Invasion of Gleditsia triacanthos in corridors of Pampean water courses and its effect on Myocastor coypus distribution

Abstract

Honey Locust (Gleditsia triacanthos) is a tree autochthonous of USA. It is considered invasive in Pampean Grassland. Nowadays, exist few punctual selective controls or massive not selective controls, but they have high cost or high environmental impact. G. triacanthos forms closed forest on corridors of watercourses that affects native biota and constitutes a threat for remnants of autochthonous ecosystems. The aim of this work was to determine the environmental characteristics associated with the presence of G. triacanthos on the coasts of rivers and streams of Pampas Region; and to examine how its presence affects the presence of Myocastor coypus, a native rodent. We evaluated 14 streams and rivers and examined the associations between presence-absence of G. triacanthos arboreal groups, environmental characteristics of watercourse corridors and presence of signs of coypu activity. We found groups of G. triacanthos in 43% of almost 80% of the water courses. Results indicate that its presence was associated significantly (1) with environmental characteristics: width of the course, height and slope of the coast and land use boundaries, which might help to design alternative plans of control; and (2) with the absence of coypu, probably due to deterioration of autochthonous habitat.