Effects of climate on phenology, flowering, and berry production of boreal forest understory plants

Abstract: Climate is changing faster than it was predicted before and consequently its impact is highly visible on many types of ecosystems globally. Effects of changing climate on forests and the environment are leading to threats for all sorts of ecosystems. Now the management of forests and decision making for environmental protection is following the trend of the impacts of climate change. Climate change is expected to affect plant and animal phenology. Phenological studies are a way to see how plants react to the changing climate. This study focused on this concept and tried to figure out the effects of climate on phenology, flowering, and berry production of four important boreal forest understory plants. Plant material was moved from colder locations (2-degree Celsius temperature difference) to three forest sites in southern, middle, and north Sweden. The potted plants were located in 10 different places at each site together with equally treated local plant material that served as a control. Sites used in the transplant experiment are from north to south: Tärnaby to Vindeln (northern Sweden), Idre to Siljan (middle of Sweden) and Tomtabacken to Vivarp (southern Sweden). For this experiment, the studied species were Solidago virgaurea L. (European golden rod), Vaccinium myrtillus L. (Billberry), Vaccinium vitis-idaea L. (lingonberry or cowberry) and Fragaria vesca L. (wild strawberry or woodland strawberry). Later, in the growing season, photos were taken of both provenances (cold provenance and warm provenance) in all three forest sites. This study aimed to find out translocation treatment effects for species-wise selected phenological traits. Finally, through image analysis considering selected phenological traits, this research has found strong treatment effects (at least at two sites out of three) for three phenological traits. DOY (day of the year) of first fruit development of F. vesca responded to the translocation treatment at Siljan and Vindeln. Again, DOY of seed setting and DOY of highest percentage of flowering of S. virgaurea responded to the translocation treatment at Vivarp and Vindeln. But, in most cases, no translocation treatment effects have been found for other phenological traits, and specifically for V. myrtillus and V. vitis-idaea, no treatment effects were found throughout this experiment which implies phenotypic plasticity. Absence of effects is an indication that these selected phenological traits would follow the effect of climate change through the adaptation process. This research work can be considered as a good reference for the phenology study of boreal forest understory plants, especially to know how studied phenological traits react to a translocation experiment with a temperature change, phenotypic plasticity and also to understand the change of phenology by climate change for above mentioned species.