Other species move northwards (or southwards) to take their place.
This process is happening again, and it is evidence of global warming.
"So much has happened to dragonflies in Britain since the 1990s that there is a most compelling case for the Government to adopt them as indicators of climate change", said Steve Brooks.
He is a London Natural History Museum research entomologist, with a special interest in the response of freshwater insects to climate change.
Ruddy Darter (Sympetrum sanguineum)
Dragonflies love warmer temperatures.
UK dragonflies have mainly stayed in the south of the country, until recently.
Since 1980, 34 out of the 37 British species of dragonfly have expanded their range northwards by an average of 74km.
That is over 2km per year..... nearly 6 metres per day.
For example, the ruddy darter (Sympetrum sanguineum) and the hairy dragonfly, (Brachytron pratense), have moved into north-west England.
This is yet more evidence that the UK’s climate is growing warmer.