Berichten weergeven met het label tracks. Alle berichten weergeven
Berichten weergeven met het label tracks. Alle berichten weergeven

zondag 28 oktober 2012

Plant circumnutation [plant growth trajectories with Mr Charles Darwin]

Cassia corymbosa: A, plant during day; B, same plant at night.

Charles Darwin is usually only known for his theoretical work (which arguable remain of some significance) but he was also an experimentalist who worked on barnacles and earthworms with meticulous care and for extended periods of time. Another subject he took on is the movement of plants. Below are trajectories of the circumnutation of various plants. Yes I needed to look that up as well: "cicumnation: The successive bowing or bending in different directions of the growing tip of the stem of many plants, especially seen in climbing plants." It looks neat though, like GPS tracks, and the accompanying explanations, like the following, add to the flavour. Who could have though that plants grow with such sense of exploration.
Brassica oleracea: circumnutation of radicle, traced on horizontal glass, from 9 A.M. Jan. 31st to 9 P.M. Feb. 2nd. Movement of bead at end of filament magnified about 40 times.

 Brassica oleracea: conjoint circumnutation of the hypocotyl and cotyledons during 10 hours 45 minutes. Figure here reduced to one-half original scale.

Pinus pinaster: circumnutation of young leaf, traced from 11.45 A.M. July 31st to 8.20 A.M. Aug. 4th. At 7 A.M. Aug. 2nd the pot was moved an inch to one side, so that the tracing consists of two figures. Apex of leaf 14 1/2 inches from the vertical glass, so movements much magnified.

Sida rhombifolia: circumnutation and nyctitropic (or sleep) movements of a leaf on a young plant, 9 1/2 inches high; filament fixed to midrib of nearly full-grown leaf, 2 3/8 inches in length; movement traced under a sky-light. Apex of leaf 5 5/8 inches from the vertical glass, so diagram not greatly enlarged.

Averrhoa bilimbi: angular movements of a leaflet during its evening descent, when going to sleep. Temp. 78° - 81° F.

Oxalis carnosa: movements of flower-peduncle, traced on a vertical glass: A, epinastic downward movement; B, circumnutation whilst depending vertically; C, subsequent upward movement, due to apogeotropism and hyponasty combined.

maandag 11 juni 2012

'Molongo' is the new buzz word

In a paper called "Long-Term Foraging Expeditions (Molongo) among the Baka Hunter-Gatherers in the Northwestern Congo Basin, with Special Reference to the 'Wild Yam Question'" Hirokazu Yasuoka "describe[s] and analyze[s] a long-term foraging expedition (molongo) among the Baka of the northwestern Congo Basin as an example Long-Term Foraging Expeditions of foraging life in tropical rainforests. On the basis of these data, I then discuss the potential of tropical rainforests as a human habitat." 

There is lot of energy intake calculating going on in this paper but for our purpose it is enough to give you a few of the images and that part of the text that explain the daily proceedings of the Baka life during the vacations expedition. What amazes me is how slow the trek proceeds. The final camp is roughly 50 kilometres away but it takes 16 days to get there while it only takes 6 days to get back. On the molongo people take it slow. 
An important sociocultural aspect of molongo is the value placed on a nomadic life in the forest. When on the move, the group would usually decamp at about eight o’clock in the morning, often breaking into several sections to variously hunt such animals as they encountered or gather plants and honey. In the early afternoon when they decided on the location of the new camp, the women began to build huts of saplings and large Marantaceae leaves, while the men again went hunting with spears or to look for honey. When fresh tracks of a large animal were found, the hunter and his assistants perused it with the gun. The Baka moved the campsite every few days before arriving at the final camp of Mongungu, where they continued to use the forest intensively for their 43 night stay. 

Once at the Mongungu camp the men set cable snares along seven routes of 2–4 km stretching in a radial pattern from the camp. Hunters visited their snares every three days, because trapped animals spoiled within two days of dying. Men searched for honey or hunted with spears on the other days. The women went out digging for wild yams every two or three days, sometimes accompanied by their husbands. The wild yam species harvested most frequently was Dioscorea praehensilis, which can be found in large quantities in one place. Almost all of the cable snares and the major gathering sites for wild yams were within 3 km of the camp, so the most intensively used area was approximately ∼30km2.
The article is behind the academic firewall, with many tanks to a reader for the PDF.

maandag 16 april 2012

Outrunning a bull Kalahari style

"Persistence Hunting by Modern Hunter-Gatherers" is a paper that deals with the outrunning of game, an ancient practise today only known to be used by Kalahari hunters. The paper does a great job describing the problems of persistence hunting, goes on to detail the environmental knowledge involved in a hunt before again moving on explain how all this is related to human energy consumption patterns. All that and more in nine pages. 
An average speed of 6.3 km/hr may not seem very fast, but the challenge to the hunter is not so much the speed as the difficult conditions that need to be overcome, including extreme heat, soft sand, and sometimes thick bush. The hunter may be slowed down when he loses the trail. The most difficult task for the tiring hunter is keeping on the right track when the animal joins the rest of the herd again, since its tracks must be distinguished from those of the other animals. When the animal is still running strongly, this can be very difficult, but when it starts to show signs of tiring it becomes easier to distinguish its tracks. Another difficulty is that the animal may circle back onto its own tracks and the hunter must decide which set of tracks to follow. The hunter does not always run on the tracks but often leaves the trail in order to pick it up ahead, and a number of times the hunter lost time following the wrong trail and then going back to find the right one. The trail may also be lost when herds of other antelope species cross the tracks. Losing the tracks was the main reason the hunters gave up in unsuccessful attempts. [The f]igure  plots the route of Karoha running down a kudu bull in October 2001, showing the kudu crossing back over its own tracks a number of times and joining other groups of kudu bulls.
When running down a herd of kudu, trackers say that they look to either side of the trail to see if one of the animals has broken away from the rest of the herd and then follow that animal. The weakest animal usually breaks away from the herd to hide in the bush when it starts to tire, while the others continue to flee. Since a predator will probably follow the scent of the herd, the stronger animals have a better chance of outrunning it, while the weaker animal has a chance to escape unnoticed.

dinsdag 5 oktober 2010

Forage Psychogeography

The above image is a classic piece of situationist every-day-life self-cartography. It is a schematic map of Paris with lines drawn between the point of origin (home) and the destination of travels made in a year. I was first published as an illustration to Guy Debord's  'Theory of the Derive' and it means to show how limited our ordinary use of the city is and how little we therefore know of our immediate surroundings; the function of the derive is to break this territorial straight-jacket. Notice that it assumes that the territory is Paris whole, the city and not the countryside, while you could argue that your territory is not a given but the space you need for your everyday needs.   

Below is GPS drawing made by Jeremy Wood of a generative psychogeographical walk in London. The idea being that the algorithm (for example: second left, first right, third left, repeat) will generate a coiling movements from somewhere to neverwhere reaching all points in between.

The current interest in the 'edible city' I find interesting for several reasons but most of all because it is a reinvention or an accidental return/rediscovery of foraging. Our fascination with roads and trails (and desire paths), and with centralized power and accumulation of wealth is a dual neolithic invention: the forager needs to travel the roads less travelled and leave the trail to survey the entire territory with intense awareness; survival depends on it. Foraging, the lifestyle of the forager, demands/creates another way to relate to your environment and your fellow people.     

Listen to Richard B. Lee and Richard Daly (The foreword to the The Cambridge encyclopedia of hunters and gatherers):  

Found among many but not all hunter-gatherers is the notion of the giving: environment, the idea that the land around them is their spiritual home and the source of all good things. This view is the direct antithesis of the Western Judeo-Christian perspective on the natural environment as a "wilderness". 

The foraging lifestyle guarantees a level of freedom and leisure that has been forever lost to those people who succumbed to the caloric revolution of agriculture 10-12.000 year ago. At the heart of the re-evaluation of the hunter and gatherer stands Marshall Sahlin's classic essay 'The original affluent society', surely the only anthropological classic to be regurlaly reprinted as a punk zine. Sahlin makes an interesting case for nomadism itself as a technique for freedom and a mindset for being out there.

Listen to Marshall Sahlin:
The manufacture of tools, clothing, utensils, or ornaments, how- ever easily done, becomes senseless when these begin to be more of a burden than a comfort. Utility falls quickly at the margin of portability. The construction of substantial houses likewise becomes absurd if they must soon be abandoned. Hence the hunter's very ascetic conceptions of material welfare: an interest only in minimal equipment, "if that; a valuation of smaller things over bigger; a disinterest in acquiring two or more of most goods; and the like. Ecological pressure assumes a rare form of concreteness when it has to be shouldered. If the gross product is trimmed down in comparison with other economies, it is not the hunter's productivity that is at fault, but his mobility. 
I would love to see a year's worth of GPS of traces of a GPS-collared nomadic Amazon Indian, but lacking these the following traces of animals make the point clear enough. The first image of the Situationist-map clearly shows a centre, a number of locations in the periphery. The various animal GPS-traces below show a full use of the territory, with the open spaces in the imaginary boundaries of its home range always ignored for a good (geographical) reason. GPS-collars generally aren't recording continuously, but make lan/lon snapshots perhaps every 12 hours, the straight lines therefore should be replaced, in one's mind, with a meandering line, suggesting an ever deeper coverage, use and knowledge of the land.

Location points (blue dots) of Alaska wolf NW025 (April 3 - June 4, 2002) connected in chronological order (red line), and the minimum convex polygon (blue line) of its home range. The cluster of locations at the top center of the home range indicates a den site.

Arctic wolf Brutus’ locations (small circles) since capture on 08 July 2009 to 30 November 2009. Each location is joined to the next consecutive location 12 hours apart with a line, resulting in what we call a “spaghetti” map.
Finland wolves Irina (n=576) and Retu (n=513) locations connected in chronological order,
April - August, 2004.

The movement patterns of collared zebra 6865 during the month of April. Zebra 6865 was collared on the 1st April and for the month of April exhibited a central place foraging strategy, returning regularly to the waterholes near to where she was collared. 

The complete movement patterns for collared zebra 6872 from 3rd April until 27th May within the Makgadikgadi Pans National Park. The movement patterns of zebra 6872 show the response to the rainfall of the 2nd and 3rd May followed by its eventual migration west to the Boteti region arriving on the 22nd May.

The collared hyena went on two excursions to the Bakers Bay seal colony, which is more than 60 km away from his western territory boundary. His home range estimate was 1400 km.

The red lines show the movements of nine caribou with GPS satellite locator collars during 2006-2007. These caribou belong to the Kenai Lowland Herd. The summer range is shown by the dense red color on the west side covering the Kenai gas fields, and the Kenai River flats to north of the Kenai airport. The winter range lies generally east of Sterling. The route lines clearly indicate that the caribou avoid roadways and developed areas. 
These are Swedish bear tracks in Sweden the underlying maps is missing to prevent poachers from utilizing the data.

Sea-routes for whales, seals and whatever, but beautiful!
Something completely different, the Apollo 11 traverse map.