Impact of forest fire on soil seed bank composition in Himalayan Chir pine forest

Aims To explain how plant community copes with a recurring anthropogenic forest fire in Himalayan Chir pine forest,it is important to understand their postfire regeneration strategies.The primary aim of the study was to know:(i)how fire impact soil seed bank composition and(ii)how much soil seed bank composition differs with standing vegetation after the forest fire.Methods Soil samples were collected from burned and adjoining unburned sites in blocks using three layers down to 9 cm depth immediately after a forest fire and incubated in the net-house for seedling emergence.Same sites were revisited during late monsoon/early autumn season to know the species composition of standing vegetation recovered after a forest fire.Important Findings Soil contained viable seeds of>70 species.The average seed bank density was 8417 and 14217 seeds/m^(2) in the burned and unburned site,respectively.In both sites,it decreased with increasing soil depth.Overall fire had no significant impact on seed density;however,taking individual layers into consideration,fire had a significant impact on seed density only in the uppermost soil layer.The species richness of soil seed bank and standing vegetation was 73 and 100,respectively(with 35 shared species),resulting in a similarity of about 40%.In contrast,>80%species in soil seed bank was found similar between burned and unburned sites.Further,there were no significant differences in species richness of standing vegetation in burned(87 spp.)and unburned(78 spp.)sites.Our results showed that fire had an insignificant impact on soil seed bank composition and restoration potential of a plant species from seeds.The understory herb and shrub plant community’s ability to form a fire-resistant viable soil seed bank and capable to recover in the postfire rainy season,explains how they reduce the risk of recurring fire damage in maintaining their population.

Influence of aerial seed banks on germination response in three desert plant species

Aims To determine if the germination response of desert plant species to a period of aerial storage in field conditions(i.e.mature seeds that remain attached to the parent plant)is comparable to seeds harvested at maturity and stored in ambient laboratory conditions,to better understand the role of aerial seed bank in the germina-tion ecology of desert plants,using one annual and two perennial species.Methods Seeds of three desert plants(Anastatica hierochuntica,Blepharis ciliaris and Scrophularia deserti)that matured in June 2014,were collected from wild plants in June and November 2014,and ger-minated under two photoperiods(0,12 hours light)and three ther-moperiods(night/day temperatures of 15/25,20/30 and 25/35°c).Important Findings Seeds of B.ciliaris and S.deserti had significantly higher germination percentages when harvested and stored for five months,compared to being stored in the aerial seed bank.Germination percentages of these two species increased with decreasing temperature and in the presence of light.These results indicate that these species use a com-bination of aerial and soil seed banks to maintain a percentage of viable seeds through favourable germination periods.Germination percentages of A.hierochuntica were high under all tested circum-stances,indicating that this species relies mainly on the aerial seed bank to maintain a percentage of viable seeds through favourable germination periods.This study shows that the population survival strategies of an aerial seed bank are species-specific.These results have practical implications for conservation and habitat restoration for these species,and also for their propagation since early collec-tion of mature fruits and ex situ storage will result in greater germi-nation percentages of some species.