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Towards understanding complex plant-climate interactions and evolutionary patterns of life

Towards understanding complex plant-climate interactions and evolutionary patterns of life

Biogeographer T.D. Drezner standing beside a saguaro cactus at Kofa National Wildlife Refuge, Yuma, Arizona, USA.

Being in science and technology means to never stop asking questions, challenge the status quo, take your research to the next level, and lead others to follow their passions. Being a physical geographer means being part of a diverse background of knowledge and research, and inspiring future geographers through leadership and personal experiences. On February 11, we celebrate women in science and technology for their contributions to research and passion for teaching. Professor Taly Dawn Drezner is a biogeographer (studying the distribution of life) in the EUC Faculty with a specialty in plant-plant and plant-climate interactions, and disturbance.

Drezner has accomplished groundbreaking research in the field of biogeography, desert ecosystems, as well as complex plant-climate interactions. Her research found connections between the volcanic eruption of Krakatoa (now Indonesia) a century ago and the emergence of saguaro cactus, particularly in peripheral, marginal populations in the Kofa National Wildlife Refuge, Arizona. Sampling the age structure of the local cacti, Drezner estimated the ages of hundreds of cacti in several populations based on calculations of local growth rates using a model that she pioneered. Her findings illustrate the effects of climate change on species, demonstrating climate change at work.

Saguaro cactus flower

 “The saguaro are protected because they are a beloved symbol and icon of the desert,” Drezner affirms. “That a volcano elsewhere on the continent, or even the other side of the world, can so profoundly influence a local population underscores interconnectedness of ecosystems and our global climate,” she adds.

Her research in the Desert Southwest (Arizona, USA) looks at cactus demographics, facilitation, and responses to climate. Another current project includes looking at an endangered species of cactus at Point Pelee National Park in Ontario. She works directly with the Park to assist management with understanding its ecological limits, as well as aiding the Park’s conservation efforts. Here, she studies everything from its interactions with and dependence on other species, to microsite variations across its range.

Opuntia cactus, commonly known as prickly pear.

Drezner’s article on The importance of microenvironment: Opuntia plant growth, form and the response to sunlight  centered around the prickly-pear cactus group (Opuntia) that produce new stems, called cladodes, annually. Using three datasets collected over two field seasons, an assessment was made on pad orientation and tilt to quantify plant response to variations in receipt of sunlight for photosynthesis (photosynthetically active radiation or PAR). Results of the study confirm that the high variability in orientation in many populations is due to the lack of consideration of shade at highly local scales, and that even in open and sunny environments as Southern California, plants benefit from orienting photosynthetic surfaces to maximize PAR receipt that are critical to their functioning, growth and reproduction.

Drezner's dedication to teaching has inspired countless students to follow their passion in physical geography. York University students look to her as a role model and a leading professor in her field. She was awarded the Department of Geography’s Undergraduate Teaching Award in 2015 speaking to her commitment and dedication to impart knowledge and stimulate learning among her students. She teaches Physical Geography, Statistics, Desert Ecosystems, and Natural Disasters.