Grazing in temporary paddocks with hardy breed horses (Konik polski) improved species-rich grasslands restoration in artificial embankments of the Rhône river (Southern France)

Cannelle Moinardeau,François Mesléard,Hervé Ramone,Thierry Dutoit

doi:10.1016/j.gecco.2021.e01874

Abstract

Extensive horse grazing with hardy breeds is largely used in conservation management for restoring species-rich semi-natural grasslands in Europe. As an example, the Donzère-Mondragon Rhône river embankments (south-eastern France) where horse grazing with Konik polski succeeded to maintain high species richness in patches of open and short grassland, but failed for patches of tall grassland dominated by the grass tussock species Brachypodium phoenicoides . In response, an increase of herd density by the creation of temporary paddocks was applied in tall grassland patches. Grazing pressure over time between patches was estimated via GPS fixed to mares, biomass, plant species richness measurements and from multispectral photographs, the normalized Difference Vegetation Index (NDVI) was calculated. Finally, telemetric data were collected. We wondered if the use of extensive horse grazing with temporary paddocks occupation, increase plant species richness. After three years, our results show that the increase in stocking rate enabled a significant increase of plant species richness in the tall grassland patches, with a significant decline of B. phoenicoides in all paddocks. The NDVI was strongly correlated with herbaceous biomass and plant species richness, while the number of GPS points indicating the position of the mares was higher in areas where the NDVI was high. These results are discussed for improving horse grazing conservation systems efficiency on grasslands established in anthropized sites such as embankments and the use of the NDVI as an appropriate tool to help decision-making for large-scale applications.

Highlights

Extensive grazing, defined by Allen et al, (2011) as grazing management that uses relatively large land areas per animal, is commonly used in protected areas where the maintenance of open habitat is a major goal (Olff and Ritchie 1998; van Wieren and Bakker 1998; Rosenthal et al 2012; Wallis De Vries et al 2007; Török et al 2016, for review)
We addressed the two following questions: Jou - Does the use of extensive horse grazing by hardy breed horses (Konik polski) in the form of temporary paddocks occupation, increase plant species richness especially in tall vegetation patches? - Is there a differential use of space by horses corresponding to differences in Normalized Difference Vegetation Index (NDVI) index?
To accurately reflect the diversity of vegetation stages encountered before the re-distribution of the horses in 2014, we placed randomly five quadrats (2 x 2 m) in each of the three enclosures grazed by the horses and for each herbaceous vegetation patches previously identified via aerial photographs and field observations (Moinardeau et al 2016; Moinardeau et al 2019): open grassland (OG) composed by annual plant species with bare zones representing areas with silt and clay deposits; short grassland (SG) covered by 10–20 cm high herbaceous perennial vegetation and annual species ; tall grassland (TG) dominated by the species Brachypodium phoenicoides (L.) Roem. & Schult. 20–30 cm in height; and nongrazed tall grassland (> 30 cm) outside the grazed areas, used as controls (C)

Summary

Introduction

Extensive grazing, defined by Allen et al, (2011) as grazing management that uses relatively large land areas per animal, is commonly used in protected areas where the maintenance of open habitat is a major goal (Olff and Ritchie 1998; van Wieren and Bakker 1998; Rosenthal et al 2012; Wallis De Vries et al 2007; Török et al 2016, for review). Pro In the present field experiment, we studied over a three-year period how changes in the - stocking method of extensive grazing by hardy breed horses (Konik polski), in the form of re paddocks temporary occupation modify the herbaceous vegetation of an anthropized area P (artificial embankments). We addressed the two following questions: Jou - Does the use of extensive horse grazing by hardy breed horses (Konik polski) in the form of temporary paddocks occupation, increase (in the short time – 3 years) plant species richness especially in tall vegetation patches? We addressed the two following questions: Jou - Does the use of extensive horse grazing by hardy breed horses (Konik polski) in the form of temporary paddocks occupation, increase (in the short time – 3 years) plant species richness especially in tall vegetation patches? - Is there a differential use of space by horses corresponding to differences in NDVI index?

Study site

Use of space by the horses

Findings

Discussion