The paper led by scientists of the Department of Engineering and Chemical Sciences, Karlstad University, was co-authored by Lutz Eckstein, professor of biology at the Department of Environmental and Life Sciences.


He writes about their work:

“Sweden has about 28 million hectares of forests, and pine trees constitute 40% of the total standing volume. Since the country is the world’s second largest exporter of pulp, paper and wood products, a total of 400 million containerized tree seedlings are produced by Swedish forest nurseries to restock forests each year. However, intensive annual forest harvests remove essential soil nutrients, which may cause problems for forest productivity.

In Sweden, container-grown seedlings are dominantly produced in peat and peat-based growth media. Peat-based substrates have many advantages such as long-term drainage ability, good aeration for tree seedling roots, good fertilizer absorbance and release capability. However, peat-based media are considered non-sustainable as their extraction have adverse environmental impacts. Therefore, sustainable approaches towards forest production and plantation management are urgently needed.

Therefore, the aim of this paper was to study the effects of hydrochar, derived from paper mill biosludge, on growth, quality, mycorrhizal associations and nutrient/heavy metal uptake of pine tree seedlings. We analyzed whether effects varied significantly between hydrochar forms (powder or pellets) or hydrochar proportions mixed with peat (10% or 20% hydrochar v/v). The effects of hydrochar addition on pine tree seedling was evaluated under three fertilization regimes (no fertilizer, 50% fertilizer and 100% fertilizer). We hypothesized that the growth, quality and mycorrhizal colonization of pine tree seedlings grown in substrate mixed with hydrochar would improve. We also expected pine tree seedlings grown with hydrochar to require less fertilizer to achieve similar or higher growth, mycorrhizal colonization and associated nutrient uptake relative to seedlings grown without hydrochar but with optimum rates of fertilizer (100% fertilizer). To our knowledge, this current study is the first paper to explore the potentials of hydrochar powder and pellets for being used as a growing media component in production of containerized pine tree seedlings.

Application of hydrochar had positive or neutral effects on shoot biomass and stem diameter compared with control seedlings (without hydrochar) under tested fertilizer levels. Analysis of the natural logarithmic response ratios (LnRR) of quality index and nutrient and heavy metal uptake revealed that application of 20% (v/v) hydrochar powder or pellet with 50% fertilizer resulted in same quality pine seedlings with similar heavy metal (Cu, Ni, Pb, Zn and Cr) and nutrient (P, K, Ca and Mg) contents as untreated seedlings supplied with 100% fertilizer. Colonization percentage by ectomycorrhizae significantly increased when either forms of hydrochar were applied at a rate of 20% under unfertilized condition. The results of this study implied that application of proper rates of hydrochar from biosludge with adjusted levels of liquid fertilizer may reduce fertilizer requirements in pine nurseries.”

Read the paper for free here! 

Yves P. Klinger, Sarah Harvolk-Schöning, Lutz Eckstein, Wiebke Hansen, Annette Otte and Kristin Ludewig recently published the paper ”Applying landscape structure analysis to assess the spatio-temporal distribution of an invasive legume in the Rhön UNESCO Biosphere Reserve” in the journal Biological Invasions.

Lutz Eckstein, Professor in Biology at Karlstad University, writes about their work:

The legume Lupinus polyphyllus. Photo by Lutz Eckstein

“We applied a combination of aerial mapping and GIS-based landscape analysis to study the invasion of the legume, Lupinus polyphyllus, in the Rhön UNESCO Biosphere Region as a case. We assessed the changes in lupine distribution between 1998 and 2016 in a strictly protected part of the Biosphere Region by means of landscape structure analysis. The area invaded by L. polyphyllus doubled from 1998 to 2016. The number of lupine stands decreased by 25%, but average stand size increased by 300%. In 2016, large and well-connected mesic grasslands that were situated close to roads were more heavily invaded than small and remote wet grasslands. Our results show that landscape composition plays an important role for the spread of invasive plants. Specifically, invasive stand characteristics, such as stand size, form, and connectivity, are crucial for driving the invasion process. Therefore, in addition to landscape composition, invasive stand characteristics should be included in the planning of conservation measures. Overall, aerial mapping combined with landscape analysis provides a cost-effective and practical tool for landscape managers to prioritize invasive control measures.”

Access the paper here, or contact any of the authors.

För ungefär en månad sedan uppmärksammade vi en forskningsartikel som handlade om hur grågåsen genom sin spillning är viktig för växters spridning på skärgårdsöar i Östersjön (läs inlägget här). Lutz Eckstein, Professor i NRRV, är medförfattare på artikeln.

Nu har forskningen fått stort mediegenomslag, och uppmärksammats av bland annat Sveriges Radio (lyssna på ett inslag där Lutz berättar om studien), Aftonbladet, Svenska Dagbladet, Ny Teknik samt en mängd lokaltidningar (Smålandsposten, Kristianstadsbladet, Bohuslänningen, Enköpingsposten, Borås tidning, Uppsala nya tidning, Katrineholms-Kuriren m.fl.).

Dirk Hattermann, Markus Bernhardt-Römermann, Annette Otte  and Lutz Eckstein recently published the paper “Geese are overlooked dispersal vectors for vascular plants in archipelago environments” in Journal of Vegetation Science.

 

In the abstract, the authors write:

 

“Question

We addressed the importance of gut‐mediated dispersal by Greylag Goose for vascular plants in archipelago environments and asked:

(i) What proportion of the local species pool is dispersed by geese?.

(ii) Which plant traits characterize species dispersed by geese?.

(iii) Which plant communities are likely to benefit from endozoochory by geese?.

 

Location

Three Swedish Baltic archipelagos.

 

Methods

Goose droppings were collected on 45 islands. Plants germinating from the droppings represent the endozoochorous species pool (ESP). On 108 islands, the presence of vascular plants was recorded in each habitat. These species represent the island species pool (ISP). Differences in functional traits between ESP and ISP were expressed as effect sizes and tested using meta‐regressions. Using indicator species analyses and indicator species for managed semi‐natural grasslands, we identified the primary habitats of the ESP.

 

Results

Geese dispersed viable diaspores of 97 plant species, which represents 22% of the ISP. Most ESP species were typical for small islands. Geese dispersed a higher proportion of graminoids and less woody plants, higher proportions of chamaephytes and therophytes and less phanerophytes; annuals and bi‐annuals were significantly overrepresented. One average, seed volume of the ESP was 95 % smaller than that of the ISP. About 51% of all ESP species were dispersed in at least two archipelagos. Geese showed a bias towards species of rocky shore habitats.

 

Conclusion

Geese potentially disperse large amounts of diaspores of many terrestrial island plant species. Through their feeding behaviour, geese select species with certain suites of traits from the regional species pool. Plant dispersal by geese may benefit plants species of rocky shores, but species of formerly managed semi‐natural grasslands may also find refuge sites on epilittoral shores after goose‐mediated dispersal. The relative importance of geese as dispersal vectors may increase under ongoing land‐use changes and cessation of grazing networks.”

 

Access the paper here, or contact any of the authors.

Viola elatior and the two habitats used in the study: early successional floodplain meadows and late successional alluvian woodlands. Photos: Benjamin Schulz.

Benjamin Schulz, Walter Durka, Jiří Danihelka and Lutz Eckstein recently published the research paper “Differential role of a persistent seed bank for genetic variation in early vs. late successional stages” in the scientific journal PLOS ONE. In the abstract, the authors write:

“Persistent seed banks are predicted to have an important impact on population genetic processes by increasing effective population size and storing past genetic diversity. Accordingly, persistent seed banks may buffer genetic effects of disturbance, fragmentation and/or selection. However, empirical studies surveying the relationship between aboveground and seed bank genetics under changing environments are scarce. Here, we compared genetic variation of aboveground and seed bank cohorts in 15 populations of the partially cleistogamous Viola elatior in two contrasting early and late successional habitats characterized by strong differences in light-availability and declining population size. Using AFLP markers, we found significantly higher aboveground than seed bank genetic diversity in early successional meadow but not in late successional woodland habitats. Moreover, individually, three of eight woodland populations even showed higher seed bank than aboveground diversity. Genetic differentiation among populations was very strong (фST = 0.8), but overall no significant differentiation could be detected between above ground and seed bank cohorts. Small scale spatial genetic structure was generally pronounced but was much stronger in meadow (Sp-statistic: aboveground: 0.60, seed bank: 0.32) than in woodland habitats (aboveground: 0.11; seed bank: 0.03). Our findings indicate that relative seed bank diversity (i.e. compared to aboveground diversity) increases with ongoing succession and despite decreasing population size. As corroborated by markedly lower small-scale genetic structure in late successional habitats, we suggest that the observed changes in relative seed bank diversity are driven by an increase of outcrossing rates. Persistent seed banks in Viola elatior hence will counteract effects of drift and selection, and assure a higher chance for the species’ long term persistence, particularly maintaining genetic variation in declining populations of late successional habitats and thus enhancing success rates of population recovery after disturbance events.”

Read the paper here!

 

Dirk Hattermann (Justus Liebig University Giessen), Markus Bernhardt-Römermann (Friedrich Schiller University Jena), Annette Otte (Justus Liebig University Giessen) and Lutz Eckstein (Karlstad University) recently published the paper “New insights into island vegetation composition and species diversity – Consistent and conditional responses across contrasting insular habitats at the plot-scale” in the scientific journal PLOS ONE.

In the abstract the authors write:

“Most island-ecology studies focus on the properties of entire island communities, thus neglecting species-environment relationships operating at the habitat-level. Habitat-specific variation in the strength and sign of these relationships will conceal patterns observed on the island scale and may preclude a mechanistic interpretation of patterns and processes. Habitat-specific species-environment relationships may also depend on the descriptor of ecological communities. This paper presents a comprehensive plot-based analysis of local vegetation composition and species diversity (species richness and species evenness) of (i) rocky shore, (ii) semi-natural grassland and (iii) coniferous forest habitats in three Baltic archipelagos in Sweden. To identify differences and consistencies between habitats and descriptors, we assessed the relative contributions of the variable-sets “region”, “topography”, “soil morphology”, “soil fertility”, “soil water”, “light availability”, “distance” and “island configuration” on local vegetation composition, species richness and species evenness. We quantified the impact of “management history” on the descriptors of local grassland communities by a newly introduced grazing history index (GHI). Unlike species diversity, changes in vegetation composition were related to most of the variable-sets. The relative contributions of the variable-sets were mostly habitat-specific and strongly contingent on the descriptor involved. Within each habitat, richness and evenness were only partly affected by the same variable-sets, and if so, their relative contribution varied between diversity proxies. Across all habitats, soil variable-sets showed highly consistent effects on vegetation composition and species diversity and contributed most to the variance explained. GHI was a powerful predictor, explaining high proportions of variation in all three descriptors of grassland species communities. The proportion of unexplained variance was habitat-specific, possibly reflecting a community maturity gradient. Our results reveal that species richness alone is an incomplete representation of local species diversity. Finally, we stress the need of including habitat-based approaches when analyzing complex species-environment relationships on islands.”

You can access the paper here.

NRRV i media

Posted by Daniel Nyqvist | Nyheter

Under sommarmånaderna har NRRV-forskares arbete eller expertis uppmärksammats i olika media. Hallandsposten skrev om passagestudier med ålyngelstudier i Laholm och intervjuade Jonas Elghagen, Lutz Eckstein intervjuades angående den invasiva lupinen i Värmlands Folkblad,och en av Anders Nilssons senaste artiklar – om hur mört-braxen-hybrider är känsligare för predation än braxen och mört –  uppmärksammades av The Economist.

meadow

A floodplain meadow.

The scientific article “Flooding tolerance of four floodplain meadow species depends on age” by Gattringer, Donath, Eckstein, Ludewig, Otte and Harvolk-Schöning was recently published in the journal PLoS-One. Lutz Eckstein, one of the coauthors, is a professor within the River Ecology and Management research group at Karlstad University, whereas the other authors represent Justus-Liebig-University Giessen and Kiel University.

In then the abstract the authors write: “Numerous restoration campaigns focused on re-establishing species-rich floodplain meadows of Central Europe, whose species composition is essentially controlled by regular flooding. Climate change predictions expect strong alterations on the discharge regime of Europe’s large rivers with little-known consequences on floodplain meadow plants.

In this study, we aim to determine the effects of flooding on seedlings of different ages of four typical flood meadow species. To this end, we flooded seedlings of two familial pairs of flood meadow species of wetter and dryer microhabitats for 2 weeks each, starting 2, 4, 6, and 8 weeks after seedling germination, respectively.

We show that a 2-week-flooding treatment had a negative effect on performance of seedlings younger than 6 weeks. Summer floods with high floodwater temperatures may have especially detrimental effects on seedlings, which is corroborated by previous findings. As expected, the plants from wet floodplain meadow microhabitats coped better with the flooding treatment than those from dryer microhabitats.

In conclusion, our results suggest that restoration measures may perform more successfully if seedlings of restored species are older than the critical age of about 6 weeks before a spring flooding begins. Seasonal flow patterns may influence vegetation dynamics of floodplain meadows and should, therefore, be taken into account when timing future restoration campaigns.”

Access the paper online here: Flooding tolerance of four floodplain meadow species depends on age.

Forskare inom NRRV vid Karlstads Universitet ska under de kommande tre åren undersöka ekologiska effekter av utrivningen av en kraftverksdamm, samt hur fisk påverkas av så kallade “fiskvänliga” turbiner. Forskningen kommer att ske i Mörrumsån (dammutrivning) och i Emån (fiskvänlig turbin). De involverade forskarna är (än så länge) Lutz Eckstein, Anders Nilsson, Olle Calles och Martin Österling och gruppen förväntas undesöka allt från växtsamhällen till fiskars beteende. Projektet finansieras av KK-stiftelsen och är ett samarbete mellan Karlstads Universitet, Uniper, Sveaskog och Power house. Läs mer om projektet på fiskejournalen.se eller på kau.se.

Är du en disputerad biolog som tycker att det här låter intressant? Projektet har utlyst en postdoc tjänst. Läs mer här.