If you think autumn and spring seem different now compared to how they used to be, you’d be right.  

New University of Canterbury research explores the impact of disruptions to Earth’s seasons caused by climate change.

New Zealand research published in the prestigious Science journal explores the impact of disruptions to Earth’s seasons caused by climate change.

These changes could have far-reaching consequences for the world’s biodiversity, according to the new ‘big-picture' study led by Te Whare Wānanga o Waitaha | University of Canterbury Science PhD student Daniel Hernández-Carrasco. 

His research has uncovered mounting evidence for the widespread ecological consequences of Earth’s changing rhythms due to climate change and other human impacts.  

“Disruption caused by climate change and other human-related stressors such as dams and deforestation is shifting the timing of seasonal events, heightening seasonal fluctuations, and making the seasons less predictable across the years,” Hernández-Carrasco said.

“This is affecting natural processes such as tropical monsoons, the timing of mountain snowmelt, and the annual migration of millions of animals. We’ve found that all these factors could have significant and unexpected consequences for biodiversity.”

He said the new research is unique because it explores the cascading impacts of disruptions to seasonality from the micro level of genes up to the macro level of entire ecosystems.

“It’s clear that seasonality is changing around the world and with that will come ecological consequences. What our research has emphasised, though, is that the impacts of these changes could be more severe than previously thought, because the effects can amplify from individuals through to whole ecosystems.

“We show that changes in migration patterns can result in the restructuring of whole food-webs and seasonal changes will affect the genetic diversity and life cycles of populations, triggering major consequences across biological and ecological systems.” 

UC School of Biological Sciences Associate Professor Jonathan Tonkin, who supervised and co-authored the research paper, says seasonality is a foundation to the environment as we know it, from tropical forests to the ocean floor. 

“Seasonal fluctuations determine cyclic changes in environmental conditions, including temperature, daylight hours and rainfall. Because species have evolved adaptations to cope with, and even benefit from these rhythms, disrupting them poses a threat to Earth’s ecosystems and human society alike, with downstream effects on food security and the control of diseases.”

Associate Professor Tonkin said the study, co-written with UC School of Biological Sciences Professor Jason Tylianakis and Professor David Lytle from Oregon State University, has synthesised existing research across diverse disciplines, finding connections among responses to seasonality that have previously been overlooked. 

“We know that climate change and other stressors such as river damming are altering natural seasonal cycles. However, we may have underestimated the consequences of these changes.” 

The new findings highlight that a framework is needed to account for the effects of changing seasonal fluctuations on species’ ecology and evolutionary processes across all levels. This would allow more robust forecasts to be made, he said. 

The research was supported by Associate Professor Tonkin’s Rutherford Discovery Fellowship from the Royal Society Te Apārangi, while Hernández-Carrasco received funding from a UC Doctoral Scholarship.