A nickle placed on cryptobiotic soil shows how small the lichen is.

Small microorganisms called cyanobacteria, which are from the same family as blue-green algae, actually live on the surface of bare soil in the desert. For most of the Mojave Desert, the soil is usually characterized by rough dark patches as shown in the photo, but these cyanobacteria, with the aid of different types of lichens, mosses, and other colonies of microorganisms, can sometimes produce colorful soil crusts. In both cases, the soils are called cryptobiotic crust.

Lichen covers cryptobiotic soil in the Mojave Desert.

It takes a very long time for cryptobiotic soil to form, and it is also very sensitive to changes in its environment, so when it is disturbed, it does not have an easy time recovering. Some estimates indicate that it takes 250 years for damaged desert habitat to recover! When people use the desert for recreation, they have the opportunity to see and experience some of the most amazing scenery in the world. But if they are not careful, or they purposefully hike or drive off designated trails, cryptobiotic soil can be devastated.

When you step on cryptobiotic soil or drive over it, you kill millions of organisms that support the plant life that desert tortoises eat. If the soil is destroyed, then plants cannot grow, and tortoises will have nothing to eat. So if you know anyone who drives or hikes off trail and they tell you it’s okay because they are always careful not to run over tortoises or their burrows, you can now tell them it’s not okay because they are destroying cryptobiotic soils that allow plants to grow to feed the tortoises that they are being so careful to avoid!

As you can see, cryptobiotic soil is very important to the Mojave Desert ecosystem, and we should make every effort to avoid walking on or touching the soil. The next time you are out on a desert hike or driving down an old desert road, please stay on the designated routes to avoid harming the living soil below you.

Daniel Essary is a research associate at the San Diego Zoo’s Desert Tortoise Conservation Center in Las Vegas. Read his previous post, A Desert Tortoise Isn’t Just Any Old Tortoise.

Clouds and fog in the normally dry mountains near Cerro Venado.

Wow, what a difference a little rain makes in the dry forest! When I woke up this morning, I walked away from the base camp to look at the clouds and fog rolling through the valleys. It was just before dawn, and at first I thought it was still raining. Then I realized that what I thought were raindrops falling on me were actually flying ants!

A swarm of flying ants congregating and competing to mate after two days of rain.

As the light of the sun seeps through the dark clouds, I can see that the color of the landscape is changing. Instead of being brown, as it was only a day or two ago, it’s becoming bright green! There are thousands of tiny plants at my feet, each shorter than the width of my little finger. I have no idea what kind of plants these are, but it is impossible to walk anywhere without stepping on them. I knew that arid habitats often have an abundant number of seeds waiting in the soil for just a little moisture to trigger germination and growth, but it is one thing to “know” that something happens and another thing to see it right in front of your eyes. I can almost hear the plants growing…

Russ Van Horn is a senior researcher with the San Diego Zoo’s Institute for Conservation Research. We’ll be posting more about his trip every few days!

Javier and Robyn hike through the dry forest on their way to a waterhole.

Well, we have to be creative and persistent in our quest to collar Andean bears in the dry forest. The last few weeks have shown us that although we have learned more about the bears here than we have elsewhere, we still have a lot to learn!

After a few days of watching the small valleys where the sapote fruit is still plentiful, we’ve seen bears in the distance only twice. This is a much lower frequency of bear sightings than the Spectacled Bear Conservation (SBC) team gathered last year while the sapote was fruiting, but we don’t know why this is so. Jose walks through several valleys, scanning for evidence of recent sapote feeding by bears. He finds no fresh signs. Apparently the bears have shifted their movements back up into the hills, weeks earlier than they did last year, and the year before that. Variation between years in the behavior and ecology of wild animals is not unusual, and this is why it’s important to conduct long-term research. Knowing this is not very reassuring at the moment, however; it just feels like we’re having bad luck!

After returning from his walkabout, Jose checks the remote camera at another waterhole, and we learn that one bear or another has been visiting this other waterhole every four to five days. This sounds like a much more promising site than the sapote trees, so we shift operations and methods again. Every morning Javier and Robyn hike up to the waterhole and sit in a blind all day, waiting. The rest of us wait in radio contact at a distance, ready to hustle to the waterhole if a bear is darted.

Heavy fog and light rain obscure the rugged terrain of the study site.

Russ Van Horn is a senior researcher with the San Diego Zoo’s Institute for Conservation Research. We’ll be posting more about his trip every few days!

A DTCC staff member on a pickup service call

Last year, we received approximately 1,000 tortoises from the pickup service, and most were unwanted pets. We are anticipating that the number will increase this year as we reach out to educate the public about proper captive care for these special animals.

Angie takes a call on the hotline.

We are excited to start educating pet desert tortoise owners about captive care because we know this is a crucial step in ensuring the health of captive tortoises. A great majority of pet desert tortoises we received from the hotline last year were not healthy animals; interestingly, most had health issues that could have been prevented with small changes to nutrition and housing. With the San Diego Zoo operating the DTCC Pet Desert Tortoise Pickup Service, we will get the chance to talk to people face to face and address these issues. We also plan to offer a captive-care class at the DTCC. The topics we will be discussing include:

- Proper feeding and watering of pet desert tortoises
- Burrow construction
- Toxic plants in your yard
- Importance of desert tortoises living outside
- Brumation (hibernation)
- Sexing your desert tortoise
- Desert tortoises living with other domestic pets

We will also conduct health assessments on pet desert tortoises and be able to recommend tortoise veterinarians in the Las Vegas area. The class will be another way for us to get the word out about conservation of the desert tortoise. Our hope is that as the word spreads, we can begin to understand how many pet desert tortoises there are in the Las Vegas area, and we can make strides in decreasing that number.

We would like to coordinate with veterinarians and other local businesses to arrange for them to serve as authorized drop-off locations for the hotline around the Las Vegas Valley. These locations will help ease the demands on the pickup service staff, especially during our peak season from April to October. It will also provide pet desert tortoise owners anonymity when dropping off tortoises, so those who hesitate to call the hotline because they are required to provide an address and phone number may be more likely to turn in their pet desert tortoises.

We are looking forward to the New Year and new endeavors, and the new hotline will help us to spread our message of desert tortoise conservation all over southern Nevada and beyond!

IMPORTANT NOTE: It is against the law to remove a desert tortoise from the desert! If you come across one, even if it is a hatchling and seems helpless, it is healthier for the tortoise to stay in the wild than to be disturbed and brought to the DTCC. The wild desert tortoises that Clark County picks up only come from development sites and are removed by authorized biologists that are permitted by U.S. Fish and Wildlife Service.

The new Pet Desert Tortoise Hotline number is 702-488-9422.
The wild Desert Tortoise Hotline number is 702-593-9027.

Angie Sawyer is a research coordinator at the San Diego Zoo’s Desert Tortoise Conservation Center. Read her previous post, We Love Volunteers.

The team sets up camp on a ridge between two dry valleys.

The sky last night was clear, so the stars were bright overhead as we cooled off and settled into a new campsite. The moon was just past full, so we could easily have stayed up later, but we were all tired from hiking in the afternoon sun with full backpacks, and we went to sleep early.

We’ve moved to a different campsite because it was obvious that staying by that waterhole longer would not be an efficient way to immobilize and collar Andean bears here. Members of the team have seen bears coming down to feed on sapote fruits at lower elevations, so we’ve moved down, following the bears. This new campsite is also a dry camp and is more exposed to the sun, but visibility is much better than higher up, next to the waterhole.

The dry valley at the field site.

As time passes, there are numerous demands for my attention, but I can’t allow myself to be distracted. If a bear were to come down from the mountains into the valley, it might only be visible for a few seconds, so I can’t stop watching. Gnats appear and start flying into my eyes and ears and bite my face, hands, and wrists. Pairs of birds that I suspect are probably flycatchers, fly across in front of me and perch in a shrub only 20 meters away. This area is known for being home to a high number of birds that live nowhere else, so it’s tempting to watch these birds through my binoculars for just a little bit, but I force myself to keep my mind, and eyes, on guard for bears. A large vulture, probably a king vulture, soars into my peripheral vision and then crosses back and forth over the valley. It would be so easy to get a good look…but I’d rather get a good look at a bear!

A sapote tree in a dry valley at the field site.

At 10:30 a.m., I see Robyn briefly as she changes position. At 11:27 a.m., everyone returns to camp. The field team doesn’t expect bears to be feeding in these valleys at mid-day, so we’re taking a break for lunch and to rest. It’s harder than you might think to keep alert for hours in the sun! Other than the bear sighting, the most interesting topic of conversation is Jose’s temporary friend. As he was sitting watch, he felt something on his back, underneath his shirt. This is nothing unusual, as there are a lot of gnats, and ants crawling on all of us. What was unusual was that this visitor seemed to be longer than an ant could be. Jose realized what it was and made the wise decision to not swat at his “guest,” which was a large centipede. The centipede, about 10 inches long, walked up his back, across his left shoulder, and down his left arm, exiting his shirtsleeve and going on its way.

We’re all back in place by 2:30 p.m., except for Jose. He’s hiked up into the hills to replace the memory cards at some remote cameras. We’ll look at those photos later and decide whether or not to stake out a different location. At 4 p.m., the breeze dies, and the gnats return. Fortunately, at 4:15 p.m. a swarm of golden dragonflies follows the gnats. Jose and the others return to camp at 4:40 p.m.. A bear, possibly the same bear as seen this morning, crossed back over into the upper part of the other valley at around 3:30 p.m. but it kept walking up into the hills, away from where we waited.

A fox is caught by a camera trap at a waterhole at the study site.

Russ Van Horn is a senior researcher with the San Diego Zoo’s Institute for Conservation Research. We’ll be posting more about his trip every few days!

A physical examination of wild Andean bear named Chris.

I’m sometimes jealous of people who can describe how things smell, or taste. I know the same words that they do, but they truly understand how to use the words. If I could, I would describe for you what a wild Andean bear smells like. Instead, all I can say is that “Chris” smelled like a bear.

I’ve been familiar with the general smell of “bear” since I was a child, growing up in black bear country. Since then, I’ve been fortunate enough to smell black bears and brown bears across the mid-western and western United States, but this is the first time I’ve ever sniffed a wild Andean bear. Yep, Chris definitely smells like a bear!

GPS satellite radio collar, ready to be placed on Chris.

A GPS radio collar is properly fitted to Chris’ neck.

When he was darted last year, Chris had large blisters, or sores, on the pads of his feet. Robyn Appleton and her team can only guess that he’d worn down his footpads walking long distances on the rocky trails of the dry forest. This year, his feet are in good condition, which leads us to more questions: why were his feet more worn last year than this year; did he walk more last year than this year? If so, is this because he dispersed from his natal home range last year? Dispersal is the term for the process by which an animal relocates from one living place to another. A natal home range is the area where an animal was born. In most species of mammals, males disperse from their natal home range to a new area at around the time they go through puberty. In a few species of mammals, it is females that disperse, not males. The currently available evidence suggests that female giant pandas disperse but male giant pandas do not; male brown bears and American black bears disperse, but females of these species do not. No one has collected much evidence on whether it is male Andean bears or female Andean bears that disperse, but the probability is that males are the dispersing sex in this species. Were Chris’ blistered feet a clue as to whether male or female Andean bears disperse? Only time, and additional data collection, will answer that question.

We have additional questions on our agenda. We’ve seen and heard several bears in the area exhibiting behaviors that lead us to ask, is this the breeding season for Andean bears in the dry forest? If so, has Chris sired cubs? What determines whether one male sires cubs and another male does not? We can generate hypotheses to address these questions, but it will take a lot more work and data to test the predictions of these hypotheses and reach conclusions about the answers to our questions.

After we finished our physical examination of Chris, we moved him to a comfortable, safe place to recover. The last we saw of him, he climbed up a 10-foot-tall (3 meters) rock face and slowly walks uphill, out of sight into the dry forest. Forty-eight hours later, according to data transmitted by his new GPS collar, he’s 2.72 miles (4.38 kilometers) away, in an area with plenty of sapote trees, which produce fruits that bears in this area often eat. We, on the other hand, have moved less than 100 yards (91 meters), because we’re continuing to try to collar more dry forest bears. I wonder if the next one will smell like Chris?

Russ Van Horn is a senior researcher with the San Diego Zoo’s Institute for Conservation Research. We’ll be posting more about his trip every few days!

There are serious logistical constraints involved in Andean bear fieldwork, whether in the cloud forests of Cusco or the dry forests of Lambayeque. In the dry forest, the critical constraint for we humans is water. For those of us waiting to collar bears, it’s WATER, in jugs of 20 liters (5.28 gallons), carried in backpacks from the flat lowlands into the rugged hills.

Although we’re camped near a waterhole, we don’t actually have access to any of the water in it; that water is for the wildlife to use. Based on what they’ve observed, Robyn and her team from the Spectacled Bear Conservation Society (SBCS) believe that bears travel down trails higher on the canyon walls to feed on sapote fruits at lower elevations, and return up this canyon to drink and swim in the waterhole.

Even though there is little drinking water in this area for wildlife, the bears may go for days without drinking, based on data from GPS satellite collars on some of the bears and photos from camera traps. Where do the bears get moisture when they’re not visiting waterholes? Robyn’s hypothesis is that they obtain some moisture from the sapote fruit and from eating cactus. One of our research goals here is to understand the ecology of water in this habitat, and one of our conservation goals is to promote protection of the watershed and the waterholes.

Just after dawn in Lambayeque, Peru.

Just before sunset in Lambayeque.

We talk in whispers about what veterinary actions to take under different circumstances, how to proceed with research, how to raise funds for research, local politics, and what cold beverage we each crave. I’m yearning for a strong ginger ale I first drank in Kenya, while working on my doctoral research. I’ve never found this beverage for sale in the United States, but it would taste great right now, almost as good as a swallow of clean, pure water. We’ve used 20 liters of water in the days since the last jug of water was carried up to our campsite, even though we’ve used as little water as possible. The water jug is now dry, but with luck we now have to wait only four or five more hours before the hikers arrive with another full jug.
Tick.
Tock.

Russ Van Horn is a senior researcher with the San Diego Zoo’s Institute for Conservation Research. We’ll be posting more about his trip every few days!

My Zoo work hat after a few days in the dry forest.

The goal of my trip to the dry forest of northern Peru is to work with Robyn and SBC’s team to capture several Andean (also called spectacled) bears, and fit them with satellite GPS collars. Dr. Meg Sutherland-Smith, a veterinarian with the San Diego Zoo, will provide top-notch veterinarian care for any bears we immobilize during her stay and give Robyn and I additional training and advice in these procedures (see Meg’s post, Peru: Room with a View). The data we obtain from these collars will give us insight into the amount of space that bears need in this tropical dry forest, which is a threatened habitat.

The flight from San Diego to Atlanta was just long enough for me to compose some long-overdue e-mails, and my time in the airport allowed me to send them off. Luckily, I still had the eight-hour flight from Atlanta to Lima during which I could finish some writing tasks that were due while I’d be in the field. One of the minor, yet critical, challenges of leaving for the field is that I have to think ahead of all the deadlines that will arise while I’m offline for a few weeks, or months: deadlines for progress reports, funding proposals, abstracts for conferences, etc.

In Lima, I had a quick and easy trip through the customs checkpoint, and then I carted my bags upstairs to a coffee shop with wireless Internet access for a few more hours of work before catching my flight to northern Peru. I boarded the flight for Chiclayo as the sun brightened the cloudy sky and immediately fell asleep, for the first time in over 24 hours. The flight was smooth, and I didn’t dream of the tasks behind me, or those ahead of me.

My good luck continued to hold. As I walked out of the Chiclayo airport, it was obvious which person was there to meet me. Not only was he the only person not wearing the badge of a licensed taxi driver, he also held up a sign reading osos, which means bears in Spanish. He’d been sent to start me on my ground trip from Chiclayo to Cerro Venado, where I’d spend most of the next 24 days.

A short taxi ride took us to the ground transportation terminal, where it is possible to take a bus to the local villages or hire a taxi for the trip. We couldn’t afford to wait for the bus, so we joined several others in a cab ride to the village of Batan Grande, passing by green fields of sugar cane below low, dry mountains. At Batan Grande, we stopped to drop off some of my excess gear, including a set of clean clothes for the flight back to Lima. Javier Vallejos leads SBC’s field team, and his wife, Pepa, renewed my sagging soul with coffee and breakfast while their young son watched a DVD on the wildlife of Manu National Park (see Cocha Cashu: Wild Nature).

Mototaxi loaded with Russ' gear.

The fence and gate constructed by the local cattle owner’s association, with help from SBC.

Two young men were waiting in the shade of a shrub for me to arrive. Wow, my trip required a lot of coordination by Robyn and her team! Isai Sanchez and Jonathan Vallejos helped me carry my gear up to the nearby base camp, where we reorganized it into backpacks. It was the hottest part of the day in an area where temperatures reach over 104 degrees Fahrenheit (40 degrees Celsius), so we napped in the shade until it cooled off a little. We hiked along the foothills until we reached another campsite, where we met another member of the SBC team, Jose Vallejos.

After a quick meal, we grabbed our backpacks and set off uphill, heading toward a campsite where the others waited near a waterhole. With luck, we’d be collaring bears that approached this waterhole.

Nearly ripe sapote fruit

Russ Van Horn is a senior researcher with the San Diego Zoo’s Institute for Conservation Research. We’ll be posting more about his trip every few days! Read Russ’ previous post, Andean Bears: Camera Trappers.

I am in the middle of another of my many field trips, on the way to St. Bees Island via Clermont in central Queensland, where I am assisting my colleague, Dr. Sean FitzGibbon, at his research sites. Sean is also using GPS tracking collars on koalas (as we do at St. Bees), but he is investigating whether koalas will use rehabilitated land. His research takes us onto disturbed land that has been mined for coal in central Queensland and where the land has been replanted with koala food trees to recreate koala habitat.

In the past, we have found that some male koalas have made forays into the rehabilitated areas, probably looking for new food areas or maybe searching for mates. When we download the GPS data from the collars, we can tell where the koalas have been and for how long they have used areas in their range. On this trip we have found something extraordinary: a female we caught and collared last year well away from the rehabilitated sites has moved into the new habitat and spent the summer producing a joey whilst living on rehabilitated land!

In the photo you can see this koala, named Hillary, and the coal mine’s environment officer, Clare Foley, who is in charge of developing the reconstructed areas of the mine once the coal has been removed. The rehabilitation where Hillary lives was replanted in 1996, and you can see that many of the trees are still quite small, and there is plenty of long grass as a result of recent rain. While walking through this land we found many other animals—particularly frogs, kangaroos and lizards—that have re-colonized the once-cleared areas.

This tells us that not only is the recreation of koala habitat possible, but that by doing this we will recreate habitat for a range of other species. Finding koalas living in revegetated land means that in other places, like Southeast Queensland, we could be planting more trees and turning cleared land back to what it once was: habitat for many native species. It can be done, so in the long term we can increase, not decrease, the land available and suitable for koalas.

We are off to St. Bees Island now, a special place if for no other reason than that it is protected from any development, so the koalas can exist without the fear of habitat loss. It has its own management problems, but they are a far cry from trying to recreate homes for koalas amongst cleared bush in central Queensland.

Bill Ellis is a Clark-endowed Conservation Research Postdoctoral Fellow for the San Diego Zoo’s Institute for Conservation Research. Read his previous post, Urban Koalas.

Bai Yun watches Yun Zi's antics.

When she first arrived at the San Diego Zoo in 1996, Bai Yun was a young adult bear. She had an annual estrus the first three years, until daughter Hua Mei was born. During that time, we would see an increase in scent marking about two weeks prior to ovulation, and an increased restlessness would set in. Why might a female undergo such changes so far out from her breeding window?

Recall that in the wild, pandas maintain overlapping home ranges. In those home areas, the bears are generally solitary as adults. However, they are exposed to the scents of other neighboring bears that have crossed over their path days or weeks before. If a female is a few weeks out from peak receptivity, it makes sense that she would need to begin to advertise her status to any males that might be in the area. She scent marks, and a male who comes across her scent a few days later can recognize the change in her status via that scent mark. Our research in Wolong has confirmed that males are more interested in scent from a female who was known to be in estrus at the time she left the scent. Once he has identified this change in a female’s status, a male will then likely remain closer to this female, assessing her status more frequently and keeping closer tabs on her in order to be present at the time for mating.

A younger Bai Yun has demonstrated that about a week prior to her peak, her rate of bleating begins to climb. This friendly, goat-like vocalization picks up at a time when males in the area are likely to be closer than usual, thanks to her increased scent marking. Within a few days of her peak, she increases her rate of chirping, a sharp, louder vocalization that we can often hear through the doors and windows of our building! Recent research from our collaboration with Zoo Atlanta has revealed some interesting information about these vocalizations and how they relate to male-female interactions: it appears males can use elements in the chirp to identify the precise time when a female is most fertile. Thus, when a male that has been hanging around waiting for his opportunity to mate hears his female chirping, he can assess whether or not she is ready to breed yet.

I have often wondered about Gao Gao’s ability to assess Bai Yun’s readiness for mating. Even with a truncated estrus in the last few years, and limited exposure to her scent, he seems able to pinpoint the time to breed with her. The next day, despite her willingness to breed again, he may often show no interest. Perhaps it is a change in the sound of her chirp that he is assessing and determining that it is not worth his effort to endure another breeding encounter. For a wild male, following a female closely can be an energetically costly endeavor: he risks coming into close contact with other males, and fighting may result. The process of mating itself is laborious and may take up most of a day or two, leaving him physically drained. If a female turns on the male during courtship, he could be injured. And all the effort in assessing and breeding with her detracts from his feeding schedule. Thus, it would seem that making judicious choices about when to push his luck could be advantageous to a male panda.

Why am I discussing this now, when Bai Yun is sure to experience a lull in her estrus cycle due to the fact that she is still nursing Yun Zi? Because, despite Yun Zi, we have an estrus in progress in San Diego: this time, with Su Lin. Unlike her little estrus last year, our young bear (four years old) appears to be experiencing a more adult-like, full-on estrus. She is deep into the scent-marking stage, complete with restlessness. Bleating has begun, and chirping should be on the horizon soon. This is likely her first fully fertile estrus, as females in Wolong have been bred at her age, resulting in a birth a few months later. However, Su Lin will not be breeding here, since she clearly cannot breed with her father Gao Gao. Nonetheless, this is an opportunity for the public to observe a full, lengthy behavioral estrus in a panda female, something we haven’t seen around this facility in many years!

Suzanne Hall is a senior research technician for the San Diego Zoo’s Institute for Conservation Research.

Here’s the most recent chart comparing our panda cubs’ growth during their first 200 days: