The ACER pollen and charcoal database: a global resource to document vegetation and fire response to abrupt climate changes during the last glacial period

October 11, 2017
WDG

Goni, M.F.S., Desprat, S., Daniau, A., Bassinot, F.C., Polanco-Martinez, J.M., Harrison, S.P., Allen, J.R.M., Anderson, R.S., Behling, H., Bonnefille, R., Burjachs, F., Carrion, J.S., Cheddadi, R., Clark, J.S., Combourieu-Nebout, N., Mustaphi, C.J.C., Debusk, G.H., Dupont, L.M., Finch, J.M., Fletcher, W.J., Giardini, M., Gonzalez, C., Gosling, W.D., Grigg, L.D., Grimm, E.C., Hayashi, R., Helmens, K., Heusser, L.E., Hill, T., Hope, G., Huntley, B., Igarashi, Y., Irino, T., Jacobs, B., Jimenez-Moreno, G., Kawai, S., Kershaw, A.P., Kumon, F., Lawson, I.T., Ledru, M., Lezine, A., Liew, P.M., Magri, D., Marchant, R., Margari, V., Mayle, F.E., McKenzie, G.M., Moss, P., Mueller, S., Mueller, U.C., Naughton, F., Newnham, R.M., Oba, T., Perez-Obiol, R., Pini, R., Ravazzi, C., Roucoux, K.H., Rucina, S.M., Scott, L., Takahara, H., Tzedakis, P.C., Urrego, D.H., van Geel, B., Valencia, B.G., Vandergoes, M.J., Vincens, A., Whitlock, C.L., Willard, D.A. & Yamamoto, M. (2017) The ACER pollen and charcoal database: a global resource to document vegetation and fire response to abrupt climate changes during the last glacial period. Earth System Science Data 9, 679-695. DOI: 10.5194/essd-9-679-2017

Shanahan, T.M., Hughen, K.A., McKay, N.P., Overpeck, J.T., Scholz, C.A., Gosling, W.D., Miller, C.S., Peck, J.A., King, J.W. & Heil, C.W. (2016) CO2 and fire influence tropical ecosystem stability in response to climate change. Scientific Reports 6, 29587. DOI: 10.1038/srep29587

Lahr, M.M. et al. (2016) Inter-group violence among early Holocene hunter-gatherers of West Turkana, Kenya. Nature 529, 394-398. doi: 10.1038/nature16477

Rademaker, K., Hodgins, G., Moore, K., Zarrillo, S., Miller, C., Bromley, G.R.M., Leach, P., Reid, D.A., Yepez Alvarez, W. & Sandweiss, D.H. (2014) Paleoindian settlement of the high-altitude Peruvian Andes. Science 346, 466-469. doi: 10.1126/science.1258260

da Silva, S.G. & Tehrani, J.J. (2016) Comparative phylogenetic analyses uncover the ancient roots of Indo-European folktales. Royal Society Open Science 3. doi

Veenendaal, E.M. et al. (2015) Structural, physiognomic and above-ground biomass variation in savanna-forest transition zones on three continents – how different are co-occurring savanna and forest formations? Biogeosciences 12, 2927-2951. doi: 10.5194/bg-12-2927-2015

Netherlands Annual Ecology Meeting 2016 – day 2

February 10, 2016
WDG

NAEM_0Netherlands Annual Ecology Meeting (NAEM) 2016
10 February 2016
Conference Centre “De Werelt”, Lunteren

Day 2 of the NAEM breakfast 07:30, first lectures at 08:30… Two keynotes today thinking about ecological stoichiometry the first by Stan Harpole (Martin-Luther-Universitat-Halle-Wittenberg) focused on resource ratio theory, and then Martin Wassen (Utrecht University) thinking about N and P limitations. I also attended, parts of, three sessions today “Linkages between fire, vegetation, soil and ecosystem services”“Novel ecosystems”, and “Scaling from trait to environment and back”. My top talks for today were:

  1. Elmar Veenendaal (Wageningen University) Fire effects on tropical woody vegetation structure have been exaggerated?
    Working on long-term fire study plots (Kokondekro since 1932) suggest that for forest-savannah transition zones fire alone is insufficient to mediate a change between states; human manipulation of ecosystems is required as well to trigger the change.
  2. Frank van Langevelde (Wageningen University) Feedbacks between fire and patches of woody vegetation in tropical grassland savannah
    Examination of tree distributions and fire within the Kruger National Park shows that landscapes contain more clustered tree populations when fire frequency is higher.

Plus today I have done lots of talking and made many new contacts. I have lots of follow up emails to write and promised papers to send around! Overall this has been a super meeting for meeting people – perfect for expanding my network of Dutch based ecologists – in a nice location, with good food and beer. Looking forward to next year already.

Paleontologia: Cenários de Vida – Paleoclimas Volume 5Bush, M.B., de Oliveira, P.E., Raczka, M.F., Gosling, W.D., Mayle, F.E., McMichael, C.H. & Urrego, D.H. (2014) Paleoclimates of Amazonia: An ice-age view. IN: Ribeiro F. & Carvalho, I. (eds.) Paleontologia: Cenários de Vida – Paleoclimas Volume 5. Editora Interciência Ltda., Brazil, pp. 353-368. ISBN: 9788571933439

Williams PhD thesis 2011

May 13, 2014
WDG

Williams, J.J. (2011) Human and climate impacts on tropical Andean ecosystems. PhD Thesis, Department of Earth & Environmental Sciences, The Open University.

JJW Bolivia (2007)

JJW Bolivia (2007)

Abstract:

Population growth and predicted global climate change are applying new, and increasing, pressure to mountain environments, but the consequences of these changes upon the biodiverse and vulnerable Tropical Andean ecosystems are poorly understood. This thesis explores past human-climate-ecosystem interactions using multi-proxy palaeolimnological investigations (fossil pollen, spore, charcoal and Chironomidae (midges); elemental abundance, colour spectra and magnetic susceptibility) of two sites in the eastern Bolivian Andes (Lake Challacaba and Laguna Khomer Kocha Upper) over the last c. 18,000 years. During the deglaciation and Holocene ecosystems were exposed to varying climatic stress levels, and pressures imposed by the development of human cultures.

Examination of preserved ecological assemblages, including the first assessment of subfossil central Andean Chironomidae, reveals ecosystem sensitivity to changes in temperature, moisture, fire regime, lake level and salinity. Charcoal analysis from Laguna Khomer Kotcha Upper reveals changes in burning at c. 14,500, 10,100 and 6,400 cal yr BP. Concomitant palynological shifts shows this climatically controlled fire regime was a transformative agent of Andean vegetation, particularly for the threatened, high elevation, Polylepis woodlands. Pollen and geochemical data from Lake Challacaba indicate two periods of aridity (c. 4000−3370 and 2190−1020 cal yr BP), these broadly correlated to El Niño/Southern Oscillation variations. Increased Sporormiella abundance after c. 1,340 cal yr BP indicate changes in trade routes and agricultural practices; demonstrating human adaption to environmental change and interconnectivity to Tiwanaku and Inca civilizations.

The long-term response of the terrestrial and aquatic ecosystems, reconstructed from these lakes, has provided insights into how Tropical Andean ecosystems may respond to future changes in temperature, precipitation and human interference. The palaeoenvironmental data has implications for conservation management; it indicates that spatial and temporal variations in site sensitivity, exposure and resilience should be assessed, and that planting strategies should mimic the present day natural patchy distribution of Polylepis woodlands.

Supervisors: Dr. William D. Gosling , Dr. Angela Coe (both The Open University), and Steve Brooks (Natural History Museum).

Examined by: Prof. Henry Hoogheimstra (University of Amsterdam), and Prof. Bob Spicer (The Open University).

To borrow a copy from The Open University Library click here.

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Montoya PhD thesis 2011

May 8, 2014
encarnimontoya

Montoya, E. (2011) Paleocology of the southern Gran Sabana (SE Venezuela) since the Late Glacial to the present. PhD Thesis, Department of Animal Biology, Plant Biology and Ecology, Unitersitat Autonoma de Barcelona.

Encarni_07

EM Venezuela (2007)

Abstract:

This thesis is aimed to study the paleoecology of the southern Gran Sabana region (GS; SE Venezuela) since the Late Glacial to the present. This region is characterized nowadays by the occurrence of large extent of savannas in a climate suitable for rainforests. For this purpose, three sequences (two from peat bogs and one from lake sediments) have been analyzed for pollen and spores, non-pollen palynomorphs (NPP), and microscopic charcoal particles. Among the sequences analyzed, two of them are located currently within treeless savannas (Lakes Chonita and Encantada); whereas the third one is placed in the boundary between GS savannas and Amazon forests (El Paují). The Late Glacial interval of Lake Chonita was characterized by a shrubland that was replaced by a treeless savanna at the end of Younger Dryas (YD) and the onset of the Holocene, linked to the occurrence of regional fires since ca. 12.4 cal kyr BP. The beginning of local fires was dated synchronous with the vegetation replacement, ca. 11.7 cal kyr BP. A similar shrubland, though not identical, is located nowadays around 200 m elevation above the lake, so the replacement by surrounding savannas was interpreted as a probably upward displacement of the former vegetation and an increase in average temperatures of approximately 0.7 ‐1.5ºC. This section represents the oldest interval analyzed for GS so far, and the presence of fires during the Late Pleistocene is among the oldest fire records documented for northern South America. The peat bog records of Lake Encantada and El Paují showed the main vegetation trends of the last 8 cal kyr BP, which were characterized by the continuous occurrence of regional fires. In Lake Encantada, the presence of treeless savannas was reported during the whole interval analyzed as the dominant vegetation type, despite variations in forest abundance and composition taxa of the community also occurred. The vegetation changes in this record were interpreted as mainly due to climatic shifts until the Late Holocene. At El Paují, the occurrence of forests and savanna/forest mosaics was reported during the same interval, and fire was postulated to have been the major driver of the vegetation shifts. In this sequence, a treeless savanna was not recorded as the dominant vegetation of the landscape until the last millennia, and the presence of two different indigenous cultures was postulated as responsible of the shifts in fire regime registered, with an interval of human land abandonment between them. This interval was characterized by the cessation of fires, and the establishment of a secondary dry forest. The Late Holocene was characterized, in the three sequences studied, by a sudden increase of fires, which likely favored the expansion of savannas and the establishment of the present GS landscape.

The join interpretation of the records presented in this thesis, together with previous analyses in the region, highlighted some key aspects for understanding the main trends of GS landscape and vegetation, e.g., the appearance and establishment of morichales (Mauritia palm stands typical of current southern GS landscapes) has been restricted to the last two millennia, synchronous with the increase in fire incidence. Moreover, it has been possible to gather empirical evidence for testing some previous hypothesis regarding GS. For example, the proposal of an extended aridity prior the Holocene has been rejected, whereas the hypothesis about the postglacial expansion of morichales has been supported. In this sense, with all the available information to date, some suggestions have been proposed: (i) Climate and fire have been the major forcing factors operating in the GS; (ii) During the Late Glacial and the beginning of the Early Holocene, the landscape of southern GS was likely formed by a mosaic of forests, shrubs, and savannas, without the current supremacy of the last vegetation type, which only established during the last 2 cal kyr BP onwards; (iii) Some general climatic trends have been inferred for the study area, as for example an increase in average temperatures around the Late Glacial/Early Holocene transition, a dry interval from 8 to 5 cal kyr BP, and a wetter phase during the Mid-Holocene centered around 4 cal kyr BP; (iv) The establishment of Mauritia in the region has been likely driven by a synergism between biogeographical, climatic and anthropogenic factors, as well as the likely pyrophilous nature of this palm given its synchronous appearance with the increase of fires; (v) The settlement of the modern indigenous culture (Pemón) occurred at least since around ca. 2000 cal yr BP onwards, 1500 yr earlier than previously thought, but previous human presence in the region has been also documented; and (vi) The fire activity observed in the long-term has caused a huge impact on GS landscape.

Supervisor: Dr Valenti Rull (Botanic Institute of Barcelona); Tutor: Dr Iñigo G. de la Cerda (Universitat Autonoma de Barcelona)

Examined by: Prof. Jose S. Carrion (Univesity of Murcia), Dr Toby Pennington (Royal Botanic Garden of Ediburgh), Prof. Francisco LLoret (Autonomous University of Barcelona), Dr Fred Stauffer, (Conservatoire et Jardin botaniques Ville de Geneve), and Dr Walter Finsinger (CNRS).

To access to this thesis PF file from the library service of the Autonomous University of Barcelona, please click here.

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Highlights of articles members of the group read recently.

Newspaper articles:

The natural historian faces extinction: Overspecialism and funding cuts could end a vital scientific tradition, claim experts by Joe Kavanagh in The Independent

Fires could turn Amazon rainforest into a desert as human activity and climate change threaten ‘lungs of the world’, says study by Steve Connor in The Independent.

Linked to this article:

Scientific papers:

Giesecke, T., Ammann, B. and Brande, A. (2014) Palynological richness and evenness: insights from the taxa accumulation curve. Vegetation history and archaeobotany. 32, 217 – 228.

SUMMARY (Hayley): “A new method is presented on splitting the log – transformed taxa accumulation curve into sections (natural breaks where the curve deviates from a linear trend), with the hypothesis that breaks in the curve could indicate shifts in abundance between high (e.g. wind pollinated taxa) and low producers of pollen (e.g. insect pollinated taxa), this hypothesis is tested on pollen diagrams from three separate pollen diagrams from varying landscapes.”

Katifori, E., Alben, S., Cerda, E., Nelson, D.R. & Dumais, J. (2010) Foldable structures and the natural design of pollen grains. Proceedings of the National Academy of Sciences of the United States of America, 107, 7635-7639.

SUMMARY (Adele): “This elegant paper highlights the changeability of pollen grains and their responses to their environment, giving those of us who identify pollen based on morphological characteristics plenty to think about.”

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