Aeroecology, an emerging ecological frontier for addressing modern conservation challenges

Principal Investigator: Kyle Horton, Colorado State University, Fort Collins, CO, USA

NASA New (Early Career) Investigator Program in Earth Science

Project Summary: The lower atmosphere harbors a tremendous amount of biodiversity. Each spring and fall, trillions of migratory organisms of thousands of species traverse this medium — a medium that has long been overlooked as a critical ecological habitat. Migratory organisms connect earth’s hemispheres and serve as bellwethers of ecosystem health and changing environments. Evidence of declines in migratory organisms, particularly birds, is overwhelming, highlighting an important need for research and tools that can direct conservation action to mitigate threats to these organisms. Yet most studies of associated threats for migratory species have focused on terrestrial habitats, underscoring a fundamental knowledge gap. Airspaces are increasingly becoming crowded, with more anthropogenic structures (e.g., wind turbines, high-rise building, communication towers) populating the lowest reaches of the troposphere than ever before — posing an ever-increasing threat to wildlife. In the contiguous U.S., annual fatal bird collisions with these structures cumulatively number in the hundreds of millions. Furthermore, artificial light pollution from these structures can greatly magnify this threat. The scope and scale of this concern requires a revision of our understanding of the ecology of airspace, a new frontier known as aeroecology. Yet as our recognition of airspace as a habitat grows, so must the tools to quantify, characterize, and predict the movement of organisms through these spaces. Ecological forecasting of bird movements at relevant spatial and temporal scales provides a novel, data-intensive pathway toward real-time ecological monitoring and dynamic conservation actions. Short-term conservation actions may include the temporary removal of aerial obstacles (e.g., wind turbines, aircraft) or point-source pollutants (e.g., light pollution). However, days, hours, or even minutes can make the difference between successful conservation intervention and missed opportunity. The detection of in-flight migratory birds poses a unique set of challenges, particularly because the majority of North American species migrate at night (∼80%). NEXRAD weather radar is one of the only sensors that can monitor these nocturnal movements. Moreover, it is the only sensor platform with the ability to quantify these massive movements across continental scales. However, radar alone cannot provide a predictive framework to solve the aforementioned challenges. It is through the integration with annual geospatial products that radar data can be fully realized — NASA remote sensing products fill this need.

Understanding Urban Centers as Ecological Traps for Avian Migrants

Principal Investigator: Kyle G. Horton, Colorado State University, Fort Collins, CO, USA

Co-Investigator: Geoffrey M. Henebry, PhD, Michigan State University, East Lansing, MI, USA

NASA Biodiversity

Project Summary: Human populations are shifting toward urban centers. Currently, more than 80% of the United States population resides in cities — up 64% since 1950, with projections reaching 89% by 2050. Urban land area belies the outsized environmental, socioeconomic, and cultural footprints associated with city living. Cities are hotspots: of wealth creation and waste generation; of technical and cultural innovations; of greenhouse gases and toxic emissions; of impervious islands emitting heat and light; of denser human populations coupled with lower biotic diversity. Understanding the scope and impact of urban development on natural communities, both within urban areas, but also across these areas at continental scales, is pivotal for sustainable development, urban planning, and the intentional conservation of biodiversity. Remote sensing of biotic diversity has advanced considerably in the past few decades, ushering in a new era of multi-sensor synthesis, bringing together various and diverse observational datastreams to characterize, map, monitor, and model the location — and even the movement — of species and populations. We propose a novel approach to understand the influence of urban areas on bird migration by bringing multiple NASA products together with analysis of in-situ weather radar data and citizen science observations. We focus on the Central Flyway and the urban archipelago across the U.S. Great Plains. We will build our analytical dataset along a north-south transect by articulating observations from ECOSTRESS (land surface temperature and emissivity,  evapotranspiration, and evaporative stress index), DESIS (a suite of complementary advanced spectral indices), and GEDI (geolocated waveforms, canopy cover fraction and leaf area index profiles) upon a backbone of time series from NLCD, MODIS, VIIRS, and Landsat. Our specialized reanalysis of NEXRAD weather radar data (>25 years) will allow us to derive system-wide measures related to nocturnal bird migration, including measures of the number of airborne migrants, phenophases of migrant passage, speed and direction of nightly movements, and migrant land use during stopover. Our inclusion of eBird citizen science measures will provide detailed daytime measures of species richness, relative occurrence, and phenology.