Lutz Eckstein, professor at Karlstad University, together with Yves Klinger, David Horlemann, Annette Otte and Kristin Ludewig recently published the paper Germination of the invasive legume Lupinus polyphyllus depends on cutting date and seed morphology in the journal NeoBiota. The paper is accessible open access on the journal website, or you can read a summary of the paper below:

In semi-natural grasslands, mowing leads to the dispersal of species that have viable seeds at the right time. For invasive plant species in grasslands, dispersal by mowing should be avoided, and information on the effect of cutting date on the germination of invasive species is needed. We investigated the germination of seeds of the invasive legume Lupinus polyphyllus Lindl. depending on the cutting date. We measured seed traits associated with successful germination that can be assessed by managers for an improved timing of control measures. Germination patterns were highly asynchronous and differed between seeds cut at different dates. Seeds cut early, being green and soft, tended to germinate in autumn. Seeds cut late, being dark and hard, were more prone to germinate the following spring, after winter stratification. This allows the species to utilize germination niches throughout the year, indicating a bet-hedging strategy.

Seed color and the percentage of hard seeds were good predictors of germination percentage. Managers should prevent the species from producing black and hard seeds, while cutting plants carrying green and soft seeds appears less problematic. Furthermore, germination patterns differed between experiments in climate chambers and in the common garden, mainly because germination of dormant seeds was lower in climate chambers. We propose that more germination experiments under ambient weather conditions should be done, as they can give valuable information on the germination dynamics of invasive species.

On Tuesday 14 January, Jacqueline Hoppenreijs, RivEM PhD-student, will give a seminar titled “Rooting for riparian vegetation”. Jacqueline will present her plans for her PhD project during the seminar, with emphasis on her fieldwork this summer.

The seminar starts at 13:15 in room 5F416 at Karlstad University. Everyone who wants to are welcome to attend the seminar.

 

 

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.).

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 (ф_ST = 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!

 

Two PhD positions (1: vegetation ecology, 2: ecosystem function/host-parasite interactions) are now open for applicants at Karlstad University. Both positions are full time for five years within the River Ecology and Management (NRRV) research group and include 80 % research and 20 % department duties (mainly teaching).

The applications for both positions close on 31 January 2019.

 

PhD position in vegetation ecology

The project will study which factors control diaspore dispersal and plant community composition along boreal streams, which in turn may have cascading effects on functional plant diversity and ecosystem functioning. The specific research questions to be addressed will be decided in consultation with the candidate. Areas of particular interest are (1) the effects of local and landscape-scale factors for plant species composition and diversity and cascading effects on ecosystem functioning and (2) studies of factors promoting or constraining plant dispersal along streams.

Read more and apply for the position here!

 

Ecosystem function/host-parasite interactions

The position will focus on either the role of mussels for ecosystem function or host-parasite interactions. Areas of interest are (1) the role of mussels for stream ecosystem function and (2) host-parasite interactions between mussels and their host fish. The specific research questions to be addressed will be decided in consultation with the candidate.

Read more and apply for the position here!