Physical and chemical effects of litter on plant establishment in semi-natural grasslands |
| |
Authors: | Knut Anders Hovstad Mikael Ohlson |
| |
Institution: | 1.Department of Ecology and Natural Resource Management,Norwegian University of Life Sciences,?s,Norway;2.Norwegian Institute of Agricultural and Environmental Research,Kvithamar, Stj?rdal,Norway |
| |
Abstract: | A field experiment was conducted in a semi-natural grassland to study the interspecific variation in the effect of litter
on seedling emergence and establishment and separate physical from chemical effects. Seeds of seven forb species were sown
in plots subjected to either litter amendment (0, 400 or 900 g m−2) or water extracts of litter (corresponding to 400 and 900 g litter m−2). In addition, an extract was treated with activated carbon to estimate the possible effects of secondary chemical compounds.
The response to plant litter differed amongst species: negative, neutral and positive responses were observed. Anthriscus sylvestris was the only species with a strong positive response to litter. We found no consistent relation between seed size and response
to plant litter. Physical effects of litter were generally stronger than chemical effects. However, water extract of litter
inhibited emergence in three species. Activated carbon removed the negative effect of the litter extract, which suggests that
the effect was caused by an inhibitory chemical compound rather than by increased competition in response to nutrients added
via the extract. The balance between facilitative and inhibitory effects of litter depended on species identity and litter
quantity. Facilitative effects dominated at low and intermediate quantities of litter, and inhibitory effects at high litter
quantities. One species, Campanula rotundifolia, showed a switch from positive to negative responses with increasing quantities of litter. However, we found no general threshold
for litter quantity valid across species. |
| |
Keywords: | Activated carbon Facilitation Germination Plant litter Seedling establishment Semi-natural grassland |
本文献已被 SpringerLink 等数据库收录! |
|