The Neotoma Paleoecology Database is a community-curated data resource that supports interdisciplinary global change research by enabling broad-scale studies of taxon and community diversity, distributions, and dynamics during the large environmental changes of the past. By consolidating many kinds of data into a common repository, Neotoma lowers costs of paleodata management, makes paleoecological data openly available, and offers a high-quality, curated resource. Neotoma’s distributed scientific governance model is flexible and scalable, with many open pathways for participation by new members, data contributors, stewards, and research communities. The Neotoma data model supports, or can be extended to support, any kind of paleoecological or paleoenvironmental data from sedimentary archives. Data additions to Neotoma are growing and now include >3.8 million observations, >17,000 datasets, and >9200 sites. Dataset types currently include fossil pollen, vertebrates, diatoms, ostracodes, macroinvertebrates, plant macrofossils, insects, testate amoebae, geochronological data, and the recently added organic biomarkers, stable isotopes, and specimen-level data. Multiple avenues exist to obtain Neotoma data, including the Explorer map-based interface, an application programming interface, the neotoma R package, and digital object identifiers. As the volume and variety of scientific data grow, community-curated data resources such as Neotoma have become foundational infrastructure for big data science.

A brief cold–warm–cold climate change during the middle Wisconsinan is described for the first time in North America, based on fossil beetle assemblages at Titusville, Pennsylvania. AMS dating of insect chitin and wood suggests the change occurred between 39,000 and 43,500 yr B.P. Basal peats in river terrace deposits contain arctic–subarctic beetle species representing a climate similar to that found at treeline in Canada, where mean July temperatures range from 10° to 13°C. These cold-adapted beetles were replaced by species representing a climate similar to the mixed coniferous–deciduous forests of southern Canada, where mean July temperatures range from 18° to 20°C. In turn, these warmer-adapted beetles were replaced by arctic–subarctic species in the upper part of the section, representing a climate with mean July temperatures in the range 10°–13°C. The brief warm interval is informally designated the Titusville interstade. The difference in temperature between the colder and warmer intervals is about 5°–7°C. The Titusville interstade is correlated with the Upton Warren Interstade of the British Isles which is of similar age and intensity. It is also correlated with the high sea-surface temperature interval between Heinrich events 4 and 5 represented in North Atlantic sediment cores.

The Norwood site in Sibley Co., Minnesota, contains 1.6 m of silt resting on till and overlain by peat. The base of the peat has been radiocarbon dated at 12,400 ± 60 and the top at 11,200 ± 250 yr B.P. The pollen, plant macrofossils, and insect remains in the basal silt consist of boreal species inhabiting open environments, but not tundra. No modern analogue exists for the insect assemblage, which includes elements of boreal forest, tundra-forest, and western affinities. The transition from an unstable open environment to a stable coniferous forest is reflected by both plant and insect fossils and is interpreted as a successional rather than a climatic event. During this time of significant biologic change, the climate is inferred to have been relatively uniform, with temperatures similar to those presently existing in the boreal forest south of the tundra-forest transition zone. The geologic and ecologic succession at Norwood is generally similar to that presently associated with ice stagnation of the Klutlan Glacier in the Yukon Territory. Localized successional sequences similar to those at Norwood are conceived to have occurred repeatedly during the melting of the Laurentide ice, and thus the proposed model has potentially broad application to the interpretation of late-glacial sequences.

The Gervais Formation of northwestern Minnesota is the oldest known Quaternary stratigraphic unit in the Red River Valley. Wood from the fossiliferous silt and peat member is > 46,900 yr old. The age of the unit is uncertain but may be early Wisconsinan. A well-preserved beetle assemblage consisting of extant species is described from the fossiliferous horizon. Presently, most of the species are widely distributed and occur in Minnesota. The remainder have restricted northern distributions. Included in this group is the weevil Vitavitus thulius, known only from two localities in Northwest Territories. The sedimentary environment indicated by the beetles was a small lake, rich in aquatic and semi-aquatic vegetation. The margins were characterized by open areas and spruce woodland. Species with arctic-alpine distributions indicate a cold environment, but whether it was regional or local in extent could not be determined. If regional, a climate similar to that of the tundra-forest transition zone is postulated with mean July temperatures in the range 11° to 14°C. If the cold environment was restricted, however, the climate may have been similar to that of the Lake Superior region with a mean July temperature of 17°C.

The Mosbeck Site is in the southern part of the Lake Agassiz basin in northwestern Minnesota. The stratigraphic section at the site consists of seven lithologic units, which are from bottom to top (A) unsorted, pebbly, sandy, silty clay, (B) coarse gravel, (C) silty sand, (D) peat, (E) fine sand, (F) interbedded sand and gravel, and (G) unbedded dirty gravel. The lower few centimeters of unit E are unoxidized and contain black spruce and tamarack driftwood, which has been radiocarbon dated at 9940 ± 160 BP (I-3880). Units C-E contain numerous, well-preserved insect and mollusk remains. These fossils have been compared with modern species, and at least 76 insect and 15 mollusk taxa are present. Assuming that their ecological tolerances have changed little in the past 10,000 years, they provide valuable information about the environment of Lake Agassiz. Few of the insects are now found in the region, indicating that the environment has changed. With few exceptions the species present indicate that the climate and vegetation at the time were similar to the present-day climate and vegetation of southeastern Manitoba.

The lithology and faunal contents of the sediment are interpreted as follows. Unit A is Late Wisconsinan glacial sediment. Unit B is a lag concentrate formed by wave action during a regressive phase of Lake Agassiz. Unit C is the sediment of a small body of water that formed when the level of Lake Agassiz had dropped below the site. The banks were covered with a spruce forest. Open water gave way to swampy conditions, and unit D was formed. Both units C and D were deposited during the low-water Moorhead Phase of Lake Agassiz. Units E and F are shoreline sediment deposited as the lake level rose, drowning the vegetation. Unit G is modern ditch spoil.

Cold-adapted beetles colonized the lowlands of the Lake Region of south-central Chile following the retreat of glaciers from their maximum extent at about 19,500 yr B.P. The beetle fauna from 18,000 to 14,000 yr B.P. was characterized by species of moorland habitats. This fauna was species-poor compared to later faunas of the postglacial interval. By 14,000 yr B.P. arboreal species were replacing species of open habitats, reflecting a change toward a warmer climate. By about 12,500 yr B.P. fossil beetle assemblages consisted entirely of rain forest species. The fauna of the postglacial interval was about five times as species-rich as that of the glacial interval. The change in species composition and greater diversity of the beetle fauna was produced by an increase in mean annual temperature estimated to be about 4°–5°C. This was the last major climatic change to affect profoundly the biota of the middle latitudes of South America. The fossil beetle assemblages do not imply a reversal to a colder climate at the time of the European Younger Dryas interval between 11,000 and 10,000 yr B.P.

Fossils from sites of Late Quaternary age in North America provide tangible evidence of temporal changes in the character of the northern beetle fauna. Based on a synthesis of the fossil data with analyses of the present distributions for northern species, a rudimentary model is proposed to explain the recent history of the fauna of the arctic and the boreal forest.An open-ground beetle fauna of arctic–subarctic affinities had become established along the southern margin of the Laurentide ice sheet in the midcontinent by 20 500 years before present (yr B.P.). Climatic warming decimated this fauna throughout lowland areas at some time between 16 700 and 15 300 yr B.P.; small populations of some arctic–subarctic species, however, survived within either alpine habitats of the Cordillera and Appalachians or specialized environments associated with stagnant ice.Populations of the same arctic–subarctic beetle species existed within the ice-free Alaska–Yukon refugium throughout the late Wisconsinan. During the Holocene, this region served as the principal centre-of-origin for the dispersal of the arctic–subarctic beetle fauna.The beetle fauna of the boreal forest was also displaced southward by Late Wisconsinan glaciation. By 15 300 yr B.P., however, this fauna had largely replaced the arctic–subarctic beetle fauna along the ice margin of the midcontinent. Evidence provided by fossils from a series of sites demonstrates that beetle species of the boreal forest dispersed northward into Canada as the ice front receded.