The role of semi-open habitats as dispersal corridors for plant species of woodlands and open habitats

Questions European pasture landscapes have been shaped by grazing and alternate husbandry. They are structurally characterised by mosaics of open habitat patches, individual trees and groups of trees or shrubs. We investigated whether these semi-open habitats may act as stepping stones and thus as dispersal corridors for both plants from woodlands and open habitats to mitigate habitat fragmentation effects. We (a) contrasted the plant communities in semi-open habitats with those of woodlands and open habitats, and (b) explored which life-history traits or environmental requirements are associated with the presence or absence of species in semi-open habitats. Location Swabian Jura, South Germany; Lueneburg Heath, North Germany. Methods We selected four study sites in two contrasting landscapes and conducted vegetation surveys and analysed canopy closure and soil chemical properties in four different habitat types: woodlands, semi-open habitats with high and low canopy closure and open habitats. We tested whether habitat type affected species composition, identified habitat-specific indicator species and compared Ellenberg indicator values for light and moisture and species' dispersal and establishment traits across these habitat types. Results Plant communities of woodlands were significantly different from those of all other habitat types, whereas open habitats showed some similarities to semi-open habitats. On average, 73% of open habitat and 39% of woodland species were present in semi-open habitats. Habitat requirements as well as dispersal and establishment traits of woodland species were often more specialised and differed from those of species of the other habitat types, making them less capable to disperse into semi-open habitats. Conclusions Semi-open corridors have the potential to connect patches of open habitats and to a lesser extent also of woodlands without creating new barriers for either habitat type. Thus, semi-open corridors may counteract habitat fragmentation effects and are a promising tool for biodiversity conservation, particularly in fragmented pasture landscapes.

Automated summary

The study suggests that semi-open habitats in European pasture landscapes may serve as dispersal corridors for plants, connecting woodlands and open habitats to mitigate habitat fragmentation. Woodland species have more specialized habitat requirements and dispersal traits, making them less capable of dispersing into semi-open habitats.