A classification of the vegetation of the Etosha National Park

Roux, Camille; Grunow, J.O.; Bredenkamp, G.J.; Morris, J. W.; Scheepers, J. C.

doi:10.1016/s0254-6299(16)31355-2

Cited by 60 publications

(56 citation statements)

References 2 publications

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“…Floristic variation of southern African savanna woodlands shows a general correspondence to topo-edaphic variation (Joubert 1971;Leistner & Werger 1973;Coetzee et al 1976;Van der Meulen 1979;Van Rooyen, Theron & Grobbelaar 1981a, b, c;Coetzee 1983;Whateley & Porter 1983;Van Rooyen 1983;Le Roux et al 1988;O'Connor & Campbell 1986;O'Connor 1992), as was discerned in this study, yet the precise nature of this relationship remains elusive.…”

Section: Floristic Variationsupporting

confidence: 57%

“…Topo-edaphic conditions, woodland composition and structure, and the amount of browse are not independent of one another. Topo-edaphic conditions are an important determinant of the composition and physiognomic structure of African savannas, and structure often corresponds with composition (Leistner & Werger 1973;Coetzee et al 1976;Werger 1978; Van der Meulen 1979;Van Rooyen, Theron & Grobbelaar 1981a,b,c;Coetzee 1983;Van Rooyen 1983;Bredenkamp 1985;Bredenkamp & Theron 1985;Le Roux et al 1988;O'Connor 1992). However, these previous studies have not demonstrated a consistent finding about which topo-edaphic variables have the greatest influence on the vegetation properties of savanna woodlands.…”

Section: Introductionmentioning

confidence: 97%

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Topo-edaphic, floristic and physiognomic gradients of woody plants in a semi-arid African savanna woodland

Witkowski

O’Connor

1996

Vegetatio

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The variation in topo-edaphic conditions, woodland composition and physiognomic structure of a semi-arid savanna woodland, namely the 59 400 ha Klaserie Nature Reserve, was studied with multivariate techniques. Spatial variation in the texture and chemistry of both the A-and B-horizons was substantial. One gradient of the A-horizon was of increasing clay, silt, organic matter, pH and conductivity, while a second gradient was of increasing rockiness, slope and gravel content, associated in part with upper landscape positions. Physiognomic structure of the woodland also displayed substantial spatial variation. Variation in tree density had the greatest effect on total canopy volume, and the density of coppice and dead individuals were closely correlated. Topo-edaphic variation, after the effect of vegetation composition had been accounted for, had a direct effect on woodland structure, as clay content of soils or rockiness influenced shrub density, and catenal position together with silt-or gravel-content of soils influenced coppice density. Ordination analyses identified that the included topo-edaphic variables accounted for a significant amount of floristic variation, but also showed that important environmental variables were omitted. Floristic variation of woody elements was of the nature of a large number of relatively equivalent, independent gradients rather than of a few simple primary gradients. Ten woodland types were identified by TWlNSPAN which differed in their topo-edaphic and physiognomic character. Distinctive woodland assemblages were found on rocky outcrops or alluvial areas, on deep, sandy soils or on clay-or silt-rich soils, Colophospermum mopane formed the densest woodlands. Characteristics of the B-horizon were often dissimilar to those of the A-horizon, and seemed important for woodland composition.

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Section: Floristic Variationsupporting

confidence: 57%

Section: Introductionmentioning

confidence: 97%

Topo-edaphic, floristic and physiognomic gradients of woody plants in a semi-arid African savanna woodland

Witkowski

O’Connor

1996

Vegetatio

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“…Both aerial survey and genetic data suggest that the population has recently and historically been stable (Namibian Ministry of the Environment and Tourism 2012, unpublished data) [44]. ENP is classified as semi-arid mopane savannah [45], with annual rainfall totals around 500 mm. Rainfall exhibits a seasonal pattern with the majority of precipitation between the months of October and April (electronic supplementary material, figure S1).…”

Section: Materials and Methods (A) Study Populationmentioning

confidence: 99%

Parasite-mediated selection drives an immunogenetic trade-off in plains zebras (Equus quagga)

et al. 2014

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Pathogen evasion of the host immune system is a key force driving extreme polymorphism in genes of the major histocompatibility complex (MHC). Although this gene family is well characterized in structure and function, there is still much debate surrounding the mechanisms by which MHC diversity is selectively maintained. Many studies have investigated relationships between MHC variation and specific pathogens, and have found mixed support for and against the hypotheses of heterozygote advantage, frequency-dependent or fluctuating selection. Few, however, have focused on the selective effects of multiple parasite types on host immunogenetic patterns. Here, we examined relationships between variation in the equine MHC gene, ELA-DRA, and both gastrointestinal (GI) and ectoparasitism in plains zebras (Equus quagga). Specific alleles present at opposing population frequencies had antagonistic effects, with rare alleles associated with increased GI parasitism and common alleles with increased tick burdens. These results support a frequency-dependent mechanism, but are also consistent with fluctuating selection. Maladaptive GI parasite 'susceptibility alleles' were reduced in frequency, suggesting that these parasites may play a greater selective role at this locus. Heterozygote advantage, in terms of allele mutational divergence, also predicted decreased GI parasite burden in genotypes with a common allele. We conclude that an immunogenetic trade-off affects resistance/susceptibility to parasites in this system. Because GI and ectoparasites do not directly interact within hosts, our results uniquely show that antagonistic parasite interactions can be indirectly modulated through the host immune system. This study highlights the importance of investigating the role of multiple parasites in shaping patterns of host immunogenetic variation.

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“…Lithosols derived from andesites are relatively fertile and produce a heterogeneous vegetation type on this hilly landscape. The herbaceous stratum is perennial with Eragrostis nindensis (species group P) being very promi nent (Le Roux et al 1988). …”

Section: Leucospluiera Bainesii-colophospermum Mopane Major Communitymentioning

confidence: 99%

A comparison of Mopaneveld vegetation in South Africa, Namibia and Zimbabwe

2003

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Data from fifteen phytosociological studies were merged and classified to describe and compare the vegetation of geo graphically separated and climatically different Mopanev eld types in South Africa. Namibia and Zimbabw e. Seven v egetation types and ten major plant communities were identified using TW INSPAN. Vegetation types were separated according to geo graphical regions. There were significant floristic affinities even though there w ere geological and climatic differences between the regions. Plant communities were described according to vegetation structure, habitat and floristic composition. Although environmental data were not adequate for a detailed ordination. DECORANA reflected the distribution of vegetation types and major plant communities along environmental gradients. Limitations of large phytosociological syntheses were also addressed. Species richness (alpha diversity) was calculated for each geographical region. The Musina (Messina) region north of the Soutpansberg. South Africa, has the highest species richness, and Kaokoland. Namibia, the lowest Due to irregular annual rainfall patterns in semi-arid Mopaneveld, it is suggested that variance in species richness is associated with temporal vegeta tion states induced by rainfall events. Species richness of Mopaneveld was further compared w ith other sav anna types.

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A classification of the vegetation of the Etosha National Park

Cited by 60 publications

References 2 publications

Topo-edaphic, floristic and physiognomic gradients of woody plants in a semi-arid African savanna woodland

Topo-edaphic, floristic and physiognomic gradients of woody plants in a semi-arid African savanna woodland

Parasite-mediated selection drives an immunogenetic trade-off in plains zebras (Equus quagga)

A comparison of Mopaneveld vegetation in South Africa, Namibia and Zimbabwe

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