Why does the MWHG focus on this species?
As a species low on the food chain, water voles have developed many physical adaptations that defend them from predation, allowing them to move between land and water with ease. Two layers of fur and closable earflaps keep their skin dry and hearing intact. Proportionally large feet help them to swim, where as their long nails, although unsuited to swimming, can excavate extensive burrows. Their buoyant body creates a ‘plopping’ sound when they dive into water, alerting others of nearby danger, while brown-black fur camouflages them against the muddy water bed.
Kingdom: Animalia, Phylum: Chordata, Class: Mammalia, Order: Rodentia, Family: Cricetidae, Genus: Arvicola, Species: Arvicola amphibius.
Water voles live in ponds, rivers, canals, lakes and ditches with banks of firm soil that they can easily burrow into, such as our local clay. The low lying land of the Manhood Peninsula allow many of these habitats to keep a preferred slow yet constant flow of fresh water all year round, which protect the under water entrances to their burrows from predation.
Being a diurnal species (active during the day), water voles like to roam under the cover of densely vegetated banks, to stay hidden from predators such as mink, foxes, cats, adders and birds of prey.
The majority of a water voles diet composes of grasses, roots, herbs, winter berries and aquatic plants. As a staple of their diet, you will often see reeds with a trade mark ‘W’ shape or a sharp 45 degree angle bitten into them. The less appetising parts of the reeds will be left in a neat heap, known as a feeding station.
As a result of this natural, vegetarian diet their droppings are scentless, making them easily distinguishable from a rat’s. However, water voles have been known to eat frogs, snails and fish when desperate! In fact, up to 80% of water voles die every winter due to a lack of food resources.
With a short lifespan, of usually between 5 months and two years in the wild, it is an advantage for water voles to have many opportunities to reproduce. With the breeding season ranging from March to October, a water vole can birth five litters per year. Each litter can have between three and eight young. After just one month, they are ready to leave the burrow and breed.
To maintain healthy genetic diversity, water voles often move between other near by habitats, further a field from the other colonies on their own water way, to mate. The behaviour of colonies mating across a local area is known as meta populations.
Why does the MWHG focus on this species?
UK Biodiversity Action Plan: Priority Species (Nationally)
IUCN Red list: Least Concern (Globally)
Wildlife and Countryside Act 1981 (as amended): Laws safeguarding the water vole were updated in 2008, under section 9, to include full protection. This means it is illegal to kill, harm or disturb water voles. The obstruction or destruction of their habitat, as well as the removal of individuals from said habitat, is also prohibited.
Currently, around 160,000 new homes are being built in the UK each year, with the south coast seeing the most development. Green field sites are targeted by developers for being cheaper to build on, however this puts remaining fresh water habitats at risk of destruction. When a territory is removed, it can cause fragmentation between meta populations (colonies of water voles that interbreed across multiple habitats), which can dramatically reduce the overall health and numbers of the species.
Fortunately, ditches are easier to replace than other ecosystems, such as ancient trees, and should be created to reduce the impacts of habitat removal. Another concern of built up areas is the resulting increase in rain water run off due to impermeable, concrete land. This causes flooding, potentially killing water voles or making their habitat unusable during rainy periods.
Industry and Recreation
Water voles are very sensitive to intrusions into their space. Some farmers allow their cattle to roam freely into streams and ditches found on their land, which conflicts with water voles as the livestock eat most of the vegetation and trample the burrows beneath them. Chemicals from factories and farms, along with waste products of industry, often plastics, find their way into water habitats, harming the species itself or affecting its food source.
The Manhood Wildlife and Heritage Group clear polluted habitats to prevent water voles from abandoning their homes. Yet prolonged exposure to people, such as fisherman and walkers, or even regular mowing in park areas, can still stress a population into leaving. Wildlife reserves are vital in providing sheltered places for these susceptible species.
In the 1950’s, the American Mink (Neovision vision) escaped from fur farms and moved into the habitats of our native species. As an apex predator (with no predators of their own in the UK), the mink dominantly hunted the water vole population. With the ability to swim well, mink could deftly infiltrate the territory and under water burrows of their prey.
To counter the affects of this invasive species, the population must be maintained with trapping and lethal control, as governed under the Wildlife and Countryside Act 1981 (as amended). In the manhood peninsula, mink population levels are now kept at a low level, with the last account of a mink trapping here recorded in the winter of 2009.