Geology topics

Michael E. Akresh

Publications and source records attributed to Michael E. Akresh.

3 recordsLinked to original sources

USGS2026

Accumulation of per- and polyfluoroalkyl substances (PFAS) and their association with immune parameters in nestling ospreys (Pandion haliaetus) from Chesapeake and Delaware Bays, USA

Per- and polyfluoroalkyl substances (PFAS) are a class of widespread, environmentally persistent compounds that pose a potential threat to wildlife and human health. Despite recent efforts to reduce the use of long-chain PFAS in industrial practices and commercial/consumer products, the persistence and solubility of PFAS have led to their detection in wildlife on a global scale. Osprey ( Pandion haliaetus ) have long been used as a sentinel species with an extensive history of serving as an effective bioindicator of contamination. Here we report on a large-scale evaluation of PFAS and potential health effects in osprey from the Chesapeake and Delaware Bays, USA. In 2011 and 2015, we collected plasma samples from osprey nestlings throughout the Chesapeake and Delaware Bay watersheds. We quantified 40 PFAS congeners in osprey plasma via liquid chromatography-mass spectrometry and analyzed plasma for indicators of immune and thyroid function, and plasma biochemistry. In all birds, perfluorooctanesulfonic acid (PFOS) was the most commonly detected PFAS, followed by perfluoroundecanoic acid, (PFUnA) and perfluorodecanoic acid (PFDA). In nestling plasma from Chesapeake Bay, PFOS tended to be a higher average contributor to PFAS profiles compared to samples from Delaware Bay. In contrast, long-chain perfluoroalkyl carboxylic acids (PFCAs) such as PFUnA and PFDA comprised larger percentages of total PFAS in osprey plasma from Delaware Bay relative to Chesapeake Bay. While some PFAS concentrations were associated with plasma health indicators, the proportion of variation explained was low. Overall, our study provides a more thorough understanding of PFAS presence in the Chesapeake and Delaware Bays and is one of the first to examine whether PFAS exposure is associated with adverse health effects in wildlife.

Chesapeake and Delaware Bays↗

USGS2025

Biodiversity on public lands: How community science can help

Species inventories are crucial for conservation but are difficult to assemble and maintain. Bioblitzes, which encourage the public to document biodiversity in a particular area and timeframe, may offer useful information but their integration with other datasets poses challenges. We investigated the potential contribution of bioblitzes to natural resource management using observations from the United States National Park Service (NPS) 2016 Centennial Bioblitz. Through automated cross-referencing over 19,000 iNaturalist “research-grade” observations from 107 national parks with existing park inventory lists, we matched 86% of species documented in the Bioblitz to NPS species lists, based on current taxonomy, and matched another 6% of species using alternative scientific names using our matching process in R. Of the remaining 13.5% that did not match the NPS species lists, we manually found that 84% of the unmatched species were found within the lists or were outside the boundaries of the park, identifying 141 native species that were unrecorded in NPS species lists. Many introduced species were recorded; they were more likely to be documented in parks closer to cities. Parks near cities also drew more participants. Our study shows how public participation, through iNaturalist and bioblitzes, can facilitate biodiversity monitoring across large spatial scales.

Conservation Science and Practice↗

USGS2024

Long-term monitoring reveals management effects on Prairie Warbler colonization, local extinction, and detection in a Massachusetts pine barren

Habitat management can directly impact Setophaga discolor (Prairie Warbler) abundance and distribution. Despite regional declines, Prairie Warbler populations at Camp Edwards (Bourne, MA) have increased. To investigate habitat-management effects on Prairie Warbler populations at Camp Edwards, we used a dynamic-occupancy model to analyze a long-term monitoring dataset collected across 84 point-count sites from 2013 to 2022. The model results indicated that Prairie Warbler colonization and extinction probabilities were impacted by management (measured in years since disturbance). Colonization probability was highest initially after disturbance, then subsequently decreased for ∼50 years, and extinction probability also decreased for ∼25 years. Both probabilities remained low before increasing at ∼75 years since disturbance. The increase in colonization probability >75 years since disturbance may have been an artifact of our study design and incomplete disturbance records. We also found that latitude and longitude significantly affected colonization probability, likely a result of how habitat types are distributed across the base. These results inform how Prairie Warblers respond to long-term management, suggesting that habitat management could improve colonization rates and sustain Prairie Warbler populations.

Massachusetts↗