Ungulates alter plant cover without consistent effect on soil ecosystem functioning

• Published in: Agriculture, ecosystems & environment Vol. 326; p. 107796
• Main Authors: Ibañez-Alvarez, Miguel, Baraza, Elena, Serrano, Emmanuel, Romero-Munar, Antonia, Cardona, Carles, Bartolome, Jordi, Krumins, Jennifer Adams
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.03.2022
• Subjects: agriculture; animal husbandry; Capra hircus; Ecosystem services; environment; goats; Grazing exclusion; landscapes; meta-analysis; Microbial activity; soil ecosystems; Soil heterogeneity; Spain; Ungulate overabundance; vegetation cover; Spain; Microbial activity; Ecosystem services; Ungulate overabundance; Soil heterogeneity; Grazing exclusion
• ISSN: 0167-8809; 1873-2305
• DOI: 10.1016/j.agee.2021.107796

Shifts in animal husbandry and landscape use have significantly changed ungulate grazing effects on ecosystem functioning. These changes are now the subject of extensive research with respect to plant and soil communities, but the results of these studies are highly varied and context dependent. The objective of this study is to address contextual variation by holding all sampling methods and analytical approaches constant and analyse the effect of the feral goat (Capra hircus) population of Mallorca Island, Spain, on soil physical, chemical and biological characteristics across five controlled sites. Specifically, vegetation cover and soil properties in fenced plots excluded from ungulates were compared with adjacent grazed plots in five independent mountain areas of Mallorca. Soil microbial activity measured as Community-Level Physiological Profiles (CLPP) using EcoPlate™ increased when ungulates were excluded. However, all other physical and chemical measures of the soils did not vary significantly when we considered ungulate exclusion across all plots, and this may be caused by a soil community that is simply robust to the effects of the herbivores. Or, it may be due to the high heterogeneity that was detected among pair plots comparisons within each of the five sites. Indeed, we find more variability within a site than among our independent sites leading us to hypothesize that grazing does influence biogeochemical cycles, but it does it by increasing variability of the system in general. Our well-controlled multilevel meta-analysis confirms the notion that ungulate effects are highly context dependent, and soil heterogeneity makes resolving clear patterns very challenging. Apparently, context persistently drives the soil response more than the grazing itself, and this is seen even at very small scales. [Display omitted] •Ungulate land use is in transition, with global implications for grassland ecosystem stability.•We study ungulate effects on soils of 14 pair exclosure experiments in 5 independent areas.•Ungulate exclusion significantly affects plant community and soil microbial activity.•Physicochemical soil characteristics and OM degradation did not consistently change.•Ungulates exclusion effect was more heterogeneous within plots than among areas.