Tropical islands of the Anthropocene: Deep histories of anthropogenic terrestrial-marine entanglement in the Pacific and Caribbean

Differences in Subtidal Macrobenthic Community Structures and Influencing Factors Between Jindo and Jeju Islands in South Korea

Although islands in South Korea have been significantly impacted by human activities, marine ecological studies focusing on island coasts have been limited. Due to their distinct characteristics, macrobenthos is extensively utilized to assess the impact of anthropogenic influences on the marine environment. In August 2010, August 2011, and September 2012, samples of macrobenthic communities, bottom water, and sediment were collected from the subtidal zones around southern Jindo and northern Jeju islands in South Korea. Macrobenthos was identified to the species level using a stereomicroscope. Bottom seawater quality was evaluated, with a focus on dissolved heavy metal concentrations (As, Cr, Cd, Cu, Pb, and Zn). Additionally, we measured the organic matter content and mean grain size of the sediment. There were marked differences in macrobenthic community structures between the two islands, including the number of species, species abundance, species richness index, and Pielou's evenness index (p < 0.05). Cluster analysis, non-metric analysis, permutational multivariate analysis of variance (PERMANOVA), and permutational analysis of multivariate dispersion (PERMDISP) revealed variations in macrobenthic communities between the two islands and over the years 2010, 2011, and 2012. According to the Biota-Environment Matching (BIO-ENV), distance-based redundancy analysis (dbRDA), and distance-based linear model analyses (DistLM), the principal environmental variables influencing the distribution of macrobenthic communities are Cd and As. These variations likely result from different levels of human activity on each island. Moreover, interannual variations in macrobenthic communities, especially in 2012, were predominantly influenced by Pb and Cr, likely due to alterations in the influence of the Changjiang (Yangtze River) diluted water.

Enhancing biodiversity: historical ecology and biogeography of the Santa Catalina Island ground squirrel, Otospermophilus beecheyi nesioticus

People have influenced Earth's biodiversity for millennia, including numerous introductions of domestic and wild species to islands. Here, we explore the origins and ecology of the Santa Catalina Island ground squirrel (SCIGS; Otospermophilus beecheyi nesioticus), one of only five endemic terrestrial mammals found on California's Santa Catalina Island. We synthesized all records of archaeological/palaeontological SCIGS, conducted radiocarbon dating and stable isotope analysis of the potentially earliest SCIGS remains and performed genetic analysis of modern SCIGS. Squirrels were not identified in island palaeontological deposits, but at least 12 island archaeological sites contain SCIGS bones, including some that are butchered or burned. All directly dated SCIGS bones are Late Holocene in age and younger than approximately 1290 cal BP. The first mitochondrial genome for modern Otospermophilus beecheyi and 15 modern SCIGS mitogenomes document at least one introduction of squirrels. Stable isotope data indicate variable SCIGS diets and potential subsidies from marine environments to terrestrial plants consumed by some individuals. We cannot rule out a natural overwater dispersal, but the earliest SCIGS remains post-date the earliest evidence for people by several millennia and, along with other lines of evidence, support a human-assisted translocation of squirrels during the Late Holocene. These data illustrate the important role of Indigenous people in shaping and enhancing island biodiversity and ecology around the world.

Archaeological evidence of resource utilisation of the great whales over the past two millennia: A systematic review protocol

Archaeological faunal remains provide key insights into human societies in the past, alongside information on previous resource utilisation and exploitation of wildlife populations. The great whales (Mysticete and sperm whales) were hunted unsustainably throughout the 16th - 20th centuries (herein defined as the modern period) leading to large population declines and variable recovery patterns among species. Humans have utilised whales as a resource through carcass scavenging for millennia; however, increasing local and regional ethnographic and archaeological evidence suggests that, prior to the modern period, hunting of the great whales was more common than previously thought; impacts of earlier hunting pressures on the population ecology of many whale species remains relatively unknown. Hunting guided by traditional ecological knowledge may have been sustainable and likely originated in societies that also incorporated opportunistic use of stranded individuals. The collation of georeferenced zooarchaeological data of the great whales between the 1st - 20th centuries CE worldwide will provide insight into the timescale and distribution of resource utilisation of the great whales and how this varied within and between societies, and may have changed over time. By comparing regions of known resource utilisation and breeding and feeding grounds of current-day whale populations, this information will subsequently be used to infer regions where whale populations were possibly lost or extirpated prior to detailed historical records. This systematic review protocol also provides a template for archaeologists, ecologists, and historians interested in using faunal remains to infer historical ecology and resource use of wild animal populations. The transparency of our data collection approach provides opportunities for reproducibility and comparability with future datasets.

Harnessing island-ocean connections to maximize marine benefits of island conservation

Islands support unique plants, animals, and human societies found nowhere else on the Earth. Local and global stressors threaten the persistence of island ecosystems, with invasive species being among the most damaging, yet solvable, stressors. While the threat of invasive terrestrial mammals on island flora and fauna is well recognized, recent studies have begun to illustrate their extended and destructive impacts on adjacent marine environments. Eradication of invasive mammals and restoration of native biota are promising tools to address both island and ocean management goals. The magnitude of the marine benefits of island restoration, however, is unlikely to be consistent across the globe. We propose a list of six environmental characteristics most likely to affect the strength of land-sea linkages: precipitation, elevation, vegetation cover, soil hydrology, oceanographic productivity, and wave energy. Global databases allow for the calculation of comparable metrics describing each environmental character across islands. Such metrics can be used today to evaluate relative potential for coupled land-sea conservation efforts and, with sustained investment in monitoring on land and sea, can be used in the future to refine science-based planning tools for integrated land-sea management. As conservation practitioners work to address the effects of climate change, ocean stressors, and biodiversity crises, it is essential that we maximize returns from our management investments. Linking efforts on land, including eradication of island invasive mammals, with marine restoration and protection should offer multiplied benefits to achieve concurrent global conservation goals.

History of Land Cover Change on Santa Cruz Island, Galapagos

Islands are particularly vulnerable to the effects of land cover change due to their limited size and remoteness. This study analyzes vegetation cover change in the agricultural area of Santa Cruz (Galapagos Archipelago) between 1961 and 2018. To reconstruct multitemporal land cover change from existing land cover products, a multisource data integration procedure was followed to reduce imprecision and inconsistencies that may result from the comparison of heterogeneous datasets. The conversion of native forests and grasslands into agricultural land was the principal land cover change in the non-protected area. In 1961, about 94% of the non-protected area was still covered by native vegetation, whereas this had decreased to only 7% in 2018. Most of the agricultural expansion took place in the 1960s and 1970s, and it created an anthropogenic landscape where 67% of the area is covered by agricultural land and 26% by invasive species. Early clearance of native vegetation took place in the more accessible—less rugged—areas with deeper-than-average and well-drained soils. The first wave of settlement consisted of large and isolated farmsteads, with 19% of the farms being larger than 100 ha and specializing in diary and meat production. Over the period of 1961–1987, the number of farms doubled from less than 100 to more than 200, while the average farm size decreased from 90 to 60 ha/farmstead. Due to labor constraints in the agricultural sector, these farms opted for less labor-intensive activities such as livestock farming. New farms (popping up in the 1990s and 2000s) are generally small in size, with <5 ha per farmstead, and settled in areas with less favorable biophysical conditions and lower accessibility to markets. From the 1990s onwards, the surge of alternative income opportunities in the tourism and travel-related sector reduced pressure on the natural resources in the non-protected area.

In Support of Sustainability: The Historical Ecology of Vertebrate Biodiversity and Native American Harvest Practices in the Florida Keys, USA

The Florida Keys are currently experiencing unprecedented loss of lifeways, biodiversity, and cultural heritage due to sea-level rise, catastrophic storm events, unsustainable traditions of resource exploitation, and land development. Yet, these islands have a long history of human occupation and socioecological systems underlying their current sustainability crisis that date back at least 2500 years. Here we report early results of ongoing zooarchaeological research from Upper Matecumbe Key designed to explore anthropogenic engagement with vertebrate fauna between AD 800 and 1250, providing an approximately 500-year window on marine fisheries and terrestrial faunal harvesting for this small island archipelago. Focusing on one of the few remaining, nearly intact Native American archaeological sites in the region, our research contributes to critically needed long-term anthropogenic perspectives on harvest patterns relevant to regional biodiversity conservation and sustainability initiatives.

Dynamic Sustainability, Resource Management, and Collective Action on Two Atolls in the Remote Pacific

Examples of environmental transformation, the creation of sustainable lifeways, and the development of environmentally aware political forms better our understanding of how peoples build on tradition and environmental circumstance to form novel institutions. Using archaeological data, oral histories, genealogies, radiocarbon dating, and Bayesian modeling, we present a timeline of habitation and land-use patterns on Manihiki and Rakahanga, two remote atolls in East Polynesia. We track socioecological change on the atolls from the time of first colonization ca. AD 1200–1400 through to sustained European contact in the mid-1800s. The findings document and temporally anchor collective action-based processes of landscape transformation, the development of a system of cyclical mass migration aimed at sustainable resource use, and the implementation of a novel dual-chiefdom political system. This demonstrates that new levels of political “complexity” manifest as patterns of shifting hierarchy and novel forms of political and ecological management, and can arise in relation to specific social and ecological challenges in systems of any size. The perpetuation and adaptation of aspects of these traditional institutions can help to maintain the sustainability of populations today in the face of climatic and social change.