Long-term effects of burning Festuca and Stipa-Agropyron grasslands
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Published source details
Pylypec B. & Romo J.T. (2003) Long-term effects of burning Festuca and Stipa-Agropyron grasslands. Journal of Range Management, 56, 640-645.
Published source details Pylypec B. & Romo J.T. (2003) Long-term effects of burning Festuca and Stipa-Agropyron grasslands. Journal of Range Management, 56, 640-645.
Summary
Kernen Prairie in Saskatchewan (52°10'N, 106°33'W), central Canada, is a 130 ha grassland comprising native Festuca-dominated communities (near the southern extent of their distribution) and Stipa-Agropyron communities (typical of more southern grasslands). It has been relatively undisturbed since the 1930s except for mowing of some sections until 1976, and since 1986 some parts have been subject to prescribed burning and vegetation responses described. Following from this, the effects of early spring burning over 11 years on standing crop and litter were examined in both grassland types.
From 1991 to 1997, representative areas (4-16 ha) of Festuca (moister, rough fescue Festuca hallii dominated grassland) and Stipa-Agropyron communities (more xeric sites dominated by western porcupine grass Stipa curtiseta and northern wheatgrass Agropyron dasystachyum) were burned in the first half of April each year. Each was paired with a control (located within 20 m; no fire recorded for 80 years).
Aboveground plant biomass was sampled from 1991 to 2001 (except 2000), in late July to mid-August (time of peak standing crop). Vegetation in four (50 x 50 cm) quadrats along a 20 m transect in each burn and control area was clipped at ground level and sorted into graminoids, forbs, and shrubs. Fallen litter was collected by hand. Samples were oven-dried and weighed. A graminoid subsample (comprising most of sample bulk; about 95% in Festuca- and 99% in Stipa-Agropyron-dominated communities) was separated into green biomass, current year dead biomass and dead biomass from previous years and weighed.
‘Current year standing crop’ was the total green biomass plus current year dead biomass. ‘Litter’ comprised fallen, detached and standing dead biomass from previous years. ‘Total standing crop’ was litter plus current year standing crop.
In Festuca communities a trend of less current year standing crop was observed after burning (reduced in the first and third years) , but there was no statistically significant difference compared to the control in the second year and after the third.Burning Stipa-Agropyron-communities likewise tended to reduce current year standing crop, but differences were not significant compared to controls.
Higher precipitation enhanced current year standing crop after burning in both grassland communities. In Festuca grassland, litter and current year standing crop were correlated (where litter biomass was higher, production was lower); this was not evident for Stipa-Agropyron communities. In both grassland communities, total standing crop increased until about the eighth year after burning while litter peaked around 11 years, indicating that this length of time is required for litter to reach levels comparable to unburned sites.
At the time of burning, prairie crocus Anemone (Pulsatilla) patens was in early stages of blooming; whether it was detrimentally affected is not reported.
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