Encountering deer is a thrilling experience. Whether it’s fawns frolicking in the spring sunshine, or bucks locking horns in battle, these majestic animals have been a favourite of the general public and royalty alike for centuries. But could there be a darker side to the story of deer in the UK?
Since 1999, their population has doubled, with an estimated 2 million deer now roaming our parks and countryside. Usually, the successful breeding of wildlife calls for celebration, but when a population expands out of its ecological niche, the effect can be disastrous. Causing an estimated 74,000 road accidents annually and charged with the spread of Lyme disease, deer are becoming increasingly problematic for humans. But it is their potential impact on the environment which is the most alarming.
Not only have deer caused an estimated £4.5million worth of damage to woodlands in recent years, but the growth in their population has had an adverse impact on our birds. Deer overgraze woodland, demolishing the understory layer of vegetation which birds are dependent upon for nesting and foraging. According to the British Trust for Ornithology, Nightingales and Willow Tits are two of the birds most catastrophically affected by the presence of a large number of deer. Coinciding with the growth of the deer population, these bird species have seen a decline in their numbers, and some studies even suggest that there are 50% less wild bird species where deer are present. Why does this matter? In fact, birds are integral to a functioning ecosystem. As well as maintaining sustainable levels of both their prey and predator species, they are also vital in plant reproduction, dispersing seeds and pollinating flowers. Undoubtedly, the deer population must be controlled before their impact on birds is irreversible.
What has caused this explosion in the number of deer? Firstly, the UK is currently home to six species of deer, but only two of these are truly indigenous. The other four were introduced from abroad and their population has steadily grown since. For example, there are now 11,500 Sika deer and over 40,000 Muntjac deer in the UK. Secondly, the 1963 Deer Act provides a close season when hunting these ubiquitous creatures is strictly prohibited. Although this act is laudable from an animal welfare point of view, to consider the protection of a species in isolation is too simplistic. In order to truly protect wildlife, we must consider how species are interconnected and their relationship with their surroundings. Furthermore, one significant reason for this explosion in deer population is the lack of natural predators. British forests were previously home to wolves, lynx and bears, all of which have now been driven to extinction through persecution and hunting. This is illustrative of how removing one link in the food chain causes it to crumble.
Sadly, this issue is not specific to deer or to the UK. On the opposite side of the world, Australia are facing similar threats to their world-renowned reefs from the crown-of-thorns starfish. With a single adult able to consume up to 10m2 of coral per year, these nocturnal creatures have become one of the leading causes of reef degradation in the Indo-Pacific region. Their presence should be perfectly sustainable, but the region has seen a rise in ‘outbreaks’, in which the starfish population suddenly explodes, and they consume the coral at a faster rate than it can grow. The starfish’s predators have been removed by overfishing, just as the deer’s have in the UK. Funded by money from tourism, teams of divers are sent to systematically cull the crown-of-thorns. Like the deer, these sea creatures, who are simply fulfilling their natural role, have become a plague upon their own environment.
Crown-of-thorns starfish outbreak on the Great Barrier Reef via @aims_gov_au on Twitter