New paper: Quantification of large herbivore populations… using dung fungal spores

Baker et al. (2016) Quantification of population sizes of large herbivores and their long-term functional role in ecosystems using dung fungal spores. Methods in Ecology and Evolution. http://dx.doi.org/10.1111/2041-210X.12580

Article first published online: 12 MAY 2016

You’ll be interested in our latest paper developing the dung fungal spore method and published in Methods in Ecology and Evolution.

With this paper and our 2013 review (see this post), my co-authors and I open the path for improved quantitative reconstruction of large herbivore population sizes. These quantitative reconstructions will be critical for any future research to contribute to topical themes such as rewilding, megafauna and ecosystem function.

Most of the research examining the relationship between large herbivores and their impact on landscapes has used extant studies. An alternative approach is to estimate the impact of variations in herbivore populations through time using fossil dung fungal spores and pollen in sedimentary sequences. The ponds at Oostvaardersplassen provided the ideal setting  to develop further the dung fungal spore method and determine the relationship between spore abundance in sediments and herbivore biomass densities. Our results indicate that this method provides a robust quantitative measure of herbivore population size over time.

The Oostvaardersplassen, The Netherlands, is a nature reserve established on polder land. Re-wilding was initiated at this site from 1983 with the introduction of free-ranging Heck cattle (Bos taurus Linnaeus) in 1983, Konik horses (Equus ferus caballus Linnaeus) in 1984 and red deer (Cervus elaphus Linnaeus) in 1992. Moreover, 1001 ponds were created throughout the reserve between 1985 and 2000 for avian biodiversity. The site is managed with a policy of minimal intervention, i.e. the population size of freely roaming large herbivores is not controlled by culling, no supplementary feeding is given during winter and no management intervention is implemented to maintain vegetation.

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New paper: Phytolith analysis reveals the intensity of past land use change in the Western Ghats biodiversity hotspot.

Nogué, S., Whicher, K., Baker, A.G., Bhagwat, S.A. & Willis, K.J. (2016) Phytolith analysis reveals the intensity of past land use change in the Western Ghats biodiversity hotspot. Quaternary International.

Article first published online: 8 March 2016.

 

Second post-doc on freshwater biodiversity

From January 1st 2016, I will start working as a post-doctoral researcher on the newly funded project Hydroscape, one of NERC’s highlight topics.

Hydroscape is led by Dr Nigel Willby at the University of Stirling and is interested in the importance of interactions between connectivity and stressors for freshwater biodiversity.

From   https://hydroscapeblog.wordpress.com/about/   :

“Hydroscape is a four-year project that started in December 2015 and is funded by the UK Natural Environment Research Council (NERC). It aims to determine how stressors and connectivity interact to influence biodiversity and ecosystem function in freshwaters across Britain. While stressors such as nutrient pollution and climate change drive ecological degradation, connectivity between freshwater habitats is a major force behind both dispersal of stressors and biodiversity. Currently, the implication for freshwaters of future changes in stressor intensity and in connectivity levels across Britain are poorly understood. Hydroscape will significantly improve this understanding and therefore inform the work of organisations engaged in waterbody restoration, biological conservation, the control of invasive species and diseases of wildlife and humans, at the international, national and local level.”

My main focus within Hydroscape will be on the “Distribution of biodiveristy within the landscape” and how connectivity affects biodiversity distibution, connectivity being a measure of potential for dispersal.

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.

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New Paper: Looking forward through the past: identification of 50 priority research questions in palaeoecology

Seddon A.W.R., Mackay A.W., Baker, A.G., et al. (66 other authors) (2014) Looking forward through the past. Identification of fifty priority research questions in palaeoecology. Journal of Ecology. 102, 256–267. Link.

Article first published online: 16 December 2013

This multi author, horizon-scanning paper presents the 50 priority questions in palaeoecology that were identified during a workshop that Alistair, Anson and I organised in December 2012 in Oxford.

PhD Thesis abstract, final version after revisions, February 2014

Tree cover in the early Holocene in temperate Europe and implications for the practice of re-wilding in nature conservation

This thesis addresses the methodological challenges of determining the variability of large herbivore populations through time and their impact on European vegetation.

Large herbivores are at the heart of conservation policy however, opinions widely diverge on whether we should aim for fewer herbivores and managed populations or, on the contrary (as advocated by the rewilding movement) more herbivores and self-regulating populations acting as ecosystem engineers. This controversy has roots in a debate regarding the nature of ecosystems before the prevalence of human activities. Baseline ecosystems are either described as continuous forest cover with passive large herbivores, or, in contrast, as mosaics with patchy forest cover driven inter alia by bison, aurochs and horses, now rare or extinct in Europe. The main obstacle in moving this debate forward is a poor understanding of large-herbivore densities in the past.

I analysed modern pollen and spore assemblages from known environmental settings to improve palaeoecological interpretation of fossil assemblages dating from the pre-human (baseline) period. The sites investigated are the rewilded grasslands of the Oostvaardersplassen (The Netherlands), the mosaic habitats of The New Forest (UK) and the old-growth closed-canopy forest of Białowieża (Poland).

I demonstrate that the common practice of interpreting pollen percentages fails to estimate past forest cover in situations with natural grazing. As an explanation, I suggest that pollen productivity fluctuates with biotic factors such as herbivory and canopy shading. As a result, new insights into the baseline debate require additional lines of evidence. In this thesis, I develop an existing methodology to reconstruct past herbivore presence using fossil dung fungal spores. I synthesise current knowledge of this method with an emphasis on spore identification and, finally, I demonstrate that dung fungal spore abundance in lake sediments can be translated into large herbivore numbers.

The evidence presented in this thesis contributes to the debate on re-wilding and addresses a fundamental challenge of nature conservation in the human-dominated landscapes of Europe.