Mean ecological indicator values: which system and which weighting approach to use

Post provided by Grzegorz OstrowskiSeverin AicherAgnieszka Mankiewicz & Jürgen Dengler, originally posted to vegsciblog.org.

Mean ecological indicator values (EIVs) are widely used by vegetation ecologists throughout Europe. They allow for an efficient assessment of site conditions (bioindication) of vegetation plots when measurements of the physical, chemical or land use conditions would be too costly or time-consuming or not possible at all, for example, for the millions of legacy data.

The principle of EIVs was independently invented by Heinz Ellenberg in Germany and L.G. Ramensky in Russia. Due to their high utility, to date, more than 30 EIV systems have been published in Europe, largely varying in indicators, definitions, scaling and plant nomenclature, thus impeding pan-European studies. To overcome these impediments, in early 2023, within a few days, two EIV systems were published for Europe: the Ellenberg-type indicator values by Tichý et al. (2023) and the Ecological Indicator Values for Europe (EIVE) 1.0 by Dengler et al. (2023). The new systems seem to match an urgent need, as both papers are within the top 1% most cited papers of the year 2023 according to the Scopus database.

Four different weighting approaches in comparison. No cover weighting (i.e. either presence-absence or inverse niche-width weighting) gave significantly better results than cover weighting, while square-root cover weighting was intermediate (from the paper)

With 14,835 valid taxa, EIVE is more comprehensive than Tichý et al. (2023) with 8,679 valid taxa, and it also has a larger spatial coverage (for a brief comparison of both systems, see https://vegsciblog.org/2023/01/21/eive-1-0/). Other than that, it was largely unknown which of the two systems performs better and how their performance relates to the performance of regional EIV systems. Only Dengler et al. (2023) contained correlations of species temperature indicators with GBIF-derived temperature niches, which indicated that EIVE performs slightly better than Tichý et al. (2023) and clearly better than most of the regional EIV systems.

While comparing different EIV systems became relevant only recently, the question of how to compute mean EIVs from the species’ EIVs was unresolved for ages. Both cover-weighted and unweighted means are widespread in the literature but without clear arguments, let alone empirical support for one of the solutions (see the review by Diekmann 2003). One could also think of an intermediate solution like square-root cover weighting. Recently, Hájek et al. (2020) proposed inverse niche-width weighting and found that, in certain scenarios, it outperforms other weighting approaches.

In this study, we used three regional datasets of vegetation plots combined with in-situ measured pH values and near-surface annual temperatures, respectively. We used the two European EIV systems (Dengler et al. 2023; Tichý et al. 2023) and the two regional EIV systems applicable for the Swiss Alps (Ellenberg et al. 1991; Landolt et al. 2010). We combined them with four different weighting approaches, namely unweighted (presence), square-root cover weighted, cover weighted and inverse niche-width weighted, the latter only being applicable to “EIVE” and “Landolt”. The performance of the different combinations was assessed via Pearson’s correlation coefficients (r) between mean EIV values and actual site conditions.

The three-national Master Summer School “Biodiversity Monitoring” 2023 in the Swiss regional nature park “Ela” (Photo: Jürgen Dengler)

The first important observation was that – after taxonomic matching – only EIVE contained all valid taxa of the study, whether they were subspecies, species or aggregates, while the three other systems missed a significant number of valid taxa, either completely or by presenting them only at a higher or lower taxonomic level. In the latter cases, an approximative manual assignment would be, of course, possible, but it comes with additional work and arbitrariness. Moreover, while EIVE provides indicator values for all included taxa, just with different niche widths, the other three systems consider many taxa as indifferent and thus do not rate them. These aspects combined meant that dependent on the EIV system and the indicator, the three systems other than EIVE could not use between 12% and 40% of all occurring taxa for the calculation of mean indicator values.

When it comes to predicting site conditions, expectedly all four EIV systems can do that with only moderate differences in mean r values. However, when calculated with EIVE, the correlations were significantly better than when using “Tichý”. By contrast, “Ellenberg” and “Landolt” did not differ significantly from EIVE. Considering the weighting approach, no weighting performed significantly better than cover weighting, while square-root cover weighting was intermediate. In those two EIVE systems that provide niche-width information, no weighting and inverse niche-width weighting were equally good.

Some of the authors sampling a vegetation plot during the Summer School in an subalpine grassland (Photo: Jürgen Dengler)

Our partly unexpected results might be explained by the “wisdom of the crowd” principle, according to which estimates averaged over several independent sources give better results than the assessment by a single good expert (Galton 1907; Surowiecki 2004). Accordingly, EIVE values based on 31 EIV systems should be better than Ellenberg-type indicator values, which are based on 12 EIV systems. Likewise, applying no cover-weighting means that effectively more taxa enter into the mean EIV value.

For the practice of vegetation ecologists in Europe, our study suggests that one should definitely not use full cover-weighting. EIVE or well-established regional EIV systems can be used, but the system of Tichý et al. (2023) is less advisable. Evidently, our study was based on three relatively small samples collected in the very centre of Europe and only for two indicators. It would be important to conduct similar “calibration” studies also in other parts of Europe (or across the entire continent) and for the other indicators. Finally, it is worth mentioning that currently the preparation of EIVE 1.5 is in the final stages, which will contain more than 20,000 valid taxa.

Measuring soil pH in front of the Sonnenhof in Preda, where the Summer School took place (Photo: Jürgen Dengler)

The idea for this paper originated from the initial work on a project conducted as part of the Swiss-Polish-Ukrainian Master Summer School “Biodiversity Monitoring” in Switzerland, during which students could learn about the vegetation ecology of alpine habitats, improve their understanding of statistical concepts, and admire the undeniable beauty of the Swiss Alps. During the 10 days spent in Preda, Switzerland, we sampled vegetation plots and analysed soil pH, which, together with data from previous conductances of the class, laid the foundation for this paper. Despite the relative lack of experience, working under proper supervision and applying newly acquired skills from the Summer School helped further develop this idea and turn it into a proper scientific article.

The statistical principle of the “wisdom of the crowd” suggests that a larger group of people can collectively make better decisions than a smaller one of a few experts. Involving as many researchers as possible in the scientific process, even inexperienced students or young researchers, can help to innovate and create new solutions.

Original study

Ostrowski G, Aicher S, Mankiewicz A, Chusova O, Dembicz I, Widmer S, Dengler J (2025) Mean ecological indicator values: use EIVE but no cover-weighting. Vegetation Classification and Survey 6: 57-67. https://doi.org/10.3897/VCS.134800

References:

  • Dengler J, Jansen F, Chusova O, Hüllbusch E, Nobis MP, Van Meerbeek K, Axmanová I, Bruun HH, Chytrý M, … Gillet F (2023) Ecological Indicator Values for Europe (EIVE) 1.0. Vegetation Classification and Survey 4: 7–29. https://doi.org/10.3897/VCS.98324; see also https://vegsciblog.org/2023/01/21/eive-1-0/ 
  • Diekmann M (2003) Species indicator values as an important tool in applied plant ecology – a review. Basic and Applied Ecology 4: 493–506.
  • Ellenberg H, Weber HE, Düll R, Wirth V, Werner W, Paulißen D (1991) Zeigerwerte von Pflanzen in Mitteleuropa. Scripta Geobotanica 18: 1–248.
  • Galton, F. (1907) Vox populi. Nature 75: 450–451.
  • Hájek M, Dítě D, Horsáková V, Mikulášková E, Peterka T, Navrátilová J, Jiménez-Alfaro B, Tichý L, Horsák M (2020) Towards the pan-European bioindication system: Assessing and testing updated hydrological indicator values for vascular plants and bryophytes in mires. Ecological Indicators 116: 106527. https://doi.org/10.1016/j.ecolind.2020.106527
  • Landolt E, Bäumler B, Erhardt A, Hegg O, Klötzli F, Lämmler W, Nobis M, Rudmann-Maurer K, Schweingruber FH, … Wohlgemuth T (2010) Flora indicativa – Ökologische Zeigerwerte und biologische Kennzeichen zur Flora der Schweiz und der Alpen. 2nd ed. Haupt, Bern, CH, 378 pp.
  • Surowiecki, J. (2004) The wisdom of crowds. Doubleday, New York, US, 336 pp.
  • Tichý L, Axmanová I, Dengler J, Guarino R, Jansen F, Midolo G, Nobis MP, Van Meerbeek K, Attorre F., … Chytrý M (2023) Ellenberg-type indicator values for European vascular plant species. Journal of Vegetation Science 34: e13168. https://doi.org/10.1111/jvs.13168

Spider-eating spiders: new ‘pirate’ species discovered in China

Also known as cannibal spiders, two new species have been discovered in Guizhou Province.

China’s Guizhou Province has long been known for its remarkable biodiversity, but a recent study in Zoosystematics and Evolution has shed light on some of its creepier, lesser-known inhabitants: pirate spiders. 

What is a pirate spider?

The name ‘pirate spiders’ refers to species belonging to the family Mimetidae. Also known (misleadingly) as cannibal spiders, they earned their name because of their araneophagic (spider-eating) nature. 

  • Images of spiders ambushing and eating other spiders.

These eight-legged predators don’t spin webs to catch prey; instead, they infiltrate the webs of other spiders and mimic the vibrations of prey or potential mates, then ambush the unsuspecting hosts when they come to investigate.

A recent research paper by Zhang et al. offers the most comprehensive survey to date of the pirate spider genus Mimetus in Central Guizhou, including two new species, bringing the provincial total to eight and giving Guizhou the highest Mimetus diversity in China.

China’s new species

Mimetus guiyang

Discovered in Guiyang City, this species is known only from females collected via pitfall traps. Its most distinctive feature is the presence of large bubble-shaped ossified hair bases on the abdomen, a rarity among known Mimetus species. Its genital morphology and body patterns make it easily distinguishable from close relatives.

Mimetus lanmeiae

Also found in Guiyang, this species was observed perched on a spider web, likely in the act of mimicry. Its unique palpal structures and small body size (~2.14 mm) distinguish it from other known Mimetus species. The name of the species honours the mother of the specimen collector. Hopefully this was meant as a compliment.

Other findings

  • New records: The researchers recorded two previously known species (M. caudatus and M. sinicus) for the first time in Guizhou, expanding their known range.
  • Rediscovery and redescription: M. caudatus, previously known only from male specimens, now has its female described in detail.
  • Molecular insights: DNA barcoding (COI gene sequencing) was used to support species identification and match males and females – a critical step for accurate taxonomy, especially given the subtle differences between males and females in Mimetus.

Original source

Zhang J, Zhang H, Liu J, Yu H, Xu X (2025) A survey of mimetid spiders (Araneae, Mimetidae) from Central Guizhou Province, China. Zoosystematics and Evolution 101(2): 711-734. https://doi.org/10.3897/zse.101.146895

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High school students replicate insect study from 40 years ago

The goal was to examine how the carrion beetle population has changed over the years.

Over forty years ago, Menno Schilthuizen, while still a high school student, conducted a study on carrion beetles at the Lichtenbeek estate near Arnhem. Using small traps baited with meat and other attractants, he recorded over a thousand beetles in the spring of 1982, meticulously documenting the species and their numbers.

Four decades on, Schilthuizen (now a professor of evolution and biodiversity at Leiden University) and his team collaborated with high school students from the Thomas a Kempis College in Arnhem to replicate the study with precision: at the same location, using the same methods, on the same dates. The goal was to examine how the carrion beetle population has changed over the years. Their findings have been published in the Biodiversity Data Journal; the article can be viewed online here.

A photo of three people doing research in a lush green forest, with one kneeling on the ground and others examining a device.
Fieldwork.

Key findings: shifts in biodiversity

The high school students analysed the beetles that they collected. Their research revealed that some carrion beetle species have disappeared, while other, new species have appeared. However, the overall number of species and population densities have remained largely the same.

One striking discovery was that common species have become even more abundant, while rare species have become even rarer. This widening gap in species commonness suggests a decline in biodiversity, which could signal the potential local extinction of the rarer species.

A citizen science initiative

The research was initiated by the Taxon Foundation, a nonprofit set up and headed by Schilthuizen, in collaboration with biology teacher Leonie Wezendonk of the Thomas a Kempis College. Taxon foundation specializes in biodiversity research conducted by school children, local residents, and other community scientists. The project was made possible through funding from the Netherlands Cultuurfonds and the Suzanne Hovinga Foundation.

Research article:

Schilthuizen M, van der Sterren T, Kersten I, Groenhof M, van der Meulen H, Wezendonk L (2025) Resampling a carrion beetle fauna after 40 years (Coleoptera, Staphylinidae, Silphinae, and Leiodidae, Cholevinae). Biodiversity Data Journal 13: e151206. https://doi.org/10.3897/BDJ.13.e151206

More than 20 journals published by Pensoft with their own hosted data portals on GBIF to streamline and FAIR-ify biodiversity research

The portals currently host data on over 1,000 datasets and almost 325,000 occurrence records across the 25 journals.

In collaboration with the Global Biodiversity Information Facility (GBIF), Pensoft has established hosted data portals for 25 open-access peer-reviewed journals published on the ARPHA Platform.

A screenshot featuring a close-up of a turtle on a forest floor, overlayed with a web portal design for biodiversity data browsing.
A screenshot of the Check List data portal.

The initiative aims to make it easier to access and use biodiversity data associated with published research, aligning with principles of Findable, Accessible, Interoperable, and Reusable (FAIR) data.

The data portals offer seamless integration of published articles and associated data elements with GBIF-mediated records. Now, researchers, educators, and conservation practitioners can discover and use the extensive species occurrence and other data associated with the papers published in each journal.

A video displaying an interactive map with occurrence data on the BDJ portal.

The collaboration between Pensoft and GBIF was recently piloted with the Biodiversity Data Journal (BDJ). Today, the BDJ hosted portal provides seamless access and exploration for nearly 300,000 occurrences of biological organisms from all over the world that have been extracted from the journal’s all-time publications. In addition, the portal provides direct access to more than 800 datasets published alongside papers in BDJ, as well as to almost 1,000 citations of the journal articles associated with those publications.  

“The release of the BDJ portal and subsequent ones planned for other Pensoft journals should inspire other publishers to follow suit in advancing a more interconnected, open and accessible ecosystem for biodiversity research,” said Dr. Vince Smith, Editor-in-Chief of BDJ and head of digital, data and informatics at the Natural History Museum, London.

“The programme will provide a scalable solution for more than thirty of the journals we publish thanks to our partnership with Plazi, and will foster greater connectivity between scientific research and the evidence that supports it,” said Prof. Lyubomir Penev, founder and chief executive officer of Pensoft.

On the new portals, users can search data, refining their queries based on various criteria such as taxonomic classification, and conservation status. They also have access to statistical information about the hosted data.

Together, the hosted portals provide data on almost 325,000 occurrence records, as well as over 1,000 datasets published across the journals.

Everything (in museums) Everywhere, All at Once

Guest blog post by Julia Sigwart.

Imagine walking into a museum and realising that every specimen—a rare deep-sea snail, a giant fossil bone, a pressed plant, the DNA bank, endless drawers of perfectly pinned insects, even the notebooks and dusty photographs in the archive—is part of a vast, interconnected web of knowledge. Now, imagine if all of these specimens—across every museum in the world—were seamlessly linked, their data unified and accessible to scientists, historians, educators, and conservationists everywhere. This vision is at the heart of collectomics—a groundbreaking new term introduced in a recent paper published in Natural History Collections and Museomics.

Examples of natural history objects.
Top: for more than 200 years, relevant object information was most often recorded in the form of hand-written labels and inventories. Bottom: Natural history museums directly intersect with social sciences, although the connections often go unrecognised. Top left: Jan-Peter Kasper/Universität Jena, Top right: Sigrid Hof / Senckenberg Research Institute and Museum Frankfurt, Bottom left: image of Dr Fritz Haas (seated) and unnamed companions (men and women), in the act of collecting a new species Unio valentinus, Bottom right: natural history objects also appear in the context of art objects, photo: Emőke Dénes.

What is Collectomics, and Why Does It Matter?

At its core, the collectomics concept represents a holistic modern view of museum collections. This is not only about digitising collections, or about preserving species; rather this new approach shifts the perspective to treating collections as a single global dataset. Museums represent a dynamic and growing resource that can help answer some of the most pressing challenges in science and conservation. With the integration of digital tools, standardized data practices, and a commitment to open accessibility, collectomics offers a way to transform fragmented collections into a powerful, collective resource that also integrates the cultural and historical aspects of museum collections.

Collectomics envisions museums as interconnected nodes in a worldwide network, rather than isolated repositories of knowledge, and holds this ambition as the primary goal of collections digitisation. This framework allows researchers to trace the movement of species, monitor environmental changes over time, and predict future ecological shifts with greater accuracy. More importantly, it connects beyond the realm of natural sciences to other disciplines. Natural history specimens are objects that were collected by people—including often-uncredited local knowledge holders.

The accessory information about the life and work of those human facets informs our use of museum objects. For example, if we can identify the handwriting on an original collection label, the lifetime of that person can constrain the collecting date even if it was not written down, and this adds to the biological knowledge about the specimen. Conversely, the types of objects and observations recorded by a person inform the understanding of the historical context.

For an increasingly diverse range of scientists, museum data contribute to work without actually depending on physically examining the original objects. They can analyse high-resolution images, genetic data, and historical records without leaving their own labs. Collectomics puts the original objects as the centre of gravity, acknowledging that preserved specimens  underpin the scientific replicability of this rapidly growing suite of applications. 

Natural history museum collection.
Natural history collections are iconic in biodiversity research and yet much of their potential impact remains untapped. Photograph by Sven Tränkner, Senckenberg Museum Frankfurt, Germany.

Looking Ahead: How Collectomics Can Shape the Future

Beyond envisioned technical advancements, collectomics is fundamentally about people. It is about the researchers who dedicate their lives to studying biodiversity, the curators who meticulously preserve specimens, and the students who might one day make groundbreaking discoveries using these collections.

A database is more than just a digital version of a collection—it is structured, searchable, and interconnected, allowing for new patterns and insights to emerge. Physical collections, like a library, must follow a particular a priori organisation. Books on a shelf might be arranged by subject, author, the colour of the dustjacket, or just the order they were unpacked. Zoological and botanical collections are typically arranged taxonomically, while geological collections are organised stratigraphically. And just like running your eyes across a bookshelf, physically browsing a collection often turns up serendipitous inspiration and discovery. Once specimens and their associated data are digitised, different kinds of unexpected relationships and trends can be uncovered. In a collection organised based on systematics, it is almost impossible to answer simple geographical questions like “How many specimens do you have from Malaysia?” because the relevant material is scattered across countless diverse taxonomic groups. The power of digitisation is enabling cross-cutting queries, on geography, time, and the activities of human contributors. This does not replace the need for well organised, well maintained physical collections, but instead unlocks the full potential.

Graph showing the great extent to which records are undigitised.
Digital records are only a small fraction of global museum records. The black line represents a linear increase of the number of collection objects in time from the late 1700s. The dashed lines show three model projections for digitisation: in the best-case model prediction, museums might achieve complete digitisation at the earliest around the year 2071, but if there is no acceleration (red line) the global digitisation gap will continue to increase.

The importance of collections digitisation has long been recognised. However, this has progressed in a patchwork of small projects, often funded for specific research interests. As collections are continuously growing, the rate of growth may be outpacing even modern digitsation efforts. Collectomics offers an outlook that depends on, and also motivates, a total-collections approach. The power of collectomics emerges only when it is applied to everything, everywhere, in interconnecting museum collections including natural history and beyond.

By making collections more accessible, collectomics also contributes to democratising and diversifying science. Historically, access to rare specimens was limited to those with the resources to travel or with institutional connections. But with a collectomics approach, a high school student in a small town can study the same butterfly as a leading entomologist at a major university. A researcher in the Global South can contribute just as meaningfully to biodiversity studies as someone in the Global North. By embracing this new framework, museums are not only preserving history—we are unlocking its full potential.

Original source

Sigwart JD, Schleuning M, Brandt A, Pfenninger M, Saeedi H, Borsch T, Häffner E, Lücking R, Güntsch A, Trischler H, Töpfer T, Wesche K, Consortium C (2025) Collectomics – towards a new framework to integrate museum collections to address global challenges. Natural History Collections and Museomics 2: 1-20. https://doi.org/10.3897/nhcm.2.148855

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Life on Mars? Lichens survive Martian simulation

Previously presumed uninhabitable, the Martian surface may be suitable for certain lichen species.

A thin atmosphere, freezing temperatures, and a barrage of radiation: the surface of Mars is hardly a prime holiday destination. But can any life survive there?

Known for their extreme tolerance to harsh environments such as Earth’s deserts and polar regions, lichens have long been considered a leading candidate for Martian survival. And, for the first time, researchers have demonstrated that certain species can survive Mars-like conditions, including exposure to ionising radiation, while maintaining a metabolically active state.

Published in the open-access journal IMA Fungus, a new study highlights the potential for lichens to survive and function on the Martian surface, challenging previous assumptions that the planet is uninhabitable.

Annotated design showing the set up of the experiment subjecting lichens to Mars-like conditions.
Experiment arrangement of vacuum chamber with the additional facility, including metal grate with lichens, cooling table, temperature, pressure and humidity sensors, X-ray lamp with the controller, CO2 valve with cylinder, controllers of vacuum chamber, pressure, cooling table, and computer.

But what exactly are lichens? It’s a little complicated. In fact, lichens are not a single organism, but rather a symbiotic association between a fungus and algae and/or cyanobacteria.

In this study, the fungal partner in lichen symbiosis remained metabolically active when exposed to Mars-like atmospheric conditions in darkness, including X-ray radiation levels expected on Mars over one year of strong solar activity.

Macro photograph of a lichen species.
Cetraria aculeata.

The research focuses on two lichen species (yes, there are lichen species despite them being a symbiosis), Diploschistes muscorum and Cetraria aculeata, selected for their differing traits. The lichens were exposed to Mars-like conditions for five hours in a simulation of the planet’s atmospheric composition, pressure, temperature fluctuations, and X-ray radiation.

The findings suggest that lichens, particularly D. muscorum, could potentially survive on Mars despite the high doses of X-ray radiation associated with solar flares and energetic particles reaching the planet’s surface. These results challenge the assumption that ionising radiation is an insurmountable barrier to life on Mars and set the stage for further research on the potential for extraterrestrial microbial and symbiotic survival.

“Our study is the first to demonstrate that the metabolism of the fungal partner in lichen symbiosis remained active while being in an environment resembling the surface of Mars. We found that Diploschistes muscorum was able to carry out metabolic processes and activate defense mechanisms effectively. 

“These findings expand our understanding of biological processes under simulated Martian conditions and reveal how hydrated organisms respond to ionizing radiation – one of the most critical challenges for survival and habitability on Mars. Ultimately, this research deepens our knowledge of lichen adaptation and their potential for colonizing extraterrestrial environments.”

Lead author of the paper, Kaja Skubała.

Further long-term studies investigating the impact of chronic radiation exposure on lichens have been recommended, as well as experiments assessing their survival in real Martian environments. 

Researchers from Jagiellonian University and the Space Research Centre of the Polish Academy of Sciences conducted the study with support from the National Science Centre, Poland, and the “Excellence Initiative – Research University” at the Faculty of Biology, Jagiellonian University.

Original study

Skubała K, Chowaniec K, Kowaliński M, Mrozek T, Bąkała J, Latkowska E, Myśliwa-Kurdziel B (2025) Ionizing radiation resilience: how metabolically active lichens endure exposure to the simulated Mars atmosphere. IMA Fungus 16: e145477. https://doi.org/10.3897/imafungus.16.145477

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Exquisite but endangered: new ‘fairy lantern’ flower discovered in Malaysia

The tiny new Thismia species is threatened by habitat degradation.

Species belonging to the genus Thismia are some of the strangest and most magical-looking in the plant kingdom, which has earned them the nickname ‘fairy lanterns.’

No exception to the rule, a newly discovered Thismia species from eastern Peninsular Malaysia looks like something that belongs in a fantasy world.

Take a look below.

Thismia aliasii.

Standing just 11 cm tall, Thismia aliasii is an easy-to-miss and Critically Endangered new species described in the open-access journal PhytoKeys.

The genus Thismia consists of plants that are mycoheterotrophic, meaning they do not photosynthesise and instead rely entirely on fungi for their nutrition. The unusual flowers seen on Thismia species facilitate specialised pollination mechanisms involving small insects such as fungus gnats.

Thismia aliasii was first documented by co-author Mohamad Alias Shakri in 2019 during a field expedition in Terengganu’s Chemerong Forest Eco Park, not far from a hiking path.

“The discovery of Thismia aliasii is very interesting as it was found in a mountainous region known for its natural beauty. The discovery was made on the edge of a popular mountaineering trail, but, remarkably, the species was first recognised by Alias.

“It was not easy to obtain specimens for further study as its habitat is on the mountain and COVID time delayed search efforts. Fortunately, targeted field work to find this plant was successful with the support of NAGAO.”

Siti-Munirah Mat Yunoh, co-author of the paper.

Thismia aliasii is provisionally classified as Critically Endangered (CR) under the IUCN Red List criteria, with only five individuals observed across multiple surveys. The primary threats to its survival stem from habitat degradation due to increasing hiking activities in the region.

This discovery adds to Terengganu’s reputation as a hotspot for Thismia diversity, being home to 13 species of the genus, including six endemics. 

Siti-Munirah Mat Yunoh, Forest Research Institute Malaysia, and Mohamad Alias Shakri, Terengganu Forestry Department completed the research with funding from the Ministry of Natural Resources and Environmental Sustainability under the 12th Malaysian Plan and support from the Nagao Research Grant.

Original source

Siti-Munirah MY, Mohamad Alias S (2025) Thismia aliasii (Thismiaceae), a new species from Terengganu, Peninsular Malaysia. PhytoKeys 254: 175-188. https://doi.org/10.3897/phytokeys.254.136085

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Guest blog post: Global change, individual behaviour, and trout population persistence

New experiments reinforce that behavioural plasticity can be key for coping with environmental changes

Guest blog post by Daniel Ayllón and Steve Railsback

Early in the morning, Daniel Ayllón and his research mates at the Universidad Complutense de Madrid drive towards the mountains near Madrid. They’re out to survey streams where the endangered Southern Iberian spined-loach and Northern Iberian spined-loach used to coexist. We say “used to,” because once again they fail to find the Northern Iberian spined-loach, probably locally extinct. Such extinctions are not unusual, as freshwater fishes are one of the most threatened groups of animals in the world. There are still many brown trout there, though; the water is still cold enough for them.

Salmonids (trout, salmon and char) are especially challenged by climate change because they need cold, oxygenated and clean water. Trout populations at low altitudes or low latitudes are thus particularly at risk; many in the Iberian Peninsula have been declining for decades as rivers warm and dry. Climate models project a bleak future: such Mediterranean populations will face hotter and drier streams, with more frequent and longer droughts and heat waves, and increasing competition from warm-water fish.

A photo of a brown trout swimming over a bed of smooth pebbles in clear water.
Brown trout (Salmo trutta). Photo by J. R. Pérez (AEMS-Ríos con Vida archive)

Despite these changes, local extinctions of trout are still rare, because salmonids are among the most adaptable and resilient of freshwater fishes. They are changing their physiology and phenology, growth and reproduction patterns, and life-history strategies to adjust to the new environmental conditions, via evolutionary, plastic and behavioural mechanisms. While evolutionary ecologists typically focus on genetic adaptation to forces such as climate change, behavioural plasticity could be even more important, because it is fast, reversible and often predictable.

In fact, thermoregulatory movements seem a ubiquitous behavioural mechanism in salmonids: individuals move up and down river networks to find less-stressful temperatures and better growth potential. Behavioural plasticity in circadian activity and habitat selection (deciding when and where to feed) also help trout resist short-term environmental changes. However, we don’t know how important changes in circadian activity─or behaviours in general─are to long-term population persistence in the face of climate change. So to shed light on this question, in a recent work published in Individual-based Ecology, we ran two virtual experiments using the inSTREAM individual-based model to represent a trout population in northern Spain.

A photo of a river flowing between rocky banks, surrounded by greenery and towering mountains under a clear sky.
The Roncal study site on the River Eska (northern Spain). Photo by Benigno Elvira

Steve Railsback and his colleagues at Cal Poly Humboldt University and the US Forest Service’s Pacific Southwest Research Station in Arcata, California, have been developing, testing, and applying inSTREAM for 25 years. The central idea of individual-based models (IBMs) and of individual-based ecology in general is that a biological system can be described through its individual agents, their environment, and the interactions among agents and between agents and environment. The agents of a system (for example, all fish in a population) are modelled as unique and autonomous individuals with their own properties.

The controlled experiment of Harvey and White to quantify how trout trade off feeding vs. predation risk. The experimenters trained wild trout to feed at this dispenser, and then moved it to increasingly risky habitat. The feeding rate needed to keep the trout from leaving increases with the risk it perceives. IBMs like inSTREAM use knowledge about individual behaviour from experiments like this to predict complex population responses. Video by Jason L. White.

Agents also have behaviours: they make decisions, following simple rules or algorithms, independently of other individuals, and seek objectives such as surviving to reproduce in the future. These behaviours are adaptive: agents’ decisions depend on their state and the state of their environment. In this way, population-level results actually emerge from the behaviour of the individuals. In inSTREAM, model trout decide whether to feed vs. hide from predators at different times of day, assumed a trade-off between the need to feed and the predation risk it poses. Temperature has a strong effect on this trade-off because a fish’s metabolic rates, and thus the amount of food it needs, increase sharply with temperature.

A photo of three people wearing waders engaged in field research in a river.
Three members of the research team at the UCM conducting habitat surveys at the Roncal study site. In IBMs like inSTREAM, modelled populations and their environment are characterised by field data collected in surveys like this. Photo by Benigno Elvira.

What did we learn with our IBM? First, our simulations show what behavioural ecologists know from experiments: that during warm summers trout can meet their metabolic requirements only by feeding at multiple times of day and segregating temporally, so that fish of different size can feed at the same spot but at different times of day. Feeding during daytime is more profitable but riskier, while doing it at night is safer but less efficient, and feeding during twilight provides near-daytime growth and somewhat-reduced risk.

We then analysed how model trout change their circadian foraging behaviour under increasing climate change. As we expected, trout showed great behavioural plasticity: trout of all ages responded to warmer and drier conditions by increasing daytime feeding and overall foraging activity, although there were differences across age classes in the distribution of daily activity. Our second experiment used a great advantage of IBMs as a virtual laboratory: we can run experiments that are impossible in reality. We tested the importance of behavioural plasticity by simply turning the behaviour off. In our simulations, virtual populations of trout capable of flexible circadian feeding were more resistant to climate change─had higher biomass and a more balanced age structure─than were populations of trout that feed only during daytime.

These experiments reinforce that behavioural plasticity can be key for coping with environmental changes, so we shouldn’t minimise its relevance when predicting the persistence of salmonid populations in warming and drying rivers. This conclusion no doubt also applies to other taxa that have powerful adaptive behaviours.

This study epitomises individual-based ecology, the subject of Pensoft’s new journal: we use what we know from empirical research on individual physiology and behaviour, in an individual-based model, to study complex population responses of direct relevance to our changing world.

Research article:

Ayllón D, Railsback SF, Harvey BC, Nicola GG, Elvira B, Almodóvar A (2025) Behavioural plasticity in circadian foraging patterns increases resistance of brown trout populations to environmental change. Individual-based Ecology 1: e139560. https://doi.org/10.3897/ibe.1.e139560

Recently launched Individual-based Ecology journal publishes its first articles

IBE offers a transformative framework for addressing global challenges such as the loss of biodiversity and potential loss of ecosystem services.

Individual-based Ecology (IBE), a new open-access peer-reviewed journal by scholarly publisher and technology provider Pensoft, has now published its first articles, offering a fresh perspective on how the behaviour of individual organisms and ecological systems dynamics are linked.

The journal was launched in September 2024 with an official announcement made during the German Ecological Society’s 53rd annual conference (Freising, Germany).

To fill a known gap in knowledge, the journal focuses on individual-based perspectives in ecology, complementing other ecological disciplines. Current approaches cannot fully capture the mechanisms underlying ecological responses to change in drivers, the journal’s editors believe, as they rarely focus on the individual organisms who directly respond to change.

Four editors-in-chief lead IBE: Prof. Dr. Volker Grimm and Prof. Dr. Karin Frank of Helmholtz Centre for Environmental Research – UFZ, Prof. Dr. Mark E. Hauber of The City University /(CUNY) of New York, and Prof. Dr. Florian Jeltsch of the University of Potsdam. “This team represents an international and collaborative group who agree on the conceptual and empirical need for this new journal”- says Dr Mark E. Hauber, from the Graduate Center of CUNY, and a former guest professor in ecology at the University of Potsdam.

The journal is published under a diamond open-access model, which makes it free of charge for both readers and authors. It publishes a wide range of articles, including empirical, experimental, and modeling studies, as well as reviews, perspectives, and methodological papers.

By blending basic and applied research, IBE offers a transformative framework for addressing global challenges such as the loss of biodiversity and potential loss of ecosystem services.

“We propose a paradigm shift in ecological science, moving from simplifying frameworks that use species, population or community averages to an integrative approach that recognizes individual organisms as fundamental agents of ecological change,” advocates write in a forum paper just published in IBE’s first issue. 

Illustration showing mouse behavior variation, predation effects, and colonization success based on boldness and size in new habitats.
Examples of individual variation and its consequences: a individual variation describes the variation in traits, including behaviour, between or within individuals resulting from various processes such as microevolution and biotic filtering. It also explicitly includes variation induced by experience, health status or microbes and microbial communities associated with the host; b simplified example showing how successful colonisation or invasion depends on inter-individual variation in morphological or behavioural traits (González-Suárez et al. 2015; Dammhahn et al. 2020; Premier et al. 2020).

“By unravelling and predicting the dynamics of biodiversity in the Anthropocene through a comprehensive study of individual organisms, their variability and their interactions, individual-based global change ecology will provide a critical foundation for a better understanding if and how we can manage individual variation and behaviour for conservation and sustainability, taking into account individual-to-ecosystem pathways and feedbacks.” 

Illustration showing the impact of individual variation on biodiversity across genes, populations, communities, and ecosystems under global change.
Hierarchical organisation from genes to ecosystems. Individuals are the elementary particles of ecological systems, meaning that variation and interactions between individuals can scale up to emergent properties at the population, community and ecosystem levels. The different ecological levels are highly interconnected through both bottom-up and top-down processes. Elucidating these feedback loops through an individual-based lens is a prerequisite for understanding ecosystem resilience and response to global change.

“By taking into account the variation, behaviours, and interactions of individual organisms, individual-based ecology links the responses of organisms to the responses of ecosystems: if we understand enough about individuals, we can predict complex system dynamics, even under novel conditions,” the editors and colleagues write in a “manifesto” for individual-based ecology that they published in the new journal. “We intend the journal to show how the individual-based perspective, in empirical, theoretical, and computational studies, benefits all branches of ecology.”

IBE’s first published research articles provide excellent examples of the individual-based perspective of the journal. Church et al. explore, using an established model of brown trout, how the uptake of microplastics by fish with different personalities affects population size. Ayllón et al. use the same model to explore to what extent behavioural plasticity allows this species to cope with environmental change, in particular increasing temperatures. Railsback and Harvey argue that in many models the representation of mortality risk is too simple. They present a new method, “survival increase functions”, which is more realistic but still straightforward to calibrate. 

The journal is supported by the Helmholtz Centre for Environmental Research (UFZ, Germany) and the City University of New York (CUNY, USA).

The journal utilises Pensoft’s innovative ARPHA platform, which offers a seamless end-to-end publishing experience, encompassing all stages between manuscript submission and article publication, indexation, dissemination and permanent archiving. As a journal of Pensoft, IBE joins a number of open-access scholarly outlets in ecology  by the publisher.

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You can keep up with updates from the journal on Bluesky, X and Facebook.

New smartphone workflows revolutionize the digitization of natural history collections

By digitizing these data, we can preserve valuable knowledge about our biodiversity, especially in times of climate change and biodiversity crises.

A team from the Leibniz Institute for the Analysis of Biodiversity Change (LIB) has discovered groundbreaking ways for rapidly digitizing collection data. Data of insect specimen labels can now be easily read with just a smartphone – and all wirelessly and using only free, already available apps!

Why is this important?

Around 1.1 billion objects in the largest natural history museums worldwide remain undigitized and manual extraction of specimen label information for taxonomic revisions, another source for biodiversity data mobilization, is very time consuming. By digitizing these data, we can preserve valuable knowledge about our biodiversity, especially in times of climate change and human biodiversity crisis when many species are going extinct before they are even discovered.

This innovation will accelerate and advance global research and the preservation of our biological knowledge. And the best part? It’s not expensive and accessible to everyone – from professionals to amateur scientists!

Research article:

Ahrens D, Haas A, Pacheco TL, Grobe P (2025) Extracting specimen label data rapidly with a smartphone—a great help for simple digitization in taxonomy and collection management. ZooKeys 1233: 15-30. https://doi.org/10.3897/zookeys.1233.140726