Yosemite’s “Good, Great & Awesome”

Society of Environmental Journalists' Morning Briefing

Speaker

Linda Mazzu

Chief of Resources Management & Science, Yosemite National Park

Sept 26 & 27, 2016 Yosemite National Park

Introductory Note

Before setting out to visit Yosemite National Park, a group of Society of Environmental Journalists gathered at breakfast to be briefed by Linda Mazzu.

Her morning briefing included a critical look at the role of water flows in determining critical restoration decisions. She addressed habitat needs and management of the park’s federally endangered species, including rare frogs, bears and bighorn sheep.

Outline

THE MERCED RIVER PLAN
AMPHIBIAN AUGMENTATION
YELLOWSTONE LAKES
BIGHORN SHEEP
CULTURAL ASPECTS of YOSEMITE
NATIVE HABITAT & TROPHIC CASCADES
SPECIES RECOVERY
PEOPLE & BEAR MANAGEMENT

Key Quote Water is what it’s all about! If you don’t have the water, you don’t have anything else. We’re also doing a huge amount of riverbank and meadow restoration in the valley. – Linda Mazzu

THE MERCED RIVER PLAN

LINDA MAZZU I call my topics to share with you tonight, “The Good, the Great, and the Awesome.” We’re in a quite a magical time right now when it comes to resources, protection, and conservation here in Yosemite National Park and outside of our boundaries. Additionally, we have a many great activities going on of which we’re very, very proud.

You have already been in the eastern part of the valley and along the meadow, so you probably heard about the prescribed burn there. Across the whole eastern part of the Yosemite Valley, we’re now implementing the Merced River Plan. I’m sure you’ve already seen some closed roads for traffic. We’re moving parking lots out of wetlands; and we’re creating roundabouts to reduce congestion.

We’re also doing a huge amount of riverbank and meadow restoration in the valley. Before the Ahwahnee Meadow was burned, we filled in ditches that were built there back in the 1920s and 1930s. There was a time in this park where meadows were a source of water, so they wanted to divert the water away for other uses. Thus, we filled in the ditches and moved an old road. Then we had the burn to improve that hydrological connectivity. [NB To read our NWNL Splash on meadow restoration, see Mountain Meadow Restoration.]

Water is what it’s all about! If you don’t have the water, you don’t have anything else. The same thing holds true regarding our Mariposa Grove Restoration that’s going on. It’s all about the water. We’re trying to bring water back to the resources. Whether it’s meadow restoration or whatnot, water is the key. The first thing we do is bring the physical resources back so we can ensure that our biological resources—our plants, animals and their habitats—will be able to survive what’s coming ahead due to climate change.

Given that challenge, we’re doing a lot of restoration. Just this week, we’re kicking off a riverbank restoration between the Ahwahnee and the Stoneman bridges. Many of those riverbanks have been trampled like crazy. Also, there are constructions here and there that have caused the riverbanks to become eroded; so we’re actively bringing back the riverbanks. We’re laying in engineered logjams and using designers to help us with some of the more sophisticated riverbank restoration plans. Right now, we’re just laying fallen trees parallel so that sediment will build up again. That helps establish needed habitats, which is important right now, because of all the species we’re now reintroducing into the park.

AMPHIBIAN AUGMENTATION

When it comes to our species, some are reintroduced. You could say we’re augmenting those populations…. We’re actively doing something about some of our rarest species. But first, we must make sure those habitats are going to be resistant and resilient to climate change. That’s our fundamental work right now. It’s a really big restoration program. We have just reintroduced the California red-legged frog that is a federally threatened species, and the western pond turtle which is under review right now. Those two species have not been seen in the park for about 50 years, so we are bringing them back. We also have Sierra Nevada yellow-legged frogs, so we’re doing a robust restoration for them. However, that’s at higher elevations.

I do want to talk a bit about the valley, since that’s our main focus right now – and I’ll keep discussing the amphibians. Back to the Sierra, the yellow-legged frog almost went extinct. That species was just on the verge when it got listed, and now its critical habitat is listed. Unfortunately, there are two things going against that frog: chytrid fungus, which is the global fungus that’s killing all amphibians; and then non-native fish that have been stocked in lakes in the park. They feed on the tadpoles and the frogs.

YELLOWSTONE LAKES

We’ve been restoring selected lakes in the park, but not all of them. We are dealing with those lakes where we think we have a good chance at having a strongly resilient habitat for these frogs – and where we’ve been able to remove the fish. So, it’ll probably end up being about 20 lakes out of maybe 1,000.

MALE JOURNALIST What does restoring the lake mean?

LINDA MAZZU First, we remove the non-native fish.

FEMALE JOURNALIST What are they?

LINDA MAZZU Mostly there were brown trout, brook trout or rainbow trout. Now there are rainbows in the river. Those are native down here.

MALE JOURNALIST How is removal done?

LINDA MAZZU We use gillnetting and some electric fishing, which is an important program. We’re happy to report that it’s working. We’re very concerned about these species, because we weren’t sure if they genetically could make it with the chytrid fungus.

But we found that when these frogs go through an infection of this fungus, some come out the other side still alive, and they are our hearty genetic species. They’re the ones we’re using to augment other lakes’ populations. I do want to mention some of our greatest partners: UC-Santa Barbara, UCLA and other universities working with us. We also have the San Francisco Zoo. They just opened the Yosemite National Park Conservation and Recovery Center which is taking and rearing our tadpoles and baby turtles for us, so they can bring them back. They’re also rearing the red-legged frog and the yellow-legged frog for Sequoia and Kings Canyon National Parks, as well. So that’s a great success story.

We’re doing the same meadow restoration – which I mentioned is going on down here – also at higher elevations. We have deeply-rutted horse trails though the meadow, so we’re moving those trails out of the meadow to bring back the surface flow of water – thus not disrupting the ground water for these meadows. That is important for the Yosemite toad, yet another rare species which is federally threatened. We don’t really have a handle on what actions we need to do for that species. All we know is they need breeding pools, – thus as much water as possible. That’s what we’re trying to do as we restore our high-elevation meadows.

BIGHORN SHEEP

I don’t want to forget to talk about the Sierra Nevada bighorn sheep! We have moved a herd of 13 sheep that we took from a herd down south. So, there are herds that are doing well along the Sierra. We have also established a new herd in the heart of Yosemite in the Cathedral Range where they used to exist long, long ago. We have two babies! It was a bit of a nail-biter over the winter, because the mothers and babies were staying very high – over 12,000 feet. It was snowing and blowing; but we got a picture of them. They made it, so that was extremely cool.

CULTURAL ASPECTS of YOSEMITE

The cultural resources are very rich here. We’re now having dinner in a National Parks landmark – The Majestic Hotel, also known as the Ahwahnee, built by Stephen Mather. This was his way of bringing people into the park. It’s always had a heavy stream of visitors; and it was a hospital for the military during World War II, I think.

This whole Yosemite Valley is a very interesting, unique area. This whole valley is a naturally and culturally created landscape. We work very closely with our traditionally associated tribes, because when they lived here, fire was an extremely important tool to them. They used to burn cliff-to-cliff. I wish we could do that again. It really helps with tree encroachment, and so we’re trying to help replicate that.

NATIVE HABITAT & TROPHIC CASCADES

The cool thing about Yosemite is its huge elevational gradient. It starts about 1,800 feet and goes to almost 13,000 feet. When you have that much elevation in your park, many different plant communities are represented, and with many plant communities, you have a great diversity of species. We know of about 1,500 species of vascular plant species in the park and around 80 or so mammals. Our developed areas are very busy, and very congested. We do have related wildlife issues; but all in all, if we can keep maintaining these resilient habitats, we should hopefully retain the park species’ diversity.

With climate change, we’re starting to see some biome shifting and some of the small mammals moving upslope. That has been documented, thanks to the Grinnell Survey that was started way back when. It has been a great way for us to see what’s happening with the foothills’ animal species, including the foothills’ chipmunk and ground squirrel, another small mammal. The foothill species are moving up. As far as trying to find a cool habitat, the alpine chipmunk is one of those species that’s going to hit the ceiling, just like the pika that we also have here.

The bighorn sheep that I have mentioned were just reintroduced into central Yosemite last year, 2015. But the frog work has been going on for about ten years or so.

We weren’t seeing progress at first, but I was able to visit a lake this year where I saw the whole food chain and all the trophic layers. You could see a frog, a toad, garter snakes and long-tailed weasels. The trophic cascade is working in places.

SPECIES RECOVERY

FEMALE JOURNALIST How well has recovery of these local species succeeded?

LINDA MAZZU I don’t know how old that recovery plan is. They wanted to do it for some time, but nobody thought things were quite ready. Remember, before you move an animal into a certain location, you must do habitat studies to determine whether there will be enough food and forage for them. We had to do that for about five-plus years.

Patrick Gonzales has a report that is kind of our Bible. He did a great job of summarizing how the temperatures will go up, and highest and worst-case scenarios, like 2,100 scenarios. It could be never-before-experienced degrees warmer, that sort of thing. That next step is species-by-species vulnerability assessments. They’ve done some work with recovery planning for these species. The things impacting the Valley are our higher-elevation head waters and large drainages.

Since 95% of this park is wilderness, we are taking a leap of faith that we are a refugia for these species. That is a huge leap of faith when it comes to this Valley, due to the amount of use in the Valley. But even though you see people everywhere, there are places where we can introduce species that don’t get visitation

FUNDING PARTNERSHIPS

Unfortunately, it all comes down to funding sometimes. Yet we do have great partnerships with Yosemite Conservancy and the State of California. I think overall success involves a little bit timing, a little bit funding, a little bit magic, and having all the right people in the room at the right time.

We are at a time when we do have to realize some species might not make it. That’s why we spend so much time researching whether the habitat is healthy or not. The thing about alpine vegetation and the alpine biome, that you must remember, is that there will be things moving up, perhaps not in the same combination or rhythm. But there’ll probably still be enough forage for these species to adapt. But if you ask me specifically about the alpine chipmunk, I would have to say that I don’t know.

Unfortunately, the research for a rare species rarely comes together most of the time.

FEMALE JOURNALIST How long has that program studying habitats been around?

LINDA MAZZU Not very long at all. They did the ribbon cutting for it in May.

PEOPLE and BEAR MANAGEMENT

LINDA MAZZU We’re at unprecedented levels when it comes to reduction in visitor management incidents. Never have we reached such a low number of incidents in the park. I think we only had 31 this year, while in the late 1990s we had 1,600 incidents, such as cars being broken in, etc. I think the statistics are at about a 95% reduction.. It’s a combination of providing storage lockers in all campgrounds, and now every division in the park has a Bear Council. The staff is all working together patrolling campgrounds, talking to people on the trails and in picnic areas, and making sure that people store their food correctly and don’t leave trash. It’s really people management. If you manage the people, then the bears will survive – and we’ve been doing a great job.

FEMALE JOURNALIST How do your bear-versus-people incidents compare to those in Yellowstone National Park?

LINDA MAZZU Grizzly bears have a very different behavior around humans and food. They tend to ignore people, but they also like to hang out near roadsides digging up the roots and whatnot. So, they draw crowds, which is a little bit different. Yes, we have “bear jams” here, but not nearly as much as Yellowstone. It’s a very different dynamic when grizzlies and black bears are together. You don’t really see bad black bear behavior. I won’t say it’s nonexistent, but it’s different.

MALE JOURNALIST What’s the approximate black bear population here?

LINDA MAZZU Between three to five hundred. I know that’s a big range, but unfortunately, we don’t get to study the population of black bears in the park. Most of our focus is on keeping humans and bears apart. We don’t have the capacity or money to go out and do a lot of population monitoring.

MALE JOURNALIST Thank you for sharing this information.

Posted by NWNL on August 10, 2025.
Transcription edited and condensed for clarity by Alison M. Jones.

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