More Like this

1. Detecting Classic Maya Settlements with Lidar-Derived Relief Visualizations

   https://doi.org/10.3390/rs12172838  

   Thompson, Amy E. ( September 2020 , Remote Sensing)

   null (Ed.)

   In the past decade, Light Detection and Ranging (lidar) has fundamentally changed our ability to remotely detect archaeological features and deepen our understanding of past human-environment interactions, settlement systems, agricultural practices, and monumental constructions. Across archaeological contexts, lidar relief visualization techniques test how local environments impact archaeological prospection. This study used a 132 km2 lidar dataset to assess three relief visualization techniques—sky-view factor (SVF), topographic position index (TPI), and simple local relief model (SLRM)—and object-based image analysis (OBIA) on a slope model for the non-automated visual detection of small hinterland Classic (250–800 CE) Maya settlements near the polities of Uxbenká and Ix Kuku’il in Southern Belize. Pedestrian survey in the study area identified 315 plazuelas across a 35 km2 area; the remaining 90 km2 in the lidar dataset is yet to be surveyed. The previously surveyed plazuelas were compared to the plazuelas visually identified on the TPI and SLRM. In total, an additional 563 new possible plazuelas were visually identified across the lidar dataset, using TPI and SLRM. Larger plazuelas, and especially plazuelas located in disturbed environments, are often more likely to be detected in a visual assessment of the TPI and SLRM. These findings emphasize the extent and density of Classic Maya settlements and highlight the continued need for pedestrian survey to ground-truth remotely identified archaeological features and the impact of modern anthropogenic behaviors for archaeological prospection. Remote sensing and lidar have deepened our understanding of past human settlement systems and low-density urbanism, processes that we experience today as humans residing in modern cities. 

   more » « less
2. Structural and compositional dimensions of phytochemical diversity in the genus Piper reflect distinct ecological modes of action

   https://doi.org/10.1111/1365-2745.13691  

   Philbin, Casey S. ; Dyer, Lee A. ; Jeffrey, Christopher S. ; Glassmire, Andrea E. ; Richards, Lora A. ( June 2021 , Journal of Ecology)

   An increasing number of ecological studies have used chemical diversity as a functionally relevant, scalable measure of phytochemical mixtures, demanding more rigorous attention to how chemical diversity is estimated. Most studies have focused on the composition of phytochemical mixtures and have largely ignored structural concerns, which may have greater importance for ecological function. Here, we explore the development of structural complexity and compositional diversity resulting from different biotic and abiotic interactions inPiper kelleyiTepe (Piperaceae). We also describe how variation in structural complexity and compositional diversity differs between two congeners,P. kelleyiandP.reticulatum. To better interpret these results, we have developed a framework for interpreting these dimensions of chemical diversity in phytochemical mixtures.

   We used the tropical shrub,P.kelleyi, as a model system to examine interactions between ecological factors and dimensions of phytochemical diversity. We also compared compositional diversity and metabolic complexity inP. kelleyiandP. reticulatumusing liquid chromatography and¹H NMR, respectively, to examine trade‐offs between compositional diversity and structural complexity. A framework is provided to generate meaningful estimates of the structural complexity of phytochemical mixtures as measured by¹H NMR.

   Piperis an abundant plant genus that supports diverse insect communities throughout the tropics. Subtle changes in understorey forest light were associated with increases in herbivory that directly increased compositional diversity and indirectly decreased structural complexity inP. kelleyi. This was attributed to the production of oxidation products resulting from herbivory‐driven decomposition of structurally complex defence compounds. This type of complex result would remain undetected using standard chemical ecology approaches and accounts for the detailed molecular changes that are likely to affect species interactions.

   Synthesis. Our quantitative framework provides a method for considering trade‐offs between structural complexity and compositional diversity and the interpretation of analytical approaches for each. This methodology will provide new theoretical insights and a more sophisticated model for examining the ecology and evolution of chemically mediated interactions.

    

   more » « less
3. Planning abilities of wild chimpanzees (Pan troglodytes troglodytes) in tool-using contexts

   https://doi.org/10.1007/s10329-023-01106-4  

   Musgrave, Stephanie ; Koni, David ; Morgan, David ; Sanz, Crickette ( December 2023 , Primates)

   Planning is a type of problem solving in which a course of future action is devised via mental computation. Potential advantages of planning for tool use include reduced effort to gather tools, closer alignment to an efficient tool design, and increased foraging efficiency. Chimpanzees (Pan troglodytes troglodytes) in the Goualougo Triangle use a variety of different types of tools. We hypothesized that procurement strategy (brought to the termite nest, manufactured or acquired at the termite nest, or borrowed from others) reflects planning for current needs, with tool transport behavior varying by tool type and by age and sex class. It is also possible that chimpanzees anticipate the need for tools at future times, which would be evidenced by transporting multiple tool types for a sequential task. One year of video recordings at termite nests were systematically screened for tool procurement; data comprised 299 tool procurement events across 66 chimpanzees. In addition, we screened video recordings of leaf sponging and honey gathering, which resulted in another 38 procurement events. Fishing probes, which are typically used during a single visit, were typically transported to termite nests, while puncturing tools, which are durable and remain on site, were more often acquired at termite nests. Most tools transported in multiples were fishing probes, perhaps in anticipation that a single probe might not last through an entire foraging bout or might be transferred to another chimpanzee. We further documented that chimpanzees transported tool sets, comprising multiple different tool types used in sequence. Mature chimpanzees transported tools more often than did immatures. These observations suggest that chimpanzees plan tool use flexibly, reflecting the availability of raw materials and the likelihood that specific tool types will be needed for particular tasks. Developmental studies and further integration of behavioral, spatial, and archaeological data will help to illuminate the decision making and time depth of planning associated with tool technologies in living primates and hominin ancestors.

    

   more » « less
4. A New Instrument for Determining the Coarse-Mode Sea Salt Aerosol Size Distribution

   https://doi.org/10.1175/JTECH-D-20-0197.1  

   ( November 2021 , Journal of Atmospheric and Oceanic Technology)

   Sea salt aerosol (SSA) plays a significant role in the atmosphere through aerosol direct and indirect effects, and in atmospheric chemistry as a source of tropospheric bromine. In situ measurements of coarse-mode SSA particles are limited because of their low concentration and relatively large sizes (dry radiusr_d> 0.5μm). With this in mind, a new, low-cost, easily usable method for sampling coarse-mode SSA particles in the marine boundary layer was developed. An SSA particle sampler that uses an impaction method was designed and built using 3D printing and Arduino microcontrollers and sensors. It exposes polycarbonate slides to ambient airflow remotely on a kite-based platform to capture coarse-mode SSA particles. Because it is a smaller version of the Giant Nucleus Impactor (GNI), designed for use on aircraft, it is named the miniature Giant Nucleus Impactor (miniGNI). After sample collection, the same optical microscope methodology utilized by the GNI was used to analyze the wetted salt particles that impacted onto the slides. In this proof-of-concept study, multiple miniGNIs were attached serially to a kite string, allowing for sampling at multiple altitudes simultaneously. The robustness of the results from this new instrument and methodology for sampling at ambient RH (~75%) the SSA particle size distribution withr_d> 3.3μm are compared with a similar study. We find that the SSA particle number concentration decreases weakly with altitude and shows no correlation to instantaneousU₁₀wind speed along the windward coastline of Oʻahu in the Hawaiian Islands.

    

   more » « less
5. Molecular analysis of an ancient Thule population at Nuvuk, Point Barrow, Alaska

   https://doi.org/10.1002/ajpa.23746  

   Tackney, Justin ; Jensen, Anne M. ; Kisielinski, Caroline ; O'Rourke, Dennis H. ( January 2019 , American Journal of Physical Anthropology)

   The North American archaeological record supports a Holocene origin of Arctic Indigenous peoples. Although the Paleo‐Inuit were present for millennia, archaeological and genetic studies suggest that modern peoples descend from a second, more recent tradition known as the Neo‐Inuit. Origins of the Neo‐Inuit and their relations to the earlier and later Indigenous peoples are an area of active study. Here, we genetically analyze the maternal lineages present at Nuvuk, once the northernmost community in Alaska and located in a region identified as a possible origin point of the Neo‐Inuit Thule. The cemetery at Nuvuk contains human remains representing a nearly one thousand year uninterrupted occupation from early Thule to post‐contact Iñupiat.

   We selected 44 individuals from Nuvuk with calibrated dates between 981 AD and 1885 AD for molecular analysis. We amplified and sequenced the hypervariable segment I of the mitogenome. We compared the Nuvuk data with previously published sequences from 68 modern and ancient communities from across Asia and North America. Phylogeographic analyses suggest possible scenarios of Holocene Arctic and sub‐Arctic population movements.

   We successfully retrieved sequence data from 39 individuals. Haplogroup frequencies in Nuvuk were typed as 66.7% A2b1, 25.6% A2a, and 7.7% D4b1a2a1a. These results suggest that the population at Nuvuk was closest to the ancient Thule and modern Inuit of Canada, and to the Siberian Naukan people. We confirm that haplogroups A2a, A2b1, D2a, and D4b1a2a1a appear at high frequency in Arctic and sub‐Arctic populations of North America and Chukotka. Sister clades D2b and D4b1a2a1b are present in Asian and Eastern European populations.

   The ancient mitochondrial sequences from Nuvuk confirm the link between the North Slope and the Thule who later spread east, and the maternal discontinuity between the Neo‐Inuit and Paleo‐Inuit. We suggest haplogroups A2a, A2b, and D4b1a2a1a are linked to the ancestors of the Thule in eastern Beringia, whereas the D2 and D4b1a2a1 clades appear to have Asian Holocene origins. Further Siberian and Alaskan genomes are necessary to clarify these population migrations beyond a simple two‐wave scenario of Neo‐Inuit and Paleo‐Inuit.

    

   more » « less