Justification
Observed and projected population reduction over the last three generations and next three generations of at least 80% based on levels of exploitation (generation time ranges from 20–35 years, with a best estimate of 30 years). The population is severely fragmented and there is continuing decline in the area of occupancy and the number of mature individuals. The RAMAS® Red List software package was used to make this assessment.
Geographic Range Information
This distinctive species is found mainly in the Magaliesberg range of South Africa in the provinces of Gauteng and North West Province, with outlier subpopulations near Krugersdorp and on the Witwatersberg. Known from three locations (subpopulations). The extent of occurrence is between 3,000 and 5,000 km² (best estimate 3,809 km²), and the area of occupancy is 300 to 600 km² (best estimate 489 km²).
All regions of the Magaliesberg falling within the border of Gauteng were surveyed for Aloe peglerae by walking transects along the mountain. An average number of plants per km was calculated for regions of the Magaliesberg within urban areas and those in rural areas. The number of plants within rural and urban areas both inside and outside the province of Gauteng was then calculated by multiplying the length of the Magaliesberg (in km) by the average number of plants per km. Scattered subpopulations in Krugersdorp area were added to this number. Due to reports of small subpopulations of the plants on the Witwatersberg, a population size was assumed for the Witwatersberg.
Observed size of Magaliesberg subpopulation within Gauteng = 18,270.
Estimated size of Magaliesberg subpopulation outside Gauteng = 45,720.
Observed size of Krugersdorp subpopulation = 1,024.
Estimated size of Witwatersberg subpopulation = 2,925 (estimated using lower density figures from Magaliesberg since access higher on this range).
Results of surveys in the Magaliesberg seem to indicate that areas impacted by mining, pipelines, hiking trails, urbanization are the cause for lower Aloe peglerae densities. It is hypothesized that increased access to the Magaliesberg through these activities (especially hiking, e.g., the Aloe peglerae trail in the Rustenberg Nature Reserve has no more than 10 plants along the trail) has resulted in significant population declines of the species. Many international plant collectors and nurseries advertize Aloe peglerae plants, even though only limited trade has been recorded by TRAFFIC since 1981. Advertisements for the species range from packets of seed (15 to 10,000 seeds per packet) to plants which are sometimes advertised as wild-collected (Pfab and Patterson 1998).
It was therefore assumed that areas presently unimpacted show ideal population sizes for the species. An average of plants per km was calculated for these unimpacted areas and taken as the probable plant densities per km 60 to 105 years ago. Krugersdorp and Witwatersberg populations were assumed to be at least double their present sizes - accounts from the Witwatersrand national botanical gardens indicate that the species used to be common on the ridges of Krugersdorp area, but have declined steadily with an increase in urban sprawl.
Assumed past size of Magaliesberg subpopulation within Gauteng = 39,600.
Assumed past size of Magaliesberg subpopulation outside of Gauteng = 79,200.
Assumed past size of Krugersdorp subpopulation = 2,048.
Assumed past size of Witwatersberg subpopulation = 13,500.
It was assumed that access will continually increase with an increased impact and that harvesting of plants and seed will continue into the future. The average number of plants per km in three generations time was calculated by using current plant densities from surveys in impacted and accessible areas.
Future size of Magaliesberg subpopulation in Gauteng = 5,830.
Future size of Magaliesberg subpopulation outside of Gauteng = 19,800.
Krugersdorp subpopulation = 1,024 (no further decline assumed since all plants occur in fairly inaccessible and protected areas).
Witwatersberg subpopulation = 900 (access to Witwatersberg is expected to increase).
Habitat and Ecology Information
A stemless plant, growing singly or in small groups. Leaves about 30, in a compact rosette, curved inwards, having a reddish tint in hot weather, with the lower surface covered with a few sharp spines with white, tubercled bases. Inflorescence single, occasionally two or three, a densely-flowered, cylindrical raceme. Flowers tubular, reddish in bud, greenish cream tinged with red on opening. Flowering time July and August (Germishuizen 1997).
Grows in rocky places, often on gravelly quartzite. Confined mainly to the Magaliesberg range, usually on the northern slopes and summit, in scanty grassland and in areas with very little soil.
Threats Information
The major threat is the removal of wild plants, seedlings and entire fruiting heads from entire subpopulations by overzealous collectors. The species is expected to become locally extinct in highly accessible areas, for example, only one plant was located on cable Hill, Pretoria, a very accessible area. Urbanization has threatened the Krugersdorp subpopulation. Most of the remaining habitat falls into protected areas, hence no decline in quality, extent or area of habitat is expected.
Use and Trade Information
Conservation Actions Information
Aloe peglerae is protected in the Magaliesberg Protected Natural Environment declared in terms of the Environmental Conservation Act, 1989, Section 16. In Gauteng it also occurs in Saronde Private Nature Reserve and the Kings Kloof Natural Heritage Site near Krugersdorp. In the North West Province it is found in the Rustenberg Nature Reserve although many of the plants have disappeared from the Aloe peglerae trail, probably removed by hikers. Less than ten plants were counted along this trail during a survey in 1999.
