Walking around a village

We drove a few hours from Kochi to Thattekad, and reached a home stay on the far side of the Periyar river. In the evening we crossed the river for a walk around Thattekad village. From the highway it looked like there was only a rain-forest nearby. Then I saw the little path worn away by regular use. As we followed the path, I realized that this was not a pristine rain-forest; it had been cleared for human use.

The word ecosystem comes to mind as you walk around the village. The network of species is not as dense as it would be inside the protected forest, but you can see it here very easily.

A speckled piculet pecked away at a bare tree: there were clearly insects running up the trunk. I’d never seen a piculet before.

Ants swarmed over tiny yellow flowers which I didn’t recognize. They pollinate the flowers even as they harvest nectar. Elsewhere, a deeper food chain: aphid colonies have taken over a patch of bushes, and ants run up and down them, clipping their wings and harvesting the honey dew which they secrete.

There were flowers which I did not recognize. The one thing which I did was the touch-me-not, familiar from my childhood. Its leaves curl up if you touch them. This was the plant whose name, Mimosa pudica, first introduced me to Latin binomials.

Above us a plum-headed parakeet hung upside down, feeding on tiny fruits. Parakeets disperse seeds widely, and are key players in keeping a forest alive.

As soon as you get away from a city you begin to see the web of life which covers our planet.


Flowers and birds of Munnar

The accessible part of Eravikulam National Park is a disappointment at first sight. It is a narrow sliver of protected land between plantations. A black-topped right of way cuts through it. If you look at everything on the way carefully, it might take you an hour to walk up the road, and another hour to walk back. In spite of this, it is a jewel of conservation. The number of birds and plants you see on this walk is immense. It is only when you see this variety that you realize that the park spreads far, and tourists are allowed only into this little stretch. As usual, what I managed to photograph is a small part of what I saw.

The walk is up the flanks of the “Elephant” whose head is Anamudi. Rising to 2695 meters, this is the tallest peak in India outside the Himalayas. I did not look for the famous butterflies or amphibians of this region. Nor did I look at the insects which must be ubiquitous, given the number of insectivorous birds that we saw.

The greening of a rock

At a place called Urulanthanni near Thattekad is a rock poking out of the surrounding rain forest. The area is a ecological hot spot. The dense canopy of the forest holds a very large variety of endemic birds, which are invisible from the ground. The rock provides a great vantage point from which to view the activity in the canopy. In fact, as you can see in the featured photo, the canopy itself is a grand view.

While walking in the forest I’d noticed basaltic rocks poking out of the ground at various places. So the whole rain forest here has been formed by sedimentation and erosion of the volcanic rock. This knoll that I stood on was a rougher rock. On the surface I could see a flowing texture created by weathering. You can see this in the photo below. But when I looked at a broken face in the rock, as in the photo above, I could see the grainy texture of the rock. It seems that the rock here is a mixture of two kinds called gabbro and syenite. Both have this texture, but are different in the minerals that they contain. So this giant rock must have been created by a separate upwelling of magma within the volcanic rocks underlying the land around us. The red insect is the nymph of a bug which I saw later.

How did inhospitable rock become the bed of a rain forest? Observations on Mount Saint Helens has given us a wonderful insight into how biology covers geology. Could I see the beginnings of the cycle on this dome? Almost certainly the bare rock was covered by bacteria. But the smallest things I could see were mosses. I regretted not bringing my macro attachment. I would have got wonderful photos here. At the next level of organization, I could see soil blown into little hollows in the rock, as in the photo above. Was this enough to support plants?

It seemed that it was. I could see clumps of bushes growing in these thin mats of soil. As they grow and shed leaves they add to the soil. They also present a barrier to winds which cause the air to drop soil around them. Right at the exposed top, the process of bootstrapping the creation of soil is slow. But just behind the flat top, it proceeds faster, accelerating even more as you go down the slope. In the photo above you can see the scant bushes at the flat top growing in a thin mat of soil, and the larger thickets of bush lower down. You can also see a few trees which have taken root in the upper slopes. Eventually, the bacteria, moss, bushes and trees will erode the stone into soil, and this dome will be covered in vegetation!

Once there was a river

In the 9th century CE the Adi Shankaracharya crossed the Narmada river and met his guru. The foundations of modern Hindu philosophy can be traced back to that event. I decided to make a quick dash to this immensely historical place in early January, and drove across the Narmada. The experience is totally disjoint with the classic sanskrit poetry that one grew up with. As the car swept over the bridge, my mind played back the lines Maha gabhira niira puraa paapa dhutam bhootalam (Your deep waters which overflow the banks and wash away the sins of the earth). Those waters have been reduced to a thin stream.

Through the 1990s a protest movement against damming this river in the west was perpetually in the headlines. Now, crossing a bridge between Omkareshwar and Maheshwar, far to the east, I saw how limited was the scope of those unsuccessful protestors. Upstream barrages are much more destructive of ecology than dams downstream, since they affect longer stretches of the river. The Narmada is one of the main westward flowing rivers of India, but almost nothing about the barrage upstream of Omkareshwar, entered the public discourse.

I was not surprised when I read that this tells on the fish population in the river. The mahaseer and the hilsa which the Narmada was known for, even a generation ago, has been replaced by imported catfish and carp. The trickle of water below the imposing bridge is a reminder of the lost connection with history. Have people gained or lost? Talking to farmers around here, one has the feeling that the water diverted to irrigation has been a gain. But if you talk to fishermen, you hear a different story. If these problems were not complex, we would have solved them by now.

The sea of the ship of the desert

I saw this stretch of sand and did a double take. The pattern of light on it made it look like the bottom of a shallow sea It was not hard to imagine that the light refracted through ripples in water could make the caustics and dark patches that I saw. But the patterns were static. Things had walked across the desert, and then the wind has worked over their tracks to make the gentle ripples in the sand that you see in the featured photo. I looked around to check whether I could recognize from a new spoor what had made these patterns. The obvious guess was right: they were the footprints of camels.

Looking up from the sand it was clear what attracted the camels here: the acacia trees which were all around me. The Acacia jacquemontii is a common second wave of growth over sandy areas which have been stabilized by plants such as the khimp and phog. While writing this now, I had a moment of doubt about the identification. Was it really the local babool tree, A. jacquemontii? The shape of the canopy looked like that of the babool. But still, could it be the imported Israeli babool, Acacia tortilis, which the state government is partial to, since it grows faster? I looked at a photo I had taken of the leaves, and found that it was indeed the native babool.

Camels’ delight!

The desert of full of spiny leafless green bushes. Leaves present a large surface to the sun and are great organs for photosynthesis, but they also lose a lot of water through transpiration. Green stalks can carry on photosynthesis while minimizing water loss. Of course, they also present a smaller surface to the sun. So this is a thorny problem (yes, I meant that) which plants have to solve: more photosynthesis or less water loss?

The local name for the green bush full of upright stalks which you can see in the photo above is khimp. The plant grows along the extreme arid zone which crosses from Mauritania to India through the Sahel, the Arabian desert and the Thar desert. A search for the origin of the botanical name Leptadenia pyrotechnica led me to this book, which claims that the name pyrotechnical comes from the observation that Bedouins use tinder to set alight the fibrous stems of this plant. Later compilations noted that the high fiber content of the stems has been used by people across its geographical range in various ways. Some have used it to make ropes, others in diet to cure anything from constipation to obesity. Although I never thought of breaking off a stem to look at the sap, I’m told that it gives a clear sap. This is probably one of the reasons why camels are said to be fond of it.

There is a claim that extracts from plant was found to be mildly damaging to liver cells in a lab. On the other hand it is said to be eaten. Browsing the net, I came across a recipe for cooking khimp. Here is a translation: “Cut the stems and boil them. Remove them from water and press to drain the liquid. Separately cook spices in oil and add the boiled stems. Add a little buttermilk to cook further, thickening it with besan (chickpea flour) as needed.” The double cooking of the stems probably serves not only to tenderize the material, but also to denature toxins. The pressing and draining may also remove any toxins.

They grow along with phog on dunes and other dry sandy places. In various countries around the world people are experimenting with using L. pyrotechnica as a biological barrier to the spreading of dunes. But when I stood on top some dunes and took the photo above, I did not know that this could also be a weapon against cancer.

Vulnerable Vultures

The literal meaning of the word “pastoral” is the keeping and herding of sheep and other livestock. The metaphoric meaning extends to farming and country life. If you think only of the metaphoric meaning, then you will never describe the Thar desert as pastoral. However, when you give up metaphors and look at the real meaning of the word, then “pastoral” is the word you will use to describe the livelihood of people in this desert. Scenes like the one in the featured photo are common.

Also common, and becoming more so, are sights as in the photo above. You often find bleached bones of sheep gleaming in the dusty brown landscape. Carcases are sometimes left to lie where the sheep died, as the nomadic pastors move on, so one can get a whiff of a dead animal while driving across the desert. There are also municipal and village dumping grounds for carcases. A variety of scavengers pick the bones clean. Among them the ones I found most interesting are the vultures. In the Rajasthan desert seven of the species of vultures seen in India have been recorded. We managed to see a fair fraction of them.

The sighting to remember was of this red-headed vulture (Sarcogyos calvus) feeding. Historical reports of this species show that it was infrequent but widespread throughout southern and south-east Asia, including the southern parts of China. Habitat loss and change in methods of disposing of carcases of livestock has pushed it to local extinction over large parts of south-east Asia, with only a small population left in Cambodia and in eastern Myanmar. The largest pool is in India, Pakistan and Nepal. Even in this heartland, its numbers fell dramatically in a few years around the beginning of the 21st century. The cause of this decline was traced to the use of diclofenac in treating inflammation in livestock. It turns out that this chemical is fatal to vultures. With the ban on veterinary use of diclofenac and its replacement by other compounds, the population has begun to grow again. However, the IUCN red list still lists it as critically endangered. I might have seen it in 2005, but I have no record of it. So this could well have been a lifer for me.

One thing that strikes you immediately when you see the Egyptian vulture (Neophron percnopterus) is that it has a short and feather-covered neck. It is an opportunistic feeder, picking at the remains of a carcass after other vulture species have left, and eating small animals, insects, fecal matter, as well as eggs. It is among the very few tool using birds, using rocks to smash eggs. It used to be widespread over Europe, the Sahel and Arab desert, and India. In three generations of the bird (about sixty years) the European population crashed to about a half of what it was in 1960. Poisoning of animal carcases against predators first hit the European population. Then EU regulations on the disposal of carcases, implemented in the early years of the 21st century, hastened this decline. In India, the rapid die-off of other vultures increased the exposure of this species to diclofenac, so leading to a cascading decline in numbers. We saw a few of these birds in the two days we spent in the deep desert, so the Indian numbers have presumably stabilized. IUCN has revised its assessment of this species to vulnerable.

I saw very few of the dark, nearly black, Cinereous vultures (Aegypius monachus). They are widespread through most of Europe and Asia, and are winter visitors in Rajasthan. This was one of a large group of vultures which was waiting near an unmoving cow. From the smell it was definitely dead, but the vultures were not yet ready to attack it. One suggestion was that the hide was too thick, and they were waiting for a red-headed vulture, with its strong and hooked beak to open up the skin. Given that the population of red-headed vultures is so small (84 in 17 districts of Rajasthan in 2009), they could have had a long wait. Also, I’ve seen single Gyps indicus (the Indian vulture) opening up a carcass. There are always parts of a body with thinner skin, or none at all. So this behaviour remained a mystery to me.

In the same crowd I saw many White-rumped vultures (Gyps bengalensis) and Indian vultures. Their numbers had crashed massively due to diclofenac poisoning, but the population is recovering slowly. A detailed study of the vultures Rajasthan was published eight years ago, and makes for interesting reading today. Now that diclofenac is not as much of a problem as it was then, the numerous other conservation bottlenecks pointed out in the study have come to the fore. Habitat loss due to quarrying and mining was pointed out as one major cause. I saw that quarrying is widespread in the desert. Electrocution in power lines is another cause which has been identified. All large birds are subject to this problem.

The mixed flock of Indian and White-rumped vultures which we saw in our first morning in the desert seemed to indicate that some pockets of vulture populations still remain. The IUCN red list still classifies them as critically endangered. This was the largest crowd of vultures I saw since 2005, when I saw them stealing from a tiger. I can understand why some naturalists are interested in the population genetics of vultures. Recovery of numbers from such a tremendous bottleneck may cause vultures to lose much of their genetic diversity. The government’s action plan involves setting up captive breeding centers. But these need to also preserve diversity of genes. Vultures a really fighting for survival, and it is still hard to sat whether they will survive another human lifetime.

The making of the Thar desert

As we drove through the Thar desert, I wondered about the mysterious landscape around me. India receives so much rainfall from the monsoon that it is hard to believe that it contains a desert. The popular belief that the monsoon winds are “depleted” of moisture by the time they reach the desert is false. The distance to the sea is rather small, and the air is generally moist. In just three winter months, when the rest of India is dry, the amount of water deposited by dew in the desert is between 30% and 40% of the total rainfall. Something prevents the western branch of the monsoon from penetrating into Gujarat and Rajasthan.

It is believed that this is the immense high-pressure anti-cyclone that exists over the Sahara and West-Asian desert. In fact, the claim is that the monsoon winds prevent the spread of this pattern to the rest of India. Evidence for competition between the two systems is what happens when a third factor occasionally intrudes. In the infrequent episodes when a Western disturbance hits India during the monsoon, causing immediate heavy rainfall and flooding over a wide area of the desert. This means that the monsoon winds are not depleted of moisture in this region, but are obstructed from flowing by the anti-cyclone. If this conjecture is true, then a weakening of the monsoon due to climate change could allow the anti-cyclone to extend across India, making it an arid habitat.

Our jeep had long wandered off the road. The flat landscape that I’d grown used to gradually gave way to undulations. There was still a strong wind blowing dust and sand into my face, so I had my mask on. But when I looked around, the ground had changed. Until a minute ago we were driving through hard packed sand (see the featured photo). Now, all around us I could see something different poking through the sand. The photo above shows the surface. The broken flat stones are made of a material called calcrete. This is formed by the action of water and atmospheric carbon dioxide on wet dust and sand (the word calcrete seems to be a portmanteau of calcium and concrete). The presence of calcrete means that wet lands turned to desert at some time in the past. Dating of calcrete in the Thar desert shows repeated cycles of wetness and desert starting from 1.5 million (15 lakh) years ago to 250,000 years ago.

I walked across this landscape in search of a wheatear, but my attention was on the landscape. A short walk through sand brought me to something that looked like a dry riverbed into which sand had trickled: calcrete was overlain with sand, as you can see in the photo above. Aerial and satellite photography shows evidence for a well-organized drainage system of interlinked rivers in the far past, disrupted by climate change. Successive surveys and dating showed brief re-emergence of local drainage systems over a period of a million years, which were disrupted within a few tens of thousands of years.

The wheatear perched briefly on a bush and I managed to take a photo. After it had flown off, I looked at the land behind the bush (photo above) and it became obvious that it had been shaped by flowing water. The surface was covered in calcrete, which it why it had not been reshaped by the wind. Studies of pollen around Didwana lake in the eastern part of the desert have established that about 6500 years ago the area was wet enough to support a large variety of grasses and flowering herbs and shrubs, of the kind which are usually pollinated by butterflies. This dried up around 4000 years ago. When these studies were first published, there was speculation in the press about the connection with the mythical river called Saraswati. More studies revealed a fluctuating boundary of the desert over human history and pre-history. Palaeolithic tools and sites have been found buried intact in the sand, showing that the desert shifts fairly abruptly. The gradual abandonment of Harappan cities could also have been partly due to such climate fluctuations.

The bird gone, I climbed a little bluff to join The Family, and saw immediately clear evidence that I had walked across the bottom of an ancient river. The photo above makes it very clear. How old was this? I’m sure it has been mapped out. The geological and climatic history of the Thar desert has been examined in great detail in the last 60 years by a large number of scientists working in India. There is a group in IIT Mumbai who examined the age of sand dunes, and found some as old as 160,000 years, and others as young as 11,000 years. In several of the photos above, you can see distant dunes. It gives me shivers to realize that they were being laid down at the same time as glaciers advanced across the north of Europe, Asia and the Americas. As water got locked up in ice, this part of the world turned dry.

Geology and climate sculpt the land over periods longer than our lives, even longer than our civilizations. As a result, it has been hard to see the forces which shape our societies. Walking across that river bed I thought that I had a tiny view of these forces. In the past our actions have been too weak to shape the planet. No longer. We need to understand the Thar desert to plan a way ahead as the climate changes.

Winter phog

The tall bush which you can see on the right hand edge of the featured photo is called phog in Hindi, and Calligonum polygonoides by botanists. Other clumps can be seen on further dunes. Each thicket can grow about as tall as a human, and spreads out in a circle. Unfortunately, I visited the Thar desert in winter, when one does not get to see the flower or berries of the phog. The flowers and buds are eaten as a raita, the shoot is used as feed for livestock and the root is used to make charcoal. The deep tap roots and lateral root system together contain a larger biomass than shoots.

As you can see from this panoramic shot, the plant grows very well in the extremely arid habitat of dunes where little else grows. As a result, it serves to stabilize the dunes. Over-exploitation of the plant to produce charcoal used by goldsmiths and local ironsmiths has begun to endanger the phog. There are attempts to propagate the plant through cultivation and replanting, but this has not been uniformly successful. Studies of competition between the phog and other varieties of desert grass shows that in more moist conditions the phog loses out. Consistent with this is the fact that growth of C. polygonoides changes soil properties less than other plants do.

Of more than 80 species of Calligonum recorded worldwide in arid areas of southern Europe, northern Africa, west and central Asia, only this one species grows in the Thar desert of India. A recent study found very high degree of genetic diversity in the phog population in Rajasthan. However, there was no geographical clustering of varieties. When I talked to an expert, I was told that the confused state of this first study makes this subject worth a second look. After reading the scant literature on this plant, I would be willing to do such a study if I had the expertise and the means.

Cranes of Khichan

We took a detour between Jodhpur and the Desert National Park to pass by the now-famous village of Khichan. This is a place to go to if you want to see Demoiselle cranes in winter. These elegant gray cranes, Anthropoides virgo, come to north India for the winter. Khichan became a wintering ground some time in the 1970s when the local Jain community started feeding birds. (Interestingly, the person who started the feeding of cranes remembers the month, September, when he first saw them, but is a little vague about the year.) This attracted the birds in growing numbers, and the locals responded with enthusiasm. Now several thousand birds can be seen feeding here in season. We came on them in the mid-morning, and saw a flock of several hundred picking at the seeds put out by the villagers.

Looking at a large mass of birds can be a treat. When many species are declining, it is nice to come across as species which is actually increasing in numbers. The Demoiselle has accomplished this by adjusting to a life on farmlands instead of the ever-declining grasslands habitat. Of course, this brings it into conflict with humans. After a while I began to pick out groups of birds which seemed to move together or cluster near each other. This was not an illusion. The large migratory flocks of the Grus virgo are made of smaller social groups. Apparently they live in smaller flocks during the breeding season, gathering together only for the migration and wintering.

The birds are monogamous, a breeding pair stays together. One of the things that we were unable to see is the spectacular courtship dance. The cranes of Khichan would have finished their dances and courtship calls in the grasslands of Mongolia, and raised their young during the long summer. We could still see the differences in plumage between the adults and immature birds. As you can see in the photos above, adults of both sexes are blue-grey in colour, the head is lighter gray, the neck black, there is a long white plume from its eyes hanging down to the back, and their eyes are red. The immature are duller in colour, and the plume may be less well-developed. The legs and feet are black, and the bills are light yellow turning to a pink or orange at the tip. I found the multiple levels of social organization amazing: small flocks of breeding pairs coming together into a large migration.

We watched the Demoiselles until they took flight. All cranes have similar postures in flight: neck and bill held out in a line, the body straight, and the legs lifted into a straight line perfectly aligned with the bill. There are scattered references to an unpublished satellite tracking study of the migration of Demoiselle cranes from Mongolia to India. Apparently it was found that flocks which winter in India travel over the Himalayas with extremely few rest stops. The path over the Annapurna range is supposed to be the most difficult high altitude migration route taken by any species of cranes. It seems that the Kali Gandaki river valley provides an access path through this high range; in 1979 more than 61,000 A. virgo were counted passing through a point in this river valley in twelve days. Demoiselle cranes were observed to fly at heights of between 5 and 8 Kms above sea level, and descended to lower altitudes over the valley only in bad weather.

It seems that all cranes are able to store fat in their bodies so that they can make longer flights without stopping. Interestingly, it seems that this does not elevate blood cholesterol and triglyceride levels in these birds. If only this were also true of humans!