How Mountain Lions Shape the Santa Cruz Mountains

Explore the hidden ecological connections that keep our forests healthy — and what could happen if the region’s apex predator disappeared.

Mountain lions are famously elusive, yet their influence extends throughout the Santa Cruz Mountains. As the region’s apex predator, they shape the behavior of deer, coyotes, and countless other species, helping maintain the ecological relationships that keep forests healthy and resilient. These hidden connections remind us that local plants and animals — humans included — are part of an intricate web of life. 

So, what might happen if mountain lions disappeared from the Santa Cruz Mountains? This short video explores one scientifically plausible scenario.

Illustrations by Matt Twombly

Every species plays a role in this web. Deer feed on young trees. Coyotes compete with smaller predators. Oaks provide food and shelter for hundreds of species. Together, these interactions create a dynamic ecosystem where changes to one species can have ripple effects. When a chain reaction is the result of adding or removing a top predator, it’s called a trophic cascade.

Healthy food webs are important for all of us. They support cleaner water, healthier forests, greater biodiversity, and ecosystems that are better able to withstand wildfire and other impacts of climate change.

HOW LIKELY IS THE SCENARIO IN THE VIDEO?

Real ecosystems are extraordinarily complex, and it’s tough to predict exactly how they might respond to losing any single species. Weather, wildfire, disease, human activity, and the countless interactions among plants and animals all influence what happens next. Some changes may occur quickly, while others could take years — or even decades — to unfold. 

Rather than forecasting the future, this animation illustrates the important role mountain lions play in our local landscapes and why protecting healthy, connected ecosystems benefits us all.

MOUNTAIN LION ECOLOGY: A CLOSER LOOK

What is a food web?

A food web is a network of feeding relationships that connects plants, animals, fungi, and other organisms. Unlike a simple food chain, food webs show that most species rely on many different sources of food and interact with multiple other species. These connections help explain why changes to one part of an ecosystem can have far-reaching effects.

Why are mountain lions apex predators?

Apex predators sit at the top of the food web, meaning they have few or no natural predators as adults. In addition to reducing prey populations, they influence where and how other animals move, helping shape ecosystems in ways scientists are still uncovering.

How do mountain lions affect coyotes?

Mountain lions and coyotes have a surprisingly complex relationship. Coyotes often scavenge deer killed by mountain lions, and the two predators also compete for some of the same smaller prey. Mountain lions sometimes kill coyotes as well. 

Research from Jasper Ridge Biological Preserve suggests that the biggest effect may be on coyote behavior rather than their numbers. Where mountain lions are present, coyotes may spend less time in groups, shift when they’re most active, and move more frequently across the landscape to avoid encounters. If mountain lions disappeared, these behaviors could change, with potential ripple effects for the smaller mammals, birds, and other wildlife who coyotes interact with.

Which animals rely on mountain lion kills for food?

A mountain lion’s role in the ecosystem doesn’t end with the hunt. After it has finished feeding, the remaining carcass provides food for a variety of scavengers, including coyotes, turkey vultures, ravens, foxes, insects, and microorganisms. These species, in turn, help break down organic matter and return nutrients to the soil, supporting the growth of plants and fungi.

How do scientists study trophic cascades?

Because ecosystems are so complex, scientists rarely rely on a single study. Instead, they combine long-term field observations, experiments, historical records, wildlife monitoring, and computer models to understand how species interact. Together, these approaches reveal patterns that may take decades to emerge.

What are some other well-known trophic cascades?

One of the best-known examples comes from Yellowstone National Park. Before wolves returned to the landscape, elk often lingered along streams and in young forests, heavily browsing willows and aspens. After wolf reintroduction, elk became more mobile and avoided some of these high-risk areas. In many places, this allowed streamside vegetation, like willow trees, to recover, benefiting beavers, birds, stream health, and other wildlife. Still, ecosystems are complex, and interactions amongst beavers, grizzly bears, wolves, elk, climate, and vegetation may also have contributed to the observed changes. Scientists have documented similar trophic cascades in kelp forests, rivers, grasslands, and forests around the world. 

What predators have already disappeared from coastal California?

Mountain lions are the region’s last remaining apex predator. Grizzly bears and gray wolves once roamed much of California before human activities like hunting and development drove them to local extinction. At the same time, logging, agriculture, urban development, and fire suppression dramatically reshaped local ecosystems. Because these changes happened over generations, it’s difficult to know exactly what these landscapes once looked like — a challenge ecologists sometimes describe as a “shifting baseline.”

How might climate change affect mountain lions?

Climate change is expected to alter habitats, shift where prey species live, increase the frequency of severe wildfires, and make it harder for wildlife to move across fragmented landscapes. Protecting connected habitats allows mountain lions and many other species to adapt as conditions change.

Can people and mountain lions coexist?

Yes. Mountain lions naturally avoid people, and conflicts are relatively uncommon. Protecting connected habitat, using wildlife-friendly fencing, supervising pets and livestock, and giving wildlife space are all important tools that help people and mountain lions coexist.

How could wildlife crossings help mountain lions?

Roads and development can isolate mountain lion populations, making it harder for them to find mates and maintain healthy genetic diversity. Wildlife crossings reconnect habitats, allowing animals to move safely across highways, reduce vehicle collisions, and strengthen populations over the long term.

Is there such a thing as a “balanced” ecosystem?

Nature is always changing. Wildfires, floods, droughts, species interactions, and climate all shape ecosystems over time. Rather than aspiring to freeze nature in place, conservationists work at maintaining the ecological processes and biodiversity that allow ecosystems to adapt and remain resilient. People have long been part of these landscapes as well. Indigenous communities stewarded California’s ecosystems for thousands of years, using practices such as cultural burning to sustain healthy, diverse landscapes.

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Mountain lions are only one thread in the Santa Cruz Mountains’ web of life, but they illustrate a larger truth: every species plays a role in shaping the landscape. Protecting biodiversity is about maintaining the countless relationships that allow forests, wildlife, and people to thrive together. By conserving connected habitats, we help preserve those relationships for generations to come.