August 2015 – Ambroise Baker's Research

New paper: Pollen productivity from the old-growth forest of Białowieża differs from that of cultural landscapes across Europe

Baker, A.G., Zimny, M., Keczyński, A., Bhagwat, S.A., Willis, K.J., Latałowa, M. (2016) Pollen productivity estimates from old-growth forest strongly differ from those obtained in cultural landscapes: Evidence from the Białowieża National Park, Poland. The Holocene 26, 80-92. http://hol.sagepub.com/content/26/1/80

Available online: 29 July 2015

Pollen productivity estimates of individual plant species are necessary when determining changes of vegetation cover in the past using fossil pollen. To date, studies describing pollen productivity in lowland temperate Europe have been carried out in cultural landscapes showing low forest cover and dominated by human activities. However, these may be of limited use when applied to reconstruct past land cover, for instance, from pre-agricultural landscapes.

The aim of this paper was to ascertain whether pollen productivity from the closed canopy old-growth forest in the Białowieża National Park, Poland, where human impact has been minimal for nearly a century, is different from that calculated in much more open landscapes. We asked: how much does forest antiquity and structure influence the amount of pollen released from particular taxa?

Our results demonstrate that pollen from forest grasses and forest hazel is six times more under-represented in old-growth forest than that estimated from cultural landscapes. This finding reinforces the idea that pollen productivity can vary in response to changes in the prevailing environmental setting and we present for the first time a quantification of this variability, likely induced by differences in light availability.

The Forest of Białowieża is a flagship ecosystem in European nature conservation. It covers about 1450 km2 straddling the border between Poland and Belarus. Białowieża is the largest expanse of lowland temperate closed canopy forest in Europe and it is unique for the complete assemblage of native trees, large herbivores and carnivores, for its size and for its antiquity.

Sobering thoughts from Baltimore, 100th annual meeting of the Ecological Society of America

The 100^th ESA annual meeting was a great experience! It was an opportunity to present our work, of course, but what I really enjoyed was the breadth and depth. The breadth of ecological topics represented was exceptional – speak about biodiversity!- and the depth of the talks and of the understanding within each subfield was phenomenal.

I would like to highlight three researchers and their talks. There were many other remarkable ones but these actually tie well together in what I would call a list obstacles for our societies to deal effectively with the biodiversity crisis and with ecological issues in general.

Stephen Jackson from the University of Arizona, USA, presented five major challenges for ecology. Among those, three could be labelled as governance challenges within ecological research – whether within academic institutions or in the way academics interacts with decision makers and land managers.

Two others were more directly related to our science. Stephen notably put an emphasis on the difficulties related to defining nature in a context of ever-changing conditions – and in a context of omnipresent human pressure.

This last point was further developed by Jens-Christian Svenning from Aarhus University, Denmark. It was divided into three categories: disequilibrium dynamics, novel ecosystems and trophic cascade. These three ecological phenomena remind us how much ecosystem function in a complex way. As a result of this complexity, ecosystems have futures that are extremely difficult, if not impossible, to predict.

Jens-Christian presented several compelling examples to illustrate his talk and I would refer anyone interested to his publication list.

Finally, Shannon Hagerman, from the University of British Columbia, Canada, provided a wider framework explaining the origin of these institutional and ecological challenges.

Shannon’s work focusses on the values underlying expert opinion in biodiversity science and claims that today’s novel impact created by human activities not only threatens biodiversity in a direct way (as we all understand it) but it also deeply questions the values that have hitherto guided conservation actions.

It can be postulated that this crisis of values within the field of conservation at large creates obstacles for us to deal effectively with the biodiversity crisis itself and with ecological issues in general.

This is a very simplified synthesis of these three talks, that certainly does not do them justice, and the opinions expressed are mine. Ambroise, Sheffield, UK, August 27th 2015

Senecio inaequidens, narrow-leaved ragwort, Kirk Sandall station, South Yorkshire, UK

I got familiar with this species on the continent, where it became very abundant but seeing it near Doncaster on the railway tracks was quite a surprise – I had not seen it for quite a while now: it was like meeting up with a good old friend!

Senecio inaequidens, the narrow-leaved ragwort, is a fast spreading plants from Southern Africa that is mainly found in ruderal situations in Europe. It’s identification is relatively easy because it has the flowers of a ragwort (well, no wonder as it is one…) but it has very narrow leaves without any lobes (see picture below) and it has a stout fibrous stem. Keep your eyes peeled as it is likely to be under-recorded!

Transport networks such as railway and roads are often vector of spreading species. This is not only because vehicles transport seeds and other propagules but also because the transport network creates continuous novel habitats whose physical and disturbance conditions can strongly differ from the surrounding landscape.

Cystopteris fragilis, brittle bladder-fern, Multangular Tower, York city centre, UK

Yet another interesting urban plant. I found Cystopteris fragilis, the brittle bladder-fern, thriving on old walls in the city of York. It is possible that improved air quality in the recent decades and a drastic reduction of acid rains is increasingly favouring this species and other alkaline-substrate-loving ferns such as Ceterach officinarum – rustyback – to grow on mortar in urban situations.