British Cactus & Succulent Journal, Volume 14 Number 3 pag. 139-145

Destruction of a Well Known Habitat and Measures to Preserve It
by Norbert Gerloff: edited by Rene Zahra

Photos by Norbert Gerloff except where otherwise stated

On each of my five trips to the Brazilian state of Rio Grande do Sul together with local friends I visited the big mountain called Pedra do Segredo (Secret Rock) 10 km south-west of Cacapava do Sul. On the north flank of this 500 metre high mountain growing with Tillandsia aeranthus you can find Notocactus scopa var. brasiliensis n.n. (HU 1). These can be found on a 70 metre high vertical wall. The whole top region of this 2 km long mountain is also the habitat of Notocactus arachnites F. Ritter (HU 9). (See Figures 5 & 9, of a typical plant near a Dyckia). On his journeys through Rio Grande do Sul, Leopoldo Horst, who before 1961 was a travelling salesman, was shown by the locals the habitats where cacti grow. In fact all the low HU field-numbers (1 to 13) are of cacti that grow in the region from Cacapava to Lavras do Sul, and on the roads between these two places (see list). When Horst got in contact with Werner Uebelmann a lot of these places became well known. One of these places is the habitat that I am writing about in this article. (See drawing of Pedra do Segredo).
To understand this region it is important to know something about the geology of this mountain, and to understand the process of the erosion that has shaped the region. In the last million years wind and rain has formed a 250 metre deep valley in the granite rocks. With this process some weird, crazy sculptures have been formed in this Quaternary strata. The name Pedra do Segredo from which the mountain gets its name is actually given to a 30 metre diameter stone ball found in this area. In the underlying flat horizontal areas there is a layer of conglomerate from the Carboniferous era. Here hard, round stones like billiard balls are embedded in a soft material. With the rain the soft material is quickly washed away, and the round, hard stones that are left behind are very difficult to walk on for both men and cattle alike (see drawing of typical habitats).
The whole area is owned by two persons who use it for the pasture of cattle. Each of them owns between 110 and 140 acres of land. Where there is only a thin layer of humus some grass can grow, but where this layer is a little thicker one can find big bushes and some trees too. On the whole mountain you can find fields of Dyckia remotiflora with orange flowers (see Figure 14). The clumps of Dyckia hold the humus in place during the rainy season and between them we found Echinopsis oxygona, Frailea horstii, and Notocactus arachnites. In this area rain falls mainly in the summer and this could be as much as 2,000 mm per annum. Figure 2 taken in 1995 shows a much greener mountain than Figure 1 taken in 1989 during the hot dry summer period. For the last three years this area has received a lot of rain. This was very good for cacti, but not so good for us during our trips.
The cattle that roam this area eat all green plants including the platyopuntias, and Pipthanthocereus alacriportanus, what they don't eat is a kind of thistle that the Brazilians call 'grawata'. This thistle is not even touched by sheep and goats. The grawata grows up to about 1.5 metre high. (See Figure 4). Late in the summer (in this part of Brazil it is between February and March), people used to set the whole area on fire to rid themselves of these unwanted plants. In this way all the plants were burned, and so were a lot of small animals as well. A few weeks later, young fresh grass starts to grow again, and this provides new food for the cattle. This method damaged the cactus population. The big plants were burned. Some cacti lost their spines and the top part of their ribs. Only the seeds in the ground could survive. Sometimes the fire-damaged plants formed new heads, and the quick growing fraileas produced new plants after every fire.
A lot of damage is also caused by the cattle. They kick the plants with their feet. The plants are knocked onto their sides and with the roots exposed to the sun they get scorched and die (see Figure 13 of a kicked N. arachnites lying on its side). In 1994 we were introduced to a family that takes care of 16 head of cattle near the mountain top. The family comprises the mother and her two sons, aged 9 and 15, the father had left some years before. They were very simple people. After explaining to them what happens if people burn up the whole mountain we showed them how in the future they can protect the thousands of Notocactus arachnites that grow there. The older boy now hacks with a hoe the mature grawatas that grow there. If you don't do this the grawatas will take over and will push back all other vegetation. He puts them into a heap and when dry he sets them on fire. During each of our visits we replanted nearly 100 cacti hoping that they would root again, flower, and produce seeds. We showed the boys how to do this, and now both of them are replanting the big cacti knocked out by the cattle. The boys were also shown how to make little rings of stone around some plants, because in this way the cattle would not tread on and kick the plants out of the ground.
Setting fire to the mountainside once a year was much easier. Our new method involved more work for the two boys. To encourage them we had to pay for this extra work. In the first year both of them got new shoes and trousers for the first time in their lives. A friend of mine who three months later was visiting his sister in Cacapava met this family and gave them some shirts and a few Reais (Brazilian money). On my last trip, Easter 1995, we checked their activities and we were very happy to see that our collective efforts were giving very good results.


Here is our latest plant report for the above mentioned area.

HU 1 (Gf 28) The Notocactus scopa with red and white spines growing on the north flank of the mountain is not endangered. Here the plants cannot be eaten or burned. The population is about 200 to 300 plants (see Figure 10)
HU 3 (Gf 532) Notocactus crassigibbus/arachnites? We only found a few plants with larger bodies, 2 km west of the top of the mountain. The population is, maybe, about 50.
HU 4 (Gf 30/Gf 534) Notocactus langsdorfii fa. prolifer. This species is forming clumps of 20 to 40 heads. It is found only in one area. Since it grows in the stones washed out of the conglomerate, it cannot be destroyed by fire. Where whole patches of Dyckia had been burnt some time before, the ground material becomes loose and slips away to the valley below carrying with it groups of plants (see Figure 7). The population of this species is about 20 clumps. In the last five years the clumps have expanded, but we think that there are fewer young seedlings, and feel that the population is dying out (see Figures 11 & 6 taken in 1968 and 1995).
HU 9 (Gf 31/Gf 365) Notocactus arachnites. This species becomes taller than wide when it gets old. Thus it becomes pear- shaped. The largest plants we found had a diameter of 13 cm and were 20 cm high. You can find this species in the higher regions of the 2 km long top of the mountain. This is the species that in the last few years we have been trying successfully to protect. The population may be of about 500 to 2000 adult plants (see Figure 12).
HU 11 (Gf 27) Notocactus ottonis that grows on the sides of the mountain under trees and bushes is rare. The population is about 100 plants. Fire kills the older plants, but the seeds sprout in the following year.
HU 87 (Gf 376) Echinopsis oxygona, a plant with large pink coloured flowers is found on this mountain in several places. The cattle try to eat the plants and the fruits when they have fewer spines. Most plants are young. The population on this mountain is between 200 and 300 plants.
HU 1000 (FS 191) Notocactus rudibuenekeri is a new species from the scopa group, it grows 1,200 metres north of this place. This is the original habitat of FS 191/WRA 355. The white spined plants with little yellow flowers grow on a mountain that looks like Corcovado in Rio de Janeiro. Nobody can reach the plants; no cattle or even fire can climb the mountain. Here the population of some hundreds is not at risk. Ten kilometres further towards the habitat of HU 1000 (the same plant), but here nearly all the plants have been taken by collectors (see photograph of habitat of this species, Figure 3).

List of the first 13 HU field-numbers.

HU 1 - Notocactus scopa (Sprengel) Berger ex Backeb. Rincao do Segredo (= Top of Mountain).
HU 2 - Notocactus sellowii (Link & Otto) Theun. (15 km NE of Cacapava, 20 km from this place).
HU 3 - Notocactus crassigibbus or Notocactus arachnites (In 1995 I tried to clear up this question, see the photograph).
HU 4 - Notocactus langsdorfii (Lehm.) fa. prolifer (Ritter) Gerloff. This form grows only at the place where the photograph was taken.
HU 5 - Notocactus crassigibbus F. Ritter. 30-50 km south, around Lavras do Sul.
HU 6 - Notocactus langsdorfii var. longispinus (F. Ritter) Gerloff. 30-50 km south, around Lavras do Sul.
HU 7 - Gymnocalycium denudatum Pfeiffer ex Mittler. 20 km from this place in the direction of Lavras do Sul and in many other parts of Rio Grande do Sul.
HU 8 - Notocactus megapotamicus (Osten) Herter var. vulgatus. One habitat is 20 km NE of this place, but it is also found near Quevedos and Santiago.
HU 9 - Notocactus arachnites F. Ritter. On the rocks on this mountain.
HU 10 - Notocactus arechavaletae var. aureus F.Ritter. 100 km to the East, Pantano Grande.
HU 11 - Notocactus ottonis (Lehm) Berger ex Backeb. It grows in several forms around this place. On this mountain it is found in the shade at the lower regions.
HU 12 - Frailea pygmaea var. minor F. Ritter. 10 km and at 15 km NE of this place.
HU 13 - Frailea horstii F. Ritter. On this mountain - Pedra do Segredo (see Figure 8).