits and from slate incised grinding stone fragments provides new information about Queensland rainforest occupation and the use of starchy plants. Importantly, starch and phytoliths are preserved in sediments in these open tropical rainforest contexts for at least 2000 years. The phytolith sequences demonstrate that this Eucalyptus pocket (Urumbal Pocket) was maintained and managed by fire for at least 2000 years. The high numbers of palm phytoliths in the sequence may be evidence of shelters constructed from Calamus sp. (Palms) as documented elsewhere (see Pedley, 1993; Memmott, 2007).

During late Holocene human settlement at Urumbal Pocket, toxic starchy nut processing was an important rainforest subsistence strategy. Starch from a range of toxic starchy nuts suggests that Urumbal Pocket, and perhaps Goddard Creek were wet season (summer) camps. The absence of Black Bean (C. australe) from the assemblages, a known important species and a winter ‘crop’ would be consistent with this interpretation.

13 Morahs, or incised slate grindstones surfaces played an important role in the routine processing of toxic starch nuts from the North Queensland rainforests. We have now confidently identified: E. palmerstonii, B. bancroftii, L. whelani, C. media, P. turneriana, S. amarus and L. hopei – all species that have been documented ethnographically as involving complex processing. The Murubun Shelter Morah fragment from the rainforest margin yielded a starch assemblage consisting of primarily rainforest species, plus species that are known to come from the rainforest edge – including Tacca leontopetaloides and C. media. The location of Murubun Shelter positioned people to exploit resources from both environments.

The data presented here supports Cosgrove’s (1996) thesis that exploitation of toxic starchy nuts was a critical factor in the permanent rainforest settlement in North Queensland. Human use and maintenance of particular patches within the rainforests allowed rainforest settlement and harvesting of specific high carbohydrate resources. The maintenance of the sclerophyll patch within the rainforest and the gradual changes observed at Goddard Creek are consistent with the principles of niche construction. These strategies effectively operated to “damp out variability in the availability of food, such that they could survive in a variable and changing world” (Laland and O’Brien, 2010). Niche construction enhanced the habitat of other species, such as small mammals and birds, while producing a more open ‘liveable’ environment as seen in the adjoining wet sclerophyll forest.

As in other regions of the world during the Pleistocene, rainforest occupation during the Holocene in Australia provides further evidence that rainforest peoples did not rely on food/resource exchanges with agricultural societies. Niche construction theory, as investigated here, has allowed us to explore how people interacted with and adapted to a rapidly changing world, to explore the antiquity of rainforest specific cultural practices and to begin to unravel the complex relationships between managed landscapes and cultural adaptations.

Acknowledgements It is important to acknowledge the support and mentoring by Jim O’Connell (and Jim Allen) to one of the authors (JF). Between the ‘two Jims’, JF would never have withstood the relentless barrage of criticism concerning the Cuddie Springs site, which she has been investigating most of her career. This paper is dedicated to you! The project was funded by an Australian Research Council Discovery Project grant awarded to Field and Cosgrove (2002-2004: DP210363), The University of Sydney and The University of New South Wales. Don Page and Michael Burnside provided technical assistance in the preparation of the samples. We are grateful to Rebel Elick and Bruce Gray (Australian Tropical Herbarium, Atherton) for advice and the provision of comparative reference material included in this study. Thanks also to the Queensland Museum for allowing us to sample the Morah collection, and especially to Pat and Alverio Croatto for their hospitality and for allowing us to sample their private Morah collections. Corinne Barlow is thanked for assistance with soil sample collection for phytolith analysis at Urumbal Pocket. The late Maisie Barlow and the Jirrbal Aboriginal community supported this project and gave permission for the excavations at Urumbal Pocket and Goddard Creek. We would like to gratefully note that Ron and Deanna Stager sustained us intellectually and physically during fieldwork.

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19 Family Species Common Name Altitudinal Range* Fruiting Season Cycadaceae Cycas media Cycad SL-1000m August-January Dioscorea bulbifera Hairy Yam SL-800m - Dioscoreaceae Dioscorea transversa Long Yam SL-1100m - Tacca leontopetaloides Polynesian Arrowroot Nr SL-900m - Castanospermum Fabaceae Black Bean Nr SL-840m March-November australe Beilschmiedia bancroftii Yellow Walnut Nr SL-1200m August-March Lauracae Endiandra insignis Hairy Walnut SL-1000m October-July Endiandra palmerstonii Black Walnut SL-1100 September - April December - Podocarpaceae Sundacarpus amarus Black Pine 600-1200m February November - Proteaceae Lasjia whelani Whelan’s Macadamia SL-1200m December Wild Almond, September- Rosaceae Prunus turneriana SL-1200m Almondbark January Bowenia spectabilis Zamia Fern SL-800m January -June Zamiaceae Zamia Palm, Hope’s Lepidozamia hopei Nr SL-700m May-June Cycad

Table 1 Economic species from the North Queensland tablelands rainforest, their recorded altitudinal limits and fruiting season. The list includes all those species relevant to this paper (see Pedley, 1993, see also Cosgrove et al., 2007). SL=Sea Level, *source: http/keys.trin.org.au, and Cooper and Cooper (2004).

20 Square Z3 Soil Description Munsell Colours Sediment Description Artifact-rich black 10YR 1/7 top Homogeneous and unconsolidated sandy Unit 1/Phase 3 loam 7.5YR4/6 base loam, fine grit throughout Transition Layer Light brown gritty soil with some orange 7.5YR 3/2 Phase 2 mottling Light coloured Increasingly gritty and less homogenous with Unit2/Phase 1 7.5YR4/6 loam depth, decomposing granite bedrock

Table 2 Urumbal Pocket sediment descriptions (after Ferrier and Cosgrove, 2012).

21 No. grains % identified of total Sample No. No. grains digitized identified grains digitized Urumbal Pocket Grindstone 7 2 29 Grindstone KD02-2002a 29 8 28 Murubun Shelter Grindstone 64 15 23 Goddard Creek Sediment 11 4 36 Urumbal Pocket Square O2 93 9 10 Urumbal Square S2 63 16 25 Urumbal Square Z3 122 26 21

Table 3 Numbers of grains digitized by grindstone sample and squares for the analysis showing the number of grains identified to plant taxa and the percentage of the assemblage attributed to specific plant taxa. We used a very conservative approach to identify true positives and it is likely this success rate could be further increased.

22 SAMPLE LRSa SRSb SSc Wrinkled / folded sphere VR / gran sphere Finely spiculate sphere Irreg rough spheroid lumpy globular Other dicot UNID MFPs various Palm - various sedge Poaceae short cells UNIDs Z3-1-P1 8.2 26.9 4.8 1.4 1.0 0.0 0.0 1.4 7.2 6.3 26.4 0.0 15.4 1.0 Z3-2-P1 6.4 15.8 5.4 0.5 4.4 0.0 4.4 2.5 5.4 2.5 35.5 0.0 15.3 2.0 Z3-3-P1 10.4 19.3 13.2 0.0 9.0 0.0 0.0 0.0 5.2 0.0 26.9 0.5 14.2 1.4 Z3-4-P1 7.4 30.0 11.8 0.0 5.9 0.0 0.0 0.0 3.4 0.5 30.5 0.0 10.3 0.0 Z3-5-P1 11.2 23.8 13.1 0.0 4.9 0.0 0.5 5.8 5.8 2.9 20.9 1.0 10.2 0.0 Z3-6-P1 0.0 20.1 9.6 0.0 2.7 0.0 3.7 3.7 5.5 1.8 40.6 0.5 11.0 0.9 Z3-7-P1 9.2 26.2 12.1 1.0 8.7 0.0 1.5 3.4 2.9 0.5 29.1 0.0 5.3 0.0 GC-1-K1 4.8 35.1 7.7 0.0 1.9 22.1 0.0 2.4 6.7 1.0 13.9 0.0 4.3 0.0 GC-3-K4 6.4 32.8 7.4 0.0 10.3 18.6 0.0 0.0 7.4 3.4 10.3 0.0 3.4 0.0 GC-5-K2 5.4 50.5 3.0 0.0 3.0 13.4 0.5 2.5 3.5 0.5 15.3 0.0 2.5 0.0 GC-7-K1 6.4 58.9 2.5 0.0 4.0 11.9 0.0 0.0 5.9 1.0 5.0 0.0 4.5 0.0 aLarge Rough Spheres; bSmall Rough Spheres; cSmooth Spheres

Table 4 Phytolith counts by relative contribution per sample.

23

Fig. 1. Location of sites discussed in text (after Cosgrove et al., 2007).

24

Fig. 2. The Urumbal Pocket site during excavations in 2003. The archaeology lies at the high water level mark of the Koombooloomba Dam in the Wet Tropics World Heritage Area in North Queensland. The site also lies adjacent to the old Tully River channel. The highly organic deposits that comprise Stratigraphic Unit 1 can be seen in the foreground square. Photo: J. Field.

25

Fig. 3. Section profile of Square Z3 at Urumbal Pocket (after Ferrier and Cosgrove, 2012).

26

Fig. 4. The Goddard Creek site (foreground) exposed during low lake levels at Koombooloomba Dam, Far North Queensland, 2002. Photo: J. Field.

27

Fig. 5. Incised slate grinding stones analyzed for ancient starch residues. (A) Urumbal Pocket excavation UP A3 SPIT 3; (B) Murubun Shelter surface find; (C) Koombooloomba Dam Surface Find KD02-2002a.

28

Fig. 6. Modern starch grain comparative reference material used in the geometric morphometric analysis of the starch microfossils examined in this study. (A) Beilschmiedia bancroftii (Family Lauraceae) has a starchy tree nut, and fruits from August-March. Compound grains are common, often <10 grains conjoined. Size range: 6.04–22.97 µm, n: 120. (B) Castanospermum australe (Family Fabaceae) usually contains up to 6 kernels per seed-pod. It fruits from March-November and contains simple and compound grains, as seen here. Size range: 4.89–13.87 µm, n: 157. (C) Dioscorea bulbifera var. bulbifera (Family Dioscoreaceae) is endemic to North Queensland. It has a starch tuber, simple grains which are very distinctive in shape. Size range: 6.37–60.77 µm, n: 206. (D) Dioscorea transversa (Family Dioscoreaceae) is also endemic to North Queensland, has a starchy tuber with large grains and eccentric hila. Size range: 11.65–43.70 µm, n: 103 (E) Endiandra insignis (Family Lauraceae) has a tree nut and fruits from October-July, it has simple grains with eccentric hila. Size range: 6.17–33.87 µm, n: 139. (F) Endiandra palmerstonii (Family Lauraceae) has a starchy tree nut, fruits from November-March and has simple grains with an eccentric hilum. Size range: 5.35–50.07 µm, n: 138. Photos: J. Field.

29

Fig. 7. Modern starch grain comparative reference material used in the geometric morphometric analysis of the starch microfossils examined in this study. (A) Bowenia spectabilis (Family Zamiaceae) is endemic to Australia with starchy seeds in the female cone, fruiting from November to March. Some grains are highly faceted from cell- packing, others are not. Size range: 4.35–12.87 µm, n: 135. (B) Cycas media (Family Cycadaceae), usually found in the dry country and fruits from August-January. It contains simple grains, many of which are highly faceted from cell- packing. Size range: 3.44–18.42 µm, n: 134. (C) Lasjia whelani (Family Proteaceae) produces a starchy tree nut (fruit). Grains have eccentric hila. Size range: 5.67–26.84 µm, n: 108. (D) Prunus turneriana (Family Rosaceae), has a tree nut (fruit), produced September-January with simple and compound grains (usually <10 conjoined). Size range: 6.58– 20.24 µm, n: 100. (E) Sundacarpus amarus (Family Podocarpaceae) is a tree nut that fruits from November to March, it has simple grains with a generally centric hilum. Size range: 3.21–17.89 µm, n: 182. (F) Tacca leontopetaloides (Family Dioscoraceae) has a starchy tuber, which has simple grains, some of these are highly faceted from cell- packing. Size range: 3.68–26.97 µm, n: 147. (G) Lepidozamia hopei (Family Zamiaceae) is endemic to Australia, the female cone has starchy seeds. Size range: 4.47–21.43 µm, n: 104. Photos: J. Field.

30 Dioscorea bulbifera

Dioscorea transversa

Endiandra palmerstonii

Lasjia whelani

Beilschmiedia bancroftii

Tacca leontopetaloides

Endiandra insignis

Prunus turneriana

Cycas media

Castanospermum australe

Bowenia spectabilis

Sundacarpus amarus

Lepidozamia hopei

35 30 25 20 15 10 5 0 Mahalanobis distance between group means

Fig. 8. Dendrogram for the MANOVA across area, perimeter and Fourier signature (components 0–4), the predictor variables of the optimal classifier, showing the Mahalanobis distance between the means of the species. Note that Sundacarpus amarus and Lepidozamia hopei were the most difficult to separate.

31 Confusion Matrix

Beilschmiedia bancroftii 77 0 0 1 0 0 13 0 0 3 0 0 2 80.2%

Bowenia spectabilis 1 54 11 5 0 0 5 3 0 11 5 6 12 47.8%

Castanospermum australe 3 6 95 14 0 4 7 2 0 4 19 18 22 49.0%

Cycas media 13 4 3 69 0 2 5 0 0 4 7 8 13 53.9%

Dioscorea bulbifera 0 0 0 0 199 0 0 5 2 0 0 0 0 96.6%

Dioscorea transversa 5 0 1 1 0 99 11 3 0 0 0 0 7 78.0%

Endiandra insignis 5 1 0 0 0 2 74 4 0 6 1 1 6 74.0%

Endiandra palmerstonii 5 0 0 0 1 0 1 94 3 0 0 0 0 90.4%

(Output Class) Lasjia whelani 0 0 0 0 6 0 0 15 103 2 0 0 0 81.7%

Predicted Species

Lepidozamia hopei 1 0 0 2 0 0 1 0 0 15 0 2 2 65.2%

Prunus turneriana 2 5 13 15 0 0 0 0 0 4 50 3 2 53.2%

Sundacarpus amarus 1 36 31 18 0 1 10 4 0 49 16 143 11 44.7%

Tacca leontopetaloides 7 5 3 8 0 10 12 8 0 6 2 1 70 53.0%

64.2% 48.6% 60.5% 51.9% 96.6% 83.9% 53.2% 68.1% 95.4% 14.4% 50.0% 78.6% 47.6% 64.8%

Cycas media

Lasjia whelani

Prunus turneriana

Endiandra insignis

Lepidozamia hopei

Dioscorea bulbifera

Bowenia spectabilis

Dioscorea transversa

Sundacarpus amarus

Endiandra palmerstonii

Tacca leontopetaloides Tacca

Beilschmiedia bancroftii

Castanospermum australe Reference Species (Target Class)

Fig. 9. The confusion matrix for the optimal classifier for the reference species used in the North Queensland rainforest study. The target class is the actual (known) reference species, and the output class is the species predicted by the classifier. The numbers of grains classified for each ‘target-output pair’ of the reference set are reported in each square. The accuracy for each output class is shown at the end of each row and for each target class column at the bottom. Note that the reference set contained different numbers of grains of the different species (Table 3). For the purposes of classifying unknown grains, we need to know how well the classifier correctly picks the right species. In this case you want to know how often the prediction was correct. For example, if you look across the row for Dioscorea transversa, you can see that 78.0% of the grains that the classifier predicts are D. transversa were, indeed, D. transversa. This gives one indication of how confident you can be in the prediction (other measures include the cross- fold validation error and PPV, described in the text). A classifier is tested in a forward manner by taking each (known) grain of the reference set in turn (Target) and using the classifier to predict the species (Output). A summary of how successful this process was can be determined by looking at the percentages in the last row. For example D. transversa was correctly identified in 83.9% of the cases when D transversa was presented to the classifier. You can also see whether there are common misclassifications within the classifier. For instance, reading across the row for Sundacarpus amarus, you can see that whilst 143 grains were correctly identified from S. amarus, 49 were actually Lepidozamia hopei, 36 Bowenia spectabilis and 31 Castanospermum australe. These misclassifications can often be resolved by expert identification of these grains, using subjective features not utilised by the classifier, however it is useful to know which species are harder to resolve.

32 All Grains 0.7

0.6

0.5

0.4 CVE 0.3

0.2

0.1 Species Average 0

Lasjia whelani Cycas media Endiandra insignis Lepidozamia hopei Prunus turneriana Dioscorea bulbiferaDioscorea transversa Sundacarpus amarusBowenia spectabilis Endiandra palmerstoniiBeilschmiedia bancroftii Tacca leontopetaloides Castanospermum australe

Fig. 10. The cross-fold validation error (CVE) of the comparative reference species. The CVE is also shown in gray in the background. The darker the gray, the greater the CVE, and the less confident the identification/separation from its closest species (e.g. Sundacarpus amarus vs Lepidozamia hopei). The threshold level of 0.3, above which the prediction is not confident, is shown as a red dashed line, and the average CVE of the reference species is shown as a black line.

33 Square O2 Square S2 Square Z3 4 10 4 3 8 3 6 2 2

5 cm 5 cm 4 5 cm 1 2 1 0 0 0

5 1 4 4 3 3 2 2 10 cm 10 cm 10 cm 1 1 0 0 0

2 2 20 15 1 1 10 15 cm 15 cm 15 cm 5 0 0 0

10 4 1 8 3 6 2 No Identifications 4 20 cm 20 cm 20 cm 2 1 0 0 0

1 1 2

No Sample No Sample 1 25 cm

0 0 0

1 2 1

No Sample 1 30 cm 30 cm

0 0 0

1 2 1

No Sample 1 37 cm 35 cm

0 0 0

Lasjia whelani Cycas media Lasjia whelani Cycas media Lasjia whelani Cycas media Endiandra insignisPrunus turneriana Endiandra insignisPrunus turneriana Endiandra insignisPrunus turneriana Dioscorea transversa Dioscorea transversa Dioscorea transversa EndiandraBeilschmiedia palmerstoniiTacca bancroftii leontopetaloides EndiandraBeilschmiedia palmerstoniiTacca bancroftii leontopetaloides EndiandraBeilschmiedia palmerstoniiTacca bancroftii leontopetaloides

Fig. 11. Plots (21) of starch identifications from three squares at Urumbal Pocket by depth. Each plot represents a sample from a specific depth from a single excavation square. The three excavated squares are labeled across the top and sample depths are on the far left, usually at 5 cm intervals. For each individual plot the x axis shows the species identified, and the y axis shows the number of starch grains per species. Within the plot area two different types of confidence levels are defined. The species are ordered left to right based on how easy it is to separate one species from any other, with those to the left of the dotted line having the most reliable identifications, with a CVE less than 0.3. From bottom to top within the histograms the colored area represents the number of grains visually confirmed and the un-colored areas represent the number of grains that meet the morphometric criteria but are less clearly identifiable visually.

34 Urumbal Pocket: A2-SP3

1

0

Sylvania Creek: KD02_2002a 10

8

6

4

2

0

Murubun Shelter: Surface Grindstone 20

15

10

5

0

Lasjia whelani Cycas media Endiandra insignisLepidozamia hopei Prunus turneriana Dioscorea transversa Sundacarpus amarus Endiandra palmerstoniiBeilschmiedia bancroftii Tacca leontopetaloides

Fig. 12. Results of the geometric morphometric analysis of grinding stones from North Queensland. One sediment sample from Goddard Creek yielded starch grains and these are shown at the top of the figure. The remaining samples are grinding stones from private collections, excavated at Urumbal Pocket (A2-SP3) or surface gray-scale in the background. The validated classifications are shown in color, and the probable classifications in gray. The 0.3 CVE threshold, beyond which the predictions are less reliable, is indicated by a red dashed line. Those to the left of the line have CVE within the more reliable prediction range.

35

Fig. 13. Concentration of starch grains/100 g of sediment for squares O2, S2 and Z3 from the Urumbal Pocket sequence. A, Square O2; B, Square S2; C. Square Z3.

36

Fig. 14. Tilia graph of the phytolith sequence from Urumbal Pocket (Grimm, 2004). Note that the colors distinguish different ecological and taxonomic groupings. Depths and radiocarbon dates are on the y-axis. On the right, CONISS (stratigraphically constrained cluster analysis) shows sample similarity. The burned phytolith types on the right side of the diagram show a cyclical pattern of burning, which is related to the secondary growth taxa, in this case Euphorbiaceae. The overall decrease in tree/arboreal phytoliths at the top of the sequence is paralleled by an increase in grass species and burning.

37

Fig. 15. Tilia graph of the phytolith sequence from Goddard Creek (Grimm, 2004). The colors are the same as in Fig. 14, as are the location of date and depth information. The dominance of arboreal taxa is clear throughout this sequence, despite the increased evidence for burning at the top. It is consistent with Goddard Creek being located in the rainforest proper, in contrast to Urumbal Pocket. Burning is not related to secondary growth in this sequence, suggesting wood burning for cultural purposes. A CONISS analysis was not undertaken here because of the limited samples available for study.

38

Fig. 16. Example of an Ooyurka (t-shaped stone) from the North Queensland rainforest. Ooyurkas are often found in similar contexts to the Morah stones analyzed in this study. Image: Richard Cosgrove.

39

Fig. 17. Biplot of Principle Components 1 and 2 for Urumbal Pocket [Z3] and Goddard Creek. The distribution shows that Urumbal Pocket phytoliths, and hence vegetation, are very different from Goddard Creek and that there are strong internal differences within the Urumbal Pocket sequence.

40