Muntjac deer.
And efforts to cull the animals are now being stepped up.
It is estimated that more than a thousand of the animals will be shot this year.
Malcolm Armstrong, wildlife ranger for the Forestry Commission and head of field operations for the Lincolnshire Deer Group, said that deer numbers had clearly grown year-on-year in spite of the cull.
Mr Armstrong said: "There is a continuing rise in deer populations and the damage is still extending.
"We have done some thermal imaging surveys and those show that numbers are increasing generally.
"The exact numbers are hard to gauge without long-term study, but there is an increased picture.
"As a largely rural county Lincolnshire has a lot more concentrated and arguably more important sites of botanical interest than other areas of the country.
"For some strange reason the deer seem to like to eat anything that is botanically rare!"
He said that muntjac deer in particular were harder to control than herding breeds such as fallow and red deer because they were solitary animals.
Muntjac can cause a particular decline in biodiversity due to their quick breeding cycle and preference for low-lying plants.
Greg Jones, central region liaison officer for the Deer Initiative, a partnership of deer management organisations, said that the muntjacs' tendency to browse rather than graze meant that they selectively destroyed the new-growth of plants.
"Their impact is quite significant, they nip up tips from fresh seedlings and the flower-heads of bluebells and other succulent plants," he said.
"The ancient woodland they browse can then start to get more grasses and monocultures, reducing biodiversity."
For the full story see Saturday's Lincolnshire Echo.