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

PASCUAL, J.; ALBERTI, J.; DALEO, P.; IRIBARNE, O.

JOURNAL OF VEGETATION SCIENCE

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2017 vol. 28 p. 1028 - 1035

1100-9233

Question:Do trampling and herbivory by small mammals affect salt marshesphysical and biological properties?Location:Upper salt marsh at the Mar Chiquita coastal lagoon (37º 44´ 52´´S, 57º 26´ 6´´ W,Argentina).Methods:A field experiment was placed from autumn to early summer in runwaysmade by the wildGuinea pig Caviaaperea.Segments of runways were randomly assigned to different treatments:control (herbivory and trampling), total exclusion (without herbivoryor trampling) and reduced trampling (herbivory without trampling).After eight months of experiment, soil hardness, runway depth,maximum plant height, aboveground biomass, plant assemblages,diversity and richness were measured and compared between treatments.Results:Runways of C. apereacovered 14.5 % of the area. Through trampling, C.aperea compacted the soil, increasing soil hardnessand runway depth. Herbivory, in turn, reduced aboveground biomass andplant 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 todrive soil compaction, an effect previously described only for largemammals. Results also show that small mammals can control salt marshprimary production, reduce species richness and modify thecomposition of plant species through herbivory. Small mammalherbivores, thus, can modify physical and biological properties ofsalt marsh communities through both trophic and non-trophicmechanisms.