Refine
Document Type
- Article (2)
Language
- English (2)
Has Fulltext
- no (2)
Is part of the Bibliography
- yes (2)
Keywords
- Secondary succession (2) (remove)
Institute
- Fakultät AuL (2) (remove)
The aim of this study is to assess the development of plant species diversity and species composition
over a seven-year period in two calcareous grasslands abandoned for nearly 20 years and to find out
which factors influence vegetation dynamics. In the Abava River valley, Latvia, different calcareous
grasslands were studied, one on the south-west facing slope and another on the north-east facing slope.
Vegetation analyses on permanent plots showed that dry calcareous grasslands can be resistant to deterioration for a long period of time – succession was slower than reported in many cases for Central and
Western Europe. None of the studied communities showed a decrease neither in total species number
recorded per community nor in average species richness per plot. Vascular plant species richness even
increased by 3–4 species per 1-m² plot in the grassland on the south-west facing slope. An unexpected
result of the research was that Calamagrostis epigeios did not expand in this grassland. This fact can be
explained by the influence of disturbances (drought, tree cutting) and local differences in soil parameters
and topography. In parts of the north-east exposed grassland, with deeper soils and better water availability, species diversity (Shannon index) decreased significantly in areas overgrown by Aegopodium
podagraria.
Following the collapse of the Soviet Union in 1991 around 45 million hectares
of arable land became abandoned across Russia. Our study focused on the recovery
potential and conservation value of grassland vegetation on ex-arable land in the Tyumen
region of the Western Siberian grain belt. We compared ex-arable grasslands of different
successional stages with ancient grasslands as reference for the final stage of succession
along a climatic gradient from the pre-taiga to the forest steppe zone. Plant community
composition and species richness of ex-arable land clearly developed towards reference
sites over time, but even after 24 years of abandonment, the grassland vegetation had not
totally recovered. The c-diversity of vascular plants was slightly higher on ex-arable land
than in ancient grasslands but the mean a-diversity was still moderately lower. A significant proportion of the vegetation of ex-arable land still consisted of ruderal and mesic
grassland species and the number and cover of meadow-steppe species was significantly
lower than in ancient grasslands. Grazing and time since abandonment positively affected
the reestablishment of target grassland species, whereas it was negatively affected by the
cover of grasses. In contrast to ex-arable land, the conservation value of arable land is only
modest. Therefore, future intensification of land use is most likely less harmful if directed
to existing arable land. Re-cultivation of ex-arable land and grassland improvement operations such as seeding of competitive grass species are major threats for the biodiversity of secondary grasslands on ex-arable land in the forest steppe zone of Western Siberia.