Herbivory and trampling by small mammals modify soil properties and plant assemblages

PASCUAL, JESÚS; ALBERTI, JUAN; DALEO, PEDRO; IRIBARNE, OSCAR

JOURNAL OF VEGETATION SCIENCE

WILEY-BLACKWELL PUBLISHING, INC

Año: 2017

1100-9233

Methods: A field experiment was placed from autumn to early summer in runways made bythe wild Guinea pig Cavia aperea. Segments of runways were randomly assigned to differenttreatments: control (herbivory and trampling), total exclusion (without herbivory ortrampling) and reduced trampling (herbivory without trampling). After eight months ofexperiment, soil hardness, runway depth, maximum plant height, aboveground biomass, plantassemblages, diversity and richness were measured and compared between treatments.Results: Runways of C. aperea covered 14.5 % of the area. Through trampling, C. apereacompacted the soil, increasing soil hardness and runway depth. Herbivory, in turn, reducedaboveground biomass and plant species richness, and affected species composition. Both,herbivory and trampling decreased the maximum plant height.Conclusion: Our results show how small herbivores, through trampling, are able to drive soilcompaction, an effect previously described only for large mammals. Results also show thatsmall mammals can control salt marsh primary production, reduce species richness andmodify the composition of plant species through herbivory. Small mammal herbivores, thus,can modify physical and biological properties of salt marsh communities through both trophicand non-trophic mechanisms.