Philip Desmet

Speciation in the Mesembryanthemaceae

Go to AGRIS search. Aloe (1998). Speciation in the Mesembryanthemaceae. ...

Population ecology of tree succulents (Aloe and Pachypodium) in the arid western Cape: decline of keystone species

Biodiversity and Conservation, 1997

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Namaqualand—A brief overview of the physical and floristic environment

Journal of Arid Environments, Sep 1, 2007

This paper provides a brief introduction to the physical environment of Namaqualand as well as an... more This paper provides a brief introduction to the physical environment of Namaqualand as well as an overview of patterns of plant diversity. The diverse array of parent material and geological processes that have shaped the region since the break up of Gondwanaland have created a complex, and sometimes dynamic physical environment, that is partly responsible for the patterns and processes observed in the biota today. The contemporary climate is characterised by relatively reliable, albeit low (50-250 mm pa), winter rainfall (460% winter precipitation) arriving between May and September. East of the central mountains, tropical thunderstorms penetrate the region in late summer (February-April). The presence of the cold Atlantic Ocean in the west not only moderates temperatures throughout Namaqualand (mean max summer temperature o30 1C), but also provides alternative sources of moisture in the form of coastal fog and heavy dew experienced in winter months. Recent analyses show that the flora of the Succulent Karoo is part of the Cape Floral Kingdom, now termed the Greater Cape Floral Kingdom. It is one of only two desert regions recognised as a global biodiversity hot-spot and contains an estimated 6356 plant species in 168 families and 1002 genera. Namaqualand, which comprises about one quarter of the area of the Succulent Karoo, contains about 3500 species in 135 families and 724 genera, with about 25% of this flora endemic to Namaqualand. This remarkable diversity, however, is not distributed evenly throughout the region, but is concentrated in many local centres of endemism usually associated either with quartzite mountain complexes or lag-gravel plains (quartz-patches). A major exception to the general pattern of centres of diversity is the true Fynbos vegetation of the highest Kamiesberg peaks where rainfall exceeds 400 mm pa. Suggested determinants of the region's exceptional floral diversity include the complex physical environment, a unique past and present climate and the region's diverse fauna, most notably insects. The challenge for the current inhabitants and scientists

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Extraordinary high regional-scale plant diversity in southern African arid lands: subcontinental and global

... This region includes the winter-rainfall Succulent Karoo (part of the Greater Cape Flora), th... more

Extraordinary high regional-scale plant diversity in southern African arid lands: Subcontinental and global comparisons

... This region includes the winter-rainfall Succulent Karoo (part of the Greater Cape Flora), th... more

Biodiversity – SA’s gold above the ground

Corrections to "The population dynamics and life-history attributes of a Pterocarpus angolensis DC. population in the Northern Province, South Africa" South African Journal of Botany, 1996, Vol. 62(3), pp. 160-166

South African Journal of Botany, Oct 1, 1996

Heliocephalum africanum sp. nov. is described from rock hyrax dung and is the first representativ... more Heliocephalum africanum sp. nov. is described from rock hyrax dung and is the first representative of this genus to be recovered from the Southern Hemisphere. The morphology is described using scanning electron and optical microscopy. The fungus was grown in culture, together with the bacteria on which it appears to feed. A key to the genus is included.

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In memoriam : Leslie Hill

Veld & Flora, Sep 1, 2003

In January this year Leslie Hill passed away. A man who has contributed enormously to the preserv... more

The climate of the karoo – a functional approach

Cambridge University Press eBooks, Jun 24, 1999

More species of plants are packed into the small succulent karoo landscape than in any other dese... more More species of plants are packed into the small succulent karoo landscape than in any other desert on earth, yet the vegetation is strangely homogeneous in appearance. This pattern is not repeated in the Nama-karoo, or reflected in the vertebrates of either karoo biomes. The geological history of the two biomes is similar, being sedimentary, but influenced by folding along the southern and western edges of the karoo, and by igneous intrusions in the northern and eastern parts. The soils of both biomes are typical of arid regions, and are poorly developed with little organic matter. Folding, endorrheic drainage and wind-blown movement of sand has resulted in localized patchiness in substrata which influences the biota. Anomalous soils developed along the present inland boundary between the winter and summer rainfall regions indicate past shifts in rainfall seasonality (Watkeys, this volume). Pollen core data for the past 10 000 years that indicate fluctuations between grass and shrub dominance have occurred repeatedly throughout the karoo (Meadows and Watkeys, this volume). The grass : shrub ratio still follows patterns in present-day rainfall seasonality (Palmer et al., this volume). There can, however, be little doubt that the climate of the western succulent karoo has fluctated less in the recent past and is currently more predictable than that of the Nama-karoo (Desmet and Cowling, this volume). The biota of the Succulent and Nama-karoo appear to have different geographical origins (Cowling and Hilton-Taylor, this volume; Vernon, this volume). Desert and fynbos genera are prevalent among succulent karoo plants, arachnids, insects and reptiles, whereas Nama-karoo genera have been drawn from savanna, grassland and forest, as well as from the adjacent succulent karoo and desert biomes. Climatic patterns offer some insight into reasons for the explosive speciation of succulent plants and geophytes in the western parts of the succulent karoo. In their chapter on plant biogeograhy, Cowling and Hilton-Taylor point out that the predictability of the winter rainfall in the succulent karoo is unique among desert regions. This peculiar climate has favoured short-lived shrubs that store winter

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The 2014 North West Biodiversity Sector Plan

SANBI, Jun 26, 2015

The 2015 North West Biodiversity Sector Plan

SANBI, Jun 8, 2016

The Vegetation and Restoration Potential of the Arid Coastal

3.4.1 Salinas and pan deposits 2-29 3.4.2 Sand dunes 2-29 Box 2.3 THE RED COLOUR OF SAND. 2-32 4 ... more 3.4.1 Salinas and pan deposits 2-29 3.4.2 Sand dunes 2-29 Box 2.3 THE RED COLOUR OF SAND. 2-32 4 THE PHYSICAL, CHEMICAL A.t'ID ECOLOGICAL PROPERTIES OF DUNE SOILS. 2-40 4.1 What are dune soils? 2-40 4.2 General properties of sand. 2-42 4. 3 The effect of high calcium content in dune sands. 2-44 4. 4 The thermal properties of sand. 2-45 4.5 Dune sand texture: environment-plant interaction. 2-46 4. 6 Sand-water regime in dunes. 2-48 5 CLIMATE OF THE WEST COAST BETWEEN PORT NOLLOTH AND ALEXANDER BAY. 2-49 5.1 Overview of regional climate. 2-49 5.2 Palaeoclimates of the southern namib.

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The vegetation and restoration potential of the arid coastal belt between Port Nolloth and Alexander Bay, Namaqualand, South Africa

3.4.1 Salinas and pan deposits 2-29 3.4.2 Sand dunes 2-29 Box 2.3 THE RED COLOUR OF SAND. 2-32 4 ... more 3.4.1 Salinas and pan deposits 2-29 3.4.2 Sand dunes 2-29 Box 2.3 THE RED COLOUR OF SAND. 2-32 4 THE PHYSICAL, CHEMICAL A.t'ID ECOLOGICAL PROPERTIES OF DUNE SOILS. 2-40 4.1 What are dune soils? 2-40 4.2 General properties of sand. 2-42 4. 3 The effect of high calcium content in dune sands. 2-44 4. 4 The thermal properties of sand. 2-45 4.5 Dune sand texture: environment-plant interaction. 2-46 4. 6 Sand-water regime in dunes. 2-48 5 CLIMATE OF THE WEST COAST BETWEEN PORT NOLLOTH AND ALEXANDER BAY. 2-49 5.1 Overview of regional climate. 2-49 5.2 Palaeoclimates of the southern namib.

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Improving our practice through social learning: perspectives and lessons from conservation planning in South Africa

Terrestrial ecosystem threat status assessment 2018 - comparison with 2011 assessment

Succulent Karoo Ecosystem Plan

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Vegetation Field Atlas of Continental South Africa, Lesotho and Swaziland

Ladislav (Laco) Mucina was born on 28 May 1956 in Piešťany (then Czechoslovakia, today Slovakia) ... more Ladislav (Laco) Mucina was born on 28 May 1956 in Piešťany (then Czechoslovakia, today Slovakia) and received his education in Slovakia, where he obtained various scientifi c degrees and pedagogical qualifi cations at the Comenius University and Slovak Academy of Sciences, both in Bratislava, and later at the Technical University Berlin. He spent a postdoctoral period at the University of Nijmegen in the Netherlands and later lectured at universities in Austria,

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The succulents of Northern Bushmanland: their distribution and implications for conservation

What is the Role of the Key Biodiversity Areas Program in Effective Conservation Planning

Application of Landsat-derived vegetation trends over South Africa: Potential for monitoring land degradation and restoration

Ecological Indicators, 2020

Monitoring vegetation change is important because the nature, extent and rate of change in key me... more Monitoring vegetation change is important because the nature, extent and rate of change in key measures, such as plant biomass, cover and species composition, provides critical insight into broader environmental and land use drivers and leads to the development of appropriate policy. We used Landsat data between 1984 and 2018 to produce a map of Enhanced Vegetation Index (EVI) change over South Africa at 30 m resolution and an interactive web application to make the analysis both globally applicable and locally meaningful. We found an increase in EVI of 0.37 ± 0.59% yr −1 (mean ± standard deviation), confirming global vegetation greening trends observed with lower-resolution satellites. Mesic, productive biomes including the Albany Thicket and Savanna, exhibited the largest greening trends while browning trends were dominant in more arid biomes, such as the Succulent Karoo and Desert. Although overall EVI trends correspond to vegetation index trends derived from the Advanced Very-High-Resolution Radiometer (8 km resolution), the relative scarcity of Landsat data availability during the 1980 s is a potential source of error. Using repeat very-high-resolution satellite (ca. 3 m resolution) imagery and ground-based photography as reference, we found good correspondence with EVI trends, revealing patterns of degradation (e.g. woody plant encroachment, desertification), and restoration (e.g. increased rangeland productivity, alien clearing) over selected landscapes. The utility of the EVI trend layer to government and industry for monitoring ecosystem changes will be enhanced by the ability to distinguish climatic from anthropogenic drivers of change. This may be partially achieved though interactive exploration of the EVI trends using the application found here: http://evitrend.zsv.co.za

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