EcolChange seminar (25th November, Thursday): Enrico Tordoni about the threatened tetrapod diversity in the Anthropocene

Seminar of Department of Botany and Centre of Excellence EcolChange

Speaker: Dr. Enrico Tordoni (Department of Botany, University of Tartu)

Title of the talk: Tetrapod diversity in jeopardy in the Anthropocene

Time: Thursday, 25 November 2021 at 14.15

Place: Tartu, Lai 40-218 (mandatory for everyone to wear a mask), or virtual seminar in Zoom

Summary: Human activities have eroded biodiversity, yet the varying influence of past versus recent impacts across the distinct facets of biodiversity (taxonomic, phylogenetic and functional diversity) is still poorly understood. In this seminar, I will provide an overview on how the varying geography of the timing of agriculture expansion since the Neolithic affected the multifaceted diversity, which was synthesized across more than 17,000 tetrapod species using a new diversity index called mu-Diversity. The long-lasting effect of humans in biodiversity will only accelerate, with a 60% of regions hosting high mu-Diversity, mainly in tropical Africa and India, being disproportionally exposed to both future climate and land-use change.

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EcolChange seminar (11th November, Thursday): Ülo Mander and Jaan Pärn about greenhouse gas fluxes in wetland soils, tree stems and canopies

Seminar of Department of Botany and Centre of Excellence EcolChange

Speakers: Prof. Ülo Mander, PhD Jaan Pärn (Department of Geography, University of Tartu) 

Title of the talkGreenhouse gas fluxes in wetland soils, tree stems and canopies

Time: Thursday, 11 November 2021 at 14.15

Place: Tartu, Lai 40-218 (mandatory to present a covid certificate or to wear a mask), or virtual seminar in Zoom

Summary: Drained wetlands are significant sources of CO2 and N2O (commonly known as laughing gas) greenhouse gases (GHG) while natural wetlands emit methane. Little is known about the role of tree stems and canopies in transformation of the GHG fluxes. Here we present our research in global wetland soils, including a riparian deciduous forest in Estonia to a tropical palm swamp in the Peruvian Amazon.

 

photo from here
photo from here
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EcolChange seminar (4th November, Thursday): Anne Karhu about the new challenges for ecotoxicologists due to COVID-19 outbreak

Seminar of Department of Botany and Centre of Excellence EcolChange

Speaker: Prof. Anne Kahru (National Institute of Chemical Physics and Biophysics) 

Title of the talkNew challenges for ecotoxicologists due to COVID-19 outbreak: focus on metal-based antimicrobials and single-use plastic

Time: Thursday, 4 November 2021 at 14.15

Place: virtual seminar in Zoom

Summary: The Laboratory of Environmental Toxicology of National Institute of Chemical Physics and Biophysis (Tallinn, Estonia) has long-time experience in eco-safety evaluation of different types of nanomaterials (NMs) using a combined approach based on thorough physico-chemical characterization of NMs coupled to the bioassays with crustaceans, protozoa, algae, plants and microbes. The seminar will introduce COVID-19 outbreak-related challenges to ecotoxicologists. Firstly, the urgent need for novel antiviral materials has led to the rapidly increasing interest in use of e.g., copper and silver in different surface coatings, textiles and face masks etc. Indeed, silver, copper and zinc are efficient antimicrobials but have hazardous effects to aquatic species, especially to algae and crustaceans – important representatives of aquatic food chain. Secondly, the need for protection of humans against Coronavirus has led to warning increase of use of single-use plastics (masks, gowns, gloves) being contradictory to the pre-COVID strategy envisaging cutting down the single-use plastics. 

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EcolChange seminar (28th October, Thursday): Catrin Westphal about integrating biodiversity and ecosystem services into cropping systems and agricultural landscapes

Seminar of Department of Botany and Centre of Excellence EcolChange

Speaker: Prof. Catrin Westphal (Georg-August-Universität Göttingen)

Title of the talk: Integrating biodiversity and ecosystem services into cropping systems and agricultural landscapes

Time: Thursday, 28 October 2021 at 14.15

Place: virtual seminar in Zoom

Summary: Biodiversity within cropping systems is providing important ecosystem functions and services for agricultural production. To halt ongoing biodiversity declines due to agricultural intensification, measures are needed that aim at the diversification of cropping systems. This talk will focus on local and landscape scale measures that promote pollinators and crop pollination services. Moreover, changes in functional diversity of pollinator, bird and arthropod communities along gradients of local land use intensity and landscape heterogeneity will be explored.

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EcolChange seminar (21st October, Thursday): Kalle Olli about the alpha and beta diversity of phytoplankton communities in the Helsinki Archipelago

Seminar of Department of Botany and Centre of Excellence EcolChange

Speaker: Prof. Kalle Olli (Estonian University of Life Sciences/ University of Tartu)

Title of the talk: Trends in alpha and beta diversity of phytoplankton communities in the Helsinki Archipelago, the Baltic Sea

Time: Thursday, 21 October 2021 at 14.15

Place: Tartu, Lai 40-218 (mandatory to present a covid certificate or to wear a mask), or virtual seminar in Zoom

Summary: Helsinki City has possibly the best phytoplankton community time-series in the Baltic Sea.  We witness a conspicous temporal change in community composition and increas in species richness over half a century. Temporal beta trend reflects the notorious eutrophication history of the area, while spatial beta trends suggest progressing homogenisation in time.

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Excursion to EcolChange experimental sites

On 13th October, the EcolChange Coordinating Committee together with some colleagues gathered in Järvselja to visit three experimental sites.

photo by Tiia Kurvits

First stop was at the Agali experimental site run by the Ecotechnology and landscape biogeochemistry team (Prof. Ülo Mander, Assoc. Prof. Kaido Soosaar, Dr. Mikk Espenberg from the University of Tartu, Department of Geography). The experiment is used to study the emission and removal of greenhouse gases by forest ecosystem. The team measures gas exchange between atmosphere, soil, tree trunks and canopy to follow the movement of greenhouse gases and the sequestration of carbon.

Next site was SMEAR Estonia, which is used by the Plant ecophysiology and biosphere-atmosphere interactions team (Prof. Ülo Niinemets and Prof. Steffen M. Noe from the Estonian University of Life Sciences). The aim of the SMEAR (Station for Measuring Ecosystem-Atmosphere Relations) is to measure concentrations and fluxes of energy and matter in the atmosphere-biosphere system using a 130 m high measuring tower. In addition, soil and biomass measurements are taken on the ground level.

The third stop was at the FAHM (Free Air Humidity Manipulation) experiment site, which is run by the Ecophysiology workgroup (Assoc. Prof. Priit Kupper from the University of Tartu, Department of Botany), and where also several EcolChange members are collaborators. The experiment was created to investigate the impact of climate change (as elevated air humidity) on trees and forest ecosystem functioning.

photo by Tiia Kurvits
photo by Riin Tamme

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EcolChange seminar (14th October, Thursday): Stefano Mammola about the conservation of subterranean ecosystems

Seminar of Department of Botany and Centre of Excellence EcolChange

Speaker: Dr. Stefano Mammola (Research Fellow at CNR, IRSA: Water Research Institute, Verbania)

Title of the talk: Toward evidence-based conservation of subterranean ecosystems

Time: Thursday, 14 October 2021 at 14.15

Place: Tartu, Lai 40-218 (mandatory to present a covid certificate or to wear a mask), or virtual seminar in Zoom

Summary: Caves and other subterranean ecosystems are among the most widespread environments on Earth and contain a biota still poorly known. To raise awareness of subterranean ecosystems, the essential services they provide, and their unique conservation challenges, 2021 was designated the International Year of Cave and Karst. The time is ripe to provide a quantitative assessment of solution-based approaches to safeguard subterranean biota and associated habitats. During the seminar, I will present the result of an ongoing systematic review to quantify the available evidence for the effectiveness of conservation interventions in subterranean ecosystems. I will discuss the importance of making conservation efforts in subterranean systems more practical, cost-effective, and long-lasting.

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EcolChange seminar (12th October, Tuesday): James Bever about microbiome influence on plant communities

Seminar of Department of Botany and Centre of Excellence EcolChange

Speaker: Professor James Bever (University of Kansas)

Title of the talkDoes the microbiome drive plant community structure and function?

Time: Tuesday, 12 October 2021 at 15.15

Place: virtual seminar in Zoom

Summary: As we try to adapt to an increasingly dynamic climate in the Anthropocene, it is critical to correctly understand the drivers of diversity, composition and function in terrestrial ecosystems.  I will present evidence that the microbiome exerts strong influence on plant community diversity, composition and productivity.

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New publications about carbon in plant leaves

Originally posted in Ülo Niinemet’s Lab blog.

Text by Ülo Niinemets

Carbon, C, is the most frequent chemical element in plant leaves, but leaf carbon content is a surprisingly understudied plant trait. Modern elemental analyzers typically give estimates of nitrogen, N, and C contents, but often only N (that is present in proteins) is used and C is neglected. We have just shown that C in combination with Ca provides key insight into leaf structure and function both at local and global scales.

Looking back at this work, publication of these two papers was a saga. Lots of rejections, invitations to resubmit, revisions and rejections again. Many good comments, but also comments in a style “I just do not believe it”. This was the frustrating part of it. Perhaps it reflected the feeling in the research community that C and Ca are that common elements that there is nothing to find. Yet, people had not looked at these two key elements together. Taken alone, C and Ca are non-informative. Taken together, a marvelous set of patterns with major functional implications emerges.

figure from Xing et al. (2021, New Phytologist)

figure from Xing et al. (2021, New Phytologist)

The work builds upon an earlier study of Niinemets & Tamm (2005) that demonstrated a negative scaling between leaf structural carbon and leaf Ca content across woody species.

figure from Niinemets & Tamm (2005)

Citation: Xing, K., Zhao, M., Niinemets, Ü., Niu, S., Tian, J., Jiang, Y., Chen, H.Y.H., White, P.J., Guo, D. & Ma, Z. 2021. Relationships between leaf carbon and macronutrients across woody species and forest ecosystems highlight how carbon is allocated to leaf structural function. Frontiers in Plant Science 12: 674932 (link to paper).

Abstract: Stoichiometry of leaf macronutrients can provide insight into the tradeoffs between leaf structural and metabolic investments. Structural carbon (C) in cell walls is contained in lignin and polysaccharides (cellulose, hemicellulose, and pectins). Much of leaf calcium (Ca) and a fraction of magnesium (Mg) were further bounded with cell wall pectins. The macronutrients phosphorus (P), potassium (K), and nitrogen (N) are primarily involved in cell metabolic functions. There is limited information on the functional interrelations among leaf C and macronutrients, and the functional dimensions characterizing the leaf structural and metabolic tradeoffs are not widely appreciated. We investigated the relationships between leaf C and macronutrient (N, P, K, Ca, Mg) concentrations in two widespread broad-leaved deciduous woody species Quercus wutaishanica (90 individuals) and Betula platyphylla (47 individuals), and further tested the generality of the observed relationships in 222 woody eudicots from 15 forest ecosystems. In a subsample of 20 broad-leaved species, we also analyzed the relationships among C, Ca, lignin, and pectin concentrations in leaf cell walls. We found a significant leaf C–Ca tradeoff operating within and across species and across ecosystems. This basic relationship was explained by variations in the share of cell wall lignin and pectin investments at the cell scale. The C–Ca tradeoffs were mainly driven by soil pH and mean annual temperature and precipitation, suggesting that leaves were more economically built with less C and more Ca as soil pH increased and at lower temperature and lower precipitation. However, we did not detect consistent patterns among C–N, and C–Mg at different levels of biological organization, suggesting substantial plasticity in N and Mg distribution among cell organelles and cell protoplast and cell wall. We observed two major axes of macronutrient differentiation: the cell-wall structural axis consisting of protein-free C and Ca and the protoplasm metabolic axis consisting of P and K, underscoring the decoupling of structural and metabolic elements inherently linked with cell wall from protoplasm investment strategies. We conclude that the tradeoffs between leaf C and Ca highlight how carbon is allocated to leaf structural function and suggest that this might indicate biogeochemical niche differentiation of species.

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Citation: Xing, K., Niinemets, Ü., Rengel, Z., Onoda, Y., Xia, J., Chen, H.Y.H., Zhao, M., Han, W. & Li, H. 2021. Global patterns of leaf construction traits and their covariation along climate and soil environmental gradients. New Phytologist. (link to paper)

Abstract:

  • Leaf functional traits and their covariation underlie plant ecological adaptations along environmental gradients, but there is limited information on the global covariation patterns of key leaf construction traits.
  • To explore how leaf construction traits co-vary across diverse climate and soil environmental conditions, we compiled a global dataset including cell wall mass per unit leaf mass (CWmass), leaf carbon (C) and calcium (Ca) concentrations, and specific leaf area (SLA) for 2348 angiosperm species from 340 sites world-wide.
  • Our results demonstrated negative correlations between leaf C and Ca concentrations and between leaf C and SLA across diverse nongraminoid angiosperms. Leaf C concentration increased with increasing mean annual temperature (MAT) and mean annual precipitation (MAP) and with decreasing soil pH and calcium carbonate (CaCO3) concentration, whereas leaf Ca concentration and SLA exhibited the opposite responses to these environmental variables. The covariations of leaf Ca–C and of leaf SLA–C were stronger in habitats with lower MAT and MAP, and/or higher soil CaCO3 content.
  • This global-scale analysis demonstrates that the leaf C and Ca concentrations and SLA together govern the C and biomass investment strategies in leaves of nongraminoids. We conclude that environmental conditions strongly shape leaf construction traits and their covariation patterns.
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EcolChange seminar (7th October, Thursday): Sten Anslan about ecosystems in transition on the Third Pole

Seminar of Department of Botany and Centre of Excellence EcolChange

SpeakerSten Anslan is a Research Fellow at the University of Tartu.

Title of the talk: Ecosystems in transition on the Third Pole

Time: Thursday, 7 October 2021 at 14.15

Place: Tartu, Lai 40-218 (mandatory to present a covid certificate or to wear a mask), or virtual seminar in Zoom

Summary: The Tibetan Plateau (“The Third Pole”) is the highest and largest alpine plateau on Earth, where the effect of climate warming is expressed more strongly than the global average. In this seminar, I’ll present some of our recent research on tracking the environmental changes on the Tibetan Plateau triggered by the increasing anthropogenic pressure and climate warming. Additional information about the research in the Tibetian Plateae can be found here.

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