Grizzly bears help huckleberries thrive in a changing climate

Who knew that there’s a significant bond between grizzly bears and huckleberries? Their interaction transcends the simple paradigm of consumption, offering a deep dive into the realm of plant ecology.

In a recent study led by scientists from the University of British Columbia’s Vancouver and Okanagan campuses, an eye-opening revelation was made about grizzly bears.

Grizzly bears feasting on huckleberries

The study was focused on the behavior of grizzly bears in the Canadian Rocky Mountains during the summer season. The researchers found that while these bears enjoy a feast of huckleberries, they are doing more for the development of these plants than just eating.

“Bears don’t just eat huckleberries – they help them grow in new places,” noted Aza Fynley Kuijt, the study’s lead researcher from UBC’s Faculty of Forestry.

“Our findings show that this mutual relationship is crucial for both species, especially as climate change shifts suitable habitats for huckleberries.”

Bears as long-distance seed dispersers

At the heart of the study, an aspect of plant ecology known as endozoochory was examined.

Simply put, endozoochory is the process where animals eat fruits containing seeds and later disperse those seeds over large areas through their droppings. In the case of grizzly bears and huckleberries, the researchers found this process to be highly beneficial.

When bears eat huckleberries, the seeds travel through their digestive system and are deposited far from the original plant. This not only spreads the seeds to new areas but also improves their chances of germination, helping the huckleberries grow in fresh and potentially better-suited habitats.

The team found that seeds which pass through a grizzly bear’s digestive system are much more likely to sprout and grow into huckleberry plants. These seeds have a germination rate of up to 28.5%, compared to only 0.2% for seeds that remain inside uneaten berries.

Why the difference? The digestive process removes the berry pulp, which contains substances that prevent the seeds from sprouting (known as germination inhibitors).

By breaking down this barrier, the bears’ digestion enhances the seeds’ ability to grow, making the process essential for the huckleberries’ reproduction and survival.

Grizzly bears, huckleberries, and ecosystems

Imagine the movement of seeds being akin to an expansive, rippling shadow, journeying up to seven kilometers (4.3 miles) from their original feeding site.

This is what the researchers discovered from the 74 collared grizzly bears observed in the study. Up to 50% of the seeds consumed by the bears were spread about a kilometer from their source.

With huckleberries being a vital food source for grizzly bears during the late summer, this seed dispersal mechanism holds profound implications. It helps the huckleberries adapt to changing climates by infiltrating new, suitable habitats.

Human activities such as urban development, resource extraction, and increased recreational activities in bear habitats could potentially disrupt this crucial ecological partnership.

Protecting ecological processes

This study highlights the intricate connections between large mammals and their environments.

“Wildlife conservation is not just about protecting certain species, but about looking after ecological processes and relationships,” said Clayton Lamb, co-author and UBC Okanagan biologist.

“As we show here, looking after grizzly bears and movement corridors can also help huckleberries, which people and bears both adore.”

Conservation efforts for grizzly bears

Grizzly bears, a subspecies of the brown bear, are iconic symbols of North American wilderness. Known for their size and strength, adult males can weigh between 300 to 800 pounds, while females are slightly smaller.

These omnivores have a diverse diet that includes plants, insects, fish, and mammals, but berries play a critical role in their nutrition during late summer and fall.

Grizzlies are highly intelligent and exhibit complex behaviors, such as tool use and strategic hunting. They rely heavily on large home ranges for survival, often spanning hundreds of square kilometers.

However, habitat loss and fragmentation pose significant threats to their populations. Conservation efforts focus on creating wildlife corridors to connect isolated habitats, ensuring genetic diversity and long-term survival.

Interestingly, beyond huckleberry seed dispersal, grizzly bears also play a role in soil enrichment. By digging for roots or preying on animals, they disturb the soil, aiding in nutrient cycling.

This behavior benefits plant growth and contributes to overall ecosystem health. Their status as a keystone species highlights their importance in maintaining ecological balance.

The study is published in the journal PLOS ONE.

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