Plantwatch has successfully revived abandoned ponds, allowing dormant seeds to germinate once again.

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In the past, ponds were commonly found on farms and were home to a variety of aquatic plants and animals. However, over time, many of these ponds were drained and filled to make room for more intensive farming practices. As a result, these ponds were abandoned and forgotten. However, it is possible to restore these “ghost ponds” by reviving the seeds of plants that have been buried in the sediment for many years. These seeds can lay dormant for decades or even a century under fields of crops.
Sometimes, hints about these abandoned ponds can be found as wet indentations on the earth, unhealthy plant growth, or through historical maps. Research conducted by University College London (UCL) has demonstrated that these ponds can be revived by digging them up to uncover the original pond floor, and then allowing rainwater or groundwater to replenish them. When exposed to sunlight and oxygen, seeds preserved in the old sediment have the potential to sprout, and within a year, the pond’s ecosystem flourishes once more, including aquatic creatures.
Rare plants that were thought to be extinct in multiple areas have been revived. One of these plants, the grass-poly, had not been observed in Norfolk for over 100 years. However, in 2020, Professor Carl Sayer from UCL found its lovely pink flowers growing in a recently restored pond.
Source: theguardian.com