In:
Applied Vegetation Science, Wiley, Vol. 20, No. 1 ( 2017-01), p. 74-83
Abstract:
How do land‐use legacies, tree encroachment and distance to the edge interact to determine species richness patterns in the ground vegetation of an unmanaged heathland? What are the direct and indirect effects of these factors? Do different functional groups respond differently to these factors? Location Nørholm heathland, southwest Denmark. Methods We recorded the overstorey and ground vegetation along with environmental variables in 129 plots on a 350 ha heathland where management ceased more than 100 yrs ago. We used structural equation models ( SEM ) to examine the relationship between species richness of functional groups (herbs, dwarf shrubs and tree seedlings) and ground vegetation cover, overstorey development, distance to the edge and nutrient availability. Results The relative importance of the driving factors differed between functional groups. Herb richness increased with increasing nutrient availability from previous land use and decreased with overstorey development. Dwarf shrub richness responded negatively to overstorey development and herb cover. In contrast, species richness of tree seedlings responded strongly and positively to overstorey development but not to environmental variables or ground vegetation. In general, the effect of nutrient availability and distance to the edge were of similar magnitude and were largely mediated by the overstorey and ground vegetation. Conclusions Land‐use legacies and tree encroachment can have differential effects on the species richness of different functional groups. Typical heathland dwarf shrubs were able to withstand moderate levels of increased nutrient availability and tree colonization. However, the combination of these factors poses a serious threat, as dwarf shrub richness decreased due to an increase in the cover of herbaceous species and light limitation. The absence of management did not lead to a rapid loss of typical heathland species.
Type of Medium:
Online Resource
ISSN:
1402-2001
,
1654-109X
DOI:
10.1111/avsc.2017.20.issue-1
Language:
English
Publisher:
Wiley
Publication Date:
2017
detail.hit.zdb_id:
2053083-3
SSG:
12
SSG:
23
