Coppice abandonment and its implications for species diversity in forest vegetation

Abstract

Coppicing, once a common type of management in European broadleaved forests, was abandoned in many places after WWII. This form of management provided a variety of structural and microclimatic conditions for tree and understorey vegetation. After the abandonment of this intensive management, succession towards mature close forests ensued, and suitable habitats for species ecologically connected to coppicing were reduced. In our study, we chose a region in central Europe where coppicing was the dominant type of forest management until the first half of the 20^th century but was abandoned after WWII. We investigated long-term changes in both woody and herbaceous species composition in the Lower Morava UNESCO Biosphere Reserve using historical sources and vegetation plot resurveys from the 17^th to the 21^st century. The impact of coppice abandonment on vegetation composition and on the conservation value of forests was evaluated. Dominant tree species appeared to be very stable throughout the past four centuries, but changes occurred in their proportions. A shift from species rich oak-hornbeam woodland towards species poorer communities with increasing proportions of lime, ash and maple was observed after the abandonment of coppicing. The observed tendencies partly differed according to site and data source. The conservation value of forests was measured as the occurrence of red-list species, which were considerably reduced after coppice abandonment. To stop the process of biodiversity loss and support the goals of nature conservation, the re-establishment of coppice management is proposed.

Keywords: conservation; forest management; forest species composition; history; resurvey of semi-permanent plots; vegetation diversity.

Figure 1

Map of the study area with all type of protection marked (PLA = Protected Landscape Area, BR = Biosphere Reserve).

Figure 2

Environmental gradient of the Dĕvín Hill. NW-SE section shows four main vegetation types including three ecologically and floristically distinct forest types, confined to specific environmental conditions defined by topography and soils.

Figure 3

Changes in underwood tree abundances in Dĕvín (a) and Milovice (b) Woods based on archival forestry data. Black bars represent abundance in the 1950s, white ones in the 1970s and grey ones in 2010. For Milovice Wood, only 1970-2010 data were available.

Figure 4

Environmental gradient of the Dĕvín Hill from NW to SE reflected in shifts in tree abundances during the last sixty years.

Figure 5

Changes in the presence of tree species based on resurveyed vegetation plots in Dĕvín (a) and Milovice (b) Woods. Tree and shrub layers were merged. Black bars represent frequency (% of plots with a species) in the 1950s and grey ones in the 2000s. Black pine is missing in the plots from Milovice Wood. Significance codes are 0.001 '***', 0.01 '**', 0.05 '*'.

Figure 6

Changes in average Importance Value of tree species based on resurveyed vegetation plots in Dĕvín (a) and Milovice (b) Woods. Graph design is same as in Fig. 4. Significance codes are 0.001 '***', 0.01 '**', 0.05 '*'.

Figure 7

Change in species richness in herbaceous layer of two studied forests. Plot-wise difference between the number of species in new and old sample is calculated as % of the number of species in the old sample. Boxes show median and interquartile range, vertical bars are non-outlier range and circles outlier values. Three values exceeding the upper range of displayed change are not shown. Changes in both sites are statistically significant at p<0.001.

Figure 8

Estimation of species richness by rarefaction curves for Dĕvín (a) and Milovice (b) Woods. Black symbols and lines are for the 1950s vegetation surveys, grey colour is used for the 2000s surveys. Mean species richness is by rows of circles, 95% confidence intervals are by lines accompanying means.

Figure 9

Changes in endangered herb layer species for Dĕvín (a) and Milovice (b) Woods. Relative occurence (percentage) of the Red List species for the Czech Republic from the occurence of all species in the datasets. Differences between the old and new samples were statistically insignificant (at p<0.05).