Summer in Gothic has been hot and dry, paralleling warming trends seen globally.
Strong winds have been blowing dust onto every surface, and the biting flies remain.
For two weeks we had no rain at all. Until a few days ago, when the monsoon returned, bringing moisture from the Pacific Ocean, and clouds to the mountains.
Three days of rain, thunder, and the magical smell of wet soil were our prize.
The storms brought change to these landscapes. The soil surface rapidly saturated in many places, leading to sheet flow of water. And the subalpine firs (Abies lasiocarpa), many with dry or dead needles, shed most onto the forest floor.
For other species like this sunflower, the rain washed away a thick layer of dust, restoring photosynthetic rates.
And for others like this monument plant (Frasera speciosa), were partly blown down, but received much-needed moisture.
The rain has been good for rescuing some plants from drought-induced mortality. This silver lupine (Lupinus argenteus) ramet is now growing well in bare gravel saturated with moisture.
But for others, the rain has come too late. The yellow patch in this photo is a clone of Veratrum tenuipetalum, leaves dead and crisp from the dry period. Its apical meristems have died and it will not grow more this year, though next year will bring another chance to resprout from rooting stock.
I felt deadened by these two weeks of hot and dry conditions. But now the rain has returned, and with it, my joy for working here. There is more life and summer yet to come.
I spend a few days each week sitting in a meadow waiting for flies to bite me. Not by choice. The reason we are in the meadow is to measure plant thermoregulation with an infrared camera.
But the camera, once we set it up, requires very little attention. Every few hours we change the battery, and the rest of the time we sit there to make sure no one steals it or shoots it.
Sometimes we make other measurements, but otherwise there is very little to do but sit, and wait for the insects to come.
Some are friendly enough.
But others, like this snipe fly (Symphoromyia sp. [Rhagionidae]), are not. They swarm our bodies, sit on our datasheets, find our skin, then bite, and draw blood.
Every bite causes a painful swelling that lasts for hours and sometimes days.
They are surprisingly resistant to being crushed, often flying off after blows that would do in other insects. But they are slow, and most can be killed with a hand. Unfortunately, there seem to be an infinite population of them – no matter how many we kill, more kept coming.
I began wondering how many flies there really were. So I started a collection. Every time one landed on me, I tried to kill it. And then I put each of the victims into a plastic bag.
By the end of a 15-hour field day I had about a hundred dead flies in a bag. I estimate I was able to kill about a quarter of the ones I tried to hit, and probably ten landed on me for each one I aimed for. That corresponds to about 4000 flies. Far too many.
My fly collection was a small victory against the swelling and the itching, but it helped pass the time on these long days in the field. It made me wonder where all these flies went at night. I looked under all the nearby plants at sunrise and sunset, but didn’t find any flies. Some cursory searching suggests that very little is known about their life cycles – which is fascinating given how abundant they are for a few short weeks each year.
Not a research project I plan to pursue. I think it would be too painful. I’ll stick to collecting flies instead.
Summer is a risky season in the alpine. Plants can grow only in the limited time after the snow melts, and often die back as soon as the soil becomes too dry or the autumn snows begin again. The timing of snow melt is very unpredictable too. The amount of snow a mountain receives is important, but so too is the amount of dust that settles on it in late winter. This year at my site we had very little snow, but also very little dust. This photo was taken on June 18th by Jacob Heiling, and you can see my research site is still completely covered.
A week later we hiked up to the site to see how things were progressing. Most of the snow was finally gone, but meter-deep patches still remained on the landscape. As the snow contracts in late winter, it picks up gravel on its surface and produces some fascinating geometrical patterns.
The snow had also damaged my weather station, which I left to over-winter in place. A few of the sensor arms were crushed, either by the weight of the snowpack or through the action of the wind. But the datalogger and sensors were still functional, and I found out the snow only fully melted there on June 25th.
Despite most of the snow disappearing only a few days prior, the plants had already started growing, with a few Lupinus and Ivesia individuals sending up leaves. The growing season is precious time.
Now July has come, and we are back to begin intensive monitoring of these plants.
The snow has completely sublimed or melted at the site, and summer is here.
Last year at this point in July we found hundreds of Lupinus and Senecio seedlings in the permanent plots. But this year things don’t look so good.
Most of the lupines that grew last year failed to produce any above-ground growth, and nearly all of the seedlings are just dead. I counted only three seedlings on a quick walk through the site yesterday.
And many of the other species don’t look very good either – the leaves on this Phacelia are yellowing already. Mortality will be high this year, and I am looking forward to making a full census of the site in another week.
From a distance, the almost-bare slopes of this mountain seem not to change. But life comes and goes in the alpine. A year does make a difference.
How often do an industrial thermal camera and spectroradiometer end up in the hold of a Greyhound bus? The summer has come, and I am back in the Rockies for another summer field season focused on how alpine plant communities respond to climate change. Traveling with heavy research equipment is never easy, but after a full two-day journey by air, bus, and truck, everything is safe and ready for data collection.
The beauty of these mountains makes up for all of the challenges of the work. Every year that I arrive here, I am filled with a sense of joy and wonder for the place. There is still snow covering the high peaks, and the rivers are swollen with snowmelt. But while it may still be late winter up high, the valleys are full of life, with stands of green and white quaking aspen painting the landscape.
My work occurs primarily at high elevation, and one of the first things I did after arriving was go on a hike to scout out the snow line. My long-term research site is a few hundred meters above the snow in this photograph, so I’m lucky to have some extra time to get our equipment and protocols ready before the daily rigors of fieldwork truly begin.
This means getting all of the sensors up and running. I am using an industrial infrared camera to assess microclimate variation in plant communities. The camera can detect the blackbody radiation given off by warm and cold objects, and so determine the temperature of plants – something that may be highly important for growth and survival.
The main challenge is getting the camera in position to monitor the plants. With an international arrival by air I wasn’t able to travel with most of the equipment needed to do this, so the past few days have been filled with trips to hardware and lumber stores, building platforms that can support a heavy camera. But it all works now.
Here is one of the first images I took, with whiter colors corresponding to warmer plant temperatures. It is sharper and more beautiful than I imagined it was going to be, and it reveals a world of thermal ecology that was until now wholly hidden from me. In the coming days we will begin to learn much more about the lives of these plants, and the journey here will begin to yield its rewards.
Leaving for fieldwork in a few days – enjoy these videos of standing and traveling waves in a beachside stream. The dynamics look like they are controlled by thresholds reached during the buildup and transport of sand by water.
Never underestimate a squirrel. Growing up near the Atlantic coast of North America, I was familiar with the native eastern gray squirrel (Sciurus carolinensis) as a familiar feature of forest and urban environments. It seemed to coexist in both habitats well enough, and I never heard any stories of it causing ecological damage beyond the occasional occupation of a house.
A few weeks ago, I was on a tour of the Forest of Dean in England, led by managers from the government’s Forestry Commission. I knew the eastern gray squirrel was invasive in Europe, displacing the native red squirrel, but was surprised by the level of anger directed at this species by the land managers.
I learned that it causes dieback of many native species as well. Apparently it strips bark from trees like oak and beech. Because the bark conducts water and sugars to different parts of the trunk, bark loss can easily lead to the death of the whole tree. The downstream consequence is shifts in the dynamics of forest succession and the loss of trees that would otherwise be sold for timber. And there was evidence of these losses throughout the forest.
For a North American, this was an incredible surprise – to see a species shift so dramatically in its impact in what appeared to be very similar habitat. I don’t know what exactly causes this behavioral shift, and no one else among this group of ecologists seemed to either. Maybe they do actually strip bark in their native range but no one notices, or minds. Regardless, the land managers were certain about the damages caused by these squirrels and the need to control them, and equally surprised to hear that they caused no such problems in North America.
This experience made me reflect on the difficulty of predicting how species interactions will change in novel climates and biotic contexts. And it gave me a new respect for this species. The eastern gray squirrel is full of surprises.
Spring is yet to come in parts of Europe. I spent most of April in Norway working with collaborators in Trondheim, and was impressed by how much snow still remains in the mountains.
Lakes are still frozen, trees shrouded, and the high peaks buried under white cover. It is a very different landscape than the England I returned to.
But the snow isn’t everywhere. The variation in snowpack tells a fascinating story about where spring will come first. The first day of spring really comes on the date the ground becomes bare and life can return. And when the snow melts can vary by weeks even over a few meters of distance.
Wind can compact or drift the snow in some places, and blow it away from others. On ridge lines and mountaintops there are often complex patterns of bare ground brought on by these flows.
Darker surfaces absorb more heat, and melt snow faster. The dark tree bark of these trees has produced rings around each trunk, so that the ground will eventually open up near the trees sooner than away from them.
And landscapes’ orientation relative to the sun can lead to dramatic patterns of melt-out. This south-facing slope is bare and already supporting new growth while a meter of snow still sits on the north-facing slope of the same hill.
All of the ecology and growth of the organisms that need the summer warmth must follow these later-winter rhythms. When we look at a spring landscape, we are really seeing the history and the shadow of the snow that was once there. Winter does not end all at once, not anywhere.