Forest ecosystems play a major role in sequestering atmospheric carbon dioxide, which can help offset the detrimental effects of anthropogenic carbon emissions. However, climate change has and will continue to affect the phenology of forest ecosystems’ carbon uptake, changing both the “carbon uptake transition date” - when forests shift from being a net carbon source to sink - and the “green-up date” reflecting the onset of bud burst. Previous studies have shown that a forest's carbon uptake transition date correlates to the date when soil temperature warms enough to surpass mean annual air temperature (soil-air temperature model). However, we still don't know if this simple relationship holds across different sites or over longer time periods. In this study, we explore the relationship between climate and both types of phenological transition dates using over 200 site years of data between 1997 and 2022. Using flux tower data from 18 sites across North America and Europe, we derive three potential carbon uptake transition dates corresponding to the dates when 10%, 25%, and 50% of seasonal net ecosystem exchange (NEE) amplitude is reached. Using PhenoCam data, we then derive three potential green-up dates corresponding to when 10%, 25%, and 50% of total seasonal green chromatic coordinate (GCC) is reached (the greenness model). We evaluate our model estimates using concordance coefficients, a metric of agreement between two measures, to determine which process, carbon uptake or budburst, is best predicted by the soil-air temperature model and to what extent. We find that variation in phenological relationships can be attributed to different regional and bioclimatic groups, highlighting potential biome-specific strengths and limitations of the soil-air temperature model. This model offers a simple approach to better understand phenological transitions and identify potential and limitations for a simple universal SOS prediction approach in deciduous forests.

Invasion Potential: The unrealized distribution of invasive species that may occur with future climate conditions. Here the term is used to describe both 1) the potential for an invasive species to invade and 2) the potential for an environment to be invaded. Summary: As Earth’s climate changes, it alters the characteristics of ecosystems which can stress native species, increasing a community’s susceptibility to novel invasions. This can increase the invasion potential of an invasive plant species or region. Whether or not the invasion potential is realized depends on several factors including species interactions (which are difficult to quantify) and the traits of the invasive and native species in the community. Climate and species distribution models can be used to predict invasion potential, and these predictions can inform management decisions to help protect ecosystems from invasive plant species. This management challenge will overview two species specific examples of invasion potential, then outline some general strategies for better management.

Tongue River 2100: Future Tongue River Streamflow Estimates to Enable Northern Cheyenne Data-Driven Water Management and Planningn presentation given during the 2023 outreach trips to the following: Wyoming State Engineer’s Office, Sheridan, WY Tongue River Water Users Association, Tongue River Dam, MT Northern Cheyenne Tribe Citizens, Birney, MT & Ashland, MT Northern Cheyenne Tribal Historical Preservation Office, Lame Deer, MT Chief Dull Knife College, Lame Deer, MT Northern Cheyenne Tribe, Lame Deer, MT

Mountain ecosystems are prioritized by the North Central CASC due to the provided water resources, recreation opportunities, and endemic biodiversity. Mountain ecosystems are vulnerable to climate change due to elevation-dependent warming, loss of snowpack, reduction in physical area at higher elevations, and general sensitivity of alpine species to climate. Current climate adaptation strategies for this ecosystem include preservation of potential species refugia, connection of migratory pathways between habitat, management of recreation impacts, and modification of snow inputs. Many of these landscapes also fall within wilderness designation, constraining the range of options available for climate adaptation strategies. Further, at fine spatial and temporal scales applicable to management the patterns of climate change, subsequent biological responses, and success of climate adaptation strategies will likely be difficult to generalize across sites due to the idiosyncrasies of local geography (e.g., topography, soils).  This project’s overall objective is to produce a robust initiative for climate adaptation research in mountain ecosystems for the North Central CASC. This synthesis work aims to increase knowledge production and co-production of climate adaptation strategies for mountain ecosystems with federal, tribal, and academic partners in the North Central region. The research team investigate what are our knowledge gaps of mountain ecosystem responses to climate change that limit our ability to perform successful climate adaptation by: 1. Synthesizing literature on climate and biological trends in mountains across the study region; 2. Synthesizing literature on societal interests (e.g., water resources) and management actions (e.g., preservation) for this ecosystem in the context of changing climate; 3. Summarizing a prospective regional research agenda for climate adaptation in the mountain ecosystem for presentation to stake- and rights-holders; 4. Analyzing of publicly available biological datasets in mountains for temporal trends, regional patterns; 5. Documenting of climate adaptation case studies to address regional mountain management priorities, challenges, and opportunities; and 6. Creating a research and management initiative for climate adaptation in mountain ecosystems in the North Central region.

In this work we find that the future of fire in the U.S. will likely be characterized by more frequent and larger fires in most regions due to the changing climate and more people starting fires in new places. For the period 2020-2060, we project an average increase in the number of fires (+56%) and burned area (+59%) across the U.S. compared to the historical period (1984-2019). Our models indicate that there will be more fires in the Eastern U.S., which historically has had low fire activity, while the Western U.S. will see more fires that are larger than the largest fires on record. These changes have substantial implications for ecosystem and fire management, disaster response and mitigation, and wildland fire public policy. The work supported an early-career postdoc, provided mentoring and training opportunities, and helped to build a community of postdocs through the NCASC Climate Adaptation Postdoctoral (CAP) Fellows Program of Future of Fire.

Land surface phenology (LSP) products are currently of large uncertainties due to cloud contaminations and other impacts in temporal satellite observations and they have been poorly validated because of the lack of spatially comparable ground measurements. This study provided a reference dataset of gap-free time series and phenological dates by fusing the Harmonized Landsat 8 and Sentinel-2 (HLS) observations with near-surface PhenoCam time series for 78 regions of 10 × 10 km2 across ecosystems in North America during 2019 and 2020. The HLS-PhenoCam LSP (HP-LSP) reference dataset at 30 m pixels is composed of: (1) 3-day synthetic gap-free EVI2 (two-band Enhanced Vegetation Index) time series that are physically meaningful to monitor the vegetation development across heterogeneous levels, train models (e.g., machine learning) for land surface mapping, and extract phenometrics from various methods; and (2) four key phenological dates (accuracy ≤5 days) that are spatially continuous and scalable, which are applicable to validate various satellite-based phenology products (e.g., global MODIS/VIIRS LSP), develop phenological models, and analyze climate impacts on terrestrial ecosystems.

Over the last twenty years, phenology—the study of seasonal life cycle events—has emerged as a key subfield of global change biology. Phenology provides an integrated measure of the organismal response to climate change and is a key driver of the functional responses of ecosystems to climate change. Since I established the PhenoCam Network in 2008, over 200 papers have been published using Phenocam technology, and these papers have added to our understanding of phenology as both an indicator of climate variability and change and a key aspect of ecosystem function. This review examines: (1) the changing phenological research landscape, as represented by phenology-themed papers in Agricultural and Forest Meteorology (AFM), over the last 60 y; (2) the contributions of phenocams and the PhenoCam Network, as reported in the pages of AFM, to the study of phenology; and (3) the lessons I have learned from developing this grassroots effort, and how other researchers might benefit from the PhenoCam Network's successes and failures. Key conclusions to emerge from this review include: (1) the enormous, value-added power of research networks; (2) the importance of both interpersonal relationships and serendipity, in the metamorphosis of ideas into results; and (3) the potential for open, freely-available data to be transformative, in ways that cut across disciplinary, socioeconomic, and demographic barriers. Finally, the development of the PhenoCam Network has been a collaborative, multidisciplinary experiment in team science, and the commitment of my team members and the enthusiasm of my collaborators have been critical to the success of these efforts.