Forest fires have long-term effects on the composition of vascular plants and bryophytes in Scots pine forests of hemiboreal Estonia

Abstract

Since fire frequency is expected to increase globally due to climate change, it is important to understand its effects on forest ecosystems. We studied the long-term patterns in species diversity, cover and composition of vascular plants and bryophytes after forest fire and the site-related factors behind them. Research was carried out in northwestern Estonia, using a chronosequence of Scots pine ( L.) stands, located on nutrient poor sandy soils, where fires had occurred 12, 23, 38, 69, 80 and 183 years ago. In every stand three 100 m vegetation plots were established to collect floristic and environmental information. The effects on floristic characteristics of time since fire, light, and soil variables were evaluated with linear mixed models, followed by backward variable selection. Compositional variation was analysed with non-metric multidimensional scaling, Multi-response Permutation Procedures, and Indicator Species Analysis. Altogether, 31 vascular plant and 39 bryophyte species were found in vegetation plots. The cover of the vascular plant and bryophyte layers increased with a longer time since fire. Soil and light variables impacted the richness of several vascular plant and bryophyte groups, whereas only the richness of liverworts and dwarf-shrubs correlated with time since fire. Considerable compositional differences were observed in vascular plant and bryophyte assemblages between recently vs. long-time ago burned stands. To conclude, time since fire significantly impacted compositional patterns of vascular plants and bryophytes in pine forests on nutrient poor soils, although time-related trends in species richness were less evident.Pinus sylvestris2

Effects of Fire on Pyrodiversity of Terricolous Non-Tracheophytes Photoautotrophs in a Páramo of Southern Ecuador

“…This is possibly related to the recovery time for low-severity burns. Supporting our results, previous studies have indicated the effects of fire on the richness, diversity, and composition of bryophytes and lichens in temperate and boreal zones [26,[60][61][62][63][64][65] The richness of lichen and bryophyte species is higher in the control because species belonging to the bryophyte group (e.g., Breutelia, Rhacocarpus, and Syzygiella) were exclusive in the control plots. Supporting our results, previous studies have documented that the richness of cryptogams decreases in soils degraded by fire [43,44,66].…”

“…In this context, Greene et al [43] and Zabala et al [66] showed that the effect of fire on the diversity of lichens and bryophytes can be temporary; therefore, their diversity can recover with the passage of time monitoring [43,44,66]. Similarly, Orumaa et al [63] and Pharo et al [71] showed that the post-fire effect has positive consequences on the diversity and richness of terricolous cryptogams due to the increase in nutritional contents such as N, K, Ca, Mg, Fe, and Mn. Finally, Wienskoski and Santos [27] point out that the richness and diversity of terricolous cryptogams (e.g., bryophytes) are limited by the time after the fire, that is, the diversity is greater when the time after the fire increases.…”

“…These changes in diversity could be limited due to some soil factors (e.g., carbon availability) because fire modifies the physical and chemical characteristics of the soil [67][68][69]. For example, several studies have documented that fire alters nutrient availability (e.g., increase in K, Ca, Mg, and P levels and decrease in Zn, Cu, Fe, and Mn levels), and this implies changes in the diversity of terricolous bryophytes and lichens [63,70].…”

“…Similarly, Hylander et al [62] showed that variation in bryophyte species composition was strongly related to time since fire. Likewise, Orumaa et al [63] mentioned that the time since the last forest fire affected the composition patterns of vascular plants and terricolous cryptogams. In addition, the most representative lichen families reported in this study were Cladoniaceae and Baeomycetaceae, and as for bryophytes, Dicranaceae, Jungermanniaceae, Bartramiaceae, Rhacocarpaceae, and Pallaviciniaceae.…”