30 Apr 1995 - Well adapted to montane grasslands
By Rob Little, Ray Jansen & Tim Crowe
PIONEERING RESEARCH in the Natal Drakensberg during the 1980s suggested that Redwing Francolin are less tolerant of habitat manipulation than Greywing Francolin. Redwing thrived in "conserved" grasslands but were replaced by Greywing where burning was frequent and grazing pressures were moderate to high.
The "conserved" grasslands were grazed at low levels only by indigenous ungulates and were burnt biennially or less frequently. This was believed to simulate "natural" rotations of these fire-subclimax grasslands.
The highest average lightning frequencies are recorded in this "sour" mountain grassland biome, and plants in this biome tolerate and require more frequent burning than those typical of areas subject to lower lightning frequencies.
These plant populations have adapted to burning frequency according to the local probability of ignition by lightning in the areas they inhabit, and present-day responses of plant and animal communities to burning reflect their ancestral exposure to fire in the course of their evolutionary development under pre-existing, "natural" fire regimes.
The optimal burning frequency in the subtropical grasslands of South Africa varies according to the rate of litter accumulation, which is determined largely by the amount of rainfall received annually.
In "sour" grasslands, where mean annual rainfall ranges between 550 and 1950 mm, and annual primary production is correspondingly high, the foliage becomes progressively less acceptable to grazing ungulates as it matures, so that by the end of the growing season it is virtually unpalatable, and large quantities of unutilized foliage remain intact.
If left unburnt for more than two to four years, the increasing accumulation of litter begins to shade out the dominant perennial grasses, which gradually begin to die off. Thus, under a light or moderate grazing regime, biennial or triennial burning proves best for "sour" grasslands, and indeed, for the grassland francolins.
During the first half of this year Raymond and his two pointers flushed over 1000 Redwing from the grasslands on 31 properties surrounding Dullstroom.
Comparison of the densities of these populations with grazing pressures and age of grasslands since previous burns tells a vivid story of the tolerance of Redwing to land use activities.
Mean Redwing densities are only significantly above the one bird per hectare threshold for satisfactory commercial hunting of grassland francolins in two to three year old "conserved" grasslands, in this case in the Verlorenvallei Nature Reserve. Younger grasslands, either ungrazed or lightly grazed by Blesbok, produced Redwing densities which hovered about the one bird per hectare threshold.
These population levels confirm the average of 1.06 birds/ha under similar conditions in the Natal Drakensberg.
On the other hand, grasslands grazed at stocking rates of < 5.0 hectares per large livestock unit, which are also unfortunately burnt annually to stimulate new growth for grazing livestock, produced Redwing densities of significantly less than the huntable threshold.
Interestingly, another highland grassland special, the Yellowbreasted Pipit, apparently responds similarly to these variations in grassland management, i.e. they are present in "conserved" grasslands and absent from grazed grasslands.
These preliminary investigations suggest that the biological and financial value of Redwing, as a coproduct of livestock farming, in the Dullstroom region, will not compete economically with traditional livestock farming.
Furthemore, although there is very little known about the comparison
between the economics of grassland francolin hunting and profits from beef in the Eastern Transvaal, the study of the financial benefits of Greywing shooting in the Eastern Cape showed that that industry was significantly secondary to sheep farming, i.e. at best, a coproduct.
However, if Redwing can be nurtured on properties which are not used for livestock, e.g. on properties already run as profitable trout fishing syndicates, populations might be maintained at huntable levels. Therefore, dependent on the wingshooters willingness to pay, commercial hunting of Redwing alongside an array of other "environmentally friendly" land uses, might be profitable.
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Agred newsletter Summer 1995
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