Land Snail and Soil Analysis in Atoll Archaeology

Home , Lamellidea, Melampus (gastropod), Partula remota

With Special Reference to Atafu Atoll, Tokelau Islands

Adam Thompson

A thesis submitted for the degree of Master of Arts at the University of Otago, Dunedin New Zealand

February 2010

Abstract

In 2008 and 2009, the author spent a month on the island of Atafu as part of the To- kelau Science, Education, and Research program co-directed by David Addison and John Kalolo. During this time he assisted in archaeological excavation, collected land snails and soil samples, made a ﬁlm, and became a part of an atoll village that welcomed him kindly into all facets of their community.

Atolls are commonly seen as marginal environments on the edge of sustainability. In many ways this is true: their soils are poor, their small land areas are susceptible to inundation by large storms, and most are still only reached by long boat trips remov- ing them from contact with the modern world. But these same characteristics have been positives. Their small land areas mean that everyone lives in one tight-knit community. Their remoteness has preserved their culture. Their poor soils mean that only those determined may settle. And once settled these soils gain from the successive gardening activities that build the island up and add organic material and vitality to its base. From a low sandy, salty lump of coral in the middle of the ocean, these islands have become fertile oases through the many generations that have tended them. They are gardens; nothing exists on them that has not been modiﬁed by those that have lived on them.

This study looks deeply at the atoll, beginning with its young geology, its speciﬁc biogeography, its early archaeology, and its ecology. From these different sciences assumptions can be made about its land snail fauna. Natural colonizers had to be highly salt-resistent and able to arrive quickly, but most would be introduced by gardening activities. By careful sampling from the surface of the village islet, from the outer islets, and from column samples throughout its stratigraphy one can distinguish which species are natural, which inhabit the gardens in the poor soil, and which inhabit the gardens in the good soil. One can use these inferences to make statements about the environment of the past. And, in small ways, one can see how the land transformed from a low marginal island into a vital oasis full of splendid people.

Table of Contents

Abstract ii Table of Contents iii List of Tables vi List of Figures vii

Introduction 1 Signiﬁcance 2 Chapter Outline 4

Chapter 1: Atoll Geology and Sea Level Rise 7 Historical Debate on the Formation of Coral Atolls 7 Highstand on Paciﬁc Atolls 15 Summary 19

Ch 2: Land Snail Biogeography 20 Land snails in Geologic Time: Continental vs Island species 23 Continental Species 23 Minute Island Species 24 Land Snails of the Paciﬁc 27 Summary 31

Chapter 3: The Beginning of Atoll Archaeology 32 Nukuoro Atoll, Eastern Caroline Islands 32 Ulithi Atoll, Western Caroline Islands 35 Kapingamarangi Atoll, Eastern Caroline Islands 37 Kwajalein Atoll, Marshall Islands 40 Summary 43

Ch. 4 The Vegetative History of Atolls: Marshall Islands case study 44 Zones of Vegetation and Soil Development 44 Human Ecology Studies in the Marshall Islands 48 Archaeology in the Marshall Islands 52 Summary 56

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Chapter 5: Methodology 58 Questions 58 Field Research 60 Sample Unit Descriptions 63 TU-1: Deeply stratiﬁed (600 BP to modern) 63 TU-2: House platform (400 BP to proto-historic) 64 TU-4, 5, 6: Burials 65 TU-7, 8: Settlement or Re-settlement 65 Non-archaeological samples 66 Test Procedure 68 Sample Preparation 68 Land Snail Extraction and Soil Particle Size Preparation 69 Land Snail Analysis 69 Soil Particle Size Field Test 70 Soil Test Sample Preparation 70 Soil Particle Size Laboratory Test 71 Organic Matter Test 71 Soil pH Test 72 Systematic Review 73 Terrestrial Snails of Atafu Atoll, Tokelau Islands 73 Marine Snails Identiﬁed within the Study 79 Surface survey of modern snails 82 Survey of Uta, the outer islets 84

Chapter 6: Results 86 TU-1: Deeply Stratiﬁed 86 TU-2: House platform 89 TU-4,-5,-6: Burials 94 TU-7,8: Settlement or Re-settlement 98 100 Year-old Progradation 103 Malo’s Yard 106 Schoolyard 109

Conclusion 113 Thesis Summary 113 Historical Ecology of Atafu Atoll 116 Closing Statements 117

Acknowledgements 119 Tokelau and the Paciﬁc 119 University Assistance 120 Friends & Family 123

Reference List 124

Appendix A: An assessment of the reliability of the land snail field test 141 Appendix B: An assessment of the reliability of the soil particle size field test 143 Appendix C: Results of the Horiba LA-950 laser diffraction particle size test 147 Appendix D: Pulaka Pit Test Core 155 Appendix E: XRF testing 157 Appendix F: Preliminary charcoal identification 159

List of Tables

Table 1-1: A Record of Central Pacific Mid-Holocene Sea-level Highstands 16 Table 2-1: Fossilized Land Snails found in the Marshall Islands 27 Table 4-1: Results of Hainline (1965) 49 Table 4-2: Results of Rosendahl (1987) 52 Table 5-1: Surface Samples of Modern Land Snails 83 Table 5-2: Surface Pinch Samples of Modern Land Snails 83 Table 5-3: Land Snail Samples from Uta 85 Table 5-4: Land Snail Samples from Uta 85 Table 6-1: Results from TU-1 88 Table 6-2: TU-2 Particle Size Results 91 Table 6-3: TU-2 Soil Descriptions 91 Table 6-4: TU-2 Snail Results 91 Table 6-5: TU-2 Land Snail Results 92 Table 6-6: TU-2 Marine Snail Results 92 Table 6-7: Profile Alignment of TU-1 & TU-2 93 Table 6-8: TU-4 Particle Size Results 96 Table 6-9: TU-4 Soil Descriptions 96 Table 6-10: TU-4 Snail Results 96 Table 6-11: TU-4 Land Snail Results 97 Table 6-12: TU-4 Marine Snail Results 97 Table 6-13: TU-8 Particle Size Results 100 Table 6-14: TU-8 Soil Descriptions 100 Table 6-15: TU-8 Snail Results 100 Table 6-16: TU-8 Land Snail Results 101 Table 6-17: TU-8 Marine Snail Results 101 Table 6-18: Profile Alignment of TU-1, TU-2, TU-4 & TU-8 102 Table 6-19: 100YR Particle Size Results 104 Table 6-20: 100YR Soil Descriptions 104 Table 6-21: 100YR Snail Results 104 Table 6-22: 100YR Land Snail Results 105 Table 6-23: 100YR Marine Snail Results 105 vi

List of Tables continued

Table 6-24: MALO Particle Size Results 107 Table 6-25: MALO Soil Descriptions 107 Table 6-26: MALO Snail Results 107 Table 6-27: MALO Land Snail Results 108 Table 6-28: MALO Marine Snail Results 108 Table 6-29: SCHOOL Particle Size Results 110 Table 6-30: SCHOOL Soil Descriptions 110 Table 6-31: SCHOOL Snail Results 110 Table 6-32: SCHOOL Land Snail Results 111 Table 6-33: SCHOOL Marine Snail Results 111 Table A-1: Comparative Results of Land Snail Analysis, TU-4 & TU-8 141 Table A-2: Comparative Results of Land Snail Analysis, 100YR 141 Table A-3: Comparative Results of Land Snail Analysis, MALO 142 Table A-4: Comparative Results of Land Snail Analysis, TU-2 142 Table A-5: Comparative Results of Land Snail Analysis, SCHOOL 142 Table B-1: Comparative Results of Particle Size Field Test, TU-2 143 Table B-2: Comparative Results of Particle Size Field Test, TU-4 144 Table B-3: Comparative Results of Particle Size Field Test, TU-8 144 Table B-4: Comparative Results of Particle Size Field Test, 100YR 145 Table B-5: Comparative Results of Particle Size Field Test, MALO 145 Table B-6: Comparative Results of Particle Size Field Test, SCHOOL 146 Table D-1: Results from the Pulaka Pit Test Core 156

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List of Figures

Figure 5-1: Map of the Central Pacific Islands 60 Figure 5-2: Map of Atafu Atoll showing the locations of Sample Units 63 Figure 5-3: Introduced Land Snail Species from Atafu Atoll 75 Figure 5-4: Introduced Land Snail Species from Atafu Atoll continued 76 Figure 5-5: Introduced Land Snail Species from Atafu Atoll continued 77 Figure 5-6: Native Land Snail Species from Atafu Atoll 78 Figure 5-7: Marine Species Identified from Atafu Atoll 79 Figure 5-8: Marine Species Identified from Atafu Atoll continued 80 Figure 5-9: Illustrations of Snail Shells to a Common Scale 81 Figure 6-1: Profile of TU-1 86 Figure 6-2: Results from TU-1 88 Figure 6-3: Profile of TU-2 89 Figure 6-4: Results from TU-2 91 Figure 6-5: Results from TU-2 continued 92 Figure 6-6: Profile Alignment of TU-1 & TU-2 93 Figure 6-7: Profile of TU-4 & TU-6 94 Figure 6-8: Results from TU-4 96 Figure 6-9: Results from TU-4 continue 97 Figure 6-10: Profile of TU-8 & TU-7 98 Figure 6-11: Results from TU-8 100 Figure 6-12: Results from TU-8 continued 101 Figure 6-13: Profile Alignment of TU-1, TU-2, TU-4, & TU-8 102 Figure 6-14: Profile of 100YR 103 Figure 6-15: Results from 100 Year-old area 104 Figure 6-16: Results from 100 Year-old area continued 105 Figure 6-17: Profile of Malo’s yard 106 Figure 6-18: Results from Malo’s yard 107 Figure 6-19: Results from Malo’s yard continued 108 Figure 6-20: Schoolyard Profile 109 Figure 6-21: Results from Schoolyard 110 Figure 6-22: Results from Schoolyard continued 111

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List of Figures continued

Figure C-1: Example of Horiba LA-950 Data Graph Interpretation 147 Figure C-2: Results from the Horiba LA-950, TU-2 149 Figure C-3: Results from the Horiba LA-950, TU-4 150 Figure C-4: Results from the Horiba LA-950, TU-8 151 Figure C-5: Results from the Horiba LA-950, 100YR 152 Figure C-6: Results from the Horiba LA-950, SCHOOL 153 Figure C-7: Results from the Horiba LA-950, MALO 154 Figure D-1: Pulaka Snail 155 Figure D-2: Results from the Pulaka Test Core 156

Introduction

“Fiji, Samoa, Tonga, Niue, Rotuma, Tokelau, Tuvalu, Futuna, and Uvea formed a large exchange community in which wealth and people with their skills and arts circu- lated endlessly...Only blind land-lubbers would say that settlements like these, as well as those in New Zealand and Hawaiì, were made through accidental voyages by people who got blown off course - presumably while they were out fishing with their wives, children, pigs, dogs, and food-plant seedlings during a hurricane.” (Hauòfa 1993:9)

Included in the large exchange community described above are two archipelagos of atolls, Tokelau and Tuvalu. The former will provide the setting of this study. The ex- cerpt is taken from Epeli Hau`ofa’s (1993) “Our Sea of Islands” in which he denies the derogatory and misleading Western perspective of the Paciﬁc islands as small, isolated and poor in favor of the Oceanic perspective of a network of interwoven communities spread across an ocean that, though it be the largest in the world, has connected those distant communities of capable, sea-faring Polynesians for three thousand years. It is in this same spirit that I here wish to promote atolls as more than the tiny fragments of land inhabited by unfortunate drifters, but by people who preferred to live on these unique islands as close to the sea as one can get.

Work by Di Piazza and Pearthree (2001a) have shown interaction between the atolls known as the Phoenix Islands and the islands of Samoa, the Marquesas, and the Southern Cooks based on the presence of basalt chemically identified to sources from these three island groups found in excavations on Manra, Kiritimati, and Tabuaeran atolls. Thus these islands were far from isolated and may be added to an exchange community larger than that described above. Di Piazza and Pearthree (2001b, 2004) therefore take the perspective described by Hauòfa that these islands were purposefully settled within a sphere of interaction whereby each atoll offered a something unique, whether it be gardens, birds and turtles, religion, or just a bit of respite during a voyage. These islands did not function as isolates but as ‘coral complexes’ (Alkire 1978) such as that described in the Caroline Islands surrounding Yap (Descantes 2005) and the atolls surrounding Mangareva (Weisler 1996). It is from this perspective that the true significance of Pacific atolls may be seen.

1 Signiﬁcance

Across the Paciﬁc a line of atolls may be observed spanning from West to East from the Marshalls to Kiribati and Tuvalu to Tokelau and the Northern Cooks ending in the Tuamotus. This line of atolls represents a signiﬁcant geographic area forming a boundary between the Western Polynesian islands of Fiji, Samoa, and Tonga and the Eastern Polynesian islands of the Societies, Marquesas, and Hawaii. Archaeological investigation has shown an extreme distinction in the period of settlement of these two areas, West and East Polynesia, separated by one to two thousand years (Kirch 1986). That this line of atolls should not play a role in the delayed expansion into East Polynesia would seem highly unlikely.

Determining the reason for the ‘long pause’ between these two waves of colonization has been the focus of prolonged debate. Initially, it was believed that the phenomena was only a product of poor preservation and that early sites were still left to be found (Irwin 1981). However, careful scrutiny of dates (Spriggs and Anderson 1993) left little doubt in the gap in the chronology. A distinction in the geography of the islands between West Polynesia, characterized by large, diverse archipelagos, and East Polynesia, made up of small, distant, resource-poor islands, has recently been promoted as a major factor in the gap in settlement (Thomas 2008).

This study includes the ability to navigate and settle remote atolls as a barrier to the settlement of East Polynesia. Lewis (1972) describes the traditional sailing route from Samoa to Pukapuka Atoll by ﬁrst traveling to the atolls of Olohega and Fakaofo. Addison (in prep, 2008) builds from this traditional knowledge to suggest that Tokelau and the Phoenix Islands played an integral role in the colonization of East Polynesia. Dating the initial settlement and subsequent development of the islands that make up this line of atolls is therefore necessary to evaluate the expansion of people from West to East Polynesia.

That these atolls may have only risen out of the water in the past one to two thousand years (Dickinson 2001, 2003, 2004) helps to further explain the delay in what was an otherwise impressively fast expansion. Addison and Matisoo-Smith (2010) give evidence of a group of Austronesian people other than Lapita moving across the Paciﬁc at this time. Hypothetically, it is the arrival of this culture that would have ﬁrst

2 introduced the knowledge on how to settle Paciﬁc atolls and allow East Polynesia to be settled.

Initial colonizers to atolls would discover a wealth of fish, sea birds, turtles, and coconut crabs, “yet permanent settlers would ultimately depend on terrestrial production for the bulk of their subsistence” (Weisler 1999:2). Thus the introduction of agricultural production may serve as a proxy for permanent settlement. While initial colonization will always be archaeologically difficult to recognize, it is establishment, as defined by Graves and Addison (1996), that is of greater concern in this study. It is only after permanent settlement has occurred that significant cultural development may take place and the identity of a people changes from where they came from to where they are.

Further, it is only after settlement that an island may serve as a trusted stepping stone for further voyaging, particularly on atolls where resources, especially freshwater are extremely limited and plants, particularly coconuts are a necessary component of survival. In addition to being a source of food and water, the coconut is capable of surviving within the strand vegetation at the edge of the land and water. The planting of coconuts would therefore provide the added beneﬁt of stabilizing the forces of erosion and giving permanence to an otherwise precarious landform.

Soil development on an atoll is generally limited with the bulk of the landmass composed of marine-derived calcareous sediments with only a thin A horizon present. The introduction of new plants, however, leads to the increasing development of an organic base on which a more diverse set of plants may be introduced (Stone 1951:2). Thus, though initial introductions may be limited to strand vegetation such as coconut and pandanus, the accumulation of organic material from such introductions, creates a more rich environment in which more demanding plants may be introduced such as bananas, breadfruit, and swamp taro. The latter is of particular interest as traditional cultivation practices speciﬁcally focus on creating an organically rich pit in which the plant may grow exhibiting an understanding of the soil’s limita- tion. Thus it follows that initial anthropogenic change to the environment allows for subsequent change in the future to the point that the modern island environment owes itself to the accumulation of many centuries of human activity.

3 Some have down-played the potential of atolls for documenting long-term environmental change due to their “environmental homogeneity, small island size coupled with low elevation, and periodic, often catastrophic disturbances” (Weisler 1999: 622). While this belief would seem true for change within the natural environment, it is clearly false for anthropogenic change necessary for human habitation. Contrarily, the environmental homogeneity presents anthropogenic change and introductions in stark relief to an otherwise stable background ecology. Instead of being a hindrance, this unique environment supplies a level of control demanded of scientiﬁc investigation. This study will attempt to do just that.

After World War II there was a small migration of trained European and American academics to Micronesia, Melanesia, some parts of Polynesia, and expanding university centers in New Zealand and Australia (MacLeod 2000).. As they began to cul- tivate this research frontier, it became both professionally strategic and perhaps intel- lectually obvious to argue that the remoteness and evident marginality of the Paciﬁc Islands were analytical virtues rather than career handicaps. The closed ecosystem of these islands allowed them to be modeled in a way that the open ecosystems of continental environments could not.

Zoologists have found a limited amount of diversity on atolls composed primarily of species introduced by man. To their studies these islands offer little to stimulate their discussion of speciation, but to archaeologists all of these species represent artifacts, commensal species introduced over the course of the island’s settlement. It is in the spirit of those early academics that a new look is taken at these introduced species to see what they can tell us about the atoll environment and the effects of man.

Chapter Outline

As it will be explained in chapter 1, the Pacific atolls arose only within the last millen- nium. Prior to their emergence they would have existed as large fringing reefs just below the surface providing wealthy fishing grounds and markers for sailing ships. Multiple day fishing trips are not uncommon today and would be expected to have occurred more frequently in the past when fishing resources were of greater importance. That some of these fishing expeditions would come across these submerged reefs seems indisputable. Slowly as sea level dropped these reefs would emerge out

4 of the water providing a platform for sand to collect and a small shifting beach for these ﬁshermen to camp should they wish.

As the sea level continued to drop and the land stabilized different species would naturally colonize these islands through drift. Strand species such as pandanus, coconut, and pisonia would form a canopy of trees beneath which an ecology would develop. Amongst these species would be land snails, among the most successful multi-cellular animals to evolve hundreds of millions of years ago. Their ability to colonize these newly arisen islands will be discussed in chapter 2. A few species would be able to colonize naturally by drift, but greater success would come to those introduced by the gardening activities by people.

Early Pacific archaeologists discounted atolls as landforms devoid of significant deposition and therefore incapable of containing archaeological deposits. Chapter 3 will summarize the early archaeology of atolls and follow the course by which these beliefs evolved ending with the discovery that evidence can be found for 1900 year old layers throughout the Marshall Islands. These dates mean that these atolls were being settled almost as soon as they arose. Thus they were well known about and a need for their settlement existed. As rich fishing grounds it makes sense that these islands would be colonized as soon as possible. The limiting factor for settlement then was not want of fish, but rather the ability to grow plants integral to a healthy diet.

As strand-line trees grow and die, organic matter accumulates and the soil grows more fertile. This leads to a zonation of vegetation whereby the center of the island develops the greatest amount of organic matter with the outside remaining sandy and poor. As will be explained in chapter 4, the size of the island and the amount of rainfall affects this soil development limiting the number of people that can survive on the island and thus limits the intensity of settlement.

The goal of this study is to propose a method in which to study the development of the soil and the zones of vegetation on atolls over time so as to provide an environmental context of the factors limiting population growth in which to better interpret archaeological materials. Land snails will provide the means for this assessment. As stated a few of these land snails would naturally colonize the newly arisen atolls through drift. But with such a short geologic history no species would have time to

5 become endemic to the island. The majority of species would then be introductions, accidentally brought by people as they created their gardens. It is this close association of species to gardening activity that makes them so valuable. Chapter 5 will outline the methods in which land snail analysis and soil analysis will be used to describe the environment of the past and the gardening activities of the people who inhabited the island. Chapter 6 shall provide results for this method from material gathered from Atafu atoll in the Tokelau Islands. Chapter 7 will provide conclusions and goals for future research.

6 Chapter 1: Atoll Geology and Sea Level Rise

In 1824, as part of the voyage of the Uranie, captained by Freycinet, Quoy and Gai- mard reported the finding that coral growth is limited to the upper 20 fathoms below sea level (Quoy and Gaimard 1824; referenced in Steers and Stoddart 1977). It is only within this depth that sufficient sunlight will reach. The acknowledgment of this confining principle made it difficult to explain the presence of deep sea coral atolls, which could not have grown from the depths 10 which they reached. The answer would be found a decade later in 1835 by the outcome of a separate voyage, that of the HMS Beagle, but would take much longer to prove.

Historical Debate on the Formation of Coral Atolls

Darwin’s subsidence theory was one of his proudest discoveries as he first constructed his theory off the coast of South America through pure deduction prior to vis- iting the Pacific atolls (Darwin 1958). Darwin observed that uplifting of South Amer- ica’s continental landmass along its western coast and postulated that an opposite trend of subsidence would also be possible. His observations of the Tuamotus and Cocos Island would confirm these theories. Lyell had come close in his postulation that the coral grew on submerged volcanic rims but with out the theory of subsidence it was necessary that all such volcanic craters lie at the same depth just below the surface, a possibility that seemed very unlikely (Lyell 1832:283-301 cited in Steers and Stoddart 1977). Darwin’s explanation was greatly welcomed by Lyell at its first public announcement (Darwin 1962).

Along his journey aboard the Vincennes during the U.S. Exploring Expedition of 1838-42, James Dana, the expedition’s geologist, learned of Darwin’s theories from a newspaper article during a brief stopover in Australia at the end of 1839 (Davis 1928:46). The expedition’s later travels to Fiji brought visits to three islands, Chichia, Matuka, and Nanuku, within Fiji’s eastern chain which he conﬁrmed Darwin’s theories by exhibiting a text-book progression of subsidence (Philbrick 2003:208). An ascent of Mt. Aorai in Tahiti, a highly dissected mountain, followed, in which Dana observed that, should subsidence occur the deeply dissected valleys would form the large em-

7 bayments seen on many such islands. This was evidence independent of Darwin’s observations that could further conﬁrm the theory of subsidence.

However, for the theory to be proven it had to be shown that such embayments were not formed by another process, that wave action and erosion had not actually destroyed the valleys leaving no evidence of their former structure. Dana would become the foremost proponent of Darwin’s theories making far more observations of reefs than Darwin and thus adding empirical evidence that was more and more demanded as the age of Science progressed. Yet, it was not until many bathymetric surveys had been made over the intermittent decades that Davis (1928), advocating the ‘home study’ of maps, could take up the argument and show that the South side of Tahiti still held a few submerged valleys not ﬁlled by deltas. However, beside Dana and Davis, little attention was given to submerged embayments.

Darwin’s theory was not fully proven until deep drilling tests were made in association with geological surveys of Bikini and Eniwetok atolls in the Marshall Islands as part of the nuclear test programs known as Operation Crossroads between 1945 and 1958 (Ladd 1973). These drillings were made under the guidance of the geologist Harry Ladd who saw the potential to prove Darwin’s theory once and for all. The military seized upon the opportunity for the potential public relations benefit in light of the controversial nature of their weapons test (Sponsel 2006). The first test drilling occurred in 1947 on Bikini atoll and reached a depth of 410 and 780 meters and showed only shallow water reef limestones throughout (Ladd et al 1948). This depth was well below any acceptable drop in sea level and begged explanation either through subsidence or an alternative theory. In 1951, volcanic rock was reached on Eniwetok atoll at 1,405 meters, confirming what was previously believed based on seismic tests in 1946 and 1950. Thus a large limestone cap had formed on top of the basalt basement beginning in the Eocene 30 million years ago based on fossils re- covered from the volcanic surface. This discovery not only finally proved Darwin’s theory but provided a time scale far greater than what those of Darwin and Lyell’s age were discussing. An abundance of pyroclastics, material that can only form when exploded into the air, dredged from the lower slope of Bikini atoll attests to eruptions at a time of shallow or emerged land (Ladd 1973:100) providing more sub- stantiating evidence.

8 Three horizons within the cores drilled represent periods of emergence showing that subsidence was intermittent with prolonged periods of stabilization shown by pollen and land snails. Leopold (1969) noted the presence of high-island forms within the pollen record that denoted the presence of an upland forest community. Land snails (Ptychodon) are also described as those favoring upland forests (Ladd 1958, 1968). Thus a dynamic history of starts and stops marked the course of the subsiding island instead of the steady movement expected of subsidence theory showing there was more going on than just one simple explanation. Within the 100 years between Dar- win’s theories and their veriﬁcation many geologists had come out in opposition of the subsidence theory espousing their own ideas for what became known as the Coral Reef Problem. Many of these theories would also prove to be true as well.

John Murray was a zoologist aboard the 1872-6 expedition of the Challenger who had been a last minute addition to replace someone who had fallen sick (Oldroyd 1996). Part of the expedition was to investigate the discovery of Bathybius, a pri- mordial ooze found in specimen bottles that Huxley, the renowned biologist, thought might be a food base for deep-water ecology. This was a time when the idea that the bottom of the ocean was a life-less void was being replaced by discoveries of ancient life forms remarkably similar to fossils. The Challenger expedition would ﬁnd, however, that Bathybius was the product of the ubiquitous ooze of planktonic skeletons mixed with alcohol.

The subject of Bathybius did however draw attention to the great quantity of plankton detritus and led to Murray’s theory of coral island formation. Murray took four samples by towing a twelve inch diameter sieve through half a mile of ocean at a depth of a few fathoms and extrapolated that the entire ocean volume a mile square and a hundred fathoms deep would contain over sixteen tons of plankton (Dobbs 2005). It was believed that the accumulation of the decaying skeletons on the sea floor along banks would form raised platforms on which coral would begin to grow. These beliefs were confirmed by observation of corals off the coast of Florida (Dobbs 2005). It was however, extremely difficult to prove such theories for the Pacific atolls.

These theories did however fuel the creation of alternative theories by showing examples of coral growth outside of subsidence theory. Rein’s observations of Ber- muda provided independent support of Murray’s hypothesis showing detritus accu-

9 mulation on a low-lying volcanic cone. It should be noted that Moseley, another zoologist on the Challenger, made the only observation that followed Dana’s submerged valley theory (Davis 1928:48).

The first borings to be made to investigate the underlying structure of a coral atolls in the Pacific were made in 1892-1896 at Funafuti during the voyage of the HMS Pen- guin (David and Sweet 1904). Daly verbalized the general agreement of the opposition that “the percentage of non-detrital coral rock in the Funafuti main boring appears to be much too low to prove the Darwin-Dana hypothesis” (1910:297). Several borings were made but only one, deemed the main boring, reached a significant depth of 1,114 feet with the other smaller borings matching its profile. Hinde reported that “the rock throughout the boring is either limestone or dolomitic in character; no silica has been observed, and there are no traces of pumice or other volcanic material” (1904:332). Hence no proof of the subsidence theory was supplied for the reason that they still needed to dig more than three times deeper. The interesting observation was that from the surface to 180 feet, the coral had undergone very little structural change except for the infilling by crystalline material leading one to believe it was of a relatively recent geological age. It was the formation of this coral that became the focus of a new theory.

An additional finding of the investigations at Funafuti was aptly described by Wharton (1897) that a flat foundation was observed beneath the atolls all at a common depth covering a much larger area than the coral atop it. That all these islands lay upon independent mounds made it difficult to believe that a common subsidence ac- counted for the same depth of all. Wharton instead explained the phenomenon as an effect of wave action which he believed could affect erosion even at a depth of 50 fathoms.

To explain this deep, pristine coral growth Daly deposited a possibility that had yet to be fully addressed, “a positive movement of sea level in the coral-reef zone” throughout the intertropical zone caused by the melting of Pleistocene glaciers in the northern and southern hemisphere (1910:298), which he deemed Glacial Control Theory. The origin of his theories were in fact as old as that of Darwin but had been excluded from sufﬁcient testing.

10 In the same year that Darwin published his theories, 1842, the American geologist Charles Maclaren in reviewing the work of Louis Agassiz, the originator of the theory for a glacial ice age, postulated that the formation and later melting of ice-caps would greatly affect the general sea-level (MacLaren 1842; Daly 1925; Oldroyd 1996). The concept was simple yet profound, the formation of glaciers would take large amounts of water from the world’s oceans lowering the sea level and the subsequent melt would raise sea level.

Though MacLaren’s theories would eventually prove more integral in the formation of coral atolls, he had to take a back seat to the fame of Darwin and Lyell who supported Darwin’s theory because it better fit his uniformitarianism. Lyell found it more difficult to accept theories concerning the ice age because it involved chaotic fluctuations of temperature within recent geologic time that sounded too much like the ca- tastrophist theories that Lyell opposed. At this early age of geology a division had arose between theories that fit within the biblical time frame that invoked major earth formation to catastrophic causes such as a diluge and those that promoted a much deeper time span in which the same effect could be attributed to small changes such as a stream (Herries-Davies 1989; Oldroyd 1996). The role of religion in this debate led the two theories to be seen as opposed to one another and it was not until much later that the two could be intertwined. Louis Agassiz, the founder of glacial ice age, was deeply part of the religious teleology surrounding the science of the day but was caught between competing theories and denigrated. His son Alexander would continue the studious pursuit with reserved respect for both sides.

Alexander Agassiz was an early proponent of Murray’s theories. At the turn of the century though he was focusing attention on the effect of currents in creating the wide platforms on which fringing and barrier reefs were seen to form. Lagoons were explained by the solvent action of particles charged with lime that decomposed shell over the course of many years (Agassiz 1899; Mayer 1915). Agassiz’s theories were based on his observations aboard the Albatross from 1899-1900. That all the platforms and lagoons of many different islands were all found at a common depth was only later noted by Daly, who provided a more plausible explanation. This phenomenon was explained by a lowered sea level that would lead to a prolonged period of low-level marine erosion that would eventually level the surface. A subsequent rise in sea level allowed corals to re-colonize (Steers and Stoddart 1977).

11 Based on observations of the magnitude of ice-sheet formation depicted in its effect on mountains throughout the world, Daly (1910) estimated that the sea-level must have been 150 meters (Penck 1894) below its present position. Modern measurements place the sea level 125 meters below modern sea level based on reef limestone cored off Tahiti (Nakada and Lambeck 1988; Tushingham and Peltier 1993; Dickinson 2001). According to Daly’s calculations this corresponds to an average thickness of 3,000 feet of ice or roughly one kilometer. These deposits were dated by Thorium-Uranium isotope and Carbon-14 to 22,000 years ago, after which the sea began to rise until 6000-4000 years ago when it reached modern sea level. At its lowest point the action of the waves over many centuries would have eroded away the ﬂat platforms on which the corals now lie. Throughout the period of sea level rise that followed corals grew steadily forming the deposits that were measured in the cores in Funafuti. It is the period following this sea level rise that becomes most important to coral atoll formation however for it is only in this time that the atolls form.

T. F. Jamieson (1865,1882) drew attention to the fact that evidence of the presence of glaciers was commonly accompanied by evidence of glacial submergence and post-glacial uplift. The simplest explanation was that the weight of the glaciers com- pressed the land beneath, which then uplifted due to elasticity after the glacial melt. He calculated that 3000 feet thick ice, an acceptable average thickness then and today, would produce 2000 million tons on the square mile. Observations of earthquakes had shown the Earth’s crust to be non-rigid and therefore under such great pressure it becomes understandable that the Earth should bend and rebound elasti- cally. This elastic uplift Jamieson believed would occur over a long period of time following glacial melt as a delayed response. This was the ﬁrst time that the weight of glacial ice was taken into account. It set a precedent for the later epiphany that the weight of the glacial melt water would also create an opposing force on the sea bed with a similar delay.

Jamieson’s evidence for submergence and subsequent uplift was a raised beach in Scotland which would became infamous from the many geological reports written about it. It was surmised that this beach would have once lay below sea level and then subsequently raised out of the water due to the uplift following deglaciation. Wright (1914) postulated a different explanation though, a sea-level fall. Wright noted that for a total distance of about 1,000 miles along the southern shores of Eng-

12 land, Wales, and Ireland a terrace may be traced continually standing uniformly 10- 12 feet above the present high-water mark.

Daly (1920:256) noted Wright’s finding and added his own of a similar terrace off the Northeast Coast of Canada and America as well as the findings of Mayor in American Samoa, A. Agassiz in the Tuamotus, and David and Sweet in Funafuti at the time the first borings were made. David and Sweet (1904:84-85) describe a raised reef that shows a six and a quarter feet drop in the shoreline as well as an area where disinte- grated coral material has been cemented by Lithothamnion algae that show an equal drop in sea level . Mayor (1920) reported the bench that encircles the island of Tutuila that is raised eight to ten feet sea level, with sea caves fourteen feet above. Agassiz (1903) found that nearly all the islands had been elevated to about the same height.

Moreover, all of these formations were found to date to the same geological period. Such a common geological formation across the Earth could only be attributed to a common fall in sea level. Daly references the work of Brogger (1901) who places this change in the Neolithic based on artifacts found in the beach deposits and esti- mates the temperature was warmer by two degrees celsius. Daly writes “the oscilla- tion as a whole would be but an incident in a series of climatic changes which began with the opening of the Glacial period” (1910:260).

Like Jamieson’s theories the weight of glacial ice was taken into account but in this case it was the weight of the melted water on the ocean floor and the delayed subsidence of the ocean floor. Daly was the first to address this issue writing, “the effect of the radial displacement of the sea-floor due to the weight of the water returned to the ocean, has not been considered by [the major proponents of glacial control theory]” (1925:286). While Daly believed the shift of sea-level would have had no effect on the islands far from the continents because they would be carried down with the sea floor he made special note that many volcanic islands of the deep sea (American Samoa, Tuamotus, and Funafuti) show emergence that proves their stability. This leads Daly to doubt that the shift was caused by sea-floor displacement. Later theories resolved this conflict by concluding that the displacement of the sea floor affected areas differentially, with greater affect at higher latitudes near the focus of glaciation, a feature that would be noted by Clark et al (1978).

13 A great deal of research since then has gone into arranging the many different variables affecting isostatic change into a proper formula that can explain all the meas- urable differences in sea level observed around the world. The level of detail these reports go into is not necessary for this paper. What is important is that a common sea level fall is noted and its effects on the formation of atolls is understood.

In 1930 Gardiner put forth the elevation-erosion theory which was notable in that it accepted the three differing theories that preceded him as autonomous foundation building mechanism: Murray’s accumulation of sediment, Agassiz’s submarine erosion, and Darwin’s subsidence (Dobbs 2005:250). This direction was also taken by Ladd and Hoffmeister who simplified everything into the antecedent platform theory that said, “any bench or bank at the proper depth within the circum-equatorial coral reef zone can be considered a potential reef foundation” (1936:74). Thus the reefs of Florida which had accumulated as Murray described, the deep sea atolls of the Pacific could form as Darwin and Dana held, and the flat platforms could be explained by the action of waves. However, Wharton, Agassiz and Gardiner suffered from a need for currents that could carve away platforms up to 150 fathoms deep, yet still allow coral growth. Daly’s glacial control theory effectively replaced theirs by bringing the waves down with sea-level fall to act in the ways that Agassiz and Gardiner could not quite explain. Indeed, all these three theories apply.

That Darwin’s deduction of the phenomenon of subsidence was proven to be correct after 100 years of skepticism exempliﬁes his genius, an ability to see phenomenon on a scale of 30 million years in a collection of a few observations. Such a capability rendered him a prophet in an age of Natural Theology. Yet his theory rested on the strength of coral to survive for so long without understanding exactly how it continued to form. That he could only observe coral growth within a few thousand years while subsidence worked on the order of millions of years weakened the ability of other’s to accept his leap. It was not until Daly explained the successive rise and fall of sea level that a mechanism for the continued cyclical growth of coral was understood and its power to survive could substantiate Darwin’s faith. Daly was to Darwin what quantum mechanics was to general relativity.

14 Highstand on Paciﬁc Atolls

In 1967 the CARMARSAL Expedition to Micronesia was made to resolve the discrepancies of a eustatic sea-level that was being measured at many different heights around the world. At this time the hydro-isostatic drawdown of ocean water to ﬁll the voids left by a deformed sea ﬂoor following the shifting weights of glacial ice melt, now called equatorial ocean syphoning, was not well understood (Dickinson 1999). This expedition should remind one of the Challenger voyage where little notice was made of submerged valleys though plenty of opportunities for their observation existed. But, like Louis Agassiz’s demonstration of glaciation, little evidence would be noticed until the theory was fully realized, after which repeated cases would come to light. Thus though David and Sweet (1904) had described evidence of a highstand sea-level the overwhelming evidence was yet to be seen.

Raised reef of one to two meters above sea level was reported by the CARMARSAL Expedition (Shepard et al 1967; Curray et al 1970; Newell and Bloom 1970) but as few corals or Tridacna clam shells could be conclusively found to be in growth position it was assumed that it was a storm deposit that all coral accretions occurred within the modern intertidal range, which tends to be extreme in that part of the Paciﬁc. These deposits were dated to 2500-3000 BP. This is unquestionably the same deposit that would be found to give proof to the Holocene highstand but for the time a contrasting interpretation persisted. Greater understanding of the theories be- hind sea-level change and an understanding of the cementation of corals would change the minds of geologists. Similar misconceptions would mark the initial archaeological projects on atolls where areas raised by hundreds of years of midden deposit would be misidentiﬁed as storm deposits.

Schofield (1977) rebuked the CARMARSAL Expedition’s conclusions “that there was no higher than present Holocene stand sea level” by returning to Funafuti and other islands of the Ellice (Tuvalu) and Gilbert (Kiribati) groups to find evidence of such a highstand. Schofield measured areas of raised biohermal reef rock in growth position that could have only formed under conditions of a raised sea level, as both the growth of the corals and its cementation by algae require submergence. Imbedded Tridacna clam shells were used to date the highstands as it was surmised they should contain the least contamination and give the most proper dates. Schofield’s

15 most outstanding find was a 2.4 meter find on Butaritari atoll dated to approximately 2750 BP. This was found to match findings by David and Sweet (1904) of Porites coral heads raised four feet above high tide which would correlate to 2.3-2.6 meters above low spring tide (Schofield 1977:519). Schofield’s statements were strengthened by findings the previous years at Enewetok Atoll of a high stand more than a meter (Tracey & Ladd 1974; Buddemeier et al 1975).

Though the CARMARSAL Expedition had failed to provide conclusive evidence in Funafuti it did publish evidence of a 1.8 meter sea level rise in Guam (Curray et al 1970). Yonekura et al (1988) would add to this their findings on Mangaia of an equal highstand at about the same period. These findings have been combined in Table 1.1 below. They would find their ultimate expression with the work of Dickinson at the turn of the century.

Table 1-1: A Record of Central Paciﬁc Mid-Holocene Sea-level Highstands

Publication Islands 2nd millenium BC (3000- 1st millenium BC (2000-3000 1st millenium AD (1000-2000 4000 BP) BP) BP)

Dickinson Funafuti +2.2 to +2.4 ?BP 1999 Majuro +2.3 to +2.4 ?BP

Schoﬁeld Gilbert +1.8 to +2.1 3460-3580BP +2.25 to +2.4 2690-2830BP +1.3 to +1.65 1520-1620BP 1977 Islands +1.5 to +1.8 2190-2440BP

Curray et al Guam, +1.4 to +1.8 3150-3650BP +1.5 2685-2920BP 1970 Marshalls

Yonekura et Mangaia +1.7 4000-3400BP +0.4 to +0.5 1320-1740BP al 1988

Tracey & Enewetak +1 plus 3290-4360BP Ladd 1974 Atoll

David & Funafuti +2.4 ?BP Sweet 1904

The existence of high stand coral reef on many low-lying Paciﬁc atolls could only occur under the conditions of raised sea level or uplifting of land. In all cases effects of subsidence and uplift had been tested and found to be negligible. Additionally, it is far more likely and accepted that a common sea level rise should affect all these islands in comparison to common geological activity. All of these studies show a common highstand approximately 3000 years ago with a subsequent decline in sea level to present with stabilization at 2000 BP.

16 The conclusions found have also been addressed by many other studies as well but not in as ﬁne a detail. The common trend is a raised sea level of about 1.5 meters between three and four thousand years ago. This transgression known as the Flan- drian Transgression culminated at approximately 2.3 meters around the turn of the millenium (ca 2900 BP) at which point the sea level returned to its previous 1.5 meter height (Schoﬁeld 1977). This prolonged period allowed the growth of corals for which these elevations were measured. At 2000 BP sea level began to regress beginning the erosion of the coral growth from the previous two millenia.

Differences in ﬁndings between islands may be attributed multiple factors. First, the differential growth of corals between warm tropical waters at low latitudes and cooler temperate waters at higher latitudes mean that less productive coral growth may show lower sea levels than actually existed. Secondly, differences in sea level rise associated with the slow process by which fresh glacial water mixes with salty ocean water means that sea level rises earlier at higher latitudes closer to sources of glacial melt. This process was termed ‘equatorial ocean syphoning’ by Mitrovica and Peltier (1991) with more equations to explain it than are required in this paper.

Schoﬁeld (1977) measured a 1255 year difference between sea level maxima of the Flandrian Transgression between northern New Zealand and the atolls of Gilbert and Ellice Islands. Clark et al (1970) predicted a two meter rise at 5000 BP. The data show such a rise occurring a millennia and a half later representing the lag time caused by the process of surface water circulation (Pisias 1975). Thus sea level rise clearly effects islands of different latitudes differentially though predictably.

Mitrovica and Milne (2002) provided an additional mechanism to explain differential sea level fall based on the work of Walcott (1972) who cites Daly (1925) as the orgin- ial progenitor of the theory, “that changes in surface load over the oceans because of eustatic changes in sea level would deform the earth” due to the slow relaxation of tectonic plates beneath the new weight of water above it. Because of variations in the ﬂexibility of tectonic plates across the Paciﬁc, sea level fall would occur differentially over different plates. Data from the Tuamotus has provided repeated measurements at a lower level below one meter with a concentration of heights at 0.7-0.9 (Pirazzoli and Montaggioni 1986, 1988; Pirazzoli 1987; Pirazzoli et al 1987, 1988).

17 Additionally, the Tuamotus may only have formed as stable land surfaces within the past millenia or less.

Within this scheme of ﬂuctuating sea level, three scenarios are possible at any one time...

• Rising sea level would drown the growth of atoll land formation while stimulat- ing coral growth to the level of low-tide similar to the effect of subsidence.

•Stable sea level would lead to the formation of shifting sand cays based on the existence of atolls in areas that show little sea level change such as the Carib- bean Sea (Stoddart and Steers (1977).

• Declining sea level would cause the reef platform to emerge, stimulate the erosion of coral reefs and the formation of table foundations on which sediment would collect leading to the growth of motus.

The effect of rising sea level is of greater concern given the current state of Global Climate Change. Expected sea level rise would inundate the Paciﬁc atolls (Woodroffe 2007). Indeed this is a reason for the present project - to provide a method to quickly study these islands before their disappearance.

The effect of a stabilized sea level is applicable to the time of the Flandrian Trans- gression which was found to reach its maximum in the Gilbert Islands at 2900 BP (Schofield 1977). Thus the life of Pacific atolls may be placed between 3000 BP and present if it can be proven that significant accumulation of sediment occurs during a stable sea level. If a significant drop in sea level is deemed necessary for atoll formation than the timing of atoll emergence may be pushed forward closer to 2000 BP when the first reefs would emerge out of the water.

Schofield looked more deeply at the effect of sea level fall as it concerned the colonization of the Pacific atolls he was studying specifically. Schofield stated that “because there has been a net fall, there has also been a net progradation” (1977:531). He goes so far as to say that onshore deposition and permanent islet growth may not have occurred until after the transgression that he dated to 2760 BP. The coinci- dence of this date with the earliest settlement of Micronesia and Polynesia led Green & Schofield to begin preparations of an article on the subject. Unfortunately the arti-

18 cle would never be published and it would not be until 2003 that Dickinson would finally address the issue specifically following Schofield’s initial thoughts.

Dickinson (2003, 2004) made the most explicit statements concerning the effect of sea-level on the formation of coral atolls based on calculations of the crossover date when the high tide mark of the present sea level fell below the low tide mark of the Holocene high-stand. It is at this time that the cemented paleoreef would have emerged from the water and a firm basement for the foundation of atoll development would be present. Prior to this time only a shifting sand cay would form that would be too unstable for permanent habitation and the development of archaeologically intact layers. It was not until the permanent foundation had emerged that the motu, a proper Pacific atoll, could form. Because sea-level fell differentially contrasting cross-over dates are seen around the Pacific. Dickinson (2003) found that these cross-over episodes progressed across the Pacific at the same rate that the Lapita people, the earliest Polynesians, migrated across the Pacific. That the Lapita people focused their settlements on low-lying areas near the water would explain the syn- chronism with the appearance of emergent platforms. It is worth hypothesizing that emergence could have given greater access to reef fish and allowed for more productive methods of net-fishing.

Summary

Daly (1925) was the first to draw attention to the fact that a relatively recent, worldwide sea level fall would affect human habitation along coasts and harbors and would be the concern of archaeologists. In addition, Daly was the first to draw attention to the effect of the weight of glacial melt water on the earth’s crust, to place the late holocene highstand at 3,500 years, and resurrect the theories of Charles MacLaren on the effect of glaciation on sea level to propose his Glacial Control Theory that effectively explained the minutiae of atoll formation beyond the general theory of subsidence. In light of all the theorists that have contributed to the debate on the Coral Reef Problem, perhaps none have done more then and now towards creating a solid theory on which to resolve discrepancies of observable facts. And so I would leave the final words to be his...

19 In fact, it is an open question whether the atoll archipelagoes do not represent a highly exceptional set of conditions, such as have very seldom prevailed in the history of the globe. (Daly 1910:308)

The significance of this statement is great. It is not coincidental that the expansion of people across the Pacific occurred during this unique time in history when these atolls formed. The expansion of people into East Polynesia may well be interlinked with the appearance of these unique landforms as stepping stones across an otherwise unnervingly enormous sea (Dickinson 2003). As will be discussed in greater detail in chapter 3 and 4, evidence exists to suggest that people colonized these islands as soon as they appeared. In the Marshall Islands hearths have been dated to 1900 BP suggesting that they were being occupied even before the crossover date. That they were being occupied so soon shows them to be of great importance, filling a needed role by their sudden appearance.

But for now let us ask how other species might naturally colonize these newly formed islands, what kind of ecology would be waiting for the ﬁrst settlers, and equally important what kind of species were incapable of naturally colonizing the Paciﬁc atoll and depended on human settlement to introduce them.

20 Ch 2: Land Snail Biogeography

Fundamental to the study of evolutionary change is the relationship of fossils, relics of a geologic past, to extant taxa living within the modern Age of man (Solem 1973). Though interconnected by their thread of time the study of these two specimens, fossils and their living descendents, represent two distinct perspectives.

Fossils are specimens selected by random conditions of preservation, dependent on geologic processes to reveal outcrops of rock containing those fossils, and the concentrated effort of scientists to ﬁnd and record the species. The outcome is a miniscule sample ranging over vast expanses of time. The record selects for species that extend across this time scale; species that have maintained a stable existence. The foreshortened lives of species that have come and gone over the course of a thousand years may be altogether lost in this record.

Extant species, on the contrary are characterized by present day observations that have been recorded over the course of a few hundred years of concentrated study - a large body of research covering a miniscule period of time. Within this time scale, observations of extant species are framed within an ecology that is under constant ﬂux and therefore gives rise to changes that more likely will not be able to exist over a geological time scale. It is only from this perspective that the true nature of evolution can be seen. A beautiful sequence of morphological change across many fossil specimens may in actuality represent an ugly conﬂagration of change wrought by ca- tastrophe.

The difference between these two perspectives gave rise to the opposing theories of uniformitarianism, the belief that the earth undergoes small change over long time scales, and catastrophism, of big change over short time scales. The understanding that both of these perspectives are but the outcome of the record we are left with at this moment in time is a recent revelation described previously in chapter 1.

Punctuated differences in fossil distribution and morphology represent moments of dynamic change in which the ecological basis for a stable existence were altered. Such moments can be attributed only to natural events sufﬁciently disruptive as to

21 affect population controls maintaining the stable balance of the ecosystem. These events include hurricanes, volcanic explosion, earthquakes, climate change, ice age, meteors, and the like.

Throughout the modern Age, the progressive effect of human inﬂuence in the establishment of organisms has taken over the natural stability that preceded it. Hence the rise of man’s dominance represents an event on the scale of hurricanes and ice ages as a punctuated moment of evolutionary change on the geologic scale. Obser- vations of extant species at present are immediately framed within an ecology constructed by human inﬂuence.

From this viewpoint, the author agrees with Bates (1956) in positing that “the experimental-like situations produced by man’s alteration of environmental factors, and by his movement of organisms into different environments, offer the possibilities for study that seem to me not to have been fully realized.” Much of the current research has been focused on conserving the natural stability, while failing to realize that this stability has been lost many times over in the past and that the current opportunities availed would be put to better use in understanding what kind of stable system will come from man’s inﬂuence, termed the noosphere. In these circumstances the inﬂuence of man should be of as much academic interest as the effect of natural phenomena.

Both of these like effects will be discussed in this chapter in terms of the establishment of minute land snails on distant Paciﬁc Islands both as fossils of creatures deposited by natural means, hurricanes, and as extant taxa now existing within a symbiotic relationship with man. No where are these distinct characters more articulated than on the atolls where fossils have been discovered hundreds of feet beneath the surface in depositional layers from a time when the island lay well above the water’s surface and modern taxa completely adventive and dependent on the human- induced environment as the island, once inhabited by snails, subsided to the current low elevation to the point that hurricanes completely inundated the island extirpating its endemic fauna.

Their precarious position one meter above sea level made it incredibly difﬁcult for species to naturally colonize this landform as will be described below. Thus it is only

22 through the acts of man that many of the species arrived on the atoll. This study will look speciﬁcally at land snails.

Land snails in Geologic Time: Continental vs Island species

Continental Species

Upland forests have been the preferred habitation of land snails since they ﬁrst emerged from the water 300 million years ago. At that distant time there was a marked increase in large trees that continually shed broad, thin leaves. Beneath the canopy of broadening leaves shade increased, prolonging the desiccation of the underlying leaf litter that was continually restocked by the aseasonal shedding of those leaves. Subsequent increases in leaf transpiration, the evaporation of water from the leaf to the air, further established a permanently moist environment. It is these shaded, moist conditions of permanent organic decay in which snails journeyed from the oceans and found a niche. These conditions persist in mountainous forests elevated into the cooler levels of the atmosphere where orographic rainfall, precipitation resulting from the updraft of air colliding with the mountain, maintains a permanently moist environment. Such environments provided a stable medium for land snails throughout geologic time. They have been noted as maintaining an extraordinary degree of stability in space and time compared with that of almost any other group of organisms (Solem 1981). This assessment is based on the observation that 26 of 37 land-snail families with an Eocene-or-older fossil record are still found in the same area of their initial point of appearance.

The oldest known fossils of land snails are those found in the Cumberland Group of strata in Labrador and Nova Scotia, at which point half of the ordinal groups suddenly appear within the carboniferous period (Mordan and Wade 2008). Dispersal from this original stock spread to the Rocky mountains and Western Europe when the continents lay closer together (Hausdorf and Hennig 2003). Subsequent divergence followed the widening of the continents by plate tectonics creating a natural experiment in which the contrasting characters of the two mountain ranges serves as the primary variable. The Rocky mountains are of a more gradual slope; taller, having undergone more continuous uplift, but broader throughout. It is here that the greatest stability is observed. The European mountain ranges are steeper, having undergone more extreme glaciation.

23 The steepness of the European mountains creates more isolated biotopes resem- bling island archipelagos. Many families of land snail isolated in North-western Europe were lost and those remaining exhibit a character of nestedness that corre- lates with glacial refuges (Hausdorf and Hennig 2002). Nestedness is the occurrence of restricted species within a subset of more widespread species. Ancient nu- nataks, pieces of land surrounded by frozen water, ice, or snow, acted as islands on which differential survival would foster speciation within those alpine areas. The survival of Arianta arbustorum through the last glacial maximum is a well-studied example. Fluctuations in sea-level have also created temporary islands in Crete that give rise to such nestedness (Gittenberger 2007). In these examples changes within the environment created the boundary of an island relationships by which the species was isolated and speciation could take place through vicariance. This boundary is analagous to the separation created by the divergent plate tectonics separating the original American and West European stocks.

The modern development of vicariance biogeography has been focused around these types of barriers by which speciation occurs according to geologic processes. Perhaps because it ﬁts best within the geologic perspective of time as speciation moving at the pace of plate tectonics and glaciation. According to earlier theorists dispersal is only a random variable of little effect often overlooked (Cowie ad Holland 2006). When speaking of the notoriously slow-moving land snail dispersal is apt to be overlooked. But for those studying the land snails of the Paciﬁc Islands, dispersal takes on a new character.

Minute Island Species

The island’s of the South Pacific span huge water gaps of which it is impossible for terrestrial creatures to cross under their own locomotion. To get to these islands requires one to fly or go by water. Floating across requires one to be unaffected by saltwater. Only select species of land snail are of a necessary salt resistency, such as Melamphus (Gulick 1932) and other ellobiids. For the land snail flying tends to be more productive and for this reason those species found in the South Pacific Islands have been found to be dominated by an evolutionary trend favoring several characteristics: minute size, a broad dispersal area, and large populations (Vagloygi 1975).

24 It should not be surprising that these three characteristics exist together, for they are mutually advantageous. Minute size (below 100 mm) allows for transportation through strong and violent winds over large distances, a feat incapable by larger species. For colonizing species of the Paciﬁc Islands, hurricanes and typhoons would provide the means of transportation as amongst the multitude of debris blown across the ocean would be the leaves to which these snails cling. This mode of dispersal is analagous to the seed and pollen. Land snails that are carried by hurricanes tend to be those from upland forests as hurricanes are more apt to deposit debris on a mountain.

The alternative means of dispersal is by clinging to plumage of birds. Studies have checked birds to see which land snails are found on them and have found an overwhelmingly high percentage, 95% are of the family Succineidae, characterized by a an extremely viscous mucus, with the family Vitrinae of secondary abundance (Rees 1965; Vagvolgyi 1975; Solem 1981). This method is analogous to many grass seeds that stick to the coat of animals.

The alternative between wind-dispersal and bird-dispersal for natural modes of colonization is drift whereby the species may ﬂoat upon buoyant tree matter such as coconut, pandanus, or other strand plants. Such species must be highly salt-resistant and hardy enough to be at sea for days at a time. Small size does not necessarily assist against these detriments and drift dispersed species may be found to be larger than those dispersed by wind or birds. What is required is a comfortability in water more common to those species that have only recently adapted to land out of the water and prefer to dwell in intertidal areas with modiﬁed gills for lungs. Such characteristics describe the ellobiids, a group of land snails of much less variation to the highly-speciated Styllomatophora.

Minute size has been found to be correlated to high populations and in this regard all species colonizing islands would beneﬁt, including drift-dispersed species. Labora- tory analysis has shown that high population densities are marked by lowered growth rate due to a pheromone present in snail mucus (Goodfriend 1986). These land snails thus actively avoid competition with each other creating a higher population density which provides a higher probability that a large founding population will colonize a single island.

25 By these unique abilities minute species are capable of reaching environments unexploited by larger species and proliferating quickly. It is for these reasons that 60.0% of the extant Pacific land snail fauna are of a minute size, less than 100 mm, in contrast to 27.1% of continental fauna (Vagvolgyi 1975). It has been found that following successful migration, dispersal mechanisms are often lost (Grant 1998) such as the commonality of flightless birds on distant islands. That Pacific land snails have maintained their minute size shows a continuous advantage of an ability for dispersal.

The range of a species habitat depends on two criteria: its ability to disperse and its ability to persist. Dispersal is of far greater importance to island species than it is to continental species. Islands separated by boundaries of huge water gaps supply an advantage to those limited species capable of traversing those boundaries in the lack of competition resulting from the limited number of colonizers. This process, by which “a species expands its niche to occupy an unexploited ecological opportunity” (Whittaker 1998:60) was ﬁrst labeled by Rosenzweig (1978) as competitive speciation. Continental species incapable of moving outside their niche undergo allopatric or geographical speciation (Rosenzweig 1995) whereby the geographical boundaries of that niche change due to plate tectonics forcing speciation to occur.

The unbound population of immigrant species to islands produces an evolution dominated by general traits and widespread species. The possibility of extinction within an island environment is also higher resulting in a state that island species are often do not exhibit a stable evolution, a situation that has been labeled disharmonic. Such circumstances are open to sudden changes by newly introduced migrants. This may be contrasted to the harmonic relationships of continental fauna that exhibits a closed system where species are unlikely to move out of their niche, extinction levels remain low, and few sudden changes occur. Within the harmonic situation of continental species it is plate tectonics and other large-scale phenomenon seen on the geologic scale of fossils that have the greatest impact. Vicariance biogeography has therefore focused on fossil evidence. However, the disharmonic situation of island species are more greatly effected by storms that occur on a shorter time scale. Therefore large changes may be seen within soil deposited over the course of only a few hundred years, a scenario more important to this study.

26 Land Snails of the Paciﬁc

Within the same deep drilling that proved Darwin’s subsidence theory, Ladd (1958, 1968) reported the discovery of fossil specimens of four species of minute endodont land snail on Bikini, Eniwetok, and Funafuti Atolls, islands separated by massive water gaps across the Paciﬁc Ocean. Later, Solem (1977) reported endodontid land snails from Midway Atolls of two additional species. These fossils were found at depths ranging across four different geological time periods (see Table 2-1).

Table 2-1: Fossilized Land Snails found in the Marshall Islands

period depth(ft) island species (Ptychodon)

Lower Miocene 1807-1818 Bikini (1 partial) Ptychodon subpaciﬁcus

Upper Miocene 820-831 Eniwetok (1) Ptychodon Eniwetokensis

Early Pleisto- 447-453 Bikini (7) Ptychodon inexpectans cene

Late Pleistocene 166-170 Funafuti (1) Ptychodon species A (P. nuda)

Late Pleistocene 35-50 Midway Cookeconcha antiquus; Protoendodonta laddi

The Endodontid family of land snails are widely distributed throughout the high islands of Polynesia and Australasia today where they are found in forests similar to that favored by most species of continental snails. That they occur on these atolls has been cited as proof that those islands were once well above sea level as raised coral atolls despite the fact that they currently lie only a few meters above sea level. A deposit of limestone marked by recrystalization and leaching within the geologic cores attest to the exposure of that layer to the air and hence emergence (Ladd 1973) that may likely be associated with a sudden drop of sea level that would have left the island well above water. For the snails to survive it would also be necessary that the islands to be forested. Such a forest was described by Leopold (1969) which could have colonized the islands by the same winds as the land snails. That these land snails occur at several distinct points throughout the geologic history would appear to indicate a stable existence similar to the natural history of continental land snails based on an ability to continually re-colonize the same islands whenever conditions allowed.

27 It was noted that no such land snails were living there at present, to prove against contamination from the surface; additionally, all specimens appeared to be true fossilized with those dated to the Miocene exhibiting a characteristic coloration. The recent submergence of the island would have killed any land snails living on the island and none had colonized the low-lying atoll in the short period since it had re- emerged. As upland species hurricanes are their theoretical mode of their transport. Low-lying atolls are commonly inundated by the raised storm swell that accompanies hurricanes and typhoons. Personal reports of a recent hurricane in Tokelau provide an anecdotal account conﬁrming the inundation, matching reports in the literature for the effects of typhoons in the Marshall Islands (Blumenstock 1961) and anomalous high-tides in Tuvalu (Yamano et al 2007). For snails whose mode of transport is dependent on hurricanes, atolls can then be deemed uninhabitable. Bands of limestone exhibiting exposure and inundation within the geologic cores exhibit the repeated cyclical events of submergence and emergence of the island. Each of the samples appears at the middle of the period of exposure. Thus the fossil record in actuality shows the repeated colonization of the island through a reliable dispersal ability beyond mere chance.

Endodontidae and three other endemic pulmonate families, Achatinellidae, Amastri- dae, and Partulidae, make up “a major part of the immense native land snail diversity of the islands of the Pacific” (Cowie 1996:347). Achatinellidae and Amastridae are both tree-dwelling snails endemic to Hawaii where the greatest diversity of species of land snails is to be found with over 750 species. The phenomenally high endemic speciation may be attributed to the movement of the Pacific lithospheric plate that has created the Hawaii-Emperor Chain over the course of 70 my composed of at least 60 known islands and former-island sea mounts (Rotondo et al 1981). This natural history allows for a multitude of founder populations to provide the impetus for speciation. Partulidae and Endodontidae are similar species found the Pacific Is- lands other than Hawaii and follows a similar history. All of these are part of the sub- order Orthurethra and share a unique ability of natural dispersal that led early theorists to speculate on an ancient Mid-Pacific continent (Pilsbry 1900, 1916).

Sea-level changes would likely play a role in the speciation of this widely dispersed Order. As has been shown by the cores into the atolls anemochoric species, those that disperse by wind or storm, could colonize the raised atoll island on a cyclical ba-

28 sis. Successive colonizations of the islands over a period of 40 million years would allow for those islands to act as stepping stone islands on the same cycle adding an extra variable to speciation.

Pilsbry (1916) divided land snails of the Paciﬁc into two categories: those that favor high island forests and those that favor low-lying coasts. The endemic fauna, including those families described above, are conﬁned to the interior and typically mountainous regions of the high islands, supporting a belief in a long natural history of hurricane-blown colonization. The second of the groups that colonize the low-lying coasts and atolls exhibit a widespread, general character typical of a recent fauna with exceptionally high dispersal rates (Cooke 1928; Peake 1969).

This group of land snails would seem to favor a different mode of transportation. Coastal life tends to arrive by water and be salt-resistant. As such species don’t appear in the ancient record and are mostly noted in modern and historical surveys it is worth hypothesizing that their mode of transportation is of relatively recent derivation. Living in the modern Age it is plausible that humans should be the introducing variable. The test for such a hypothesis lies in the atoll an island form that is limited to a low-lying coast. Indeed early malacologists noted a common “atoll fauna” which were seen to be dispersed by Polynesians in their migrations (Cooke 1928; Reigle 1964; Harry 1966).

Cooke (1928) noted four waves of land snail colonization. The ﬁrst wave provided the major endemics Partulidae, Achatinellidae, and Amastridae and can be placed at the Oligocene. The second and third provided Endodontidae, and some of the other well known families such as Succineidae, which travels by birds dating to the Miocene-Pleistocene. The fourth wave represents those land snails carried by people. Cooke writes...

These for the most part are minute species of snails that are always found in situations just above high-water mark and are fairly uniformly distributed wherever Polynesians live. Such shells have but one habitat, living on the low ﬂats in a belt between high-water mark up to a few hundred feet elevation. They are abundant in the native villages and in the plantations, being found usually on or under dead coconut leaves and coconut husks. A very small number are found on the leaves of plants, especially the banana in

29 cultivated plantations. These are the only species that are known to occur on the low coral islands and atolls. (1928:2279)

This particular fauna was likely carried by the Polynesians accidentally while moving along with the plants of which leaves the snails feed upon. As atolls are repeatedly inundated by hurricanes (Blumenstock 1961) and are susceptible to ﬂooding by anomalous high-tide levels (Yamano et al 2007) snails not resistant to salt-water would die off quickly unless continually re-introduced. Likewise, residents of these islands must continually rebuild their gardens providing the means for this re- introduction. Deposits should therefore show such re-introductions.

This is not to say that land snails have only been transported by accident. Recently, Taehwan et al (2009) reported on the discovery of a prehistoric trade in white-shelled snails of Partula hyalina, from Tahitit to the surrounding islands. Its status as an endemic with a multitude of species marked by different coloration allowed the study based on DNA haplotypes to trace the descent of different voyages carrying the snail. The use of the shells in lei necklaces and the selective preference for white shells provided the motivation for purposeful importation of the snails. However this example is unique.

The atoll fauna is composed of minute shells of no explicit purpose and therefore may be assumed to have been introduced accidentally. The low diversity and widespread nature of these snails have been denigrated by biologists concerned with speciation as only a minimal data-set. They have been called tramp species. How- ever, for the archaeologist all of these snail specimens represent artifacts of the settlement of the island.

Studies of Ulithi atoll by Harry (1966) postulated that most if not all of the species were disseminated by man. The fauna was noted as being richer than most atolls, a fact that was attributed to the tradition of annual commerce ﬁrst described by Chris- tian in 1899. The effect of man has therefore been realized in the species diversity of atolls.

30 Summary

Land snails dependent on hurricanes as their means of dispersal are found to be limited to islands that contain upland forests. Fossilized land snail specimens on atolls attest to the ability of hurricane-dispersed species to colonize these islands when they were well above sea level. At their current low level, however, hurricanes regularly inundate the entire land area with saltwater making it uninhabitable to colonizers. Thus low-lying islands such as atolls would be incapable of supporting landsnails dependent on dispersal by hurricanes because the means of dispersal is also the cause of their habitat destruction. Instead one would expect salt-resistant drift- dispersed species which prefer strand environments to be highly favored. This con- dition may be easily tested by sampling deposits on atolls prior to human habitation. If landsnails dependent on hurricane dispersal, such as those of the family Pupillacea (partulidae), which cling to the underside of dead and living leaves (Solem 1981), are found then this theory would be disproven. If drift-dispersed species such as Trun- catella and other ellobiids are found then this would provide supporting evidence.

Modern land snails have found a new ability to disperse through man. Man’s colonization of small atolls required that the environment be changed to make habitation possible. Agricultural development created a more lush humic layer for land snails to feed on and a shadier area around homes. Man’s importation of food plants carried with it land snails clinging to the soils around these plants. Thus the settlement of island’s may be directly correlated with the appearance of land snails associated with agricultural activities, such as Gastrocoptus Pediculus, Lamellidea oblonga, Pupi- soma orcula, and Allopeas gracile (Kirch 1973; Christensen & Kirch 1981; Rolett 1992; Preece 1998), that have developed symbiotic relationships to the environment’s that human’s create. Introductions of new species into the record would represent settlement between different islands and the development of new habitations and agriculture. Such introductions may be easily tested by sampling the land snail fauna found in archaeological contexts.

31 Chapter 3: The Beginning of Atoll Archaeology

The first archaeological investigations made on atolls were performed by Emory (1933, 1934a, 1934b, 1939) and focused on the stone marae that survived on the surface of the islands and the material culture as it existed at the present time. These publications represent a valuable record of prehistoric monumental architec- ture that been greatly affected in the time since Emory first saw them. However, few attempts at subsurface investigation were made until the 1970s. Even then excavation tended to focus around surface finds (Sinoto and McCoy 1974). This chapter will focus instead on the development of a systematic method of subsurface investigation for atoll archaeology and the discovery that intact layers do exist on these low-lying islands. Though some projects found it difficult to find significant deposits (Fujimura and Alkire 1984; Takayama et al 1990) the overall potential of atoll archaeology is en- ticing and sorely under-investigated.

Nukuoro Atoll, Eastern Caroline Islands

In the late 1960s, Janet Davidson, led the first major archaeological investigation of an atoll with the express purpose of addressing doubts whether atolls “offered any worthwhile prospects for excavation” (1971:2). Nukuoro was chosen based on linguistic evidence cited by Pawley (1966) that the people spoke a Polynesian language and on the presence of Polynesian-type one-piece fishhooks made of pearl shell, that defined Nukuoro as the most distant Polynesian outlier to the North. Davidson states, “the steady accumulation of archaeological data from both East and West Polynesia was prompting the formulation of new questions about Polynesian prehistory, and arousing interest in the hitherto neglected outliers” (1971:2). The major ob- jectives were to define the length of recognizable Polynesian occupation and the possible presence of an earlier Micronesian occupation. Emphasis would thereby be placed on locating the earliest layers and changes in inter-island contact.

Work began with a surface survey. Structural remains were found to be rare and the few abandoned house platforms were determined to be very recent as were several low coral paths. Retaining walls of coral blocks along the shore were a ubiquitous feature important to the prevention of erosion, which had been maintained throughout

32 time. The most interesting structural feature were decayed walls on the reef side of many of the smaller islets beyond the extent of the small landmass encrusted in the exposed reef and fused together. These are the oldest surface features exhibiting the forces of erosion and the antiquity of concerns for their effects.

“The most important evidence,” Davidson states, “is the variation of the ground itself. On Nukuoro there is considerable fluctuation of the ground surface which invariably reflects human activity.” (1971:4) Excavation found formerly identified ‘alluvial deposits’ to be stratified midden deposits. “Whereas high ground represent places that have been consistently occupied over long periods of time, depressions and low ground are also important as indication of former wells or small taro patches.” This is not to suggest that progradation does not exist as well as excavation would find that the ocean-side shore had moved considerably further to sea over time. Neverthe- less, an accurate survey of the slight contours and changes in elevation across the island was found to be a valuable tool that has been utilized in most subsequent studies of atolls.

Excavation focused initially on ethnohistorically documented areas based on the records made by Kubary of his visits in 1873 and 1877, and secondly on investigating a transect of the island’s depositional history. Those areas chosen based on ethnohistorical data looked at the locations of a traditional men’s house (hada), a godhouse, and a whale cult. Both the godhouse and whale cult ritual site failed to provide any artifacts that could be associated with such activities, either because such activities are not archaeologically recognizable or the reports are not trustworthy. The location of the men’s house did however provide the most abundant concentration of artifacts to be found and the land where the colonizing ancestor’s house traditionally stood provided the most deeply stratiﬁed levels. It would seem that the location of traditional houses is stable and local reports on their location are trustworthy. Excavation was made in 2 x 2 meter squares in arbitrary 15 cm levels except where stratigraphy could be clearly discerned. Forty square meters was excavated in total and though in 1971 this was seen as a “very small sample of the total archaeological deposit” (1971:27) it was possible to sample across the extent of the island and obtain a large enough sample of adzes and ﬁshhooks to form a basic typology of the island. David- son states that the results demonstrates the unique potential of small atolls to carry out so comprehensive a study in so short a time (1971:103).

33 The most beneﬁcial proxy for deeply stratiﬁed deposits was the elevation above sea level with raised areas repeatedly providing abundant material. These areas, however, did not necessarily promise to contain the oldest deposits as the original paleosurface was found to run fairly level across the island. The oldest habitation layers were found instead to be located on the lagoon side of the original paleosurface. It seems probable that early habitation sites of most islands will be found in the same location as this is the most logical area being protected form the sea swell and close to the resource-abundant lagoon.

The smaller islets were found to have minimal deposition and to be of little archaeological interest to the main village island which had undergone signiﬁcantly greater deposition over a lengthy period of habitation. Habitation appears to have always been conﬁned to the current village island. Nevertheless the oldest trusted dates could only be placed at 1600 AD with the deepest layers below being estimated at 1500 AD, despite digging up to 270 cm at some locations to very close to the water table. Whether these deposits represent the earliest occupation or earlier layers lie below the water table or were washed away by hurricanes is unknown. Nukuoro is unique in being relatively free of hurricane activity and geomorphological change seems a more likely cause for erasing older layers. Davidson makes the point that progradation of the island would have altered the shape of the water lens and raised it above its older level.

The most reliable proxy for relative dating were found to be the presence of dog bones in the older layers, pearl shell coconut graters in the more recent layers, and the ﬁshhook assemblage. Such indicators were of great value in relating the layers of distinct areas to each other and thus understanding the overall depositional history of the island. Beyond these changes the material culture was found to be relatively stable throughout the excavated occupation with an already well-adapted culture at the lowest layers. That such a stable culture dominates the assemblage from the beginning further suggests that the oldest layers are not present. Further linguistic study has found the Nukuoro language to be a Polynesian dialect far removed, requiring a ‘fairly long development in isolation’ (1971:104) well beyond the four hundred year history exhibited. Further, Davidson found the material culture to be similar enough to that of the Micronesians to be indiscernible. As this was the earliest such study, a complete analysis would have to wait until other surrounding islands and

34 those atolls closer to Polynesia had been investigated, which brings us to the next research project.

Ulithi Atoll, Western Caroline Islands

Response to Davidson’s discovery of intact subsurface midden deposits on Nukuoro was met with stubborn refusal to believe that such ﬁndings represented any more than an “unusual archaeological phenomenon for an atoll environment” (Bellwood 1979:293 cited in Craib 1980:52) due to its geographical position outside the typhoon belt. Craib’s subsequent study of Ulithi Atoll far to the west well into Micronesia thereby gave an opportunity to seek additional subsurface deposits on an island within the typhoon belt and provide artifacts for a comparison of the material culture.

Ulithi Atoll is quite large relative to atolls and is much larger than Nukuoro, with a considerable historic European presence providing a wealth of ethnographic reports and a significant amount of disturbance to islets occupied during World War II opera- tions. A research methodology was therefore devised quite different from that on Nukuoro that better fit to the large island size. A surface survey was undertaken with the goal set of complete coverage, though the dense vegetation of uninhabited islands made this difficult, an obstacle that would become common in atoll archaeology. The majority of findings consisted of concrete foundations from military instal- lations, Ulithian house platforms of coral alignments, graves lined in coral or coke bottles, and scatters of Yapese laminated pottery sherds. The most intriguing finds were coral uprights associated with the meeting of chiefs from throughout the neighboring islands (Craib 1980:88).

All of these finds conform to ethnohistorical reports, the most useful of which being a 1904 census performed by Arno Sefft, a German District Officer stationed in Yap that made three separate visits. In 1907 a typhoon hit Ulithi so that a comparison of the location of villages reported in the census and the surface finds made by Craib serves as a useful measure of the destructive forces of a typhoon. The close association of these two records shows storm activity to be far less destructive to surface features than initially assumed. In contrast, Craib’s assessment was that the growth of local vegetation was far more destructive (1980:187). Additionally, cultural factors were found to have a large impact, such as the military presence which completely altered the landscape of several islands and the recycling of building materials from

35 old sites by locals. Though local informants could easily direct the researchers, with confidence, to areas where ancient men’s houses once stood, there was no evidence of the prehistoric structure. Thus the surface finds are most likely all of historic age and Craib’s following statement, though specific to a single islet equally applies to the others: “With this more recent use of the islet it is not known how well the present configuration of features reflects the pattern of settlement prior to its prehistoric abandonment” (1980:167).

Subsurface testing was limited to small shovel hole tests that measured 50 x 50 cm to one meter in depth to assess the presence of subsurface deposits in the areas where surface ﬁnds were made and to demarcate the limits of such deposits if they should exist (American style). In addition pits made by modern activities including the digging of a septic tank and a grave provided the most complete observation of subsurface levels. No attempt was made at a complete sampling of these deposits, rather, only an effort to assess the presence or absence. The majority of sites in fact contained subsurface midden though the depth was sometimes limited to only half a meter for some sites and sometimes reached below the extent of the one meter excavation for others, offering some idea of the length of occupation (Craib 1980:84).

In all, the subsurface testing appears extremely useful in assessing where the best locations would be for more in-depth excavation to occur and is a proper method for phase I investigations. This is especially true since the layers were found to be often discontinuous and full survey would be needed to assess where the best preserved layers were located. The discontinuous, disturbed nature of the deposits makes cor- relating layers between separate areas a unique challenge for which simple trenching does not necessarily promise an answer. Topographical variation was found to be of less use than on Nukuoro perhaps because of the lengthy period of military disturbance or the large size of the island.

The adze collection discovered by this project is diverse and looks very similar to that found on Nukuoro with Tridacna as the primary material and Terebra, Conus, and Cassis being used additionally. A variety of forms were noted with straight and rounded bevels, and of both quadrangular and plano-convex. Fishhooks were rare as ethnohistoric reports document their construction being of wood and therefore of poor preservation. Nukuoro differs in its use of pearl-shell though this could be ex-

36 plained by a lack of raw material on Ulithi. The most signiﬁcant difference though is the ubiquitous presence of pottery at Ulithi as part of the Sawei trade/tribute system whereby resources were moved between high and low islands in a parent-child relationship. Hence pottery appears as a categorically Micronesian artifact with pearl shell ﬁshhooks being characteristically Polynesian.

Thus the present study of Ulithi effectively debunked the notion that atolls within the typhoon belt would not contain subsurface deposits by both exhibiting the presence of such deposits and showing the minimal effect the typhoon of 1907 had on surface features. Settlement was found to favor the lee side of the islets as opposed to the lagoon side, however those islands with their lee on the lagoon side were favored above all and the sample seems biased by the large number of islets that were inhabited at present. Only one date was obtained and this was so extremely old that it was not trusted. As little subsurface sampling was performed it is found to be of little informative value.

Kapingamarangi Atoll, Eastern Caroline Islands

Between 1979 and 1980, Foss Leach and Graeme Ward of the University of Otago spent one month performing fieldwork on the atoll of Kapingamarangi, the first island encountered south of Nukuoro. Like Nukuoro it was seen as a Polynesian outlier based on the language spoken by the locals at present. The extreme isolation of Kapingamarangi was a well-noted characteristic due to the unpredictable nature of the surrounding sea marked by currents that fluctuate seasonally. However, in relation to Polynesia Nukuoro is the more isolated though it lay closer to Micronesia. Drifting logs from the large islands east of Papua New Guinea to the south was however such a common occurrence that it was seen as the primary explanation for the presence of volcanic material on beaches which would have drifted within the roots of such driftwood. The alternative is that the material was purposefully imported and had since eroded onto the beaches. At the time of the study a flourishing exchange network was noted whereby volcanic cooking stones were imported on every ship. In either case the isolation of Kapingamarangi for skilled navigators is a matter of debate. Traditional knowledge of the island’s location by people of surrounding islands including Lukunor (Mortlock islands), Nukuoro, Ontong Java, and the told arrival of

37 three to eight canoes from Marshall islands are evidence against extreme isolation (Craib 1981:2).

The surface survey found that the presence of culturally modified surfaces was the most common evidence of cultural activity on the surface with only a few remnants of structures and walls present. These surface artifacts were of little archaeological value. All but one island were devoid of significant deposition. The cleanliness of the island’s occupants at present which was assumed to be characteristic of the people throughout the entire occupation was cited as the cause of such minimal deposition. Storm activity and erosion, however, seem to be more likely causes. The only islet of considerable deposition was Touhou islet which was noted to have 70 buildings on it in 1942 according to an American Intelligence report (Craib 1981:23). In contrast to the other islets which stood only one meter above sea level, Touhou islet was found to have four meters of deposition. Subsequent excavations would find the entirety of this deposition to be cultural.

Subsurface testing followed the example of Davidson by excavating a transect of 2 x 2 meter units across the center of the islet (New Zealand style). Due to time limits and the extreme depth of the deposition only four units were excavated though this totaled 54 cubic meters. The determination of the layers was found to be problematic due to the amount of banding and concentration of coral lenses. Excavation followed arbitrary 20 cm spits and proﬁles (cross-sections) were made according to clear changes in the soil matrix. This is would become a recurring difﬁculty of excavation on atolls, noted by Davidson as well. The location of test units were chosen based both on elevation above sea level, ethnographic reports, and surface evidence.

The location of the ﬁrst unit was chosen at the highest point of the island and was reported by one of the oldest men to have been a trash dump, which differs from the current activities of people who throw their rubbish in the sea. Coral uprights were also noted on the surface. Excavation went down 4.6 meters at which point the water table was encountered. The upper 2.5 meters of deposition was found to have occurred within less than 250 years with a large wet area postulated as a possible evidence of dryland taro cultivation. Below this rapid deposition paleosoils were dated at 679 BP exhibiting a break in the depositional history (Leach and Ward 1981:37).

38 The location of the second unit was chosen at the lagoon shore next to the current men’s house. This area was found to be relatively recent compared to the other units based on coins dated to 1927 or before found to layer 3 and dates less than 250 years old in the lower layers. It only went a couple meters suggesting it has formed due to natural progradation of the island.

The location of the third unit was chosen based on ethnohistoric reports of a burial house and the presence of cooking debris (charcoal and midden) at the surface. Evidence of cooking extended only into layer 3 dated to 257 BP. Below this the dates jump to 535 BP and deposition changes to a more natural looking deposit associated with the artificial buildup of the island. Cultural deposits lying directly on the underlying coral basement show that the island was occupied even when it was nothing more than a barren paleoreef. Dates could not be obtained for this most ancient occupation due to its continued inundation. Nevertheless occupation directly on top of the coral bedrock and the artificial buildup of the island are the most intriguing finds of the project.

The location of the fourth unit was chosen in the center of the island where ethnographic reports place the greatest concentration of buildings including a cult house. Though deposition was not the deepest it provided the greatest wealth of artifacts including one-piece fishhooks, coconut grater heads, shell arm rings, and adze fragments. In addition, layer 3 was dated to 354 BP a time period not seen in the other units. The fishhooks are a particularly important find relating to the antiquity of Poly- nesian affinities dating back to 350-550 uncalibrated BP (Leach and Ward 1981:53) with lure shank hooks found in previous units dated to the latter end of this range.

The project is to be commended on its radiocarbon dating which was the most complete for an atoll to date. Gaps in the dates of deposition and the belief that a separate islet had to be occupied during the initial occupation of Touhou’s coral basement suggest that a complete view of Kapingamarangi’s prehistory is impossible given the lack of deposition on the other islets. This is a circumstance that must be accepted and is the ﬁrst evidence supporting the initial claims for limited deposition. It is most troubling in denying a look at the earliest settlement leaving theories on the origins of the founding people to proto-linguistic postulations. However, the presence of four and a half meters of cultural deposition clearly shows deposition does occur, and

39 such deposition is purposefully done by the island’s occupants to create an artiﬁcial island to both protect the islet from geomorphologic forces and to increase the freshwater lens.

An additional conclusion to be drawn from this project is that one should not necessarily assume that practices and events at present have continued throughout prehistory. Though people at the time of the study disposed of the rubbish in the sea the presence of subsurface midden deposits show that this was not always the case. In contrast, the fact that the importation of volcanic cooking stones is such a common undertaking at present should suggest that it might have been performed in the past as well, though, as just stated, it can’t be assumed. Yet, several differences between the material culture of Kapingamarangi and Nukuoro point to their isolation: dog is present in prehistoric contexts on Nukuoro but not on Kapingamarangi, different species of rat are seen on the two islands, and a much more varied typology of adzes was exhibited on Nukuoro which cannot be attributed to a lack of raw material on Kapingamarangi. A more varied ﬁshhook assemblage also existed on Nukuoro but this may be attributed to differences in raw material.

Kwajalein Atoll, Marshall Islands

In 1987, archaeological testing and monitoring was undertaken by International Ar- chaeological Research Institute Inc. (IARII) on the largest atoll in the Marshall islands, the Paciﬁc, and the world, Kwajalein atoll. The project was made in accor- dance with construction activities involved in the renovation of the military airﬁeld runway which, under American law, requires an archaeological investigation as part of the conservation measures for all public works (Beardsley 1994:1). The runway covered at least half the area of the main islet, appropriately named Kwajalein islet, and therefore offered a clear sampling of the spatial distribution of potential archaeological materials across the length of the islet.

Preservation was an immediate concern. While previous projects, mentioned above, had done well to prove the existence of subsurface deposits on atolls even within the typhoon belt, Kwajalein’s history documented extensive alteration to the ground surface. On the 31st of January 1944, D-Day, a massive air assault was waged on the island as the initial maneuvers of Operation Flintlock in which the Americans intended to take the island from the Japanese.

40 “An estimated 100 pounds of bombs and shells fell on each square foot of Kwajalein Islet, ﬂattening the vegetation, shattering structures and creating what has been described as a nightmare of noise. So much ordnance was dropped onto this tiny islet that some believed it would sink before the invasion even started.” (Bell Telephone Laboratories 1974 cited in Beardsley 1994:16)

Hence Kwajalein Islet had underwent the most extensive disturbance one could imagine, save perhaps for Bikini Atoll where nuclear testing had actually destroyed small islets and portions of larger ones. The prospect of locating subsurface deposits offered proof of the indelible value of atoll archaeology no matter the level of disturbance. In fact, not only were subsurface deposits located on Kwajalein Islet, but they were also found on Bikini Atoll (Streck 1990).

Field methods focused upon backhoe trenches that were made to expose the underlying stratigraphy. Short sections of these trenches excavated with pick and shovel to expose a clean proﬁle were labeled stratigraphic pits. One by one meter grid units excavated by trowel into these stratigraphic pits should signiﬁcant cultural deposits be observed. In this way the project was able to cover the entirety of the effected area while focusing on those areas of greatest value. Monitoring of construction activities and surface surveillance was made with less results. The resulting excavations were grouped in nine different areas numbered from west to east.

Areas I-III (Beardsley 1994:35-48) were composed primarily of historic fill associated with the construction of the World War II military base on top of a natural beach deposit. Moving eastward the natural deposit changes from a coarse, granular marine- derived sand to a very fine aeolian sand to a thin dark A horizon in Area III. These profiles show that the western third of the runway occupies an area that was characterized by unconsolidated sand bars and little organic development prior to historic contact.

Areas IV-VI (Beardsley 1994:48-66) revealed two prehistoric cultural layers. The upper cultural layer was the more complex exhibiting multiple events within a continuous occupation marked in places by a coral gravel pavement. The lower cultural layer was composed of a unique gray clayey lens not formerly reported in the Mar- shall Islands that was interpreted as the possible remnant of a natural or culturally- modiﬁed swamp. These layers were ﬁrst revealed in Area IV as continuous deposits,

41 became more complex in Area V and in Area VI the upper layer became more disturbed. These areas contained the greatest quantities of artifacts.

Areas VII-IX (Beardsley 1994:66-94) show a continuance of the same depositional layers as Areas IV-VI but with increased disturbance to the upper layer and more substantial preservation of the lower. It is here that the greatest information on the earliest cultural episodes is to be found with two radiocarbon samples, one from the grey clayey layer of the former swamp and the other from a hearth, dating to 2000 BP providing sound evidence of the earliest colonization of an atoll. A single pollen grain of Artocarpus found in this former swamp attests to the early introduction of this valuable food source at the beginning of settlement (Horrocks and Weisler 2006; formerly identiﬁed as Colocasia in Beardsley 1994:85). It is in only these layers that turtle bone is found and the most secure deposits of dog bone. Unfortunately, however, two of the grid units that promised the most valuable cultural materials were destroyed by construction activities before they could be fully investigated.

The results of the project therefore showed a progradation of the islet’s western side with the earliest settlement occurring at the middle of the islet. A date of 1000 BP from an earth oven within an extension of the upper coral paving provided by Area IX gave the earlier parameter for the upper deposition with a date of 300 BP in Area IV providing the later. Most important though is the presence of Colocasia and a culturally modiﬁed taro swamp at the earliest episodes 2000 years ago showing the purposeful modiﬁcation of the atoll environment and introduction of food plants at the time of initial settlement. This evidence suggests that the colonization of Kwajalein was not made accidentally by random drift, but by purposeful voyaging and habitat construction.

Equally important is the discovery of intact subsurface deposits despite the most heavily altered island surface imaginable. Like previous atolls it was assumed that no intact deposits would be present and previous studies (Craib 1989) emphasized the futility of such measures. Even at present Kwajalein is still described as such a heavily impacted landmass that research is discouraged (KRS personal communication). This project should effectively end the argument on the existence of subsurface deposits. While geomorphological forces and cultural modiﬁcation will likely

42 lead to some level of disturbance, the presence of valuable archaeological material is always possible and worthy of investigation.

Summary

These projects represent some of the ﬁrst attempts at systematic subsurface excavation on atolls. Other such projects will be mentioned in the following chapter as well. From the projects discussed so far several conclusions can be made.

1) In most all examples limited data was found on the surface and was primarily of an historic derivation. The most valuable data on the surface was the slight contours in the topography that could represent accumulations of cultural material below the surface.

2) Cultural deposits were concentrated on the largest islets that had remained inhabited throughout the island’s settlement with little prospects for ﬁndings on the smaller, outer islets. Because of the consistency of the settlement, however, major structures had remained in the same location throughout time and local informants could often be trusted to remember where former buildings once stood if no longer standing. Storms were not found to have a major effect on these inhabited islets most likely because the inhabitants re-developed the village soon after and actively raised the surface.

3) The common sedimentary history of the atolls placed the oldest settlement on the lagoon-side of the interior where the old beach would have existed prior to later progradation. Island development then occurs horizontally so that different dates may be obtained in different areas even if dug to the same level. Due to these circumstances a transect of test pits is most appropriate for assessing the subsurface deposition.

4) Sedimentary layers are often complex and difﬁcult to interpret with artifact assemblages providing a greater value for relative dating than superposition alone. The present study will build off this ﬁnal assessment by proposing that the introduced land snail fauna, an artifact assemblage in its own right, may be used for relative dating purposes to compare distinct areas of excavation.

43 Ch. 4 The Vegetative History of Atolls: Marshall Islands case study

“It was quickly obvious to them that the high degree of manipulation of the vegetation by man obscured the natural vegetation succession and that it was very difﬁcult to interpret the natural ecology and environment from the apparent patterns.” (Wiens 1956:25)

Leach and Ward (1981) were the first to draw attention within archaeology to the dif- ficulties of understanding the pre-European vegetation based on the studies described above. Their only sure assumption was that there is a striking difference between the natural flora that was able to colonize the island previous to man and that seen today. Nevertheless the discovery of ‘man-made island’ no doubt effected the diversity of plants capable of living on that island by increasing the freshwater lens and providing protection from groundwater salinity.

In 1954 the Paciﬁc Science Board Expedition made a thorough survey of Kapinga- marangi including the vegetation. Of 98 vascular plants observed 38 were classiﬁed as indigenous and 58 as introduced, with 16 of those labeled as introduced believed to be Polynesian introductions (Niering 1956:4). On Arno Atoll in the Marshall Is- lands, Hatheway (1953:3) reported that of 125 vascular plants nearly half (57) had been introduced in the past 100 years, 38 intentionally and 19 accidentally. Of the 68 remaining species 24 were believed to be introduced by the Marshallese. Thus, a common pattern is seen whereby the larger percentage of plants found on atolls are introduced.

Zones of Vegetation and Soil Development

Niering (1956) placed the vegetation into four zones moving from the shore to the center of the island. This practice followed the observation of definite vegetational zonation first made by Fosberg (1949). The outermost, shoreline zone was found to be dominated by strand-line scrub, specifically Scaevola frutescens on the oceanside and Suriana maritima on the sandier lagoon side, with Cordia subcordata and Soulema amara on the inner edge providing a broadleaf, salt-resistant forest that provides protection to the inner zones (Spennemann 2006). Inland from this initial

44 zone was an area of mixed Pandanus and coconut (Cocos nucifera). While both of these plants are capable of natural drift dispersal it is largely accepted that there pro- liferation on atolls is due to introduction by man evidenced by the large number of distinct types. Further inland is a zone of a more mesophytic type of forest, often dominated by breadfruit where it has been introduced or Pisonia grandis where it has not, forming a dense canopy with sparse undergrowth. At the center of the islet are found the pulaka pits (Cyrtosperma, or swamp taro) planted at the area with the largest freshwater lens. The dominant vegetation within these zones (coconut, pandanus, breadfruit, pulaka) are all recognized as early introductions and are important food sources. The more recent introductions are primarily ornamentals and com- promise many species but are of lesser abundance. The bulk of the native vegetation occurs in the strand-line and understory and are used for ﬁrewood and construction materials.

The progression of these zones inland is related to increases in the freshwater lens and protection from salinity in the form of salt-spray and ground water salinity. The groundwater of an atoll is marked by the Ghyben-Herzberg lens of freshwater that sits on top of the saltwater due to its difference in solubility, 40:41. The depth and salinity of this lens depends on its distance from the beach and the permeability of the soils (Hatheway 1953:4). Hence the stony coral boulders and coarse sand grains that dominate the oceanside allow greater salt inundation than the ﬁne sandy soils of the lagoonside with the center being most protected. Salinity is a major control in the distribution of breadfruit (Fosberg 1949) as well as other non-strand species as discussed in greater detail below.

A most valuable discovery of Niering’s study was the positive correlation of ﬂora diversity with islet size. The islets surveyed were divided between three classes: smaller (3.5 acres or less), intermediate (3.5-9.5 acres), and larger (over 9.5 acres). The smaller islets were dominated by the ﬁrst zone of pure coconuts. The intermediate islets contained zones one and two of coconut and mixed coconut-breadfruit at their center. The larger islets contained all four zones.

Whitehead and Jones (1969) reported similar ﬁnding, describing in greater detail the anomalous circumstances on exceptionally small islands, smaller than 3.5 acres, that resulted in atypically low levels of species diversity. Islands of this tiny size are not

45 large enough to produce an interior freshwater reservoir which, according to Wiens (1962), typically develops only within areas 175 feet or more from the shoreline. The ﬁndings of Arnow (1954) substantiate this fact by documenting a marked increase in sodium and chloride levels in groundwater within 175 feet of the shore on the North- ern Marshall Islands and 250 feet in highly permeable soils such as those found on the oceanside of an atoll. A perfectly circular island with a diameter of 425 meters, the combined measurement of these two parameters, would have an area of 3.24 acres, thereby making 3.5 a realistic ﬁgure.

Below 3.5 acres the island is composed of one environment type, that being a strand environment which only salt-tolerant, typically drift-dispersed species may colonize. The only non-strand species present were found to be dependent on strand species such, as Asplenium nidus, a fern that grows in broken coconut hulls (Whitehead and Jones 1969). It is only on islands above 3.5 acres that non-strand, salt-intolerant species may propagate. These species may be wind and bird dispersed but are typically far more likely to be composed of introduced species.

The small size of most Paciﬁc atolls, means that they straddle the threshold between these two island types. They arise out of the ocean, salt-laden and tiny. Only after they have arisen far enough out of the water to have grown of a large enough size could the salt be washed away. Their extreme isolation means that wind- and bird- disseminated species are rare compared to the more common presence of drift dispersed species. Thus strand-line species quickly populate the tiny atolls early on while non-strand species understandably have much greater difﬁculty.

According to the equilibrium theory of island biogeography (Whittaker 1998) ﬁrst developed by MacArthur and Wilson (1963), every island has an equilibrium number of species determined by the immigration rate and the extinction rate. The high immigration rate of drift dispersed species allows for the total potential diversity of strand species to be achieved very quickly. Islands of small size are also greatly affected by storm activity leading to a inordinately high extinction levels and a state of overall in- stability. This circumstance means that the low immigration rate of wind- and bird- dispersed species leads to exceptionally low level of diversity. Ultimately, area size has little effect on the diversity of strand-line species which increase in numbers line- arly increasingly with island size. In contrast, area size has a large effect on the di-

46 versity of non-strand species which increase exponentially with island size once the 3.5 acre threshold is crossed to allow for a large enough freshwater lens and moderate protection from storms (Whitehead and Jones 1969).

Because, as stated, the immigration of wind- and bird-dispersed non-strand species is relatively infrequent non-strand species disseminated by people which have a much higher rate of immigration establish very easily without competition. Therefore non-strand environments are largely dominated by species accidentally or purposefully introduced by man. This is different to the strand environment which is easily dominated by drift-dispersed species.

On any given atoll there will be islets both above and below this threshold. A comparison of the fauna on tiny outer islets and the fauna within the interior of large inhabited islets therefore provides a good idea of which species are strand and which are non-strand. The presence of remnants of either in subsurface layers will provide evidence of the state of the environment at the time that layer was deposited, either strand or non-strand. More will be described on these methods in chapter 5.

These two contrasting environments, strand and non-strand, are marked by distinct differences in soil types, as well as the other more internal zones of non-strand vegetation found on atolls. Due to the recent geological age of all low-lying atolls formed from raised coral reef platforms, C soils composed of “coral fragments, mollusk shells, foraminiferan tests, calcareous alga skeletons, echinoderm parts, and other coral limestone detritus” (Fosberg 1976:258) predominate. On top of this parent material an A horizon of accumulated organic matter develops. Thus the two major components of atoll soils are coral and organic matter (Catala 1975).

Continual storm disturbance creates an unstable state preventing further soil development. Single typhoons are capable of depositing 20-100 cm of detritus material over as much as two-thirds of some islets (McKee 1959) leading to the characteristic A-C banding that has been described before. Stone (1951:2) describes the struggle of this soil development aptly in way that can not be improved upon. It is therefore included below in full...

47 It is evident that the initial development of vegetation is somewhat analogous to lifting one’s self by the bootstraps; plant growth is required to create organic matter which in turn supplies nitrogen, renders certain nutrients available, etc., to permit additional growth. In the early stages following colonizaton by hardy plants, each gain in amount of organic substance tends to favor greater and more diverse vegetational development. Ultimately the extent of this development is reﬂected in the soil proﬁle. Thus a sequence may be observed extending from the wholly unaffected beach sand or boulder rampart of the islands margins to the dark surface soils beneath the lush vegetation of the island interiors.

It is this sequence of soil development observed in the proﬁle and plan view of the island that will be part of the focus of this study.

The development of the soil is closely linked with to the soil particle size of the parent material. The highly permeable coarse sands of the oceanside allow for the high salinity content of the strand zone and limit vegetation growth on which the development of organic matter and the A horizon depend. For this reason the soils of this zone, Shioya sands, are characterized by thin A horizons. Fine sands on the lagoon side are less permeable and hold the freshwater lens well allowing for greater organic matter development and are termed Shioya loamy sands. At the center of the island the greatest organic matter development occurs and these are called Arno soils. It is only in these well-developed A horizons that signiﬁcant amounts of silt- sized particles develop (Stone 1951).

The soil pH of the Shioya sands remains at 8.2-8.3 due to the high amount of calcium carbonate. The accumulation of organic matter will lower the pH signiﬁcantly to the point that acidic soils may eventually develop. Swampy soils characteristic of the pulaka pits will have higher pH levels 8.6-8.9 due to the presence of sulphites. Sterile beach sand is marked by an exceptionally high pH of 9-10.

Human Ecology Studies in the Marshall Islands

Hainline (1965) reported the results of a statistical analysis of land area and lagoon area to population of Micronesian coral atolls that showed a highly signiﬁcant correlation (0.67) of land area to population for all atolls, which was higher than the correla-

48 tion to volcanic islands (0.48). Atolls experiencing repeated, prolonged periods of drought were found to have an even more pronounced correlation of (0.84). Lagoon area was found to only have a signiﬁcant correlation with population for those islands subject to drought (0.67) and a minimal correlation (0.27) for those islands not subject to drought. As the major effect of land area differences would be on the size of the freshwater lens and therefore on the potential for terrestrial food production, these results suggest that terrestrial resources are a more limiting factor than marine resources. Given the abundance of most reef systems of atolls compared to the limited land mass, these ﬁndings are not surprising. Settlement of atolls would therefore favor those islands with greater potential for terrestrial production despite the size of their lagoons.

Table 4-1: Results of Hainline (1965)

island type land mass:population lagoon area:population

coral atoll, non-drought 0.65 0.27

coral atoll, drought 0.84 0.67

volcanic 0.48 -

Bayliss-Smith (1974) added to these ﬁndings a formula whereby the carrying capacity of the island may be estimated by measuring the land suitable for the production of the staple crops with consideration given to the caloric productivity of such staples and the caloriﬁc requirement of each person. Land area is therefore the major variable affecting productivity in two ways, by determining the amount of land available for cultivation and determining the type of plants capable of being cultivated. Agri- culture technology was found to be limited by the necessities of the environment and therefore constant.

“The staple food supply of the population tends to be derived from the activity offering the highest acceptable food return for the lowest effort cost” (Bayliss-Smith 1974:284). Coconut overwhelmingly offered the greatest return and may be seen as the limiting factor accept where social norms placed taro as the more acceptable food choice. The latter case would be focused on large islands capable of providing an abundance of taro. Bayliss-Smith focused his study on such islands and therefore was able to measure population according to the size of taro pits. Smaller islands

49 such as Tokelau have been found to survive on a diet composed of 60-80% coconut (Hooper and Huntsman 1973). The equation created by Bayliss-Smith does however allow for multiple staples to be evaluated.

Intensiﬁcation of terrestrial production becomes more capable over time as an organic base develops leading to an increased carrying capacity. If social controls are able to maintain a constant population then production can move beyond purely subsistence economies to those that incorporate the production of non-subsistence, prestige foods, what Brookeﬁeld (1972) called social economies. Such economies are possible at times of disproportionate low population-high carrying capacity such as at the time of initial colonization or under strict population controls. Social production may therefore develop initially within the colonizing population but the subsequent growth in population following settlement deters any further increase in social production and environmental catastrophes such as typhoon and drought that deci- mate resources may wipe out such economies completely. A common example is dog which is found at the lowest levels following initial colonization on several atolls but is eventually lost.

Epidemics that followed European contact led to decreased populations whereby social controls over population were no longer needed and were forgotten in light of European programs of re-culturation by missionaries. It was under these conditions that the copra trade was able to remove a large portion of coconuts from the subsistence economy in order to form a trade economy. Overpopulation on the other hand would lead to emigration pressure, spur voyaging, and the creation of satellite settlements.

Barrau (1961) divided the low coral atolls into three climatic categories: 1) those that receive less than 40 inches (1000 mm) per year, 2) those that receive between 40 and 100 inches (1000-2500 mm) per year, and 3) those that receive more than 100 inches (2500 mm) per year. The ﬁrst of these groups are composed of the Southern Gilberts, the Phoenix and the Line Islands, all of which are overwhelmingly characterized as what were ﬁrst labeled ‘Mystery Islands’ (Bellwood 1978), those islands that, upon initial contact, were found to have evidence of settlement but no population. Debate waged over the settlement of these islands with initial beliefs presented that settlement was attempted but failed (Anderson et al 2000). Subsequent theories saw

50 these islands as only temporary camps used for the procurement of their rich bird and turtle resources alone (Di Piazza and Pearthree 2001a). Atolls are favored breeding grounds for these animals but initial settlement effectively ends such breeding behaviors. Therefore by remaining unsettled these islands continued to support rich populations of both birds and turtles. The second and third group relate to Hain- line’s study as drought and non-drought atolls respectively.

For those islands subject to drought and lower levels of rainfall land mass plays a more critical role due to the lower freshwater recharge rate and the subsequent en- croachment of salt water. Lagoon area also takes on a greater role due to the limited productive value of the land. Hainline (1965) begins to show the role of rainfall on population size but the limited qualitative variable of drought versus non-drought fails to show the full range of effect. Williamson and Sabath (1982) followed up on Hain- line’s study to further tease out this variable particularly. They chose to limit their study to the Marshall Islands instead of wider Micronesia as a whole to focus on the single island type, atolls, with a uniform technology, and because the island chain lies within a constant rainfall gradient from north to south that can be calculated according to latitude. Their results conﬁrmed Hainline’s ﬁndings adding a correlation between rainfall as an additional variable that produced an index more accurate than land area alone as both variables effectively measure the potential of mesophytic plant production (Williamson and Sabath 1982:78).

Takayama et al (1990) reported a similar relationship for the islands of Kiribati lying directly below the Marshalls, that can be seen as an extension of the same rainfall gradient with a wet north and a dry south though more extreme in its dryness. Wilkes’s U.S. Exploring Expedition noted the absence of breadfruit in the Southern Gilberts (Philbrick 2003), most likely due to climate conditions as it was present in the North. The extreme dryness of the southern islands led the people of these islands to depend on stores of pandanus flour. A common finding throughout the Marshalls and Kiribati was pumice which would float from other islands and was used to fertilize the gardens, a cultural adaptation to living in these extreme environments.

51 Archaeology in the Marshall Islands

Weisler (1999a, 1999b, 2001) took the results of Williamson and Sabath (1982) as the center point of his research design to explore whether their results would hold true for prehistoric populations, measured by the size of settlements and subsurface evidence of taro pit cultivation. Weisler chose four islands in which to focus his study: Utrok, a small island at the driest northern extent, Ujae, a small island, and Maloelap, a large island, both lying in the middle zone of precipitation, and Ebon, a large, wet island at the southern most extent. Rosendahl’s surface surveys (1987) may be used as a quick test of Weisler’s research design. Below is reported the results of the survey compared with precipitation and land area reported by Williamson and Sabath.

Table 4-2: Results of Rosendahl (1987)

island precipitation land area in number of total area of in mm/year square miles surface sites surface sites

Utrok 1515 0.94 - -

Wotho 1882 1.67 0 -

Wotje 1986 3.16 0 -

Likiep 2100 3.96 2 0.845 ha

Ujae 2292 0.72 - -

Lae 2532 0.56 3 4.25 ha

Maloelap 2589 3.79 3 3.02 ha

Lib 2729 0.36 4 6.20 ha

Aur 2790 2.17 4 11.47 ha

Namu 3165 2.42 1 .0015 ha

Ailinglapalap 3352 5.67 6 14.91 ha

Majuro 3648 3.54 4 1.61 ha

Arno 3753 5.00 5 11.36 ha

Mili 4709 5.75 2 0.13 ha

Ebon 5684 2.22 6 6.34 ha

52 Two years after Rosendahl’s survey, Riley (1987) undertook an in-depth study and excavation of Majuro atoll. Over the course of ﬁve weeks he completed a full surface survey that documented 5.0 hectares of surface scatter. This is three times that of Rosendahl’s limited survey. However, it should be noted that the only signiﬁcant prehistoric subsurface deposits were those previously documented by Rosendahl, and Riley’s additions were largely associated with later post-contact sites, giving validity to Rosendahl’s results.

The greatest value of Riley’s work lies though in nine transects of test units distributed throughout the atoll. Many of these proved to be sterile or of historic association, but these only served to further validate the study. The final conclusions were that the earliest major settlement (1900 BP) was to be found to the West on Majuro islet the location of the current traditional village of Laura. It is the largest islet with the greatest freshwater table and largest productive area for Cyrtosperma taro and breadfruit. It is around this islet that the vast majority of the 46 fish traps are found represented by three types of which Type I V-shaped was by far the most prevalent. To the north the second largest islet with the only other area for cultivation was found to be settled at a later date (900 BP) likely to accommodate an expanding population. Shell midden was composed primarily of Strombus in the early southern islets and a diverse variety in the later northern islets showing a change in environment over time. These secondary islets were not fully studied however. The eastern islets were all found to have be limited to military occupation with the southern islets which undergo the greatest storm activity containing no cultural deposits at all. No fish traps were found around these islets. This would become a common pattern in the Mar- shalls with the largest islet being settled earliest and a secondary islet settled later. Such a pattern fosters a constructive field method whereby two different periods of occupation are represented by two separate islets.

Dye’s study of Arno atoll (1987) followed. Arno atoll is the third largest atoll in the Marshall Island archipelago and a full subsurface study proved impossible. A month was given for a complete surface survey. The most frequent surface ﬁnd were paved platforms composed of pebble gravels and alignments of coral uprights in differing states of preservation. Dye warned that these ﬁnds should not be used as an index of prior habitation intensity (1987:298) and their history could not be known but was likely quite recent. Their greatest historical value was in validating the 1947 census

53 by Mason and the subsequent shift in population associated with the American occupation. Surface scatters of prehistoric artifacts uncovered by tree roots toppled by typhoons or agricultural activities were more limited and of greater value. These ﬁnds align well with the survey performed by Rosendahl (1987). Those prehistoric artifacts that were found were not temporally diagnostic beyond the point of contact suggested by shell adzes that were no longer used after the importation of metal by European merchants in the 19th century beginning with the German occupation. The distribution of cyrtosperma pits were of equal value as their cultivation declined at the same time due to the importation of foreign food staples.

Due to the large amount of islets a creative research method was devised for subsurface testing (Dye 1987:311). A weighted random sample of islets was taken according to island type based on soil character. Islets were divided among three types: (type I) islets composed primarily of paleo-reef stone, (type II) islets composed of grey-brown sand which were smaller and underwent recurring geomorphological effects, and (type III) islets of brown-black organic sand that were larger and more stable. These types are analogous to those of Neiring (1956). Greater emphasis was placed on the latter as it is only on these that cyrtosperma pits were to be found and were the locus of prehistoric settlement. Of the ten transects randomly distributed amongst these islet types ﬁve uncovered cultural deposits of differing natures. These ﬁve islets showed differing states of preservation with some of wide dispersal exhibiting disturbance and others of concentrated deposits exhibiting good preservation.

Emphasis was given to understanding the sedimentary history of the islets with an analysis of sediment composition made for most layers expressed in histograms. This analysis evaluated the amount of large particles with high frequencies representing high energy deposition of short duration and low frequencies representing low energy deposition of long duration. Islet formation begins with the accumulation of boulders from high energy events with the secondary accumulation of sands by low energy progradation on the lagoon side. That these processes are well- understood by the islanders is suggested by the creation of walls or artiﬁcial boulder accumulations for the accumulation of land ﬁrst noted by Davidson (1971). Dye found that the presence of cultural deposits correlated with islet width and percentage of sandy deposits showing the importance of the secondary progradation process. Further age may be indicated by the horizontal location from the lagoon due to

54 progradation with those sites further inland of greater age than those at the shore. It is in these sands that the freshwater lens is most stable and plants grow best. Un- derstanding the geologic history of islets is therefore of great value to understanding the potential for prehistoric settlement.

As these studies show, Weisler’s project was not a simple one. Measuring prehistoric settlement requires transects to find the boundary of habitation deposits which must be coordinated to each island by radiocarbon dates. The driest of these islands, Utrok, was found to have a lengthy period of occupation beginning approximately 1800 years ago based on dates from forest clearance of the agricultural area and the deepest habitation layers on the main islet (Weisler 2001:72). Archaeologi- cal evidence of temporary fishing encampments was found eroding from the beach of three different islets and produced several dates ranging between 600 and 1400 BP (Weisler 2001:53-59). Nevertheless, the oldest habitation layers remain little more than sporadic hearth features within the dune sand. Significant habitation marked by a distinct culture layer is dated no earlier than 890 BP. Within this layer several pits that Weisler identifies as breadfruit fermentation pits are found (2001:42-44). Greater evidence is needed to be certain as no botanical remains were found, but it seems logical to surmise that only after breadfruit arboriculture had been established could a large enough population be supported to establish recognizable settlement. Transect excavation found these habitation layers to cover 25 hectares on the largest islet of Utrok, and 4.5 hectares on the second largest islet of Aon, the only two islets large enough to harbor a freshwater lens (Weisler 2001:23-26).

On Ujae, an island of greater precipitation but smaller size, the same methods were carried out. Here, habitation levels were found to cover 25 hectares on the main islet with temporary encampments found on two other islets (Weisler 1999b:10). Two dates represent the earliest habitation at 1660 BP and 560 cal BP, though the earlier of these two is questionable as it was found in culturally sterile sediment (Weisler 1999b:19). The latter date is more secure as it was taken from a hearth. Thus a very similar level of habitation was found on Ujae at a time fairly contemporaneous with that found on Utrok. These two islands are of a very similar size but have different levels of rainfall. This comparison, therefore, shows that rainfall difference had little effect on prehistoric habitation within the last millenium. Both breadfruit cultivation and ﬁsh traps are found on both islands during this period representing signiﬁcant

55 cultural adaptations that provided a method for food storage that would have mediated the effects of rainfall difference. Excavations on the other two islands of Malae- lop and Ebon have not yet been fully reported.

Measuring prehistoric agriculture is even more difﬁcult. On the island of Maloelap, transect excavations across the modern taro pits revealed a continuous buried A horizon that represented the original surface at the time of colonization. Scattered charcoal ﬂecks dispersed throughout the deposit represented the initial burning to clear agricultural land and was dated to 1910 BP. That the layer directly above this buried A horizon appears to be a mixture of the underlying layers below, and more pointedly, that the layer above was radio-metrically dated to 2990 BP and 2550 BP, shows that the overlying layer is spoil dirt from the creation of pits for cultivation at that time (Weisler 1999a:640). Therefore the extent of the overlying layer will show the width of the spoil pile and the extent of cultivation at the prehistoric time of its deposit. Once this is done for each of the islands the data may be compared. So far the full results have not yet been reported.

The most interesting ﬁnding of Weisler’s study as this thesis concerned is that it was the ﬁrst to sample land snails from subsurface deposits on an atoll (Weisler 1999a:647). Land snails were found only in the buried A horizon and the upper cultural layers. Even though no cultural materials were found in the buried A horizon the presence of land snails show the presence of introduced plant species and hence the presence of man, thereby proving the burning was of human origin, a much debated point on many islands.

Summary

The human ecology studies of Hainline (1965), Bayliss-Smith (1974), and Williamson and Sabbath (1982) showed a positive correlation of island size and the amount of rainfall to human population. Rosendahl (1987) showed that a similar correlation existed for the number and size of archaeological sites on the surface. Weisler (1999b, 2001) proposed a project to assess whether a similar correlation existed for subsurface sites. His initial ﬁndings suggest that rainfall may not have been such a limiting factor in late prehistory once cultural adaptations for food storage were developed. Similar adaptations for water procurement may also be expected. Land area therefore appears to be the most limiting factor to human population.

56 At the beginning of this chapter atoll vegetation was described as occurring in zones according to the presence of the freshwater lens which is most developed at the center of the island. Islets were found to have a fully developed vegetation only above 9 acres at which point diversity increases exponentially. Below 3.5 acres islets were found to have only a single zone of strand-line plants. The potential for vegetative growth and agriculture is therefore highly dependent on island size. This explains the correlation documented in the studies described above.

Soil development represents the major link between island size and agricultural potential. Zones of vegetation correspond to zones of soil with the initial strand zones dominated by coarse sand and the interior zones composed of organic-rich silt. The present study will therefore provide a method of soil analysis for prehistoric soil layers to provide a context of population potential to the archaeological assemblages found on atolls.

57 Chapter 5: Methodology

Questions

Throughout the history of atoll archaeology, studies of the island’s paleo-environment have been oftentimes overlooked, likely because it is believed the environment has undergone little change over time. Nothing could be further from the truth. The recent emergence of atolls throughout the Pacific means that they have undergone massive change from a marine environment to a terrestrial environment over a short period of time, during which people have lived on their surface affecting this transition for most of that period. Despite this rapid transition most studies take a synchronic look at atoll vegetation and archaeology looking at a plan-view perspective of surface finds or looking at specific points in time particularly the earliest colonization. This study aims to propose a methodology for viewing the changing environment over time by looking at changes in soil particle size, organic matter content, and land snail fauna through column sampling.

Land snail analysis within archaeology in the past has primarily been focused in Europe (Evans 1972; Dimbleby 1974) and North America (Bobrowsky 1984) where species have been identified with reference to the vegetative environment to which that species prefers or as part of the diet. These analyses are particular to the continental snail fauna which maintains a close association with its particular environmental niche and may grow large enough to provide a significant caloric intake. In contrast, the Pacific Island fauna is most often of such a minute size as to offer little sustenance as a food source and is capable of dispersing to a wider variety of environments. Craig (1995) performed a pilot study aimed towards including land snail analysis within Pacific archaeology following the example of Kirch (1993).

The present study builds off her work and concentrates further on atolls where human introductions and differences in salt-resistency are the primary distinction between species. By following the progression within the soil proﬁle from highly salt- resistant natural colonizers through to successive waves of human introductions, it is believed, land snail analysis can provide a diachronic viewpoint of gardening intensity by which those snails are introduced. The land snail analysis will be complimented

58 by a sedimentary analysis following in the example of Dye (1987) as the ability for gardening intensiﬁcation will depend foremost on soil development. Within this framework, three questions will be asked...

1. Can land snail analysis provide a diachronic viewpoint of gardening change and intensity?

2. Can soil analysis provide a diachronic viewpoint of the development of an atoll environment?

3. Can distinct areas of archaeological excavation on atolls be correlated by common characteristics in the land snail fauna and soil types through the methods used in this study?

In asking these questions the current study may be labeled a study in historical ecology in which the island landscape is viewed as a historical product of the long-term interaction between natural processes and human modiﬁcation. Recently, reports by Yamaguchi et al (2009) and Thomas (2009) have been published on the historical ecology of atolls showing it to be a topic of current interest. The ﬁrst of these docu- ments changes in Cyrtosperma production on Majuro Atoll in the Marshall Islands over time. The second compiles a large body of archaeological and ecological studies on atolls. It is hoped that the following methodology will provide additional means to answer the questions posed in these articles.

59 FIGURE 5-1: Map of the Central Paciﬁc Islands

Field Research

The ﬁeld research for this study was performed on Atafu atoll in the Tokelau Islands as part of the Tokelau Science, Research, and Education Program co-directed by David Addison and John Kalolo over two ﬁeld seasons in 2008 and 2009 for a four week period during both seasons. As with all Master’s research projects opportunism played a role in choosing the island location, however, there are many reasons that made Atafu an appropriate location to test the methodology set forth in this study.

The Tokelau Islands are located 500-600 km north of Samoa with Atafu being the most distant and smallest of these. Atafu, even amongst atolls, is tiny, with a very

60 small land area measuring 2.5 square kilometres (Huntsman and Hooper 1996). Its small size allowed for a large proportion of its area to be sampled by the few excavations for which time allowed. It also means that it suffers from a limited resource base (Addison et al 2009) meaning any settlement will depend on modiﬁcations that should leave clear evidence within the ground. Additionally, a well-known reference of collected oral records, entitled Matagi Tokelau (1991), has been created by the local inhabitants that may be used to reference changes in the agriculture system, such as the historical introduction of pigs and copra production which should have left clear indications in the upper stratigraphy.

More poignantly, oral tradition tells of the abandonment of Atafu and subsequent re- settlement by people of Fakaofo during a period when Atafu and Fakaofo were at war. Fighting between these islands was said to be respectable, in that they would fight for a period of time and then rest and eat together. The story goes that during a friendly bird-catching expedition the men of Atafu devised a secretive plan to kill the men of Fakaofo. When each person came down from the tree with their birds they must say a secret code to alert the people below that they were from Atafu otherwise they would be killed. All but one man from Fakaofo was killed. The people of Atafu then went to Fakaofo and during their campaign mercilessly killed a woman fishing on the reef. In retaliation, Fakaofo devised a plan to fool Atafu whereby they loaded up all of their canoes with two men and large ferns made to look like men and they sailed for Atafu. When the people of Atafu saw all of the canoes full of warriors they fled. The journal of John Byron, the first European to site Atafu in 1765, reports that the island was abandoned at that time giving support to the oral traditions of Tokelau (Gallagher 1964).

During this period of abandonment the island would have been left untended and natural patterns could have taken over from the typically human-modiﬁed circumstances. Resettlement would be accompanied by modiﬁcations to this natural ecology and a re-creation of gardening systems. A study of Atafu therefore offers the opportunity to observe evidence of such a period of abandonment that would substantiate both the oral record and the applied methodology.

Though little archaeological research has been performed in Tokelau, warranting our own efforts at this time, the work that had been performed by Simon Best (1988) set

61 forth a good foundation on which to continue the study. Best spent 20 days excavating on Atafu after having visited both of the other two islands of Tokelau including 22 days of excavation on Fakaofo. Despite his more limited time on Atafu the greatest amount of excavation occurred there: 14 excavation units (9-2x2m & 5-2x1m units) with 11 of these comprising a transect across the main village islet. These excavations showed a typical complex deposition of repeated A-C soil horizons for which the methodology has been designed to provide context. In unit 11 the deposition was composed of six bands over two meters of depth. A rich prehistoric cultural assemblage and a radiocarbon date of 1000 BP attest to early habitation of the island. The remains of pig and chicken were restricted to the upper levels conﬁrming their historic introduction, though dog bone was found throughout. These changes in the terrestrial fauna would likely be accompanied by changes to the gardening system to be observed within the study.

Finally, a 1914 survey placed the land edge of Atafu further inland than it appears today. Reports of local informants would conﬁrm the sudden progradation of the land following a tsunami. This recent deposit offered an opportunity to test the methodology to see if the area’s recent origin could be determined by the methods.

Thus the abandonment and re-settlement of the island, the historic change to the agricultural system, and the recent sediment deposit all provided circumstances, each backed by multiple forms of evidence, by which to test the methodology proposed by this study.

62 FIGURE 5-2: Map of Atafu Atoll showing the locations of Sample Units

Sample Unit Descriptions

TU-1: Deeply stratiﬁed (600 BP to modern)

The ﬁrst unit to be excavated in 2008 was placed within the proﬁle of an open hole that was dug for the construction of a septic tank while we were on the island. This allowed us to monitor the excavation by the backhoe to assess the potential for archaeological materials. Fishbone and pig bone were seen in the back dirt pile as well as a complex stratigraphy warranting further investigation. Permission was sought and granted. The unit was located on the ocean-side of the island though well within the zone of mixed coconut and breadfruit trees and bananas grew voraciously all around.

A one by one meter unit was excavated in 10 cm spits and all contents were screened in nestled 1/8 and ¼ inch screens. The upper 150 cm consisted of dense cultural deposition throughout seven layers of banded coral gravel. Fish bone, bird bone, rat bone, volcanic rock were found throughout, however pig bone was limited to the uppermost Layer I, dog bone was limited to Layers III-VII, and turtle bone was

63 only found in the bottommost Layer VII. Below this lengthy deposit was unmodiﬁed beach deposit. A single radiocarbon date of 660-540 cal BP was obtained from the bottommost layer from a piece of coconut shell (Addison et al 2009).

This unit thus provided a very satisfactory deposit in which to begin the study. The great length of the continuous deposit offered a record of a large, unbroken time span within a single location. The banded stratigraphy offered to break this time span up into distinct periods that could be compared to each other. The changes in the faunal assemblage showed changes in the agricultural system which would likely correspond to changes in the gardening systems exhibited in the land snail assemblage. A column sample was taken and processed in the ﬁeld. For this preliminary study only land snails were collected to assess the potential of the study before any more samples were taken. Identiﬁcations were made in Hawaii under the tutelage of Carl Christensen. The results proved to be of value and led to further sampling in 2009.

TU-2: House platform (400 BP to proto-historic)

The second unit to be excavated in 2008 was placed within the proﬁle of an open hole that had appeared to have been dug quite some time ago and was found to still be open when we returned in 2009. This hole must have been dug for some construction project which has since been delayed or abandoned for reasons unknown. But as any open area provides both an easier mode of excavation and minimizes the overall appearance of destruction the opportunity was taken once permission was granted. This unit lie 30 meters from the lagoon

Excavation followed in the same manner as the first unit. The first two layers were thin and composed of compact sand representing modern construction practices as the area lie well within the modern village with coral gravel covering the entire area and only a few sparse trees providing shade in amongst the houses. Below this first 20 centimeters dark cultural material began and continued for the next meter. At the bottom of the cultural layer an alignment of upright coral slabs represented the remnants of a house foundation. The presence of dog bone within this large cultural deposit suggested that this deposit matched Layers III-VII of TU-1.

64 This unit thus offered a good contrast to the ﬁndings of TU-1. Visually the one meter cultural deposit appeared homogenous, without any of the banding seen in the previous unit, but distinct sampling within the cultural layer offered to assess whether hid- den changes existed. A comparison of the land snail fauna between the two units would also hopefully clarify how the two deposits related. In 2009 the area was found to be unchanged since we last left and the opportunity was quickly taken to a column sample once the intermittent vegetation growth was removed. From these samples on, all material was taken to labs at the University of Otago and followed the methodology as described above.

TU-4, 5, 6: Burials

The first units to be dug during the 2009 season were placed in the area where Best had previously obtained his oldest dates of 1000 BP. Because this date represented the oldest extreme of a date range from 600-1000 BP there was some doubt as to its accuracy. Scientifically speaking the date had as much likelihood of being the same as the 600 BP date obtained from TU-1 as representing 1000 BP which Best chose to interpret. Advances in radiometric science over the past 24 years offered to provide some clarification if we could re-discover the thin layer he had found before. Re- discovering this layer would prove more difficult than we expected due to the presence of three burials above it. Because, none of the current members on the project had the appropriate training in osteology it was determined that re-burial was most appropriate so that the area could be re-excavated the following year when a trained osteologist was scheduled to be joining the project.

While these burials represented a large amount of disturbance in the stratigraphy, a small column of intact stratigraphy was observed in the proﬁle. A column sample was taken from here with great care to avoid contamination from the disturbed layers. Though challenging, the ultimate results proved satisfactory. The challenge would be to determine an estimate for the date of these burials so as to assess the urgency of their study.

TU-7, 8: Settlement or Re-settlement

The next and ﬁnal area to be dug in 2009 was placed in the location where, according to Best’s notes, he had found a large amount of bird, turtle, and ﬁsh bone. As

65 bird and turtle bone often characterize the earliest midden deposits the potential for early dates looked hopeful. In addition a good deposit of ﬁsh bone was needed by Rintaro Ono who would be performing a study of the prehistoric marine foraging practices should such a deposit be found. Permission was granted and excavation began. The area lie 20 meters from the lagoon and was probably closer in times past.

The deposition was found to be very sandy and not very deep leading one to believe that it was not of a very great age. About a meter down a thick layer of ﬁsh bone was encountered providing plenty of material for Dr. Ono’s study. Several pieces of large turtle shell were also found in this layer. Unaltered beach sand was encountered quickly after this dense deposit. No volcanic material was found leading one to believe that no contact was kept with the volcanic islands at this time. A rough adze made of a tridacna shell subfossil also attested to the poverty of raw material at the time. Thus the deposit appeared to be characteristic of a period of colonization. Given the oral history of the abandonment of Atafu, it was possible that this deposit represented the re-colonization of the island by the people of Fakaofo, recorded in legend as being a man named Tonuia (Matagi Tokelau).

This unit therefore offered the challenge of determining whether the deposit represented colonization or re-colonization. If the land snail assemblage was more similar to that found in the later deposits of the previous units it could be said to be re- colonization. If it were more similar to the earliest deposits it could be determined to be initial colonization.

Non-archaeological samples

In addition to column samples taken from archaeologically excavated areas, samples were also taken from three areas of open construction that spanned the island.

The ﬁrst of these samples lay in an area beyond the 1914 land survey meaning it had been deposited very recently or the 1914 survey was unreliable. Modern land snails should be seen throughout the deposit as well as being dominated by coarse typhoon deposited sand.

The second area lay very close to the lagoon in an area that was said to be artiﬁcially built within the memory of some of the older people on the island. If this area was

66 created artiﬁcially over a short period of time the land snail fauna and soil matrix should be relatively homogenous throughout.

The third area lay on the far side of the island from the excavations where little investigation had yet to be done. It was said that this area was bush up until very recently when the road had been extended and the school built. This area therefore offered to provide a view of the natural soil proﬁle.

A comparison of six of these column samples, excluding TU-1, offered a comparative look at the sedimentary history of the areas on which to assess how the island developed over time and what areas would be good for gardening. A comparison of all seven column samples offered a comparative look at the history of changes within the land snail fauna by which to assess how the intensity of gardening practices changed compared to the sedimentary history and a chance to provide a relative dating between these areas based on similar changes throughout.

67 Test Procedure

Four tests were performed to answer these questions: a soil pH test, a soil particle size analysis, a soil organic matter analysis, and a land snail analysis. All combined they will require that soil be taken from a single column sample within each area that is archaeologically tested and any area where additional testing may be wished. Within the study each test will be performed through a variety of methods to assess reliability and accuracy. A ﬁeld method will be described which will be repeated and/ or additional laboratory tests will be performed.

Sample Preparation

A column sample should be taken measuring 20 x 20 centimeters to ensure a large enough sample for each layer. It is best to take this sample from a clean face so that the layers may be easily distinguished. Samples should be taken from within each layer and care should be taken not to cross layers. Where multiple samples may be wished to be taken from within large layers space should be made between samples to ensure distinct sampling. Due to the loose soil matrix typical of coral atolls, it is recommended that when possible an extra ﬁve centimetres surrounding the column sample be cut away intermittently to ensure no material is mixed from above. At least one kilogram of soil should be taken from each layer to ensure a large enough sample of land snails according to current practices (Craig 1995). The bulk sample may then be sieved through a half inch (12mm) and/or quarter inch (6mm) screen to remove large and small pieces of coral and any artifacts. One may wish to weigh the bulk sample, and the subsequent sieved material to assess the quantities of coral within each layer as these proportions may represent periods of active island build-up by the early inhabitants.

For this particular study the samples were then put through a 4 mm screen to make the samples as small as possible while concentrating on the necessary particle sizes. In retrospect, the 6-4mm particle size offered an opportunity to collect larger pieces of charcoal for a colleague performing charcoal analysis. The sub-4mm soil was then bagged in the field ensuring that, where possible, 600 grams of sample material was collected and transported to the archaeology labs at the University of Otago where all analyses were performed. However, the following study will be broken into a field analysis that could have been performed in the field, and will be performed in the

68 field in the future, and a lab analysis that require only that a 100 gram sample be taken. For this particular study 55 samples were taken each weighing 600 grams adding to 33 kilograms that needed to be transported to the lab facilities. The author was fortunate to have received sympathy from the airline staff and was kindly under- charged for this baggage but such a large load clearly offers much difficulty for fieldwork abroad. If the field methods were utilized this load would be reduced to 5.5 kilograms, a much more manageable weight.

Land Snail Extraction and Soil Particle Size Preparation

The extraction of land snails and the soil particle size field test were both performed through the same method, simultaneously. 250 grams of soil was found to be sufficient sized sample. This sample was then put through a set of five graduated sieves (2mm, 0.5mm, 0.25mm 0.125mm, and 0.063mm) using a high-pressure hose with a mist nozzle. One must ensure that the pressure is high enough to push the fine particles through the screens, but only a mist of water is released to ensure the land snail shells are not crushed. This was easier than it sounds requiring only a garden hose, a faucet, and a typical garden hose spray nozzle. Nevertheless, on distant undeveloped atolls without modern plumbing systems this may prove difficult and may require a portable air compressor to provide the necessary pressure. Alternatively, the two preparations may be performed separately. The sediment remaining in the screens was put into individual trays and allowed to dry. Land snail shells could then be easily picked from a larger two screens (2mm, 0.5mm) using a customary magni- fying glass and soft-tip, pliable forceps. These land snail samples should then be carefully stored in small vials and transferred to laboratory facilities for identification. The remaining sediment from all screens was bagged to be weighed for the soil particle size field analysis as described below. Thus this procedure may be performed in the field so long as a proper set of screens are available as well as a water-hose and nozzle.

Land Snail Analysis

Land snail shells were then identiﬁed to species using a dissecting microscope. Pho- tographs were taken of type shells using a digital camera attachment to the dissecting microscope and identiﬁcations of these types were checked with Dr. Carl Chris- tensen, a well-known malacologist amongst Hawaiian archaeologists. The land snail

69 shells in each sample were grouped according to these types and their numbers counted and ﬁled using Microsoft Excel. Due to the low level of species diversity this task is not so demanding as to require an expert and any person with a moderate knowledge can perform the task. Nevertheless, the knowledge to be gained from the exercise should not be underestimated. A full description of species types is given below. This method may be performed in the ﬁeld if a proper microscope is available.

This method was repeated twice for each sample using 250 grams each time where there was enough material to allow for it. Where there was not enough material the same procedure was followed and the counts were then extrapolated to that of a 250 gram sample. In all cases there was no signiﬁcant difference in the counts to warrant caution and one may safely use a single 250 gram sample without fear of error.

Soil Particle Size Field Test

Once the material had been collected from each of the five screens it was then bagged and weighed using a Sartorius electronic weighing balance to a tenth of a gram. These measurements were then entered into Microsoft Excel. The five measurements were then added and subtracted from the total sample size of 250 grams to get a measurement for amount of soil particles below 0.063mm, all silt-sized particles, which would have been flushed through the screens. Thus any error within the test would be added into this final measurement but would be added equally for every sample. The measurements were then calculated as percentages so that samples with less than 250 grams could be compared equally. Just as for the land snail analysis, the procedure was repeated for two samples and no significant difference was noted between the two identical samples, showing the test to be reliable. This test may be performed in the field with the use of a proper balance, electronic where electricity is available or triple-beam balance where it is not.

Soil Test Sample Preparation

Soil test samples (STSs) were taken by sifting air-dried soil through the 2mm sieve. These samples would be used for all laboratory tests including particle size analysis in the Horiba LA-950 and for loss-on-ignition and CNS tests.

70 Soil Particle Size Laboratory Test

The results from the soil particle size field test were then compared to an analysis using the Horiba LA-950 laser diffraction particle size analyzer. The wet mode was utilized so that one gram from each sample was dissolved in distilled water within the machine with plenty of ultrasonic agitation to break up the sample into its individual particles. The wet sample was then diluted until the level of diffraction fit well within the parameters set for the machine. Four measurements were then taken with the two or three that showed significant similarity kept and averaged as the final measurement. These measurements were given as line graphs showing the percentage of different particle sizes on 10 micron increments. This test thus provided a level of accuracy unobtainable by any other method to which the accuracy of the field test could be compared. In all cases the same proportions were regularly repeated to show the field test to be of sufficient accuracy.

One may wish to dissolve the samples in Calgon before adding them to the machine to break up any small silt particles to ensure they do not clump and skew the measurements but as the silt-content of most atoll soils remains relatively low this was deemed unnecessary and over-complicating.

Organic Matter Test

Three different organic matter tests were made. The primary test was a loss-on- ignition test whereby five grams of air-dried sub-2mm sample material (STS) was placed in a dry crucible that had been pre-measured. The crucibles with sample material were then weighed, oven-dried at 100 degrees Celsius and re-weighed, then fired in the furnace at 600 degrees Celsius and weighed once more. The difference in weight between the oven-dried and furnace weights represented the organic matter lost during the firing. This difference divided by the weight of the sample (the difference between the weight of the crucible and the weight of the crucible plus the sample) would then give the percentage organic matter so that all the samples could be compared.

Because atoll soil is high in calcium carbonate, or limestone, from the fact that it is all produced in a marine environment (exhibited by its high pH levels), and calcium carbonate may also ignite in the furnace, an additional test was also made using the

71 CNS machine. This machine ignites the sample at 900 degrees Celsius and all the gas that escapes which consists of the total carbon and nitrogen is then measured to a high degree of accuracy. Because the machine measures total carbon and all the calcium carbonate is ignited the carbon measurement is consistently around 12.01% the measurement for pure limestone. However, “the consideration of organic matter is almost inseparable from that of nitrogen since the two are linked in the soil” (Stone 1951: 3). Therefore the nitrogen levels may be used as a proxy for the amount of organic carbon. The measurements of nitrogen from the CNS machine were found to follow very closely the measurements for organic matter produced from the loss-on- ignition test, proving the accuracy of both tests as such a correlation would not be expected to occur at random.

In addition, soil moisture was tested at the time the loss-on-ignition test was made. Wet soil fresh from the ﬁeld and soil that had only been partially dried were measured in a crucible using the same procedure as before. The difference between the wet soil weight and the oven-dried weight represented the soil moisture content which could then be made into a percentage by dividing by the original soil weight. These measurements were found to closely mimic the relationship of organic matter content between the layers, because in atoll soils the moisture holding capacity of the mineral soil is low (Stone 1951) and water drains quickly where there is an undeveloped A horizon. Most of the moisture available for plants is therefore held within the organic matter and the Ghyben-Herzberg lens. Soil moisture content may then be used as a proxy for organic matter content in the ﬁeld since all that is required is oven-drying the soil at 100 degrees Celsius. This temperature is well within the capability of any conventional oven which should be available on all but the most remote atolls, in which case a small portable oven can be brought. As soil moisture varies with the rainfall all samples should be taken at the same time and tested soon after sampling or kept securely in a sealed plastic bag.

Soil pH Test

10 grams of STS material was diluted in 25 grams of distilled water and shaken vig- orously for ﬁve minutes. A soil pH meter was then inserted until the measurement stabilized. Known standards were used intermittently to calibrate the machine. This test may also be used in the ﬁeld with the proper instrumentation.

72 Systematic Review

Terrestrial Snails of Atafu Atoll, Tokelau Islands

The diversity of land snails on Atafu Atoll, like most atolls (Riegle 1964; Harry 1966), was found to be minimal, composed of only 12 species, 3 of which were natural colonizers and 9 of which were introduced. While the size of the natural fauna is small compared to other island types, the number of introduced species is the same (Wal- ter 2009) A literature review was performed to compile the known details on the species. As was expected only a few species were present of which the majority were prehistoric, historic, or modern introductions, though a few also appeared to have naturally colonized the island. Each will be described in detail below. Identiﬁ- cations were made by Carl Christensen.

Truncatella, Melampus, and Laemodonta were identified as natural colonizers of the island. Surface specimens of these species were found predominately on the outer islets, called uta by the local villagers. These outer islets have undergone far less human modification and therefore more closely resemble the natural environment the species would have first colonized. Subsurface specimens of these species on the village islet were found only in the deeper layers prior to significant human impact and subsequently died off due to human modification of the environment. Natural colonization would have been most effective by drift dispersal and all these species are highly tolerant of saline conditions, while Melampus is highly-resistant to dessica- tion (Mordan and Wade 2008).

Assiminea, Omphalotropis, and Sturanya were identiﬁed as cryptogenic species, a term introduced in 1982 for species that cannot be safely identiﬁed as natural colonizers or early introductions (Carlton 1996). Surface specimens are found in high populations within the strandline environment and throughout the island in lower numbers. Assiminea was found to be the primary species feeding off decaying coconut fronds. Subsurface specimens were found throughout the column sample. It is because these species are so well-adapted to the strandline that makes them cryptogenic. The earliest environment on atolls would be a pure strand environment that these species could naturally colonize. Because Polynesians settled these islands so quickly, the earliest human introductions would also be well-adapted to this environment. Thus it is likely that these species both naturally colonized the island in

73 small numbers and were introduced by the ﬁrst inhabitants in larger numbers. Coco- nut is a cryptogenic plant species. Of these species, Assiminea appears the most natural, Sturanya to have been introduced in the prehistoric, and Omphalotropis appears to have been more heavily introduced in historic times.

Allopeas and Liardetia were identiﬁed as early prehistoric introductions. This assessment is well-supported in the literature. Surface specimens were found predominately in the non-strand environment as were all of the following introductions. Allopeas was found in greatest numbers beneath the breadfruit trees, while Liardetia was found living off the banana trees. Subsurface samples began in the deeper cultural layers, with Allopeas maintaining numbers throughout the cultural layers, and Liardetia found in higher numbers only within the early cultural layers.

Lamillidea and Gastrocoptus were identiﬁed as late prehistoric introductions. This assessment is well-supported in the literature. Surface specimens were found in non-strand environments of mixed vegetation. Subsurface specimens were recur- rently to begin in prehistoric cultural layers above the earliest cultural layers.

Dramatic increases in Assiminea and Omphalotropis were identiﬁed as the result of the historic introduction of the copra industry. As mentioned before these are both strandline species that dwell beneath the coconut and so it should be expected that a dramatic rise in coconut production would correlate with a dramatic rise in these species’ numbers.

Subulina and Huttonella were identiﬁed as late historic or modern introductions due to their restricted presence in the uppermost layer, and their dispersal by modern commerce as described in the literature. Of these Huttonella appears to be the more modern while Subulina may originate from the late historic.

74 FIGURE 5-3

Family Subulinidae

Allopeas gracile Hutton, 1834

Allopeas gracile, formerly identified as Lamellaxis gracilis, is regarded as the most widely distributed species of land snail in world (Pilsbry 1906) largely attributed to its spread by Polynesians. It has been noted in early Lapita contexts in Tikopia (Christensen and Kirch 1981) and Tonga (Kirch 1988), as well as Eastern Polynesian contexts in the Mar- quesas (Rolett 1989) and HawaiÌ (Christensen and Kirch 1986). In addition it has been observed in American Samoa at the Toàga site (Kirch 1993) and by the author at Fatu-ma-Futi. It therefore appears to have spread to every island group and is a ubiquitous presence in Poly- nesian deposits.

Subulina octona Bruguiere, 1792

This species was noted on Jaluit atoll in the Marshall Is- lands as early as 1904 (Schnee), however, the antiquity of its presence is questionable. It is believed to be native to tropical America and to have been dispersed by commerce in the late 19th century to its present circumtropical distribution (Cooke 1926, Solem 1964, Christensen and Kirch 1981).

Family Assimineidae

Assiminea sp.

The genus Assiminea is a well-known strandline-dwelling species distributed throughout Southeast Asia and Oceania (Abbott 1958). It prefers brackish water habitats and is an amphibious snail in the process of emigrating from the sea to the land. It is therefore well-adapted to life on atolls, landforms in the process of making the same transition. It was the most abundant snail found at the To`aga site in the eastern Manu`a islands of the Samoan archipelago (Kirch 1993). Ulithi (Harry 1966)

75 FIGURE 5-4

Omphalatropis sp.

Species of the genus Omphalatropis have been described from the Marshall Islands (Pease 1860, Marshall 1950), Funafuti (Hedley 1899), Vanuatu (Solem 1959), New Caledonia, Guam, Ulithi atoll (Harry 1966), and Tikopia (Christensen and Kirch 1981). It is thus found on a variety of island types all west of Tokelau. It exhibits a remark- able variety of colors but a very constant shell shape, the latter being most important to the identiﬁcation of subfos- sils.

Family Pupillidae

Gastrocoptus pediculus Shuttleworth, 1852

The original habitat of G. pediculus is speculated to be the coastal environments between the Philippines and New Caledonia, however, its strong liking for coconut groves made it extremely adaptable to life around Polynesian habitations and has led to its vast distribution throughout Oceania where it has emigrated by sticking to coconut and other food materials over many thousands of years of inter-island canoe voyages of the Polynesians. It has been found on almost every inhabited atoll and high island of Oceania (Pilsbry 1916-1918). It was ﬁrst noted in the Marshall Islands by Pease (1860).

Family Achatinellidae, formerly Tornatellinidae

Lamillidea pusilla Gould, 1847

L. pusilla has an extensive distribution from the Mariana to Mangareva and is believed, with little doubt, to have been spread by human agency during the Polynesian migrations (Cooke and Kondo 1960). Members of this species were documented on Rongelap atoll (Reigle 1964), and another member of its genus, albeit a tentative species identiﬁcation, was observed on Ulithi atoll exhibiting a propinsity for life on such environments (Harry 1966).

76 FIGURE 5-5

Family Helicarionidae

Liardetia sp. possibly L. samoensis Mousson, 1865

The genus Liardetia contains widely distributed species, likely due to the agency of man (Baker 1938) of which Liardetia samoensis is the most widely distributed from the Bismarcks to the Marquesas (Solem 1959) and was noted on Rongelap atoll by Reigle (1964). It is likely that the specimens found on Atafu atoll belong to this species as well.

Family Helicinidae

Sturanya sp. Wagner, 1905

The dispersal of this species extends from the Solomons to the Cook Islands (Peake 1969). It is currently held to be a synonym of Pleuropoma (Cowie 1997) a few specimens of which were noted at To`aga (Kirch 1993).

Family Streptaxidae

Huttonella bicolour, formerly Gulella bicolor Hutton

This species has been found on Ulithi and Fais atolls as well as Mauritius, India, Malaya, Brazil, French Guiana, Barbados, Panama, and elsewhere (Harry 1966). Such a wide and varied distribution makes modern commerce the most likely mode for its emigration. It is typically less abundant due to its carnivorous habits. Only a few specimens were found in the uppermost layers.

77 FIGURE 5-6

Family Truncatellidae

Truncatella guerinii A. & J. Villa, 1841

T. guerinii is widely distributed throughout the Paciﬁc and may be found at the high-tide mark of the intertidal zone. Species within the Family Truncatellidae range from marine to terrestrial and therefore tend to be highly tolerant of saline conditions (Cernohorsky 1978). This species was very common on Rongelap atoll (Reigle 1964).

Family Ellobiidae

Melampus luteus Quoy and Gaimard

M. luteus is common throughout the Paciﬁc and like most ellobiids is found in brackish environments. Its ability to survive despite loosing 80% of its water make it especially resilient to harsh conditions (Mordan and Wade 2008) and capable of surviving where other species could not.

Laemodonta sp

In these air-breathing ear-shells the gills of marine prosobranchs have been replaced by a modiﬁed lung. Like the previous two species they inhabit the fringe between sea and land making them appropriate to naturally colonizing the early atoll environment as it rose from the sea. Only one specimen was found in early layers from this transition.

78 Marine Snails Identiﬁed within the Study

Land snails were not the only mollusks to be found in the samples. Several different species of marine mollusca were found abundantly in the deeper layers and in de- creasing numbers as the soil became more terrestrial. These specimens were grouped the same as the land snails according to common shape and counted. Identiﬁcation was done to the family level as little more information could be gleamed beyond that and the number of genus and species made the task impractical for the purposes of this study. Instead only a few of the more common specimens were included in the study. These were photographed and identiﬁed below.

FIGURE 5-7

Family Rissoinidae

Rissoina (Phosinella) balteata Adams & Reeve, 1850

The most common species found was R. balteata identified by the striations and axial ribs that cover its surface. It is very small in size, cosmopolitan in distribution, and inhabits the intertidal region of the tropical Pacific (Cernohorsky 1978:44). Within this study, measurements of their numbers define layers as deposition from an intertidal environment.

Rissoina sp.

Also very common though in less numbers than R. balteata was a distinctive shell of the Family Rissoinidae which could not be identiﬁed beyond genus. Measurements of their numbers mimicked R. balteata helping to further deﬁne the intertidal zone.

79 FIGURE 5-8

Family Triphoridae

Triphora granulata Pease, 1869

Also present, though not as abundant, was T. granulata, which is easily identiﬁed by its aperture which is on the left side instead of the right, and by the spiral rows of small beads that cover its surface. It is very small, world-wide in distribution, and inhabits the intertidal zone on the underside of coral rocks covered by marine sponges on which it feeds (Cernohorsky 1978:168). Within the study, its numbers add additional support to the deﬁning of the intertidal environment.

Family Trochidae

In more limited numbers are members of the Family Tro- chidae, top-shells which subsist on protozoans and detritus matter, and inhabit areas from the intertidal zone to a depth of a few fathoms (Cernohorsky 1978:32). Within the study, the presence of these species, help to deﬁne a more transitional marine environment before the development of the intertidal.

Family Epitoniidae

A few members of the Family Epitoniidae were also noted. These species are elongate with axial ribs, and live in weedy coarl-sand in shallow and deep water (Cernohorsky 1978:166). There presence de- ﬁned more marine environments. They may be distinguished from Rissoinidae by their more pronounced axial ribs and from Truncatella by their more slender shape.

80 Gastrocoptus Sturanya sp pediculus Liardetia Assiminea sp. samoaensis Huttonella Subulina Lamellidea bicolor octona pusilla Omphalotropis sp. Allopeas gracile

1 mm

Family Triphora Rissoina Trochidae balteata granulata Melampis Rissoina sp Truncatella luteus guerinii

FIGURE 5-9: Illustrations of Snail Shells to a Common Scale Surface survey of modern snails

Before any column samples were analyzed a thorough survey of the surface of the village islet was made to assess the modern land snail fauna. Samples of leaf matter in which land snails live and off which they feed were shaken in a screen with a closed tray beneath it. In addition, a pinch sample was made of the surface sediment in which a handful of soil was collected and sieved in the same manner as subsurface samples. All specimens were identiﬁed to the species described above.

Careful notation was made as to the vegetation type beneath which these samples were made in order to assess any differences in the land snail fauna pertaining to vegetation type. Coconut, pandanus, breadfruit, and banana were the main vegetation types, of which, coconut and pandanus are both strand species, while banana and breadfruit are both non-strand species. Differences were seen between strand and non-strand faunas, however little to no difference was seen between vegetation types within strand and non-strand groups.

Liardetia was only found in non-strand environments. As an early introduction it thus provides a reliable indication as to when the non-strand environment ﬁrst developed.

Huttonella was also found only in the non-strand environment. However, as a modern introduction it is of little use in determining the paleo-environment.

Lamillidea was found primarily in the strand environment though a couple specimens were found in the surface pinch samples in the non-strand environment. These specimens may be attributed to the movement of leaf matter from the strand environment for mulching, which happens occasionally. No living specimens were found in the leaf matter of the non-strand environment. A high number of this species would therefore support the identiﬁcation of a layer as resulting from a strand environment.

82 Table 5-1: Surface Samples of Modern Land Snails

Table 5-2: Surface Pinch Samples of Modern Land Snails

83 Survey of Uta, the outer islets

A survey of the outer islets was also made. The sediment of these islets was found in all cases to be mixed by recurrent storm activity with only a thin A horizon developed since the last major typhoon that was described by the locals to have occurred in 1996. These islets therefore typify what the early archaeologists expected of atolls, a ravaged island environment with no stratigraphy. It is thus only on the village islet that continual human modiﬁcation has created an environment that can with- stand storms and develop stratigraphy. These outer islets therefore represent a much more natural state though minor modiﬁcation has occurred and a few introduced species may be expected.

Samples were taken from the surface of these outer islets as well as just below the A horizon between twenty and thirty centimeters below the surface. Due to their more natural state of these islets it was expected that species capable of naturally colonizing these islets would be favored over the few introductions that may be accidentally introduced.

Truncatella was found to be the most prevalent species on these outer islets in both the surface and subsurface samples. Its high numbers on the outer islets contrasts greatly with its relative absence on the village islet. Thus it finds a niche in the salt- laden outer islets where it need not compete with so many other species. This fits well with its identification as a natural colonizer.

Assiminea, Omphalotropis, and Sturanya appear in comparable numbers as they do on the village islet. This supports their identiﬁcation as cryptogenic species capable of both naturally colonizing the low islets as well as being introduced into the strand- line gardens.

Allopeas, Lamillidea, and Gastrocoptus are all found in low numbers showing them to be capable migrants easily introduced into strand environments.

84 Table 5-3: Land Snail Samples from Uta

Much more prevalent on the outer islets, however, were the marine species from their continual deposition by wave and storm activity exhibited by the high numbers of ‘other marine’ species including species from all depths.

Table 5-4: Marine Snail Samples from Uta

85 Ch. 6 Results

In this chapter the results of the tests will be given for each column sample. First, the profile of the area will be described with specific reference as to the depth and layers from which the samples were taken. A summary of the unit will be given to re- familiarize the reader with its significance in which the results will be interpreted. Second, graphs and tables will outline the specific results for the more critical reader who may wish to make his or her own interpretations. Generally, these graphs and tables will be organized to show the results of the soil analysis first followed by the more detailed results of the land snail analysis.

TU-1: Deeply Stratiﬁed (600 BP to modern)

Test Unit 1 was the only column sample to be taken in 2008 as a preliminary assessment of the study’s potential. Samples were taken within each layer of the pro- ﬁle, but only those included in the study are shown within the grey boxes. Layer VII consisted entirely of loose coral with little to no soil present and so a sufﬁcient sample was unable to be obtained. The lack of soil leads to the belief that this layer may have been deposited through human activity. A date of

660-540 cal BP was obtained from a piece of FIGURE 6-1: Proﬁle of TU-1 coconut endocarp in this layer providing a date for the settlement of this particular area (Addison and Kalolo 2009). Layer VIII consisted entirely of marine shell that was not identiﬁed beyond being of marine origin. The complete absence of terrestrial

86 snails show that it was a pristine beach prior to the deposit of Layer VII. Layer I contained an abundance of material that was not able to be identified in the short time given at that point in time. However, the extreme amount of material aligns with findings in other areas associated with a period of agricultural intensification that likely represents the onset of the copra industry in historic times. As pig bone, believed to be introduced in historic times, was only found in Layer I, this assessment seems logical. No soil samples were taken at this time, only a sample of land snails. As the table and graph show, there is a clear division between two periods in prehistory: an upper/late period composed of Layers II, III, & IV, and a lower/early period composed of Layers V & VI. In the early period there are balanced populations of Omphalotropis, a cryptogenic species, and Allopeas, an early prehistoric introductions. The balance between these populations is characteristic of a natural ecology with little modification. Within Layer V, the cryptogenic species Assiminea increase in numbers and Sturanya is introduced preluding the unbalanced populations of the later period when Assiminea and Allopeas come to dominate. These unbalanced populations are characteristic of a more modified environment. It is during this period that several new species are also introduced including Lamillidea and Gastrocoptus. The presence of Truncatella throughout may be attributed to the closeness of the area to the ocean and its ability to repeatedly colonize the area through natural drift dispersal.

One will note the lower counts in Layer III compared to the layers above and below it. As the same proportions of different snail species are maintained throughout all three layers, this episode in not attributable to modiﬁcation in kind as that between the two periods which is marked by the introduction of new snail species attributed to the introduction of new plant species. Instead, this decline in numbers is the result of modiﬁcation to the environment in scale. A similar episode will be seen in all four archaeologically investigated areas and is believed to represent forest clearance based on changes in the organic matter content described more fully for TU-2.

87 FIGURE 6-2

Table 6-1: Results from TU-1

88 TU-2: House platform (400 BP to proto-historic)

Test Unit 2 was excavated in 2008 but was not sampled until 2009 as it was part of a proﬁle of an open construction site that had gone unaffected between the two ﬁeld seasons.

In 2008 the profile was described as being very homogenous with Layers I & II clearly resulting from modern construction and the entirety of the prehistoric component contained within roughly 110 FIGURE 6-3: Profile of TU-2 centimeters of a single deposit labeled Layer III. The analysis of TU-2 therefore focused on assessing change within this single deposit based on seven samples within the layer. A steady decline in marine shell was seen through the bottom half of Layer III, from the bottom of the excavation up to 78 cmbs. At the same time a steady increase in terrestrial snails occurred at the same rate as the marine snail decline. This smooth inverse change may be attributed to relatively constant environmental change. From 45 to 68 cmbs, lower numbers of terrestrial snail material were collected. This drop in population may be correlated with the drop in Layer III of TU-1. At 30-37 cmbs, extraordinarily high numbers of terrestrial snails were collected matching Layer I of TU- 1. Thus agricultural intensification occurred at an equal scale in both of these areas.

Layer III of TU-2 appears to correlate with the late prehistoric period from 78 to 130 cmbs, based on the presence of Lamillidea and Gastrocoptus. A radiocarbon date of 400 BP within the middle of this area supports that conclusion. This deposit appears to correlate to Layer V of TU-1. The presence of Subulina, a late historic/modern introduction, in Layer I and the uppermost part of Layer III and the decline in terrestrial

89 snails place it after the end of the copra industry. Layer II contains no terrestrial snail and few marine marking it as beach material likely transported for construction purposes.

As Stone first commented, “observations on soil organisms on Arno atoll show ap- preciable numbers and the expected relationship between numbers and organic matter” (1951:4). Measurements of organic matter content within these samples give the opportunity to assess whether this statement is true of Atafu atoll as well. As seen in the table below a general steady accumulation of organic matter is observable in all three tests, matching the steady growth in the land snail populations. The observant reader will, however, note a drop in organic matter in the sample from 58-68 cmbs at the same point that the land snail population drop. This drop in organic matter may be attributed to forest clearance and human modification in the environment following the observations that “disturbance of the native vegetation leads to a rapid reduction in the organic matter content and thinning of the A horizon (Morrison and Seru 1986). Thus, at the time of this deposit, the forest was cleared of a significant amount of vegetation, at which time the overlying coral lens (45-52 cmbs) was deposited based on the similar land snail characteristics between the two. This forest clearance likely represents the beginning of copra planting after which an explosion in land snails and organic matter results. This drop matches Layer III of TU-1.

These changes are mimicked in the particle size analysis. A steady accumulation of silt matches the accumulation of organic matter. Inversely the amount of coarse sand decreases as the inﬂuence of wave deposited sediments diminishes. Fine sand increases gradually as the soil develops. A hiccup in this development is noticeable after sample 18.

90 FIGURE 6-4

4-2 mm TU-2 particle size 2.0-0.5 mm 70 0.5-0.063 mm <0.063 mm

60 50 TU-2 House platform 40 (400 BP to proto-historic) 30

0 [I]0-8 [II]10-17 [III]19-26 [III]30-37 [III]45-52 [III]58-68 [III]78-92 [III]100- [III]110- [IV]130-148 110 120

Table 6-2

TU-2 organic matter content moisture % organic % Nitrogen %

[I]0-8 [II]10-17 [III]19-26 [III]30-37 [III]45-52 [III]58-68 [III]78-92 [III]100-110 [III]110-120 [IV]130-148 Table 6-3

Table 6-4 terrestrial TU-2 snail marine 350

300

250

200

150

100

0 [I]0-8 [II]10-17 [III]19-26 [III]30-37 [III]45-52 [III]58-68 [III]78-92 [III]100- [III]110- [IV]130-148 110 120

91 FIGURE 6-5

TU-2 land snail Assiminea 120 Omphalotropis 325 Allopeas Subulina Lamellidea 100 Gastrocopta Liardetia Sturanya Truncatella 80

0 [I]0-8 [II]10-17 [III]19-26 [III]30-37 [III]45-52 [III]58-68 [III]78-92 [III]100- [III]110- [IV]130-148 110 120 Table 6-5

R. balteata TU-2 marine snail R. sp 70 T. granulata Trochidae Epitoniidae other marine 60

0 [I]0-8 [II]10-17 [III]19-26 [III]30-37 [III]45-52 [III]58-68 [III]78-92 [III]100-110 [III]110-120 [IV]130-148 Table 6-6

92 From the results so far we are able to answer all three of our research questions in the positive: a diachronic perspective of the environmental change of both areas has been obtained by which they can be correlated. In TU-2 a single homogenous layer now shows the steady accumulation of land snails and organic matter attributable to constant gardening activities with low level intensiﬁcation. Also seen within the same homogenous layer is forest clearance and the development of the copra industry. These developments may be correlated to changes in TU-1’s proﬁle, according to the table below...

FIGURE 6-6

TU-1 TU-2 TU-4 TU-6 TU-7 TU-8 0 cm modern modern modern Layer I Layer I Layer II Layer II mass of 20 cm copra industry copra industry copra industry Layer III Layer III charcoal & white ash Layer IV Layer IV 40 cm Layer V forest clearance forest clearance Layer VI forest clearance Layer V late prehistoric 60 cm late prehistoric Layer VI late prehistoric Layer VII

80 cm Layer VII middle prehistoric middle prehistoric 100 cm

early prehistoric natural Layer VIII 120 cm

natural

Table 6-7: Proﬁle Alignment of TU-1 & TU-2

TU-1 TU-2

modern Layer I, 0-25 cmbs Layer I-III, 0-26 cmbs

copra industry Layer II, 25-45 cmbs Layer III, 30-37 cmbs

forest clearance Layer III, 45-55 cmbs Layer III, 45-68 cmbs

late prehistoric Layer IV, 55-90 cmbs Layer III, 78-92 cmbs

middle prehistoric Layer V, 90-100 cmbs Layer III, 100-120 cmbs

early prehistoric Layer VI,110-140 cmbs no deposition

93 TU-4,-5,-6: Burials

These three test units all comprised a single three by one meter area first opened up because it was in the same location where Simon Best’s (1988) previous excavation found its oldest date. This single date has been re-calibrated to 1100-600 BP (Addi- son & Kalolo 2009; Addison et al 2009)representing a significant error range. It was therefore deemed worthwhile to obtain more secure dating material. The excavation area was widened when burials were encountered in an attempt to subvert these delicate finds. Eventually, more burials were encountered and the area had to be abandoned until the following year when the burials could be removed by an trained biological anthropologist. Considerations of this area shall be focused around the age of the burials and the likelihood of finding more ancient deposits. Care was taken to avoid mixed layers.

FIGURE 6-7: Proﬁle of TU-4 & TU-6

Immediately noticeable is that the layer in which the burial pit connects to is marked by the extraordinarily high numbers of land snails as well as a high organic matter content associated with the historic copra industry. Thus, it is unlikely that these burials are of any distant age unless they were disturbed from deeper layers during gardening activities or purposefully reburied. Further signiﬁcant quantities of land

94 snails only begins 75 cm below the surface with substantial amounts of marine shell in layers below. Thus while the presence of ancient buried cultural layers in this area are still possible, any such layers would be discontinuous from the upper deposition and would represent a distinct period separate from the settlement of this particular area. A look at the soil particle size analysis gives greater hope, however.

A look at the line graph will show that the proportion of coarse sand to silt have flip- flopped throughout the bottom layers of the profile more than once. These findings are indicative of an environment in flux either from natural cycles of storm deposition or human modification over distinct episodes. A lack of cultural material favors the former interpretation. A shifting sand environment therefore likely persisted at this area for much of the island’s history up until layer III when the area stabilized and the deposit becomes noticeably more cultural. The sudden appearance of land snails in Layer IV support this assessment. A similar shifting environment will be seen in TU-8.

Notable is the decline in Assiminea in the grey cultural deposit at the time that people ﬁrst begin to have a signiﬁcant presence in the area. This decline may be associated with the same forest clearance seen in the other units. Thus the bulk of the deposit occurs after this time.

95 FIGURE 6-8

4-2 mm TU-4 particle size 2.0-0.5 mm 50 0.5-0.063 mm <0.063 mm 45

30 TU-4: Burials,

20 historic or 15 pre-historic? 10

0 [I] 8-13 [III] 20-26 [IV] 46-54 [V] 60-65 [VI] 70-74 [VII] 90-98 [VIII] 110-120

Table 6-8

TU-4 organic matter content moisture % organic % Nitrogen %

[III] 20-26 [IV] 46-54 [VI] 70-74 [VII] 90-98

Table 6-9

terrestrial TU-4 snail marine Table 6-10 600

500

400

300

200

100

0 [I] 8-13 [III] 20-26 [IV] 46-54 [V] 60-65 [VI] 70-74 [VII] 90-98 [VIII]110-120

96 FIGURE 6-9

TU-4 land snail Assiminea 120 Omphalotropis 397 Allopeas Subulina Lamellidea 100 Gastrocopta Liardetia Sturanya Truncatella 80

0 [I] 8-13 [III] 20-26 [IV] 46-54 [V] 60-65 [VI] 70-74 [VII] 90-98 [VIII] 110-120

Table 6-11

R. balteata TU-4 marine snail R. sp 70 T. granulata Trochidae Epitoniidae other marine 60

0 [I] 8-13 [III] 20-26 [IV] 46-54 [V] 60-65 [VI] 70-74 [VII] 90-98 [VIII] 110-120 Table 6-12

97 TU-7,8: Settlement or Re-settlement

Test units 7 & 8 were excavated as a single one by two meter area due to the abundance of faunal material found typical of an early colonizing diet, such as large amounts of turtle and bird bone. A distinct lack of volcanic material compared to the other excavated areas also characterized the deposition as dating from a time when little to no contact was maintained with volcanic islands. Based on the artifact assemblage this area therefore appeared to represent colonization from another atoll. Placing such a colonization within a timeframe would therefore be of great value.

FIGURE 6-10: Proﬁle of TU-8 & TU-7

The deposition was very shallow extending to roughly 90 cm below the surface. A thick layer of bone material was very noticeable midway through as Layer V. The concentration of bone likely accounts for the high measurements of organic matter in this layer. The particle size analysis shows a chaotic development prior to the cultural layers that appears markedly natural. Following the cultural deposit of Layer V, however, the area becomes much more stable. This scenario matches that seen in TU-4. Thus both areas were under greater inﬂuence from the natural forces of the lagoon prior to the occupation of the area. Such a prolonged period of natural depo-

98 sition may be associated with abandonment as described in historical accounts and oral traditions.

Most poignant in the analysis is that terrestrial snails are present throughout the pro- ﬁle and even in the bottom-most deposit that appears to be no more than beach sand. The distinct nature of the two lower deposits, Layers VI & VII, are evidence against mixing. That introduced land snails, Allopeas, Lamillidea, Gastrocoptus, and Liardetia, were already heavily populating the area prior to cultural layers, in deposits that appear to be natural is clear evidence that they had been well introduced before and that these deposit represent a period following initial settlement, and therefore re-settlement. A radiocarbon date of 530 BP from between Layers VI and VII (Addi- son personal communication) further support these assessments. Above the layer of bone material, Layer V, a change in land snail populations is seen. Many of the early introductions, all but Assiminea and Allopeas, are absent above the cultural layers. Further distinguishing the two periods from each other is a change in soil pH from a natural beach level of 9.4 to a lower cultural level of 8.8 due to the incorporation of charcoal that darkened the soil.

As described before, the oral legends of Atafu tell of the abandonment of the island and the subsequent re-colonization by Tonuia from Fakaofo. It seems likely that this deposit represents that time of Tonuia. The predominance of bird bone depicts a diet at the beginning of the colonization of an island that has been left in natural state for a prolonged period of time during which high populations of bird could have developed. The lack of volcanic material supports colonization from another atoll with little to no contact with a volcanic island. The soil deposits below the cultural layers appear natural but contain high amounts of introduced terrestrial snails associated with the late prehistoric. The date of 530 BP therefore appears to result form Layer VII, after which late prehistoric snails were introduced in Layer VI. In Layer V the island was re-colonized after a period of abandonment, the land form stabilized with the occupation, and organic matter began to re-develop along with a new land snail fauna with fewer introductions. It is also here that we begin to see that the period of forest clearance aligns with the re-settlement of the island, a sensible conclusion as the process of re-settling an island after a period of abandonment would require that the natural vegetation be cleared to make way for gardening activity.

99 FIGURE 6-11

TU-8 particle size 4-2 mm 2.0-0.5 mm 60 0.5-0.063 mm <0.063 mm

50 40 TU-8: Settlement 30 or Re-settlement 20

0 [I] 4-8 [II] 11-15 [III] 22-32 [V] 42-48 [VI] 55-65 [VII] 90-100

Table 6-13

TU-8 organic matter content moisture % organic % Nitrogen %

[I] 4-8 [II] 11-15 [III] 22-32 [V] 42-48 [VI] 55-65 [VII] 90-100

Table 6-14

terrestrial TU-8 snail marine Table 6-15 120

100

0 [I] 4-8 [II] 11-15 [III] 22-32 [V] 42-48 [VI] 55-65 [VII] 90-100

100 FIGURE 6-12

TU-8 land snail Assiminea 100 Omphalotropis Allopeas Subulina 90 Lamellidea Gastrocopta 80 Liardetia Sturanya 70 Truncatella

0 [I] 4-8 [II] 11-15 [III] 22-32 [V] 42-48 [VI] 55-65 [VII] 90-100

Table 6-16

R. balteata TU-8 marine snail R. sp 40 T. granulata Trochidae Epitoniidae 35 other marine

0 [I] 4-8 [II] 11-15 [III] 22-32 [V] 42-48 [VI] 55-65 [VII] 90-100

Table 6-17

101 Based on the analyses performed thus far we may now de ne seven periods according to a set of environmental changes common throughout the village islet as shown in the table below... Table 6-18

Time periods Dening Characteristics

modern Subulina and Huttonella introduction; modern construction layers

copra industry Massive increase in terrestrial snails; increase in organic matter

forest clearance Marked decrease in terrestrial snails; drop in organic matter

late prehistoric Lamillidea and Gastrocuptus introduction

middle prehistoric Sturanya and Liardetia introduction; unbalanced ecology

early prehistoric Assiminea, Omphalotropis, Allopeas introduction; balanced ecology

natural chaotic !uctuations in particle size; a predominance of coarse sand

All four of the archaeologically tested areas may now be aligned according to these time periods as shown in the next gure...

FIGURE 6-13: Profile Alignment of TU-1, TU-2, TU-4, & TU-8 100 Year-old Progradation

From local reports and the historic land survey, this area was believed to be the result of progradation within the last 100 years. The area was tested to see if such could be interpreted if it were not known be- forehand and in order to verify the accuracy of local reports.

The high levels of marine snails compared to terrestrial snails throughout the profile show the continuous marine origin of this areas deposits. Its soil particle size analysis shows chaotic changes below layer IV with a continuous predominance of coarse sand throughout. From these tests it is clear that the area has always remained marine. This would be expected of a deposit that originated from progradation and has had little soil development. This sequence should remind one of the lower layers of TU-4 and TU-8 which showed similar chaotic fluctuations in soil particle size and marine characteristics. The initial settlement of these two archaeologically tested areas may then have looked very similar to the current FIGURE 6-14: 100YR Profile settlement of this recently developed area. It is difficult to place this area in the time-frame with the other areas that have been tested on the island for the simple reason that it sits outside that time-frame. How- ever, It is clearly an area of progradation with little soil development which would be expected to have only developed recently. The natural trend shall lead to soil development and increased horizontal progradation. That this process has begun is depicted in the drop in pH, the darkening of the soil and the rise in moisture content associated with the incorporation of charcoal residue by the first cultural deposits beginning in Layer V. Therefore while progradation may be easy to see through these tests, such geomorphology is difficult to date without making a few assumptions. Nevertheless, the data aligns well with the local reports and historic land survey.

103 FIGURE 6-15

100YR particle size 4-2 mm 80 2.0-0.5 mm 0.5-0.063 mm <0.063 mm 70

50 100 Year-old 40 Progradation 30

0 [I]0-5 [I]5-10 [II]10-20 [II]20-25 [III]28-34 [IV]38-46 [V]50-57 [VI]60-66 [VI]68-72 [VII]78-86

Table 6-19

100 YR organic matter content moisture % organic % Nitrogen %

[I]0-5 [I]5-10 [II]10-20 [II]20-25 [III]28-34 [IV]38-46 [V]50-57 [VI]60-66 [VI]68-72 [VII]78-86

Table 6-20

Table 6-21 terrestrial 100YR snail marine 90

0 [I]0-5 [I]5-10 [II]10-20 [II]20-25 [III]28-34 [IV]38-46 [V]50-57 [VI]60-66 [VI]68-72 [VII]78-86

104 FIGURE 6-16

100YR land snail Assiminea 16 Omphalotropis Allopeas Subulina 14 Lamellidea Gastrocopta Liardetia 12 Sturanya Truncatella

0 [I]0-5 [I]5-10 [II]10-20 [II]20-25 [III]28-34 [IV]38-46 [V]50-57 [VI]60-66 [VI]68-72 [VII]78-86 Table 6-22

100YR marine snail R. balteata 45 R. sp T. granulata Trochidae 40 Epitoniidae other marine

0 [I]0-5 [I]5-10 [II]10-20 [II]20-25 [III]28-34 [IV]38-46 [V]50-57 [VI]60-66 [VI]68-72 [VII]78-86 Table 6-23

105 Malo’s Yard

From local reports this area was claimed to have been artiﬁcially constructed at a period in time unstated.

The particle size analysis showed an unusually high proportion of large-sized particles (4-2 mm) within the lower layers of the proﬁle, Layers V through VII. This matrix could be expected to develop from sediments transported in baskets as much of the smaller particles would fall out of the spaces between the weave of the basket leaving only the larger particles to remain. Fol- lowing this period in Layers II through IV the levels of small detritus drop signiﬁcantly and silt develops rapidly with a concomitant rise in organic matter.

The extraordinarily high numbers of Assiminea matches with deposits associated with the time of the copra industry. Deposits with these high numbers occur after the accumulations of large particle sizes, leading to the conclusion that the area was built up at, or shortly before, that time. Thus, it appears, that the area was built up for the purposes of creating more land to plant in copra showing that the island area was actively FIGURE 6-17: Malo’s Proﬁle increased to provide for economic growth. The analysis therefore supports the local reports and provides a time frame for its development.

106 FIGURE 6-18

Malo particle size 4-2 mm 70 2.0-0.5 mm 0.5-0.063 mm <0.063 mm

40 Malo’s yard: A

30 man-made 20 landform 10

0 [II] 10-20 [III] 24-34 [IV] 42-50 [V] 62-72 [VI] 84-94 [VII] 105-115

Table 6-24 Malo organic matter content moisture % organic % Nitrogen %

[II] 10-20 [III] 24-34 [IV] 42-50 [V] 62-72 [VI] 84-94 [VII] 105-115

Table 6-25

Malo snail terrestrial marine 450 Table 6-26 400

350

300

250

200

150

100

0 [II] 10-20 [III] 24-34 [IV] 42-50 [V] 62-72 [VI] 84-94 [VII] 105-115

107 FIGURE 6-19

Malo land snail Assiminea 250 Omphalotropis Allopeas 407 Subulina Lamellidea 200 Gastrocopta Liardetia Sturanya Truncatella

150

100

0 [II] 10-20 [III] 24-34 [IV] 42-50 [V] 62-72 [VI] 84-94 [VII] 105-115 Table 6-27

Malo marine snail R. balteata 80 R. sp T. granulata Trochidae 70 Epitoniidae other marine 60

0 [II] 10-20 [III] 24-34 [IV] 42-50 [V] 62-72 [VI] 84-94 [VII] 105-115 Table 6-28

108 Schoolyard

This area lay on the far end of the islet from the previous excavations and therefore gave a novel idea of what the environment was like on the other side of the village islet from all of the previously tested areas.

Signiﬁcant land snail numbers were only found in Layers I & III with distinct characteristics between the two. Layer I showed higher numbers of Assiminea and other introductions, while Layer III showed higher numbers of Omphalo- tropis and lower levels of late prehistoric introductions. In addition, Layer III contained the highest organic matter content measured in the study with a high percentage of silt FIGURE 6-20: Schoolyard Proﬁle development occurring at this time as well. At the time Layer III was deposited this area thus appears to have been left quite undisturbed with Omphalotropis favoring the more natural habitat. Layer II is a large deposit of coral that was probably purposefully laid across the area by people when the area was settled, no earlier than the late prehistoric. Layer I represents the deposition resulting from the occupation that followed. Local reports that this side of the islet was not settled until quite recently support this conclusion.

109 FIGURE 6-21

Schoolyard particle size 4-2 mm 60 2.0-0.5 mm 0.5-0.063 mm <0.063 mm

40 Schoolyard foundation: 30 Natural vegetation

0 [I] 5-22 [II] 68-70 [III] 71-78 [IV] 100-115 [FEA] 80-105

Table 6-29

Schoolyard organic matter content moisture % organic % Nitrogen %

[I] 5-22 [II] 68-70 [III] 71-78 [IV] 100-115 [FEA] 80-105

Table 6-30

School snail terrestrial marine 160 Table 6-31

140

120

100

0 [I] 5-22 [II] 68-70 [III] 71-78 [IV] 100-115 [FEA] 80-105

110 FIGURE 6-22

School land snail Assiminea 60 Omphalotropis Allopeas Subulina Lamellidea 50 Gastrocopta Liardetia Sturanya Truncatella 40

0 [I] 5-22 [II] 68-70 [III] 71-78 [IV] 100-115 [FEA] 80-105

Table 6-32

School marine snail R. balteata R. sp 6 T. granulata Trochidae Epitoniidae other marine 5

0 [I] 5-22 [II] 68-70 [III] 71-78 [IV] 100-115 [FEA] 80-105

Table 6-33

111 From the analysis of these three additional areas, a greater perspective can be obtained on the environmental changes that were occurring across the village islet throughout time. Progradation has been actively occurring to present with the most recent deposit on the southern-most edge of the islet within the past 100 years. This deposition is very similar to progradation that was occurring in the late prehistoric as exemplified in the lower layers of TU-4 and TU-8. Following re-settlement, the islet was actively being enlarged by the new inhabitants through the creation of coral- laden deposits as exhibited in the profile of Malo’s land and in the overlying coral layer outside the school. This development therefore included areas on the far side of the islet that had gone undisturbed for quite some time before. These modifica- tions to the islet were made to increase the land area for purposes of copra cultivation and population growth.

112 Conclusions

Thesis Summary

The past 150 years of geologic research has shown atolls to be complex geologic landforms that have undergone major changes over geologic time due to subsidence, the accumulation of marine sediments, submarine erosion, and sea level change. For many of these years debates were waged as to which of the forces predominated and it is only in recent times that the mutual influence of all these forces has been accepted. Perhaps the greatest force influencing the state of atolls though is sea level change. Accordingly it is only in the past two thousand years that a small drop in sea level of one to two meters due to the weight of glacial melt water resting on the flexing tectonic plates has caused the atolls of the Pacific to arise out of the water. The rapid spread of Polynesians across the Pacific at the beginning of this sea-level fall three thousand years ago has been noted by Roger Green and Bill Dickinson. This connection is based on the correlation of radiocarbon dates from early Polyne- sian sites throughout the Pacific and the dates of emerged paleoreef above the current high tide. While this evidence is sound enough to prove through indirect correlation it could be strengthened by direct evidence showing that Polynesians colonized low-lying atolls as soon as they emerged. Such evidence has been shown in the Marshalls where hearths dated to 1900 BP lay in sandy deposits from when the islands were no more than shifting sand cays and on Kapingamarangi where deposits directly atop the underlying paleoreef bedrock show that it was colonized even before deposition had occurred. This paper offers an additional method by dating the earliest appearance of commensal land snail species associated with initial settlement and plant introduction, following the examples of Marshall Weisler in Maloelap atoll.

The preferred habitat of land snails throughout their natural history has been moist upland forests, though many have adapted to live symbiotically within human garden systems. The presence of these species in deep deposits within the coral basement of atolls alongside pollen of upland forest plants have shown that these landforms were once well out of the water. Repeated ﬁndings within multiple layers of the same coral basement have shown that these species were capable of repeatedly colonizing the same distant Paciﬁc Island should the conditions prove favourable through

113 hurricanes and typhoons. The current state of these islands as low-lying atolls pre- vents the colonization of this group of land snails that favor upland forests because hurricanes and typhoons inundate the islands making colonization impossible. It is for this reason that the atolls of the Paciﬁc all contain a predominating atoll fauna composed of a different group of species favoring human garden systems. Accord- ingly all land snails present on low-lying atolls have been introduced through gardening activities. As settlement of any atoll would be accompanied by the introduction of food plants, the ﬁrst appearance of land snails associated with gardening activities would offer the earliest evidence of settlement as only the tiny land snail shells would survive. Subsequently any changes in the land snail fauna would represent new plant introductions and changes to the gardening systems. The initial appearance of land snails and there subsequent changes could then be compared to the soil development to show how gardening systems changed as the island developed over time.

The earliest archaeological projects on atolls were focused on the Polynesian outliers of Nukuoro, Ulithi, and Kapingamarangi all lying at the western extreme of Polynesia within the island groups exhibiting a typically Micronesian assemblage of artifacts, particularly those engaged within a trade network of pottery outside the western Polynesian region. These projects were focused foremost on answering questions on the relationship of these outliers to their Polynesian homeland such as the length of occupation and the degree of interaction versus isolation. The fact that these islands were atolls was only a secondary consideration and was initially seen as a potential difﬁculty to be overcome. It was believed that subsurface deposits would be rare on these islands due to the low-lying islands susceptibility to typhoons and their recent geology. The results of these project showed these assumptions to be false, however, and that subsurface deposits may be present on even the most heavily disturbed islands. In this paper it has been shown that far from being hindrances, typhoons and young geology provide an advantageous framework in which to con- struct scientiﬁc arguments about man’s role in these unique environments. The atoll environment takes on primary consideration as the major constructive variable that man purposefully manipulates to transform a harsh environment into an amiable one.

The preceding projects have found that people living on atolls actively build up the level of the island. The outer islets, that have undergone little artiﬁcial construction,

114 therefore remain low-lying with the natural forces of typhoons and the growth of vegetation taking great effect. However, on the village islets deep vertical deposition up to four meters thick has been found due to the activities of the people living there. At times this has accumulated at a rate of as much as a centimetre a year, such as on Kapingamarangi. It is here that cultural practices such as modern development and the recycling of materials take on greater impact than natural forces. This pattern encourages the inhabitants to remain on the single village islet and continue to build it up, so that special areas, such as the men’s and women’s house often remain in the same location over time making these areas easy to locate. The continual vertical deposition however does produce a multitude of discontinuous layers and banding that make stratigraphy difﬁcult to interpret and requires one to use artifact assemblages as proxies for relative dating. This paper offers methods for using commensal land snail species as proxies for relative dating to provide a clearer view of stratigraphic change and context for interpreting the artifacts found in those layers.

Botanical surveys of atolls have found the large majority of plants (59-65%) to be introductions with the dominant vegetation of coconut, pandanus, breadfruit, and pulaka all being Polynesian introductions. The native plants are all strand-line shrubs and later historical introductions are primarily weeds and ornamentals. It has been noted that the plant diversity falls into four zones moving from the shoreline to the center of the islets and is heavily inﬂuenced by the topography. The smaller, outer islets tend to be composed of a single zone of coconut and strand-line vegetation, with the larger, village islets composed of all four zones. These botanical surveys tend to focus on a synchronic viewpoint of the islands at present and have looked at how island size and rainfall differences affect vegetation and subsequently the potential for habitation. However, little attention has been given to the diachronic viewpoint of how islet size and topography have changed over time. Marshall Weisler’s work focused on a prehistoric perspective and thus began to look at a lengthier timeframe. Nevertheless, his project still takes a synchronic viewpoint of four islands at a single time period. What is needed is for a diachronic perspective to be taken of a single island.

Initially all atolls begin as strand-line environments dominated by a single zone. It is for this reason that all native plants on atolls are strand-line shrubs. It is only over time that soil develops and the more developed zones of plants form in the center of

115 the islet where the freshwater lens is greatest. It has been shown that village islets show the greatest deposition and soil development due to the activities of people. It is for this reason that the dominant vegetation is all Polynesian introductions because the Polynesians actively constructed the environment. Stone retaining walls intended to promote progradation and reduce erosion are proof of this active role and the correlation between deep vertical deposition and prehistoric occupation should not be assumed to be only a product of preservation. It is only after this soil development has undergone that weeds and ornamentals could be introduced in historic times. This paper looks more deeply at the development of the island over time and the role of people in that development.

Historical Ecology of Atafu Atoll

Land snail and soil analysis were chosen as the primary methods by which to answer the questions posed by the previous chapters, speciﬁcally, whether environmental modiﬁcation and gardening activity could be viewed in a diachronic perspective, which could act as a means for relative dating. The results showed that indeed one can.

The methods of this study were kept within the realm of what was possible in the field, while using additional laboratory tests to assess the accuracy and reliability of those field tests. Snail analysis, soil particle size analysis, and an analysis of the organic matter content were all found to be possible in the field through accurate and reliable means. The limited diversity of the atoll fauna allowed identification to be made in the field with only a limited amount of training. Using nested screens the samples could be divided into four particle size categories while extracting the snail material. Using a standard conventional oven, organic matter could be measured using soil moisture content as a proxy. The results of these three tests then allowed the sequence of changes common throughout the village islet to be divided into seven periods by which distinct areas could be aligned together.

Applying these methods to Atafu atoll in the Tokelau islands provided a general view of its historical ecology and conﬁrmed many of the claims reported by local informants. Prior to 600 BP the island was largely unaffected by people and therefore relatively unoccupied except for possible short-term visits. From roughly 650 to 550 BP settlement introduced some plants into the strand-line zone which would have

116 dominated the early environment. These early introductions did not measurably effect the island ecology. From roughly 550 to 450 BP additional plants were introduced with a slightly more pronounced effect on the environment along with an intensification of settlement. From roughly 450 to 300 BP the development of the non- strand zones is clear pre-empting the introduction of non-strand plants and a change in the kind of gardening activities. From roughly 300 to 100 BP the island was abandoned and re-colonized during which a significant amount of the forest was cleared of native growth and re-claimed for gardens as well as newly formed beach for habitation. From 100 BP to 0 BP garden activity intensified with the onset of the copra industry, during which time the inhabitants actively built more land mass to increase the economic potential of the island. From 0 BP to present additional plants were introduced from other regions through modern commerce. The dates applied to these period are rough estimations made from three radiocarbon dates, historical accounts, and speculation.

Closing Statements

Fosberg writes of the island ecosystem...

“It is probable that no island was ever completely stable. The limited size makes even relatively small changes capable of rather profound general effects; in other words, the buffering effects of great size and diversity are lacking. However, it is likely that, before the advent of man, many or most of the older island ecosystems had reached such relative stability that changes were mostly very slow. In most respects organisms present had evolved into and effective equilibrium with their environments. Closed biotic communities had developed that made difﬁcult the unaided invasion of new organisms.” (1963:5)

Atolls present one with a unique environment exceptional to Fosberg’s assessment. Their geology is so recent that no closed biotic community has had time to develop and the invasion of new organisms is of no difﬁculty if they are able to migrate to that environment. The colonization of people made that migration easy and so all species living within a syncretic relationship with man would be favored. This scenario creates a useful method by which to measure the settlement of man through those commensal species that came with that settlement within the gardens. More impor- tantly it means that the atoll is one of the few environments where man found a blank

117 slate in which to build an environment to best suit to habitation. Instead of being framed in a situation where man’s colonization leads to the destruction of the natural ecology, though this too can be seen on the ﬁner level, one is left with a situation where man creates an ecology through the creation of gardens.

Too often man’s effect on the environment is viewed purely as a negative, despite the fact that if it was not done we would not be here. The environment is always changing and understanding how it must be changed to allow human habitation is equally as important as understanding how to conserve the natural ecology. Atolls are composed almost entirely of introduced species and those capable of natural colonization have wide ranges of dispersal. Because of the high proportion of these introductions, atolls often draw little attention from ecologists purely interested in ‘natural’ ecology. Yet, the atoll ecology is made equally, if not more, complex by the disharmonic state created by frequent storms. This has led man to take a signiﬁcant role in conserving his environment through continuously re-planting gardens and introducing new plants as the atoll ecology changes with increases in land mass and soil development. It is hoped that the methods and theory discussed in this paper will lead to greater interest in the atoll ecology and how it changes over time, and that historical ecology will take on a signiﬁcant role in atoll archaeology.

118 Acknowledgements

Tokelau and the Paciﬁc

The creation of this paper has relied on the assistance, support, and opportunities given by many archaeologists, friends, and University departments. Primary amongst these, with the exception to family (though he too at times may be called family), is Dr. David Addison who provided the opportunity to work in Tokelau and collect samples for study and has provided materials and information from the project on Tokelau openly. It is with David that I first worked in the Pacific, and so long as there is a project in the Pacific that he is overseeing, I shall be there, unless asked to go home. I have been reminded more than once that I came perilously close to being sent home the first time we worked together. But this paper and our friendship serve as examples of what may come from perseverance and devotion to continuously im- proving oneself and respecting each other.

I must also acknowledge the co-director of the project in Tokelau, John Kalolo, who was the first of many Tokelauans to invite me into their home and provide more than the necessary amount of food. I first met John when first stepping onto the island from three days sailing from American Samoa. Bleary-headed I listened to him introduce me and my colleagues to the elders in moving, yet to me unintelligible Toke- lauan. Though I did not know what he said, I could see from the elders’ faces that he spoke good things and we have since been welcomed very warmly. This story leads me to Anne and Barry of the S/V Cat’s Paw who provided the free ride and sailing lessons which left me dazed and excited on the island at that time, and the many thanks I owe to Doctor Lameka for providing the newly completed wing of his beautiful house in the lagoon across from the pigs, or as we called it the Atafu Zoo. What a picturesque balcony on which to experience the wind that so characterizes Atafu during the sailing season. Doctor Lameka’s house was designed along a Western perspective and offered the usual comforts we had come to expect.

However, it was a great delight to live within a mdern Tokelau-style house with a To- kelau family and for this opportunity I must acknowledge Poni, Pua, ... who welcomed me as part of their family during the four weeks of the second season. In the semi-

119 traditional manner the house was open so that everyone slept and interacted together in a large lounge with the satellite television at the center. Such comforts can be known by neither the purely modernist or purely traditionalist and the merging of the two created a perfect anachronism that any archaeologist could appreciate. For this season, and the previous, I must also acknowledge the crew of the M/V Tokelau and the M/V Lady Naomi provided transport to and from the islands. There are three vessels that make regular trips to Tokelau, otherwise one must find their own, and so it is only through the work of the crews and captains of these ships that the project on Tokelau was possible. The three days sail aboard ship always framed our visit to To- kelau perfectly. It gave a sense of the voyages that the prehistoric visitors of Tokelau also would have taken and shared the spirit of the historic expeditions that first studied the Pacific from which our own study finds a foundation.

Finally, as concerns the people of Tokelau, I must acknowledge the tapulega, fatu- paipai, and aumaga the three institutions that oversee life on the island and ensure things remain peaceful each in their own way. I would like to acknowledge Dr. Rin- taro Ono with whom I spent much of the time during my two seasons on Atafu. Our time together provided many rich stories, which neither of us are allowed to tell in print.

And I must acknowledge Al and his family who provided me a home for the week I spent in Samoa prior to the trip in order to fulﬁll the required one-week quarantine to ensure that swine ﬂu was not spread to Tokelau. His home alongside the Palolo Deep marine reserve provided perfect access to splendid beach, town, and soulful music which plays regularly at the beginning and end of each day. I shall always stay with him whenever I am in Apia.

University assistance

I must begin this section by ﬁrst acknowledging my supervising professor, Dr. Glenn Summerhayes, who provided the most necessary assistance for the completion of this project which was a belief in its value and potential at the early stages of the work. If it were not for his support it is questionable whether the project would have been performed and completed so easily.

120 Phil Leatham, the lab manager for the anthropology department must also be acknowledged in this regard. I ﬁrst met Phil when at the airport at 3 am I was told an email from him was required to get my samples through Customs. I was thankful enough that he awoke to answer my phone call, but that he drove to the University and wrote the email and then met me at the department only a few hours later with such a friendly welcome says much about the quality of his person. Phil provided an open ear for many discussions that helped to wade through the ﬁner logistics of the project as did my fellow student, Nick Hogg.

At the beginning of the project I knew nothing of soil analysis and only heard about the Geography Lab through my flat-mate. I showed up at the lab with many questions much to the chagrin of the lab manager, Julie Clark. However, Julie provided access to all the equipment I needed with instruction on its use much the same as to any first-year novice though I really should have known better. It is through her assistance that I was able to gain experience testing particle sizes, organic matter, nitrogen and carbon content, soil moisture, soil pH, and all the intricate details of soil. I spent so much time in her lab that it must have been a great relief to see me finish.

It was Julie who informed me of the Horiba LA-950 particle size analyzer that the Pharmacy Department had newly acquired to measure their ﬁner powders. No one had yet to use it on soils and it is to his great merit that Mike Houghton, the lab manager, allowed an archaeologist to be the ﬁrst. Access to the equipment not only added to the data but gave me experience in a high-tech lab of more machines than I was willing to touch.

It also gave me the conﬁdence to seek permission to use equipment in other departments. Because of the minute size of the land snails a dissecting microscope with a camera attachment was needed and Grace Gardner and Fieke Neuman of the His- tology lab provided quick access to all that was needed providing the photographs by which the snails could be identiﬁed. When telling my friend Abe Gray of this he informed me of a microscope that could be used to illustrate my specimens as well. I must thank him and Marianne Miller of the Botany department for use of the microscope that provided the scale drawings of all the snails together.

Thus far all of these departments have been within the University of Otago where the bulk of the lab research, literature review, and thesis writing were performed. There

121 were however members of additional universities involved that I must acknowledge. Foremost of these was Dr. Carl Christensen, a malacologist and law professor at the University of Hawaii at Manoa, who has worked with many Pacific archaeologist and who was in the process of working with many others when I first met him. He took time from many other projects though to instruct me on the finer points of identifying Pacific land snails and confirmed all the identifications made in this paper via emailed photographs, a difficult and unsettling task in a science that depends on fine detail, but one for which I have complete confidence in his accuracy.

I must also acknowledge Dr. Robert Bollt, also of the University of Hawaii at Manoa, who ﬁrst introduced me to land snail analysis at the end of 2007 during an excavation at the Atiahara site on the island of Tubuai. Rob constructed a specially made screen for the extraction of land snails and I watched him curiously as he went about collecting samples to send to Carl. It is only because of this experience that I ﬁrst suggested to David that land snail analysis could be possible on Tokelau. Rest in Peace, Rob.

I would also like to thank my friend Jeff Putzi, a Hawaiian archaeologist for many years who provided continual support to complete my thesis so that I could one day work again with him. Equally valuable was the support of Jen Heubert of the Univer- sity of Auckland who also performed the charcoal identiﬁcation on specimens from my column samples and whom I look forward to working with on the subject much more in the future.

I must also acknowledge the University of Texas libraries whose books were the ﬁrst to be researched before I returned to New Zealand.

122 Family & friends

“The man who agrees with us that some question, little regarded by others, is of great importance, can be our Friend. He need not agree with us about the answer.” C.S. Lewis

According to the quote above all those listed before may be counted as my friends. However, a few must be acknowledged by their exceptional friendship. My friend Rebecca Kinaston graciously took care of my stuff while I was away from New Zea- land in the ﬁeld and abroad for 18 months as well as a house to stay in during part of my academic career. My girlfriend, Kajsa Louw, was always patient and understanding of my other commitments. My sister, who though she might not express it so lib- erally, most deﬁnitely thinks archaeology is as cool as horse-riding. And my Mom and Dad who have always supported whatever path I have chosen no matter how distant the land to which it leads.

Thank You.

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140 Appendix A: An assessment of the reliability of the land snail ﬁeld test

To assess the reliability and accuracy of the 250 gram sample for the land snail analysis two samples were run in the expectation that both samples should provide the same results. Oftentimes the second of these samples came up a little under 250 grams and so it was not unexpected that the second sample should be a little less than the first. Overall though the results proved to be similar enough to say that 250 grams is a proper sample for the field test. Where there was a large count of a particular specimen larger error did occur but this would not be expected to alter the interpretation of the data in any significant way. Where there was a low count, of only one or two, for a particular specimen, there was the possibility that none would be seen in the other test. Therefore tests that produce such low counts may be considered of lesser interpretative value. All other counts were found to produce identical interpretations of the data. Samples not included contained insufficient material.

Table A-1: Comparative Results of Land Snail Analysis, TU-4 & TU-8

Table A-2: Comparative Results of Land Snail Analysis, 100YR

141 Table A-3: Comparative Results of Land Snail Analysis, MALO

Table A-4: Comparative Results of Land Snail Analysis, TU-2

Table A-5: Comparative Results of Land Snail Analysis, SCHOOL

142 Appendix B: An assessment of the reliability of the soil particle size ﬁeld test

To assess the reliability of the particle size field test, the test was repeated on an identical sample of 250 grams simultaneous with the land snail extraction. Results for the larger four categories of particle sizes (small detritus, coarse sand, find sand, and silt) were found to be identical with only a few percentage points of difference. Results for the more defined groups within the fine sand category were found, however not to replicate with a high degree of difference between the two tests. There- fore, only the results for the larger categories have been included in the study.

Table B-1: Comparative Results of Particle Size Field Test, TU-2

143 Table B-2: Comparative Results of Particle Size Field Test, TU-4

Table B-3: Comparative Results of Particle Size Field Test, TU-8

144 Table B-4: Comparative Results of Particle Size Field Test, 100YR

Table B-5: Comparative Results of Particle Size Field Test, MALO

145 Table B-6: Comparative Results of Particle Size Field Test, SCHOOL

146 Appendix C: Results of the Horiba LA-950 laser diffraction particle size test

In addition to the ﬁeld test whereby particle size was measured by forcing the sample through nested screens and weighing the contents, a lab test was performed with the use of a machine newly acquired by the University of Otago pharmacy laboratory. The Horiba LA-950 measures the quantities of different particle sizes from 0.01 to 3000 microns within each sample.

Each sample was put through a 2 mm screen so that all measurements should be below 2000 microns. Any measurements above this threshold would then provide evidence of clumping within the sample which was mediated by ultrasonic agitation. Peaks between 500 and 2000 microns would show quantities of coarse sand, between 63 and 500 microns would show quantities of ﬁne sand, and between 1 and 63 microns would show quantities of silt, as shown below...

FIGURE C-1: Example of Horiba LA-950 Data Graph Interpretation

These findings were then compared to the findings of the field test using the nested sieves. Though, slight differences in individual results may be attributed to user error, the overall pattern in all measurements was found to be the same. Thus the accuracy of both tests is good.

The reliability of the ﬁeld test was measured by performing the test twice on the same sample so that the same measurement should be made on each. For the larger

147 categories of silt, fine sand, and coarse sand the measurements were found regularly to be within only a few percentage points. The more precise measurements for the fine sand particles was, however, found to regularly differ by a significant amount and to be unreliable.

148 FIGURE C-2

TU-2 Horiba Data

! ! ! ! ! sample [14]!! ! ! ! ! ! sample [18] ! ! ! 0-8 cmbs! ! ! ! ! ! ! 58-68 cmbs ! ! ! sandy modern topsoil! ! ! ! ! cultural

! ! ! ! ! sample [15]!! ! ! ! ! ! sample [19] ! ! ! 10-17 cmbs!! ! ! ! ! ! 78-92 cmbs ! ! ! light beach sand! ! ! ! ! ! cultural

! ! ! ! ! sample [16]!! ! ! ! ! ! sample [20] ! ! ! 19-26 cmbs!! ! ! ! ! ! 100-110 cmbs ! ! ! ﬁne loam! ! ! ! ! ! ! gray cultural

! ! ! ! ! sample [17]!! ! ! ! ! ! sample [21] ! ! ! 30-37 cmbs!! ! ! ! ! ! 110 120 cmbs ! ! ! loamy sand!! ! ! ! ! ! gray sand

! ! ] ! ! ! sample [23]!! ! ! ! ! ! sample [22] ! ! ! 45-52 cmbs!! ! ! ! ! ! 130-148 cmbs ! ! ! coral lens! ! ! ! ! ! ! beach sand !

149 FIGURE C-3

TU-4 Horiba Data

! sample [8] ! 20-26 cmbs ! burial pit

! sample [9] ! 46-54 cmbs ! dark cultural

! sample [11] ! 70-74 cmbs ! coral & sand

! sample [12] ! 90-98 cmbs ! gray sand

150 FIGURE C-4

TU-8 Horiba Data

! ! sample [1] ! ! 4-8 cmbs ! ! modern topsoil

! ! sample [2] ! ! 11-15 cmbs ! ! sand

! ! sample [3] ! ! 22-32 cmbs ! ! dark coral

! ! sample [4] ! ! 42-48 cmbs ! ! cultural

! ! sample [5] ! ! 55-65 cmbs ! ! gray sand

! ! sample [6] ! ! 90-100 cmbs ! ! beach sand !

151 FIGURE C-5

100 YR Horiba Data

! ! ! ! ! sample [24]!! ! ! ! ! ! sample [29] ! ! ! 0-5 cmbs! ! ! ! ! ! ! 38-46 cmbs ! ! ! light gray sand! ! ! ! ! ! beach sand & coral

! ! ! ! ! sample [25]!! ! ! ! ! ! sample [30] ! ! ! 5-10 cmbs! ! ! ! ! ! ! 50-57 cmbs ! ! ! dark gray sand! ! ! ! ! ! cultural

! ! ! ! ! sample [26]!! ! ! ! ! ! sample [31] ! ! ! 10-20 cmbs!! ! ! ! ! ! 60-66 cmbs ! ! ! loose coral! ! ! ! ! ! ! ﬁne light gray sand

! ! ! ! ! sample [27]!! ! ! ! ! ! sample [32] ! ! ! 20-25 cmbs!! ! ! ! ! ! 68-72 cmbs ! ! ! beach sand!! ! ! ! ! ! light gray sand

! ! ! ! ! sample [28]!! ! ! ! ! ! sample [33] ! ! ! 28-34 cmbs!! ! ! ! ! ! 78-86 cmbs ! ! ! dark gray lens! ! ! ! ! ! beach sand !

152 FIGURE C-6

Schoolyard Horiba Data

! sample [40] ! 5-22 cmbs ! modern topsoil

! sample [41] ! 68-70 cmbs ! compact sand

! sample [42] ! 71-78 cmbs ! black cultural

! sample [43] ! 100-115 cmbs ! brown soil

! sample [44] ! 80-105 cmbs ! posthole

153 FIGURE C-7

Malo Horiba Data

! ! sample [34] ! ! 10-20 cmbs ! ! dark cultural

! ! sample [35] ! ! 24-34 cmbs ! ! cultural

! ! sample [36] ! ! 42-50 cmbs ! ! cultural & coral

! ! sample [37] ! ! 62-72 cmbs ! ! loose coral

! ! sample [38] ! ! 84-94 cmbs ! ! gray sand & ! ! coral

! ! sample [39] ! ! 105-115 cmbs ! ! beach sand

154 Appendix D: Pulaka Pit Test Core

During the 2009 ﬁeld season a test core was taken from a recently made pulaka (swamp taro, Cyrtosperma) pit using a one-meter length piece of 6-inch wide PVC piping. The extraction of the core destroyed the piping in the process but success- fully removed a single core intact. As the purposes of this test was for a pilot study to assess whether any distinct characteristics could be applied to areas of pulaka cultivation, the single core was believed to be sufﬁcient at the time.

A unique snail type was seen within this core of the family Thiaridae, a terrestrial snail that prefers brackish water. It is most likely Thiara (Tarebia) granifera or Melanoides tubercularta. Due to the recent nature of the pulaka pit, a lack of data in the literature, and the fact that only a single core was taken, the period in which this species would have been introduced to Tokelau can not be assessed at this time. However, the results are promising that future studies may identify a snail specific to prehistoric pulaka cultivation by which the development of such cultivation practices may be measured over time. At present, studies have focused on this subject by identifying spoil heaps associated with pit FIGURE D-1: Pulaka Snail cultivation and dating the underlying buried A horizon (Weisler 1999; Yamaguchi et al 2009). Identifying snail species associated with distinct introductions and periods of agriculture intensification would add significantly to these studies.

A related species of snail, Melanoides arthurii, was reported from the Southern Cook Islands (Craig 1995) and was reported to be widespread through Fiji, Samoa, Tonga, Tahiti, and the Cook Islands, where it is found in fresh water ponds and taro swamps. Such common occurrence makes the identiﬁcation of these snails in future studies highly likely.

155 FIGURE D-2

Table D-1: Results from the Pulaka Pit Test Core

156 Appendix E: XRF testing

Pisonia forests on outer islets hint at a possible pre-human forest type. These areas have been left for bird nesting as birds have been very important for ﬁshing throughout time and important in locating the island at sea in prehistory. Pisonia is the only native not spread by wind or ocean currents; its fruits adhere to the feathers of wide- ranging sea-birds (Hatheway 1953:4). Consolidated phosphatic limestone was found to be restricted to areas where Pisonia was the primary species. This phosphatic hardpan is due to the high prevalence of ﬁsh-eating terns in Pisonia forests and was found to preserve the water table (Hatheway 1953:57-8). Atolls with a long natural history of Pisonia forests would therefore provide ready-made gardens for man to colonize.

“The substitution of coconut plantations for natural forest growth over much or most of the land surface on atolls with sufficient moisture has been man’s most outstanding effect upon atoll and reef island vegetation patterns” (Wiens 1962:456). The extraction of trees could have caused increases in erosion and the displacement of birds leading to the eventual loss of initial fertility. This process was further stimulated during European contact, particularly with the Germans, by which a burgeoning copra trade was spread throughout the Pacific giving an additional economic benefit to forest destruction for purposes of coconut cultivation. In contrast, the modern handicraft trade has stimulated the production of pandanus for the making of mats.

Despite the lengthy period of forest modiﬁcation residual levels of this phosphate hardpan may still remain providing evidence of areas characterized by substantial levels of soil fertility in prehistory and today. At present, on Atafu atoll, kanava trees (Cordia subcordata) grow straighter and larger than on any other atoll in the Tokelau islands and are unique among specimens of Cordia found on other islands (Gal- lagher, personal communication). It is not surprising then that local informants claim that all the canoes in Tokelau were made from the kanava grown on Atafu. The presence of high levels of phosphates could explain why these trees have grown so tall and straight. Its absence would exemplify an extraordinary instance of selective breeding. In either case, an elemental analysis of micro-nutrients within the soil would give greater detail to the soil analysis performed in this study. It is therefore

157 recommended that a tests be performed on all soil samples by X-ray Fluorescence (XRF) to measure the quantities of phosphorous and other micro-nutrient elements such as Magnesium.

158 Appendix F: Preliminary charcoal identiﬁcation

Charcoal fragments from the larger of the five screens ranging from 4 to 2 mm in size were separated and sent to Jen Huebert, MA of the University of Auckland for a preliminary identification to assess the value of such a test in future studies. The results of this pilot study found the size of the samples to be below the customary size for charcoal identification of 4 mm. Future studies will therefore focus on collecting samples between 4-6 mm. Nevertheless, a rough qualitative study was able to be performed. Coconut and a variety of native scrub plants were found to be the most common, along with an unidentified tree that may be Pisonia. A reference collection specific to the tropical Pacific atoll environment, preferably specific to the Tokelau archipelago, will be needed if a more defined study is intended. The results of this pilot study do suggest that a more carefully developed quantitative study could be performed that would compare the quantities of coconut and other introduced wood species such as breadfruit, to the native scrub plants and Pisonia which could assess the role of human modification in the environment. Higher numbers of native scrub plants and Pisonia would suggest a more natural, unaltered environment, while higher numbers of coconut and breadfruit would suggest greater human modification. Changes in these ratios over time could provide a diachronic perspective to compare to the data set from the tests described within this paper. Charcoal identification shall therefore be incorporated in the future studies on the other atolls of Tokelau in addition to the land snail and soil analyses.

159