As global warming alters ecosystems, the need to predict the reorganization of Earth's biodiversity has become urgent. New research, published in the Proceedings of the National Academy of Sciences of the United States of America May 20, suggests that neglecting the ecological differences between male and female plants can lead to inaccurate biodiversity forecasts. The study led by Jacob Moutouama , a postdoctoral research associate at Rice University and lead author, highlights the need to refine biodiversity forecasts to account for the sex-specific responses to Earth's rapidly changing climate.
Many plant and animal species are dioecious, meaning they have distinct male and female individuals. Traditional biodiversity models often overlook this distinction, potentially missing key differences in climate sensitivity. The research team conducted field experiments and developed mathematical models for the dioecious plant species Texas bluegrass (Poa arachnifera) to explore how sex-specific traits affect the species' ability to respond to environmental change.
"Tracking both sexes can be twice the work, which is why most ecologists don't do it. But our findings show that failing to account for the dynamics of both sexes could underestimate species' vulnerability to climate change," said Tom Miller , associate professor of biosciences who supervised the research.
Modeling female and male responses
The researchers created two modeling frameworks: a conventional female-dominant model and a new two-sex model that incorporates feedback between sex ratios and reproductive rates. Through common garden experiments across Texas, Kansas and Oklahoma, they assessed how climate sensitivities differ by sex and how this affects future distribution.
Both models predicted a poleward shift in suitable habitats under future climate scenarios, but the female-only model underestimated this shift. While female plants tolerate a wider range of temperatures, populations with more females may face reduced reproduction due to limited mating opportunities.
This research addresses a gap in ecological forecasting — assuming that male and female individuals respond similarly to environmental stressors. Integrating field data into mathematical models is essential for enhancing forecast accuracy, Miller said.
"It turns out that collecting demographic data across an entire species range is incredibly challenging, which is likely why few have attempted this before," he said.
Conservation implications
The findings suggest that for dioecious species such as Texas bluegrass, "the future is female," according to the study. Global warming may increase female dominance, challenging previous studies that predicted male advantages. Understanding these sex-specific climate responses could lead to better conservation strategies for vulnerable species.
Neglecting sex structure could undermine efforts to maintain healthy ecosystems, underscoring the complexities of population biology that affect species survival, Moutouama said.
"Understanding the real-world complexity of population structure helps us anticipate and prepare for changes in biodiversity," he said.
The study, co-authored by Aldo Compagnoni of Martin Luther University Halle-Wittenberg, received support from the National Science Foundation Division of Environmental Biology.
