Plant Responses to Climate Are Lagged
Plant responses to climate drivers such as temperature and precipitation may become visible only years after the actual climate event.
This is a key result of new research led by the German Centre of Integrative Biodiversity Research (iDiv), the Martin Luther University Halle-Wittenberg (MLU) and the Helmholtz Centre for Environmental Research (UFZ) published in Global Change Biology. The results indicate that climate drivers may have different effects on the survivorship, growth and reproduction of plant species than suggested by earlier studies.
Two in five of the world’s plant species are at risk of extinction. In the face of climate change, understanding why certain plant species are vulnerable to extinction while others prevail is more urgent than ever before. Previous studies linking climate and plant vital rates have found relatively modest effects, sometimes leading to the conclusion that other threats, such as land use change, may still be more important than climate drivers. However, these conclusions could result from wrong assumptions about which times of the year (which “time window”) climate drivers such as temperature and precipitation influence plant species. “Most researchers assume that plant populations respond to the climate within twelve months and only use this time window in their models to analyse plant responses,“ says first author Sanne Evers from iDiv and MLU.
Climate conditions during dormant seasons often neglected
For their study, the team of researchers led by iDiv, MLU and UFZ analysed 76 studies performed on 104 plant species that link climate drivers with demographic responses. They found that 85% of all studies considered 1-year time windows, and often focus on the growing season (e.g. spring and/or summer). However: “There are many ways in which climate during the dormant season, or climate that occurred few years in the past, can influence the survivorship, growth, and reproduction of plants. For example, species can grow substantially during the cold season, at least where the cold season temperature does not fall below 5° Celsius. In addition, it might take multiple years for plants to die after physiological damage from drought has occurred,” says Aldo Compagnoni from iDiv and MLU and senior author of the paper.