The amazing diversity of the Caribbean pygmy jumping leaves

Pygmy grasshoppers come in many shapes and colors and are often exciting to see, but their taxonomy is a mess.

Guest blog post by Josip Skejo & Niko Kasalo

A lovable mess

Tetrigidae, commonly known as pygmy grasshoppers, are an ancient and diverse family, currently numbering about 2000 species. As their name suggests, tetrigids are very small; their largest representatives are barely several centimeters long, so they might be difficult to spot on a casual stroll through tropical vegetation. However, when they are spotted, they are immediately recognizable by their elongated pronotum, a hard structure that starts behind the head and covers the entire body like a hood. They come in many shapes and colors and are often exciting to see, but this comes with a price—the taxonomy of Tetrigidae, the way they are organized into natural groups, is a mess. This is where we come in.

In our latest paper, we dealt with Choriphyllini, a small Caribbean tribe that belongs to the subfamily Cladonotinae. This subfamily had been filling up with unrelated but similar-looking tetrigids for more than a century. It had never been clearly defined so almost everything wingless and robust was assigned to Cladonotinae. We decided to put an end to this by slowly removing the superficially similar genera from the subfamily and describing tribes to group the genera that are clearly related to each other. We piloted this system just last year, when we described the tribe Valalyllini from Madagascar, with only two endemic (and endangered) genera and species.

The diversity and the distribution of the tribe Valalyllini, the Malagasy dead-leaf-like Cladonotinae. Both species are endemic to small areas and are likely endangered because of deforestation. Both species most probably inhabit rainforest leaf litter.

Put the species of Choriphyllini and Valalyllini together, mix them up, and try to guess which belongs where—this is no simple task; they are all doing their impressions of dead leaves that our primate brains struggle to differentiate. And there’s more: such leaf-like grasshoppers live in Africa and South East Asia as well, and then there are those that look like twigs and spiky tree bark.

Only now that we have an idea of what the true Cladonotinae are can we be properly amazed by the duality they represent to us. On the one hand, they are incredibly diverse with every species having its own variation on the basic shape. On the other, they are so alike that they either represent the best example of convergent evolution ever documented or they all stem from a common ancestor that is currently supposed to have lived during the Mesozoic. The evolutionary history of Cladonotinae will take many years to unravel, but the work can only begin after we define what to call by that name.

Valalyllum folium, a member of the tribe Valalyllini, subfamily Cladonotinae. This species, endemic to Madagascar, is a relative of Choriphyllini.

It only took 250 years

The first species of Choriphyllini, Phyllotettix rhombeus, was described in 1765 as Cicada rhombea, that is, as a member of an entirely different order of insects. Continuing in this manner, many authors (including the great Linnaeus himself) made many taxonomic and nomenclatural mistakes that compounded over the centuries and made these grasshoppers difficult to identify and refer to. It didn’t help that new species and new records kept being reported without being contextualized by comprehensive literature reviews. Like detectives, we followed the scattered crumbs of data and arrived at a synthesis that will make future research in the region much more pleasant.

Hancock’s plate I from the “Tettigidae of North America” shows leaf-like Caribbean species under the numbers 1), 2) and 7), but has many taxonomic and nomenclatural errors. 1) – Phyllotettix foliatus (= female holotype of Hancock’s Choriphyllum foliatum), 2) – Phyllotettix rhombeus (= Hancock’s Choriphyllum westwoodi), 7) – Choriphyllum saussurei. (= Hancock’s Phyllonotus saussurei). Source: Biodiversity Heritage Library, available at

This is not where interesting facts about Phyllotettix rhombeus stop. While looking through the literature, we tried to extract the measurements of drawings. Most of the drawings had a scale bar printed next to them, but the archaic usage of “lines” as the standard measurement initially gave us some trouble. That is why at first we doubted one of our most fascinating discoveries: with the pronotal length measuring nearly 3 centimeters, Phyllotettix rhombeus is the largest tetrigid ever recorded! Many, many authors dealt with this species over the last 250 years, but this record was never made explicit.

It should not go unnoticed now that its proposed common name is “Jamaican Colossal Jumping Leaf”. Inspired by this, we took the measurements of the other species as well and made a figure where all the specimens are resized to a common scale, which shows the diversity of both shapes and sizes.

The genera and species of the tribe Choriphyllini. All specimens are drawn to scale.

Besides P. rhombeus, there are three more species in the genus Phyllotettix: P. plagiatus, P. foliatus, and P. compressus. All four of them are known only from Jamaica. P. foliatus and P. compressus are known from the Blue Mountains, but for the other two no precise localities are known; we still don’t know where exactly the largest tetrigid lives. The other genus of the tribe is Choriphyllum, also with four species. Three of them, C. sagrai, C. saussurei, and C. wallaceum live in Cuba, while C. bahamense is all alone on Hummingbird Cay island in the Bahamas. The easiest way to differentiate these two genera is a little strange but practical, the tallest point of the leaf-like crest in Choriphyllum species is in the front, while in Phyllotettix species it is in the back.

A map of all known Choriphyllini records. For three species, not a single precise locality is known.

Some Caribbean leaves dance and jump

For each species, we proposed a common name as a means to give these animals even more character. Names, such as “Jamaican Bitten Jumping Leaf” and “Old Cuban Dancing Leaf” may not be “official”, but they have certainly found their audience. The tweet in which we shared the collage of all the species was viewed over 17000 times; everyone was amazed by the pretty shapes and some even noted that they especially liked the crazy common names. We were very glad to see our scientific and artistic package that is Choriphyllini be so warmly received.

Another hit on Twitter, with over 20000 views, is the post showcasing the newly-described species from Cuba, Choriphyllum wallaceum. The holotype of this species has been awaiting description for a long time. We found it in Museo Nacional de Ciencias Naturales in Madrid, Spain, with a note from Ignacio Bolívar, the father of the Tetrigidae classification system. He referred to it as “Choriphyllum Seoanei” but never managed to publish it.

This “new” species presented us with the perfect opportunity to honor the 200th anniversary of Alfred Russel Wallace’s birth. Wallace is often called the “father of biogeography” but is all too often neglected when discussing the origins of the theory of evolution, with which Charles Darwin is considered synonymous. Wallace, with his independent arrival at the key concepts of the evolutionary theory, his correspondence with Darwin, and his staunch defense of Darwin’s ideas, was (and is) at the very least equal to Darwin and deserves much more recognition than he currently gets.

Choriphyllum wallaceum, a newly-described species from Cuba, named after Alfred Russel Wallace.

This is just the start

Choriphyllini are a pretty package, but one that merely introduces the real problem. The history of this tribe is long, yet we have very few specimens to work with. Although we have an understanding of how morphology varies within species, P. compressus and P. foliatus are not only suspiciously similar to each other, but they also live in the same general area of the Blue Mountains. It remains to be seen if they are in fact a single species.

Much more pressing is that we have only a vague idea of where these animals live and how their populations are impacted by various factors such as human activity and climate change—we do not have a baseline against which to assess their conservation status. Then there is the fact that there are many more islands in the Caribbean, making the possibility of discovering new Choriphyllini species on them real and exciting. We can only guess what the future holds for these neglected animals.

Old Cuban Dancing Leaf (Choriphyllum sagrai) in its natural environment among the leaf litter in Cuba, photographed by Sheyla Yong.

The stage is set; everything we know about this group is laid out in the paper and now there is no path but forward. Research is expensive, dedication to this work takes a certain kind of soul, and everything takes time. It is our sincere hope that someone someday takes this further. The pygmy jumping leaves will wait for as long as they can, on their islands, hopping without a care in the world.


Deranja M, Kasalo N, Adžić K, Franjević D, Skejo J (2022) Lepocranus and Valalyllum gen. nov. (Orthoptera, Tetrigidae, Cladonotinae), endangered Malagasy dead-leaf-like grasshoppers. ZooKeys 1109: 1-15.

Skejo J, Yong S, Bogić D, Kasalo N (2023) Caribbean pygmy jumping leaves (Tetrigidae, Cladonotinae, Choriphyllini). Deutsche Entomologische Zeitschrift 70(1): 129-141.

Tax man turned taxonomist: a citizen scientist’s journey into botany

“I have absolutely no formal training in botany, but now I find myself as a coauthor in the publication of 18 new species in Costaceae.”

Guest blog post by David Skinner

Costus prancei, one of the 18 newly described species in Costaceae.

I am a retired government bureaucrat who worked for 40 years as an administrator in state and federal taxation. I have absolutely no formal training in botany, but now I find myself as an active participant in a major taxonomic revision and a coauthor in the publication of 18 new species in a plant family called Costaceae. This is the story of how my gardening hobby turned into an avocation and led me to work with some of the premier botanists in the world. It is also the story of how I have met several other plant enthusiasts from countries throughout the tropics who have contributed so very much to our work. I write this story in the hopes of encouraging more professional scientists to incorporate the observations of such “citizen scientists” in their research, and to encourage these enthusiasts to more carefully document their observations and post their photos and notes to resources like

My story started about 30 years ago when my wife gave me a rhizome of the white butterfly ginger (Hedychium coronarium) as a Christmas present. I became interested in gingers, species of the family Zingiberaceae, but soon my interests began to focus almost exclusively on the closely related “spiral gingers” in the family Costaceae. I loved the architecture of the plants with their spiral staircase of leaves leading up to a variety of shapes and colors of bracts and flowers. I started collecting any cultivated Costus plants I could find in nurseries or mail-order catalogues. Soon, I learned that only a few species can survive outdoors in the winter where I live, so built a greenhouse.

Costus convexus, one of the 18 newly described species in Costaceae.

My serious interest in Costaceae began after I obtained a copy of the 1972 monograph of New World Costaceae by Dr. Paul Maas. It became my bible.

As I studied his descriptions of the species and applied his identification keys to the cultivated plants, I soon realized that many of the popular Costus species in cultivation had been incorrectly identified. I started doing presentations to garden clubs and posting to online groups. I developed a website called “Gingers ‘R’ Us.”

My “real job” had me traveling to Washington, DC periodically and I always tried to carve out time to visit Mike Bordelon at the Smithsonian Greenhouses in Suitland, Maryland. On one of these trips, I met Dr. Chelsea Specht, who was working at the Smithsonian Institution as a postdoctoral fellow.

Chelsea Specht and Mike Bordelon at the Smithsonian Greenhouses in 2004.

She had written what I believe is the first molecular study in Costaceae in 2001.This opened up a whole new world of interest for me as I tried to understand these new-to-me terms, like “clades” and “phylogenetic relationships”. In this paper she introduced the new generic divisions of the family that were solidified five years later in a more complete phylogenetic study . Chelsea very patiently answered my novice questions about phylogenetic trees and how they relate to the taxonomy of the plants.

Reinaldo Aguilar in 2013 at the type locality of Costus maritimus, now a synonym in the Costus comosus complex.

In 2005 I made my first trip to the New World tropics looking for Costus in its native habitat. On the Osa Peninsula of Costa Rica, I was incredibly lucky to meet Reinaldo Aguilar, the world-famous “para-taxonomist” who has studied the plants of the Osa for over 30 years. He is is self-taught like me and does not have a botanical degree, but has coauthored many scientific articles. He worked closely with the late Scott Mori of the New York Botanical Garden and was honored in a 2017 article in NYBG Science Talk.

That first trip to Costa Rica had me hooked. I fell in love with tropical forests and over the next few years made trips to several other Latin American countries as well as back to Costa Rica. Always, my focus was on Costus and the other members of its family.

Along the way, I met several “unsung heroes” in the plant world,  like Marco Jiménez Villata, whom I met in the town of Zamora in southern Ecuador. Marco specializes in orchids, but he is also a generalist and knows a lot about the plants of southern Ecuador. He (now retired) was a school administrator and had traveled to many remote villages in the province and was always on the lookout for interesting plants. I have traveled with Marco and his son Marco Jiménez León several other times and we have become good friends.

Marco Jimenez and son Marco with Costus convexus.

In 2015 we went to the type locality of the species Costus zamoranus and took the first photographs of this species. At that trip, Marco showed me an area of high elevation near the Podocarpus National Park, where I found an unusual-looking Costus that we are now describing as Costus oreophilus. He also showed me unexplored places where I found another new species, Costus convexus. I made sure we credited him with his role in the discovery and documentation of those new species in our publication in PhytoKeys.

I have also traveled several times in Panama and Ecuador with another very well known, but non-doctorate plant enthusiast – Carla Black. Carla is the president of the Heliconia Society International, an organization uniting enthusiasts (scientists and non-scientists) in the order Zingiberales.

Carla Black with Juan Carlos Amado on the old Camino Real.

In 2015 we searched for the critically endangered Costus vinosus. We found a few plants growing deep in the forest of the Chagres National Park along an old Spanish trail used to transport gold to the Atlantic coast. There is still a mystery regarding the true form of the flower of C. vinosus, and I am in touch with another Inaturalist observer who has found it (not in flower) in the mountains northeast of Panama City. He will let me know when he finds it in flower!

Costus callosus, one of the 18 newly described species in Costaceae.

In 2019 Carla and I visited the “Willie Mazu” site in Panama to photograph and study the new species Costus callosus, and in Santa Fé de Veraguas, we looked for a species proposed by Dr. Maas that is now described as Costus alleniopsis.

My serious collaboration with Dr. Maas began in 2017, when I was preparing for a trip to Oaxaca in southern Mexico. He asked me to be on the lookout for  two species of Costus from that region that he had identified as new based solely on his examination of herbarium specimens, without any good data on the floral parts.

By that time, I was posting my Costus observations on and using that resource to look for interesting plants. I also used it to find plant people to contact for local information. For this Mexico trip I found a huge number of observations posted by Manuel Gutiérrez from Oaxaca City.

Manuel Gutiérrez photographing the plant that turned out to be Costus sepacuitensis.

I found that he had extensive knowledge of the Chinantla region in the mountains east of Oaxaca City and had worked with the indigenous tribe there. Together, we explored the indigenous lands of Santa Cruz Tepetotutla.

We found many plants in flower of what Dr. Maas wanted to describe as Costus alticolus. We also found the species he planned to describe as Costus oaxacus, but I later found the same species in Guatemala, already described as Costus sepacuitensis.

Later I learned of the plans to prepare a complete revision to the taxonomy of the New World Costaceae. Together with Paul and Hiltje Maas, we spent several days at the Naturalis Herbarium in Leiden, comparing my photos against the hundreds of Costus herbarium specimens there. I had a long list of species that was curious about, and we were able to get through it and figure out what questions remained, even though we had not come up with all the answers.

Dave Skinner and Paul Maas discussing some Costus spp. in Leiden in 2017.

It was soon apparent that there are major changes needed in the taxonomy and nomenclature of these plants, and that information from the field would be an essential supplement to the observations made from the herbarium specimens.

Paul and Hiltje Maas in Leiden in 2017.

In 2016 I visited the type locality of Costus laevis in central Peru. I was surprised to find that the plants there are nothing at all like the Costus laevis of Central America, but match perfectly to the herbarium specimen that was deposited in Spain over 230 years ago. It was clear to me that the herbarium specimen designated as the type had been misinterpreted. I wrote an article explaining the problem – but I had no idea what the solution might be.

Dr. Maas agreed that there was a problem with that species that we eventually resolved. This resolution will be a part of the forthcoming revision of the New World Costaceae that is in preparation, nearing completion.

An image of Costus guanaiensis posted by Anthony Batista on on October 27, 2021.

Another major problem involved the Costus guanaiensis complex. Paul and Hiltje, along with Chelsea, had visited the New York Botanical Garden Herbarium, where the holotype of that species is held, and realized that it had been misinterpreted due to the lack of a good flower description. What had been identified as Costus guanaiensis in the herbarium was actually a completely different species that Maas had planned to describe as a new species.

Dave Skinner with a plant in cultivation of Costus gibbosus at Rio Palenque Science Center, Ecuador.

The entire C. guanaiensis complex needed name changes and redefinitions of species boundaries, ultimately resulting in the description of Costus gibbosus that is published in PhytoKeys. The resolution of the other members of that complex will be explained in the forthcoming revision. Over the next several years, Paul and I exchanged 1,626 emails (yes, I counted them – with the help of MS Outlook) pounding out the details of the changes needed in the taxonomy of New World Costaceae. In collaboration with him, I made many more field trips to resolve the remaining questions we had.

My extensive collaboration with Paul Maas has been one of the most rewarding experiences of my lifetime. He has taught me so much about the rules of nomenclature and the process of describing a new species. The one thing he could never teach me was his almost uncanny ability to look at a dried herbarium specimen and make a determination of the species. I suppose that only comes from experience as  he has examined over 11,000 specimens of Costaceae that will become our list of exxicatae when the full revision is published.

I should not fail to mention my time working with Dr. Thiago André. In 2014 I flew to Rio de Janeiro and then Thi and I, along with his academic advisor and another student, went to the state of Espirito Santo to look for the endangered species Chamaecostus cuspidatus. Thi has been our expert in that genus and has helped with the review of the new species published in PhytoKeys, Chamaecostus manausensis. In 2014 he was still finishing his doctorate and was in process of preparing a molecular phylogeny and morphological study of the species complex of Chamaecostus subsessilis.

Thiago André with Chamaecostus cuspidatus in 2014.

Thi and I have stayed in close contact, and he came to Florida one year to visit in my home and see the Costaceae in my private garden, Le Jardín Ombragé. He is now a professor at the Universidade de Brasília.

Finally, I should discuss my collaboration with Eugenio Valderrama and the other members of the Specht Lab at Cornell University. In 2018 I went to Cornell to visit Eugenio and we discussed the sampling to be used in the molecular phylogeny that will be a very important part of the full revision when it is published.

Eugenio Valderrama and Chelsea Specht with Costus convexus.

At Cornell, Eugenio produced a novel baiting schema for extracting specific genes from across all Costus species and in 2020 published a paper. With further sampling, another paper was published in 2022 to reveal interesting data on a whole package of pollination-related characters, and how they show evidence of convergent evolution. Eugenio’s phylogenies very well support the new species we are publishing in PhytoKeys, and the full molecular phylogeny will be included in our full revision when it is published.

Eugenio checking out a Renealmia sp. Antioquia, Colombia 2022.

Just this past December I went to Colombia to attend the Heliconia Society Conference at Quindío, and Eugenio and I each made presentations there about our work with Costaceae. Then we traveled together to investigate several other interesting species of Costaceae, including the new species Costus antioquiensis, and a strange yellow bracted form of Costus comosus found in the species-rich area of San Juan de Arama in Meta.

How did I know to look there? An observer, a citizen scientist, had posted his records and photos on I have my account set to filter all Costaceae and send me a daily email with all the new postings of the family, and this plant will now be appearing as a sample in a molecular phylogeny and as an observed species in a monograph.

I hope this blog article will provide some background and insight into what I think must be an unusual collaboration between a citizen scientist and the much more qualified lead authors of our PhytoKeys article describing eighteen new species in Costaceae. It has certainly been a rewarding experience for me, and I hope other plant enthusiasts will be encouraged to share their observations on forums like, providing detailed and accurate information and photos. At least for the one plant family I have some expertise in, I will continue to monitor and curate those observations on Inaturalist.

 To see all of my own field observations of Costaceae, including the new species we are describing in PhytoKeys, go to


André T, Specht CD, Salzman S, Palma-Silva C, Wendt T (2015) Evolution of species diversity in the genus Chamaecostus (Costaceae): Molecular phylogenetics and morphometric ap­proaches. Phytotaxa 204(4): 265-276.

Maas, P. J. M. (1972). Costoideae (Zingiberaceae). Flora Neotropica 8, 1–139. doi: 10.1093/aob/mch177

Maas PJM, Maas-van de Kamer H, André T, Skinner D, Valderrama E, Specht CD (2023) Eighteen new species of Neotropical Costaceae (Zingiberales). PhytoKeys 222: 75-127.

Salzman S, Driscoll HE, Renner T, André T, Shen S, Specht CD (2015) Spiraling into his­tory: A molecular phylogeny and investigation of biogeographic origins and flo­ral evolution for the genus Costus. Systematic Botany 40(1): 104–115.

Skinner D (2008) Costus of the Golfo Dulce Region. Heliconia Society Bulletin 14(4):1-6

Skinner D and Jiménez M (2015) Costus zamoranus: An endemic species to Zamora-Chinchipe Province in Southeastern Ecuador. Heliconia Society Bulletin 21(3):4-9

Skinner D (2016) Following Ruiz. Heliconia Society Bulletin 22(4): 7–14.

Skinner D and Black C. (2016) Search for the Mysterious Lost Plant (Costus vinosus). Heliconia Society Bulletin 22(3):1-3

Skinner D (2019) A Tale of Two Costus (Costus sepacuitensis) and Costus cupreifolius) Heliconia Society Bulletin 25(1):1-3

Specht CD, Kress WJ, Stevenson DW, DeSalle R (2001) A molecular phylogeny of Costa­ceae (Zingiberales). Molecular Phylogenetics and Evolution 21(3): 333–345.

Specht CD, Stevenson DW (2006) A new phylogeny-based generic classification of Costaceae (Zingiberales). Taxon 55(1): 153–163.

Valderrama E, Sass C, Pinilla-Vargas M, Skinner D, Maas PJM, Maas-van de Kamer H, Landis JB, Guan CJ, AlmeidaA., Specht CD (2020) Unraveling the spiraling radiation: A phylogenomic anal­ysis of neotropical Costus L. Frontiers in Plant Science 11: 1195.

Valderrama E, Landis JB, Skinner D, Maas PJM, Maas-van de Kamer H, Sass C, Pinilla-Vargas M, Guan CJ, Phillips R, Almeida A, Specht CD (2022) The genetic mechanisms underlying the convergent evolution of pollination syndromes in the Neotropical radiation of Costus L.Frontiers in Plant Science 13:

Where did all those insects come from? Tracking the history of insect invasion in Chile

Going through centuries-old literature, researchers compiled a database of the exotic insects established in the country.

Guest blog post by Daniela N. López, Eduardo Fuentes-Contreras, Cecilia Ruiz, Sandra Ide, Sergio A. Estay

Understanding the history of non-native species arrivals to a country can shed light on the origins, pathways of introduction, and the current and future impacts of these species in a new territory. In this sense, collecting this information is important, and sometimes essential, for researchers and decision makers. However, in most cases, reconstructing this history takes a lot of work. Finding antique references is hard work. To add more complexities, changes in the taxonomy of species or groups could be frustrating as we try to track the moment when a species was referenced in the country for the first time, sometimes centuries ago. Of course, we only learned about these issues when, almost seven years ago, we thought that compiling a database for the exotic insects established in Chile would be interesting to people working on invasive species in the country.

Tremex fuscicornis caught in Chile. Photo by Sergio Estay

First, we collected information from physical and electronic books and journals available in our institutional libraries, but soon we noticed that we needed a more significant effort. In Chile, the National Library and The National Congress library allowed us to review and collect information from texts, in many cases, over a hundred years old. We also had to request information from foreign specialized libraries and bookstores. Sometimes, we had to negotiate with private collectors to buy antique books or documents. When we figured the first version of the database was ready, we began a second step for detecting errors, correcting the taxonomy, and completing the information about the reported species.

Ctenarytaina eucalypti individuals and damage in Chile. Photo by Sergio Estay

The analysis began when we finally completed the database. What types of questions could we answer using this data? Was the database complete enough to detect historical, biogeographic, and ecological patterns? Two competing hypotheses were the starting point for the study at this stage. On the one hand, the species that dominated the non-native insect assemblage could have come from original environmental conditions that matched Chile’s. Or, the pool of non-native insects arrived using pathways associated with the country’s economic activities, regardless of their origin.

We found records of almost 600 non-native insect species established in continental Chile. Most species corresponded to Hemiptera (true bugs and scales, among others) from Palaearctic origin and were linked to agriculture and forestry, as we initially hypothesized. These characteristics point to the central role of intercontinental human-mediated transport in structuring non-native insect assemblages in Chile. Non-native insect introductions began immediately after the arrival of Europeans to the central valley of Chile and have shown an enormous acceleration since 1950. Using data on the economic history of Chile, we can preliminary link this acceleration with the strong development in agriculture and forestry in Chile after World War II and the increase in intercontinental air traffic.

Exotic aphids in garden in Chile. Photo by Sergio Estay

The development and analysis of this database gave us some preliminary answers about the ecology of invasive insect species and opened the door to new questions. Also, this is a work in progress. We need the scientific community’s support to improve and correct the records, provide new reports and collect further references to support the database. Our data and analysis may be representative of other countries in South America. Similarities between our countries can facilitate using this information to manage recent introductions and prevent significant economic, social, or environmental damage.


López DN, Fuentes-Contreras E, Ruiz C, Ide S, Estay SA (2023) A bug’s tale: revealing the history, biogeography and ecological patterns of 500 years of insect invasions. NeoBiota 81: 183-197.

EIVE 1.0 – The largest system of ecological indicator values in Europe

EIVE 1.0 is the most comprehensive system of ecological indicator values of vascular plants in Europe to date. It can be used as an important tool for continental-scale analyses of vegetation and floristic data.

Guest blog post by Jürgen Dengler, Florian Jansen & François Gillet

Geographic coverage of the 31 ecological indicator value systems that entered the calculation of the consensus system of EIVE 1.0 (image from the original article).

It took seven years and hundreds of hours of work by an international team of 34 authors to develop and publish the most comprehensive system of ecological indicator values (EIVs) of vascular plants in Europe to date.

EIVE 1.0 is now available as an open access database and described in the accompanying paper (Dengler et al. 2023).

EIVE 1.0 provides the five most-used ecological indicators, M – moisture, N – nitrogen, R – reaction, L – light and T – temperature, for a total of 14,835 vascular plant taxa in Europe, or between 13,748 and 14,714 for the individual indicators. For each of these taxa, EIVE contains three values: the EIVE niche position indicator, the EIVE niche width indicator and the number of regional EIV systems on which the assessment was based. Both niche position and niche width are given on a continuous scale from 0 to 10, not as categorical ordinal values as in the source systems.

Evidently, EIVE can be an important tool for continental-scale analyses of vegetation and floristic data in Europe.

It will allow to analyse the nearly 2 million vegetation plots currently contained in the European Vegetation Archive (EVA; Chytrý et al. 2016) in new ways.

Since EVA apart from elevation, slope inclination and aspect hardly contains any in situ measured environmental variables, the numerous macroecological studies up to date had to rely on coarse modelled environmental data (e.g. climate) instead. This is particularly problematic for soil variables such as pH, moisture or nutrients, which can change dramatically within a few metres.

Here, the approximation of site conditions by mean ecological indicator values can improve the predictive power substantially (Scherrer and Guisan 2019). Likewise, in broad-scale vegetation classification studies, mean EIVE values per plot would allow a better characterisation of the distinguished vegetation units. Lastly, one should not forget that most countries in Europe do not have a national EIV system, and here EIVE could fill the gap.

Violin plots showing largely continuous value distributions of the niche position and niche width values of the five indicators in EIVE 1.0 (image from the original article).

Almost on the same day as EIVE 1.0 another supranational system of ecological indicator values in Europe has been published by Tichý et al. (2023) with a similar approach.

Thus, it will be important for vegetation scientists in Europe to understand the pros and cons of both systems to allow the wise selection of the most appropriate tool:

  • EIVE 1.0 is based on 31 regional EIV systems, while Tichý et al. (2023) uses 12.
  • Both systems provide indicator values for moisture, nitrogen/nutrients, reaction, light and temperature, while Tichý et al. (2023) additionally has a salinity indicator.
  • Tichý et al. (2023) aimed at using the same scales as Ellenberg et al. (1991), which means that the scales vary between indicators (1–9, 0–9, 1–12), while EIVE has a uniform interval scale of 0–10 for all indicators.
  • Only EIVE provides niche width in addition to niche position. Niche width is an important aspect of the niche and might be used to improve the calculation of mean indicator values per plot (e.g. by weighting with inverse niche width).
  • The taxonomic coverage is larger in EIVE than in Tichý et al. (2023): 14,835 vs. 8,908 accepted taxa and 11,148 vs. 8,679 species.
  • EIVE provides indicator values for accepted subspecies, while Tichý et al. (2023) is restricted to species and aggregates. Separate indicator values for subspecies might be important for two reasons: (a) subspecies often strongly differ in at least one niche dimension; (b) many of the taxa now considered as subspecies have been treated at species level in the regional EIV systems.
  • Tichý et al. (2023) added 431 species not contained in any of the source systems based on vegetation-plot data from the European Vegetation Archive (EVA; Chytrý et al. 2016) while EIVE calculated the European indicator values only for taxa occurring at least in one source system. 
  • While both systems present maps that suggest a good coverage across Europe, Tichý et al. (2023)’s source systems largely were from Central Europe, NW Europe and Italy, but, unlike EIVE, these authors did not use source systems from the more “distal” parts of Europe, such as Sweden, Faroe Islands, Russia, Georgia, Romania, Poland and Spain, and they used only a small subset of indicators of the EIV systems of Ukraine, Greece and the Alps.
  • In a validation with GBIF-derived data on temperature niches, Dengler et al. (2023) showed that EIVE has a slightly stronger correlation than Tichý et al. (2023)’s indicators (r = 0.886 vs. 0.852).
The correlation of EIVE-T values of species with GBIF-derived temperature niche data was high and even higher when restricting the calculation to those species whose consensus value was based on at least four sources (image from the original article).

How did EIVE manage to integrate all EIV systems in Europe that contained at least one of the selected indicators for vascular plants, while Tichý et al. (2023) used only a small subset?

This difference is mainly due to a more complex workflow in EIVE (which also was one of the reasons why the preparation took so long). First, Tichý et al. (2023) restricted their search to EIV systems and indicators that had the same number of categories as the “original” Ellenberg system.

Second, from these they discarded those that showed a too low correlation with Ellenberg. By contrast, EIVE’s workflow allowed the use of any system with an ordinal (or even metric) scale, irrespective of the number of categories or the initial match with Ellenberg et al. (1991).

EIVE also did not treat one system (Ellenberg) as the master to assess all others but considered each of them equally valid. While indeed the individual EIV systems are often quite inconsistent, i.e. even if they refer to Ellenberg, the same value of an indicator in one system might mean something different in another system, our iterative linear optimisation enabled us to adjust all 31 systems for the five indicators to a common basis.

This in turn allowed deriving EIVE as the consensus system of all the source systems. The fact that in our validation of the temperature indicator, EIVE performed better than Tichý et al. (2023) and much better than most of the regional EIV systems might be attributable to the so-called wisdom of the crowd, going back to the statistician Francis Galton who found that averaging numerous independent assessments (even by laymen) of a continuous quantity can leads to very good estimates of the true value. 

Apart from the indicator values themselves, EIVE has a second main feature that might not be so obvious at first glance, but which actually took the EIVE team, including several taxonomists, more time than the workflow to generate the indicator values themselves: the taxonomic backbone. EIVE for vascular plants is fully based on the taxonomic concept (including the synonymic relationships) of the Euro+Med Plantbase.

However, since Euro+Med lacks an important part of taxa that are frequently recorded in vegetation plots, to make our backbone fully usable to vegetation science, we expanded it beyond Euro+Med to something called “Euro+Med augmented”. We particularly added hybrids, neophytes and aggregates, three groups of plants hitherto only very marginally covered in Euro+Med. All additions were done by experts consistently with the taxonomic concept of Euro+Med and are fully documented. Likewise, many additional synonym relationships had to be added that were missing in Euro+Med.

Finally, we implemented the so-called “concept synonymy” (see Jansen and Dengler 2010), which allows the assignment of the same name from different sources to different accepted names (“taxonomic concepts”). This applies mainly to nested taxa that are treated at different levels in different sources, e.g. once as species with several subspecies, once as aggregate with several species. However, there are also some cases of misapplied names (i.e. names that were not used in agreement with their nomenclatural type in certain EIV systems). Such cases generally cannot be solved by the various tools for automatic taxonomic cleaning, but require experts who make a case-by-case decision.

The whole taxonomic workflow of EIVE is fully transparent with an R code that “digests”:

(a) the names as they are in the source systems,

(b) the official Euro+Med database and

(c) tables that document our additions and modifications (with reasons and references).

This comprehensive documentation will allow continuous and efficient improvement in the future, be it because of taxonomic novelties adopted in Euro+Med or because EIVE’s experts decide to change certain interpretations. That way, “Euro+Med augmented” and the accompanying R-based workflow can also be a valuable tool for other projects that wish to harmonise plant taxonomic information from various sources at a continental scale, e.g. in vegetation-plot databases such as GrassPlot (Dengler et al. 2018) and EVA (Chytrý et al. 2016).

The publication of EIVE 1.0 is not the endpoint, but rather a starting point for future developments in a community-based approach.

Together with interested colleagues from outside, the EIVE core team plans to prepare better and more comprehensive releases of EIVE in the future, including updates to its taxonomic backbone.

Future releases of EIVE will be published in fixed versions, typically together with a paper that describes the changes in the content.

As steps for the next two years, we anticipate that we will first add further taxa (bryophytes, lichens, macroalgae) and some additional indicators, both of which are relatively easy with our established R-based workflow. Then we plan EIVE 2.0 that will use the approx. 2 million vegetation plots in EVA (Chytrý et al. 2016) to re-calibrate EIVE for all taxa (see

We invite you to get into contact with us if you have:

(a) a new or overlooked indicator value system for any taxonomic group in Europe and adjacent areas (including comprehensive datasets of measured environmental data in vegetation plots);

(b) suggestions for improvements of our taxonomic backbone;

(c) a paper idea in the EIVE context that you would like to realise together with the EIVE core team (since everything is OA, you can, of course, use EIVE 1.0 for any possible purpose without notifying us as long as you cite EIVE properly).

Last but not least, any test of the validity and performance of EIVE, alone or in comparison with Tichý et al. (2023), with in situ measured environmental variables, locally or even continentally, would be most welcome.


This Behind the paper post refers to the article Ecological Indicator Values for Europe (EIVE) 1.0 by Jürgen Dengler, Florian Jansen, Olha Chusova, Elisabeth Hüllbusch, Michael P. Nobis, Koenraad Van Meerbeek, Irena Axmanová, Hans Henrik Bruun, Milan Chytrý, Riccardo Guarino, Gerhard Karrer, Karlien Moeys, Thomas Raus, Manuel J. Steinbauer, Lubomir Tichý, Torbjörn Tyler, Ketevan Batsatsashvili, Claudia Bita-Nicolae, Yakiv Didukh, Martin Diekmann, Thorsten Englisch, Eduardo Fernandez Pascual, Dieter Frank, Ulrich Graf, Michal Hájek, Sven D. Jelaska, Borja Jiménez-Alfaro, Philippe Julve, George Nakhutsrishvili, Wim A. Ozinga, Eszter-Karolina Ruprecht, Urban Šilc, Jean-Paul Theurillat, and François Gillet published in Vegetation Classification and Survey (


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Brief personal summaries: 

Jürgen Dengler is a Professor of Vegetation Ecology at the Zurich University of Applied Science (ZHAW) in Wädenswil, Switzerland. Among others, he cofounded the European Vegetation Database (EVA), the global vegetation-plot database “sPlot” and the “GrassPlot” database of the Eurasian Dry Grassland Group. His major research interests are grassland ecology, grassland conservation, biodiversity patterns, macroecology, vegetation change, broad-scale vegetation classification, methodological developments in vegetation ecology and ecoinformatics.

Florian Jansen is a Professor of Landscape Ecology at the University of Rostock, Germany. His research interests are vegetation ecology and dynamics, mire ecology including greenhouse gas emissions, and numerical ecology with R. He (co-)founded the German Vegetation Database, the European Vegetation Database (EVA), and the global vegetation-plot database “sPlot”. He wrote the R package eHOF for modelling species response curves along one-dimensional ecological gradients.

François Gillet is an Emeritus Professor of Community Ecology at the University of Franche-Comté in Besançon, France. His major research interests are vegetation diversity, ecology and dynamics, grassland and forest ecology, integrated synusial phytosociology, numerical ecology with R, dynamic modelling of social-ecological systems.



Chytrý, M., Hennekens, S.M., Jiménez-Alfaro, B., Knollová, I., Dengler, J., Jansen, F., Landucci, F., Schaminée, J.H.J., Aćić, S., (…) & Yamalov, S. 2016. European Vegetation Archive (EVA): an integrated database of European vegetation plots. Applied Vegetation Science 19: 173–180.

Dengler J, Wagner V, Dembicz I, García-Mijangos I, Naqinezhad A, Boch S, Chiarucci A, Conradi T, Filibeck G, … Biurrun I (2018) GrassPlot – a database of multi-scale plant diversity in Palaearctic grasslands. Phytocoenologia 48: 331–347.

Dengler, J., Jansen, F., Chusova, O., Hüllbusch, E., Nobis, M.P., Van Meerbeek, K., Axmanová, I., Bruun, H.H., Chytrý, M., (…) & Gillet, F. 2023. Ecological Indicator Values for Europe (EIVE) 1.0. Vegetation Classification and Survey 4: 7–29.

Ellenberg H, Weber HE, Düll R, Wirth V, Werner W, Paulißen D (1991) Zeigerwerte von Pflanzen in Mitteleuropa. Scripta Geobotanica 18: 1–248.

Jansen F, Dengler J (2010) Plant names in vegetation databases – a neglected source of bias. Journal of Vegetation Science 21: 1179–1186.

Midolo, G., Herben, T., Axmanová, I., Marcenò, C., Pätsch, R., Bruelheide, H., Karger, D.N., Acic, S., Bergamini, A., Bergmeier, E., Biurrun, I., Bonari, G., Carni, A., Chiarucci. A., De Sanctis, M., Demina, O., (…), Dengler, J., (…) & Chytrý, M. 2023. Disturbance indicator values for European plants. Global Ecology and Biogeography 32: 24–34.

Scherrer D, Guisan A (2019) Ecological indicator values reveal missing predictors of species distributions. Scientific Reports 9: Article 3061.

Tichý, L, Axmanová, I., Dengler, J., Guarino, R., Jansen, F., Midolo, G., Nobis, M.P., Van Meerbeek, K., Aćić, S., (…) & Chytrý, M. 2023. Ellenberg-type indicator values for European vascular plant species. Journal of Vegetation Science 34: e13168.

A double defensive mutualism? A case between plants, extrafloral nectaries, and trophobionts

Тhis is the first case reported in the literature of a double defensive mutualism occurring simultaneously on a single plant species.

Guest blog post by Cássio Pereira

The Zeyheria montana shrub is quite common in the Brazilian Cerrado and is known to have extrafloral nectaries on the leaf blade that attract patrolling ants such as the aggressive Ectatomma tuberculatum. The ant, in turn, defends the leaves against the action of herbivores. However, extrafloral nectaries can distract ants on the leaves, segregating them from the reproductive parts and preventing them from driving away pollinators, which can benefit the action of florivores and nectar robbers.

Surprisingly, in southeastern Brazil, we observed a second defensive mutualism occurring on the reproductive tissues of these shrubs between E. tuberculatum and the treehopper Guayaquila xiphias, which provides the ant with honeydew in exchange for protection. This trophobiosis relationship (interaction between ants and phytophagous hemipterans that secrete sugary exudates) seems to be effective not only in the defense of floral buds and flowers, but also of the fruit, which, despite being dry, contains a lot of water in its formation and is attacked by beetles of the Curculionidae family.

The treehoppers G. xiphias at the base of Z. montana fruits.

As far as we know, this is the first case reported in the literature of a double defensive mutualism occurring simultaneously on a single plant species. Given this record, important questions arise regarding these interactions. Is the trophobiosis that occurs in reproductive organs capable of increasing the fitness of these plants? Although these ants are probably also scaring away possible pollinating insects, could the fact that Z. montana is primarily pollinated by hummingbirds offset this loss given that hummingbirds are larger and perhaps immune to ant attacks?

Our record raises more questions than it answers. Long-term Z. montana population studies would help improve our ecological understanding of these interactions.

Leaves and Spines: A new spiny-tailed leaf-toed gecko from the unexplored coastal savanna of Angola

A random survey in a poorly explored region of the southern Benguela Province of Angola, led to the discovery of a unique new spiny-tailed leaf-toed gecko.

Guest blog post by Javier Lobon-Rovira

After the long, hard days of fieldwork in the arid coastal region of southern Angola, Angolan researcher Pedro Vaz Pinto and his enthusiastic son Afonso, found the best spot to spend the night before heading back home. In the area of Carivo, every night was different: after four visits to this unique place, a different gecko species always showed up to add to the growing species list.

On a random night in August 2021, they went for a routine night walks and came across this unique gecko. In shock, Pedro immediately started sharing photos with the coauthors, Werner and Javier. “Guys, I think I found a new Kolekanos” he said.

Kolekanos is a unique and iconic gecko genus in Africa and more specifically only known from southwestern Angola. Kolekanos plumicaudus was described by one of the most recognized herpetologists in Africa, the late Wulf Haacke (1936– 2021).

Feather-tailed Kolekanos was at that point a monotypic genus (only one species in the genus), known only from ~200km south of the new discovery. Immediately, we all knew that what we were looking in that photo was something different from the known K. plumicaudus. “It is a Kolekanos… but, those are spines in the tail, not feathers…” was one of the most common reactions that night. So, we started planning our next trip to the area.

Three months later we were back at Carivo, now focusing on finding more specimens of that unique gecko. After only one hour, we spotted at least six specimens among the semi-dessert vegetations and rocks. At that moment, all doubt went away. The behavior and habitat of the new gecko was completely distinctive in comparison with K. plumicaudus.

Then, with our goal achieved and based on the big success of the first night, we planned to go back through different areas to explore some of the most remote regions in Northern Namibe and southern Benguela provinces. After two days driving on impossible roads, the team reached Ekongo. That night we were tired, so we decided to have a short walk around the camp. And… there it was…! Like a ghost, this small, cryptic, and elusive gecko started  showing up in every big rock boulder. 

This study, now published in the journal ZooKeys, also highlights how poorly explored and understood some regions of Angola remain, even as it has been considered as an important source of diversification and endemism in West Africa.

‘Who is in your database and why does it matter?’

The uncertainty about a person’s identity hampers research, hinders the discovery of expertise, and obstructs the ability to give attribution or credit for work performed. 

Collection discovery through disambiguation

Guest blog post by Sabine von Mering, Heather Rogers, Siobhan Leachman, David P. ShorthouseDeborah Paul & Quentin Groom

Worldwide, natural history institutions house billions of physical objects in their collections, they create and maintain data about these items, and they share their data with aggregators such as the Global Biodiversity Information Facility (GBIF), the Integrated Digitized Biocollections (iDigBio), the Atlas of Living Australia (ALA), Genbank and the European Nucleotide Archive (ENA). 

Even though these data often include the names of the people who collected or identified each object, such statements may be ambiguous, as the names frequently lack any globally unique, machine-readable concept of their shared identity.

Despite the data being available online, barriers exist to effectively use the information about who collects or provides the expertise to identify the collection objects. People have similar names, change their name over the course of their lifetime (e.g. through marriage), or there may be variability introduced through the label transcription process itself (e.g. local look-up lists). 

As a result, researchers and collections staff often spend a lot of time deducing who is the person or people behind unknown collector strings while collating or tidying natural history data. The uncertainty about a person’s identity hampers research, hinders the discovery of expertise, and obstructs the ability to give attribution or credit for work performed. 

Disambiguation activities: the act of churning strings into verifiable things using all available evidence – need not be done in isolation. In addition to presenting a workflow on how to disambiguate people in collections, we also make the case that working in collaboration with colleagues and the general public presents new opportunities and introduces new efficiencies. There is tacit knowledge everywhere.

More often than not, data about people involved in biodiversity research are scattered across different digital platforms. However, with linking information sources to each other by using person identifiers, we can better trace the connections in these networks, so that we can weave a more interoperable narrative about every actor.

That said, inconsistent naming conventions or lack of adequate accreditation often frustrate the realization of this vision. This sliver of natural history could be churned to gold with modest improvements in long-term funding for human resources, adjustments to digital infrastructure, space for the physical objects themselves alongside their associated documents, and sufficient training on how to disambiguate people’s names.

“He aha te mea nui o te ao. He tāngata, he tāngata, he tāngata.

“What is the most important thing in the world? It is people, it is people, it is people.”

(Māori proverb)

The process of properly disambiguating those who have contributed to natural history collections takes time. 

The disambiguation process involves the extra challenge of trying to deduce “who is who” for legacy data, compared to undertaking this activity for people alive today. Retrospective disambiguation can require considerable detective work, especially for scarcely known people or if the community has a different naming convention. Provided the results of this effort are well-communicated and openly shared, mercifully, it need only be done once.

At the core of our research is the question of how to solve the issue of assigning proper credit

In our recent Methods paper, we discuss several methods for this, as well as available routes for making records available online that include not only the names of people expressed as text, but additionally twinned with their unique, resolvable identifiers. 

Disambiguation is a cycle. Enrichment of the data feeds off itself leading to further disambiguation. As more names are disambiguated and more biographical data are accumulated, it becomes easier to disambiguate more names. 

First and foremost, we should maintain our own public biographical data by making full use of ORCID. In addition to preserving our own scientific legacy and that of the institutions that employ us, we have a responsibility to avoid generating unnecessary disambiguation work for others. 

For legacy data, where the people connected to the collections are deceased, Wikidata can be used to openly document rich bibliographic and demographic data, each statement with one or more verifiable references. Wikidata can also act as a bridge to link other sources of authority such as VIAF or ORCID identifiers. It has many tools and services to bulk import, export, and to query information, making it well-suited as a universal democratiser of information about people often walled-off in collection management systems (CMS). 

A network of the top twenty most used identifiers for biologists on Wikidata.

Once unique identifiers for people are integrated in collection management systems, these may be shared with the global collections and research community using the new Darwin Core terms, recordedByID or identifiedByID along with the well-known, yet text-based terms, recordedBy or identifiedBy. 

Approximately 120 datasets published through GBIF now make use of these identifier-based terms, which are additionally resolved in Bionomia every few weeks alongside co-curated attributions newly made there. This roundtrip of data – emerging as ambiguous strings of text from the source, affixed with resolvable identifiers elsewhere, absorbed into the source as new digital annotations, and then re-emerging with these fresh, identifier-based enhancements – is an exciting approach to co-manage collections data.

Round tripping. In Bionomia, people identifiers from Wikidata and ORCID are used to enrich data published via GBIF, thus linking natural history specimens to the world’s collectors.

Disambiguation work is particularly important in recognising contributors who have been historically marginalized. For example, gender bias in specimen data can be seen in the case of Wilmatte Porter Cockerell, a prolific collector of botanical, entomological and fossil specimens. Cockerell’s collections are often attributed to her husband as he was also a prolific collector and the two frequently collected together. 

On some labels, her identity is further obscured as she is simply recorded as “& wife” (see example on GBIF). Since Wilmatte Cockerell was her husband’s second wife, it can take some effort to confirm if a specimen can be attributed to her and not her husband’s first wife, who was also involved in collecting specimens. By ensuring that Cockerell is disambiguated and her contributions are appropriately attributed, the impact of her work becomes more visible enabling her work to be properly and fairly credited.

Thus, disambiguation work helps to not only give credit where credit is due, thereby making data about people and their biodiversity collections more findable, but it also creates an inclusive and representative narrative of the landscape of people involved with scientific knowledge creation, identification, and preservation. 

A future – once thought to be a dream – where the complete scientific output of a person is connected as Linked Open Data (LOD) is now

Both the tools and infrastructure are at our disposal and the demand is palpable. All institutions can contribute to this movement by sharing data that include unique identifiers for the people in their collections. We recommend that institutions develop a strategy, perhaps starting with employees and curatorial staff, people of local significance, or those who have been marginalized, and to additionally capitalize on existing disambiguation activities elsewhere. This will have local utility and will make a significant, long-term impact. 

The more we participate in these activities, the greater chance we will uncover positive feedback loops, which will act to lighten the workload for all involved, including our future selves!

The disambiguation of people in collections is an ongoing process, but it becomes easier with practice. We also encourage collections staff to consider modifying their existing workflows and policies to include identifiers for people at the outset, when new data are generated or when new specimens are acquired. 

There is more work required at the global level to define, update, and ratify standards and best practices to help accelerate data exchange or roundtrips of this information; there is room for all contributions. Thankfully, there is a diverse, welcoming, energetic, and international community involved in these activities. 

We see a bright future for you, our collections, and our research products – well within reach – when the identities of people play a pivotal role in the construction of a knowledge graph of life.

You would like to participate and need support getting disambiguation of your collection started? Please contact our TDWG People in Biodiversity Data Task Group.

A good start is also to check Bionomia to find out what metrics exist now for your institution or collection and affiliated people.

The next steps for collections: 7 objectives that can help to disambiguate your institutions’ collection:

1. Promote the use of person identifiers in local, national or international outreach, publishing and research activities

2. Increase the number of collection management systems that use person identifiers

3. Increase the number of living collectors registered and using an ORCID identifier when contributing to collections

4. Undertake disambiguation in the national languages of many countries

5. Increase the number of identified people on Wikidata linked to collections

6. Increase the number of people in collections with expertise in person disambiguation

7. Collaborate towards an exchange standard for attribution data

A real example of how a name string is disambiguated and the steps taken in documenting it. Wikidata item of Jean-André Soulié


Methods publication:

Groom Q, Bräuchler C, Cubey RWN, Dillen M, Huybrechts P, Kearney N, Klazenga N, Leachman S, Paul DL, Rogers H, Santos J, Shorthouse DP, Vaughan A, von Mering S, Haston EM (2022) The disambiguation of people names in biological collections. Biodiversity Data Journal 10: e86089.


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Invasive species denialism: what is it, and what can we do about it?

Even when there is agreement on the impacts of invasive species on ecosystems, some stakeholders nevertheless deny the need for, or benefit of managing invasive species.

Guest blog post by Noelle G. Stratton, Nicholas E. Mandrak, and Nicole Klenk

Invasive species denialism (ISD) is a hot topic in recent invasion ecology discourse. Many of us are familiar with the concept of science denialism, particularly during recent discussions about climate change and the ongoing COVID-19 pandemic. Essentially, a person who exhibits science denialism is skeptical of, or refuses to believe, the scientific facts about a topic. Much of the discussion about ISD has focused on characterising it as a form of science denialism. However, while science denialism may be one form of ISD, it is not the only one.

Understanding the different forms of ISD is an important step in learning more about what drives ISD positions, and how those positions can be overcome to improve invasive species management. Recently, researchers at the University of Toronto outlined these ISD forms in a new paper in NeoBiota. While these framings are not the only ways to characterize invasive species denialism, they demonstrate that there are multiple framings to the ways that people deny the imperative to manage all invasive species as prescribed by early detection and rapid response.

So, what are the forms of ISD?

Venn diagram of the three forms of invasive species based on interviews and focus groups with invasive species community members in the Great Lakes region, including interested publics and decision-makers: 1) Invasive species denialism; 2) invasive species cynicism; and 3) invasive species nihilism. Each has different motivations and ways of talking about invasive species. Notably, all forms include an opposition to invasive species engagement or management efforts.

Invasive species denialism is the form that will typically come to mind when you picture a “science denialist”. Someone who does not believe in invasive species, or says that the existing scientific literature is all wrong, would fall within this framing. However, it is more complex than that. Invasive species practitioners also identified some of those who believed in invasive species and supported their management under this framing.

For example, folks who wanted management to happen immediately, be 100% effective, or have no risks to them or the environment whatsoever, were considered another form of denialist. This is because while these people supported invasive species management, they were still opposed to certain management efforts due to a lack of understanding of the science behind that management. Similarly, people who agree invasive species are a problem but say “this isn’t my problem, and I shouldn’t have to do anything about it” when shown evidence otherwise were also framed as denialists, as it again indicated a denial, or at least a lack of understanding of the scientific facts.

Invasive species cynicism is the form where someone may well understand what invasive species are and the science behind their management. However, they may still oppose management because they believe it will harm them in some way.

For example, someone who does not want to have to check and clean their boat to prevent an invasive species spread because it takes too much time would be categorized as an invasive species cynic. As well, someone who does not want to cooperate with management efforts because they personally like a particular invasive species and would like it to persist, despite knowing its potential for harms to the ecosystem or economy, is also an invasive species cynic. From these examples, it should be clear that this form of ISD is quite different from what we would think of as a “science denialist”. They understand the science, but it just does not motivate their beliefs or behaviour on this topic.

This research was also recently presented at the International Conference on Aquatic Invasive Species by co-author Noelle G. Stratton. Invasive species nihilism, in particular, prompted discussion both in-person and on social media.

Invasive species nihilism is the form that does not appear to take into account the science behind invasive species or their management at all. Rather, it revolves around the idea that invasive species research, management, or engagement are essentially a waste of time. The efforts were pointless and the results useless. This framing also differed from the other two forms in that the folks who expressed these beliefs often directly approached invasive species practitioners during the course of their work to inform them that their job was meaningless and to ask them why they bothered. This type of framing has the greatest potential to impact invasive species researchers and practitioners personally, and it is potentially the most difficult form of denialism to surmount during engagement and management efforts.

How can invasive species denialism impact management efforts?

ISD has the potential to hinder management efforts in a few different ways. Invasive species denialists may slow down decision-making by stalling or halting discussions with other stakeholders. In some cases, invasive species cynics have taken direct action to interfere with the implementation of policies that would aid with management efforts. Invasive species nihilism could make some stakeholders less likely to engage with managers because they have come to believe that management is pointless, and managers themselves may endure the stress of hearing that their work is not of value to people with this perspective. The effects that ISD may have on management are varied and depend largely on the type of framing of ISD being used. Similarly, the way that we respond to someone that we believe to be an invasive species denialist should be informed by the framing of ISD they are using.

“An understanding of these framings is also vital to respond to instances of ISD appropriately. Whether we are being confronted with anti-science contrarianism, environmental cynicism, or outbursts of nihilism, should inform our responses and our strategies to counter these positions.” (Stratton et al. 2022)

The framings of ISD explored in this research suggest that a diversity of interpretations of species movements, and value judgments about their impacts and the need for management, exist. This has the potential to problematize reductionist claims that all critiques of invasive species management are simply a denial of scientific facts. These results provide evidence that even when there is agreement on the impacts of invasive species on ecosystems, some stakeholders nevertheless deny the need for, or benefit of managing invasive species. This study further contributes to ongoing scholarly and practitioner conversations about the normative assumptions of invasive species biology and their implications for invasive species management and governance.

Research article:

Stratton NG, Mandrak NE, Klenk N (2022) From anti-science to environmental nihilism: the Fata Morgana of invasive species denialism. NeoBiota 75: 39-56.

Image credits: diagram by NG Stratton; comic panels by NG Stratton, via material from Flickr (ChrisA1995, CC BY 2.0; Mike, CC BY-NC-SA 2.0; the-difference CC BY-NC-SA 2.0) and Studio Alternativi (Esetefania Quevedo).

Can amateurs combat the threat of alien species? Tracking introduced species in the world of citizen science

How citizen scientists documented the spread of an alien mantis across Australia

Guest blog post by Matthew Connors

From the infamous cane toad to the notorious spotted lanternfly, we all know the drastic effects that introduced species can have on both ecosystems and agriculture.

In today’s interconnected world, these alien species are being moved around the globe more frequently than ever before.  Hitchhikers and stowaways on ships, planes, and other vehicles can cause irreversible and catastrophic damage to fragile native ecosystems and to us humans, and tens of billions of dollars are spent every year trying to control these invaders.

Spotted lanternfly. Photo by peterlcoffey licensed under CC BY-NC-SA 2.0.

But one of the greatest problems for researchers and government bodies trying to combat these threats is that it can be incredibly difficult to monitor the invaders even when we know they’re here.

So how on earth is anyone supposed to detect when a new species has invaded?  Many of these organisms are small, inconspicuous, and difficult to identify, and by the time they’ve been spotted it’s often already too late to act.

What if there was a way to quickly and easily find invasive organisms all over the world?  Enter the world of Citizen Science, where anybody and everybody can produce important scientific data without even leaving their backyard.  Just by taking a photograph of an organism and uploading it to a citizen science platform like iNaturalist or QuestaGame, amateurs and enthusiasts can provide scientists with invaluable records from across the globe.

A screenshot from the iNaturalist homepage, captured on July 7, 2022.

Back in 2015, when amateur naturalist Adam Edmonds spotted an unusual praying mantis in his garden, he took a photo and posted it to the Australian citizen science platform BowerBird.  When even the local experts didn’t recognise it, a specimen was sent off to mantis specialist Graham Milledge.  He confirmed that it was a newly introduced species – the South African Mantis (Miomantis caffra).

Miomantis caffra, an adult female from Victoria, Australia. Photo by Adam Edmonds

Since then, this alien mantis has spread across Australia from Sydney to Perth.  And every step of the way, citizen scientists have been there to document its spread.

Last month, all of these citizen science records were compiled by entomologist Matthew Connors of James Cook University (Queensland, Australia) into the first comprehensive report of the mantis’s presence in Australia.  Understanding where the species has spread and what impacts it has had on native species is crucial to managing and controlling it.

The introduced South African Mantis (Miomantis caffra) preys on a native Harlequin Bug (Dindymus versicolor) in Geelong, Australia.  Photo by Kelly Clitheroe

The research found that the South African Mantis has spread through suburban habitats in three Australian states (Victoria, New South Wales, and Western Australia) and one offshore territory (Norfolk Island).  It probably arrived in these regions as egg cases attached to plants and equipment, and it can now be found in high numbers, especially during late summer and early autumn.  Despite this, it appears to be highly localised and has only been recorded in suburbia, and furthermore there has not been any noticeable impact on native species.

Miomantis caffra, egg case (ootheca) from Victoria, Australia. Photo by Ken Walker

None of this research would have been possible without citizen scientists – the dedicated community of enthusiasts and amateurs who share their finds with researchers online.  Photographs from citizen science platforms and social media sites have been instrumental in showing just how far the South African Mantis has spread.  In fact, more than 90% of the records of the species come from citizen scientists, and without them we would barely know anything.

These days, more and more researchers are realising just how useful citizen science can be.  As well as tracking introduced species, citizen scientists have rediscovered rare creatures, documented never-before-seen behaviours, and even discovered completely new species.

Miomantis caffra, an adult female from Victoria, Australia. Photo by Matthew Connors

This latest research, published in the Journal of Orthoptera Research, is among a handful of recent studies that have gone a step further though – instead of just being a source of data, the citizen scientists were invited to take part in the entire research process, from data collection all the way through to publishing.  After all, they did all of the fieldwork!

Research like this is proof that anyone can be a citizen scientist in today’s day and age – so what are you waiting for?

Research article: Connors MG, Chen H, Li H, Edmonds A, Smith KA, Gell C, Clitheroe K, Miller IM, Walker KL, Nunn JS, Nguyen L, Quinane LN, Andreoli CM, Galea JA, Quan B, Sandiford K, Wallis B, Anderson ML, Canziani EV, Craven J, Hakim RRC, Lowther R, Maneylaws C, Menz BA, Newman J, Perkins HD, Smith AR, Webber VH, Wishart D (2022) Citizen scientists track a charismatic carnivore: Mapping the spread and impact of the South African Mantis (Miomantidae, Miomantis caffra) in Australia. Journal of Orthoptera Research 31(1): 69-82.

Novel research seeks to solve environmental challenges in BioRisk’s latest issue

The special issue features 35 studies presented at the International Seminar of Ecology 2021

Guest blog post by Prof. Stephka Chankova, PhD

The new special issue of BioRisk compiles materials presented at the International Seminar of Ecology – 2021. The multidisciplinary nature of modern ecology was demonstrated by the main topics of the Seminar: biodiversity and conservation biology, biotic and abiotic impact on the living nature, ecological risk and bioremediation, ecosystem research and services, landscape ecology, and ecological agriculture.

Research teams from various universities, institutes, organizations, and departments, both from Bulgaria and abroad, took part in the Seminar. Foreign participants included: Environmental Toxicology Research Unit (Egypt), Pesticide Chemistry Department, National Research Centre (Giza, Egypt); National Institute for Agrarian and Veterinary Research (Oeiras, Portugal), Centre for Ecology, Evolution and Environmental Changes (Lisbon, Portugal); Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences (Moscow, Russia).

Biorisk’s latest issue: Current trends of ecology

Some of the reports presented joint research of Bulgarian scientists and scientists from Germany, the Czech Republic, Lithuania, Romania, Slovenia, Spain, and the USA. After assessment by independent reviewers, the articles published in the journal cover the topics presented and discussed at the Seminar. 

A set of reports were focused on the anthropogenic and environmental impacts on the biota. Soil properties were shown as a factor that can modulate the effect of heavy metals, present in chronically contaminated soils. Different ap­proaches to overcome environmental pollution were presented and discussed: zeolites as detoxifying tools, microalgae for the treatment of contaminated water bodies, and a newly developed bio-fertilizer, based on activated sludge combined with a bacte­rial strain with detoxifying and plant growth-promoting properties. The clear need for the enlargement of existing monitoring program by including more bioindicators and markers was pointed out.

It was shown that, by using various markers for the evaluation of environmentally induced stress response at different levels (microbiological, molecular, biochemical), it is possible to gain insights of the organisms’ protection and the mechanisms involved in resistance formation. The contribution of increased DNA repair capacity and AOS to the development of environmental tolerance or adaptation was also shown.

Important results for understanding the processes of photoprotection in either cyanobacteria or algae, and higher plants were obtained by in vitro reconstitution of complexes of stress HliA protein with pigments. The crucial role of the cellular physiological state, as a critical factor in determining the resistance to environmental stress with Q cells was demonstrated.

Several papers were focused on the action of bioactive substances of plants origin. The bioactivity was shown to depend strongly on chemical composition. Origanum vulgare hirtum essential oil was promoted as a promising candidate for the purposes of “green” technologies. Analyzing secondary metabolites of plants, it was shown that their productivity in vitro is a dynamic process closely related to the plant growth and development, and is in close relation with the interactions of the plant with the environment.

Origanum vulgare hirtum. Photo by cultivar413 under a CC-BY 2.0 license

The influence of the agricultural system type on essential oil production and antioxidant activity of industrially-cultivated Rosa damascena in the Rose valley (Bulgaria) was reported, comparing organic vs conventional farming. The rose extracts from organic farming were shown to accumulate more phenolic compounds, corresponding to the higher antioxidant potential of organic roses.

A comparative study, based on official data from the statistics office of the EU and the Member countries, concerning viral infection levels in intensive and organic poultry farming, demonstrated that free-range production had a higher incidence of viral diseases with a high zoonotical potential.

Pollinators of Lavandula angustifolia, as an important factor for optimal production of lavender essential oil, were analyzed. It was concluded that, although lavender growers tend to place beehives in the fields for optimal essential oil production, it was crucial to preserve wild pollinators, as well.

Lavandula angustifolia inflorescence excluded from pollinators.

New data reported that essential oils and alkaloid-rich plant extracts had the strongest acetylcholinesterase inhibitory activity and could be proposed for further testing for insect control.

It was reported that the vegetation diversity of Bulgaria had still not been fully investigated. Grasslands, broad-leaved forests, and wetlands are the best investigated habitats, while data concerning ruderal, shrubland, fringe, and chasmophytic vegetation in Bulgaria are scarce.

Other important topics were reported and discussed in this session: the possibility of pest control using pteromalids as natural enemies of pests in various crops; the main reasons responsible for the population decrease of bumblebees – habitat destruction, loss of floral resources, emerging diseases, and increased use of pesticides (particularly neonicotinoids); the strong impact of temperature and wind on the distribution of zooplankton complexes in Mandra Reservoir, in Southeastern Bulgaria; an alternative approach for the ex-situ conservation of Stachys thracica based on in vitro shoot culture and its subsequent adaptation under ex vitro conditions.

Bombus hortorum/subterraneus collecting nectar in 1991, and B B. wurflenii/lapidarius worker robbing nectar of Gentiana asclepiadea in 2017

New information was presented concerning pre-monitoring geochemical research of river sediments in the area of Ada Tepe gold mining site (Eastern Rhodopes). The obtained results illustrate that the explored landscapes have been influenced by natural geochemical anomalies, as well as, impacted by human activity. The forests habitat diversity of Breznik Municipality was revealed, following the EUNIS Classification and initial data from the Ministry of Environment and Water and the Forestry Management Plans. It was shown that, in addition to the dominant species Quercus dalechampii, Quercus frainetto, Fagus sylvatica, Carpinus betulus, some artificial plantations with Pinus nigra and Pinus sylvestris were also present, as well as non-native species, such as Robinia pseudoacacia and Quercus rubra.

Models for Predicting Solution Properties and Solid-Liquid Equilibrium in Cesium Binary and Mixed Systems were created. The results are of great importance for the development of strategies and programs for nuclear waste geochemical storage. In conclusion, many results in different areas of ecology were presented in the Seminar, followed by interesting discussions. A lot of questions were answered, however many others remained open. A good platform for further discussion will be the next International Seminar of Ecology – 2022, entitled Actual Problems of Ecology.