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1. Biomass burning in the Neotropics is exposing migrating birds to elevated fine particulate matter concentrations

   https://doi.org/10.1111/geb.13767  

   La Sorte, Frank A. ; Zuckerberg, Benjamin ; Lepczyk, Christopher A. ; Aronson, Myla F. J. ; Horton, Kyle G. ( October 2023 , Global Ecology and Biogeography)

   A unique risk faced by nocturnally migrating birds is the disorienting influence of artificial light at night (ALAN). ALAN originates from anthropogenic activities that can generate other forms of environmental pollution, including the emission of fine particulate matter (PM_2.5). PM_2.5concentrations can display strong seasonal variation whose origin can be natural or anthropogenic. How this variation affects seasonal associations with ALAN and PM_2.5for nocturnally migrating bird populations has not been explored.

   Western Hemisphere.

   2021

   Nocturnally migrating passerine (NMP) bird species.

   We combined monthly estimates of PM_2.5and ALAN with weekly estimates of relative abundance for 164 NMP species derived using observations from eBird. We identified groups of species with similar associations with monthly PM_2.5. We summarized their shared environmental, geographical, and ecological attributes.

   PM_2.5was lowest in North America, especially at higher latitudes during the boreal winter. PM_2.5was highest in the Amazon Basin, especially during the dry season (August–October). ALAN was highest within eastern North America, especially during the boreal winter. For NMP species, PM_2.5associations reached their lowest levels during the breeding season (<10 μg/m³) and highest levels during the nonbreeding season, especially for long‐distance migrants that winter in Central and South America (~20 μg/m³). Species that migrate through Central America in the spring encountered similarly high PM_2.5concentrations. ALAN associations reached their highest levels for species that migrate (~12 nW/cm²/sr) or spend the nonbreeding season (~15 nW/cm²/sr) in eastern North America.

   We did not find evidence that the disorienting influence of ALAN enhances PM_2.5exposure during stopover in the spring and autumn for NMP species. Rather, our findings suggest biomass burning in the Neotropics is exposing NMP species to consistently elevated PM_2.5concentrations for an extended period of their annual life cycles.

    

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2. The role of artificial light at night and road density in predicting the seasonal occurrence of nocturnally migrating birds

   https://doi.org/10.1111/ddi.13499  

   La Sorte, Frank A. ; Johnston, Alison ; Rodewald, Amanda D. ; Fink, Daniel ; Farnsworth, Andrew ; Van Doren, Benjamin M. ; Auer, Tom ; Strimas‐Mackey, Matthew ; López, ed., Ana Benítez ( March 2022 , Diversity and Distributions)

   Artificial light at night (ALAN) and roads are known threats to nocturnally migrating birds. How associations with ALAN and roads are defined in combination for these species at the population level across the full annual cycle has not been explored.

   Western Hemisphere.

   We estimated range‐wide exposure, predictor importance and the prevalence of positive associations with ALAN and roads at a weekly temporal resolution for 166 nocturnally migrating bird species in three orders: Passeriformes (n = 104), Anseriformes (n = 27) and Charadriiformes (n = 35). We clustered Passeriformes based on the prevalence of positive associations.

   Positive associations with ALAN and roads were more prevalent for Passeriformes during migration when exposure and importance were highest. Positive associations with ALAN and roads were more prevalent for Anseriformes and Charadriiformes during the breeding season when exposure was lowest. Importance was uniform for Anseriformes and highest during migration for Charadriiformes. Our cluster analysis identified three groups of Passeriformes, each having similar associations with ALAN and roads. The first occurred in eastern North America during migration where exposure, prevalence, and importance were highest. The second wintered in Mexico and Central America where exposure, prevalence and importance were highest. The third occurred throughout North America where prevalence was low, and exposure and importance were uniform. The first and second were comprised of dense habitat specialists and long‐distance migrants. The third was comprised of open habitat specialists and short distance migrants.

   Our findings suggest ALAN and roads pose the greatest risk during migration for Passeriformes and during the breeding season for Anseriformes and Charadriiformes. Our results emphasise the close relationship between ALAN and roads, the diversity of associations dictated by taxonomy, exposure, migration strategy and habitat and the need for more informed and comprehensive mitigation strategies where ALAN and roads are treated as interconnected threats.

    

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3. Transfer of nitrogen by migratory birds in the African-Western Eurasian Flyways

   https://doi.org/10.1515/ami-2020-0101  

   Varriano, Sofia ; Mallon, Julie M. ; Folta, Cody ; Coulibaly, Hawa ; Krajcir, Kevin J. ; McClung, Maureen R. ; Fagan, William F. ; Moran, Matthew D. ( October 2020 , Animal Migration)

   null (Ed.)

   Abstract Migrating animals are known to play an important role in nutrient transfer over short distances; however, this phenomenon has not been well studied for long-distance migrants. In this preliminary study, we focused on nitrogen (N) transfer by 44 bird species that migrate from Eurasia to two regions in sub-Saharan Africa that fall into the lowest 10% quantile of global N-deposition (mean annual deposition ≤ 10.44 mg/m 2 /year). We estimated the number of birds that die during the non-breeding season in these areas and then used N content and species-specific mass values to calculate annual N-deposition rates. For these two areas of low N-deposition, we found that bird mortality contributed 0.2 – 1.1% of total nitrogen deposition, which is a relatively small proportion. Therefore, we conclude that nitrogen transfer by long-distance bird migrants using the East Atlantic Flyway and the West Asian-East African Flyway currently has limited impact on the sub-Saharan nitrogen cycle. However, it is worth noting that this impact may have been more important in the past due to larger bird populations and lower background N-deposition (i.e., less anthropogenic impact). 

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4. Chemical Data Assimilation With Aqueous Chemistry in WRF‐Chem Coupled With WRFDA (V4.4.1)

   https://doi.org/10.1029/2023MS003928  

   Ha, Soyoung ; Kumar, Rajesh ; Pfister, Gabriele ; Lee, Yonghee ; Lee, Daegyun ; Kim, Hyun Mee ; Ryu, Young‐Hee ( February 2024 , Journal of Advances in Modeling Earth Systems)

   This study introduces a new chemistry option in the Weather Research and Forecasting model data assimilation (WRFDA) system, coupled with the WRF‐Chem model (Version 4.4.1), to incorporate aqueous chemistry (AQCHEM) in the assimilation of ground‐level chemical measurements. The new DA capability includes the integration of aqueous‐phase aerosols from the Regional Atmospheric Chemistry Mechanism (RACM) gas chemistry, the Modal Aerosol Dynamics Model for Europe (MADE) aerosol chemistry, and the Volatility Basis Set (VBS) for secondary organic aerosol production. The RACM‐MADE‐VBS‐AQCHEM scheme facilitates aerosol‐cloud‐precipitation interactions by activating aerosol particles in cloud water during the model simulation. With the goal of enhancing air quality forecasting in cloudy conditions, this new implementation is demonstrated in the weakly coupled three‐dimensional variational data assimilation (3D‐Var) system through regional air quality cycling over East Asia. Surface particulate matter (PM) concentrations and four gas species (SO₂, NO₂, O₃, and CO) are assimilated every 6 hr for the month of March 2019. The results show that including aqueous‐phase aerosols in both the analysis and forecast can represent aerosol wet removal processes associated with cloud development and rainfall production. During a pollution event with high cloud cover, simulations without aerosols defined in cloud water exhibit significantly higher values for liquid water path, and surface PM₁₀(PM_2.5) concentrations are overestimated by a factor of 10 (3) when wet scavenging processes dominate. On the contrary, AQCHEM proves to be helpful in simulating the wet deposition of aerosols, accurately predicting the evolution of surface PM concentrations without such overestimation.

    

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5. Seasonal associations with urban light pollution for nocturnally migrating bird populations

   https://doi.org/10.1111/gcb.13792  

   La Sorte, Frank A. ; Fink, Daniel ; Buler, Jeffrey J. ; Farnsworth, Andrew ; Cabrera‐Cruz, Sergio A. ( July 2017 , Global Change Biology)

   The spatial extent and intensity of artificial light at night (ALAN) has increased worldwide through the growth of urban environments. There is evidence that nocturnally migrating birds are attracted toALAN, and there is evidence that nocturnally migrating bird populations are more likely to occur in urban areas during migration, especially in the autumn. Here, we test if urban sources ofALANare responsible, at least in part, for these observed urban associations. We use weekly estimates of diurnal occurrence and relative abundance for 40 nocturnally migrating bird species that breed in forested environments in North America to assess how associations with distance to urban areas andALANare defined across the annual cycle. Migratory bird populations presented stronger than expected associations with shorter distances to urban areas during migration, and stronger than expected association with higher levels ofALANoutside and especially within urban areas during migration. These patterns were more pronounced during autumn migration, especially within urban areas. Outside of the two migration periods, migratory bird populations presented stronger than expected associations with longer distances to urban areas, especially during the nonbreeding season, and weaker than expected associations with the highest levels ofALANoutside and especially within urban areas. These findings suggest thatALANis associated with higher levels of diurnal abundance along the boundaries and within the interior of urban areas during migration, especially in the autumn when juveniles are undertaking their first migration journey. These findings support the conclusion that urban sources ofALANcan broadly effect migratory behavior, emphasizing the need to better understand the implications ofALANfor migratory bird populations.

    

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