Abstract
Rapid environmental changes induced plant species to modify their migration range to meet ecological tolerance. It mainly brought difficulties to slow colonizing forest understory species, because such changes already exceed their colonizing speed. The early life stage of a plant is particularly sensitive to the variation of temperature and light intensity. It is because this stage is more vulnerable than adults’ stage. We tested the effects of different temperature variation, light intensity and indirect effects of competition with other species on reproductive traits (the number of seeds, seed mass, germination rates, the number of germinated seeds) of Anemone nemorosa, a typical model plant of slow colonizing forest herbs, along an elevational gradients from sea level to 600 m. a. s. l in central Norway. The germination experiments were conducted in the growth chamber in the lab.
The results show that there is a positive relationship between cumulative temperature (calculated as Growing degree hours) and seed number but a negative relationship with seed mass. However, the cumulative temperature did not show any effects on germination rates. Accordingly, individuals under higher GDH produce many smaller seeds. Light intensity had significant positive effects on seed mass, germination rates, the number of germinable seeds, but had negative impacts on seed number. Hence, I conclude that at brighter sites, individuals create fewer bigger seeds with 81% germination rates and hence many germinated progenies. The weakest effects from competition release treatment might be because of the late removal of competitors or because the neighbor species are weak competitors for Anemone, since most of them were mosses.