Phytogeographical data and modern pollen rain of the puna belt in southern Peru (Nevado Coropuna, Western Cordillera)

Aim To improve knowledge of the distribution of species and modern pollen dispersal in the puna vegetation belt (central Andes) for palaeoenvironmental analysis and reconstructions. Location Puna belt, Nevado Coropuna, Western Cordillera, Peru. Methods The vegetation facies and belts of the area were mapped by remote sensing using a March 1998 SPOT4 image. This was complemented by the interpretation of aerial photographs, by field sampling, and by the identification of plants. Data from 1940 to 1994 from the Peruvian meteorological station network were modelled to characterize the relationship between climate and vegetation. Twenty‐four soil‐surface samples were collected in the various vegetation facies identified on the map, and standard palynological techniques were applied to analyse these samples. A principal components analysis was performed on the pollen data set. Results The map shows three bioclimatic belts and seven facies in the puna sensu lato, and identifies the main plants that are characteristic of each bioclimatic area. The pollen results fit the vegetation facies and belts, including the plant species of the distinct facies that are well represented in the pollen assemblages. The mesotropical belt is characterized by the predominance of Asteraceae‐type Ambrosia; the supratropical belt shows significant frequencies of Asteraceae‐type Senecio; the orotropical belt is characterized by high frequencies of Apiaceae and includes Polylepis woodland and peat bogs; and the cryorotropical belt shows significant frequencies of Asteraceae‐type Senecio and Apiaceae. Main conclusions The pollen grains of the plants that grow on the puna sensu lato are generally entomophilous and are therefore not transported far from their plant source. The distinct bioclimatic facies and belts identified by the cartography can thus be well distinguished by their pollen production and deposition. We were therefore able to characterize the relationship between pollen, vegetation and climate that can be used for palaeoenvironmental reconstructions. An altitudinal pollen gradient on the western slopes of the central Andes was revealed by the pollen study, with the succession of Asteraceae‐type Ambrosia (1800–2200 m), Malvaceae (2700–3300 m), Asteraceae‐type Senecio (3500–4100 m) and Apiaceae (above 4600 m).     

Pollen of the Asteraceae from the Paleocene-Eocene of South Africa

Two species of dispersed pollen (Tubuliforidites antipodica and T. viteauensis) that have affinity with the Asteraceae were recovered from Paleocene-Eocene sediments of South Africa. This is the earliest unequivocal record of the Asteraceae. The two species were examined with light, scanning, and transmission electron microscopy. The pollen wall structure of both taxa are of the Anthemoid type, a pollen wall structural type considered to be primitive among asteraceous pollen. The wall structure type is indicative of many taxa of the Mutisieae. The appearance of this pollen type in the Paleocene-Eocene of South Africa supports a early Tertiary, west Gondwana origin of the Asteraceae, and the evolutionary basal position of the Mutisieae.     

Patterns of diversification in the high Andean Ponderacris grasshoppers (Orthoptera: Acrididae: Melanoplinae)

The Andes, the world's longest mountain chain, harbours great taxonomic and ecological diversity. Despite their young age, the tropical Andes are highly diverse due to recent geological uplift. Speciation either followed the orogeny closely or occurred after the Andean uplift, as a result of subsequent climatic changes. Different scenarios have been proposed to explain the diversification of high Andean taxa. The Melanoplinae grasshopper Ponderacris Ronderos & Cigliano is endemic to the eastern slopes of the Andes of Peru and Bolivia, mostly distributed between 1000 and 4000 m above sea level. Diversification in several montane habitats of Bolivia and Peru allows tests via cladistic analysis of distinct possible geographic modes of speciation. Eight species are recognized, with three described here as new with revised diagnostic morphological characters provided: Ponderacris carlcarbonelli sp.n., P. chulumaniensis sp.n. and P. amboroensis sp.n. Cladistic analyses of 15 species (8 ingroup and 7 outgroup) and 38 morphological characters, under equal and implied weighting, confirm the monophyly of Ponderacris. Characters from the external morphology and colour pattern provided less phylogenetic information than did the male abdominal terminalia and phallic complex. Species distributed in the Peruvian Andes constituted a monophyletic group, whereas those from the Bolivian Andes formed a basal paraphyletic grade. Dispersal–vicariance analysis resulted in one ancestral distribution reconstruction indicating that the most recent common ancestor was distributed in the Lower Montane Yungas of Bolivia. Eleven dispersal and one vicariant events are postulated, with a South‐to‐North speciation pattern coincident with progressive Andean uplift. Vicariance could relate to fragmentation of montane forest during the dry intervals of the late Cenozoic. From the Bolivian area, ancestral Peruvian Ponderacris may have dispersed northward, coinciding with the rise of the Andes. Ten of 11 dispersal events occurred at terminal taxa and are likely to be recent. However, diversification of Ponderacris cannot be explained solely by the South‐to‐North speciation hypothesis, but may also include both vicariance and dispersal across barriers influenced by Pleistocene climatic cycles.     

A new endemic lineage of the Andean frog genus Telmatobius (Anura,Telmatobiidae) from the western slopes of the central Andes

The amphibian genus Telmatobius is a diverse group of species that inhabits the Andes. This study analysed the phylogenetic relationships of 19 species described from the central Andes of Chile and Bolivia, and 12 undescribed populations of Chile. A molecular phylogeny based on mitochondrial DNA 16S and cytochrome b shows that the Chilean species belong to three groups: (1) the Telmatobius marmoratus group, widespread in the Chilean and Bolivian Altiplano; (2) the Telmatobius hintoni group, including the species Telmatobius philippii, Telmatobius fronteriensis, and Telmatobius huayra, occurring in the south‐western Altiplano of Chile and Bolivia, and (3) the Telmatobius zapahuirensis group, a new clade which also includes Telmatobius chusmisensis, Telmatobius dankoi, and Telmatobius vilamensis, restricted to western slopes of the Andes, and which was recovered as more closely related to the T. hintoni group than the T. marmoratus group. The divergence times between clades were traced to the late Pleistocene. The molecular phylogeny also confirmed that the groups of the Altiplano and western Andes slopes form a clade separated from the species that inhabit the eastern Andes (Telmatobius verrucosus and Telmatobius bolivianus groups), supporting the forest origin of the Altiplano groups proposed by several previous authors. © 2014 The Linnean Society of London     

Pollen calendar of malaga (Southern Spain), 1991–1995

A pollen calendar has been constructed for Malaga (Southern Spain) based on the data obtained during 5 years (1991–95) using a Burkard spore trap set up approximately 1 km west of the city. The calendar only reflects taxa which showed a 10-day mean pollen concentration equal to or greater than 1 grain of pollen/m³ of air. Twenty nine taxa are included, of which the three commonest (Olea europaea, Cupressaceae andQuercus) represent approximately 54% of the total annual count and the following four (Chenopodiaceae-Amaranthaceae, Gramineae, Urticaceae andPlantago) represent 21.3%. The greatest diversity of pollen types occurs during Spring and the highest concentrations from February to June, when approximately 85% of the total annual pollen is registered. Several peaks occur during the year principally due to Cupressaceae in February,Quercus in April,Olea europaea in May andCasuarina in October, although substantial quantities of Urticaceae, Chenopodiaceae-Amaranthaceae,Plantago and Gramineae are also detected in April and May. The pollination of important allergy-producing taxa such as olive and grass takes place earlier in Malaga than in cities more inland, so that the data presented here may be useful in predicting the beginning of the pollination season of these localities.     

Interrelation between the flower structure and composition of the pollinator groups for Dipsacaceae and Asteraceae with externally similar anthodia

The competitive relations between members of phylogenetically distant plant families Asteraceae (Centaurea and Cirsium) and Dipsacaceae (Knautia and Succisa) with purple anthodia, sharing a common wide range of pollen vectors and competing for them, were studied. The composition of pollen vectors is somewhat different in different plant species. Only bumble-bees, the most effective pollinators, were observed visiting every studied plants species. Syrphidae flies, Lepidoptera, Coleoptera, and some other insects were also observed in different proportions. The principal importance for pollination of the corolla tube size, correlating with the size of insect mouthparts, and the additional importance of particular traits of the inflorescence are confirmed. Convergent similarity of the aspect of anthodia in two species of different families is shown to be based on different structural and functional features. Insect pollinators are the factor of anthodia convergence. The plant species studied are divided into the following three groups, according to the proportion of bumble-bees among pollen vectors and to the range of species-specific pollinators; species coadapted to one pollinator taxon; species coadapted to two or three pollinator taxa; and species coadapted to many pollinator taxa. Asteraceae species in general (with the exception for Cirsium arvense) are characterized by constant contacts with a narrower range of pollinators than Dipsacaceae species (and Cirsium arvense), characterized by wider range of pollinators. Among flowering plants with similar anthodia, the tighter structural coadaptations of Asteraceae with their effective pollinators provide their greater competitive ability as compared to Dipsacaceae.     

Foraging resources of adult Mexican corn rootworm (Coleoptera: Chrysomelidae) in Bell County, Texas

Pollen analyses were used to determine pollen foraging resources of adult Mexican corn rootworms, Diabrotica virgifera zeae Krysan & Smith, captured near Temple, Bell County, TX, in 1996 and 1997. In 1996, adult Mexican corn rootworms were captured in a corn, Zea mays L., field. In 1997, nine locations outside of cornfields were added. Overall, 92% of the beetles (n = 1,323) contained pollen. More than 142,000 pollen grains were counted, representing 45 families, 63 genera, and 27 species. Overall, in 1996, noncorn grass pollen (70%) occurred in the greatest percentage of total pollen followed by corn (17%), then nongrass pollen (13%). In 1997, noncorn grass pollen (76%) had the greatest percentage, then nongrass (18%), and finally corn pollen (6%). Corn pollen was found in 34% of the beetles in 1996 and 26% in 1997. Fifteen Asteraceae taxa were encountered including sunflower, Helianthus annuus L. Thirteen Fabaceae were found including soybean, Glycine max L. Mexican corn rootworm adults foraged mainly on noncorn grass pollen, but also foraged on pollen from a large diversity of plant species, indicating that noncorn pollen may play a role in the food habits of Mexican corn rootworm adults.     

Forensic pollen geolocation techniques used to identify the origin of boll weevil re-infestation

The boll weevil, Anthonomus grandis, entered the United States of America in the early twentieth century and became a major pest in cotton, Gossypium spp. Shortly after the passage of Tropical Storm Erin on 16 August 2007 through the South Texas/Winter Garden boll weevil eradication zone, over 150 boll weevils were captured in the Southern Rolling Plains (SRP) eradication zone that was essentially weevil-free since 2003. Pollen analyses were made of the SRP weevils and weevils collected in two suspected source zones, Cameron (Southern Blacklands eradication zone) and Uvalde (Winter Garden eradication zone). An additional examination of the palynological evidence and examination of additional pollen residue shed new light on this event and strengthens the conclusion that the Uvalde area was the source of the SRP weevils. A total of 192 pollen grains from 39 taxa were found in the SRP weevils: 1904 pollen grains from ten taxa from the Cameron weevils and 148 grains from 28 taxa in the Uvalde weevils. The SRP weevils shared 16 taxa, including Phermeranthus sp. (flameflower) with the Uvalde weevils and only five taxa with the Cameron weevils. Common taxa between SRP and Uvalde weevils and the lack of the dominant ‘low spine’ Asteraceae that occurred in all Cameron samples confirm that the SRP weevils originated from the South Texas/Winter Garden zone. Problems associated with this type of research are similar to those in forensic palynology. These problems include the unknown origin of the weevils, pollen contamination and care and storage of the samples.     

Herb pollen representation in surface moss samples from mown meadows and pastures in western Norway

Grazed and mown vegetation types in western Norway were investigated with the aim of describing their modern pollen/vegetation relationships as an aid to the interpretation of fossil pollen diagrams. Pollen surface samples and vegetation data were obtained from 186 square metre plots within 39 different sites of 10×10 m. Scatter plots that show the relationship between pollen percentages and vegetation percentages are presented forTrifolium pratense-type,Trifolium rcpens-type,Lotus, Campanula-type,Succisa, Ranunculus acris-type,Cirsium-type, Asteraceae Cichorioideae,Achillea-type,Potentilla-type, Apiaceae,Rumex sect.Acetosa, Galium-type, Cyperaceae,Calluna, Plantago lanceolata and Poaceae. Pollen representation factors relative to Poaceae (R_rel) are calculated for 54 pollen taxa. Differences in the values from different geographical areas were found in the case of some taxa, due to either different genera or species being included in the pollen taxa and/or to the different representation of high pollen producers in the different regional vegetation types. Background pollen influences the estimates for taxa such asR. sect.Acetosa, P. lanceolata, Poaceae, Cyperaceae, andCalluna, and an extended R-value (ERV) model was used to investigate the magnitude of this pollen component. Groups of roughly similar pollen representation were identified and factors to convert pollen percentages to vegetation abundances are suggested.     

Botanical origin and geographic differentiation of bee-pollen produced in high mountains from the Colombian eastern Andes

In the high mountains of the Colombian Eastern Cordillera (~2000–3000 m above sea level), at the Altiplano Cundiboyacense region and surroundings, beekeepers have specialised in pollen production with substantial harvests all year round. Despite this productive advantage, the knowledge about plants used by honeybees as pollen resources is still limited. Hence, the aim of this work was to identify the botanical origin of bee pollen from this region and to examine differences between five distinguished sub-regions: Sabana de Bogotá, Fúquene, Márquez, Tundama and Norte-Gutiérrez. By means of palynological analyses of 86 pollen samples produced between 2008 and 2010, we found a total amount of 126 pollen types, most of them belonging to the families Asteraceae and Fabaceae. Major pollen types correspond to the exotic taxa Hypochaeris radicata, Brassicaceae, Eucalyptus globulus, Trifolium repens, Trifolium pratense and the native taxa Quercus humboldtii and Weinmannia sp. Differences between sample groups from the five sub-regions were mainly associated to variations in pollen abundance and frequency of native plant species. This result highlights the potential for commercialising bee-pollen from the Colombian Eastern Cordillera with geographical origin differentiation, as well as the importance for beekeeping in promoting the conservation of the natural ecosystems from the region.     

Vegetation reconstruction on the basis of pollen in Late Pleistocene hyena coprolites from San Teodoro Cave (Sicily, Italy)

Vegetation reconstruction based on pollen from coprolites of extinct spotted hyena (Crocuta crocuta spelaea, Goldfuss 1832) recovered from excavations carried out in 1998 at San Teodoro Cave (Sicily, Italy) supports previous indications of pre-Late Glacial conditions. Eight of the twelve coprolites analysed contained well-preserved pollen grains. There is a general similarity between the pollen contents from the coprolites but they show variability. They suggest a main vegetation type dominated by steppic taxa (Poaceae, Artemisia, Ephedra, Chenopodiaceae and Asteraceae) but also including arboreal taxa (Pinus and Cupressaceae). Low percentages of pollen of mesophilous woody taxa (Quercus, Betula, Abies, Alnus, Pistacia, among others) are noticeable, suggesting the existence of nearby refugia for temperate and Mediterranean vegetation. A reconstruction of the landscape, using the coprolite pollen record and other pollen records from Sicily and south Italy, shows the predominance, during the pre-Late Glacial, of a wooded steppe biome, with elements representing a variety of local environmental conditions.     

Modern pollen rain from the Biligirirangan-Melagiri hills of southern Eastern Ghats, India

A total of 39 soil surface samples collected between 11 degrees 30'N 76 degrees 45'E and 12 degrees 45'N 78 degrees 15'E from the mainly deciduous forests in the Biligirirangan-Melagiri hills of the southern Eastern Ghats were analysed for their pollen content. The samples are distributed among four different deciduous and evergreen vegetation types between 210 and 1700m altitudes and fall within three distinct rainfall regimes. The aims of this paper are to provide new data on the modern pollen rain from the Southern Eastern Ghats, a region characterized by a unique and complex climate and vegetation, and to interpret these data using multivariate statistics and the diagram of pollen percentages. We could distinguish first between the deciduous and the evergreen forests and then also between different types of deciduous forest. The distinction between the evergreen and deciduous forests was based on a humidity gradient and that among the deciduous forests on a physiognomic gradient identified through correspondence analysis. The above analysis also allowed us to identify a set of 14 pollen taxa markers and 11 associated pollen taxa that help differentiate the evergreen from deciduous forests. Similarly, a set of 12 pollen taxa markers and six associated pollen taxa was demarcated to help distinguish woodland formations from scrub and thicket formations, among the deciduous vegetation. We could also differentiate amongst the four distinct vegetation types sampled, on the basis of distinct associations of both tree and herb pollen taxa according to their relative abundance in the pollen diagram as well as on the proportion of total arboreal pollen. The ground cover of grasses and other herbaceous plants in the deciduous forests is effectively demonstrated by percentages of non-arboreal pollen varying between 40 and 70%. The 1000m altitude limit reflecting a gradient of humidity and the physiognomic gradient among deciduous forests seem to be important in this region.     

Lack of molluscan host diversity and the transmission of an emerging parasitic disease in Bolivia

Fasciolosis is a re-emerging parasitic disease that affects an increasing number of people in developing countries. The most severe endemic affects the Bolivian Altiplano, where the liver fluke (Fasciola hepatica) and its hermaphroditic snail host, Lymnaea truncatula, have been introduced from Europe. To achieve a better understanding of the epidemiological situation and the consequences of the colonization event of this invasive species, genetic analysis of Bolivian snail populations was needed. Here we compare the genetic diversity and population structure of snail samples from the Bolivian Altiplano with samples from the Old World at six polymorphic microsatellite loci. Whereas some variability exists in the snail populations from the Old World, we observe only a single genotype of L. truncatula in the Bolivian Altiplano. We discuss the possible explanations for such a reduction in genetic variability, and, given the high natural parasitism pressures exerted on the snail populations, we discuss the relevance of this result for host-parasite interactions.     

Floral resources collected by four native bees species in southern Mexico

Abstract

Melissopalynological analysis of 14 honey samples of Tetragonisca angustula (two), Scaptotrigona mexicana (six), Melipona beecheii (three) and Melipona solani (three) from Soconusco region in Chiapas, Mexico was performed. A total of 79 taxa were identified, being Asteraceae, Euphorbiaceae, Fabaceae, Melostomataceae and Rubiaceae the predominant pollen types. Melissopalynological analysis reported a monofloral composition for Melipona beecheii honeys, where the most predominant pollen type was Fabaceae (54.2%). T. angustula, Scaptotrigona mexicana and Melipona solani honey samples were multifloral and predominant pollen types were Asteraceae, Euphorbiaceae, Fabaceae, Melastomataceae and Solanaceae. The most frequent polliniferous pollen type were Asteraceae, Bernardia interrupta, Euphorbia heterophyla and Miconia. Shannon–Wiener diversity index (H′) for Melipona beecheii 2016 (2.21) and Melipona solani 2017 (1.64) were lower meanwhile honeys of Melipona beecheii 2017, S. mexicana 2017, Melipona solani 2016 and T. angustula 2017 were considered as fairly diverse, because they visited a wider range of plant species, by preferring shrub and wild strata such as: Asteraceae, Euphorbia, Euphorbiaceae, Miconia and Mimosa. Our results showed that the foraging behaviour of these bee species is polylectic, as no taxa was found to be more than 70% of the counted grains. Since the study of the collection of meliponine flower resources in the southern region of Mexico have not been studied yet, it is not possible to analyse the foraging behaviour, the use of resources and the management of these species in this region.     

Notes on the Scottish Flora

Summary

Pollen analytical investigations are described from a site on the Pass of Drumochter in the central Grampian Highlands. Three pollen assemblage zones were identified in the profile which spans the mid- and late-Postglacial periods. The earliest vegetational record is of birch and hazel woodland, which was in turn succeeded by the establishment of pine forest, possibly around 7000 B.P. Declining arboreal pollen percentages and increased values for open-habitat taxa in the upper reaches of the profile reflect the impact of Neolithic man in the area, with the destruction of the forests, and the spread of dwarf shrub heath and heather moor across formerly wooded hillsides.     

Geographical Information Systems risk assessment models for zoonotic fascioliasis in the South American Andes region

The WHO recognises Fasciola hepatica to be an important human health problem. The Andean countries of Peru, Bolivia and Chile are those most severely affected by this distomatosis, though areas of Ecuador, Colombia and Venezuela are also affected. As part of a multidisciplinary project, we present results of use of a Geographical Information Systems (GIS) forecast model to conduct an epidemiological analysis of human and animal fasciolosis in the central part of the Andes mountains. The GIS approach enabled us to develop a spatial and temporal epidemiological model to map the disease in the areas studied and to classify transmission risk into low, moderate and high risk areas so that areas requiring the implementation of control activities can be identified. Current results are available on a local scale for: (1) the northern Bolivian Altiplano, (2) Puno in the Peruvian Altiplano, (3) the Cajamarca and Mantaro Peruvian valleys, and (4) the Ecuadorian provinces of Azuay, Cotopaxi and Imbabura. Analysis of results demonstrated the validity of a forecast model that combines use of climatic data to calculate of forecast indices with remote sensing data, through the classification of Normalized Difference Vegetation Index (NDVI) maps.     

Assessment of airborne Asteraceae pollen in Brisbane, Australia

In the southern hemisphere, the airborne prevalence and seasonal distribution of Asteraceae pollen are poorly characterized. In this study, we assessed the longitudinal distribution of Asteraceae pollen using an historic aerobiological dataset. The influence of weather parameters on pollen derived from Asteraceae species was additionally explored. Asteraceae pollen was collected using a static Burkard 7-day spore trap during a 5-year (June 1994–May 1999) aerometric surveillance program in Brisbane, Australia. Two discrete seasonal intervals were identified each sampling year. The first interval (September and October) consisted of small quantities of unidentifiable Asteraceae pollen. The second interval (March and April) was characterized by the highest concentrations of Asteraceae pollen that were predominantly derived from Baccharis halimifolia. Associations between daily Asteraceae pollen concentrations and temperature were observed during each sampling year. The results of the study demonstrated that pollen derived from B. halimifolia, an invasive weed species introduced in the late nineteenth century, continue to be in the environment of Brisbane. Given the public health burden associated with personal Asteraceae pollen exposure in other geographic locations, future Australian-based clinical studies should characterize the contribution of Asteraceae pollen, in particular B. halimifolia, to allergic sensitization and respiratory morbidity.     

Revision of the rhinoceros beetle genus Oryctophileurus Kolbe with description of a new species,the male of O. varicosus Prell,and notes on biogeography (Scarabaeoidea,Dynastinae, Phileurini)

The genus Oryctophileurus is reviewed and its validity is supported by a combination of the following apomorphic characters: a single cephalic horn with lateral carina, pronotal cavity with ocellate punctures and two teeth or tubercles close behind the anterior pronotal margin. The male of Oryctophileurus varicosus Prell, 1934, is described for the first time. A new species, Oryctophileurus guerrai Perger & Grossi sp. n., from subhumid Tucuman-Bolivian forest in the Southern Bolivian Andes is described. The new species is distinguished from its closest relative, O. armicollis Prell, 1911, by a narrower distance between the inner teeth of the dorsal pronotal protuberances and a reduced area of weakly developed ocellate punctures above the posterolateral pronotal margin. The occurrence of Oryctophileurus species in areas of endemism along the eastern slope of the tropical Andes suggests that these populations represent biogeographic “relicts”, and the discovery of Oryctophileurus guerrai sp. n. in the southern Bolivian Andes suggests that this area is underrated with respect to insect diversity and endemism.     

Biogeographical analysis of rodent endemism and distributional congruence in the southern–central Andes (north‐western Argentina)

The recognition of areas of endemism (AEs) is important for conservation biology and biogeographical regionalization. Our objective was to quantitatively identify AEs and distributional congruence patterns of native rodents at the tropical/temperate transition in the central Andes. We analysed 6200 geo‐referenced distributional records of 80 species in north‐western Argentina using NDM/VNDM software. We found 20 AEs defined by 22 endemic species (27% of the total rodent fauna) and 34 patterns of distributional congruence in non‐endemic rodents. Geographical range congruence follows two main patterns running parallel along the Andes. One is related to the humid eastern slopes of the Andes (Argentinean Yungas forest) and the other to the high Andes (Argentinean Puna plateau). Endemism was mainly restricted to the southernmost part of the Yungas forest and adjacent dryer valleys (Monte desert). Species diversity was highest in the northern sector of the Argentinean Yungas forest, where several species reach their southern distributional range. This incongruence among hotspots of diversity and endemism has also been also noted in diversity studies at continental and global scales. Our results provide a starting point for conservation planning in the southernmost Central Andes, which combines the taper of tropical diversity and range‐restricted species endemic to the tropical–temperate transition. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 112 , 163–179.     

18,000 years of grassland evolution in the summer rainfall region of South Africa: evidence from Mahwaqa Mountain,KwaZulu-Natal

A palynological and sedimentological record from the Mahwaqa Mountain in KwaZulu-Natal, South Africa, provides evidence of the vegetation dynamics in this part of the Grassland Biome during the last c. 18,000 years. The wetland is located at 1,850 m on an isolated outlier of the Ukhahlamba–Drakensberg Mountain range on an ecotone along a climatic gradient. The vegetation responded to humidity and temperature changes during the late Pleistocene and Holocene. The period c. 18,000–13,500 cal. bp is characterized by high Ericaceae and Restionaceae percentages and decreasing values of charred particles, indicating cool conditions. Around 13,500–8,500 cal. bp, Ericaceae were gradually replaced by Poaceae, signaling climate warming. Growing environmental wetness during the same time period is inferred from Phragmites-type and Cliffortia pollen percentages. Since c. 8,500 cal. bp, Cliffortia, Restionaceae, and Phragmites-type percentages have maintained low levels. Ericaceae were almost completely replaced by grasses and Asteraceae by c. 7,500 cal. bp. All indications are that warm and fluctuating moisture conditions followed until 4,600 cal. bp but they became driest between c. 4,600 and 3,500 cal. bp, when high Asteraceae, Pentzia-type and Scabiosa percentages were prominent. From c. 3,500–800 cal. bp, the increase of sedges, Aponogeton and grass pollen (including Phragmites-type) at the expense of Asteraceae pollen suggests the return of slightly more humid conditions. Since c. 1,000 cal. bp an increase of water demanding Podocarpus and Cliffortia occurred. Pine pollen indicates the recent introduction of alien plants in the 19th and 20th centuries.