Conservation of species and ecosystems is increasingly difficult because anthropogenic impacts are pervasive and accelerating. Under this rapid global change, maximizing conservation success requires a paradigm shift from maintaining ecosystems in idealized past states toward facilitating their adaptive and functional capacities, even as species ebb and flow individually. Developing effective strategies under this new paradigm will require deeper understanding of the long-term dynamics that govern ecosystem persistence and reconciliation of conflicts among approaches to conserving historical versus novel ecosystems. Integrating emerging information from conservation biology, paleobiology, and the Earth sciences is an important step forward on the path to success. Maintaining nature in all its aspects will also entail immediately addressing the overarching threats of growing human population, overconsumption, pollution, and climate change.

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.

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Aim Intrinsic qualities that might affect extinction risk are not well understood for lizards (suborder Lacertilia), a highly diverse and globally distributed group of reptiles (order Squamata). We use the Quaternary fossil record of Caribbean lizards to explore a commonly studied trait, body size, and its relationship to extinction. Location The Caribbean. Methods We compiled a body size database for over 300 species. We assessed whether the present‐day body size distribution of lizards differed from the body size distribution of the fossil record. We also compared body sizes of extant lizards with extinct lizards, and we used the International Union for Conservation of Nature (IUCN) Red List to evaluate whether threatened species are larger than non‐threatened species. We examined whether there were geographic or phylogenetic biases to extinction in this system. Results Quaternary extinctions were size‐biased, with a higher incidence of extinction in large‐bodied lizards; the same relationship exists between threatened and non‐threatened present‐day lizards. Biases in the fossil record do not drive this trend, as the body sizes of present‐day lizards do not differ from those preserved in the fossil record. While there is no geographic variability in extinction, we find that there is lineage specificity, as the majority of extinctions occur within the family Leiocephalidae. At the family level, size alone does not explain extinction trends for most families, but our data suggest that large‐bodied species in each family have a higher extinction risk than their smaller counterparts. Main conclusions Size‐biased extinction trends in lizards mirror phenomena in other taxonomic groups, but additional life‐history traits may play a role at the family level. We highlight the utility of fossil datasets in understanding extinction dynamics and underscore the urgency of a thorough assessment of extinction risk for insular lizards.

SCIENCE sciencemag.org mutual respect can the Americas write a new playbook that fulfills the often stated but seldom realized ideals of equality for all.