Loughlin, N.J.D., Gosling, W.D., Coe, A.L., Gulliver, P., Mothes, P. & Montoya, E. (2017) Landscape-scale drivers of glacial ecosystem change in the montane forests of the eastern Andean flank, Ecuador. Palaeogeography, Palaeoclimatology, Palaeoecology. DOI: 10.1016/j.palaeo.2017.10.011
I am delighted to report that I have recently been appointed as an Associate Editor for the journal Vegetation History & Archaeobotany (VHA). The journals scope is global and covers Quaternary environmental and climatic change, with a specific focus on the Holocene and pre-historic human impacts on landscapes; often linking palaeoecological and archaeological research. My remit with VHA is to provide expertise on tropical, and in particular South American, studies. Recent articles in VHA with a South American focus include:
Assessing the influence of glacial-interglacial climate changes on the dry forest vegetation along the southern edge of Amazonia (Whitney et al., 2014),
I hope that over the next few years we can publish some more exciting articles on the tropics in VHA and I would therefore like to encourage you to submit interesting high quality original research, reviews, or short articles for our consideration.
To find out more about the journal and submit an article click here.
Flantua, S.G.A., Hooghiemstra, H., Grimm, E.C., Behling, H., Bush, M.B., González-Arango, C., Gosling, W.D., Ledru, M., Lozano-García, S., Maldonado, A., Prieto, A.R., Rull, V. & Van Boxel, J.H. Updated site compilation of the Latin American Pollen Database. Review of Palaeobotany and Palynology 223, 104-115. DOI: 10.1016/j.revpalbo.2015.09.008
Clement, C.R., Denevan, W.M., Heckenberger, M.J., Junqueira, A.B., Neves, E.G., Teixeira, W.G. & Woods, W.I. (2015) The domestication of Amazonia before European conquest. Proceedings of the Royal Society of London B: Biological Sciences 282. DOI: 10.1098/rspb.2015.0813
Oliver, T.H., Heard, M.S., Isaac, N.J.B., Roy, D.B., Procter, D., Eigenbrod, F., Freckleton, R., Hector, A., Orme, C.D., Petchey, O.L., Proenca, V., Raffaelli, D., Suttle, K.B., Mace, G.M., Martin-Lopez, B., Woodcock, B.A. & Bullock, J.M. Biodiversity and Resilience of Ecosystem Functions. Trends in Ecology & Evolution. DOI: 10.1016/j.tree.2015.08.009
Watkins, C. (2015) Oliver Rackham OBE FBA 1939–2015. Landscape History 36, 5-8. DOI: 10.1080/01433768.2015.1044280
COMMENT: One of the books that inspired me to enter this field of research was Rackham’s Trees and woodlands in the British landscape; published the year I was born…
Bush, M.B. (1995) Neotropical plant reproductive strategies and fossil pollen representation. American Naturalist 145, 594-609. Stable URL: http://www.jstor.org/stable/2462970
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. DOI: 10.1126/science.1197947
Logan, A.L. & D’Andrea, A.C. (2012) Oil palm, arboriculture, and changing subsistence practices during Kintampo times (3600–3200 BP, Ghana). Quaternary International 249, 63-71. DOI: 10.1016/j.quaint.2010.12.004
Heslop-Harrison, J. (1979) Aspects of the structure, cytochemistry and germination of the pollen of Rye (Secale cereale L.). Annals of Botany, 44, 1-47.
Summary (Adele): Sometimes, the old ones are the best, and this behemoth of a paper contains a huge amount of useful information on the chemical structure and development of Rye pollen grains. As I am working on the chemistry of grass pollen at the moment, it is incredibly useful to know that this sort of information exists and can be used to inform both my experimental protocol and interpretations.
Cárdenas, M.L. (2011) The response of western Amazonian vegetation to fire and climate change: A palaeoecological study. PhD Thesis, Department of Earth & Environmental Sciences, The Open University.
MLC Ecuador (2008)
Amazonia is one of the most biodiverse regions of the world, a reputation largely earned by the floristic richness of western Amazonia, namely the Ecuadorian Andes. In particular, montane cloud forest in western Amazonia on the Andean flank has been identified as of high ecological value because of its large floristic diversity. Unfortunately, montane forests’ biodiversity have suffered a strong detrimental impact due the ongoing human activity and climate change. Consequently, understanding the dynamics of montane forest and identifying the main factors that control them is fundamental to manage and protect these ecosystems.
This thesis focuses upon paleoecological data obtained from organic sediments from Erazo (Ecuador), located today within the lower montane forest. Examination of modern vegetation and pollen rain close to Erazo revealed florist variation at the kilometer scale related to human disturbance. Modern data provided the basis for interpreting the fossil record. Radiometric dating of interbedded volcanic ash indicates the sediments were deposited c. 324,000-193,000 years ago, well before the arrival of humans in America. Fossil pollen and wood preserved within organic sediments suggest that the composition of the forest was different to modern and changed significantly during the middle Pleistocene. Taxonomic changes in the fossil pollen assemblage, coupled with the presence of Podocarpus spp. macrofossils within the sediments, indicate that temperatures reached c. 5oC cooler than modern. Given the timing and magnitude of vegetation cha
nge observed in the Erazo sediments it therefore seems likely that the variations were instigated by global temperature changes associated with Marine Isotope Stage (MIS) 9 and the MIS 7-6 transition from interglacial-glacial conditions.
The palaeoecological data from Erazo indicate that far from being a relatively stable ‘museums’ tropical forests are in fact dynamic systems undergoing long term floristic re-assortment as well as being susceptible to abrupt short term floristic reorganization.
SUMMARY (Will): People have long been concerned about environmental change. Observations of phenological shifts, degradation of ecosystem services and climate change are clearly presented in Checkhov’s “The Pipe” (1889).The key difference is today we have a better idea of why these things are happening!?
Garcia, R.A., Cabeza, M., Rahbek, C. & Araújo, M.B. (2014) Multiple dimensions of climate change and their implications for biodiversity. Science 344 1247579
SUMMARY (Phil): This review highlights the alternative metrics used to quantify climate change at different spatial scales, each with its own set of threats and opportunities for biodiversity. It’s a very relevant paper for palaeoecologists, with implications for how we think about climatic estimates we generate, how we interpret ecological shifts in the assemblages we study, and for demonstrating the importance thinking spatially as well as temporally. It also shows how important palaeoecological data is for setting baselines and putting projected climatic change into context.
Stansell, N.D., Polissar, P.J., Abbott, M.B., Bezada, M., Steinmann, B.A. and Braun, C. (2014) Proglacial lake sediment records reveal Holocene climate changes in the Venezuelan Andes. Quaternary Science Reviews. 89, 44 – 55.
SUMMARY (Hayley): A study of three lake sediment records in the Venezuelan Andes to look at patterns of glacial variability, and how glaciers might have responded to changing climatic conditions during the last c. 12,000 years.
Still, C.J., Foster, P.N. & Schneider, S.H. (1999) Simulating the effects of climate change on tropical montane cloud forests. Nature, 398, 608–610.
SUMMARY (Nick): The paper attempts to model the impact of climate change on a number of cloud forests around the world by simulating atmospheric parameters at the last glacial maximum (LGM) and at twice today’s CO2 level. The models agrees with palaeoecological data of a downslope migration of the cloud forest at the LGM, while the 2xCO2 model shows reduced cloud cover and increased evapotranspiration, which results in a significant reduction in cloud forest supporting land area.
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.
EM Venezuela (2007)
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.