Frank H. Neumann

Predictability of biomass burning in response to climate changes

Climate is an important control on biomass burning, but the sensitivity of fire to changes in temperature and moisture balance has not been quantified. We analyze sedimentary charcoal records to show that the changes in fire regime over the past 21,000 yrs are predictable from changes in regional climates. Analyses of paleo- fire data show that fire increases monotonically with changes in temperature and peaks at intermediate moisture levels, and that temperature is quantitatively the most important driver of changes in biomass burning over the past 21,000 yrs. Given that a similar relationship between climate drivers and fire emerges from analyses of the interannual variability in biomass burning shown by remote-sensing observations of month-by-month burnt area between 1996 and 2008, our results signal a serious cause for concern in the face of continuing global warming.

Climate change and human disturbance of fynbos vegetation during the late Holocene at Princess Vlei, Western Cape, South Africa

Pollen analysis of a core in Princess Vlei in the Fynbos Biome near Cape Town gives a 4150 year record of vegetation and climate changes followed by disturbance by colonial settlers since c. 300 years ago. Their impact replaced climate as a major factor in changing the vegetation. The chronology is based on eight radiocarbon dates. Pollen types such as Restionaceae, Ericaceae, and Proteaceae reflect changes in fynbos. Pollen indicators at the bottom of the core suggest drier conditions followed by an increase in Morella, Cyperaceae and Carpacoce pollen, which might indicate moist conditions c. 3400–2600 cal. yr BP. Drier conditions prevail c. 2600–1900 cal. yr BP. Apparent light disturbance after c. 2000 cal. yr BP might be attributed to Khoi herders. Deeper water and damp surroundings are indicated c. 1900–1000 cal. yr BP. The top of the core shows an increase of Poaceae while Restionaceae decrease with anthropogenic disturbance, including the introduction of neophytes such as Pinus (c. 300 years ago) and Zea mays. Charcoal percentages point to intense fires after the arrival of the Europeans. Water between 105 and 75 cm indicates the development of a floating mat resulting from changes in the hydrological system possibly connected to disturbances by settlers.

Archaeological Reconnaissance for Middle Stone Age Sites Along the Pondoland Coast, South Africa

Part of the phytolith analysis was supported by the Ministerio de Ciencia e Innovacion (HAR2010-15967 to Albert). The field survey was funded by a grant from the National Geographic Society / Waitt Foundation (W160-11 to Fisher)

Shaping of modern southern African biomes: Neogene vegetation and climate changes

Long-term trends in climate, hydrology and geomorphology contributed to the formation of the current biomes of southern Africa. The Neogene terrestrial fossil record is patchy, due to the geomorphological evolution of the subcontinent and the restricted distribution of suitable sediment deposits. Here we review the hypotheses on the evolution of the topography and environment and concentrate on the fossil record, especially pollen, wood, charcoal, leaves and biomarkers. Tectonic studies suggest a lower relief landscape than at present at the onset of the Neogene. Southern Africa was drained by two river systems – the Kalahari and the Karoo Rivers – and was affected by an initially weak, cool Benguela current along the western coastline, gradually promoting an aridity trend along the southwestern coast. The Cape region during the Miocene, when the Great Escarpment began to evolve, was characterised by humid, subtropical forests not unlike those still occurring on the much wetter subtropical eastern shore of southern Africa. Southern Namibia (Sperrgebiet) was probably covered by a “proto-savanna”; hyper-aridity developed further north along the Namibian coast. Probably with more uplift, the hydrological regime changed c. 15 Ma when the palaeo Karoo and Koa Rivers were captured by the Kalahari/Orange River and drained western South Africa. Miocene fossil sites are missing in southeastern Africa. In southwestern Africa an enhanced aridity trend and the shift to a winter rainfall regime during the late Miocene-Pliocene was triggered by the development of the Westerly wind system and further strengthening of the cold Benguela current enhanced by the development of the Antarctic sheet and opening of the Drake passage. Eastern southern Africa was dominated by the Great Escarpment and relatively shorter deeply incised rivers and higher rainfall than the west. The Pliocene saw the evolution of the Fynbos and Succulent Karoo biomes including the further radiation of several drought adapted plant families encompassing the Asteraceae and Aizoaceae. At the transition towards the Pleistocene, the region around Sterkfontein in eastern central southern Africa, important for hominid evolution, experienced a shift from a woody environment towards more xeric, open conditions. The Savanna biome today stretches from northeastern South Africa as far north as East Africa; the Grassland and Fynbos biomes are unique and the more arid biomes are dominant in the western half of southern Africa.

The Earliest Post-Paleozoic Freshwater Bivalves Preserved in Coprolites from the Karoo Basin, South Africa

Background Several clades of bivalve molluscs have invaded freshwaters at various times throughout Phanerozoic history. The most successful freshwater clade in the modern world is the Unionoida. Unionoids arose in the Triassic Period, sometime after the major extinction event at the End-Permian boundary and are now widely distributed across all continents except Antarctica. Until now, no freshwater bivalves of any kind were known to exist in the Early Triassic. Principal Findings Here we report on a faunule of two small freshwater bivalve species preserved in vertebrate coprolites from the Olenekian (Lower Triassic) of the Burgersdorp Formation of the Karoo Basin, South Africa. Positive identification of these bivalves is not possible due to the limited material. Nevertheless they do show similarities with Unionoida although they fall below the size range of extant unionoids. Phylogenetic analysis is not possible with such limited material and consequently the assignment remains somewhat speculative. Conclusions Bivalve molluscs re-invaded freshwaters soon after the End-Permian extinction event, during the earliest part of the recovery phase during the Olenekian Stage of the Early Triassic. If the specimens do represent unionoids then these Early Triassic examples may be an example of the Lilliput effect. Since the oldest incontrovertible freshwater unionoids are also from sub-Saharan Africa, it is possible that this subcontinent hosted the initial freshwater radiation of the Unionoida. This find also demonstrates the importance of coprolites as microenvironments of exceptional preservation that contain fossils of organisms that would otherwise have left no trace.

Sedimentology, isotopes and palynology of late Holocene cores from Lake Sibaya and the Kosi Bay system (KwaZulu-Natal, South Africa)

This study documents a multi-proxy palaeoecological record spanning 2000 years for the northern KwaZulu-Natal coastal plain. Data are presented from cores recovered from Lake Sibaya and the northernmost coastal flats of the Kosi lake system. Sedimentation rates are higher in the dated Sibaya core than in the Kosi core. Carbon isotopic values from all three cores suggest that C3 plants have been the dominant biomass, with some C4 plant input at certain depths/times in the cores. Low nitrogen isotopic data in the cores suggest that nitrogen fixation processes occur in both systems. Due to high sample distance and often low pollen concentration, palynological data are restricted to a single core at Lake Sibaya. The pollen assemblages reflecting changes from greater forest abundances to greater savanna grassland abundances support results from a previous palynological study at the lake. The relative proportion of carbon in the samples decreases during the same time frame, potentially reflecting a decline in biomass volumes at the two ecosystems. Human impact is evidenced by the appearance of pine and probable maize pollen in the upper section of the core.

Transfer Functions for Paleoclimate Reconstructions — Applications

The aim of this study was to describe the applicability and the use of transfer functions in paleoclimate and paleoenvironmental research. In this chapter, different proxies (i.e. pollen, diatoms, carbon isotopes) were used in order to reconstruct the regional climate and environmental history throughout the Holocene. Case studies based on WA and WA-PLS transfer functions using diatoms showed the capability of siliceous algae to record environmental and climatic changes. However, the paleotemperature reconstruction from diatoms and their comparison with a pollen-based temperature reconstruction at Lake Lama, Siberia only revealed similar trends indicating different processes affecting the diatoms and pollen. The WA-based TP reconstructions from diatoms at Lake Woserin and Lake Holzmaar, Germany showed the response of the organisms to increased anthropogenic activities additionally to climate. Temperature reconstructions using carbon isotopes from tree-rings at high elevation sites of the Tibetan Plateau indicated that tree growth is temperature limited, although anthropogenic effects of changing atmospheric δ13CO2 and pCO2 may influence the calibration with measured meteorological data. Beside these reconstructions, we presented the methodology of a probability-based approach for a paleoclimate reconstruction using pollen distributions from sediments of the Dead Sea which is currently carried out.

Galilee Blooming: First palynological and archaeological data from an Early Byzantine Cistern at Horvat Kur

Abstract Preliminary archaeological and palynological results are presented from an early Byzantine cistern of the village Horvat Kur in eastern Lower Galilee/Israel. The rural site was settled from the Hellenistic until the Early Arab period, its synagogue was constructed shortly after 425 AD and renovated sometimes during the 2nd half of the 6th century AD. It was abandoned probably as a consequence of the earthquake of 749 AD. The intact and properly sealed cistern contained complete or fully restorable pottery. Two cooking pots from the early 5th century AD comprised sediments which was sampled for palynological purposes. Both samples, as well as a sample from the soil beneath one of the pots and a modern surface sample from the site, revealed well preserved palynomorphs in comparably high concentration showing a great potential of the cistern as a pollen archive. The pollen content points to an open, grassy semiarid landscape with an apparent scarcity of cultivars and trees in the vicinity of the site and an abundance of herbs, especially Asteraceae, which are still commonly found in modern regional vegetation.

New fungal cephalothecoid-like fructifications from central European Neogene deposits

Fragments of cephalothecoid fructifications (peridia) were encountered during palynological investigations of Neogene deposits in Mizerna-Nowa/Poland and Adendorf/Germany. Isolated plates of cephalothecoid ascoma in shape and cellular structure similar to the extant members of the family Cephalothecaceae are described as Cephalothecoidomyces neogenicus fossil gen. et sp. nov. while remnants of fungal sporocarps with cephalothecoid walls with indistinct lines of dehiscence, similar in structure to peridia with cephalothecoid morphology of extant representatives the family Chaetomiaceae (mainly genus Chaetomidium) are assigned to Adendorfia miocenica fossil gen. et sp. nov. We also propose a new interpretation of some previously described fossil fungal taxa that we consider to be remnants of cephalothecoid ascomata.