The headline commitment to require biodiversity net gain is welcome. It should be recognised, however, that the DEFRA and other metrics take no account of disturbance factors. The very presence of people is a deterrent to much wildlife, and cats are unnatural predators which unbalance the ecosystem. That being the case, it is important to ensure that a distribution of havens remote from severe disturbance is maintained, and that these do not lose their interconnections. In this respect ditches and hedgerows are important, and should be protected, as recognised in “Greater Cambridge Green Infrastructure Opportunity Mapping Final Report (2021)”. There are many recent examples of stretches of hedgerow being completely removed and replanted, whereas infill, retaining as much of the old hedge (including occasional trees) as possible, would be better for biodiversity.
In many ways, business or industrial developments have a greater potential for biodiversity gain than residential developments. There are few people around outside working hours, and there are no domestic animals. It is important that sufficient space is set aside within such developments, and that measures are put in place to ensure that it is managed in the future, as indeed mentioned in the Green Infrastructure, Proposed Policy Direction. A good example of what can be achieved is Granta Park.