The European bison (Bison bonasus), the largest mammal and one of the most endangered on our continent, may have in the forests of southern Spain an ideal refuge for its survival in semi-free conditions and coexistence with other wild herbivores. A study published in the journal Biodiversity and Conservation, with the participation of the Autonomous University of Barcelona (UAB) and the Higher Council for Scientific Research (CSIC), has analyzed for the first time the comparative diet of three large herbivores, the European bison, the common deer (Cervus elaphus) and fallow deer (Dama dama), when they coexist in the Mediterranean mountains.
The study has been carried out on the El Encinarejo farm, with an area of 1,000 ha and located in the Andújar mountain range (Jaén), and characterized by a typical Mediterranean forest habitat with a predominance of mature holm oak forests and abundant presence of shrubs such as mastic, lavender and rosemary.
"The European bison is the largest living European mammal, a survivor of a bygone era in which large herds of herbivores roamed freely in meadows and forests, shaping the landscape and promoting biodiversity," says Jordi Bartolomé, professor at the Autonomous University of Barcelona. and lead author of the study.
This bovid was almost extinct at the beginning of the 20th century, and is currently on the IUCN red list of threatened species, so it is protected throughout Europe.
Its wide geographical distribution during the Holocene throughout the European continent, as well as the success of populations introduced in recent decades in different European territories, have revealed the capacity and plasticity of the species to adapt to new habitats and a wide bioclimatic range. .
"The creation of new reproductive nuclei in conditions of semi-freedom has become a strategy to guarantee the survival of the species, while allowing its potential to be applied to restore and improve the biodiversity of these areas," says Jorge Cassinello, CSIC researcher. at the Experimental Station for Arid Zones (EEZA) and co-author of the study.
At the end of 2020, 18 specimens were introduced to the El Encinarejo farm, in the Andújar mountain range (Jaén), the southernmost distribution of the species to date. On the farm, other herbivorous ungulates coexist with the bison: about 400 deer and 200 fallow deer. To know how these species use trophic resources, fecal samples were collected seasonally during 2021. The microhistological analysis technique was used to determine the percentage of epidermal fragments of the main functional groups (woody plants, grasses, legumes) of each sample. .
The results show significant differences between animal species and seasons of the year. Thus, woody plants are preferably consumed in autumn and winter, grasses in summer and legumes and herbaceous plants in spring. The woody component is the most abundant in the diet of the three species, specifically it represents 81% of the plant fragments present in deer feces, 52% in bison feces, and 38% in fallow deer feces.
"This is the first study that shows the consumption of mastic (Pistacia lentiscus) by European bison, and the abundant presence in their diet during all seasons indicates that it is a very important food source," says Bartolomé.
The comparison of the feeding behavior of the three herbivore species shows that the bison consumes significantly more grasses (21%), while legumes are more present in the diet of the fallow deer (32%). The common deer, for its part, consumes less herbaceous plants than the other two species (8%).
"The main conclusion that we can draw from this work is the existence of a distribution of trophic resources between the three species of herbivores when they coexist in the same habitat, which seems to show their ability to live together and, on the other hand, the ability of the bison to adapt to the bioclimatic conditions of the Mediterranean mountains," concludes Cassinello.
The authors of this work finally point out that, "regardless of whether or not the European bison lived in the Iberian Peninsula in the past (a fact yet to be determined paleontologically), and as other researchers propose, the time has come to implement measures to increase and maintain biodiversity, and to focus primarily on the ecosystem functions of species, rather than their origin.
