April 19, 2023

12:00pm, PST 1100 TLSB and Zoom

Louis Santiago
University of California, Riverside

" Drought survival strategies of tropical trees "

Tropical forest responses to drought can range from minor alterations of matter and energy fluxes to the atmosphere, to major mortality events. The drought responses of the tropical forest plants that lead to forest-wide responses are notoriously difficult to predict because of high species diversity and the episodic nature of drought. Yet, proper representation of tropical forest in Earth system models are critical for understanding the imprint of past droughts and forecasting the effect of future droughts on global carbon cycling. We propose a framework in which coordination of drought survival traits is evaluated to determine whether particular traits co-occur repeatedly in species to form recognizable drought survival strategies. The traits that tropical woody plants use to survive drought include:  1) cavitation-resistant xylem, 2) capacitance, 3) drought deciduousness, 4) deep roots, 5) regulation of gas exchange, 6) photosynthetic stems, 7) regulation of osmotic potential, 8) low cuticular conductance, and 9) water storage tissues and organs. We evaluate the repeated co-occurrence of particular traits and identify several strategies that may be considered classes of drought survival mechanisms. We further hypothesize that species exhibiting particular assemblages of drought survival traits may show contrasting responses during drought. Overall, our data provide a way forward for understanding the value of particular traits within the context of coordinated strategies and may provide a simplified pathway for predicting drought responses of thousands of unmeasured tropical woody species.

Host: Lawren Sack