Wednesday, 23 March 2011

Pollen from Moxos

The group of Quaternary palaeoecology – University of Edinburgh – has recently published a paper on the Review of Palaeobotany and Palynology. The paper, “Characterisation of Bolivian savanna ecosystems by their modern pollen rain and implications for fossil pollen records” addresses an important question: how well do pollen assemblages represent the composition of the vegetation in Beni's seasonally flooded savannah? Answering this question is a pre-condition to the correct interpretation of the fossil pollen records.
Imagine you have a lake surrounded by grass and the forest is 10 km away. If you measure the pollen (using pollen traps) in the grassland right by the lake shore, you will get almost only grass pollen. And what type of pollen would you expect to find in the middle of the lake? As the lake is surrounded by grassland, the obvious answer would be grass pollen…but, Jones et al. have actually found a lot of forest pollen. The reason is that the travel distance of pollen depends on the reproductive strategies of each kind of vegetation. If a tree relies on wind for spreading its pollen, that pollen will travel a long distance from the tree. On the contrary, plants that rely on more complex strategies for pollination, like using insects, will be under-represented in the lake. Understanding these pollen/vegetation relations is key to the correct interpretation of the pollen records in lacustrine sediments.
I think, and hope, that quite soon we will see a paleo-environmental reconstruction of the Llanos de Moxos based on pollen record from lakes around Trinidad. I am very curious to see whether we are able to differentiate those changes in the pollen profile caused by natural events from man-induced changes in the last 2500 years


  1. ... and still more curious to see WHICH of those many lakes will provide those 3000 years (or more???) of continuous lake sediment: no sediment = no pollen! mi opinion ya lo conocen (desde hace años)...

  2. However....
    they do not take into account the seasonal floods. I think that the mixing of the lake water with the flood water is a major factor in the final pollen assemblage. It could also explain the "regional" signal in the lake water, maybe even better than the different pollinating strategies.