Fragmentation of woodland (particularly ancient woodland), wetlands, and wildflower meadows is particularly harmful for invertebrate life. 97% of wildflower-rich grasslands in England have gone since the 1930s, similar losses have occurred in the rest of the UK.
There is a vicious cycle that magnifies the impact of fragmentation on small animals. Not only does it get harder for them to leave one fragment and find another to populate, eventually the likelihood of surviving dispersal attempts becomes very low, and over generations their wings and flight muscles shrink and they stop dispersing. Climate change may also drive reductions in dispersal ability. It is not surprising that around the world bumblebee distributions are shrinking; many can no longer survive in southern parts of their ranges, but are not able to move north. It also seems that the smaller the animal, the more severely habitat fragmentation reduces its dispersal ability.
Agri-environmental measures have been slow to reverse these declines in habitat extent and much of the action has been diffused across the countryside and not targeted in a structured or cost-effective manner.
Habitat restoration must be at a big scale – leaving field edges and corners to nature plays its part, and indeed helps to produce more robust and productive agriculture, but to adequately tackle the insectinction crisis and to restore wildlife to our countryside we must be far more ambitious – large areas of high-quality habitat must be created, restored and connected.
Wildlife-friendly habitat mosaics must be reinstated at a landscape scale, in some places ‘rewilding’ would help to create more varied and complex habitats that favour many insect species.
It is essential that habitat restoration creates networks for nature, otherwise we won’t achieve sufficient connectivity to save species from extinction.
We can stop, and reverse the global declines in our insects, but only if everyone pulls together to do their bit.
Small steps can have a huge impact if they all fall at the same time Five things you can do to reverse insect declines