Mon, Aug 02, 2021:On Demand
Background/Question/Methods
One of the major consequences of global climate change has been changes in plant phenology that occur with shifting growing seasons. As shifts in plant phenology will likely have a variety of effects on ecosystem structure and function, the need to accurately track plant phenophases has become increasingly important. We asked what plant species are consistently visible and how does their phenology change over time in images captured through fixed, ground level time-lapse photography at a saline tallgrass prairie site in northeast North Dakota, USA. Images were part of the national PhenoCam project and were collected from 2015 to 2020. For each growing season, we used daily PhenoCam images to identify plants and document changes in plant phenophases. We recorded five main phenophases for each species: visible growth, first flower, peak flowering, last flowering, and end of season senescence.
Results/Conclusions We clearly identified nine plant species, including two cool-season grasses and four Asteraceae species. The grasses, Bromus inermis and Poa pratensis, a monocot, Asparagus officinalis, and the Asteraceae species Helianthus maximiliani and Symphyotrichum ericoides were present all six years. Melilotus officinalis, Anenome canadensis, Solidago canadensis, and Cirsium arvense were present, but without the same yearly consistency. P. pratensis growth marked the beginning and end of each growing season, with an average start date of April 26 and an average end date of October 19. A prescribed burn in fall 2017 altered the plant species composition and phenology during the 2018 growing season, with plant phenophases occurring approximately five to ten days earlier than previously observed. In this case, H. maximiliani flowering days decreased and S. ericoides flowering days increased. Additionally, M. officinalis reappeared after a two-year absence. Not all the phenophases of each identified species could be consistently detected. For example, Anenome canadensis could be identified in the images, but this species’ size and position in the view made phenophase identification difficult. Results from this study will be used to inform longer time-scale satellite image based assessments of climate change effects on plant phenophases in this region.
Results/Conclusions We clearly identified nine plant species, including two cool-season grasses and four Asteraceae species. The grasses, Bromus inermis and Poa pratensis, a monocot, Asparagus officinalis, and the Asteraceae species Helianthus maximiliani and Symphyotrichum ericoides were present all six years. Melilotus officinalis, Anenome canadensis, Solidago canadensis, and Cirsium arvense were present, but without the same yearly consistency. P. pratensis growth marked the beginning and end of each growing season, with an average start date of April 26 and an average end date of October 19. A prescribed burn in fall 2017 altered the plant species composition and phenology during the 2018 growing season, with plant phenophases occurring approximately five to ten days earlier than previously observed. In this case, H. maximiliani flowering days decreased and S. ericoides flowering days increased. Additionally, M. officinalis reappeared after a two-year absence. Not all the phenophases of each identified species could be consistently detected. For example, Anenome canadensis could be identified in the images, but this species’ size and position in the view made phenophase identification difficult. Results from this study will be used to inform longer time-scale satellite image based assessments of climate change effects on plant phenophases in this region.