The effects of seed sowing to recreate species-rich semi-natural grasslands on former arable land in rural southeast Sweden

Background

Many plants of semi-natural grasslands in northern Europe are threatened because of a decline in traditional management, e.g. livestock grazing and hay-making. In this Swedish study, seed sowing was examined to assess to what extent seeding of former arable fields now under grass, increases species richness and generates a species composition typical of semi-natural grasslands in the region.

Action

Study area: The study was performed in southeastern Sweden (58°50’ N, 17°24’E). Four types of grassland with different current and past management were chosen in which to sow a selection of typical grassland species:

1) former arable field, grassland grazed for 30 years (2.5 ha);
2) former arable field, grassland grazed for 10 years (1.8 ha);
3) grazed semi-natural grassland (continuously grazed since 17th century) (2.6 ha);
4) abandoned semi-natural grassland (previously grazed, abandoned 40 years ago) (1.4 ha).

None of the grasslands had been artificially fertilized and soil conditions were similar.

Study species: Twelve native species of in semi-natural grasslands in the region were sown:

Species favoured by grazing (target species): harebell Campanula rotundifolia, eyebright Euphrasia stricta, ox-eye daisy Leucanthemum vulgare, hoary plantain Plantago media, cowslip Primula veris, yellow rattle Rhinanthus minor.

Generalists favoured by no grazing: cow parsley Anthriscus sylvestris, brown knapweed Centaurea jacea, meadowsweet Filipendula ulmaria, field forget-me-knot Myostis arvensis, dandelion Taraxacum vulgare, red clover Trifolium pratense.

Sowing and seedling emergence: Seed was collected locally in autumn 2000 and sown within 2 weeks. Each species was sown in separate 10 cm x 10 cm plots (10 replicates) at each grassland at four densities: 10, 21, 46, and 100 seeds. Ten plots were left unsown as controls. Seedling emergence was recorded in June 2001 in randomly placed 1 m² quadrats.

Consequences

Target and generalist species emerged in all the grasslands. The average proportion of sown seeds emerging differed among species (range: 1.2-12.6%), but total seedling emergence was similar for target and generalist species and was best in the grazed grasslands. The highest proportion of seeds germinated at an intermediate sowing density (20-50 seeds/dm²).

Target species recruited well in the former arable fields. The generalists also recruited well at grazed sites. All sown species performed poorly in the abandoned grassland. The two grasslands with the longest grazing history (continuously grazed grassland and former arable grazed for 30 years) were positively associated with emergence of target species.

Whilst seeding enhanced species richness in the grazed grasslands, it is not known whether these species will establish in the long term.


Note: If using or referring to this published study, please read and quote the original paper, this can be viewed at: http://www.springerlink.com/content/x4mv082w73p11206/fulltext.pdf