Richard Death's recent Zoom talk to Guild members and visitors about Local Nature Reserves included the topic of Sites of Special Scientific Interest that are frequently referred to as SSSI, or even triple SI.
SSSIs are sites chosen for their wildlife and natural resources to be listed as special under the Wildlife and Countryside Act (1981).
The nearest SSSI to Stratford sub Castle is the River Avon SSSI that covers over one thousand acres. Details can be found on this page written by Kerry O'Connor, that was added to the village website last month SSSI in or near Stratford
The River system is explained in detail in Jim Platt's Stratford's Historic Water Meadows article
or view the images and description of The Stratford Water Meadows
The Walks page has details of a local walk along the river.