Close to the City of York in North Yorkshire, Strensall Military Training Area is a 579 hectare Site of Special Scientific Interest (SSSI), which along with fellow Flagship site Skipwith NNR, is one of only two extensive areas of open heathland in the Vale of York.

The site supports a rich mosaic of habitats including mire, ponds, woodland and acid grassland.

As the majority of the common is owned by the Military of Defence, the period of military occupation from the 1880s onwards has helped to create many of the ponds including several excavated in recent years for conservation purposes. Some of the oldest ponds however, probably originated as peat cuttings and clay pits.

One of the oldest ponds on the common, Kidney Pond, which certainly existed in the 1890’s, is an extraordinary pond as only around 5% of the original pond area, as seen in 1890’s mapping, exists as a crescent shaped area of open water. The majority of the basin is now occupied by possibly the best and most extensive examples of nationally rare floating fen habitat in lowland England. The remaining open water to the south contains several Nationally Scarce plant and invertebrate species, including Tubular Water-dropwort Oenanthe fistulosa, Marsh Stitchwort Stellaria palustris and Pond Mud Snail Omphiscola glabra. Pond Mud Snail is a rare and declining wetland mollusc. Historically, this species was widespread throughout lowland areas of England and Wales. Although possibly under-recorded, it is thought that this species has undergone a marked decline in the last 50 years and it is now classified as vulnerable (IUCN).

Located close to Kidney Pond, the Pillwort Scrape is an open, shallow pool excavated in 2012. This is a shining example of how newly created ponds can quickly become rich aquatic habitats. In just a few years, over 100 plant and invert species have been recorded in and around the pond, including Nationally Scarce Pond Mud Snail and Pillwort Pilularia globulifera. Pillwort is a very distinctive little grass-like plant. It is in fact an aquatic fern with thin, threadlike leaves which unfurl from tight coils as it grows and produces hard spore cases ‘the pills’. In the right conditions it forms a creeping mat over bare mud at the margins of ponds and lakes which can look like a miniature bright green lawn. Pillwort is a Priority Species for conservation in both England and Wales. It is declining rapidly throughout its north-west European range and the UK now holds a substantial proportion of the global population.

World’s End, to the East of Strensall Common, is a Site of Importance for Nature Conservation (SINC), with a mosaic of fen meadow, acidic grassland, heathland and pond habitats. Managed by the Forestry Commission, the site is particularly well known for dragonflies. As well as the five common species of damselfly, both species of Red-eyed Damselfly Erythromma Najas and Erythromma viridulum are breeding making the site one of the most northerly in the UK for these species. Many of the commoner species of dragonfly occur including Brown Hawker Aeshna grandis, Common Hawker Aeshna juncea and Ruddy Darter Sympetrum sanguineum.