To burn or not to burn? Effect of management strategy on North American prairie vegetation for public urban areas in Germany.

Anil Shrestha,Anja Schmithals,Norbert Kühn

doi:10.1371/journal.pone.0108588

Anil Shrestha, Anja Schmithals + Show 1 more

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https://doi.org/10.1371/journal.pone.0108588

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Abstract

North American prairie vegetation has been a role model for designing highly attractive plantings for German urban green spaces for the past decade. In combination with gravel mulch top layers on planting sites and non-selective maintenance techniques like mowing or burning, prairie plantings are considered to be cost-effective and low-maintenance. This study was undertaken to assess the impact of different maintenance strategies and especially the necessity of fire management on the development success of ornamental prairie plantings in central Europe. A four factorial split-plot-block design was set up for investigation of different mixtures of prairie species under varying management conditions (mow-only, mowing plus selective weeding, mowing plus weeding and burning) on two differing soil types (in-situ topsoil and in-situ topsoil with a graywacke gravel mulch top layer) over three years. Significant effects of maintenance strategy on mortality rates and vitality were documented for a number of target species, which responded species specifically, either being slightly affected by the burning or thriving on it. Those effects were mostly restricted to topsoil sites. A strong impact on weed species presence and abundance and resulting maintenance times was found on both soil types. On topsoil sites, mow-only treatment resulted in a short-term loss of the original planting due to extensive weed growth. Corresponding gravel mulch sites were generally less colonised and visually dominated by weeds. Differences between weeded and weeded plus burned sites were minor. Unexpectedly, weed species populations were mostly unaffected by the additional burning treatment, while maintenance times and costs increased. No overall benefit of fire management for the establishment of prairie plantings was documented. The most effective management combination proved to be mowing plus regular selective weeding measures on gravel mulched planting sites.

Highlights

For the past few decades in Germany, structurally diverse and sophisticated plantings- herbaceous plantings- have been declining in popularity, due to high maintenance costs and the lack of personnel with the relevant expertise [1,2]
At the level of species mixture, no significant effect of maintenance type on mortality rates was found between June and June 2013, either for the whole of the study layout or at the level of substrate units
At the individual species level, seven species showed a significant response to management type: Agastache foeniculum, Asclepias tuberosa, As. verticillata, Bouteloua curtipendula, Penstemon hirsutus, Schizachyrium scoparium and Sporobolus heterolepis

Summary

Introduction

For the past few decades in Germany, structurally diverse and sophisticated plantings- herbaceous plantings- have been declining in popularity, due to high maintenance costs and the lack of personnel with the relevant expertise [1,2]. Inspired by the knowledge gained from ecological analysis of natural plant communities [3,4], a new, more naturalistic approach to planting design was developed and is supported by an increased awareness of the beauty of native plant communities like meadows, calcareous grasslands or woodland edges [5]. To correspond with this ‘‘New German Style’’ [6], new maintenance concepts have been developed [7,8] and economized by a high degree of mechanization [9]. A prairie planting was believed to be a self-sustainable, highly attractive plant community that could be maintained with very little effort

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