Balancing Biodiversity: Managing Native, but Mostly Introduced Species

What do pink glowworms, blue oaks, and kangaroo rats have in common? They all reside at

Hastings Reserve, a UC Berkeley Reserve in Monterey county, California.

A female California pink glowworm, one of nature’s miracles, outside the office area at Hastings Reserve

Each of these species is one I have seen firsthand; a testament to the biodiversity that thrives in an area relatively shielded from anthropogenic influence. People rave about California’s biodiversity, and rightfully so. As the state with the highest number of animal and plant species in the United States, we do kind of know what we’re talking about with the whole biodiversity thing.

And yet, human influence is evident. Evident in the invasive grasses that blanket the rolling hills, and apparent in the overturned soil in areas where wild pigs forage. Even though humans did not do this directly, we are ultimately responsible for establishing these non-native species.

A view of the weather station at Hastings Reserve in early summer, with European annual grasses in the foreground

When I first began working at Hastings, I observed and scrutinized the oak woodland

landscape. I learned that many of the grasses that give California its “golden hills”, are actually introduced from Europe. This led me to ponder:

“What does a native Californian Oak Woodland look like?”

When I asked this to a well-known oak phenologist, he candidly responded:

“Nobody really knows.”

This question has proved to be the bane of my existence.

Not even indigenous people? Well, the sad truth is that they lost a significant amount of their generational knowledge due to European colonizers. But how can it be that everyone is okay with not knowing what our native landscapes look like?

I had this realization early on, but I was naive to think I could answer it during my time at

Hastings.

A quick evolution lesson:

Native species are evolved to thrive in the ecosystem they are native to. This could mean

having specialized protection against their predators, practicing mutualistic relationships with other species, and other adaptations which increases their fitness in their native ecosystem. So why is it that so many non native species outcompete their native counterparts?

It turns out that many of these introduced species are generalists, in the sense that they are

able to survive under many different conditions. These generalists often have little to no

predators in their introduced ecosystem, grow and reproduce quickly, and are more tolerant to disturbance. This results in introduced species outcompeting and displacing native organisms.

As for my experience with introduced species, here’s a short but comprehensive list on a few of the plant species that I have personally encountered.

Just writing this list brings mixed emotions; the plants by themselves are a handful. A large part of my job (and my supervisor’s) has been hand pulling these introduced plant

species. It is tiring work! It is also work that needs to be kept at; otherwise past efforts will likely have been in vain. Thankfully this past year, we were able to recruit help from several UC Berkeley students and a few visitor groups, to do what would have been impossible with our miniscule reserve team.

During my countless hours spent weeding, I began to ponder how these plants got to California, to a different continent for most. Unsurprisingly, there is often an intriguing story behind their journey, and it is often linked to an important historical event. Educating ourselves on their stories will help us learn from and not repeat old mistakes.

As for the first entity in the animal section, there is a new question in my brain.

A trail cam set up by Natalia captured this photo of Wild Pigs, (Sus scrofa), on a commonly used animal trail at Hastings Reserve

“Why is no one here studying wild pigs?”

As in, doing research on them. Learning about their moving patterns, life history, etcetera.

Hastings is a UC Reserve, after all. Meaning people travel from all over to do research on different flora and fauna. Sure, people want to study native species in their native range. But

aren’t non-natives just as important to study, if not, arguably more?

Wild pigs wreak havoc on endemic and vulnerable habitat, from aggressive rooting behavior

damaging agricultural areas and riparian ecosystems alike, to simply outcompeting many native omnivorous species for the food supply.

Don’t get me wrong– I have a lot of empathy for them. But they are having immense negative impacts on local flora and fauna, and their populations have only continued to grow.

Most people think of them as a nuisance, yet there has been no coordinated effort to eradicate them.

This will hopefully change in the coming years, but it will be a complicated process of

maneuvering public perception, trying different eradication methods, conducting research, and raising public awareness.

It is important to note that none of these species chose to be here, as I was reminded by a

fellow GrizzlyCorps friend.

They were almost always brought by humans who either didn’t know any better, or maybe just didn’t care. “Think 7 generations ahead” is what the Iroquois indigenous peoples would say, referencing that our actions today will ripple to our descendants far down the line. This simple but meaningful phrase can go a long way making people more eco conscious in their lives.

Star icon and local community member, Scott Hennessy, watering some freshly planted native wildflowers at Hastings Reserve

Even though I grew up as a nature lover in Southern California, I never really noticed how many introduced plant and animal species there were; I figured they all belonged.

Now I see them everywhere. And I hope you can begin to notice them too.