We applied a series of intra-and interspecific in situ cross-pollination experiments under greenhouse conditions to evaluate the breeding systems in four Fosterella species (Pitcairnioideae s.str.; Bromeliaceae). Viable hybrids were produced between each pair of the investigated species, suggesting that reproduction barriers may be low also under natural conditions. Seed germination rates proved to be high in each crossing treatment, indicating a high viability of the artificial hybrids. Large numbers of seeds were produced after both closed and open pollination treatments, suggesting that autogamy may be a major reproductive strategy in the genus. Our results support the concept that self-compatibility is an appropriate way to avoid natural hybridization in Bromeliaceae and could assist in maintaining species integrity in the presence of pollen flow. Paternity was verified in all crosses by genotyping parents and offspring with a set of polymorphic nuclear microsatellite markers. To study the mode of chloroplast inheritance, we developed a novel set of 24 chloroplast microsatellite markers using 454 pyrosequencing technology, and applied four of these markers for genotyping parents and offspring from all crosses. Our results clearly demonstrated a maternal inheritance of plastids.

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Climate change challenges important native timber species in Central Europe. The introduction of non-native tree species originating from warmer climates is one option to make Central European forests compatible to global warming. This, however, requires an assessment of the species’ growth requirements, and of its impact on biodiversity in its native ranges. Silver lime (Tilia tomentosa), a moderately drought-tolerant, thermophilous tree species of South-eastern Europe is considered suitable for the future. Along three elevational transects in western Romania, we assessed the impact of changing climate and local site conditions on the abundance of this tree species and contrasted plant species diversity and composition of lime-dominated forests with mesophytic oak and beech forests. Local site conditions and disturbance histories shaped the distribution pattern of silver lime. When dominant, it reduced plant species diversity within stands due to its dense canopy. For shade-tolerant, mesophytic species, though, lime forests provided an additional habitat and extended their range into warmer environments. Thus, silver lime may have the potential as an admixed tree species forming a transitory meso-thermophilous habitat in the future. At the same time, silver lime may be limited under increasing drought frequency.