Afromontane Region Research Articles

Taking the scenic route – the southern Great Escarpment (South Africa) as part of the Cape to Cairo floristic highway

Background: Numerous Cape Floristic Region (CFR) clades are found in the Afromontane region of Africa, causing speculation on the source of their distribution. The southern Escarpment has been postulated as a key link in the movement of Cape species between the CFR and these Afromontane areas. Aims: The strengths of three purported connections (the north-west, Matjiesfontein and south-east) between the CFR and the southern Escarpment are considered, and of the southern Escarpment track itself. Methods: A comprehensive database was compiled from which floristic comparisons and multivariate analyses were undertaken. Palaeo-connectivity was assessed from phylogenetic relationships determined from 19 phylogenies. Results: There is evidence of both palaeo- and current connectivity between the Escarpment and the CFR, most strongly for the SE connection. Current connectivity along the southern Escarpment track is relatively well supported between the eastern Nuweveldberge and Main Drakensberg but not between the Hantam–Roggeveld and Nuweveldberge. Palaeo-connectivity along the southern Escarpment track is well supported by the phylogenies. Conclusions: Climate regime may be a more important factor in floristic connectivity than geomorphological continuity. Historical connectivity along the southern Escarpment track suggests cyclical connectivity, probably in response to glacial–interglacial cycles and associated shifts in rainfall regimes along the southern Escarpment.

Secrets of Long Life: Cross-Cultural Explorations in Sustainably Enhancing Vitality and Promoting Longevity via Elders’ Practice Wisdom

In searching for different patterns of practice, lifestyle, and environment supportive of optimal health, we look to our elders around the world, who in the wisdom that has sustained them, we learn from with careful attention. Thirty-seven elders who live by their traditions participated in the present study. They assisted in the refinement of the methodology and collections and preparation of these data. These participants are well-respected, representative elders and traditional healers of their regions. These data, from study sites of the Eastern Afromontane and Albertine Rift region of Ethiopia, Africa; the Maya Mountains region of Belize, Central America; the Western Ghats region of India; and the Appalachian Mountains region of the United States, were grouped into three major categories: (1) philosophy, attitudes, and outlook, (2) lifestyle practices, and (3) dietary and nutritional practices. These elders demonstrate a relatively comprehensive but simple set of practices that can enhance our vitality and promote longevity sustainably. In essence, these practices, or practice wisdom, of our longest living elders, promote propagation of healthful lifestyles by following traditional ways and taking care of body, mind, spirit and our environment. Further field research among a larger cohort is required to fully generalize the findings of this study, but much of it is consistent with what we already know should be done. These data begin illustration of practice wisdom for implementation and serve to engage our universities, our hospitals, our industries, and our students, who we must position toward social change.

The Boschberg (Somerset East, Eastern Cape) — A floristic cross-roads of the southern Great Escarpment

The Boschberg and Groot-Bruintjieshoogde form the wettest and floristically most distinct section of the Sneeuberg mountain complex. As such they warrant a separate detailed investigation, particularly in terms of their connectivity between the main Sneeuberg in the west, the Great Winterberg–Amatolas in the east, and with the Cape Floristic Region (CFR) to the south and south-west. Following a detailed botanical investigation and overview we conclude that the Boschberg and Groot-Bruintjieshoogde are a floristic hub between the CFR and southern Great Escarpment, as well as between the moister eastern and drier western components of the Great Escarpment. Our data confirm that the Boschberg forms part of the south-eastern connection between the CFR and the Afromontane region in southern Africa, a connection first suggested by Weimarck (1941).

The bryofloristic regions of southern Africa

A TWINSPAN classification divides southern Africa (South Africa, Namibia, Botswana, Swaziland and Lesotho) into two main bryofloristic regions: (1) a subtropical or palaeotropical region in the northern, eastern and southern parts, characterised by a predominantly mesophytic moss flora; and (2) a temperate or austral region in the central and western parts of the study area with a xerophytic moss flora. The subtropical region is subdivided into the Zambezian and Afromontane Regions, and the temperate region into the Karoo-Namib and Highlands Regions. The four regions are further subdivided into eight domains: (1) the Zambezian Region into the Caprivi and Bushveld Domains; (2) the Afromontane Region into the Drakensberg and Cape Domains; (3) the Karoo-Namib Region into the Western Cape and Namaqua Domains; and (4) the Highlands Region into the Drakensberg Alpine and Upper Karoo Domains. Meaningful phytogeographical classification of the arid and semi-arid central and northwestern sectors of the study area is dependent on future plant collecting or sampling efforts.

Exploring the Afromontane centre of endemism: Kniphofia Moench (Asphodelaceae) as a floristic indicator

AbstractAim The genus Kniphofia contains 71 species with an African–Malagasy distribution, including one species from Yemen. The genus has a general Afromontane distribution. Here we explore whether Kniphofia is a floristic indicator of the Afromontane centre of endemism and diversity. The South Africa Centre of diversity and endemism was explored in greater detail to understand biogeographical patterns.Location Africa, Afromontane Region, southern Africa, Madagascar and Yemen.Methods Diversity and endemism for the genus were examined at the continental scale using a chorological approach. Biogeographical patterns and endemism in the South Africa Centre were examined in greater detail using chorology, phenetics, parsimony analysis of endemicity (PAE) and mapping of range‐restricted taxa.Results Six centres of diversity were recovered, five of which are also centres of endemism. Eight subcentres of diversity are proposed, of which only two are considered subcentres of endemism. The South Africa Centre is the most species‐rich region and the largest centre of endemism for Kniphofia. The phenetic analysis of the South Africa Centre at the full degree square scale recovered three biogeographical areas that correspond with the subcentres obtained from the chorological analysis. The PAE (at the full degree square scale) and the mapping of range‐restricted taxa recovered two and six areas of endemism (AOEs), respectively. These latter two approaches produced results of limited value, possibly as a result of inadequate collecting of Kniphofia species. Only two AOEs were identified by PAE and these are embedded within two of the six AOEs recovered by the mapping of range‐restricted taxa. All the above AOEs are within the three subcentres found by chorological and phenetic analysis (at the full degree square scale) for the South Africa Centre.Main conclusions The centres for Kniphofia broadly correspond to the Afromontane regional mountain systems, but with some notable differences. We regard Kniphofia as a floristic indicator of the Afromontane Region sensu lato. In southern Africa, the phenetic approach at the full‐degree scale retrieved areas that correlate well with those obtained by the chorological approach.

The relevance of data on genetic diversity for the conservation of Afro-montane regions

Molecular data are shedding new light on our understanding of genetic diversity and biological diversity in general. We examine results of recent genetic studies on African birds that document endemic diversity in small, isolated montane forests of Africa. These studies show that levels of genetic differentiation in these isolated montane regions are substantial and indicate little or no gene flow with their closest populations. Although this pattern of locally distributed montane taxa is not something that has gone unnoticed by traditional taxonomists, we argue that many of the small, often outlying areas run the risk of being devalued in conservation planning because these areas generally have comparatively low levels of overall diversity and endemism (especially at the species level). We strongly suspect that other organisms will possess similar patterns of differentiation in Afro-montane regions of Africa and we argue that this information can be effectively brought to bear to highlight the conservation significance of these smaller areas.

Changes in soil carbon and total nitrogen following reforestation of previously cultivated land in the highlands of Ethiopia

Changes in soil C and total N stocks were investigated following reforestation of previously cultivated soil in comparison with soil subjected to continuous cultivation and soil under an adjacent natural forests in south central highlands of Ethiopia. Two of the most widely planted tree species in the highlands of Ethiopia, namely Eucalyptus saligna and Cupressus lusitanica, were considered in the plantation treatments. Soil C and total N contents in the upper 0–10 and 10–20 cm soil layers were significantly different in the order: Natural forest > C. lusitanica > E. saligna > Farmland. Differences in soil C and total N contents among the sites for soil depths greater than 20 cm were negligibly small and statistically not significant. Soil C and total N stocks in the upper 0.80 m mineral soil also varied significantly in the same order as above. Estimated average annual soil C accruals were 156 and 37 g C m-2 yr-1 for Cupressus lusitanica and Eucalyptus saligna, respectively. The results demonstrate that reforestation of former arable soils in the dry Afromontane region of Ethiopia could yield significant restoration of soil C and total N that are lost in the process of natural forest conversion into arable lands and subsequent cultivation. However, the two plantation species differed considerably with respect to the rate of soil C and total N accrual. This suggests that proper selection of tree species will considerably affect the magnitude and rate of soil C sequestration. Keywords: continuous farming, Cupressus lusitanica, Eucalyptus saligna, soil carbon sequestration, soil carbon loss SINET: Ethiopian Journal of Science Vol. 28(2) 2005: 99-108

No general edge effects for invertebrates at Afromontane forest/grassland ecotones

The Afromontane region of South Africa is characterised by numerous small, remnant forests in a grassland matrix. The edges, or ecotones between forests and grasslands are usually sharp (typically just over a few metres) and are mainly maintained by both natural and, more recently, anthropogenic fires. We investigated epigaeic amphipod, carabid and ant distribution patterns across Afromontane forest/grassland ecotones and found little evidence to support the biological edge effect. Five of the fifty-two sampled species however, did increase significantly in abundance at the ecotone. Among these was a very distinct edge species, the amphipod Talistroides africana. Overall, carabids were more abundant and species rich in forests while for ants it was in the grasslands. Ants and carabids were both more abundant and species rich in spring and summer than in autumn and winter. More interestingly, the abundance and species richness patterns across the ecotone did not change with the passing of the seasons. We argue that a conservation strategy for the Afromontane forest patches must also incorporate the surrounding grassland. The grassland habitat is often perceived as less valuable than forest and, as a consequence, is subject to many anthropogenic disturbances such as fragmentation, cattle grazing and afforestation. Protecting grasslands around forest patches not only conserves the rich ant diversity, but also conserves the biota in the forests and at the edges, and would therefore be more meaningful in terms of the overall conservation of Afromontane biodiversity.

ALTITUDINAL MIGRATION IN NATAL

Summary Johnson, D.N. & Maclean, G.L. 1994. Altitudinal migration in Natal. Ostrich 65: 86–94. The province of Natal, South Africa, ranges from sea level to an elevation of 3000 m over a distance of only 160 km. Evidence from the literature and from ringing shows that at least 76 species of birds are altitudinal migrants in Natal, moving to lower elevations in winter (from about March to September). Most can be grouped roughly into four categories, depending on their breeding areas (montane, high- or mid-altitude) and the distances over which they migrate (short-distance or long-distance (A) montane to high-altitude, (B) high-altitude to mid-altitude. (C) high-altitude to low-altitude and (D) mid-altitude to low-altitude; there is some overlap between the categories, some species falling into two or even three altitudinal migration patterns. Birds in category (A) move to lower altitudes from the Afromontane region of the Drakensberg regularly or only when winter weather conditions are very severe, but some individuals can be found there at all times (15 species). Those in category (B), numbering at least 16 species, leave the Afromontane and high-altitude regions altogether, but ma be found at all times of the year from the submontane region (below about 3000 m) to the midlands (down to about 1000 m). Long-distance migrants in categories (C) (12 species) and (A) (29 species) include all the remaining bird species, many individuals of which regularly reach the coastal littoral of Natal, though not all individuals of which necessarily migrate. Fifteen species cannot be categorically placed without further knowledge of their breeding and non-breeding quarters. Only further ringing will show both the proportions of migrants within a population and the distances over which they migrate each winter.

Three new mountain national parks for Uganda

For many years the Fauna and Flora Preservation Society has supported efforts to conserve forests in the Albertine Rift Afromontane Region of east-central Africa. The biodiversity of these forests is especially high but most have been destroyed or badly degraded. There are a large number of local, national and international initiatives to conserve at least some of the forests that remain. In 1991 Uganda created the Rwenzori Mountains, Mgahinga Gorilla, and Bwindi-Impenetrable National Parks, thus protecting all three of its Albertine Rift montane forests. This paper presents a synopsis of the conservation values of these three parks, and describes the conservation problems and the efforts to help ensure their proper development and long-term viability. Considerable progress towards the conservation of all three areas has already been made and future prospects are good, particularly for the mountain gorilla Gorilla gorilla beringei.

Special Paper: A Palaeoecological Perspective on the Origin of Afromontane Grasslands

This paper offers a review and reassessment of the biogeography of the Afromontane region. Much of the montane vegetation of Africa, especially in the southern part of its distribution (the southern Afromontane region) is characterized by a mosaic of forest 'islands' in a 'sea' of grassland, with or without heathland elements. Controversy has arisen as to the origin of these grasslands and the view has emerged, based on a variety of phytogeographical, zoogeographical, ecological, pedological and historical evi- dence, that the grassland element has been derived, or at least markedly extended, in the recent past by forest clear- ance through human agency. An alternative hypothesis holds that the grassland is a much older component of the Afromontane landscape. The paper assesses these two op- posing viewpoints in the light of published palaeoecological and biogeographical evidence not previ- ously brought to bear on the problem of Afromontane grassland origins in general. The physical environment and vegetation of the southern Afromontane region is reviewed and the suggestions put forward to account for the wide- spread occurrence of grasslands in the region are presented. The competing hypotheses are then tested against data on plant species richness and diversity from a number of upland areas within the region and against published Qua- ternary palynological data from the Nyika Plateau, Malawi, the Inyanga Mountains, Zimbabwe and the Winterberg Escarpment area of South Africa. The resulting reassess- ment offers strong support for the idea that the grasslands have been prominent in the southern Afromontane region since before the permanent occupation of the mountains by people. Environmental changes, especially of the late Qua- ternary, are suggested as having been important in establishing the vegetation pattern and, while increased magnitude of human impact in recent times is apparent, the so-called 'relict' nature of montane forest patches is ques- tionable. It is argued that the southern Afromontane grasslands are themselves relict from a time, around the last glacial maximum, when the climatic conditions were more suited to these formations than to forest.

Endemic flora of the north-eastern Transvaal Escarpment, South Africa

The endemic seed plant flora of the north-eastern Transvaal Escarpment (part of the Afromontane Region) is assessed in terms of the region's lithology (mainly rocks of the Transvaal Sequence). A total of 81 species and infraspecific taxa are endemic or near-endemic to the quartzitic and related rock types of the Black Reef Quartzite Formation, Wolkberg Group and Timeball Hill Formation (c. 3880 km 2) and a total of 32 species were recorded as endemic or near-endemic to the dolomitic Chuniespoort Formation (c. 2100 km 2). As a major centre of biodiversity, we propose to name this escarpment region of Transvaal Sequence, the Wolkberg Centre. Two subunits of endemism are recognized: the Blyde Subcentre in the south, and the Serala Subcentre in the north. Although the number of endemics on dolomite is less than half the number on quartzite-derived substrates, the degree of endemism is higher on the former. The majority of dolomite epidemics are confined to the drier areas and are not of such strong Afromontane affinity as the quartzite ones. Nearly all the endemics are herbaceous, confirming to the observation that regional endemism levels in the Afromontane Region are high in grassland, but low among the tree flora of the patches of undifferentiated evergreen forest. The vegetation of the Wolkberg Centre, especially the grassland, is under considerable pressure, particularly from the timber industry and invasive alien plants. Existing and proposed conservation areas in the centre are listed.

Compliance of a biennial mullein (Verbascum sinaiticum Benth.) to erratic desert floods in the Negev highlands, Israel

Wadis of the Negev desert highlands are characterised by irregular flash floods and, consequently, their beds typically comprise coarse gravel. The biennial Verbascum sinaiticum Benth. tends to establish temporary stands on such wadi gravel beds, and these exhibit a contagious pattern of distribution. V. sinaiticum, which is native to the Afro-montane region, acquires a fugitive character in the Negev. Its seeds germinate mainly on the third or fourth days after wetting. Optimal germination was obtained in continuous light at 25°C; a gradual increase in Nacl, up to 80 m M caused a delay in germination and reduced the daily rate. Irregular fluctuation of the water regime and the unstable nature of the wadi beds are essential for the establishment of V. sinaiticum. Flash floods are also necessary for its existence: they provide periodic reformation of the disturbed habitat, removal of potential competitors, dispersion of the seeds of V. sinaiticum and wash-out of excess salts. Another mullein, V. fruticulosum Post, a perennial herb, occupies the shoulders of the same wadis, as well as the terraces above them. Its distribution is sparse and the pattern tends to be random. The rôle of floods in the allopatric distribution of the two species of Verbascum is discussed.

The biomes of the eastern Cape with emphasis on their conservation

The four major phytochoria of southern Africa, the Cape. Tongoland-Pondoland. Karoo-Namib and Afromontane regions, converge in the complex transition zone of the eastern Cape. The area is rich in species and communities with a complex vegetation in which are represented all the major vegetation formations of southern Africa — Cape Fynbos. Cape Transitional Shrublands, Subtropical Thicket. Karoo, Savanna, Afromontane Forest, Grasslands and Littoral Strand Vegetation. Our results support previous findings that, although species-rich and of great diversity, the flora has fewer endemics (205 or 5,6%) than the Cape (73%) or Karoo-Namib (35%). The communities with the largest proportion of endemics (30%), and threatened plants (18%) are those of the Subtropical Thicket. On the basis of these data and an index of conserv ation status, the Subtropical Thicket was determined to be highest on the priority list for conservation in the eastern Cape. Subtropical Thicket is being cleared at an increasing rate and is most vulnerable due to changing farming practice.

The disjunct distribution of Carex peregrina confirmed

Carex peregrina Link, currently considered an endemic of the Azores and Madeira, is shown to have a disjunct distribution with occurrences also in the Afromontane Region of Ethiopia and E Africa.