INVESTIGADORES
ZALBA Sergio Martin
artículos
Título:
The influence of feral horses dung piles on surrounding vegetation. Management of Biological Invasions
Autor/es:
ZALBA, SERGIO M.; LOYDI, ALEJANDRO
Revista:
Management of Biological Invasions
Editorial:
Regional Euro-Asian Biological Invasions Centre - REABIC
Referencias:
Año: 2014 vol. 5 p. 73 - 79
Resumen:
The effect of grazing by large herbivores on
grassland communities has been extensively studied, however less is known about
changes associated with sites of high-intensity activity, such as dust bowls,
tracks, urine patches and dung piles, that might induce disproportionate
impacts to the directly affected areas and the surrounding vegetation. This
paper explores the changes associated with exotic feral horse dung piles in
relicts of natural grasslands in Argentine Pampas. We expected greater changes
in the composition of plant communities and a greater facilitation effect on
the establishment of invasive alien plants adjacent to the dung piles.
Characteristics of the vegetation surrounding dung piles were recorded in 100?e25 cm plots located 0¡V1.5 m from the
edge of the piles. We compared the immediate surroundings with reference plots
at 5 m. The diversity of plant species increased as distance from the edge
increased from 0¡V1.5 m; however, species richness was significantly higher in
the first meter next to dung piles than 5 m away. Percentage cover of bare
ground decreased further from the dung piles at both scales. Percentage cover of
woody plants was greater at greater distances from the manure, whereas
percentage cover of exotic plants was significantly higher next to the dung
piles. The reported changes could be related to concentration gradients of
nutrients liberated from the manure and/or to behaviour patterns of the horses,
which may avoid grazing in the immediate surroundings of dung piles. These
changes result in invasion windows facilitating the establishment and
subsequent dispersal of exotic plant species in grasslands.