The Chinese water deer is a non-native species that was introduced to Great Britain in the 1800s as part of a zoo collection. Following this, the deer was released as an ornamental park species and by 1944 had established small, localised feral populations in southern England.
Although non-native, the extent to which the Chinese water deer can be classified as ‘invasive’ is debatable. The species mostly inhabits wetland environments such as marshes, reeds, sedges and coarse grasslands. Within these ecosystems, its environmental impact is believed to be negligible due to low population densities grazing on ‘robust’ habitats. In terms of economic impact, the deer is known to graze on root vegetables and cereals but only when other food is scarce – another negligible impact.
Perhaps one of the most tangible negative impacts of the Chinese water deer is its contribution to annual road accidents. Deer collisions are known to be a large cause of road accidents every year, estimated to be 74,000 in 2007 alone. Road accidents are often concentrated in areas where there are high population densities of deer. Although the exact proportion of Chinese water deer accidents is unavailable, their low population densities make them unlikely to be the worst culprits.
One potential impact of the Chinese water deer, which has not yet been well researched, is its potential to act as a vector of spread for aquatic invasive plants in wetland areas (Mike Sutton-Croft, per comms). This has been observed to particularly be a problem in the Broads, where New Zealand pygmyweed has frequently been found growing in the middle of reed beds in areas unvisited by humans for a number of years. The plant is most often found growing on and adjacent to the deer tracks through the reed beds left by Chinese water deer. Although there is no conclusive evidence that the deer are spreading the plant, it is difficult to see how else the plant could be occurring in these areas.
So is this an ‘invasive’ species we control?
To further complicate the situation, Chinese water deer is currently listed as ‘Vulnerable’ on the IUCN Red List of Threatened Species. Although once widespread in it’s native range, the Chinese water deer population has become fragmented and isolated due to habitat destruction and high levels of poaching. Great Britain is now believed to hold 10% of the World’s population of Chinese water deer. Could this be one ‘invasive’ species we end up protecting?
Harris, R.B. & Duckworth, J.W. 2008. Hydropotes inermis. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <www.iucnredlist.org>. Downloaded on 10 December 2013.
Hu, Jie., Fang, S-G., Wan, Q-H (2006). ‘Genetic Diversity of Chinese Water Deer (): Implications for Conservation. Biochemical Genetics 44: 161 - 172
Photo Credits: Both GBNNSS