Towards precision grazing : spatio-temporal dynamics of the relation between cattle, vegetation, and arthropods

Abstract

Domestic livestock has largely replaced native mega-herbivores in shaping and maintaining grassland ecosystems and their function in temperate Europe. Because livestock grazing affects grassland biodiversity and functioning differently compared to free roaming large grazers, management adjustments are required to approximate natural processes as closely as possible without causing major economic losses. The spatiotemporal precision of remote sensing technology available today opens up opportunities to align agronomic and environmental interests. We evaluate the spatiotemporal scales at which cattle presence modulates vegetation biomass and the abundance of various arthropod taxa. We relate arthropod abundances and vegetation biomass to both static (stocking density at the field level) and dynamic (cattle presence in consecutive days before sampling at sub-field levels) grazing intensity in an extensive grazing system in central Germany. Grazing intensity at the field scale was a poor predictor of arthropod abundance, indicating a weak link to small-scale spatial heterogeneity, i.e. the major driver of local arthropod biodiversity. In contrast, most arthropod taxa responded more strongly to the presence of cattle than to the vegetation status across all spatiotemporal scales. This relationship was positive throughout. The relevance of temporal heterogeneity in the presence of cattle as a key driver of spatial heterogeneity makes a striking point for cattle ecosystem engineering. Accounting for temporal variability opens a promising approach to precision grazing that balances economic and environmental interests.