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The winter-rainfall region of southern Africa, covered largely by the fynbos and succulent karoo biomes, harbours the world's greatest concentration of geophyte species. Species diversity is greatest in the south-west, where more than 500 species co-occur in one quarter-degree square; in the south-east the values are generally around 100, and in the arid north-west, always less than 50 (more often less than 10). In at least three species-rich genera (Moraea,EriospermumandOxalis), the size of storage organs (bulbs, corms, tubers) varies inversely, with the largest average values occurring in the species-poorer areas— both in the north-western, and in the south-eastern parts of the region. This negative correlation between average storage organ size and species diversity is, however, only observed at relatively large spatial scales, which suggests that there is no direct relationship between storage organ size and species diversity. More likely, both these measures are driven by winter rainfall amount and reliability, both of which peak in the south-western Cape. We suggest that reliable winter rainfall makes large storage organs unnecessary and depresses extinction rates, thus leading to the accumulation of species. [ABSTRACT FROM AUTHOR]

The article presents information on the significance of social assessment in conservation of natural resources goals in Africa. Social assessment provides an overview of the interaction between human society and its natural habitat and the prospects of future developments. Some of the other advantages of social assessment include the input of local experts and their participation on the project, understanding of humans interact with and value their natural environments that enables identification of those behavior that need to be reinforced or changed to safeguard biodiversity.

We conducted the first dynamic downscaling of Last Glacial Maximum (LGM) climate over southern Africa using a regional climate model. Eight coupled global climate model (CGCM) projections of LGM climate were downscaled to 8 km resolution, and compared to a downscaling of present-day climate. It is projected that temperatures were significantly lower during the LGM compared to the present-day, with annual average temperatures 4–6 °C lower along the eastern escarpment, south-north aligned Cape Fold Mountains and western escarpment. Southern Africa is projected to have been generally wetter during the LGM, with a significant extension in the northward reach of frontal rainfall. The largest rainfall increases are projected for the south-north aligned Cape Fold Mountains and the western escarpment of South Africa, but with rainfall decreases projected for the Cape south coast region. Rainfall seasonality is projected to have been significantly different from that of the present-day, with an all-year rainfall region plausibly extending as far north and east as the present-day Free State and Gauteng provinces of South Africa. Evaluations of the downscalings against key published proxy records for the LGM from southern Africa suggest good agreement and few deviations. • This pioneering study is the first to use a dynamic regional climate model to downscale LGM climate over southern Africa. • It provides a new source of information towards the reconstruction of LGM climate over southern Africa. • The simulations are indicative of a northward reach of frontal rainfall, confirming the interpretation of the proxy record. • The simulations provide an explanation for the observed zonal gradient in plant diversity within the GCFR in South Africa. • If suitably bias-corrected, the simulations may be used to reconstruct and interpret the palaeoscape of southern Africa. [ABSTRACT FROM AUTHOR]

Southern Africa's Greater Cape Floristic Region (GCFR) – a hotspot of biological diversity and palaeo-anthropological evidence for modern human evolution – is a climatically complex region where broad climatic gradients influence the relative importance of plant photosynthetic types in local vegetation. This mix of photosynthetic pathways imprint an isotopic signature on palaeo-records, thereby allowing for the reconstruction of historical climate and vegetation. Here, we use vegetation plot data, coupled with the photosynthetic-type affinities of plant genera, to relate their relative cover to bioclimatic drivers and use these to create spatial distribution models of C 3 and C 4 grasses and CAM shrubs across the contemporary GCFR. We then use palaeodistribution modelling, drawing on downscaled climate models for the Last Glacial Maximum (LGM), to hindcast the LGM distributions of photosynthetic types for the GCFR and its then-exposed offshore areas. In addition, we construct a model to account for the effect of lower atmospheric CO 2 concentration ([CO 2 ]) during the LGM on the competitive interactions between C 3 and C 4 grasses and use this model to hindcast relative C 4 -grass cover across the glacial-era GCFR. Our palaeodistribution models suggest that, even though there were some reductions in CAM cover and shifts in C 3 -/C 4 -dominated grass layers between the LGM and Holocene, these were mostly localised, with changes at the regional scale being relatively muted. For C 3 /C 4 grasses, distributional shifts were even more subtle once sub-ambient glacial [CO 2 ] was accounted for. Our hindcasts of glacial, [CO 2 ]-adjusted grass cover show agreements and inconsistencies with various sedimentary and herbivore-diet records in the palaeo-archive: both lines of evidence suggest the dominance of C 3 species in the strongly winter-rainfall western GCFR; in the eastern GCFR, with muted rainfall seasonality, hindcasts of relative C 3 :C 4 cover and δ13C signals from palaeo-records vary, with greater disparities between them. The lack of significant upheavals in the distribution of photosynthetic types suggests that the GCFR presented a relatively stable and dependable resourcescape for hunter-gatherer populations through the glacial–interglacial cycle of the LGM–Holocene transition. Our maps of relative C 3 -/C 4 -grass and CAM-shrub cover provide a reasonable surrogate for relative biomass of different photosynthetic types in local vegetation at a landscape scale and depict an independent estimate of carbon isoscapes across the GCFR – under both an interglacial (Holocene) and glacial (terminal Pleistocene) climate – against which palaeo-records can be assessed. • Spatial models of relative cover of CAM shrubs and C 3 /C 4 grasses under current and LGM climates • Spatial model of relative C 4 -grass cover under LGM climate and atmospheric CO 2 concentration ([CO 2 ]) • Muted changes in distribution of photosynthetic types through LGM–Holocene transition • Distributional shifts for C 4 grasses more subtle when sub-ambient glacial [CO 2 ] is accounted for • Maps of CAM-shrub and C 3 -/C 4 -grass cover can be used to assess palaeo-records of carbon isoscapes [ABSTRACT FROM AUTHOR]