How does climate affect plant traits?
The result of the work is, among other things, a map of the averages and the variability of the six plant species (maximum height, leaf area to leaf weight (SLA), seed mass, wood density, nitrogen and phosphorus content in leaves). Scientists then identified environmental factors that affect these traits. They found that in a warmer environment the plants are higher, they have larger seeds and leaves. Leaves are then larger in proportion to their weight. However, in case of herbs, the results were less obvious. An explanation may be that, for example, herbs have a greater number of life strategies than trees. They tend, more than trees, to settle smaller and more specialized niche environments. Herbs and trees were the most different in relation to the temperature differences during the season. The way to cope with unfavorable periods is probably a key factor responsible for the differences in the values of traits between these two growth forms.
What specific environmental conditions affect the values of plant traits?
It was mainly the average annual temperature, temperature seasonality and solar radiation, on the contrary, the seasonality of precipitation had the least impact.
Specifically:
- seed mass increases with increasing temperatures and the amount of precipitation
- wood density is higher at higher temperatures
- SLA decreases with decreasing temperatures and rainfall, but is higher at higher temperature seasonality
The last result may mean that a lower SLA in a colder environment serves to regulate the leaf temperature. Scientists first noticed that the content of nitrogen in tree leaves is correlated with temperature and sunlight. The results of this study are important for the emerging field of functional biogeography (a functional trait is any characteristic trait of an organism that affects its demography) and for future studies predicting the functional response of ecosystems to climate change. Plant woodiness must be taken into account in large-scale studies in order to adequately assess the importance of climate to plant traits. The results of this study explain the weak signals in previous studies, in which the trees and herbs were conceived as one group.
Other research steps in this field will most likely aim at combining plant trait maps with maps of ecological processes (e.g. remote sensing productivity data).
Radka ZELENÁ
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