EcolChange seminar – Silvia Lotman about everyman´s right to care about nature

Seminars of Department of Botany and Centre of Excellence EcolChange

Speaker: Silvia Lotman is nature conservation expert and chairman of the board of the Estonian Fund for Nature (ELF). She studied in the Department of Botany, University of Tartu, and is now also the head of the species conservation program at ELF and leader of the LIFE project “NaturallyEST”.

Title of the talk: Estonian Fund for Nature and everyones’ nature conservation

Time: Thursday, 5. March 2020 at 14.15

Place: Tartu, Lai 40-218 (Vaga auditorium)

Summary: Silvia will give an overview of Estonian Fund for Natures’ strategic plan for nature conservation and the past, current and future plans for citizen science and everyones´ nature conservation projects.

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Rights and obligations – everyman´s trade-off (pic from here)

 

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New publication – Population-level performance of Arabidopsis thaliana (L.) Heynh in dense monocultures

Text and pics by Susanna Vain

The tiny weedy species Arabidopsis thaliana can teach us quite a bit about agriculture, even though the species itself is not agriculturally important. Arabidopsis has played an immense role in helping us understand the molecular and/or genetic mechanisms behind plant functioning. Many such parallels have also been found in crops, hence the importance of Arabidopsis for agriculture.[1] In this particular study we were interested in using Arabidopsis to study competition on a population-level and its effects on seed yield, which is also something that could help us advance agriculture.

Plant breeding so far has focused on individual performance of plants, i.e. the best-performing individuals are selected. Farmers, however, do not pick out the best individuals, they are interested in the yield from the whole field where there are tens of thousands of plants, all growing and interacting together. This has brought discussion to alternatives – perhaps plant breeding should use group selection in which not best individuals but best groups are selected for further trials.[2] This method centers around the collective performance of plants and puts much greater emphasis on plant-plant interactions. Still, there are great gaps in our knowledge about plant-plant interactions, especially on a population-level scale.

Susanna arabidopsis 01

In this paper, the effect of plant density in two different photoperiod conditions was studied to learn how it affects the collective performance of plants. Plants were sown at five densities (17.6, 8.8, 4.4, 2.2 and 1.1 cm2 per plant) and grown either in 16 h or 12 h day length conditions. What is also relatively novel about the methodology of this experiment was that instead of small pots, quite large trays were used (44×25 cm). This ensured truer monoculture conditions – one sown population constituted minimum of 64 plants in the sparsest and 1000 plants in the densest treatment.

Surprisingly, populations across all sowing densities attained constant seed yield, which was greater for plants that grew in 16 h photoperiod treatment. This means that regardless of whether there were 64 plants, 500 or 1000 plants in a tray within a photoperiod treatment, all populations produced the same amount of seeds. Furthermore, no main effect of photoperiod treatment was found for vegetative biomass production. So, seemingly, differences in biotic and abiotic conditions did not trigger competitive responses which is usually indicated by differential biomass production (and that could have led to reduced yield as well).

Susanna arabidopsis 02

Did plants just make use of resources available to them, not minding their co-competitors at all? Not quite. Even though we found no evidence of differential vegetative biomass production, closer inspection revealed a sowing density and photoperiod treatment interaction for the average mass of 100 seeds. Plants that grew sparsely, produced seeds of similar weights in both photoperiod conditions. When sowing density was increased, the weight of individual seeds diverged in opposite directions – the average seed produced in 16 h conditions was heavier than that produced in 12 h photoperiod conditions. So, instead of varying vegetative biomass production, plants’ focus seemed to be on the seeds, which is not unexpected since Arabidopsis is a species with relatively short life-cycle (approx. 6 weeks).

In conclusion, this study showed that vegetative biomass and total seed yield are not the only things to consider when assessing the performance of plants. When plants produce the same amount of vegetative or generative biomass, then this does not automatically mean that plants have no reactions to different conditions at all. There is still a lot to be learned.

Susanna arabidopsis 03

Citation: Vain, S., Gielen, I., Liira, J., & Zobel, K. (2020). Population-level performance of Arabidopsis thaliana (L.) Heynh in dense monocultures. Journal of Plant Ecology, rtaa006, https://doi.org/10.1093/jpe/rtaa006 (link to full text)

Abstract:

AIMS

Very little is known about the performance of non-agricultural plant species in monocultures, even though nearly all agricultural species have experienced the transition from multi-species environments to dense monospecific stands during the breeding process. In the light of recent work that highlighted the possibility that the weedy species Arabidopsis thaliana can offer novel insight into crop breeding, we aimed to test the effect of sowing density on group and individual performance in different photoperiod environments in A. thaliana.

METHODS

We studied the performance of A. thaliana Cvi-0 ecotype. The choice of Cvi-0 was based on a preliminary experiment in which plants of Cvi-0 ecotype exhibited high competitive performance. Sowing densities used were 17.6, 8.8, 4.4, 2.2 and 1.1 cm2 per plant and photoperiod environments 12 h or 16 h of day light.

IMPORTANT FINDINGS

In this experiment, populations attained constant total seed yield for all densities. Some interaction effect occurred, as at high sowing density and at longer day length plants produced heavier seeds, whereas at shorter day length seed weight was negatively related to plant density. These results shed light on different strategies that annual plants can adopt when they face intense intraspecific competition, and could help to offer new perspectives for breeding crops with enhanced group performance.

 

 

[1] Gonzalez, N., Beemster, G. T., & Inzé, D. (2009). David and Goliath: What can the tiny weed Arabidopsis teach us to improve biomass production in crops? Current Opinion in Plant Biology, 12(2), 157–164. https://doi.org/10.1016/j.pbi.2008.11.003
[2] Weiner, J., Andersen, S. B., Wille, W. K.-M., Griepentrog, H. W., & Olsen, J. M. (2010). Evolutionary Agroecology: The potential for cooperative, high density, weed-suppressing cereals. Evolutionary Applications, 3(5–6), 473–479. https://doi.org/10.1111/j.1752-4571.2010.00144.x
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EcolChange seminar – Aurèle Toussaint about traits on global scale

Seminars of Department of Botany and Centre of Excellence EcolChange

Speaker: Aurèle Toussaint is a research fellow in the Macroecology group at the University of Tartu. He is working on the functional diversity and its vulnerability in a context of biodiversity crisis. Using databases of traits for more than 80,000 species across five taxonomic groups (plants, mammals, birds, reptiles, amphibians, and freshwater fishes), he will show how the loss of vulnerable species will affect the functional diversity globally and across biogeographical realm.

Title of the talk: Global functional spectra of plants and vertebrates

Time: Thursday, 27. February 2020 at 14.15

Place: Tartu, Lai 40-218 (Vaga auditorium)

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EcolChange seminar – Jonne Kotta about climate change, human impacts and marine ecosystems

Seminars of Department of Botany and Centre of Excellence EcolChange

Speaker: Jonne Kotta is research director of the Estonian Marine Institute, University of Tartu. His research focuses on ecological investigations of marine biodiversity in benthic habitats in the Baltic Sea and the Gulf of Finland.

Title of the talk: Climate change, human impacts and marine ecosystems

Time: Thursday, 20. February 2020 at 14.15

Place: Tartu, Lai 40-218 (Vaga auditorium)

Summary: Marine ecosystems are often assumed to be highly vulnerable to ongoing climate change and introduction of exotic species. Although these stressors are completely different they both increase the risk of disrupting the pathways of energy flow through native ecosystems and result notable shifts in structure and function. The current lack of understanding of ecosystem interaction cascades, however, underscores the need for more basic exploratory research. Here I present a real data and modelling evidence from Arctic, Antarctic marine ecosystems and the Baltic Sea to show sensitivities of different environments to these global stressors. Incorporating ecosystem changes from climate change and exotic species is an important task of maritime spatial planning and marine resource management. We recently developed an online decision support tools capable of linking big data and modelling cumulative impacts of multiple stressors. Such scientific resources have huge unused potential as they can help decision-makers to select efficient mitigation actions in order to achieve environmental and socio-economic sustainability.

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EcolChange seminar – Teppo Rämä about Arctic marine fungi

Seminars of Department of Botany and Centre of Excellence EcolChange

Speaker: Teppo Rämä is a mycologist working with Arctic marine fungi since 2010. He took his PhD on the diversity and ecology of driftwood-associated fungi at University of Tromsø – The Arctic University Norway (UoT) in 2014. Since 2015, he is working with biodiscovery of antibacterial molecules from Arctic marine fungi and recently started in a tenure-track Associate Professor position in marine microbiomes at UoT.

Title of the talk: Arctic marine fungi, their ecology and potential for biotechnological applications

Time: Monday, 17. February 2020 at 12.15

Place: Tartu, Ravila 14A, Chemicum (auditorium 1019)

 

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New publication – Global gene flow releases invasive plants from environmental constraints on genetic diversity

Text originally posted in University of Queensland (link)

Plants that break some of the ‘rules’ of ecology by adapting in unconventional ways may have a higher chance of surviving climate change, according to researchers from the University of Queensland and Trinity College Dublin.

Dr Annabel Smith, from UQ’s School of Agriculture and Food Sciences, and Professor Yvonne Buckley, from UQ’s School of Biological Sciences and Trinity College Dublin Ireland, studied the humble plantain (Plantago lanceolate) to see how it became one of the world’s most successfully distributed plant species.

“The plantain, a small plant native to Europe, has spread wildly across the globe – we needed to know why it’s been so incredibly successful, even in hot, dry climates,” Dr Smith said.

The global team of 48 ecologists set up 53 monitoring sites in 21 countries, tagged thousands of individual plants, tracked plant deaths and new seedlings, counted flowers and seeds and looked at DNA to see how many individual plants have historically been introduced outside Europe.

What they discovered went against existing tenets of ecological science.

“We were a bit shocked to find that some of the ‘rules of ecology’ simply didn’t apply to this species,” Dr Smith said.

“Ecologists use different theories to understand how nature works – developed and tested over decades with field research – these are the so-called ‘rules’.

“One of these theories describes how genetic diversity or variation in genes embedded in DNA are produced by changes in population size.

“Small populations tend to have little genetic diversity, while large populations with many offspring, such as those with lots of seeds, have more genetic diversity.

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Plantago lanceolata (pic from here)

“Genetic diversity sounds boring, but actually it’s the raw material on which evolution acts; more genetic diversity means plants are better able to adapt to environmental changes, like climate change.

“We discovered that, in their native range, the environment determined their levels of genetic diversity.

“But, in new environments, these rule breakers were adapting better than most other plants.”

The team found the plantain’s success was due to multiple introductions around the world.

Professor Buckley, who coordinates the global project from Trinity College Dublin Ireland, said the DNA analysis revealed that ongoing introductions into Australia, NZ, North America, Japan and South Africa quickly prompted genetic diversity,

It gave these ‘expats’ a higher capacity for adaptation,” Professor Buckley said.

“In Europe plantains played by the rules, but by breaking it outside of Europe, it didn’t matter what kind of environment they were living in, the plantains almost always had high genetic diversity and high adaptability.”

Dr Smith said the finding was fascinating and critical, for two crucial reasons.

“It’s important we now know that multiple introductions will mix genetic stock and make invasive plants more successful quite quickly – an important finding given invasive species cause extinction and cost governments billions of dollars,” she said.

“And secondly, research on invasive plants gives us clues about how our native plants might adapt to climate change.


There are three participating sites from Estonia, all related to Ecolchange, and managed by Aveliina Helm, Meelis Pärtel, and Lauri Laanisto.

 

Reference: Smith, A., Hodkinson, TR., Villellas, J., … Helm, A., Pärtel, M., Laanisto, L., … Buckley, Y. (2020). Global gene flow releases invasive plants from environmental constraints on genetic diversity. Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.1915848117 (link to full text)

 

Abstract:

When plants establish outside their native range, their ability to adapt to the new environment is influenced by both demography and dispersal. However, the relative importance of these two factors is poorly understood. To quantify the influence of demography and dispersal on patterns of genetic diversity underlying adaptation, we used data from a globally distributed demographic research network comprising 35 native and 18 nonnative populations of Plantago lanceolata. Species-specific simulation experiments showed that dispersal would dilute demographic influences on genetic diversity at local scales. Populations in the native European range had strong spatial genetic structure associated with geographic distance and precipitation seasonality. In contrast, nonnative populations had weaker spatial genetic structure that was not associated with environmental gradients but with higher within-population genetic diversity. Our findings show that dispersal caused by repeated, long-distance, human-mediated introductions has allowed invasive plant populations to overcome environmental constraints on genetic diversity, even without strong demographic changes. The impact of invasive plants may, therefore, increase with repeated introductions, highlighting the need to constrain future introductions of species even if they already exist in an area.

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EcolChange seminar – Sabrina Träger about landscape-scale genetics of Primula

Seminars of Department of Botany and Centre of Excellence EcolChange

Speaker: Dr. Sabrina Träger is a post-doctoral fellow at the Department of Botany, University of Tartu. Her research focuses on landscape genetics of grassland plant species.

Title of the talk: Landscape genetic analysis of Primula veris in Estonian alvar grasslands

Time: Thursday, 13. February 2020 at 14.15

Place: Tartu, Lai 40-218 (Vaga auditorium)

Summary: Fragmentation of semi-natural habitats due to management changes is one of the major threats to genetic diversity. Recent high-throughput genotyping enables the detection of numerous genetic markers distributed over the whole genome, including regions of adaptive relevance. Here, I will present results of a landscape genetic investigation of Primula veris populations in Estonian alvar grasslands to estimate the effect of habitat deterioration on the genetic diversity and adaptive potential of this valuable grassland species.

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Cowslip aka Primula (pic from here)

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Ecolchange seminar – Ivika Ostonen and Biplabi Bhattara talk about grassland warming

Seminar of Department of Geography, UT and Centre of Excellence EcolChange

Speakers: Ivika Ostonen is a senior researcher, and Biplabi Bhattarai is PhD student in the Department of Geography, University of Tartu.

Titles of the talks: “Subarctic grassland ecosystem’s response to warming (by Ivika) and “Functional adaptation of root-rhizobiome in warming grassland” (by Biplabi)

Time: Wednesday, 29. January 2019 at 16.00

Place: Tartu, Vanemuise 46-327 (JG Granö auditorium)

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It´s warming alright… We have plants flowering in Estonia in January, which is unprecedented. (pic from here)

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EcolChange seminar – Mander, Pärn & Kasak reflecting about AGU2020 meeting

Seminar of Department of Geography, UT and Centre of Excellence EcolChange

Speakers: Ülo Mander, Jaan Pärn and Kuno Kasak all work at the Department of Geography, University of Tartu.

Title of the talk: AGU 2020 – Experiences, Insights and New Trends in Earth Sciences Around the Globe

Time: Wednesday, 18. December 2019 at 16.00

Place: Tartu, Vanemuise 46-327 (JG Granö auditorium)

 

 

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New paper – Predictability of leaf morphological traits for paleoecological reconstruction: the case of leaf cuticle and leaf dry mass per area

Text by Linda-Liisa Veromann-Jürgenson and Tiina Tosens

We just published a paper about the plausibility of using cuticle thickness in gymnosperms as a proxy for leaf mass per dry area (LMA). It was as the result of a wonderful collaboration between six academic institutes from four countries. The paper titled “Predictability of leaf morphological traits for paleoecological reconstruction: the case of leaf cuticle and leaf dry mass per area” is one of the two papers representing our team in the International Journal of Plant Sciences special issue – Functional Trait Evolution.

The reasoning behind this paper was to test a paleoproxy for estimating LMA from cuticle thickness (CT) in broad-leaved gymnosperms, and expand it across different foliage types and through the light gradient. This LMA-CT paleoproxy is a very attractive concept for assessing past ecosystem properties as cuticles are much more likely to be preserved in fossils than mesophyll. At the same time LMA is connected to many traits underlying the leaf economics spectrum as well as to some growth conditions like CO2 concentration and light availability. Paleoproxies are indeed a great tool to reconstruct the past environmental and ecological conditions for the plant, whose minute piece paleobotanists are studying millions of years later. However, as large generalizations are made based on tiny tiny preserved plant bits, we must make sure the correlations hold across many species and in different conditions. Thus, we tested the LMA-CT relationship on 86 gymnosperm species with broad leaves, needles and scales and used a sub-set to study the effect of growth light conditions on CT as its effect on LMA has been previously well established.

The relationship between LMA and CT in different leaf form types (graph from the paper)

Our results were promising! The proxy could be used for broad- and scale-leaved species, while the correlation does not hold for needles. Importantly, the reliability of the proxy increases for species at the lower end of the leaf economic spectrum (LES) – for species with tough robust leaves with high LMA – which is good considering that many of the so-called “living fossils” belong to that end of LES. However, we advise caution as taxonomy and light conditions affected the LMA-CT relationship, so just measuring CT from a diverse set of fossils may give you wrong results. Further tests distinguishing the morphotype of the fossilized leaf and the LMA-CT relationship in the nearest living relatives should be carried out. Nevertheless, CT on itself can give valuable information about the environmental conditions and stresses for the plant!

Full citation: Veromann-Jürgenson, L. L., Brodribb, T., Laanisto, L., Bruun-Lund, S., Niinemets, Ü., Nuño, S. L., Rinnan, R., Puglielli, G. & Tosens, T. (2019). Predictability of Leaf Morphological Traits for Paleoecological Reconstruction: The Case of Leaf Cuticle and Leaf Dry Mass per Area. International Journal of Plant Sciences, 181(1), https://doi.org/10.1086/706342 (link to full text)

 

A living fossil in its natural habitat in Australia (pic by Linda-Liisa)

 

Abstract:

Our power to predict the future relies on our knowledge of the past. Paleoproxies are a powerful tool for understanding environmental and ecological conditions, and changes across different time periods. However, constructing a functioning paleoproxy requires a well-constrained and robustly tested model. This is challenging, especially if ecological traits are involved. In the current study we constructed an extended dataset to test the reliability of the derivation of leaf dry mass per unit area (LMA) from the thickness of fossil gymnosperm cuticle. Specifically, we tested if different leaf types (broad leaves, needles, scales), intraspecific variability in cuticle thickness, and growing conditions affect the functioning of the proxy. Taxonomic groups were analyzed to uncover the possible taxonomic influence on LMA, cuticle thickness and the LMA-CT relationship. Our results indicate that the cuticle thickness versus LMA relationship depends on multiple factors that can have various and incongruous effects on this relationship, depending especially on leaf type and growing conditions. We conclude that cuticle thickness measured from gymnosperm fossils could be used as a proxy for LMA in past ecosystems for some broad- and scale-leaved, but not needle-leaved gymnosperms. However, caution must be taken when comparing species from different environments or growth conditions.

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