More barbs in more places, that’s the power of AT&T(histle)
Written and edited by Nicole Read and Suvi Birch
Summary
Several studies have shown that invasive plants are likely to grow larger and more competitive with climate change (see Liu et al. 2017). However, the phenological or physiological shifts that lead to larger size is often unknown. Thus, two plants may both grow larger due to climate change but for different phenological reasons. Understanding what shifts lead to larger plants could better inform the type and timing of invasive plant management. In this study, Zhang et al. compare the seasonal growth patterns of two invasive thistles, Carduus nutans and Carduus acanthoides, both of which grow significantly taller with warming temperatures. For C. nutans, warming shifted the timing of growth earlier, which led to faster growth after bolting but before flowering. For C. acanthoides, there was no change in the timing of growth, and the fastest growth occurred after flowering. While both plants experienced similar increased height, enhanced growth occurred at different life stages.
Take home points
Plant height highly influences plant population spread rate, particularly in plants that use primarily wind dispersal. A 9% increase in height leads to a 70% increase in population spread rates in the thistles studied.
Both thistles grew taller with warming, but the fastest growth rates occurred at different times in their growing cycle.
Management implications
Thistles were taller under warming than under ambient temperatures, which means they’ll both likely spread faster.
Managers should expect changes in the duration of life stages (germination, bolting, flowering) of thistles under climate change, but not necessarily in the same way for all species.
Keywords
Shifting seasons; Phenology; Growth rate; Invasive plants; Carduus nutans; Carduus acanthoides