The human-mediated movement of species across biogeographic boundaries—whether intentional or accidental—is dramatically reshaping the modern world. Yet humans have been reshaping ecosystems and translocating species for millennia, and acknowledging the deeper roots of these phenomena is important for contextualizing present-day biodiversity loss, ecosystem functioning and management needs. Here, we present the first database of terrestrial vertebrate species introductions spanning the entire anthropogenic history of a system: the Caribbean. We employ this approximately 7000-year dataset to assess the roles of historical contingency and priority effects in shaping present-day community structure and conservation outcomes, finding that serial human colonization events contributed to habitat modifications and species extinctions that shaped the trajectories of subsequent species introductions by other human groups. We contextualized spatial and temporal patterns of species introductions within cultural practices and population histories of Indigenous, colonial and modern human societies, and show that the taxonomic and biogeographic diversity of introduced species reflects diversifying reasons for species introductions through time. Recognition of the complex social and economic structures across the 7000-year human history of the Caribbean provides the necessary context for interpreting the formation of an Anthropocene biota.

17The human-mediated movement of species across biogeographic boundaries-whether 18 intentional or accidental-is dramatically reshaping the modern world. Yet, humans have been 19 reshaping ecosystems and translocating species for millennia, and acknowledging the deeper 20 roots of these phenomena is important for contextualizing present-day biodiversity loss, 21 ecosystem functioning, and management needs. Here, we present the first database of terrestrial 22 vertebrate species introductions spanning the entire anthropogenic history of a system: the 23 Caribbean. We employ this ~7,000 year dataset to assess the roles of historical contingency and 24 priority effects in shaping present-day community structure and conservation outcomes, finding 25 that serial human colonization events contributed to habitat modifications and species extinctions 26 that shaped the trajectories of subsequent species introductions by other human groups. We 27 contextualized spatial and temporal patterns of species introductions within cultural practices and 28 population histories of Indigenous, colonial, and modern human societies, and show that the 29 taxonomic and biogeographic diversity of introduced species reflects diversifying reasons for 30 species introductions through time. Recognition of the complex social and economic structures 31 across the 7,000-year human history of the Caribbean provides the necessary context for 32 interpreting the formation of an Anthropocene biota. 33 34 Caribbean archaeology 36 37 38 39 A wide range of disciplines continue to debate the origin and defining characteristics of 40 the Anthropocene [1]. Yet, an undeniable signal of global human impact is the formation of 41 novel ecosystems and non-analogue assemblages, which have been created by the intentional and 42 accidental movement of species outside their native ranges in the context of land use change and 43 selective extinctions [2]. Human-mediated species translocations have fundamentally changed 44 the planet's biogeographic assembly rules by eroding the barriers separating islands, continents, 45 and hemispheres [3]. This reshaping of species ranges is not unique to present day human 46 societies: today's introduced species are part of a much longer legacy, with the earliest 47 documented translocation occurring approximately 20,000 years ago [4]. Since this Late 48 Pleistocene beginning, the advent of agricultural domestication and advancement of maritime 49 technology vastly increased the number of translocations and the geographic distance of the 50 translocation in the Holocene [5], and subsequently, colonial trade, industrial shipping, and the 51 wide-ranging effects of globalization have generated the Anthropocene biota that define our 52 modern landscapes [6]. 53 The ecological and economic impacts of such translocated species today are intensively 54 studied in management contexts, but whether and how the long-term (millennial-scale) sequence 55 of human-mediated species introductions have hindered or promoted subsequent introd...