Yesterday evening I went to the unveiling of 'Oliver's Bridge' in Porter Clough, on the western outskirts of Sheffield.
The event was organised by the Friends of the Porter Valley. Working with Sheffield City Council and a local stone mason, the Friends have restored an old packhorse bridge over the Porter Brook. They decided to name the bridge in honour of the renowned ecologist, Dr Oliver Gilbert, who was an active member of their group.
I regularly make use of one of Oliver's books The Ecology of Urban Habitats. Another, The Lichen Hunters, is on my 'to-read'list. He also wrote a number of thought-provoking articles in which he challenged received wisdom about invasive species and other ecological topics.
The last time I saw him, about 4 years ago, Oliver was examining the trunk of an ancient oak tree in Abney Clough - searching for lichens with a hand lens. Sadly, he died in 2005 after a long period of illness.