The findings, which also include two prosecutions in the past year, have been revealed as The Royal Parks warns about the damage caused by foraging for mushrooms.
With the wet and mild conditions continuing throughout this autumn, ecology experts are worried that eco-systems and food for wildlife is being stripped from the parks by those preparing special meals and dinner parties.
Autumn is a peak time for the growth of mushrooms, the visible part of fungi. During this time they produce and disperse spores to reproduce.
Royal Parks ecology head Julia Balfour said: "Picking the mushroom does not kill the fungus, but can hinder reproduction and therefore diminish the population. Mushrooms are an important food source for many animals in our parks, and they are host to some rare species of invertebrates including those associated with ancient trees.
"They are also a beautiful addition to the landscape of the Royal Parks with 400 species of fungi in Richmond Park alone."
Andy Overall from the London Fungus Group said: "Due to the natural and historic nature of the Royal Parks many rare and in some cases endangered species of fungi thrive among acid grasslands and ancient oaks.
"With the number of people foraging fungi in the Royal Parks thought to be on the rise, this will no doubt have some impact on the fabric of the parks, be that an impact on the habitat, the other animals and insects that use the fungi, or our enjoyment of seeing the fruitbodies of some of the more spectacular fungi. Larger fungi are for all people to enjoy, not just the few. "
Pc Paul Barber from the Royal Parks Operational Command Unit of the Metropolitan Police said: "We’ve noticed a steady rise in mushroom foraging over the years which could possibly be attributed to celebrity chefs’ endorsement. In some cases, we’ve caught individuals with enough mushrooms to fill a small dustbin."
Caroline Hobart, Chair of the British Mycology Society's Field Mycology and Conservation Committee, the leading UK Mycological society dedicated to the promotion and education of the science of fungal organisms and processes, said: "We are delighted that the Royal Parks take the protection of fungi so seriously. All too often the fungal kingdom is neglected in management, we therefore applaud any organisation that considers protecting fungal organisms which have been assessed to be endangered or over exploited."