New publication – Global database of plants with root‐symbiotic nitrogen fixation: Nod DB

Text by Lauri Laanisto

It´s really a very simple paper! A (relatively little) database containing information about all the plants (on genus level) that fix nitrogen from the soil. Somehow this information has not been available so far in a comparable and trustworthy way. Plus, it´s readily accessible – in a form or Excel table. Together with some additional taxonomic information for both plant and bacterial taxa, estimation of consensus, comparison with other sources that have tackled the same topic. To an ecologist, especially macroecologist, this dataset is a great source for easily getting potentially crucial trait added to your dataset. Because, as you can see from the GBIF-data based analysis (see the graph below), the proportion of N-fixing plants can differ quite a lot on global scale.

Citation: Tedersoo, L., Laanisto, L., Rahimlou, S., Toussaint, A., Hallikma, T., & Pärtel, M. (2018). Global database of plants with root‐symbiotic nitrogen fixation: Nod DB. Journal of Vegetation Science, doi.org/10.1111/jvs.12627 (link to full text)

nod db

Figure 2 from the paper: Species richness of N-fixing vascular plants relative to total species richness as based on all GBIF vascular plant records with coordinates. Relative richness is calculated per equal area polygons (ISEA3H) with size ca 7,000 km2. Colours show quantiles. Only terrestrial polygons hosting more than 50 records are shown.

Abstract:

Plants associated with symbiotic N‐fixing bacteria play important roles in early successional, riparian and semi‐dry ecosystems. These so‐called N‐fixing plants are widely used for reclamation of disturbed vegetation and improvement of soil fertility in agroforestry. Yet, available information about plants that are capable of establishing nodulation is fragmented and somewhat outdated. This article introduces the NodDB database of N‐fixing plants based on morphological and phylogenetic evidence (available at https://doi.org/10.15156/bio/587469) and discusses plant groups with conflicting reports and interpretation, such as certain legume clades and the Zygophyllaceae family. During angiosperm evolution, N‐fixing plants became common in the fabid rather than in the ‘nitrogen‐fixing’ clade. The global GBIF plant species distribution data indicated that N‐fixing plants tend to be relatively more diverse in savanna and semi‐desert biomes. The compiled and re‐interpreted information about N‐fixing plants enables accurate analyses of biogeography and community ecology of biological N fixation.

Advertisements
Posted in New paper published | Tagged , , , , , , , | Leave a comment

Workgroup and EcolChange seminar – Kaia Kask about why Australia matters

Seminar of Chair of Crop Science and Plant Biology and Centre of Excellence EcolChange, Estonian Univ of Life Sciences .

Kaia Kask is a junior researcher and PhD-student in the Estonian University of Life Sciences.

Title of the talk: Measurements in Australia: what and why?

Time: Monday, 21. May 2018 at 10.15

Place: Tartu, Kreutzwaldi 5 – D-143 (Metsamaja, Aquarium-room)

Posted in Seminar/Lecture | Tagged , , , | Leave a comment

New publication – Structural controls on photosynthetic capacity through juvenile‐to‐adult transition and needle aging in Mediterranean pines

Text by Vivian Kuusk

Mediterranean pines are known for stress tolerance as they live in harsh environment where shortage of water is very common. All pines, but especially Mediterranean ones grow and keep different looking needles while they are young or adult. Young needles are quite soft and contain mainly photosynthetic tissue and have much less supportive tissue than adult needles. The study is about finding out the advantage of juvenile needles for the tree.

We concluded that due to different needle structure there are age-dependent differences in needle photosynthetic potentials, nitrogen use efficiency and mesophyll conductance that contribute to juvenile plants early growth and establishment. The experiment clarified more deeply our understanding of structural limitations to photosynthesis. Young seedlings need favorable conditions to survive, but when the chance is present, they grow needles that are as low cost and as efficient in photosynthesis as possible. Only after proper establishment of root system and couple of shoots, more durable needles are grown.

Citation: Kuusk, V., Niinemets, Ü., & Valladares, F. (2018). Structural controls on photosynthetic capacity through juvenile‐to‐adult transition and needle aging in Mediterranean pines. Functional Ecology, DOI: 10.1111/1365-2435.13087 (link to full text)

old-father-christmas-made-with-pine-cones-vintage-crafts-and-more

Old pine-man (pic from here)

Abstract

  1. Needle photosynthetic potentials strongly vary among primary (juvenile) and secondary (adult) needles (heteroblasty) in Pinus species, but there is limited understanding of the underlying structural, diffusional and chemical controls.
  2. We studied differences in needle photosynthetic characteristics among current‐year juvenile and adult needles and among different‐aged adult needles in Mediterranean pines Pinus halepensis Mill., P. pinea L. and P. nigra J. F. Arnold subsp. salzmannii (Dunal) Franco, hypothesizing that needle anatomical modifications upon juvenile‐to‐adult transition lead to reduced photosynthetic capacity due to greater limitation of photosynthesis by mesophyll conductance and due to an increase in the share of support tissues at the expense of photosynthetic tissues. We also hypothesized that such alterations occur with needle ageing, but to a lower degree.
  3. Photosynthetic capacity per dry mass was 2.4‐ to 2.7‐fold higher in juvenile needles, and this was associated with 3.4‐ to 3.7‐fold greater mesophyll diffusion conductance, 2‐ to 2.5‐fold greater maximum carboxylase activity of Rubisco (Vcmax) and 2.2‐ to 3‐fold greater capacity for photosynthetic electron transport (Jmax). The latter differences were driven by modifications in mesophyll volume fraction and changes in the share of nitrogen between structural and photosynthetic functions. Analogous changes in photosynthetic characteristics occurred with needle ageing, but their extent was less.
  4. These results indicate that conifer foliage photosynthetic machinery undergoes a profound change from a fast return strategy in juveniles to slow return stress‐resistant strategy in adults and that this strategy shift is driven by modifications in foliage biomass investments in support and photosynthetic functions as well as by varying mesophyll diffusional controls on photosynthesis. Changes in needle morphophysiotype during tree and needle ageing need consideration in predicting changes in tree photosynthetic potentials through tree ontogeny and during and among growing seasons.

 

Posted in New paper published | Tagged , , , , , , , , , , | Leave a comment

Workgroup and EcolChange seminar – Ivo Voor about fertilising peas

Seminar of Chair of Crop Science and Plant Biology and Centre of Excellence EcolChange, Estonian Univ of Life Sciences .

Ivo Voor is a PhD-student in the Estonian University of Life Sciences.

Title of the talk: The field pea yield and nitrogen balance depending different fertilizer rates

Time: Monday, 7. May 2018 at 10.15

Place: Tartu, Kreutzwaldi 5 – D-143 (Metsamaja, Aquarium-room)

Posted in Uncategorized | Tagged , , , , , | Leave a comment

New publication – Fertilising semi‐natural grasslands may cause long‐term negative effects on both biodiversity and ecosystem stability

Text by Lauri Laanisto

Community ecology was once famously described as ‘collecting stamps’ by John Lawton, as every community is so different and unique in so many ways. Therefore, instead of making generalisations, one can only study unique communities the way a collector studies their unique collection – a very post-truth-style statement from 20 years ago! However, Lawton was merely being provocative, and he actually suggests that there are indeed general laws in ecology – widespread, repeatable patterns, although not universally true in all cases.

Through the enormous bulk of ecological literature, it is very difficult to pinpoint these laws. Most of us, when publishing new results, tend to focus on the validity of the results and formulate found patterns as more or less general rules that might indeed hold unless specifically tested in other scales and places. As a result, there are a number of contradictory ideas and concepts floating around in ecological literature. Everything seems contingent.

So, sometimes little bubbles form in science, where some fundamentals have gone missing, or are discarded for some reason. The impulse to discard fundamentals might come, not from the theoretical thinking itself, but from something outside of it. For example, waste from agriculture and biotechnology, which needs to be offloaded somewhere and preferably cheaply. Combine it with the ‘balance of nature’ concept that is known not to work in ecological systems, and it might as well culminate in ‘let’s give back to nature’ type-thinking, which can result in spreading slurry in grasslands, or at its worst, a cynical approach to waste management

Our Commentary addresses several studies that have sought ways to get rid of waste by giving it back to where it originally came from – grasslands. Specifically, recent publications have recommended fertilising semi-natural temperate grasslands with nutrient residues like digestate and slurry. These studies claim that fertilising grasslands increases productivity but has no negative effect on species richness. We highlight three aspects that should be considered before fertilising diverse grassland communities, which are based on fundamental ecological knowledge and long-term experiments.

Everything is not necessarily contingent after all …

/This blog post was originally written and publised in JAPPL blog/ (link)

Citation: Melts, I., Lanno, K., Sammul, M., Uchida, K., Heinsoo, K., Kull, T., & Laanisto, L. (2018). Fertilising semi‐natural grasslands may cause long‐term negative effects on both biodiversity and ecosystem stability. Journal of Applied Ecology, DOI 10.1111/1365-2664.13129: (link to full text)

800px-laelatu_puisniit

Laelatu wooded meadow in Western Estonia: one of the most diverse semi-natural grasslands in the world [Image by Margus6 va Wikimedia Commons]

Abstract:

  1. Some short‐term experiments in applied ecology and agricultural research have demonstrated that nutrient applications in semi‐natural grasslands can maintain productivity and will not result in the decrease of plant species richness. Such findings may have an impact on management choices and quality of valuable plant communities, and therefore, further discussion of this topic is necessary.
  2. We highlight three aspects regarding the management suggestions in grassland communities with high biodiversity: (1) short‐term study results may not reflect potential long‐term changes; (2) broad range of grasslands may respond to disturbance in site specific ways; and (3) practical advices should contain careful consideration of existing ecological literature regarding grassland management and sustainable biodiversity.
  3. Synthesis and applications. Considering effects of fertilisation on biodiversity, we argue against nutrient application to semi‐natural grasslands. Biodiversity supports the resilience of grassland ecosystems and maintains a stable biomass yield. Current short‐term experiments are good indicators about the need for a long‐term experiments and meta‐analysis for detailed understanding of ecosystem functions in different types and areas during global change.
Posted in New paper published | Tagged , , , , , , , , | Leave a comment

Workgroup and EcolChange seminar – Ragnar Viikoja about wheat stress

Seminar of Chair of Crop Science and Plant Biology and Centre of Excellence EcolChange, Estonian Univ of Life Sciences .

Ragnar Viikoja is a PhD-student in the Estonian University of Life Sciences.

Title of the talk: The impact of stress on the yield of wheat in different farming systems

Time: Monday, 23. April 2018 at 10.15

Place: Tartu, Kreutzwaldi 5 – D-143 (Metsamaja, Aquarium-room)

ukr-jitnitsa

Highly stressful (just a single plant species has survived!) wheat landscape in Ukraine (pic from here)

 

Posted in Seminar/Lecture | Tagged , , , , | Leave a comment

Workgroup and EcolChange seminar – Dimitrii Krasnov about forest soil heterogeneity

Seminar of Chair of Crop Science and Plant Biology and Centre of Excellence EcolChange, Estonian Univ of Life Sciences .

Dimitrii Krasnov is a junior researcher and a PhD-student in the Estonian University of Life Sciences.

Title of the talk: Spatial heterogeneity of the soil in mixed forest

Time: Monday, 9. April 2018 at 10.15

Place: Tartu, Kreutzwaldi 5 – D-143 (Metsamaja, Aquarium-room)

dmitrii

Nightside steampunk soil profiling (photo from Dmitrii´s facebook page)

Posted in Seminar/Lecture | Tagged , , , , , | Leave a comment