The demise of alpine plant specialists? Implications of warming temperatures and advanced snowmelt on alpine plant communities, southwestern Colorado

Background/Question/Methods

Climate change is producing warmer temperatures in the west resulting in drier conditions and an increase in dust storms resulting in dust deposition on the snowpack in mountainous regions. These phenomena may have extreme effects on alpine plant communities as species with broad distributional ranges, generalists, may out compete alpine specialists as climatic conditions shift. We used snow manipulation fabrics to mimic radiant forcing from dust and artificial open top warming chambers to mimic warmer growing season temperatures.  We measured plant behavior based on key phonological events such as first leaf and first open flower, first seed, and first leaf color change. We tracked plant phenology changes through the fall until first snow and quantified the data in SPSS using a repeated measures general linear model. 

Results/Conclusions

Our results show that there was a significant variation in the response of generalists compared to specialist to the effects of warming in terms of when species first flowered and went to seed (p=0.011; p=0.023). This phenomena replicated over multiple years may result in dramatic shifts in species composition in alpine environments. If generalists spend more time in flower than the specialist then interactions with pollinators varies and overall reproductive success becomes higher for generalists. This may result in the crowding out of specialist species creating less biodiversity in alpine environments. Understanding these responses is important for land managers in all reaches of the Colorado Plateau if we wish to preserve the biodiversity of sensitive alpine environments.