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Jeanette Lok is a senior majoring in Biology. Although she’s been drawing since she was a young age, she only started painting in the fall of 2010. Her TSR project explores the tensions between humans and mountain lions in the Bay area. Jeanette will join the Teacher Education Program at Harvard University this June.

Jeanette Lok

Fragments

Throughout the Bay Area, mountain lions are predators to smaller mammals, but they in turn also fall prey to humans who have urbanized the region. “Fragments” is an exploration of the tension nested within human-mountain lion interaction.

Puma concolor

Mountain lions (Puma concolor), also known as cougars, panthers, and pumas, inhabit a variety of terrains. They are limited more by the amount of prey available in their habitats than the humidity or elevation of the land; as solitary and territorial animals, they also prefer low population densities. The average male mountain lion stands 60 to 76 centimeters (2.0 to 2.5 feet) tall and is around 2.4 meters (8 feet) long from nose to tail, about 80 centimeters (32 inches) of which is the tail. Mountain lions are also the fourth largest cats, and weigh roughly 59 to 68 kilograms (130 to 150 pounds).

These felines prey on ungulates (1), and those found in the Santa Cruz Mountains feed mostly on deer and pigs. Mountain lions are the native apex predators of the San Francisco Bay Area, and historically these cats tend to avoid human contact (2). However, due to their large home range and due to urbanization and spread of people in the San Francisco Bay Area, humans and mountain lions have recently increased their levels of contact, creating conflict within this region.

Hesitation

With the recent influx in mountain lion sightings throughout the Bay Area, and with young children being raised in homes throughout the area, it indeed seems reasonable that twenty-first century industrialized Americans are scared of these felines roaming near mountain fringes. News articles document these cats in streets near schools and in the backyards of homes. Additional stories also describe a neighbor’s pet falling prey to these large mammals. Even at Stanford, the sighting of mountain lion tracks on the golf driving range enlisted a string of emails warning students and faculty to be alert. Very few Americans have received formal training on how to respond in the face of a mountain lion, and the byproduct of our ignorance mixed with our doubt that we will ever encounter one of these felines in our daily routines, is fear.

There is clear tension between humans and mountain lions. We are scared that they will harm us and our loved ones. The ironic reality however, is that humans cause more damage to mountain lions than the converse.

Fragmentation

Urbanization in the Bay Area has led to humans building homes and roads through the areas mountain lions currently live. As human encroachment expands and spreads throughout the region, mountain lion territory breaks into distinct pockets, a phenomenon called habitat fragmentation. This reduction of habitat size leads to crowding and increased competition between mountain lions, factors which warn of local extinction (3). Perhaps the most visible exhibit of mountain lion loss is found in collisions and road kills (4), seen as cars are speeding down the same motorways that mountain lions are trying to cross.

The innate necessity for mountain lions to inhabit a large home range dictates the need for larger plots of land than are currently available to them with urbanization; these roads and cities, which splice their territory into smaller pieces, are detrimental to mountain lion survival. In an effort to expand beyond what little the fragmented land has to offer, these felines will cross freeways and enter residential areas in search of prey and land. Although this is only a visible method contributing to increased extinction rates, genetic factors are also at play in determining the future of mountain lions in these fragmented habitats.

A further detriment of habitat fragmentation, though still debated, is the loss of genetic variation and reduction in gene flow (5) as mountain lions are confined to their smaller territories. The fragmentation of habitats greatly reduces the amount of land that mountain lions traverse, and consequently also the amount of mates the mountain lions can encounter. This limitation is the bottleneck of the mountain lion population. The lack of movement of mountain lions between habitat fragments leads to a reduction in gene flow between subpopulations because mountain lions will inbreed, and therefore existing genes and alleles will become even more dominant in future generations.

As the mountain lion population is forced through a bottleneck, the population will likely lose genetic variation, a factor which may also lead to low reproductive success, or low fitness. This loss of genetic diversity and decreased fitness is dangerous because it puts the mountain lion population in the San Francisco Bay Area at risk for genetic erosion, or extinction.

Anthropogenic infrastructures such as roads and buildings have contributed to mountain lion decline in the Bay Area. The fragmentation of habitats by way of urbanization attacks mountain lions from the physical perspective of vehicle-mountain lion collisions, and also potentially from the genetic perspective of decreased gene flow which consequently leads to decreased genetic diversity.

The loss of mountain lions in the Bay Area is essential not just for mountain lion counts, but also for the ecosystem at large. Because these cats are the apex predators of their territory, loss of mountain lions will indirectly affect successively lower trophic levels. As mountain lion populations decline, the populations of their prey will increase; in the Santa Cruz Mountains, this results in an increase in deer populations. Deer in turn feed on oak trees, and therefore the surge in deer populations results in a decline in oak populations. Oak regeneration is an identified issue within the Bay Area not only because the regeneration rates are slow, but also because oak trees provide a habitat and niche for smaller mammals such as squirrels, which consequently are decreasing (6) as a result of this trophic cascade.

While one pattern of mountain lion loss in a trophic cascade leads to a decline in squirrel population, another trophic cascade pattern can also result in the decreased numbers of song birds. Mountain lions are prey also to foxes and house cats, which consume birds. A decrease in mountain lion populations leads to increased amounts of foxes and house cats, which in turn decreases the bird population (7). The defaunation of mountain lions, the loss of this animal population, has detrimental effects that cascades down to other populations as well. As such, the mountain lion is also identified as a keystone species in the Bay Area, a population that influences both species richness of others and the flow of energy and materials through ecosystems.

CARNIVORE

Scientists who noticed the importance of mountain lion ecology in the Bay Area have formed the Bay Area Puma Project (BAPP), a research endeavor founded in 2008. It is a joint effort between the Felidae Conservation Fund, Chris Wilmers at UC Santa Cruz, and the California Department of Fish and Game. The research of the BAPP aims to track, capture, and tag mountain lions in the Santa Cruz Mountains to better understand the ecological role these felines play.

To research and properly monitor mountain lion movement, researchers have developed a GPS-accelerometer tracking system which locates the position of the mountain lion and also records the body’s motions. The GPS system is positioned on an expandable collar viable for use on both adults and mountain lion cubs. This system is also meant for use in terrains where connectivity may be intermittent, as is the case for pumas in the Santa Cruz Mountains. CARNIVORE (8) (Carnivore Adaptive Research Network in Varied Outdoor Remove Environments) is the sensor network system that relays information about the mountain lions to the researchers of BAPP. It is equipped to transmit signals and information from mobile-to-mobile nodes (when a collared mountain lion is within range of another collared mountain lion) and from mobile-to-static nodes (when a collared mountain lion is within range of a base station).

With data gathered from the collars, researchers identify where mountain lions are likely to feed and where they are likely to travel. The BAPP is currently tracking 15 mountain lions.

Oops

Due to the collared GPS-accelerometer tracking system developed by researchers from UC Santa Cruz, scientists have identified one particular portion of Highway 17, the freeway connecting Santa Cruz to the South Bay, where mountain lions are seen to traverse (9). To further prove the data of the GPS collars, one of the collared mountain lions was recently hit by cars near the location.

A dead mountain lion on the side of Highway 17 also drew attention from the public, as passersby noticed the mammal during their morning commute. Mountain lions have indeed fallen victim to the accidental and unjust interactions with humans, a feature they could not prevent.

Resolution

One solution to the defaunation of mountain lions due to habitat fragmentation is to reconnect the fragmented plots of land. Although this is in theory simple, it requires a lot of resources and research to verify the necessity for such a structure because after all, it is not feasible to destroy a functional highway or a prosperous city.

Researchers at UC Santa Cruz suggest the construction of a wildlife overpass, which may be the ideal form of connectivity, and is defined as “all bridge-like structures of whatever size, designed for use by fauna, or at the most, for dual use by farm vehicles and wildlife, and planted with grass, shrubs, or trees.” These overpasses currently exist in other places around the world, including France, the Netherlands, Sweden, Canada, and Florida, the first of which was built in 1974 (10).

In constructing an overpass however, it is important to also highlight the questions of functionality and opportunity costs: Will mountain lions use the overpass? And will the benefits that pumas receive from an overpass outweigh the costs of building one? Wildlife overpasses are one of the most expensive solutions to habitat fragmentation, and research identifies that open span bridges (underpasses) are statistically the most favorably used by wildlife (11). The frequency of usage is against overpasses perhaps because mountain lions are hesitant to climb into an unknown, which is facilitated by the arched design of an overpass. The arch obstructs the lion’s field of vision on to the other side of the overpass, and the mountain lion cannot assess the habitat on the other side of the terrain.

Nonetheless, research also suggests that wildlife overpass usage is correlated with regular inspection and maintenance. Although mountain lions found along the Trans-Canada highway transportation corridor prefer underpasses to overpasses, there is still merit to overpass usage because they are “less confining, quieter, maintain ambient conditions of rainfall, light and temperature, and can serve both as passageways for wildlife and intermediate habitat for small animals such as reptiles, amphibians and small animals” (12).

Taking the research from the GPS collars and the design of the overpass, researchers are exploring the construction of a wildlife overpass at the position on Highway 17 frequented by mountain lions. The projection of this new infrastructure works towards the benefit of mountain lion survival, and may counter the detrimental effects of habitat fragmentation. An overpass used by pumas will not only reduce the chances of vehicle-mountain lion collisions, but also reduce the likelihood of these felines entering residential neighborhoods in search of more prey and more land to inhabit. Although it has yet to be determined, the construction of an overpass may also facilitate gene flow between mountain lion subpopulations and also increase genetic diversity.

Reflection

In my search for a scientific advisor to mentor me in my initial vague topic of “ecology at Jasper Ridge,” I came across a lot of professors at Stanford who mentioned the prevalence of mountain lions in the Bay Area. However, none of these professors researched mountain lions beyond camera trappings, and my search led me to UC Santa Cruz. As the project progressed through the year, more news articles appeared about mountain lion sightings in our surrounding cities, and Stanford even reported cougar tracks on the side of campus in which I lived. I initially felt that this project would not be legitimate unless I saw a mountain lion myself, so I searched for them. I looked around the golf driving range at Stanford where the tracks were, and I even asked my roommate, a docent at Jasper Ridge, to take me for a hike around the Preserve in the hopes of encountering one. I never did.

Although I am disappointed because I did not see a mountain lion, it is no longer because I feel obligated to legitimize my project by my experiences with a mountain lion sighting. Instead, I wish I could see one in person because after hours of looking through mountain lion pictures (and still not being able to fully identify whether such and such a lion is a mountain lion, an African lion or even a bobcat), it would be a refreshing sight to see these felines in person. After finishing six paintings in colors a little more saturated and a little more exaggerated than real life, with the mountain lions a little smaller than their actual size, I want to have an impression of these cats beyond a painterly expressionistic view of these animals. I wish they were brought to life beyond the few highlights and brush strokes I can strategically place to add expressions to these cats.

In spite of my dissatisfaction that the subjects of my paintings never became more than just two dimensional research objects, I gleaned a lot from asking professors about mountain lions and reading journal articles regarding puma ecology both in the Bay Area and around the world.

The project as a whole was a learning experience in many regards. Although I could previously count on one hand the number of times I visited a professor at office hours to ask for help (because I did not want to be intrusive and simply did not know how to ask), I here found myself initiating appointments with professors I didn’t know and driving to Santa Cruz in the middle of the week to find photo sources for my paintings. I learned that beyond the wealth of knowledge found in research papers published by professors of these universities, there are also many ideas and insights that can be learned from speaking to a professor.

The process of painting was also in itself a learning experience, because I dabbled for the first time with oil paints at the beginning of the year. I noticed that as my paintings progressed, my style and my color palette choices also changed. Looking back at the original intent of creating unity in a series of paintings that varied in style and colors, my fluctuating brush strokes and preferences helped me to more easily achieve this concept. I was also able to experiment with materials I had never used before, such as gel medium, which I coated the news articles and journal articles with, and sharpies and watercolor pencils, which I never used on top of acrylic paints.

I began this project with two ideas: creation care and teaching. Over the course of this project, I have learned a little more about each of these two elements. In the field of creation care, I now understand a little more about why human perturbations are detrimental to the ecosystem around us—the anthropogenic infrastructures humans build can lead to a trophic cascade which affects everything between mountain lions and squirrels.

In the field of teaching, creating a project integrating both biology and art also pushes me to further explore the benefits of incorporating art into other core academic subjects in the context of secondary education. As an aspiring high school biology teacher, I am interested in how schools can, with proper scaffolding, incorporate an artistic component into their instruction to further facilitate a student’s learning.

Conclusion

The integration of mountain lion research with paintings will hopefully open avenues of communication between the general public and scientists. It is important for the public to be educated about human-mountain lion conflict—the causes, the effects, and the costs from both perspectives. Although mountain lions have trespassed onto human territory more so now than in previous years, humans should also recognize that our roads and cities encroached on their territory as well. Mountain lions are native apex predators, and one way to retain their presence in the Bay Area and to prevent local extinctions is the construction of a wildlife overpass. Data is still being collected and the BAPP is still researching and tracking mountain lions, and while this continues, we should educate ourselves on how we can contribute to the improvement of mountain lion ecology.

References:

1. Cindy Wilber (Education Coordinator, Jasper Ridge Biological Preserve), in discussion with the author, November 2010.

2. Bay Area Puma Project, Fact Sheet, http://bapp.org/.

3. Erika Zavaleta, Jae Pasari, Jonathan Moore, Daniel Hernandez, K. Blake Suttle, and Christopher C. Wilmers, “Ecosystem Responses to Community Disassembly,” Annals of the New York Academy of Sciences (2009): 311–333.

4. Sipke E. van Wieren and Pieter B. Worm, “The Use of a Motorway Wildlife Overpass by Large Mammals,” Netherlands Journal of Zoology 51 (2001): 97-105.

5. Luca Corlatti, Klaus Hackländer and Fredy Frey-Roos, “Ability of Wildlife Overpass to Provide Connectivity and Prevent Genetic Isolation,” Conservation Biology (2009): 1-9.

6. Rodolfo Dirzo (Professor, Stanford University), in discussion with the author, December 2010.

7. Christopher Wilmers (Assistant Professor, University of California Santa Cruz), in discussion with the author, November 2010.

8. Matthew Rutishauser, Vladislav Petkov, Jay Boice, Katia Obraczka, Patrick Mantey, Terrie M. Williams, and Christopher C. Wilmers, “CARNIVORE: A Disruption-Tolerant System for Studying Wildlife,” EURASIP Journal on Wireless Communications and Networking 2011 (2009).

9. Christopher Wilmers (Assistant Professor, University of California Santa Cruz), in discussion with the author, January 2011

10. Edgar A. van der Grift, “Defragmentation in the Netherlands: A Success Story?,” Schwerpunkt: Landschaftszerschneidung (2005): 144-147.

11. Claire C. Gloyne and Anthony P. Clevenger, “Cougar Puma concolor use of wildlife crossing structures on the Trans-Canada highway in Banff National Park, Alberta,” Wildlife Biology 7 (2001): 117-124.

12. Luca Corlatti, Klaus Hackländer and Fredy Frey-Roos, “Ability of Wildlife Overpass to Provide Connectivity and Prevent Genetic Isolation,” Conservation Biology (2009): 1-9 citing Jackson & Curtice 1998.