Calls for a cull of grey squirrels in Cumbria are being considered.
Red squirrels are outnumbered in England by grey squirrels
The Lake District National Park Authority will look at the issue for the first time.
The move is a bid to protect endangered red squirrels which are under threat from grey squirrels.
The number of grey squirrels in England, which were introduced from North America more than 100 years ago, massively outnumber the red squirrels.
Jason Reynolds from the campaign group Red Alert said it is a tough but necessary decision.
Pass on disease
He said: "We are in an unfortunate situation here in the Lakes that we are now at the last stand of the red squirrel and we have to keep England's native red going.
"It's the last place it remains so the greys are not welcome because it is causing the extinction of the reds."
He said the problems are that grey squirrels compete with red squirrels for food and they also pass on disease to the reds.
He said measures to deal with the problem include creating areas of landscape which grey squirrels do not want to go into and then culling the grey squirrels.
Last year, plans to plant thousands of oak trees in Kielder Forest, in Northumberland, were scrapped in an effort to save red squirrels.
It followed a computer modelling programme which revealed planting oak trees would be the equivalent of building "motorways" along which grey squirrels could migrate.