The groundbreaking research, in which Owen recorded every plant and animal in her suburban Leicester garden, will never be exceeded, said Dr Ken Thompson, speaking at the launch.
Owen found 2,673 plants and animals in her garden in her 1972-2001 survey, including 474 plants, 1,997 insects and 138 other invertebrates, as well as 54 birds and seven mammals.
Hoverflies numbered 43,749 from 1972-86 and 16,987 from 1987-2001. Butterflies were at 172 in 1973 but fell to 19 in 2001. Moths dived from 622 to 132 in the same years. Common wasps fell from 123 in 1972 to seven in 2001. Owen said non-native plants were surprisingly good at attracting wildlife.
Thompson added: "Those who regard natural history as another branch of stamp collecting are sniffy about gardens." But he said Owen’s book proved gardens’ value because her "ordinary" garden contained, for example, 56 per cent of all UK social bee species, 54.2 per cent of all UK ladybirds, 47.8 per cent of harvestmen species and 41.8 per cent of lacewings.
Owen said: "I had no idea [the survey] would go on for so long." She rued the "enormous decline" in insects spotted compared to "the glory years" of the 1970s.
Wildlife Gardening Forum chairman Dr Steve Head said funding should go to conserve declining common species such as frogs and habitats rather than rarities "collected like stamps" such as avocets and ospreys. He added: "We spend a lot on rare species but it makes very little difference overall."