At the weekend I travelled over to Oxford to go to the annual BENHS (British Entomological and Natural History Society) AGM. It was, in a few words, pretty great. A day full of lectures about various British insects, including art, history and a tour around the stacks of the Oxford Natural History Museum afterwards to see some of the collections.
One of the best days out I’ve had in ages- and you don’t actually have to be a member to attend the day either, which is great. The next couple of blog posts are going to be about what I learnt that are also pretty relevant to what we do over here at Juniper Hall.
Woodland ecosystems and saproxylic species
Saproxylic species are organisms that live in deadwood. The BENHS talk was focussed on woodlands, so I am going to as well- most of the research on saproxylic species focuses on woodlands. Saproxylic species make up 7% of all British fauna– there are over 800 beetles, 730 flies, 300 hymenoptera (bees, ants and wasps), and 50 moth species present within deadwood. Unfortunately many of these species are threatened by the need for “tidy woodlands“- the removal of deadwood. Over-management of parks and woodland gardens has a lot of fallen deadwood removed, to try and keep an area tidy. Standing deadwood and timber branches are also regularly removed, as it’s thought to be dangerous or a potential haven for diseases and pests.
Types of deadwood (Source: TVC)
At European scale, 11% of saproxylic beetles are threatened. It might be that part of the problem is due to woodland management, where modern harvesting practice does not allow trees to fully mature, cropping them before they can naturally produce deadwood. In areas that have been previously coppiced or pollarded, deadwood invertebrates are likely to persist in tree hollows, although the loss of this traditional woodland management causes saproxylic invertebrate numbers to decrease.
Please help me! (Source: Greg Humphries)
So what’s better? To manage a woodland traditionally, using coppicing and pollarding, or to leave woodlands completely alone and prevent “tidying” of woodland, allowing a deadwood environment to emerge on the ground? Certainly it seems that either method is better than modern techniques of harvesting an area for trees, as this causes the total removal of material even before deadwood can form. It has been noticed that coppiced areas can produce special microclimates for deadwood fauna, however if an area is too-well managed, coppice reverts to being of little importance for deadwood conservation.
To coppice, or not to coppice? (Image credit: geograph.org.uk)
Perhaps it’s too difficult to draw a conclusion on the best way to manage woodland for deadwood invertebrates when there’s little currently being researched on a large scale- more important, it seems, is to just try and create deadwood habitats to start off with, and worry about woodland management when our saproxylites are a little bit more stable in the future.
A happy home for many invertebrates (Source: Buglife.com)