Unlike its Eurasian brown bear cousins, the Pyrenean brown bear is an endangered species. Due to their expansive roaming range, the Pyrenean bears play an important role in long distance plant dispersal, crucial to maintaining plant community dynamics, especially in light of environmental changes such as global warming.
The Pyrenean brown bear (Ursus arctos arctos) that lives in the mountainous border between France and Spain is an endangered species which totalled just 40 individuals in 2017.
Considerable efforts to increase its population are underway, protecting and preserving the bear which is one of the most endangered large carnivores in Europe.
In a study published in the journal Mammalia, researchers explored the bears’ potential as a long-distance seed disperser. The researchers monitored its presence by the brown bear network which allows the individual identification of the remaining resident bears.
These indices were used in the study to assess the plants bears feed upon and more specifically, the seeds that are dispersed. Bear faeces were crumbled for seed identification under a magnifying glass. Up to 47 different plants were identified, mainly forest shrubs and trees producing fleshy fruits like blueberries, raspberries and sorb apples.
In the second part of the study, the researchers coupled gut passage time and bear movement to assess potential seed dispersal distances. The gut passage time corresponding to the excretion of 50% of the seeds consumed an average of six hours for the Pyrenean brown bear.
Using GPS technology, the authors assessed that the bears cover distances ranging between 0.8 and 1.3 kilometres and up to a maximum of 7 kilometres. The study was carried out during the summer and autumn months – the peak time for fruit production.
The brown bear can thus disperse forest plants over 1 kilometre, which can be considered as long-distance dispersal events. Moreover, the brown bear appears to complement other mammals native to the Pyrenees like roe deer, red deer, the Pyrenean chamois and wild boar that disperse plants from open areas over shorter distances.
The study highlights the important, yet underrated role the Pyrenean brown bear plays in functioning ecosystems. Its role as a long-distance seed disperser in Southern Europe and the bear’s potential implication in the dispersal of rare endemic plant species is crucial to seed dispersal in Southern Europe.
Plant dispersal is crucial to maintaining the dynamics of plant communities and ecosystems, especially in the current context of rapid environmental changes such as global warming and landscape fragmentation. Further research and developments are needed.
Read the original article here
Aurélie Lalleroni, Pierre-Yves Quenette, Tanguy Daufresne, Maryline Pellerin, Christophe Baltzinger: Exploring the potential of brown bear (Ursus arctos arctos) as a long-distance seed disperser: a pilot study in South-Western Europe. 29.02.2016