[Research Stories] Climate change studies

How does climate change affect alpine vegetation and plants?

SDGs: 13. Climate Change, 15. Life on Land

Targets:

13.3: Improve education, awareness-raising and human and institutional capacity on climate change mitigation, adaptation, impact reduction and early warning

15.4: By 2030, ensure the conservation of mountain ecosystems, including their biodiversity, in order to enhance their capacity to provide benefits that are essential for sustainable development

Climate change is the most urgent issue since we have encountered impactful consequences in the past few decades, such as strong typhoons, extreme rainfalls, and even hot winters. Dr. Cheng-Tao Lin from the Department of Biological Resources leads a team to enter the heart of Central Mountain Ranges and Hsueh-Shan Mountain Ranges to monitor the influences of alpine summit vegetation induced by climate change. This project is funded by Forestry Bureau and has continued for over a decade. The former project investigator Dr. Ho-Yi Liu (National Sun Yat-sen University), who initiated this project, has surveyed many summits in Taiwan and established preliminary monitoring sites following a standard procedure named GLORIA (Global Observation Research Initiative on Alpine Environments) multi-summit approach. The data collected through the past three resurveys showed a significant temperature increase among the high-mountain summits in Taiwan. Dr. Lin’s team also found there was a declining tendency of water balance because the potential evapotranspiration significantly increased from 2014–2019.

Landscape view of high mountains in Taiwan. Photo by Yu Su (蘇昱).

Investigating alpine plants (North Peak of Chilai). Photo by Dr. Chu-Chia Kuo (郭礎嘉博士)

Since most of the hypotheses assume the species of lower altitude would migrate to higher altitudes when the temperature increases. Thus, they have also applied two indicators, thermophilic and moist-philic, to examine the changes in vegetation composition in alpine summits. The concept of the thermophilic indicator is trying to combine the climatic niche levels of thermophilic species and their percent coverage in the target summits during different periods. In other words, if the thermophilic indicator showed a positive and increasing value, we could interpret that the species of alpine vegetation were mainly composed of species preferring warm climates. Compared to the climate change studies on alpine vegetation in Europe, most of the studies showed increased thermophilic values.

Nevertheless, the results of Dr. Lin’s team did not have significantly increased thermophilic values. Only a few mountain summits showed a similar effect, while a summit showed negative values. However, plant biodiversity decreased during the past decade, and it was pretty different from the studies from Europe. It might be due to the water balance in the alpine summits. Therefore, Dr. Lin’s team integrated statistically downscaling climate data derived from European Centre for Medium-Range Weather Forecasts (ECWMF) and vegetation data to calculate the moist-philic index and determine if the vegetation responses were affected by water. The results revealed that some summits significantly decreased moist-philic values, implying that the alpine summit habitats would encounter water deficiency.

Through their long-term monitoring and analyses, we could find the climate changes effects on high mountains and should take further actions to protect and conserve our alpine plants. The ratio of endemic species on these mountain summits is approximately 50%! Most of the plants have been limited to isolated and small sites in Taiwan. Their studies can also support the conservation policy, especially the rare and endemic species in the alpine summit habitats.

[Research Stories] Climate change studies

How does climate change affect alpine vegetation and plants?

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