A trans-holocene approach to assess maritime development on the California Channel Islands archipelago: A case study from Eel Point, San Clemente island

Abstract

The Channel Islands of California have received much attention from researchers, in part, due to the long occupation history of the islands that spans at least 13,000 years. The Northern Channel Islands have played an important role in our understanding of early coastal adaptations and development of complexity among maritime adapted peoples; however, this is only part of the picture. The Southern Channel Islands, located approximately 90 km south of the Northern Channel Islands, have a similar occupational history to their northern counterparts, but exist in a very different environmental and geographic context. Occupants on each island would have faced marine and terrestrial environments that could be vastly different based on issues such as fluctuating sea temperatures, fresh water accessibility, and plant, animal, and marine shell seasonality. The coastal adaptations along all the Channel Islands reflected these differences. Understanding variation on the Channel Islands archipelago can be realized by comparing and contrasting multiple types of environmental and material data from trans-Holocene sites, archaeological deposits that present continuous data sequences over a wide time span of the Holocene. One such site from San Clemente Island in the southern portion of the archipelago is Eel Point. Previous excavations at this site resulted in a rich array of cultural material; however, recent research has shown major portions of the collections have not yet been processed, are unanalyzed, or are under-analyzed. Specifically the groundstone and archaeobotanical assemblages have not been comprehensively analyzed or reported on, but are integral to understanding not only subsistence strategies, but also technological development and island paleo and historical ecology. These data form the basis for an inter-island comparative approach to understand long-term human-environmental interactions and impacts to ancient ecosystems on the Channel Islands archipelago. This study focuses on leveraging these under-analyzed and unanalyzed data to present on the variation in adaptions on the archipelago and to demonstrate the relevance of multi-island studies for considering the cultural impacts of climatic change in Mediterranean environments.

Introduction

Over the past few decades, numerous archaeological investigations on the Channel Islands of California have contributed to theoretical insights on the development of maritime societies and human adaptations to environmental fluctuations in Mediterranean environments (inter alia, Arnold, 1992, 2001; Braje, 2010; Braje et al., 2012, 2017; Byrd and Whitaker, 2015; Erlandson et al., 2011; Gamble, 2008; Gill et al., 2019a; Glassow et al., 2008; Gusick, 2012, 2013; Kennett, 2005; Rick et al., 2005; Raab et al., 2009; Pletka, 2001; Teeter et al., 2013). These studies have increased our understanding of the development of maritime hunter-gatherer-fisher cultures in the North Pacific and have contributed to the anthropological literature on the antiquity and unique nature of maritime cultures more broadly. They also inform resource management decisions on the Channel Islands and demonstrate the global relevance of a historical ecological framework and resulting trans-Holocene data from the islands. Yet, much of this research has not focused on an archipelago-wide approach. Research originating on the California Channel Islands tends to focus on the Northern Channel Islands, and the Island Chumash who have long resided there, and to a lesser extent the Southern Channel Islands, and the Island Tongva people. Further, because of differences in land ownership and logistics, among other important reasons, not all of the eight islands have received comparable archaeological attention and few islands have been thoroughly surveyed. This has resulted in an overemphasis on the Northern Channel Islands and the Island Chumash in our characterization of maritime societies and ecological shifts through time along this region of the Pacific Rim. This is problematic as there is significant environmental variation between the landmasses in the Channel Islands archipelago and adaptation strategies were likely tailored to individual ecological regions contributing to the development of unique Chumash and Tongva cultures (Gusick, 2012; Jazwa and Perry, 2013; Kennett, 2005; Raab et al., 1994, 2009; Rick et al., 2005).

The human-environmental adaptations to local ecosystems that occurred on the Channel Islands archipelago over the last 15,000 years are significant from a global perspective. This archipelago is in one of the five world regions with Mediterranean-type ecosystems - California, Central Chile, the Mediterranean Basin, the Cape Region of South Africa, and Southwestern and South Australia. These regions cover only about 2% of the world's landmass, but the combined vascular plant species comprise 20% of the world's flora (Esler et al., 2018). The marine ecosystems within these regions also tend to be rich, making them ecological “hot spots” that have long been attractive for human habitation. Evidence from the central Aegean suggests this region in the Mediterranean Basin was inhabited at least 200,000 years ago by Neanderthal and earlier humans (Carter et al., 2019); Blombos Cave in the Cape region of South Africa boasts one of the longest coastal occupations of homo sapiens worldwide, beginning about 100,000 years ago (Henshilwood et al., 2011); and, the Channel Islands of California harbor evidence of some of the earliest human occupations in the Americas, beginning during the terminal Pleistocene (Johnson et al., 2002; Erlandson et al., 2011). Each of these regions boasts early regional occupation and in some cases provides evidence for early human development and adaptations such as symbolism and seafaring. Although limited in geographic area, these regions are ideal for global comparisons that consider not only their similarities, but also the sometimes subtle differences that played a major role in biological adaptations of both plant and animals species. The sustained human habitation that continues today in these regions provides a deep time lens to consider long term human impacts to Mediterranean environments that helps inform modern conservation and management practices of these unique regions.

Considering the unique and outsized impact that Mediterranean-type ecosystems have on biological and human development, it is integral to consider the role even slight ecological variations may have played in the development process. The four Southern Channel Islands, located approximately 90 km south of the Northern Channel Islands, have a similar occupational history to their four northern counterparts, but exist in a different environmental and geographic context. Generally, the southern islands are warmer, more arid, and separated by longer oceanic distances. In this context, the coastal adaptations that are understood from the Northern Channel Islands may have differed substantially on the Southern Channel Islands. The long occupational sequence known from both groups of islands provide researchers the ability to present a different perspective on coastal adaptations in Mediterranean ecosystems and the dynamic relationship between people, island environments, and climate change through time. Data used to understand these long-term cultural and ecological trends are sometimes aggregate, coming from a variety of sites that date to discrete or shorter periods of time (i.e., Braje et al., 2009, 2012; Byrd and Whitaker, 2015; Erlandson et al., 2005, 2008, 2011; Kennett, 2005; Perry, 2004a; Perry and Glassow, 2015; Raab et al., 1994; Yatsko, 2000). While this approach is useful, a trans-Holocene occupational sequence from a single site provides an opportunity to explore continuous data, originating from a single location where diachronic trends in local habitats can be identified and compared to local cultural sequences. Comparing trans-Holocene sequences from multiple single sites located across a region encourages development of a broad theoretical framework that recognizes regional change in society and ecology while forming the foundation to understand these changes on a local level. These local trends are integral to characterizing adaptation strategies that influence cultural developments, creating unique maritime societies dependent on local environmental variants (Koyama and Uchiyama, 2002).

Among the cultural resources identified on the Channel Islands, there are numerous trans-Holocene sites that have been the subject of study over the past 50 years. On the southern islands, Little Harbor (CA-SCAI-17) on Catalina Island and Eel Point (CA-SCLI-43) on San Clemente Island have had sustained large-scale excavations over decades; however, recent research has shown major portions of both collections have not yet been processed, are unanalyzed, or are under-analyzed. Unanalyzed and under-analyzed archaeological assemblages are problematic and point to the lack of societal investment in systematic collection and curation activities (Morrison et al., 2018), a situation that contributes to the curation crisis (Bawaya, 2007; Bustard, 2000). Additionally, the majority of the material analyses that have been conducted on the site assemblages were done almost two decades ago, and a reanalysis can use materials to address research issues that may not have been originally considered (Morrison et al., 2018; Voss, 2012). For instance, original analyses were unable to benefit from recent updates in our understanding of regional environmental and cultural changes, or from a paradigm shift in how underlying assumptions of island marginality have impacted suspected drivers of political-social complexity (i.e., Jazwa and Perry, 2013; Gill et al., 2019a). The outdated analyses and the unanalyzed and under-analyzed assemblages are problematic for characterizing maritime adaptations on the southern islands. New analyses of the existing collections are necessary to incorporate new data and new ideas into the discussion of long-term adaptive change and development of maritime societies in the Southern California Bight, and in Mediterranean environments more broadly.

While collection analysis from trans-Holocene sites across all of the Channel Islands is ongoing, here we focus on the 9000-year-old trans-Holocene Eel Point site on San Clemente Island. Overall, the chronological, subsistence, and settlement data previously recovered from Eel Point, and other sites on San Clemente Island, question traditional models of maritime cultural development in coastal Southern California (Cassidy et al., 2004). During years of archaeological excavation and data collection starting in the 1950s (Meighan, 2000; Raab et al., 2009; McKusick and Warren, 1959), there was a focus on particular artifact and faunal types at the expense of other portions of the assemblage. Groundstone and paleoethnobotanical assemblages, for instance, have been largely overlooked compared to chipped stone and marine fauna. These largely overlooked aspects of the collection can now be reevaluated in the context of updated ecological data and archaeological methodologies.

Recently, perceptions of marginality and marginal environments have been reconsidered in different island contexts globally (Bebermeier et al., 2016; Fitzpatrick et al., 2016), including the Channel Islands archipelago (Rick et al., 2013; Perry et al., 2019; Gill et al., 2019a). Previously considered resource-poor or marginal compared to other islands in the archipelago (Yatsko, 2000), the archaeological record of San Clemente Island provides an opportunity to consider the multitude of adaptive strategies practiced by maritime peoples in variable environmental and geographic contexts. Employing a trans-Holocene and comparative regional approach that addresses important gaps, will allow for meaningful comparisons between islands (Kirch, 2007; Vitousek, 2002) to identify fundamental variables influencing cultural development in Mediterranean environments.