Lutz Eckstein is co-author of a paper presenting a workflow for iPhenology (Fig. 1), i.e., the use of publicly available photo observations to track phenological events at large scales. The paper, which has recently been published open access in the journal Methods in Ecology and Evolution (https://doi.org/10.1111/2041-210X.14114), is led by Yves Klinger (Justus-von-Liebig University Gießen, Germany), who will be visiting Biology at KaU in June 2023. Overall, publicly available citizen science photo observations are suitable to track key phenological events and can thus significantly advance the knowledge on the timing and drivers of plant phenology. In future, integrating the workflow with automated image processing and analysis may enable real-time tracking of plant phenology. To learn more about what sparked the idea for this paper and what may be advantages of working with citizen science photos, see the Methods in Ecology and Evolution blog (https://methodsblog.com/2023/05/22/using-citizen-science-photos-to-perform-phenological-studies/).
Lutz Eckstein is the lead author of a paper summarizing the current knowledge on the biology of the invasive legume Lupinus polyphyllus Lindley. The paper has recently been published in the journal Perspectives in Plant Ecology, Evolution and Systematics in the series “Biological Flora of Central Europe” (https://doi.org/10.1016/j.ppees.2022.125715). This work is a cooperation with Erik Welk (Martin-Luther-University Halle-Wittenberg and German Centre for Integrative Biodiversity Research (iDiv) Halle, Germany), Yves Klinger and Wiebke Hansen (both Justus Liebig University Giessen, Germany), Tommy Lennartsson and Jörgen Wissman (both Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden), Kristin Ludewig (University of Hamburg, Germany), and Satu Ramula (University of Turku, Finland).
The paper gives a thorough review of the species’ taxonomy, presents distribution maps for North America, Europa and the world (Fig. 1), illustrates the life cycle of L. polyphyllus, and it contains a comprehensive discussion of potential management options. During the research for this review, the authors encountered some doubtful information about L. polyphyllus that uncritically reiterates in several fact sheets, reports and webpages. One such erroneous piece of information refers to the apparently very high longevity of seeds, which was taken from a modelling study on seed longevity under optimal dry and cold storage conditions. Similarly, there is some uncertainty and large variation concerning the actual lifespan of the species. Another piece of doubtful information is the deep rooting depth of L. polyphyllus, which may rather characterize a maximum than a representative average value. Finally, the species is sometimes considered a “rhizomatous perennial” although it lacks true rhizomes. These points highlight some critical knowledge gaps, which partly relate to aspects of the species’ life cycle and morphology that may be either time-consuming or labor-intensive to study.
The authors conclude that there is currently no evidence-based strategy for a cost-efficient management of L. polyphyllus. The development of such control measures is necessary because L. polyphyllus is among the most problematic non-native plant species in Europe with respect to environmental and socio-economic impacts. The species has significant negative effects on community structure, composition, species richness and diversity, especially in nutrient-poor habitats such as alpic mountain hay meadows, alpic mat-grass swards but also nutrient-poor road verges or riparian terraces.
Lutz Eckstein is the senior author of a multi-author paper on the phenology and morphology of the invasive legume Lupinus polyphyllus along a latitudinal gradient in Europe. He has also been the project coordinator, while Kristin Ludewig (Hamburg University) has led the preparation of the paper, recently published in the journal NeoBiota (https://doi.org/10.3897/neobiota.78.89673). In total, 30 authors (researchers, students, consultants, conservation agency employees) have been involved in this project and the publication. Each co-author contributed data of a lupine population and the whole project covered a >2000 km long latitudinal gradient including the countries Luxembourg, Germany, Poland, Denmark, Sweden and Norway (Fig. 1).
Plant phenology is the timing of seasonal events, such as budburst, greening, flowering, and fruit ripening. Phenology influences the fitness of individual plants, controls species distribution ranges, and may have cascading effects on communities and ecosystems. Temperature is one of the most important drivers of plant phenology together with day length. However, the potential for adaptation of phenology may also be key to understanding the success of invasive plant species, which will benefit from ongoing global change. Lupinus polyphyllus Lindl. (Fabaceae) is a perennial herbaceous hemicryptophyte originating from western North America that was introduced in Central Europe as an ornamental plant in the 19th century. From Central Europe and Scandinavia, the species spread very successfully to almost all parts of Europe, now ranging from the Pyrenees in the West to the Ural (and beyond) in the East (Eckstein et al., unpublished data). From North to South, L. polyphyllus is currently covering the full range of Europe, except for Mediterranean zones such as the Iberian Peninsula and Italy.
The overall aim of the paper was to understand how the timing, temperature dependence of flowering and fruiting, and performance (canopy height, potential seed production and seed release height) of L. polyphyllus change along the latitudinal gradient from Central to Northern Europe. The authors tested differences between populations from different climatic zones and quantified variation in phenology in relation to latitude. The present study is probably the first attempt to quantify variation in phenology of an invasive plant across a large latitudinal gradient in the field.
The paper studied variation in growth and phenology of flowering and fruiting of L. polyphyllus using measurements and >1600 digital photos of inflorescences from 220 individual plants observed weekly at 22 sites. While canopy height of plants did not vary significantly along the latitudinal gradient, the day of the year (doy) at which different phenological phases were reached, increased 1.3–1.8 days per degree latitude (Fig. 2), whereas the growing degree days (gdd) required for these phenological phases decreased 5–16 gdd per degree latitude. However, this difference disappeared, when the day length of each day included in the calculation of gdd was accounted for (Fig. 2). The day of the year of the earliest and the latest climatic zone to reach any of the four studied phenological phases differed by 23–30 days and temperature requirements to reach these stages differed between 62 and 236 gdd. Probably, the invasion of this species will further increase in the northern part of Europe over the next decades due to climate warming. For invasive species control, the results suggest that in countries with a large latitudinal extent, the mowing date should shift by ca. one week per 500 km at sites with similar elevations to target the species in the same phenological phase.
Louis Addo (Doctoral Student), Mahboobeh Hajiesmaeli (Post-doctoral Researcher), John Piccolo (Professor) and John Watz (Associate Professor in Biology) all from the River Ecology and Management Research Group RivEM, Department of Environmental and Life Sciences at Karlstad University have recently published a paper entitled “Growth and mortality of sympatric Atlantic salmon and brown trout fry in fluctuating and stable flows” with the journal Ecology of Freshwater Fish.
In their paper, they explore the potential effects of hydropeaking or short-term regulated rivers on the growth and mortality of sympatric Atlantic salmon (Salmo salar) and brown trout (Salmo trutta) at the fry life stage.
Professor John Piccolo was involved in two recently published articles and a podcast about ecological sustainability. The two articles and the podcast are part of a larger project on ecological sustainability that John is part of, with researchers from around the globe.
Mattias Hansson, Lovisa Lind, Andreas Vernby, Larry Greenberg and Johan Watz from Karlstad University have a new paper out! It describes how Hester-Dendy samplers perform under different flow regimes. This was tested in a laboratory experiment by studying the colonization of the Hester-Dendy samplers in relation to a predetermined benthic macroinvertebrate composition in a fluctuating (and increasing) flow regime and in a constant flow regime.
The results showed that flow conditions didn’t affect the number of colonizing individuals, but the sampled species diversity was negatively affected by the fluctuating flow regime. This indicates that sampling benthic macroinvertebrates from rivers and streams with sub-daily flow changes, for example downstream of hydropeaking power plants, may be subject to a negative sampling bias.
Professor Lutz Eckstein is co-author in a new paper in the journal Applied Vegetation Science led by Yves Klinger (Justus-Liebig-University Giessen, Germany). The authors assessed the role of mowing machinery and endozoochory by migratory sheep as dispersal vectors in semi-natural grasslands by comparing the species compositions and traits of species found in the vectors to the regional above-ground vegetation and soil seed bank. Plant material from mowers (n = 12 from one date) and dung samples from migratory sheep (n = 39 from 13 dates) were collected and the dispersed plant species were determined using the emergence method. We compared the species compositions to the regional above-ground vegetation and seed bank using non-metric multidimensional scaling (NMDS) and indicator species analysis. Furthermore, we compared functional traits of the dispersed species to traits of non-dispersed species of the regional species pools by calculating log-response ratios and performing metaregressions.
We found that mower samples were more similar to the above-ground vegetation whereas dung samples were more similar to the seed bank. Mowers and sheep endozoochory favored the dispersal of species with different traits and phenologies. Species with small seed sizes were prevalent in both vectors. Mowers were less selective concerning most traits, but favored high-growing grasses such as Alopecurus pratensis and Trisetum flavescens. Sheep dung samples contained less grasses and more palatable species, such as Urtica dioica.
Sheep endozoochory and mowing machinery are complementary dispersal vectors favoring species with differing functional traits. Sheep endozoochory enables dispersal of species that have unfavorable traits (e.g. low releasing heights) or phenologies for dispersal by mowing machinery. To ensure the dispersal of a high number of plant species in semi-natural grasslands, the interplay of different vectors should be considered.
Professor Lutz Eckstein is involved in a new article led by Eva Svensson (Dept. of Political, Historical, Religious and Cultural Studies, KaU) and co-authored by Jan Haas (Geomatics, KaU) in the journal Landscapes (Taylor & Francis). They tested the potential of a low-budget method for integrating information on human impact and natural responses in the vegetation of boreal forested Scandinavia. The information from two national databases in Sweden – the National Inventory of Landscapes in Sweden (NILS) covering surveyed vegetation, and the Register of Ancient Monuments (Fornsök) – were combined and visualized using Geographical Information Systems (see Figure).
No relationships between human impact and vegetation were found at any of the five investigated sites. The authors discuss potential reasons for this, among others mismatches in time and scale between databases but also sectorized survey methods not paying attention to biocultural heritage, landscape perspectives or long-term processes. The paper concludes that further development of survey methods and registers targeting contexts and processes are called for. “This is a good example of `negative´ results, i.e. a study that does not demonstrate any significant patterns being published in an international scientific journal”, says Lutz Eckstein. Read more about the paper here: https://doi.org/10.1080/14662035.2020.1905202.
A group of international researchers, among which Martin Österling, have a new paper out! The authors, led by Ronaldo Sousa from the University of Minho in Portugal, investigated the role of anthropogenic habitats as refuges for freshwater mussels. The dataset of 709 sites comprised 228 mussel species, of which 34 are threatened, in a broad variety of anthropogenic habitat types. The authors assessed the conservation importance of these anthropogenic habitats, which included both refuges and ecological traps, and provide guidance for the conservation of freshwater mussels. Read the full paper here: https://onlinelibrary.wiley.com/doi/10.1111/gcb.15549
Andrew Harbicht, Martin Österling, and Olle Calles from Karlstad University and Anders Nilsson of Lund University have a new paper out. By radio tagging Atlantic salmon smolt and following them along their downstream migration to the Baltic, they quantified the effect of both a dam and a reservoir on migratory rates while accounting for environmental covariates. The good news for salmon, if reservoirs are kept thin (river-like), and mitigative measures are taken at a dam (i.e., spilling water during the smolt migration), the effects of anthropogenic barriers can be dramatically reduced. Read more about the paper here: https://doi.org/10.1002/rra.3760