A recent study has shed light on the foraging habits of Andean bears (Tremarctos ornatus), revealing that these elusive animals – also known as 'spectacled bears' due to the distinctive white markings around their eyes – carefully select feeding sites to optimise nutrition while steering clear of areas with livestock.
The research focused on high-altitude puna grasslands in and around Peru’s Parque Nacional del Manu (Manu National Park), where the Andean bears feed heavily on bromeliads — a group of flowering plants that form a vital part of their diet.
Classified as vulnerable by the IUCN, the bears face threats from habitat loss, climate change and human-wildlife conflict. The findings, Led by Nicholas Pilfold from the San Diego Zoo Wildlife Alliance and published in the journal PLOS ONE, highlight the importance of conserving grasslands bordering cloud forests, which serve as critical habitats for the bears.
Tracking spectacled bears
Researchers surveyed two species of bromeliad, Puya leptostachya and Puya membranacea, in the puna grasslands – defined by the authors as a mix of "ephemeral peat bogs and waterlogged soils in glacially carved depressions, and drier steep slopes with stiff perennial bunch grasses."
By examining dug-up and partially eaten plants – a tell-tale sign of Andean bear activity – they identified where the bears had been foraging. Trail cameras confirmed the bears' presence at these sites, though intriguingly, the animals were found to forage in only 16.7% of available bromeliad patches.
The study, based on the largest ever collection of field data on the bear's feeding behaviour in high-elevation grasslands, discovered that their foraging habits were influenced by seasonal changes. During the dry season, they targeted younger, more tender bromeliad plants, which are likely more nutritious and easier to digest. Andean bears showed a clear preference for bromeliads growing on steep, east-facing slopes at the forest’s edge – areas that offer both food and relative safety from human disturbances.
Bears vs cattle – finding a balance
Interestingly, the researchers found that the bears rarely ventured into areas outside the park where livestock graze. However, they did forage in former grazing areas that had been left undisturbed for several decades, suggesting that Andean bears can reclaim lost habitat if given the opportunity.
This adaptability could play a crucial role in the species’ survival, especially if conservation efforts focus on restoring these high-altitude grasslands, say the team.
The authors urge conservation managers to consider the impact of livestock grazing on these ecosystems, ensuring that measures are in place to balance human activities with the needs of wildlife.
Main image: Parque Nacional del Manu, Peruvian Andes/Getty
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