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Creators/Authors contains: "Olson, Elizabeth"

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  1. Free, publicly-accessible full text available December 9, 2025
  2. Anthropogenically driven environmental change has imposed substantial threats on biodiversity, including the emergence of infectious diseases that have resulted in declines of wildlife globally. In response to pathogen invasion, maintaining diversity within host populations across heterogenous environments is essential to facilitating species persistence. White-nose syndrome is an emerging fungal pathogen that has caused mass mortalities of hibernating bats across North America. However, in the northeast, peripheral island populations of the endangered northern myotis (Myotis septentrionalis) appear to be persisting despite infection while mainland populations in the core of the species range have experienced sharp declines. Thus, this study investigated host and environmental factors that may contribute to divergent population responses. We compared patterns of pathogen exposure and infection intensity between populations and documented the environmental conditions and host activity patterns that may promote survival despite disease invasion. For island populations, we found lower prevalence and less severe infections, possibly due to a shorter hibernation duration compared to the mainland, which may reduce the time for disease progression. The coastal region of the northern myotis range may serve as habitat refugia that enables this species to persist despite pathogen exposure; however, conservation efforts could be critical to supporting species survival in the long term. 
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    Free, publicly-accessible full text available January 1, 2026
  3. NA (Ed.)
    Speleothem paleoclimate records from the Peruvian Andes have been interpreted to reflect the strength of the South American monsoon. While these interpretations have been verified through comparison with other regional and global climate records, the mechanics of the cave environment that facilitate the preservation of this signal with such consistency remain unstudied. Here, we present four years of environmental data from Huagapo and Pacupahuain cave, and one year from Antipayarguna cave. The data reveal that the cave environment is very stable with little to no change in temperature and 100% relative humidity year-round. This stability in cave air is juxtaposed with the monsoonal drip water pulse that increases drip rates over 40 times on average across all seven monitored drip sites. Compared to the amount-weighted precipitation average δ18Oprecip value, the cave drip water δ18ODW values are evaporatively 18O enriched during infiltration through the soil/epikarst. As the monsoonal precipitation pulse fades and drip rates decrease, changes in the drip water chemistry (trace elements Mg/Ca and Sr/Ca, dissolved inorganic carbon δ13CDW, and δ18ODW values) indicate that prior calcite precipi- tation (PCP) drives the trace element and δ13CDW variability. The δ13Cc and δ18Oc values of farmed slide calcite are highly variable. However, high drip rate and lower cave air pCO2 during the monsoon combine to increase calcite precipitation rates. This causes speleothem records from these caves to be weighted toward annual monsoon conditions. Calcite isotope values from actively growing stalagmite tops support this finding. These results suggest that speleothems from these caves are sensitive to changes in monsoon precipitation amount, because it determines the duration of the monsoon drip water pulse, and therein, the extent of dry season PCP. Further, these data indicate that heterogeneity in the dolomitic limestone massif causes offsets between the carbon isotopes and trace metal concentrations between the caves, highlighting the need to normalize these datasets when chronology-stacking these proxies. 
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    Free, publicly-accessible full text available November 1, 2025
  4. This article examines the U.S. legislative and policy landscape and its historical and contemporary recognition of young people as caregivers and their importance to public health, both as care providers and as a category of special concern for overall wellbeing. Drawing on feminist geographies of health to situate a historical analysis, we aim to answer two key questions: First, what is the history of recognition of caregiving youth in key moments of federal action to address family caregiving needs? Second, how might we use this history to better understand and analyze the patchwork geography of caregiving youth recognition in the U.S. and other countries that similarly lack formal national policy recognition to improve and enhance public health? We use the term patchwork to describe how federal recognition of caregiving youth in broader debates about public health is uneven across both time and space, and contingent upon civil society, non-profit organizations, and researchers working in and with geographically bound communities. Our results illustrate how a focus on the relationships of recognition, both in the past and the present and at local and national scales, reveals a different perspective on caregiving youth in the U.S. with a much more complex history than previously identified. The article describes how relationships established in the absence of federal policy or legislation are sometimes directed towards building more formal recognition, and other times with the goal of changing practices in a specific location. 
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  5. Lake Junín, located in the uppermost Amazon Basin in central Peru, was drilled as part of the International Continental Drilling Program in 2015. A piston core with a composite length of ~95 m provides a continuous archive of upstream glacial activity spanning ~700,000 years. The age-depth model was established with 80 AMS 14C dates, 12 U-Th dated intervals of authigenic calcite, and 17 geomagnetic relative paleointensity tie points, and yields an age of 677±20 ka at 88 m. Four samples from near the base of the core reveal normal polarity paleomagnetic directions, consistent with an age younger than ~773 ka. The composite section comprises intervals of siliciclastic sediment intercalated with intervals dominated by authigenic calcite. The siliciclastic-rich intervals have a consistent signature, with relatively low concentrations of carbonate and organic carbon, and high values of bulk density, magnetic susceptibility and concentrations of elements derived from glacial erosion of the non-carbonate fraction of the regional bedrock. We find that tropical glaciers tracked changes in global ice volume and followed a clear ~100,000-year periodicity. Two caves, Huagapo and Pacupahuain, are located within 25 km of Lake Junín and provide a basis for testing and refining the age model of the Lake Junín drill core based on the high precision and accuracy of Uranium series dates for speleothems from these caves. The assumption here is that significant changes in regional ice volume will also be recorded in the 18O of cave drip water and thus in speleothems. Our initial target interval is the 9-8 marine isotope stage (MIS) boundary (~300 ka), which is recorded in the Junín drill core as an abrupt increase in the influx of glacigenic sediment, and in stalagmite 22-22 from Huagapo Cave as an abrupt 4.5‰ decrease in 18Ocalcite. The age of the onset of this transition in the Junín drill core is about 25 kyr older than that in Stal 22-22, and this difference is within the age model error envelope for the Junín drill core. Similar MIS boundaries provide the basis for adjustments in the Junín age model, which will improve the precision of correlation of this continuous record of tropical glaciation with paleoclimate archives in extra tropical regions. 
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  6. Glacial-interglacial transitions and abrupt millennial-scale events are the most prominent features in many paleoclimate records. Understanding these oscillations requires high-resolution time series from multiple locations to constrain the latitudinal response to forcings. Few high-resolution records exist from the Southern Hemisphere tropics that predate the last two glaciations. We present a high-resolution speleothem oxygen and carbon isotope record from Huagapo Cave in the Central Peruvian Andes covering Marine Isotope Stage (MIS) 8 glacial and MIS 9 interglacial (339 to 249 ka). Uranium-series dates on three stalagmites (n=18) with small age uncertainty ±1% allows us to resolve abrupt climate events similar in structure and duration to Dansgaard-Oescchger and Heinrich events. The South American Summer Monsoon (SASM) controls modern hydroclimate variability in the Andes, and previous records from Huagapo Cave have provided records of past SASM variability. Termination three (T-III) in our record has a steep increase in δ18O values of 5‰, punctuated by two stadial event decreases of ~3‰ (S8.1 and S8.2). This pattern is mirrored in the δ13C record, indicating that these millennial-scale events record hydroclimate and vegetation productivity changes. The same structure as our T-III record is found in other records globally, where they are noted to be Heinrich-like events. Frequency analysis indicates that the occurrence of these abrupt events changes between glacial cycles. Precession is weakly expressed in the δ18O record during MIS 8; similar to speleothem records from the region dating to the Last Glacial Maximum (LGM). Global ice cover and sea levels were similar in the LGM and MIS 8, but the Milankovitch insolation forcing differed. This change in SASM behavior is not observed in the East Asian monsoon, where the precession signal is dominant throughout. Interglacial precessional control is apparent during the latter half of MIS 9 and during Huagapo Cave intervals dating to MIS 6 and 7. These data indicate that the response to high-latitude forcing in the Southern Hemisphere tropics fluctuates through time, and potential explanations for low-latitude sensitivity to forcing factors are further explored. 
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  7. Recent studies have improved our understanding of how karst hydrology impacts variability in modern cave drip water δ18O values and the resultant calcite δ18O values of speleothem paleoclimate records. Monitoring of cave drip water isotope values reveals that flow path controls the differences in drip site values in many caves worldwide. We present a case study of three caves from the central Peruvian Andes where isotopic differences between sites are informed by monitoring data. Relative humidity at Huagapo and Pacupahuain caves is 100% year-round with no fluctuations, so any isotopic fractionation of waters must occur in the vadose zone or epikarst. Precipitation isotope data from the 2022-2023 year show differences with elevation, where annual mean precipitation at 3600 masl (meters above sea level) is, on average, 2‰ greater than precipitation at 4100 masl. Cave drip water was sampled four times (April, June, and November 2022, and June 2023). Average drip water δ18O values were lowest at the high elevation (4004 masl) cave of Antipayargunan -14.7 ± 2.5‰; similar values were found at the lowest elevation (3600 masl) cave of Huagapo -14.5 ± 1.2‰. Pacupahuain cave had the highest values with an average of -13.9 ± 1.7‰. The higher values at Pacupahuain Cave (3800 masl) may be attributed to higher evaporation due to vadose zone residence time, a lower average recharge elevation for this catchment and/or potential contribution from a sinkhole lake (Lago Gallerina) above the cave. Huagapo Cave is large, and sampling sites over 1 km in distance show that the δ18O value of drip water increases by 0.5‰ with increasing distance from the cave entrance. Drip counting sensor data and a continuous SYP autosampler at Pacupahuain Cave provide a time series showing that drip rate peaks during the monsoon season. More specifically, the data show a maximum of 2 ‰ difference in drip water at the autosampler site between the end of the wet season in May and the middle of the dry season in August – at which point drips cease for six months. Seasonal recharge dominates most drip water sites, while drip counters show evidence for fracture and diffuse flow-dominated drip sites. These data suggest that, similar to other cave sites, flow path is important for intra-cave differences in drip water isotope values. However, we find that karst hydrology plays a more dominant role between caves. 
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  8. Abstract SNAPSHOT USA is a multicontributor, long‐term camera trap survey designed to survey mammals across the United States. Participants are recruited through community networks and directly through a website application (https://www.snapshot-usa.org/). The growing Snapshot dataset is useful, for example, for tracking wildlife population responses to land use, land cover, and climate changes across spatial and temporal scales. Here we present the SNAPSHOT USA 2021 dataset, the third national camera trap survey across the US. Data were collected across 109 camera trap arrays and included 1711 camera sites. The total effort equaled 71,519 camera trap nights and resulted in 172,507 sequences of animal observations. Sampling effort varied among camera trap arrays, with a minimum of 126 camera trap nights, a maximum of 3355 nights, a median 546 nights, and a mean 656 ± 431 nights. This third dataset comprises 51 camera trap arrays that were surveyed during 2019, 2020, and 2021, along with 71 camera trap arrays that were surveyed in 2020 and 2021. All raw data and accompanying metadata are stored on Wildlife Insights (https://www.wildlifeinsights.org/), and are publicly available upon acceptance of the data papers. SNAPSHOT USA aims to sample multiple ecoregions in the United States with adequate representation of each ecoregion according to its relative size. Currently, the relative density of camera trap arrays varies by an order of magnitude for the various ecoregions (0.22–5.9 arrays per 100,000 km2), emphasizing the need to increase sampling effort by further recruiting and retaining contributors. There are no copyright restrictions on these data. We request that authors cite this paper when using these data, or a subset of these data, for publication. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the US Government. 
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