Early Postfire Vegetation Dynamics of Shrub-steppe Communities (On the example of Burtinskaya Shrub-steppe of Orenburg Nature Reserve)

Abstract

The intensification of fire regime in the shrub-steppe determined the need for research aimed at identifying the regularities of the effect exerted by wildfires on shrub-steppe ecosystems and one of their most dynamic components referred to as plant cover. A present study was carried out on the territory of Burtinskaya Steppe of the Orenburg Reserve and in its protected area in 2015–2016, following the fire that occurred in August 2014. It was found out that in the first year following a fire event, the total plant cover of steppe ecosystems affected by a wildfire is almost halved. The plant cover dominated by bunchgrasses, especially of the genus Stipa, significantly decreases, and the abundance and diversity of ephemeroids increase. The floristic alteration manifesting itself in the form of an invasive role of certain species (most often ephemeroids and biennials) during one vegetative stage is endemic to the areas exposed to overgrazing in the past. The outburning of plant cover can bring about a change in dominant and codominant plant species within a shrub-steppe assemblage.

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