Fossil Pollen

A Late Messinian Palynoflora with a Distinct Taphonomy

by Fridgeir Grimsson

2011
Thomas Denk, Fridgeir Grimsson, Reinhard Zetter, Leifur A Simonarson
Springer
Chapter 9

Pollen, fruits, and leaves of Tetracentron (Trochodendraceae) from the Cainozoic of Iceland and western North America and their palaeobiogeographic implications

by Fridgeir Grimsson

2008
Fridgeir Grimsson, Thomas Denk, Reinhard Zetter
Grana

Episodic migration of oaks to Iceland: Evidence for a North Atlantic "land bridge" in the latest Miocene

by Fridgeir Grimsson

2010
Thomas Denk, Fridgeir Grimsson, Reinhard Zetter
American Journal of Botany

Diverse fossil Onagraceae pollen from a Miocene palynoflora of north-east China: early steps in resolving the phytogeographic history of the family

by Fridgeir Grimsson

2012
Fridgeir Grimsson, Reinhard Zetter, Qin Leng
Plant Systematics and Evolution

Combined LM and SEM study of the Middle Miocene (Sarmatian) palynoflora from the Lavanttal Basin: Part II. Pinophyta (Cupressaceae, Pinaceae and Sciadopityaceae)

by Fridgeir Grimsson

2011
Fridgeir Grimsson, Reinhard Zetter
Grana

Combined LM and SEM study of the Middle Miocene (Sarmatian) palynoflora from the Lavanttal Basin: Part I. Bryophyta, Lycopodiophyta, Pteridophyta, Ginkgophyta, and Gnetophyta

by Fridgeir Grimsson

2011
Fridgeir Grimsson, Reinhard Zetter, Christian Baal
Grana

Lythrum and Peplis from the Late Cretaceous and Cenozoic of North America and Eurasia: New evidence suggesting early diversification within the Lythraceae

by Fridgeir Grimsson

2011
Fridgeir Grimsson, Reinhard Zetter, Christa-Charlotte Hofmann
American Journal of Botany

A 17 000‐year history of Andean climate and vegetation change from Laguna de Chochos, Peru

by William Gosling

Bush, M.B., Hansen, B.C.S., Rodbell, D., Seltzer, G.O., Young, K.R., León, B., Silman, M.R. and Gosling, W.D. (2005). A 17,000-year history of Andean climatic and vegetation change from Laguna de Chochos, Peru. Journal of Quaternary Science, 20 (7-8): 703-714.

The manifestation of major climatic events such as the timing of deglaciation and whether, or not, the Younger Dryas... more The manifestation of major climatic events such as the timing of deglaciation and whether, or not, the Younger Dryas affected Andean systems has garnered considerable recent attention. Even the Holocene is rapidly emerging as a time of considerable interest in Neotropical palaeoclimatology and palaeoecology. The Holocene of the Neotropics is now revealed as a time of some temperature change with precipitation:evaporation ratios fluctuating markedly. Major changes in lake level, ice-accumulation, and vegetation are indicative of changes both in precipitation and temperature regimes. Although global-scale forcing mechanisms may underlie some of these changes, e.g. the precessional rhythm, other variability appears to be localised. In a record from near the upper forest limit of the eastern Peruvian Andes, pollen, charcoal, and sedimentary data suggest that the deglaciational period from ca. 17 000 to ca. 11 500 cal. yr BP was a period of rapid climatic oscillations, set against an overall trend of warming. A warm-dry event is evident between ca. 9500 and ca. 7300 cal. yr BP, and comparisons with other regional archives suggest that it was regional in scale. A ca. 1500-yr periodicity in the magnetic susceptibility data is evident between 12 000 and 6000 cal. yr BP, reaching a peak intensity during the dry event. A weaker oscillation with a 500–600-yr periodicity is present throughout much of the Holocene. The uppermost sample of the pollen analysis reveals deforestation as modern human land use simplified the landscape.

Holocene fire and occupation in Amazonia: records from two lake districts

by William Gosling

Bush, M.B., Silman, M.R., de Toledo, M.B., Listopad, C., Gosling, W.D., Williams, C., de Oliveira, P.E. and Krisel, C. (2007). Holocene fire and occupation in Amazonia: records from two lake districts. Philosophical Transactions of the Royal Society B, 362: 209-218.

While large-scale pre-Columbian human occupation and ecological disturbance have been demonstrated close to major... more While large-scale pre-Columbian human occupation and ecological disturbance have been demonstrated close to major Amazonian waterways, less is known of sites in terra firme settings. Palaeoecological analyses of two lake districts in central and western Amazonia reveal long histories of occupation and land use. At both locations, human activity was centred on one of the lakes, while the others were either lightly used or unused. These analyses indicate that the scale of human impacts in these terra firme settings is localized and probably strongly influenced by the presence of a permanent open-water body. Evidence is found of forest clearance and cultivation of maize and manioc. These data are directly relevant to the resilience of Amazonian conservation, as they do not support the contention that all of Amazonia is a ‘built landscape’ and therefore a product of past human land use.

Glacial-interglacial changes in moisture balance and the impact on vegetation in the southern hemisphere tropical Andes (Bolivia/Peru)

by William Gosling

Gosling, W.D., Bush, M.B., Hanselman, J.A. and Chepstow-Lusty, A. (2008) Glacial-interglacial changes in moisture balance and the impact on vegetation in the sourthern hemisphere tropical Andes. Palaeogeography, Palaeoclimatology, Palaeoecology 259 (1): 35-50.

A palynological investigation of the last glacial-interglacial cycle in the southern hemisphere tropical Andes reveals... more A palynological investigation of the last glacial-interglacial cycle in the southern hemisphere tropical Andes reveals changes in the moisture balance as the main driver in vegetation change. Thirty accelerator mass spectrometry radiocarbon dates, biostratigraphy and tephra correlation reveal that a 119 m sediment core recovered from the Huiñaimarca sub-basin of Lake Titicaca (16.0° to 17.5° S, 68.5° to 70° W; 3810 masl) contains sediments covering > 151,000 years. Correlation of aridity indicators with precessional variations in insolation is used to fine tune the structure of the age-depth curve within this period.

Variations in Isoëtes concentration (above/below 10,000 grains/cm3) identify the extent of shallow water environments. Examination of another palaeolimnological indicator (Pediastrum) and consideration of the bathymetry of the Huiñaimarca sub-basin allow the reconstruction of lake-level fluctuations. These data indicate five wet/dry cycles between c. 151,000 and 14,200 cal yr BP. High stands are suggested during the transition into (c. 134,000 cal yr BP), and out of (c. 114,000 and 92,000 cal yr BP), the last interglacial, and during full glacial conditions (c. 70,000 and 45,000 cal yr BP). These cycles are superimposed on a general trend of deepening lake levels through the glacial period.

This interpretation is supported by correlation with sediments from Salar de Uyuni (20°S, 68°W; 3653 masl). The youngest wet episode is concurrent with palaeolake Minchin (c. 45,000 cal yr BP), with further evidence for an additional wet period commencing c. 28,000 cal yr BP, concomitant with palaeolake Tauca. The timing of lake level fluctuations is also supported by palaeoshoreline reconstructions from the Uyuni-Poopó region. However, our data do not suggest a major peak in lake level in Huiñaimarca during the Ouki lake cycle (c. 120,000–98,000 cal yr BP) as inferred from U–Th ages obtained from palaeoshorelines around Lago Poopó. The most extreme dry event occurs during the last interglacial period and resulted in a sedimentary hiatus tentatively dated to c. 121,000–129,000 cal yr BP.

The observed wet/dry cycles are shown to have a marked and rapid impact on the vegetation. The aridity of the last interglacial promoted a community dominated by Chenopodiaceae/Amaranthacae, with no modern Andean analogue. Polylepis/Acaena pollen is also shown to fluctuate markedly (0–20%), particularly during the transitions into, and out of, the last interglacial. It is probable that this pollen taxon is primarily representative of the high altitude arboreal genus Polylepis, which is a key component of highly biodiverse Andean woodlands today. Rapid fluctuations indicate the sensitivity of this ecosystem to natural environmental pressure and potential vulnerability to future human impact and climate change.

The 100,000 year (eccentricity) solar cycle is shown to be the major controlling factor in moisture balance and vegetation over the last glacial-interglacial cycle. However, significant fluctuations in moisture balance are also evident on timescales considerably shorter than the full glacial-interglacial cycle. We have linked these to precessional (21,000 year) forcing. Nevertheless, precise independent dating during the full glacial cycle is required to confirm the importance of this forcing mechanism.

Long‐term drivers of change in Polylepis woodland distribution in the central Andes

by William Gosling

Gosling, W.D., Hanselman, J.A., Knox, C., Valencia, B.G., & Bush, M.B. (2009) Long term drivers of change in Polylepis woodland distribution in the central Andes. Journal of Vegetation Science, 20(6), 1041-1052.

Question: Is the modern patchy distribution of highly biodiverse Polylepis woodlands a consequence of human activity... more Question: Is the modern patchy distribution of highly biodiverse Polylepis woodlands a consequence of human activity or, natural fluctuations in environmental conditions? What are the consequences of changing climate for the tree genus Polylepis?

Location: High central tropical Andes.

Methods: We characterise the ecological baseline conditions for Polylepis woodlands over the last ca. 370,000 years through: i) examination of fossil pollen records (Salar de Uyuni and Lake Titicaca) and, ii) a review of autecological information concerning Polylepis.

Results: Fossil pollen data reveal fluctuations in the abundance (c. 0-34%) of Polylepis pollen prior to the arrival of humans in South America (>12,000 years ago). Indicating that Polylepis did not form permanent continuous woodland prior to the arrival of humans and that climatic factors can drive rapid vegetation change. Autecological assessment of Polylepis reveals: i) negative moisture balance, ii) fire, iii) waterlogging, and iv) cloud cover to be critical to determining the niche space available for Polylepis.

Conclusions: Polylepis niche space in the central Andes was at a maximum during warm and wet conditions in the past, but might be at a minimum during the warmer and drier-than-modern conditions predicted for later this century. The sensitivity to past global climate change emphasises the need for conservation planners to consider model predictions of a warmer central Andes in the coming decades when developing planting schemes. Natural fluctuations in woodland abundance suggest the most effective way for conservation efforts to 'mimic' the natural baseline would be to develop a reproductively connected patchwork of communities.

Nonlinear climate change and Andean feedbacks: an imminent turning point?

by William Gosling

Bush, M.B., Hanselman, J.A. and Gosling, W.D. (2010). Non-linear climate change and Andean feedbacks: An imminent turning point? Global Change Biology, 16(12), 3223-3232.

A 370 000-year paleoecological record from Lake Titicaca provides a detailed record of past climate change in which... more A 370 000-year paleoecological record from Lake Titicaca provides a detailed record of past climate change in which interglacial periods are seen to have some elements of commonality, but also some key differences. We advance a conceptual feedback model to account for the observed changes that includes previously ignored lake effects. Today Lake Titicaca serves to warm the local environment by about 4–5 °C and also to increase rainfall. We observe that as water levels in the lake are drawn down due to warm, dry, interglacial conditions, there is a possible regional cooling as the lake effect on local microclimates diminishes. Positive feedback mechanisms promote drying until much of the lake basin is reduced to salt marsh. Consequently, the usual concept of upslope migration of species with warming would not be applicable in the Altiplano. If, as projected, the next century brings warmer and drier conditions than those of today, a tipping point appears to exist within ca. 1–2 °C of current temperatures, where the relatively benign agricultural conditions of the northern Altiplano would be replaced by inhospitable arid climates. Such a change would have profound implications for the citizens of the Bolivian capital, La Paz.

A 370,000-year record of vegetation and fire history around Lake Titicaca (Bolivia/Peru)

by William Gosling

Hanselman, J.A., Bush, M.B., Gosling, W.D., Collins, A., Knox, C., Baker, P.A. & Fritz, S.C. (2011) A 370,000-year record of vegetation and fire history around Lake Titicaca (Bolivia/Peru) Palaeogeography, Palaeoclimatology, Palaeoecology, 305: 201-214.

Fossil pollen and charcoal analyses of sediments from Lake Titicaca, Peru/Bolivia, provide a record of palaeoclimatic... more Fossil pollen and charcoal analyses of sediments from Lake Titicaca, Peru/Bolivia, provide a record of palaeoclimatic variation spanning four full glacial cycles. Pollen, aquatic microfossils, and charcoal, as well as previously published data including diatom assemblages, carbonate content, and stable carbon isotopic ratios of organic carbon, indicate that interglacials were warm and dry whereas the peaks of glacials were cold and wet. Each of the interglacials documented in the record are somewhat different, with those of MIS 5e and MIS 9 inducing lower lake levels and a drier vegetation signature than those of MIS 7 and 1. The presence of charcoal particles in sediments deposited during previous interglacials provides evidence of the long-term role of fire in shaping Andean ecosystems.

Contrasting pollen histories of MIS 5e and the Holocene from Lake Titicaca (Bolivia/Peru)

by William Gosling

Hanselman, J.E., Gosling, W.D., Ralph, G.M. and Bush, M.B. (2005). Contrasting histories of MIS 5e and the Holocene from Lake Titicaca (Bolivia/Peru). Journal of Quaternary Science, 20 (7-8): 663-670.

Two long sediment records (cores LTO1-2B and LT01-3B) from Lake Titicaca, Bolivia/Peru, are compared with a previously... more Two long sediment records (cores LTO1-2B and LT01-3B) from Lake Titicaca, Bolivia/Peru, are compared with a previously analysed Holocene record from this lake (core NE98-1PC). The Holocene records of LT01-2B and NE98-1PC are similar. There are striking differences, however, between the MIS 5e sections of the long cores and the Holocene records. In these records, temperature is probably the dominant parameter that determines the total fossil pollen concentration and is used to time the onset and termination of deglaciation. In contrast, the relative and absolute abundance of specific taxa (e.g. Polylepis/Acaena, Chenopodiaceae) are indicators of relative moisture availability. Although the Holocene contains a period of aridity between ca. 8000 cal. yr BP and 4300 cal. yr BP, it is a minor event compared with the more extreme aridity of MIS 5e. Core LT01-3B showed similar trends during MIS 5e when compared to LT01-2B, as did NE98-1PC when comparing Holocene records. MIS 5e and the Holocene are markedly different interglacials, depicted by shifts in pollen concentration and taxa representation over time.

A simple and effective methodology for sampling modern pollen rain in tropical environments

by William Gosling

Gosling, W.D., Mayle, F.E., Killeen, T.J., Siles, M., Sanchez, L. and Boreham, S. (2003). A simple and effective methodology for sampling modern pollen rain in tropical environments. The Holocene 13(4): 613-618.

To gain a better insight into the nature of palaeovegetation change in tropical ecosystems, more information needs to... more To gain a better insight into the nature of palaeovegetation change in tropical ecosystems, more information needs to be gleaned from the limited number of fossil pollen records that exist. To achieve this, a detailed understanding of modern tropical ecosystems and the pollen they produce is required. To facilitate this, a practicable and effective mechanism for sampling modern pollen rain from the tropics is required. This paper presents a modified field methodology based upon three years of trapping experience in Noel Kempff Mercado National Park, Bolivia, and improved laboratory preparation methodologies. We demonstrate here a simple and very effective way to sample modern pollen rain in tropical environments using a funnel trap mounted on a stake containing cotton fibre as the trapping medium.

Vegetation, climate and fire in the eastern Andes (Bolivia) during the last 18,000 years

by William Gosling

Williams, J.J., Gosling, W.D., Brooks, S.J., Coe, A.L. & Xu, S. (2011) Vegetation, climate and fire in the eastern Andes (Bolivia) during the last 18,000 years Palaeogeography, Palaeoclimatology, Palaeoecology, 312(1-2): 115-126. http://dx.doi.org/doi:10.1016/j.palaeo.2011.10.001

A c. 18 ka cal BP long sediment record from Laguna Khomer Kocha Upper (4153 m asl), Bolivia, shows that fire regime,... more A c. 18 ka cal BP long sediment record from Laguna Khomer Kocha Upper (4153 m asl), Bolivia, shows that fire regime, governed by climatic variation, has long been a transformative agent in the eastern Andes. Before c. 14.5 ka cal BP, warming and relatively moist conditions free from fire, facilitated the expansion of high Andean Polylepis woodland. Fire onset at c. 14.5.ka cal BP, quickly transformed the local vegetation and the woodlands became restricted to areas protected from fire. A major increase in burning, c. 10.1–6.4 ka cal BP removed Polylepis woodland locally and this coincided with a region-wide Holocene dry event (HDE) which caused falling lake levels and allowed fire intensification. A decline in burning at c. 6.4 ka cal BP and an increase in marsh–woodland (Alnus) marked the termination of the HDE and a return to wetter conditions. As well as recording the environmental history of local vegetation dynamics, long-distance pollen transport provides evidence of changes in the Yungas montane forests, highlighting their sensitivity to climate and burning regimes. Simultaneous adjustments in both Andean and Yungas montane taxa suggest that vegetation dynamics in the two environments are linked to a common climatic driver. There is no evidence to indicate that human activity had any impact on the local landscape.

Highlights
► Fossil pollen, charcoal and spores provided an 18 ka year record of climate change. ► Charcoal revealed that fire was a transformative agent in the eastern Andes. ► A major increase in burning occurred in the early Holocene (10.1 ka cal BP). ► Pollen and charcoal indicated a shift to wetter conditions at 6.4 ka cal BP. ► The sensitivity of Polylepis woodland to fire is confirmed.

Arctic plant diversity in the Early Eocene greenhouse

by Guy Harrington

Proceedings of the Royal Society B

For the majority of the early Cenozoic, a remarkable expanse of humid, mesothermal to temperate forests spread across... more For the majority of the early Cenozoic, a remarkable expanse of humid, mesothermal to temperate forests spread across northern Polar regions that now contain specialised plant and animal communities adapted to life in extreme environments. Little is known on the taxonomic diversity of Arctic floras during greenhouse periods of the Cenozoic. We show for the first time that plant richness in the globally warm early Eocene (approx. 55-52 Ma) in the Canadian High Arctic (76°N) is comparable to that approximately 3500 Km further south at mid latitudes in the US Western Interior (44-47°N). Arctic Eocene pollen floras are most comparable in richness to today’s forests in the south-eastern United States, some 5000 km further south of the Arctic. Nearly half of the Eocene, Arctic plant taxa are endemic and the richness of pollen floras implies significant patchiness to the vegetation type and clear regional richness of angiosperms. The reduced latitudinal diversity gradient in early Eocene North American plant species demonstrates that extreme photoperiod in the Arctic did not limit taxonomic diversity of plants.

Miospores from upper Cretaceous-Paleocene strata in northwestern Bolivia

by Vivi Vajda

Vajda-Santivanez: Palynology (1999): 23, 181-196.

Outcrop samples from the Flora and Eslabón formations from northwestern Bolivia contain abundant terrestrial... more Outcrop samples from the Flora and Eslabón formations from northwestern Bolivia contain abundant terrestrial palynomorphs. Pollen grains and spores of 49 species belonging to 36 genera were identified and two new pollen species –Psilaperiporites boliviensis and Psilaperiporites suarezi -are described. The Bolivian palynoflora consists mainly of monocolpate, tricolpate and tricolporate angiosperm pollen grains. The gymnosperm pollen content is low and bisaccates are totally lacking. Some samples also include fungal spores and the fresh-water algae Botryococcus. The assemblage from the Eslabón Formation is compared with that of the Proreacidites dehaani Zone, known
from Colombia and Venezuela, and with that of the Tricornites elongatus Zone in Brazil, indicating late Maastrichtian age. The palynoflora of the Flora Formation is probably of Paleocene age. The results indicate deposition in a continental warm and humid environment, as suggested by the composition of the palynoflora which show an abundance of palm pollen grains and the presence of Botryococcus and Azolla megaspores.

Vegetation, climate and fire in the eastern Andes (Bolivia) during the last 18,000 years

by Joseph Williams

Joseph J Williams, William D Gosling, Stephen J Brooks, Angela L Coe and Sheng Xu. 2011, Palaeogeography, Palaeoclimatology, Palaeoecology. 312(1-2). pp.115-126.

A c. 18 ka cal BP long sediment record from Laguna Khomer Kocha Upper (4153 m asl), Bolivia, shows that fire regime,... more A c. 18 ka cal BP long sediment record from Laguna Khomer Kocha Upper (4153 m asl), Bolivia, shows that fire regime, governed by climatic variation, has long been a transformative agent in the eastern Andes. Before c. 14.5 ka cal BP, warming and relatively moist conditions free from fire, facilitated the expansion of high Andean Polylepis woodland. Fire onset at c. 14.5.ka cal BP, quickly transformed the local vegetation and the woodlands became restricted to areas protected from fire. A major increase in burning, c. 10.1 − 6.4 ka cal BP removed Polylepis woodland locally and this coincided with a region-wide Holocene dry event (HDE) which caused falling lake levels and allowed fire intensification. A decline in burning at c. 6.4 ka cal BP and an increase in marsh-woodland (Alnus) marked the termination of the HDE and a return to wetter conditions. As well as recording the environmental history of local vegetation dynamics, long-distance pollen transport provides evidence of changes in the Yungas montane forests, highlighting their sensitivity to climate and burning regimes. Simultaneous adjustments in both Andean and Yungas montane taxa suggests that vegetation dynamics in the two environments are linked to a common climatic driver. There is no evidence to indicate that human activity had any impact on the local landscape.

Highlights
► Fossil pollen, charcoal and spores provided an 18 ka year record of climate change. ► Charcoal revealed that fire was a transformative agent in the eastern Andes. ► A major increase in burning occurred in the early Holocene (10.1 ka cal BP). ► Pollen and charcoal indicated a shift to wetter conditions at 6.4 ka cal BP. ► The sensitivity of Polylepis woodland to fire is confirmed.

Keywords: Fossil pollen; Fossil charcoal; Deglaciation; Holocene dry event (HDE); Polylepis woodland; Temperature; Precipitation

The response of vegetation on the Andean flank in western Amazonia to Pleistocene climate change

by William Gosling

Cárdenas, M.L., Gosling, W.D., Sherlock, S.C., Poole, I., Pennington, R.T. & Mothes, P. (2011) The response of vegetation on the Andean flank in western Amazonia to Pleistocene climate change. Science, 331, 1055-1058.

A reconstruction of past environmental change from Ecuador reveals the response of lower montane forest on the Andean... more A reconstruction of past environmental change from Ecuador reveals the response of lower montane forest on the Andean flank in western Amazonia to glacial-interglacial global climate change. Radiometric dating of volcanic ash indicates that deposition occurred ~324,000 to 193,000 years ago during parts of Marine Isotope Stages 9, 7, and 6. Fossil pollen and wood preserved within organic sediments suggest that the composition of the forest altered radically in response to glacial-interglacial climate change. The presence of Podocarpus macrofossils ~1000 meters below the lower limit of their modern distribution indicates a relative cooling of at least 5°C during glacials and persistence of wet conditions. Interglacial deposits contain thermophilic palms suggesting warm and wet climates. Hence, global temperature change can radically alter vegetation communities and biodiversity in this region.