28th July 2016
Capability Brown landscapes, and what beetles say about continuity
Many of the UK’s richest sites for wood-decay beetles are those which were influenced by Capability Brown. In this 300th anniversary year of the landscaper’s birth, Keith Alexander, ATF trustee and ecological consultant, considers why saproxylic beetles often thrive in Brown’s landscapes.
Wood pasture and parkland was the original ‘Wildwood’ which developed following the last Ice Age. We have evidence of this from the subfossil beetle fauna which shows that 28% of beetles known from the Wildwood period are species of open grassland, while 13% are tree canopy species and 47% are saproxylic (dependent on dead and decaying wood), but a mere 2.5% are shade-demanding species. This demonstrates that trees and open grassland, grazed by large herbivores, were the predominant vegetation cover, rather than closed canopy woodland.
Species like the black-tipped cardinal click beetle Ampedus elongatulus, which is associated with large open-grown oak trees, are likely to be found in the types of parkland typical of Capability Brown landscapes, like Wimpole (pictured above) because they still provide this open grassland habitat of the Wildwood period. It therefore appears that habitat continuity is the key factor here. Eighteenth century landscaping did not impact significantly on saproxylic species richness, because medieval wood pastures lent themselves to enclosure as deer parks, which became the landscape parks of Brown’s schemes.
Decaying wood in living trees is the most important habitat for saproxylics, and standing dead trees and fallen deadwood also provide valuable habitat. In the early stages of decomposition for example, white-rotted heartwood is commonly fed upon by larvae of the rhinoceros beetle Sinodendron cylindricum (pictured below). Brown’s contribution to the conservation of wood pasture habitat and wood-decay species included the retention of many old trees – to maintain an air of antiquity – but also new plantings. In this way he contributed to a mixed age structure of tree populations, and maintained landowner interest in parkland management. Brown clearly liked old trees; he valued having old and stag-headed trees in his landscapes, and used standing dead wood as a feature. His own watercolours show delight in the careful detail of dead branches on old trees.
It should be possible to combine the conservation of designed landscape parks with wildlife conservation, but the process of managing the parkland is vitally important. Attention needs to be paid to the age structure of trees, the total numbers of trees, and their patterns of density. It is continuity over time that makes Brown’s parklands so invaluable for saproxylics and should provide a framework to guide conservation action.
The areas surrounding the landscape parks have often been impoverished through ‘improvement’ and modern technology, and it is these impacts of modern technology that have impacted on species richness rather than landscaping. There could therefore be a case for fully restoring Brown landscapes, for example by abandoning the use of modern agrichemicals, controlling spray drift and groundwater pollution, banning motor vehicles from parks, keeping old breeds of livestock at lower stocking levels, and using traditional methods of tree management.
Why are these principles rarely part of parkland restoration and maintenance plans today?