The European bison (Bison bonasus), the largest mammal and one of the most threatened on the continent, may have an ideal refuge to survive in the forests of southern Spain in conditions of semi-freedom and in coexistence with other wild herbivores. A study published in the journal Biodiversity and , with the participation of the Universitat Autònoma de Barcelona (UAB) and the ConsellSuperior d' Investigacions Científiques (CSIC), has for the first time analyzed the comparative diet of three large herbivores, the European bison, the red deer ( Cervus elaphus) and the fallow deer (Dama dama), when they live together in the Mediterranean mountains.
The study was carried out in the El Encinarejo estate, with an extension of 1,000 ha and located in the Sierra d'Andújar (Jaén), and characterized by a typical Mediterranean mountain habitat with a predominance of oak groves and abundant presence of 'shrubs such as mastic, lavender and rosemary.
"The European bison is the largest living European mammal, a survivor of a past time when large herds of herbivores roamed freely in meadows and forests, shaped the landscape and promoted biodiversity", says Jordi Bartolomé, professor at the UAB and lead author of the study. The bovid was on the verge of extinction at the beginning of the 20th century, and is currently on the red list of threatened species of the International Union for ), so it is protected throughout Europe. The wide geographical distribution during the Holocene along the European continent, as well as the success of populations introduced in recent decades in different territories, have revealed the capacity and plasticity of the species to adapt to new habitats and characteristics broad bioclimatic.
"The creation of new reproductive centers in conditions of semi-freedom has become a strategy to guarantee the survival of the species while making it possible to apply the potential to restore and improve the biodiversity of these areas", says Jorge Cassinello, CSIC researcher at the Arid Zones Experimental Station (EEZA) and co-author of the study.
At the end of 2020, 18 specimens were introduced to the El Encinarejo estate, the southernmost distribution of the species to date. On the farm they live with other ungulate herbivores: around 400 deer and 200 fallow deer. To learn how these species use trophic resources, faecal 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 that woody plants are preferably consumed in autumn and winter, grasses in summer and legumes and herbs in spring. The woody component is the most abundant in the diet of the three species: it represents 81% of the plant fragments in deer droppings, 52% in bison and 38% in doe droppings.
"It is the first study that shows the consumption of mastic ( Pistacia lentiscus ) by European bison in all seasons", says Bartolomé. The comparison of the feeding behavior of the three species shows that bison consume significantly more grasses (21%), while legumes are more present in the doe's diet (32%). The deer, on the other hand, consumes less herbs (8%).
"The main conclusion we can draw is the existence of a distribution of trophic resources between the three species of herbivores when they live together in the same habitat, a fact that seems to evidence the 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 point out that, "beyond whether or not the European bison inhabited the Iberian Peninsula in the past (a fact that remains to be determined paleontologically), the time has come to implement effective conservation measures that allow biodiversity to increase and focus primarily in the ecosystem functions of the species, instead of their origin”.
