The importance of poo on Stockbridge Down

A hornet robberfly on grass ar Stockbidge Down, Hampshire

There’s more to the average cowpat than you might think... The dung of grazing animals is an important feature of the habitat on Stockbridge Down, as it plays host to a variety of life. From the smallest dungfly to the rare hornet robberfly - a priority species on the UK Biodiversity Action Plan - there is an entire miniature ecosystem reliant on poo piles. Over 250 species of invertebrate find a home in the cowpats of the UK.

The hornet robberfly is a hunter, feeding on flies that are attracted to the dung of grazing herbivores. But if the grazing animals have been treated with insecticides such as avermectin for worming, this vital relationship suffers. Such treatments kill off any insects that feed on the dung, and this impact is felt up the food chain.

Grazing herbivore dung is also vital for coprophilous fungi. This is a particular type of fungi that grows on dung and has a special relationship with it. The fungi spores will be present on plant matter, which will then be eaten by a grazing herbivore.

The spores are built to survive the digestive tract of the herbivore, to end up in its dung – their very own little patch of compost. As a result, they flourish into fully grown fungi, which then releases spores onto the surrounding vegetation - and so the cycle goes on.

Some types of fungi thrive in dung
Fungi sprouting from horse dung
Some types of fungi thrive in dung

Dog poo, however, is a different story.  Grazing animals only eat vegetative material, and their dung will only contain nutrients already found in the area. Dog poo brings in rich, meat-based nutrients from outside the site.

Biodiversity comes from low nutrient soils. If dog poo is not removed, it will introduce excess nutrients to the soil, which allows dominant weeds and grasses to take over. Heathlands, rainforest and chalk grassland are all naturally low in nutrients and as a result have higher biodiversity; extra nutrients damage this.

Dog poo also plays host to several diseases that can cause harm to grazing animals and humans. Neospora causes abortion in cattle, sarcocystosis causes neurological disease and death in sheep, and toxocariasis can impact upon the liver, lungs, eyes and brain in humans: especially young children, who have more of a tendency to put their hands in their mouths and transmit the bacteria.