Abstract

Water level fluctuation in Lake Naivasha has resulted in loss of papyrus cover. Land exposed after receding of the lake has been put under grazing and cultivation. A 3 months study was conducted to establish whether the varying number in years of land exposure (chronosequence) and differences in land use had affected the ability of papyrus seeds to germinate and thrive in these soils. Soil samples were collected at areas of different chronosequence and land use. They were put under water saturation conditions; germination and biomass accumulation rates of papyrus were observed. ANOVA was used to test for any significant differences in the measured variables amongst sites. Data not meeting normality assumptions was analyzed using Kruskal-Wallis test. With treatment one (over seeded sterilized soils), germination results revealed a significant influence of predictor variables; land use (χ² = 28.7; df = 2; p<0.001) and duration (χ² = 94.1; df = 3; p<0.001). Germination results for treatment two (seed bank soils), also revealed a significant impact of duration (χ² = 94; df = 3; p<0.001) and land use (χ² = 34.7; df = 2; p<0.001). This study provides vital information on areas where viable diaspores are still present. It also helps in identifying areas where viable papyrus seeds no longer exist, thus necessitating human intervention by way of seed re-introduction. With over seeding, papyrus restoration was found to be possible even in areas with no viable diaspores. Further research is necessary to establish if there are viable vegetative parts left in these soils as their regeneration could speed up papyrus restoration efforts.

Keywords:

Chronosequence, germination rate, papyrus, seed bank, viable diaspores,

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