June 2025
My wife and I are currently in France. It is early May as I write. Summer here is experienced several weeks earlier in Aquitaine than it is in Sussex. The wheat and barley have already formed their seed heads, and the weather is very summery. We went for a walk this morning and encountered at least 5 European brown hares (Lepus europaeus) chasing each other and running across fields. Plus, several species of orchid in flower. We also identified several birds calling/singing to mark their territories; these included a black woodpecker (Dryocopus martius), golden oriole (Oriolus oriolus) and nightingale (Luscinia megarhynchos).
The environmental scenario that generates the highest biological diversity, as here, is habitat diversity, such as a mix of woodland, grassland, heathland, wetland and arable. This has also been the tenet of good gardening, and this is what we are trying to generate on our patches in both England and France. However, the two ecosystems are strikingly different. The human population density of Britain is about double that of France. Also, Great Britain is an island, but France is part of a giant continent stretching from the Atlantic Ocean to eastern China on the Pacific Ocean coast. Much of this land has not been modified by humans. Many species cannot or will not disperse across water, so Britain’s biodiversity is always going to be isolated and limited. Most of it became trapped when the Channel separated Britain from the continent about 6,100 BC. Then, Britain became an archipelago of offshore European islands that broke free of mainland Europe for good. This was during the Mesolithic period – the Middle Stone Age. There are relicts of a human Mesolithic settlement located NW of Uckfield spanning what is now West Park Local Nature Reserve and Lake Wood Woodland Trust reserve.Here Mesolithic rock shelters can be seen and about 10,000 flint tools have been found. Many of these people would have been the ancestors of truly British people still living.
Island populations generally have lower species diversity than continents, but also generate endemic species that are found nowhere else. For example, I have been studying blue tits (Cyanistes caeruleus) for many years, and the British population of this bird (C. caeruleus obscurus) is a sub-species unique to Britain. Also, the Canary Island blue tits have generated 4 further populations of distinct species (not sub-species) of blue tits (C. ombriosus, C. degener, C. palmensis and C. teneriffae). Their ancestors initially came from Africa, and before that from China where true blue tits no longer exist.
Back to France, and our walk. We were also delighted to see a large green and blue lizard (Lacerta bilineata), posibly Eurasia’s largest and most striking lizard. Later, we saw one of these running, dinosaur like, across our front lawn.