Using the past to unravel the future for Arctic wetlands

May 28, 2019

The Arctic is warming faster than any other region on Earth, which is causing the region's ecology to undergo a rapid transformation. Until now there has been limited information on the response of Arctic wetlands to climate change and rising global temperatures.

An international team of scientists led by the University of Leeds and the Geological Survey of Canada have reconstructed past moisture conditions and vegetation histories to determine how three main types of Canadian High Arctic wetlands have responded to warming temperatures over the last century.

Understanding past ecological changes in this region allows for more accurate predictions of how future changes, such as longer growing seasons and increased water from ground-ice thaw, could affect the wetlands.

The study, published in Geophysical Research Letters, found that under 21st century warming conditions and with adequate moisture, certain Arctic wetlands may transition into peatlands, creating new natural carbon storage systems and to some extent mitigating carbon losses from degrading peatlands in southern regions.

Study lead author Thomas Sim, PhD researcher in the School of Geography at Leeds, said: "High Arctic wetlands are important ecosystems and globally-important carbon stores. However, there are no long-term monitoring data for many of the remote regions of the Arctic - making it hard to determine their responses to recent climate warming. Reconstructing the ecological history of these wetlands using proxy evidence can help us understand past ecological shifts on a timescale of decades and centuries."

Study co-author Dr Paul Morris, from the University's research centre water@leeds, said: "Our findings show that these harsh and relatively unexplored ecosystems are responding to recent climate warming and undergoing ecosystem shifts. While some of these wetlands could transition into productive peatlands with future warming, the long term effects of climate change is likely to vary depending on the type of wetland.

"Although new productive peatlands may form in places such as the High Arctic, degrading peatlands in other areas are a major global concern. Every effort should be made to preserve peatlands across the globe - they are incredibly important component of the global carbon cycle."

The team examined ecological responses to twentieth century warming in the three types of High Arctic wetland: polygon mire, coastal fen and valley fen. Plant macrofossils and testate amoeba - tiny, single-celled organisms that live in wetlands - in combination with radiocarbon dating were used as proxies for historic changes in vegetation and moisture levels.

The study found that all three wetland types - with the exception of certain sections of the polygon mire - have experienced ecosystem shifts that coincided with an increase in growing degree days: a unit scientists use to quantify growing season length and warmth. The coastal fen site experienced an increase in shrub cover related to warming, while sections of the polygon mire increased in moss diversity.

The study also found that environmental factors other than warming temperatures may be contributing to vegetation changes. The research suggests that grazing Arctic geese may have contributed to the recent shift of from shrub to mosses in the coastal fen site. Arctic geese population have risen significantly and food competition at their summer nesting sites may be causing them to seek new grazing sites further north as they warm.

Study co-author Dr Jennifer Galloway, Associate Professor at Aarhus Institute of Advanced Studies, Denmark and Geological Survey of Canada, said: "Our study highlights the complex ways in which climate change is affecting ecosystems and suggest that effects of climate warming will vary depending on wetland type. While we can clearly see that climate change is altering ecology across the Arctic wetlands, whether that will result in a transition to productive peatlands will be strongly influenced by the complex dynamics that govern the wetlands."
-end-
Further information:

The paper, Pathways for Ecological Change in Canadian High Arctic Wetlands Under Rapid Twentieth Century Warming is published in Geophysical Research Letters 24 May 2019 (DOI: https://doi.org/10.1029/2019GL082611)

Full list of paper authors: Thomas Sim, Graeme Swindles, Paul Morris, Mariusz Ga?ka, Donal Mullan, Jennifer Galloway

For additional information please contact University of Leeds pressoffice@leeds.ac.uk or +44 (0)113 34 34031

Images:

Image 1_Canadian High Arctic coastal fen

Credit: Jennifer Galloway

Image 2_Canadian High Arctic polygon mire

Credit: Jennifer Galloway

Image 3_Canadian High Arctic valley fen

Credit: Jennifer Galloway

University of Leeds

Related Climate Change Articles from Brightsurf:

Are climate scientists being too cautious when linking extreme weather to climate change?
Climate science has focused on avoiding false alarms when linking extreme events to climate change.

Mysterious climate change
New research findings underline the crucial role that sea ice throughout the Southern Ocean played for atmospheric CO2 in times of rapid climate change in the past.

Mapping the path of climate change
Predicting a major transition, such as climate change, is extremely difficult, but the probabilistic framework developed by the authors is the first step in identifying the path between a shift in two environmental states.

Small change for climate change: Time to increase research funding to save the world
A new study shows that there is a huge disproportion in the level of funding for social science research into the greatest challenge in combating global warming -- how to get individuals and societies to overcome ingrained human habits to make the changes necessary to mitigate climate change.

Sub-national 'climate clubs' could offer key to combating climate change
'Climate clubs' offering membership for sub-national states, in addition to just countries, could speed up progress towards a globally harmonized climate change policy, which in turn offers a way to achieve stronger climate policies in all countries.

Review of Chinese atmospheric science research over the past 70 years: Climate and climate change
Over the past 70 years since the foundation of the People's Republic of China, Chinese scientists have made great contributions to various fields in the research of atmospheric sciences, which attracted worldwide attention.

A CERN for climate change
In a Perspective article appearing in this week's Proceedings of the National Academy of Sciences, Tim Palmer (Oxford University), and Bjorn Stevens (Max Planck Society), critically reflect on the present state of Earth system modelling.

Fairy-wrens change breeding habits to cope with climate change
Warmer temperatures linked to climate change are having a big impact on the breeding habits of one of Australia's most recognisable bird species, according to researchers at The Australian National University (ANU).

Believing in climate change doesn't mean you are preparing for climate change, study finds
Notre Dame researchers found that although coastal homeowners may perceive a worsening of climate change-related hazards, these attitudes are largely unrelated to a homeowner's expectations of actual home damage.

Older forests resist change -- climate change, that is
Older forests in eastern North America are less vulnerable to climate change than younger forests, particularly for carbon storage, timber production, and biodiversity, new research finds.

Read More: Climate Change News and Climate Change Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.