Some dragonflies are thriving in a warmer climate

Germany has a range of suitable habitats that make it a hotspot for dragonflies and damselflies. Many of these species are suffering from habitat loss and degradation, but not all of them, according to new research from the German Center for Integrative Research (iDIV). 

While a growing collection of studies have found evidence of long-term population declines among dragonflies and damselflies throughout Europe, the new study suggests that some species are thriving in a warmer climate.

In collaboration with experts at FSU and UFZ, the iDIV team conducted a nationwide analysis of the occurrence and distribution of dragonflies and damselflies in Germany between 1980 and 2016. 

The study involved over one million occurrence records for 77 species from different regional databases, most of which were collected by citizen scientists.

The researchers determined that dragonfly and damselfly populations have experienced both losses and gains. The largest number of decreases were observed in cold-adapted species that prefer standing water habitats such as bogs and fens. Many of these species are already threatened with extinction. 

“These species are suffering a lot from habitat loss and degradation. Here, we are still facing serious conservation challenges,” said study first author Dr. Diana Bowler.

Overall, the analysis suggests that cold-adapted species in standing water habitats are likely to be most vulnerable to climate change and other environmental changes. 

Overall, the experts found increases in the occurrence of 45 percent of all species in warm-adapted species. 

“Formerly rare species such as Crocothemis erythraea and Erythromma viridulum have become much more common across Germany,” said Dr. Bowler. “These species prefer warmer temperatures and so their increase in Germany is most probably an outcome of long-term climate change.”

The most population gains were found among running-water species, which represents the conservation success that can be achieved by better environmental management. 

“The increase of these species reflects a recovery from the impacts of past water pollution and the almost complete destruction of natural floodplains,” said Klaus-Jürgen Conze. 

In Germany, projects were initiated in the 1990s to improve freshwater quality and river restoration. Furthermore, the EU Water Framework Directive was adopted in 2000.

“Our study highlights the great value of these monitoring efforts for assessing changes in species’ occurrences,” said study senior author Professor Aletta Bonn. “We found some signs of accelerating declines in the last decade, which highlights the need to support the efforts of these societies in the future.”

The study is published in the journal Diversity and Distributions.

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By Chrissy Sexton, Earth.com Staff Writer