Erdős L, Cs Tölgyesi, L Körmöczi et al: The importance of forest patches in supporting steppe-species... (2015)

Erdős L., Tölgyesi Cs., Körmöczi L., Bátori Z.
The importance of forest patches in supporting steppe-species: a case study from the Carpathian Basin
Polish Journal of Ecology 63: pp. 213-222.
Angol nyelvű összefoglaló: 

Moderating effects of trees on the environment in their immediate
proximity are considered an important force in structuring plant
communities, especially in harsh environments. In the semi-arid regions
of the middle Carpathian Basin, such facilitative influences are expected
to become crucial for the survival of several plant species, given the
current warming and drying tendencies. We used 20 × 20 m plots to
analyze whether grassland species adapted to mesic conditions penetrate
forest patches, where they are able to survive. Using transects and the
moving split window analysis, we also investigated how far the positive
effects of the forest patches extend into grasslands, and whether this
enables the existence of a steppe community that cannot tolerate extreme
dry conditions and unfavorable soils. We found that beside forest-related
species, forest patches hosted large numbers of grassland-related species.
Among them, plants of closed steppe grasslands were the most numerous,
which usually cannot tolerate the harsh conditions of open sandy
grasslands, and are often confined to areas with better water and soil
conditions. Our results showed that there is a 5−8 m wide closed steppe
zone around the forest patches. Some species that are not able to survive
in open xeric sandy grasslands are restricted to this zone. Unfortunately,
while considerable attention is paid to the research, protection and
restoration of sandy grasslands, forest patches are usually neglected. Our
results emphasize that the establishment of individual trees and groups of
trees should be actively promoted, because they have considerable nature
conservation benefits by supporting closed steppe species.