Indirect climate change impacts on alpine plant communities

Informations

Funding country

Norway

Acronym

-

URL

-

Start date

1/1/2018

End date

12/31/2022

Budget

1,219,914 EUR

Fundings

Abstract

Mountain areas provide important habitats for many plant and animal species, but they also contribute with important ecosystem functions and services such as carbon storage, areas for livestock grazing, and regulation of floods and landslides. At the same time, mountain ecosystems are particularly vulnerable to climate change. Climate change is already causing significant alterations in alpine biodiversity, including range shifts to higher elevation and latitude and changes in biodiversity and ecosystem functioning. It is unclear, however, to what extent these responses represent direct effects of altered climate, or indirect effects mediated by changing interactions among species. Entirely novel interactions, which arise because species do not migrate in concert, could have especially large impacts on species, community and ecosystem responses to climate change, especially if newly arriving species introduce novel functional traits and trait combinations. This possibility has until now received little attention in climate change ecology. We investigate these issues using field experiments. In the summer of 2018, we moved competitive lowland species up into the mountains, with and without artificial heating, and we are now following up the effect of these species on vulnerable alpine species. After three years, we see that the transplanted lowland species survive in the mountains, but they do not set mature seeds, and seeds sown in the mountains germinate poorly and seedlings harve high mortality. This indicates that the climate is currently not warm enough for them to be able to survive in the mountains. They grow and survive better under experimental warming, but they still do not succeed in reproducing from seeds. Over the final project year, we will study how the transplanted species affect their neighbouring mountain plants, and if these effects are stronger with experimental heating. We will also investigate the effects of lowland plants with and without heating on the ecosystem's carbon storage. Climate change leads to warming, but also to more variable weather. Drought in the spring could have dramatic consequences for the alpine species' seed germination. We have tested this in a lab experiment. We find that plants from rainy regions tolerate drought less well than plants from dry regions. This means that mountain plants in oceanic areas can be more affected by extreme weather in the form of drought than mountain plants in continental areas. Using data from a global network of collaborators, we have harnessed data from existing plant community transplant experiments from around the world, and we are now relating patterns of colonization and extinction in these experiments to biotic and abiotic characteristics of the study region. The transplanted lowland specis are able to survive in the alpine, both with and without warming, but they do not set ripe seeds and are not able to regenerete from sown seeds. This suggests the climate is not yet warm enough for them ot successfully colonize alpine areas. Over the next two years we will assess how the planted lowland species are affecting the alpine plants and biodiversity. INCLINE collaborates with the EMERALD project to explore the consequences of our findings, especially regarding carbon dynamics, using the land surface model CLM-FATES. This enables upscaling of consequences to understand climate feedbacks from alpine ecosystems. The results of our studies are also being used in model simulations to predict the consequences of climate and climate change for biodiversity on a larger scale and under different future climate scenarios. INCLINE thus contributes to better understanding of the underlying mechanisms and to improved predictive models that can incorporate impacts of changing species interactions on range dynamics under climate change.