Germination response of woody species to laboratory-simulated fire severity and airborne nitrogen deposition: a post-fire recovery strategy perspective

Abstract

12:52 severity) for 5 min] and N fertilisation (without N and with addition of 4.17 g Nm of solid granules of ammonium nitrate, equivalent to three times the current estimate of airborne N deposition in the study area) under laboratory conditions. We found that N fertilisation had a significant, negative effect on the rate of seed germination of the three species under study. Additionally, we detected no differences in P. pinaster germination among thermal treatments; while both P. tridentatum and H. lasianthum had significantly higher germination rates when submitted to high fire-severity conditions. Moreover, the average time of seed germination increased with N fertilisation for P. pinaster but increased after the thermal treatments for H. lasianthum. These results suggest that increased N availability under intense wildfire regimes may hinder post-fire seed germination, regardless of the species' regeneration strategy, in fire-prone pine forests.

Effect of fire on viability and germination behaviour of Cistus ladanifer and Cistus salvifolius seeds

“…For this purpose, seeds of both species were subjected to different heat-shock treatments simulating natural fire conditions (50-175°C for 1 and 5 min). To elucidate the ecological significance of the effects of fire, viability and different traits informative about the dynamics of the germination process, such as final germination percentage (FGP), first day of germination (FDG), last day of germination (LDG), time spread of germination (TSG) and coefficient of and Southwestern Australia, and Central Chile (Keeley 2012), ecosystems in the Mediterranean Basin are prone to fires (Daibes et al 2019;Valbuena et al 2019). They constitute one of the most predictable disturbances faced by plants (Di Castri et al 1981).…”

“…Rural exodus and the establishment of forest and shrubland on abandoned land have contributed to an increase in fire incidence in Southern Europe (Mouillot and Field 2005). Moreover, an increase in fire frequency is expected in the future as a result of climate change (Valbuena et al 2019).…”

“…Fire cues and changes provoked in the environment can influence plant vital processes such as flowering, fruiting and seed germination (Zirondi et al 2019). In consequence, fire produces alterations in plant competitive interactions (Valbuena et al 2019), thus affecting the structure and dynamics of plant populations and communities (Whelan 1995;Bond and van Wilgen 1996).…”

“…Apart from being an important ecological factor, fire may also act as a selective pressure in fire-prone habitats (Valbuena et al 2019). Therefore, in Mediterranean ecosystems, numerous species have acquired fire-related traits and mechanisms, which can confer an adaptive advantage in repeatedly burnt ecosystems (Saracino et al 2017;Valbuena et al 2019;Zirondi et al 2019). Different strategies have been observed in plants adapted to fire regimes related to both vegetative and reproductive features.…”

“…Different strategies have been observed in plants adapted to fire regimes related to both vegetative and reproductive features. According to Valbuena et al (2019), in these ecosystems, regeneration of plant species after fire largely depends on both their capacity to withstand high temperatures during fire and their strategy for persisting after fire. Traits that contribute to bear the fire include protection of meristems, usually located at the ground level (e.g.…”