Coppicing deciduous woodland promotes diversity of spider species

Coppicing is a traditional woodland management activity that involves cutting mature trees at the base and allowing them to regrow, with multiple trunks, from the stump. The practice dates back to the Stone Age and was widely used across Europe from the Middle Ages until the 18^th century. Since then, the practice has been declining, and, while 14% of European forests are still officially designated for coppicing, there is evidence to suggest that in many countries this is rarely carried out¹.

Although originally practised to produce convenient poles and logs, coppicing has since been shown to have beneficial effects for woodland biodiversity. The gaps that coppicing creates in the tree canopy allow sunlight to reach the forest floor, stimulating the growth of different plant species and creating a wider variety of habitats within the woodland ecosystem.

This study aimed to evaluate the impact of coppicing on invertebrate diversity at successive stages following the initial cut. Focusing on spiders – an ecologically significant group typically comprised of dominant predators within invertebrate communities – the researchers aimed to fill a knowledge gap concerning the impact of successional development on the biodiversity of these creatures.

The oak woodlands of Podyji National Park, Czechia, were coppiced for centuries until the practice was abandoned in the 1950s. In 2015, the park management began a coppicing programme in two separate zones. This study examined locations in both zones that had been coppiced one, two, five and six years previously, and areas that had not recently been coppiced. The researchers sampled spiders by setting traps in the ground which were emptied monthly from April to October 2021.

The researchers identified 9 919 individual spiders from 143 different species. They reported that the ‘species richness’ – the total number of species collected at each location – varied according to the time since coppicing. This was most notable after five and six years when, in both cases, species richness was significantly higher at the coppice sites than in the unmanaged woodland; whereas homogenous assemblages of spiders inhabited the unmanaged stands, at the sites where coppicing had led to an opening of the canopy, researchers recorded a significant increase in spider biodiversity.

The researchers identified different spider communities in the early regrowth (one- or two-year), later regrowth (five- or six-year) and undisturbed patches, corresponding to the different stages of vegetation development. In the early stage after opening the forest canopy, predominantly light-demanding species were present on the relatively clear forest floor. In the later stage these were still present, but a wider range of species now occupied the increasingly complex vegetation structure. In the undisturbed patches, the community consisted of a more homogenous set of highly shade-tolerant and humidity-demanding species, with significantly lower body sizes than those found in the later regrowth areas.

The researchers highlight that the biodiversity benefits of coppicing are not immediate, in this case, but become more notable after several years of successional development. They acknowledge that the study is limited by the sampling method, which only collected spiders that are active on the ground, but argue that this is unlikely to affect the overall findings.

The researchers suggest that these results support the case for reinstating coppicing as another potential complementary management strategy for increasing the biodiversity of deciduous woodlands in Europe, noting the effectiveness of this practice in creating complex habitats that provide ecological niches for a wide range of species.

Footnotes:

1. The study highlights that since the nineteenth century, fossil fuels and new construction materials replaced coppice products, and abandoned ancient coppices were gradually converted into high forests and plantations. During this process, the formerly coppiced woodlands have generally become cooler, moister and greater in nutrients than in previous centuries. The loss of the complementarity between open- and closed-canopy forest has resulted in an overall loss of biodiversity and a decline of currently threatened species that depend on open-canopy forests.

Source:

Hamřík, T., Košulič, O., Gallé, R., Gallé-Szpisjak, N., and Hédl, R. (2023) Opening the canopy to restore spider biodiversity in protected oakwoods. Forest Ecology and Management, 54: 121064.

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“Science for Environment Policy”: European Commission DG Environment News Alert Service, edited by the Science Communication Unit, The University of the West of England, Bristol.

Notes on content:

The contents and views included in Science for Environment Policy are based on independent, peer reviewed research and do not necessarily reflect the position of the European Commission. Please note that this article is a summary of only one study. Other studies may come to other conclusions.