Register      Login
The Rangeland Journal The Rangeland Journal Society
Journal of the Australian Rangeland Society
RESEARCH ARTICLE

Impacts of horse grazing on botanical composition and diversity in different types of heathland

Carlos López López A , Rocío Rosa García A , Luis M. M. Ferreira B , Urcesino García A , Koldo Osoro A and Rafael Celaya A C
+ Author Affiliations
- Author Affiliations

A Servicio Regional de Investigación y Desarrollo Agroalimentario (SERIDA), 33300 Villaviciosa, Asturias, Spain.

B CITAB – Centre for the Research and Technology of Agro-Environmental and Biological Sciences, Universidade de Trás-os-Montes e Alto Douro, 5000-801 Vila Real, Portugal.

C Corresponding author. Email: rcelaya@serida.org

The Rangeland Journal 39(4) 375-385 https://doi.org/10.1071/RJ17079
Submitted: 25 May 2017  Accepted: 2 October 2017   Published: 27 October 2017

Abstract

Plant dynamics under horse grazing was studied in a three-year field experiment in heather-gorse shrublands in NW Spain. The experimental design consisted of three vegetation types with four replicates (paddocks): (1) heather (Ericaceae)-dominated (H), (2) gorse (Ulex gallii Planch.)-dominated (G), and (3) co-dominated by gorse and heath-grasses (GG). Each paddock (1.2 ha) was grazed from May to October by two crossbred mature mares (310 ± 52 kg bodyweight), one dry and one lactating (plus foal). Two other paddocks (one in H and one in GG) were excluded from grazing. Plant cover and height were sampled three times a year (spring, summer, and autumn) with a point-quadrat method. Floristic composition and diversity were annually sampled at 10 25-m2 quadrats per paddock. Data were subjected to mixed models for repeated-measures and redundancy analyses. Horse grazing resulted in overall increases (P < 0.001) in heather and herbaceous cover (from 13% to 27%, and from 16% to 23%, respectively), and decreases (P < 0.001) in gorse cover and height (from 35% to 17%; from 30 to 25 cm), with scarce differences among vegetation types. Floristic diversity (species richness and Shannon index) increased more over time in grazed than in ungrazed paddocks. Redundancy analyses revealed that grazing effects on plant species assemblages depended on vegetation type, and that plant communities evolved differently between grazing treatments for both abundance and frequency data. Some herbaceous species characteristic of heathlands were favoured by horse grazing. Horse grazing reduced gorse dominance in G and GG vegetation, controlling excessive accumulation of combustible material and reducing fire risk, and promoted the presence of species of conservation interest, so it offers a promising management tool for the restoration of heathlands and their biodiversity.

Additional keywords: Equus ferus caballus, floristic diversity, heather, plant dynamics, restoration, Ulex gallii.


References

Aldezabal, A., Mandaluniz, N., and Laskurain, N. A. (2013). Gorse (Ulex spp.) use by ponies in winter: Is the spatial pattern of browsing independent of the neighbouring vegetation? Grass and Forage Science 68, 49–58.
Gorse (Ulex spp.) use by ponies in winter: Is the spatial pattern of browsing independent of the neighbouring vegetation?Crossref | GoogleScholarGoogle Scholar |

Beever, E. A., and Brussard, P. F. (2000). Examining ecological consequences of feral horse grazing using exclosures. Western North American Naturalist 60, 236–254.

Benavides, R., Celaya, R., Ferreira, L. M. M., Jáuregui, B. M., García, U., and Osoro, K. (2009a). Grazing behaviour of domestic ruminants according to flock type and subsequent vegetation changes on partially improved heathlands. Spanish Journal of Agricultural Research 7, 417–430.
Grazing behaviour of domestic ruminants according to flock type and subsequent vegetation changes on partially improved heathlands.Crossref | GoogleScholarGoogle Scholar |

Benavides, R., Roig, S., and Osoro, K. (2009b). Potential productivity of forested areas based on a biophysical model. A case study of a mountainous region in northern Spain. Annals of Forest Science 66, 1–10.
Potential productivity of forested areas based on a biophysical model. A case study of a mountainous region in northern Spain.Crossref | GoogleScholarGoogle Scholar |

Bokdam, J., and Gleichman, J. M. (2000). Effects of grazing by free-ranging cattle on vegetation dynamics in a continental north-west European heathland. Journal of Applied Ecology 37, 415–431.
Effects of grazing by free-ranging cattle on vegetation dynamics in a continental north-west European heathland.Crossref | GoogleScholarGoogle Scholar |

Bullock, J. M., and Pakeman, R. J. (1997). Grazing of lowland heath in England: management methods and their effects on heathland vegetation. Biological Conservation 79, 1–13.
Grazing of lowland heath in England: management methods and their effects on heathland vegetation.Crossref | GoogleScholarGoogle Scholar |

Celaya, R., Martínez, A., and Osoro, K. (2007). Vegetation dynamics in Cantabrian heathlands associated with improved pasture areas under single or mixed grazing by sheep and goats. Small Ruminant Research 72, 165–177.
Vegetation dynamics in Cantabrian heathlands associated with improved pasture areas under single or mixed grazing by sheep and goats.Crossref | GoogleScholarGoogle Scholar |

Celaya, R., Ferreira, L. M. M., García, U., Rosa García, R., and Osoro, K. (2011). Diet selection and performance of cattle and horses grazing in heathlands. Animal 5, 1467–1473.
Diet selection and performance of cattle and horses grazing in heathlands.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BC38vovFSjsQ%3D%3D&md5=fb61a52c88cdd0fb2f0e955203baecbdCAS |

Commission of the European Communities (2009). ‘Towards a better targeting of the aid to farmers in areas with natural handicaps.’ COM (2009) 161 (EUR-Lex: Brussels.) Available at: http://eur-lex.europa.eu/legal-content/en/ALL/?uri=CELEX:52009DC0161 (accessed 24 May 2017).

Davies, K. W., Collins, G., and Boyd, C. S. (2014). Effects of feral free-roaming horses on semi-arid rangeland ecosystems: an example from the sagebrush steppe. Ecosphere 5, art127.
Effects of feral free-roaming horses on semi-arid rangeland ecosystems: an example from the sagebrush steppe.Crossref | GoogleScholarGoogle Scholar |

Fagúndez, J. (2016). Grazing effects on plant diversity in the endemic Erica mackayana heathland community of north-west Spain. Plant Ecology & Diversity 9, 207–217.
Grazing effects on plant diversity in the endemic Erica mackayana heathland community of north-west Spain.Crossref | GoogleScholarGoogle Scholar |

Fernández Prieto, J. A., Cires, E., Bueno, Á., Vázquez, V. M., and Nava, H. S. (2014). ‘Catálogo de las Plantas Vasculares del Principado de Asturias.’ (Ayuntamiento de Gijón, Jardín Botánico Atlántico: Gijón, Spain.)

Ferreira, L. M. M., Celaya, R., Benavides, R., Jáuregui, B. M., García, U., Santos, A. S., Rosa García, R., Rodrigues, M. A. M., and Osoro, K. (2013). Foraging behaviour of domestic herbivore species grazing on heathlands associated with improved pasture areas. Livestock Science 155, 373–383.
Foraging behaviour of domestic herbivore species grazing on heathlands associated with improved pasture areas.Crossref | GoogleScholarGoogle Scholar |

Fleurance, G., Duncan, P., Farruggia, A., Dumont, B., and Lecomte, T. (2011). Impact du pâturage équin sur la diversité floristique et faunistique des milieux pâturés. Fourrages (Versailles) 207, 189–199.

Gordon, I. J. (1989). Vegetation community selection by ungulates on the isle of Rhum. II. Vegetation community selection. Journal of Applied Ecology 26, 53–64.
Vegetation community selection by ungulates on the isle of Rhum. II. Vegetation community selection.Crossref | GoogleScholarGoogle Scholar |

Grant, S. A. (1981). Sward components. In: ‘Sward Measurement Handbook’. (Eds J. Hodgson, R. D. Baker, A. Davies, A. S. Laidlaw and J. D. Leaver.) pp. 71–92. (British Grassland Society: Hurley, Maidenhead, Berkshire, UK.)

Grime, J. P. (2002). ‘Plant Strategies, Vegetation Processes, and Ecosystem Properties.’ 2nd edn. (John Wiley and Sons: Chichester, UK.)

Jáuregui, B. M., Celaya, R., García, U., and Osoro, K. (2007). Vegetation dynamics in burnt heather-gorse shrublands under different grazing management with sheep and goats. Agroforestry Systems 70, 103–111.
Vegetation dynamics in burnt heather-gorse shrublands under different grazing management with sheep and goats.Crossref | GoogleScholarGoogle Scholar |

Jáuregui, B. M., García, U., Osoro, K., and Celaya, R. (2009). Sheep and goat grazing effects on three Atlantic heathland types. Rangeland Ecology and Management 62, 119–126.
Sheep and goat grazing effects on three Atlantic heathland types.Crossref | GoogleScholarGoogle Scholar |

Kent, M., and Coker, P. (1992). ‘Vegetation Description and Analysis. A Practical Approach.’ (Belhaven Press: London.)

Lepš, J., and Šmilauer, P. (2003). ‘Multivariate Analysis of Ecological Data Using CANOCO.’ (Cambridge University Press: Cambridge, UK.)

López López, C., Ferreira, L. M. M., García, U., Moreno-Gonzalo, J., Rodrigues, M. A. M., Osoro, K., Ferre, I., and Celaya, R. (2017). Diet selection and performance of horses grazing on different heathland types. Animal 11, 1708–1717.
Diet selection and performance of horses grazing on different heathland types.Crossref | GoogleScholarGoogle Scholar |

Loucougaray, G., Bonis, A., and Bouzillé, J. B. (2004). Effects of grazing by horses and/or cattle on the diversity of coastal grasslands in western France. Biological Conservation 116, 59–71.
Effects of grazing by horses and/or cattle on the diversity of coastal grasslands in western France.Crossref | GoogleScholarGoogle Scholar |

Marion, B., Bonis, A., and Bouzillé, J. B. (2010). How much does grazing-induced heterogeneity impact plant diversity in wet grasslands? Ecoscience 17, 229–239.
How much does grazing-induced heterogeneity impact plant diversity in wet grasslands?Crossref | GoogleScholarGoogle Scholar |

Menard, K., Duncan, P., Fleurance, G., Georges, J. Y., and Lila, M. (2002). Comparative foraging and nutrition of horses and cattle in European wetlands. Journal of Applied Ecology 39, 120–133.
Comparative foraging and nutrition of horses and cattle in European wetlands.Crossref | GoogleScholarGoogle Scholar |

Milchunas, D. G., and Lauenroth, W. K. (1993). Quantitative effects of grazing on vegetation and soils over a global range of environments. Ecological Monographs 63, 327–366.
Quantitative effects of grazing on vegetation and soils over a global range of environments.Crossref | GoogleScholarGoogle Scholar |

Mouissie, A. M., Vos, P., Verhagen, H. M. C., and Bakker, J. P. (2005). Endozoochory by free-ranging, large herbivores: Ecological correlates and perspectives for restoration. Basic and Applied Ecology 6, 547–558.
Endozoochory by free-ranging, large herbivores: Ecological correlates and perspectives for restoration.Crossref | GoogleScholarGoogle Scholar |

Osoro, K., Ferreira, L. M. M., García, U., Jáuregui, B. M., Martínez, A., Rosa García, R., and Celaya, R. (2013). Diet selection and performance of sheep and goats grazing on different heathland vegetation types. Small Ruminant Research 109, 119–127.
Diet selection and performance of sheep and goats grazing on different heathland vegetation types.Crossref | GoogleScholarGoogle Scholar |

Osoro, K., Ferreira, L. M. M., García, U., Martínez, A., and Celaya, R. (2017). Forage intake, digestibility and performance of cattle, horses, sheep and goats grazing together on an improved heathland. Animal Production Science 57, 102–109.
Forage intake, digestibility and performance of cattle, horses, sheep and goats grazing together on an improved heathland.Crossref | GoogleScholarGoogle Scholar |

Putman, R. J., Pratt, R. M., Ekins, J. R., and Edwards, P. J. (1987). Food and feeding behaviour of cattle and ponies in the New Forest, Hampshire. Journal of Applied Ecology 24, 369–380.
Food and feeding behaviour of cattle and ponies in the New Forest, Hampshire.Crossref | GoogleScholarGoogle Scholar |

Rigueiro-Rodríguez, A., Mouhbi, R., Santiago-Freijanes, J. J., González-Hernández, M. P., and Mosquera-Losada, M. R. (2012). Horse grazing systems: understory biomass and plant biodiversity of a Pinus radiata stand. Scientia Agricola 69, 38–46.
Horse grazing systems: understory biomass and plant biodiversity of a Pinus radiata stand.Crossref | GoogleScholarGoogle Scholar |

Rook, A. J., Dumont, B., Isselstein, J., Osoro, K., WallisDeVries, M. F., Parente, G., and Mills, J. (2004). Matching type of livestock to desired biodiversity outcomes in pastures – a review. Biological Conservation 119, 137–150.
Matching type of livestock to desired biodiversity outcomes in pastures – a review.Crossref | GoogleScholarGoogle Scholar |

Rosa García, R., Fraser, M. D., Celaya, R., Ferreira, L. M. M., García, U., and Osoro, K. (2013). Grazing land management and biodiversity in the Atlantic European heathlands: a review. Agroforestry Systems 87, 19–43.
Grazing land management and biodiversity in the Atlantic European heathlands: a review.Crossref | GoogleScholarGoogle Scholar |

Ter Braak, C. J. F., and Šmilauer, P. (2002). ‘CANOCO Reference Manual and CanoDraw for Windows User’s Guide: Software for Canonical Community Ordination (version 4.5).’ (Microcomputer Power: Ithaca, NY.)

Torrano, L., and Valderrábano, J. (2004). Review. Impact of grazing on plant communities in forestry areas. Spanish Journal of Agricultural Research 2, 93–105.
Review. Impact of grazing on plant communities in forestry areas.Crossref | GoogleScholarGoogle Scholar |