Life in thin air

At an altitude of 5.5 Kms above sea level the air pressure, and the amount of oxygen in every lungful of air you take in, is a little less than half of what you have at sea level. The amount of water available also decreases as you go up. The thin air and lack of water make for high deserts, until you get to the edge of the snow line. Here, where melt water is abundant in summer, life thrives. As we approached the high pass of Khardung La in Ladakh we entered such an altitudinal oasis.

Vegetation was sparse right at the top. But just a little way down was the village of Khardung, sitting on a stream that flowed from the meltwater around the pass. But even before we reached the village, we could see meadows where cattle were at a leisurely breakfast. I looked carefully at the black shapes: all were cows or dzos, crosses between cows and yak. Not a single one had the muscular shoulders of the yak.

Sitting quite apart from the cattle were a few donkeys. This was the first pack animal I’d seen in Ladakh. In many parts of the Himalayas and trans-Himalayas, motorized vehicles have replaced the mules and donkeys which were common a lifetime ago. But perhaps in these remote villages, where life can be snowbound for half the year, donkeys are still useful.

Right at the top of the pass I’d seen flocks of yellow-billed chough (Pyrrhocorax graculus, also called Alpine chough) doing the aerial acrobatics they are so fond of. The air was full of their deep musical tones. I looked carefully but saw none of their red-billed cousins. Both are creatures of heights; you won’t see them in Leh. On the chorten where the chough sits in the featured photo, I could see sprigs of juniper. There were no trees that I could see. Do people bring juniper branches with them when they cross? Lower down, just above the 4.8 Kms mark, we stopped for a chai. Flocks of pigeons wheeled in the air. Most were common pigeons (Columba livia), but I saw a few Hill pigeons (Columba rupestris). The one in the photo above was a lifer; the white band on the tail, and the white under the wing are characteristic of this species. Later I saw many more in Leh.

While we had chai there was time to look at the vegetation in this altitudinal oasis. There were stunted bushes of something that could be a tulsi or mint. The nearest bushes lay up-slope, and I wasn’t up to a climb to examine them closely. So I had to pass up the chance at a better identification and satisfied myself with the possibility that this belonged to family Lamiaceae. Of course, this is a large family, with over seven thousand species, but there cannot be many that grow so high up.

I’d been seeing bright orange patches on stone as we came down from the pass. They were to bright to be the mineral colours that we’d seen in rocks in this low-oxygen environment. Now that I could take a closer look, I found that it was the common orange lichen (Xanthoria parietina). This is a leafy lichen, a hybrid of fungi and algae. I find the symbiosis of different organisms making up lichens to be very interesting. For the first time on this trip I missed my dedicated camera for macros.

I’d thought that the green cover was entirely grass. I was not correct. There was grass, of course, but quite a bit of the green was due to a spreading succulent. I should have thought of that, deserts are usually full of succulents. It’s one way plants have of conserving water in a dry environment. Now that I know there’s such a variety of life at this altitude, I’ll have to stop and look carefully in future: perhaps I’ll even get to see the insects and small mammals which live up here.

Catmint in the sky

Scree covered slopes slid by outside the windows of the car as we came down from Khardung La. In the last few days I’d become better at spotting vegetation in this seemingly bare landscape. When I saw a tiny clump growing on a rock, I stopped the car and walked back to look at it more closely. The plant was new to me. In this thin air, at an altitude of about 5 Kms above sea level, I did not want to scramble up slope to smell the flowers and leaves. Instead I took photos.

A few days ago I would have been sceptical of tales of vegetation at these altitudes. But I’d been seeing too many birds at this height to dismiss the idea out of hand. There were corvids here, and they feed on small animals, lizards and rats, or large insects. Insects would need vegetation of some kind. Perhaps the smallest could live on lichens and moss, but anything which could feed a crow-sized bird would probably need plants. Still, it was strange to see a clump of vegetation on a single exposed rock.

A closer look revealed a shallow covering of soil in a little depression on the exposed face of the rock. The temperature was under 10 Celcius, perhaps around 7 Celcius, and the soil looked utterly dry and crumbly. I later found that the soil at this height, and in this season, holds less than 5% of its weight in moisture. This was a plant of a cold desert, adapted to extremely high ultraviolet light and extreme daily temperature fluctuations. I wondered whether its roots held on to cracks in the rock. With the wind here, it must be holding on to more than the thin soil. The roots apparently spread quickly to extend the area covered by the clump. But how did it get here? Did a seed drop here by chance, or did a bit of a twig with root blow into this island of soil? And was it wind that blew it here, or was it carried by a bird?

I’m not good with temperate or cold climate plants. It took me a while to figure that this could be a catmint. Perhaps if I’d smelled the leaves and flowers I might have come to mint (family Lamiaceae) earlier. From catmint it was a short search to find that this is Nepeta longibracteata, the long-bracted catmint found in Tajikistan, Afghanistan, Himalayan and trans-Himalayan India and Pakistan, and Xinjiang in China. The flowers grow from purple bracts, and have the trumpet shape and spots which seem to be characteristic of catmints. The perennial plant is apparently common across this region, although I saw it only this once. I found later that it yields an aromatic oil which is used locally. I’m sure I’ll not forget this plant if I come across it later: the leaves, bracts, and flowers are all very recognizable.

Don’t ask “What’s in a name?”

When I looked at the flowers that you can see in the featured photo, I was a little confused. I couldn’t remember seeing a dense inflorescence like this. Pink and purple buds emerged as showy blue flowers. Quite pretty. The bush was about waist-high. The serrated oval leaves were shiny after the rain. I was sure I would have remembered seeing them before. I was very surprised later when I realized that this could only be the bharangi (Rotheca serrata). The ones I saw before had shining white petals, except for the one that lay below the overhanging stamen. That one was was dark blue. This colour of the “landing petal” attracts pollinators looking for a drink. I looked at the photo carefully. Indeed there is a darker petal, properly positioned below the stamens. And yes, the range of colours recorded for this flower includes what I saw.

There is a long history of scientific mistakes and squabbles about its name. The blue fountain bush (aka the blue glory tree) was first named Rotheca serrata by Linnaeus. It has significant variation in form and colour, and has been misidentified and renamed over the centuries. For a biologist a name is more than a name. It is a means of placing a species within the history of evolution. And that has history has been retold several times. Current thought puts it in the mint/sage family, Lamiaceae. The genus name brings together only related plants. Genetic studies, published in the closing years of the previous centuries, confirmed this of Rotheca. The genus is found in tropical regions of Asia and sub-Saharan Africa. Field studies following this reclassification are still on. So the number of species in this genus is changing today.

Bharangi is widespread in India and Sri Lanka, and as far east as Malaysia. So, I was not surprised that its roots are used in several Ayurvedic formulations. They are used to treat coughs, fevers, and several related infections. There’s a fair bit of literature on extracting its active ingredients. That’s a field of work which pays off so well sometimes that pharma companies support it. So much human knowledge and activity behind that one flower! The Family asked me a simple question, “What is it?” That has such a long answer!