Is the native deer Mazama gouazoubira threatened by competition for food with the exotic hare Lepus europaeus in the degraded Chaco in Córdoba, Argentina?

Using microhistological analysis of faeces, we studied the diets of the wild Chacoan Brown brocket deer (Mazama gouazoubira) and the exotic European hare (Lepus europaeus) by comparing plant species frequency in faeces with plant species availability. Research was conducted in the dry southern portion of South American Chaco, in forests subjected to livestock ranching in the north of Córdoba province, Argentina. The diet of the Brown brocket deer was more closely related to forage availability (C=0.82195) than the diet of the European hare (C=0.38565). Dicots comprised 90% of the Brown brocket deer diet and were preferred throughout the year, while gramineous species were consumed in low amount. In the diet of the European hare, gramineous species were frequent (65 to 87%) and preferred in every season but in winter, when dicots were consumed in higher proportions (92%). Differences in feeding habits and in habitat use would allow both herbivores to coexist; however, probable competition for food with the European hare during the dry period, in addition to habitat loss, threatens survival of the Brown brocket deer.