BRC-BIO: Investigating ecophysiological strategies and drought tolerance of temperate lianas

Vassar College, Poughkeepsie NY

Investigators

Abstract

The concept of global change encompasses not only the direct alteration of the Earth’s climate and atmosphere, but also other human-driven mechanisms which alter the biosphere. Land transformation, overexploitation of natural populations, and exotic species invasions are driving global changes that impact biodiversity and quality of life. Woody vines, known as lianas, are structural parasites that use the structure of nearby trees to gain access to the sunlit canopy and can cause damage or death to the underlying trees. Understanding how these plants access resources such as light and water can inform strategies to control their spread. This project will compare physiological processes, such as photosynthesis and hydraulics, of invasive and native woody vines to characterize traits that contribute to their successful establishment in forested areas. This research will enhance the research skills of undergraduate students via its integration into a plant physiology class and independent research projects at Vassar College, a primarily undergraduate institution. Students involved in the project will do scientific communication outreach to local schools, allowing the students to improve communication skills and improving access to science and its applications at the K-12 level. Research sites will include identified urban forests of Poughkeepsie, NY to inform restoration and conservation plans in large city and town parks. This project will include presentations to local community groups, as well as city parks and planning departments, to encourage community involvement with invasive species control. Global ecosystems are under pressure from many factors including climate change, habitat loss and fragmentation, and biological invasion. As non-native plant species compete with native species for resources, understanding their physiology can improve predictions of competition and environmental responses to inform conservation decisions. Introduced temperate lianas, such as Ampelopsis brevipedunculata (porcelain berry) and Celastrus orbiculatus (Asiatic bittersweet), have been identified as invasive species of concern in the eastern United States. Since they require proximity to trees in order to access the canopy, lianas often germinate in the lower light intensities of the forest understory and must respond quickly to available light to maximize growth. Understory light occurs in patches of intermittent duration and varied size, so maintaining photosynthetic assimilation rates and water use efficiency during these sunflecks is essential for success. The objectives of this proposal are three-fold: 1) to compare photosynthetic and morphological characteristics of competing native and non-native lianas under varied light conditions, 2) quantify the growth traits, biomass allocation, anatomy, and hydraulics of the study species, and 3) investigate light acquisition and hydraulic strategies of these plants under water deficit to simulate climate change scenarios. Complementary measurements of photosynthetic assimilation, alongside rapid chlorophyll fluorescence and stomatal conductance measurements, will allow the researchers to characterize several traits, including maximum rates of electron transport and carbon assimilation, conductance of CO2 through the stomata and into the leaf, and non-photochemical quenching. Studies of the plants’ anatomy and hydraulics will improve understanding of the different species’ responses to variable environmental conditions. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.