“Can you go back?” by Mark Bush – Part 1

September 17, 2019
WDG

Mark Bush

Mark Bush

This is the first in a special series of three guest blog posts by my friend, mentor and collaborator the tropical palaeoecologist and biogeographer Prof. Mark Bush (Florida Institute of Technology).

We are often told that you “cannot go back”, meaning that a place that provided wonderful memories will disappoint when revisited. Putting this into current conservation-speak we don’t like to be reminded that our baselines are shifting. Recently I had a chance to revisit a part of Ecuadorean Amazonia I had not been to for 30 years. I was a bit hesitant to go. Would I be disappointed or could the experience live up to my recollection?

In 1988, I went on a lengthy field season in Ecuador. We were searching for a glacial-age record that could test the refugial hypothesis of Amazonian speciation. Some lakes that lay in Ecuadorian Amazonia showed promise as they appeared to be a long way from major river channels, and only connected by their outlets into the Cuyabeno River. Would these lakes hold glacial-aged records? Would they show a history of rainforest or savanna during the last ice age?

We started from the frontier town of Lago Agrio, which was rough in every way, dirty, and somewhere we couldn’t wait to leave.  Driving to the end of the road and then picking up motorized canoes we were, by nightfall, able to get to the first tourist/research lodge to be established in what is now the Cuyabeno Faunistic Reserve. The trip there was basically uneventful, but a quick tour of the lake in our motorized dugout revealed a substantial inflowing river that had been hidden by cloud on the aerial imagery. We had been hoping for a headwater system, not an essentially riverine lake. Nevertheless, we cored the middle of the lake. The coring was tough as the river was washing clays into the system and these settled to form stiff, sticky, gray sediments. After one or two meters of coring, hammering was essential to get any penetration, but getting the core back out was the real challenge. The inflatable boats were sinking as we strained upward on the coring rig, but still we couldn’t break the device free from the clay. We tried everything: we clamped the boats to the coring rig when they were fully flooded, then bailed the boats out, hoping the added buoyancy would break the corer free. It didn’t. So we refilled the boats, re-clamped, bailed, and then all jumped out. Still nothing. In the end we resorted to the nuclear option, which is to hammer upward on the drill rig. The modified Livingstone coring rig we were using was designed to be hammered downward, but hammering upward can seriously damage the drill string. Nevertheless, it worked. Darkness was closing over us by the time we managed to free the rig, but already we knew that the core wasn’t the glacial-age record we had been hoping for. Faces in camp that evening were pretty glum. As the old axiom goes, we defined insanity by repeating the procedure in the next lake in the chain and, unsurprisingly, got the same outcome – another young core.

Victoriano, Haki, shaman and head of the Siona Nation in Cuyabeno. Photo: M. Bush.

Victoriano, Haki, shaman and head of the Siona Nation in Cuyabeno. Photo: M. Bush.

We resolved to move on and try another target system, Laguna Zancudococha. Our hosts and guides were members of the Siona nation, and their Hako (Chief) was a vibrant 82-year old called Victoriano. There was a long discussion deciding whether we could go to Zancudococha as it was their ‘origin’ lake and therefore sacred. Eventually, it was decided that we could go. The journey would take at least two days and although Victoriano knew the way, none of the others had been there before.

To be continued…

Typha as a wetland food resource: evidence from the Tianluoshan site, Lower Yangtze Region, China

June 3, 2019
WDG

Zhang, Y., van Geel, B., Gosling, W.D., Sun, G., Qin, L. & Wu, X. (2019) Typha as a wetland food resource: evidence from the Tianluoshan site, Lower Yangtze Region, China. Vegetation History and Archaeobotany. DOI: 10.1007/s00334-019-00735-4

Detecting the European arrival in the Caribbean

March 8, 2019
mickbonnen

The second of our discussion papers for the “Amsterdam Palaeoecology Club”:

Mick Bonnen

Mick ready to catch bumble bees!

Detecting the European arrival in the Caribbean
By Mick Bönnen (currently studying for MSc Biological Sciences, Ecology & Evolution track at the University of Amsterdam)

The paper we discussed was “Columbus’ footprint in Hispaniola: A paleoenvironmental record of indigenous and colonial impacts on the landscape of the central Cibao Valley, northern Dominican Republic” by Castilla-Beltrán et al (2018). The paper provides a multi-proxy paleoecological reconstruction of the Caribbean island nation of the Dominican Republic, spanning the last 1100 years. Personally I found this to be a very interesting paper, packed with information and interpretations on the impact of anthropogenic factors on past Caribbean environments. What this paper nicely demonstrates is the difference in impact between pre-colonial and post-colonial societies on the vegetation of the Dominican republic. Pre-colonial Hispaniola was inhabited by indigenous societies, the Taíno people, and while this paper clearly shows them having had an environmental impact in the form of fire management (e.g. for slash and burn agriculture), small scale deforestation and the introduction of cultivars such as maize and squash, their environmental impact remains modest compared to post-colonial disturbances. Columbus arriving in AD 1492 signified a moment of change in the landscape. The paleorecord suggests that, after an initial collapse of the Taíno population, the colonization of the Dominican Republic by the Spanish brought with it deforestation, crop monoculture and the introduction of European livestock, all of which still characterizes the landscape to this day.

The discussion mainly focused on the chronology used. One of the radiocarbon samples was excluded from the age-depth model for no apparent reason, which led us to discuss the importance of critically evaluating your calibrated radiocarbon dates and which ones to incorporate in your age-depth model. The age-depth model currently used implied a shift in pollen composition c. 30 years before the arrival of the Spanish. We were unsure how to interpret these findings because you would expect the shift to happen afterwards, so my initial thought was that it had to be a fault in the chronology. This chronology however does imply a large charcoal peak followed by a rapid decline that coincides precisely with the arrival of the Spanish, and it turned out that this was the reason the authors settled on this chronology.

Even though this paper by Castilla-Beltrán et al. didn’t spark any heated discussions, its incorporation of ecology, botany, history, archeology and geology still showcases the interdisciplinary nature of paleoecology, something I very much enjoy about this field of research.

References

Continue Reading

Central American climate and microrefugia: A view from the last interglacial

January 2, 2019
WDG

Cárdenes-Sandí, G.M., Shadik, C.R., Correa-Metrio, A., Gosling, W.D., Cheddadi, R. & Bush, M.B. (2019) Central American climate and microrefugia: A view from the last interglacial. Quaternary Science Reviews 205, 224-233. DOI: 10.1016/j.quascirev.2018.12.021

For free access click here before 19 February 2019

Job: Research Fellow in Palaeoecology (Amazonia)

October 30, 2018
WDG

University of St Andrews
School of Geography and Sustainable Development

Research Fellow in Palaeoecology (Amazonia) – AR2146HM
Working with: Dr. Ian Lawson and Dr. Katy Roucoux

Main purpose: Based at St Andrews, the PDRA will play an important role in a NERC-funded project working on the distribution and dynamics of peat-forming ecosystems in Amazonia. The post-holder will be required to undertake palaeoenvironmental research (including fieldwork, lab analyses, data analysis and write-up) in order to reconstruct the developmental history of the palm swamps, pole forests, and ‘open peatlands’ over the course of the Holocene. Some technical support for routine laboratory tasks will be available.

Deadline: 31 October 2018
For further information click here.

Past and future global transformation of terrestrial ecosystems under climate change

August 30, 2018
WDG

Nolan, C., Overpeck, J.T., Allen, J.R.M., Anderson, P.M., Betancourt, J.L., Binney, H.A., Brewer, S., Bush, M.B., Chase, B.M., Cheddadi, R., Djamali, M., Dodson, J., Edwards, M.E., Gosling, W.D., Haberle, S., Hotchkiss, S.C., Huntley, B., Ivory, S.J., Kershaw, A.P., Kim, S., Latorre, C., Leydet, M., Lézine, A., Liu, K., Liu, Y., Lozhkin, A.V., McGlone, M.S., Marchant, R.A., Momohara, A., Moreno, P.I., Müller, S., Otto-Bliesner, B.L., Shen, C., Stevenson, J., Takahara, H., Tarasov, P.E., Tipton, J., Vincens, A., Weng, C., Xu, Q., Zheng, Z. & Jackson, S.T. (2018) Past and future global transformation of terrestrial ecosystems under climate change. Science 361, 920-923. DOI: 10.1126/science.aan5360

Loughlin PhD Thesis 2018

July 25, 2018
nicholasloughlin

Nick recovers a sediment core for his PhD project.

Nick Loughlin

Loughlin, N.J.D. (2017) Changing human impact on the montane forests of the eastern Andean flank, Ecuador. PhD Thesis. School of Environment, Earth and Ecosystem Sciences, The Open University.

Abstract:

The montane cloud forests of South America are some of the most biodiverse habitats in the world, whilst also being especially vulnerable to climate change and human disturbance.

Today much of this landscape has been transformed into a mosaic of secondary forest and agricultural fields. This thesis uses palaeoecological proxies (pollen, non-pollen palynomorphs, charcoal, organic content) to interpret ecosystem dynamics during the late Quaternary, unravelling the vegetation history of the landscape and the relationship between people and the montane cloud forest of the eastern Andean flank of Ecuador. Two new sedimentary records are examined from the montane forest adjacent to the Río Cosanga (Vinillos) and in the Quijos Valley (Huila). These sites characterise the natural dynamics of a pre-human arrival montane forest and reveal how vegetation responded during historical changes in local human populations.

Non-pollen palynomorphs (NPPs) are employed in a novel approach to analyse a forest cover gradient across these sites. The analysis identifies a distinctive NPP assemblage connected to low forest cover and increased regional burning. Investigation into the late Pleistocene Vinillos sediments show volcanic activity to be the primary landscape-scale driver of ecosystem dynamics prior to human arrival, influencing montane forest populations but having little effect on vegetation composition.

Lake sediments at Huila from the last 700 years indicate the presence of pre-Hispanic peoples, managing and cultivating an open landscape. The subsequent colonization of the region by Europeans in the late 1500’s decimated the indigenous population, leading to the abandonment of the region in conjunction with an expansion in forest cover ca. 1588 CE. After approximately 130 years of vegetation recovery, montane cloud forest reached a stage of structural maturity comparable to that seen in the pre-human arrival forest. The following 100 years (1718-1822 CE) of low human population and minimal human impact in the region is proposed as a shifted ecological baseline for future restoration and conservation goals. This ‘cultural ecological baseline’ features a landscape that retains many of the ecosystem service provided by a pristine montane forest, while retaining the cultural history of its indigenous people within the vegetation. Continue Reading

BES Palaeoecology Special Interest Group

June 18, 2018
WDG

BES logoThe British Ecological Society is preparing for the launch of a new “Palaeoecology” Special Interest Group (SIG) at the Annual Meeting 2018 in Birmingham.

As part of the launch there will be a Thematic Session at the Birmingham meeting entitled Advancing our understanding of long-term ecology: combining ecological and palaeoecology approaches and metrics”and organised by Althea Davies and Ambroise Baker.

To find out how to get involved and join the SIG contact the organizers Althea Davies and/or Jane Bunting.

Job: Assistant/Associate Professor in Palaeoecology & Vegetation Dynamics

February 27, 2018
WDG

New Assistant/Associate Professor position advertised for the Palaeoecology group “down the road” at Utrect University.

Closing data: 31/03/2018
To find out more and apply click here.
Find out about Palaeoecology in Utrecht click here.

 

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