Featured

Introducing: Journal News

The research being conducted and the media for sharing findings change through time. In the past decade, these changes have been particularly rapid, as the technology available for measuring the world and for publishing papers have each gone through multiple step changes. The journal is adapting to these changes in service of our research community. This Journal News section of the blog is intended to communicate these adaptations to maintain a leading quality outlet for your work.

All changes at the Journal of Biogeography will reflect our commitment to continually (1) keep pace with and lead advances in the discipline, (2) deliver a constructive, productive process for publishing your biogeographical studies, (3) enhance value to the community, such as replication and reuse of your work, and (4) add value to you by widely disseminating your research to a global audience.

To attain these goals, we made several changes at the journal since September 2019:
Cover Image: published for free to highlight research in each issue
Editors’ Choice: will be ‘full access’ for two years at no cost to the author
– Social media: new team to increase visibility and achieve broader reach
– Updated our statement of the journal’s scope

Other improvements are in the works. Watch for announcements in the coming months.

Featured

Introducing: Featured Researchers

The Journal of Biogeography aims to support early career researchers by highlighting their recently published journal articles and providing a space where the community can get to know the authors behind the works and learn from their publication experiences. In our featured posts, researchers dive into the motivations, challenges, and highlights behind their recent papers, and give us a sense of the broader scientific interests that drive their biogeographic research. This is where we also get a sneak peek into novel and interesting research that is yet to come!

Based on the information provided when manuscripts are submitted, the editorial team will routinely contact authors each month to invite a contribution from those who are both (1) early career researchers, i.e. up to and including postdocs, and (2) corresponding author on their upcoming publication in Journal of Biogeography. However, we also welcome contributions from other early career researchers who may be first or middle authors on these papers; if the study has multiple authors, we very much welcome a single submission from the cadre of early career co-authors involved.

To keep the process simple for all involved, we invite contributions to follow a standard format (see below). Responses need not be given to all prompts, but there should be a critical mass of responses to be informative; responses to prompts that are answered should be concise; thus the experience is streamlined, personalized, and easy.

We encourage a tone and standard suitable for social media and that conveys the excitement and intrigue of being a biogeographer.  Previous submissions can provide a guide for your own individualized entries.  The social media editors are happy to provide feedback and assistance in revising content before posting.  The senior editorial team approves all posts.

If you have any questions or would like to submit your own contribution, please contact one of our social media editors: Dr. Leanne Phelps and Dr. Joshua Thia using the journal’s gmail address, jbiogeography@gmail.com. To help you get started, the questionnaire is provided below. Check out recent contributions for examples and ideas!

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Questionnaire format:

Name

Links to social media and/or personal website(s)

Institute

Current academic life stage (Honours, Masters, PhD, Postdoc?) 

Major research themes and interests

Current study species/system? What makes it interesting (/cool!)? (100 words)

Recent paper in Journal of Biogeography (citation)

Describe the motivation behind this recent paper (100–150 words)

Describe the key methodologies in this recent paper, highlighting anything particularly novel or ingenious and how this provides new insights (100–150 words)

Describe any unexpected outcomes of this research, or any challenges you and your coauthors experienced and overcame along the way (100–150 words)

Describe the major result of this recent paper and its contribution toward the field (100–150 words)

What is the next step in this research? (100 words)

If you could study any organism on Earth, what would it be and why?

Is there anything else you would like to tell us about yourself or your featured research? (Any hidden gems the above questions might have missed?)

If available, please provide three or more visually appealing photos (with captions) that relate to your work, so we can feature you on our social media platforms.

Featured

Introducing: Highlighted Papers

Every month, each new issue of the Journal of Biogeography (JBI) includes at least two highlighted articles—the Editors’ Choice and the paper associated with the cover image—and periodically we highlight a topic with a series of papers as part of a special issue. Our intention on the blog is to communicate additional aspects of these, and other papers published in JBI, from slightly different perspectives.

Every published paper has a story behind it that complements and enriches our understanding of the published science. Very rarely, the parallel narrative might provide as radical a reframing of the entirety of our scientific work as did Thomas Kuhn’s “The Structure of Scientific Revolutions”, Bruno Latour’s study of “Laboratory Life”, and the feminist critique of science by Evelyn Fox Keller, Sandra Harding, Helen Longino, and others. On occasion it may cause us to rethink the history of the discipline and its modern consequences—as in recent works on decolonialization of biogeography—or likewise to consider current approaches and what they may mean for the future. Oftentimes the parallel narrative is simply a personal perspective on how we stumbled upon a particular question, co-opted a tool for a different job, ran into unexpected difficulties or found something easier than anticipated, visited wonderful places, worked with fascinating organisms and systems, became aware of related challenges, saw something on the side that sparked our curiosity for the next study, and so on.

Irrespective of what your story is, these pages are intended to provide a small window onto that complimentary narrative that details the human endeavor of biogeography. The idea is to try to demystify how the polished published biogeographical story emerges from at times complicated studies of a complex world. No matter what our career stage, each study comes with its challenges, the solutions merit acknowledgement (and can potentially help others), and each publication is an achievement to be celebrated. In recognizing these commonalities, we hope the diversity of routes and strategies for publishing become a little more transparent and a little more accessible to all.

The format for highlighting papers is flexible (within a limit of ~750 words [+/- 250]), but we provide a few optional prompts below to get you started and make sure some key information is available.

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Format & some optional prompts:

Title for blog post

Author name, title, institutional details

Links to social media and/or personal website(s)

Citation including URL for recent paper in Journal of Biogeography 

Describe the motivation behind this recent paper.What’re the major research themes and interests it addresses? — What makes it interesting/cool/important? What surprised you / the team while designing, conducting, completing the study? What knotty problem did you have to overcome? — Reflecting on the whole process, beyond the published research, what were other important outcomes from the project? Where do you / the team go from here? Is there anything else you would like to tell us (any hidden gems the prompts might have missed)?Two to three visually appealing photos/images (with captions) that relate to the work and this narrative is possible.

ECR feature: André Vicente Liz on lizard diversity across the hyper-arid Sahara Desert.

André is a PhD student at the Research Centre in Biodiversity and Genetic Resources, Portugal. He is an ecologist with special focus on biogeography, for which he combines historical and conservation perspectives. Here, André shares his recent work on the evolution of lizards inhabiting the most arid habitats of the Sahara Desert.

André during his Ph.D. sampling in the ergs (sand dune fields) of Ouarane, Mauritania.

Personal links. Researchgate | GoogleScholar | Institution | Facebook

Institute. CIBIO/InBIO, ​Research Centre in Biodiversity and Genetic Resources, University of Porto.

Academic life stage. PhD student.

Major research themes. Biogeography and phylogeography interface between comparative and conservation approaches. During my Ph.D. (ongoing), I investigate spatial biodiversity patterns in the Sahara Desert, aiming at (1) understanding the origin of the desert’s unique fauna and (2) synthesizing knowledge that can be used to minimize the impacts of the unprecedented climatic emergency on species’ persistence.

Current study system. Because they are intensely arid and bare, Saharan hyper-arid habitats (like the dune “erg” fields) appear to be virtually devoid of life, but such empty-desert rule is to some extent misleading given that some organisms successfully persist within these habitats. Beyond desert-flagship invertebrates (such as scorpions and beetles), the best example are spiny-footed lizards, Acanthodactylus scutellatus complex. These are conspicuous and widespread dwellers of sandy fields, wherein they have thrived for millions of years under extreme dryness thanks to their remarkable tolerance towards aridity constraints. These singularities make spiny-footed lizards unique pieces to understand the Sahara puzzle.

Vegetated patches and rocky outcrops contrast with the endless desert sand. Photo Credits: José Carlos Brito.

Recent JBI paper. Liz, A. V., Rödder, D., Gonçalves, D. V., Velo‐Antón, G., Tarroso, P., Geniez, P., Crochet, P.-A., Carvalho, S. B., & Brito, J. C. (2022). Overlooked species diversity in the hyper‐arid Sahara Desert unveiled by dryland‐adapted lizards. Journal of Biogeography 23(1), 101–115. https://doi.org/10.1111/jbi.14510

Motivation behind this paper. We know very little about hyper-arid habitats in the Sahara Desert, despite the area’s vastness (it is larger than the whole Australian continent!) and key role in global dynamics (like dust exportation to feed the Amazon rainforest). Indeed, filling existing knowledge gaps is important from both a natural-history and conservation perspective; first, because the paleoclimatic cycles that affected the desert’s extent make it a unique natural system to understand biodiversity responses to steep environmental shifts; and second, because the expected drastic impact of global warming in the region urges efficient measures to protect its unique wildlife. These reasons led us to study the biogeography of spiny-footed lizards, bearing in mind that, through the analysis of present-day species’ distribution and evolutionary patterns, we could infer historical landscape dynamics (such as shifts in sandy habitats and surface humidity) and verify the magnitude of regional biodiversity shortfalls (how many species have not been properly described?).

Key methodologies. One strength of this paper was the integration of different methodologies, namely ecological modelling, phylogeography and population genetics, to obtain a rather complete picture of the evolutionary history of spiny-footed lizards across the Sahara, and partially overcome sampling biases towards the more accessible areas. For instance, through ecological modelling and spatial interpolations of genetic data, we were able to obtain information from unexplored areas – which species are likely to occur therein? where should we expect higher diversity?

Specimen of Long Fringe-fingered Lizard, Acanthodactylus longipes, a conspicuous dweller of Saharan ergs. Photo Credits: José Carlos Brito.

Unexpected challenges. Certainly, the main challenge was to compile a representative set of samples that were relatively well distributed across the Sahara, considering that it would take us ages to survey the whole region or reach remote areas far from the main human settlements. The Sahara spans over 10 countries, some of them affected by long-lasting armed conflicts and political instability, which adds another layer of difficulty to field campaigns. To solve these issues, we focused sampling on the most accessible hyper-arid habitats, which could be reached in “only” a few days of driving, and by complementing it with natural-history collection samples. Finally, after over a decade of intermittent fieldwork and countless car breakdowns, we were able to build a rich dataset of ~700 samples to start the analyses.

Major results. The most exciting result was the amount of diversity still to be described from the group, which we had far underestimated. Even for taxa that are linked to habitats that are super common in the Sahara, most widespread “species” are in fact a collection of range-restricted species. You take sand specialists, there is sand everywhere and they are present everywhere, yet they have diverged (mostly until speciation) to a level totally crazy! And yet some candidate species are going from the Red Sea to nearly the Atlantic coast… This is very interesting both in terms of natural history (which environmental/geological mechanisms are responsible for such great diversity and connectivity?) and conservation (because the hyper-arid Sahara harbours many more species than what is often realised).

Next steps for this research. I would like to dig more into the biogeographic role of hyper-arid habitats in shaping local species structure, especially during “Green Sahara” phases – did sandy/gravel lowlands become the single pockets of suitable habitats for dryland specialists? were mountains more efficient shelters instead? or was it a mix between these two scenarios, where species persisted in the edge of hyper-arid habitats? are there differences according to functional groups (for instance, would reptiles and arthropods show the same trend)? Understanding these issues would help clarify the ecological value of these historically neglected habitats in the origin of the desert’s unique diversity.

An old truck near Bir Moghrein, which could not make it through the harsh desert conditions. Photo Credits: José Carlos Brito.

If you could study any organism on Earth, what would it be? I am fascinated by tropical habitats and the explosion of life present therein. Prior to my Ph.D., I spent two years in southern Brazil; this experience really marked me both at the professional and personal level. There, I learned to appreciate the symphonic communities of the Atlantic Forest, but also became aware of the conflicting context of dramatic environmental destruction that imperils their perpetuation. I would love to move back there one day and contribute to the conservation of these habitats.

Poor flyers in the sky (-islands)

“As with mariners shipwrecked near a coast, it would have been better for the good swimmers if they had been able to swim still further, whereas it would have been better for the bad swimmers if they had not been able to swim at all and had stuck to the wreck.” (Darwin 1859)

Above: Chorthippus cazurroi (Bolívar, 1898) is a grasshopper that inhabits the summits of the eastern Cantabrian Mountains (Spain); photograph by Eva de Mas.

This metaphor, although in quite a different context, nicely introduces our paper on mountain organisms (Laiolo et al. 2023). In mountaintops, local conditions — strong winds, chilling temperatures — are hardly suitable for flying, especially for small ectotherms. Given that resources are limited, it would be more advantageous to invest in other traits and process rather than in wings and dispersal. In our study we have found that grasshoppers and bumblebees have progressively shorter wing span from lowlands to mountaintops. This reduction is especially marked in grasshoppers, with many flightless species inhabiting high elevations (Fig. 1). The resources saved from wings are partly invested in other life-history traits: eggs get larger, at the advantage of offspring survival.


The grasshopper Podisma carpetana is endemic to Central and Northern Spain and only inhabits mountainous areas. The male (in this picture) and the female have vestigial wings and do not fly. Photo by Eva de Mas.

This result illustrates the adaptations that two phylogenetically distant insect groups (Orthoptera and Hymenoptera) have evolved. Nonetheless, wings serve to disperse, and the dispersal limitations of highland insects have consequences for populations and communities. This limitation affects alpha and beta diversity, and reduces the interchange of species between peaks but not that from lowlands to peaks. As the climate warms, mountain habitats could rescue species from lower elevations, as these species are like Darwin’s “good swimmers”. A nearby mountain, however, cannot rescue a mountaintop species, since peak-to-peak rescues assume that the species can get there, and these are “stuck to the wreck”. Therefore, the fate of these species depends on other mechanisms, such as persistence in climatic refugia or evolution.

Editors’ choice article: (Free to read online for two years.)
Laiolo, P., Illera, J. C., & Obeso, J. R. (2022). Stuck on top of a mountain: Consequences of dispersal limitations for alpine diversity. Journal of Biogeography 50:282-290. https://onlinelibrary.wiley.com/doi/10.1111/jbi.14513

Our main aim was to determine to what extent mountains are true islands for the organisms that inhabit them. We highlighted a powerful influence of the elevation gradient in individual wing variation, and in the strength of environmental filters. We linked trait-based processes at the species level to emergent features of communities, such as alpha and beta diversity, and their spatial patterns, connecting evolutionary, ecological and biogeographic theory.


A view of Cantabrian Mountain peaks emerging from a sea of clouds. Photo by Paola Laiolo.).

In the end, at least for these insects, are the tops of mountains true islands? We cannot say they are, as they receive immigrants from the sea (the valleys). However, insect populations up there do live isolated by a sea of air … or of water vapor.

Written by:
Paola Laiolo
Biodiversity Research Institute (Spanish National Research Council, University of Oviedo, Principality of Asturias), Spain

Additional information:
paola.laiolo@csic.es
https://www.unioviedo.es/IMIB/laiolo-paola/

Vegetation on Mt. Teide (Tenerife) during Humboldt’s time and now

Using historical records to reconstruct how species presence/absence and altitudinal ranges have changed between 1815 and today.


Above: The northern slope of Tenerife island, with the Orotava valley, The sea of clouds and the Teide peak (3718 m,) climbed by Humboldt & Bonpland (1799) and von Buch & Smith climbed (1815) (Photo: José María Fernández-Palacios).

Humboldt’s most famous illustration undoubtedly is his Tableau physique des Andes, which came out in a French and a Germany version in 1807. Encouraged by the success of this illustration, and wanting to further cement his role as a leading biogeographer, he was interested in applying his concept of distinct altitudinal belts to other high mountains. A natural candidate was Mt. Teide, which he and Bonpland had visited late June 1799, at the beginning of their long voyage.

Editors’ Choice: (free to read for 2 years)
Renner, S. S., R. Otto, J. L. Martín-Esquivel, M. V. Marrero-Gómez, J. M. Fernández-Palacios. 2022. Vegetation change on Mt. Teide, the Atlantic’s highest volcano,inferred by incorporating the data underlying Humboldt’sTableau Physique des Iles Canaries. Journal of Biogeography 50(2). DOI: 10.1111/jbi.14503

Humboldt and Bonpland spent only six days on Tenerife and made only 16 collections of which six come from the Teide. None of their 16 collections are linked to precise elevations, which is readily understandable because measuring the altitude of a place above sea level involved complicated formulas to convert air pressure from barometer readings into height a.s.l. Nevertheless, Bonpland collected a violet at the crater rim and observed that it was the highest-occurring flowering plant they saw. 

To achieve his goal of linking plant occurrences to altitudes on the Teide, Humboldt had to rely on collections and measurements made by his close friend Leopold von Buch (1774-1853) and the Norwegian botanist Christen Smith (1785-1816), who together visited the Canary Islands and climbed the Teide twice, taking slightly different routes.



Las Cañadas plain ca. 1830, in the route to the Teide ascension from Orotava valley. It can be seen the sparse vegetation existing, product of the herbivory pressure of introduced goats and rabbits (Source: J.J. Williams).

Our study explores how species presence/absence and altitudinal ranges have changed between 1815 and today. We relied on von Buch’s letters to Humboldt, two book-length studies by von Buch, Smith’s diary, and herbarium material Paris, Berlin, London, Copenhagen, and Oslo. The 224 plant names for 179 species shown at different altitudes in Humboldt’s drawing of Mt. Teide by themselves are unreliable because many of them are shown several times are different altitudes, without any explanation.

Based on old maps, roads, and landmarks, we reconstructed the two paths up the Teide taken by Buch and Smith on 18 May and on 25 August 1815. We then compared modern elevation data come from the Canary Is. Biodiversity Data Bank, which includes records for animals and plants in 500 x 500 m Universal Transverse Mercator grid cells, with the occurrences that Buch and Smith noted. These comparisons were only possible because of the extensive local knowledge of members of our team, especially José Maria Fernández-Palacios, José Luis Martín Esquivel,and Manuel V. Marrero-Gómez, who have worked on the fauna and flora of the Teide park for many years.


The Teide peak (3718 m, the highest elevation in the Atlantic Ocean) seen from the south (Photo: José María Fernández-Palacios).

Climate warming on Tenerife is occurring rapidly, with an average temperature increase of 0.14 ± 0.07oC/decade between 1944 and 2010 in the Teide summit region, twice as fast as the rest of the island. However, many abiotic factors have also changed since 1799/1815. Since the establishment in 1954 of the Teide National Park, timber cutting has been prevented and goats, which were abundant during Humboldt’s time, have been eradicated. Other animals, however, have increased in abundance, including European rabbits and European mouflon sheep.

These multiple biotic and abiotic changes made it almost impossible to securely assign cause and effect for the drastic changes in species presence/absence and upper range limit that we found in the 23 species for which the 1799/1815 observations could be georeferenced with sufficient precision. Species have shifted upward, with the average shift being 36.4 m per decade, and four species that today are abundant were not recorded in 1815, suggesting population expansion, probably due to goat eradication.

In many ways, the project was frustrating because of the imprecision of the historic data. Among the outcomes is a list of the species seen in 1815, with up-dated taxonomy and notes (available as online supporting material), and this might in the future be useful for ecological studies of particular species on the Canary Islands.

Written by:
Susanne Renner
Department of Biology, Washington University, Saint Louis, Missouri, USA


Las Cañadas zone ca. 1830, with a goat and her calf and a beehive, indicative of the important use given to this part of the island at that time (Source: J.J. Williams).

ECR feature: Jeff Stallman on mushrooms and the theory of island biogeography

Jeff Stallman is a PhD candidate at the Purdue University. He is particularly interested in the taxonomy, systematics, and biogeography of macro-fungi, with an emphasis on the Hawaiian Islands. Here, Jeff shares his recent work on mushrooms endemic to oceanic islands and how they fit in with the theory of island biogeography.

On a collecting trip with his lab at Purdue University, Jeff was happy to find a large Amanita species in southern Indiana.

Personal links. Twitter.

Institute. Purdue University, Indiana, USA.

Academic life stage. PhD candidate.

Major research themes. Fungal taxonomy, biogeography, and conservation.

Current study system. For my PhD, I study Leotiomycetes. This class of fungi in the Ascomycota contains fungi that cause powdery mildew in plants and white-nose syndrome in bats, among many other lifestyles. I focus on small cup-shaped fungi in the order Helotiales, particularly from tropical locations where little sampling has been done. I use DNA sequence data from these collections to improve our systematic understanding of the order. Currently, the number of described species is far below the estimated diversity (as is true for most fungal taxa) and there are an estimated 90–151 incertae sedis genera in the order.

Recent JBI paper. Stallman, J. K., Robinson, K., & Knope, M. L. (2022). Do endemic mushrooms on oceanic islands and archipelagos support the theory of island biogeography? Journal of Biogeography, 00, 1–11. https://doi.org/10.1111/jbi.14517

Motivation behind this paper. I worked as a field technician in various conservation jobs in the Hawaiian Islands. During these jobs, and while pursuing my MS degree at the University of Hawaiʻi Hilo, I became quite obsessed with Hawaiian plants. I loved seeing them in the wild and learning about their unique evolutionary and biogeographic histories. For several reasons, data with the same level of detail on plants was not available for Hawaiian mushrooms (Agaricomycetes). So, we set about gathering these data to see if Hawaiian mushrooms followed similar biogeographic patterns as plants.

Key methodologies. We use a traditional checklist-based method in this paper. We updated a checklist of Hawaiian mushrooms, then used checklists of angiosperms, ferns, lichens, bryophytes, and mushrooms from Hawaiʻi, Canary Islands, Azores, Cabo Verde, Galápagos, Madeira, and Christmas Island to compare endemic species in different organism groups among and between different islands and archipelagos.

Photographing fungi in MacKenzie State Recreation Area in the Puna District of Hawaiʻi Island. Mushrooms are often abundant in the litter of the introduced Casuarina trees.

Unexpected challenges. I didn’t know what to expect, so everything was unexpected! The main challenges were dealing with limitations in the data that are inherent to checklists and studies of biogeography. Our knowledge of species diversity and distributions is incomplete, particularly in cryptic groups such as mushrooms, and DNA sequence data is lacking in most fungi from these locations on these checklists. In the end, many species could not be assigned to a known category (non-native, native, native and endemic), so they needed to be excluded from the analysis. These and other limitations are discussed in a (long) limitations section in the paper!

Major results. We provide baseline evidence that mushrooms follow similar island biogeographical principles to plants. For example, percent endemism in mushrooms is positively correlated with island size and distance to mainland. But we did not find evidence that maximum elevation or a closer proximity to the equator was correlated with increased endemism percentage. There has been recent interest in this topic in general, and we hope our research can be built upon and used as an argument to gather more data in the future. This adds to evidence accumulating over the last 30 years that in many cases microbes are dispersal-limited, in contrast to the ideas of the Baas-Becking hypothesis that “everything is everywhere, but the environment selects.”

A container of colorful collections from a walk in Cusuco National Park, Honduras.

Next steps for this research. Continuing with the same methodology, checklists from the seven islands and archipelagos can be updated, and checklists from more islands/archipelagos can be added to improve sample size. More DNA sequence data on fungi from these islands and archipelagos would also help with quick comparisons via global databases. Particularly, incorporating DNA data to explore anagenesis (evolution of a single endemic species from its ancestral continental counterpart) versus cladogenesis (diversification into multiple, endemic species after establishment on an island or archipelago) would improve this aspect of the analysis. Public databases such as Globalfungi and the Global Soil Mycobiome consortium have exciting potential in addressing these questions.

If you could study any organism on Earth, what would it be? Tough question! The putative Hawaiian endemic Hygrocybe noelokelani is a beautiful mushroom and there seems to be a pattern of endemic Hygrophoraceae on oceanic islands, so I would pick that species, or the family on islands/archipelagos more broadly.

ECR feature: Julian Schrader on plant functional traits and the Equilibrium Theory of Island Biogeography

Julian Schrader is a postdoc at the Macquarie University, Sydney. He is an ecologist with special interest in plant functional ecology, biogeography and conservation biology. Here, Julian shares his recent work on functional traits in relation to the Equilibrium Theory of Island Biogeography.

Fieldwork: Julian is fascinated by life on small islands even though field work can be quite space-limited sometimes (small island in Raja Ampat Archipelago, Papua, Indonesia; see also Schrader et al. 2021 Journal of Biogeography).

Personal links. Website | Mastodon

Institute. School of Natural Sciences, Macquarie University, Sydney, New South Wales, Australia.

Academic life stage. Postdoc.

Major research themes. Ecology – Biodiversity – Biogeography – Ecosystem Functioning – Nature Conservation

Current study system. The core idea of this paper was to extend MacArthur and Wilson’s famous Equilibrium Theory of Island Biogeography (ETIB) to functional traits and test whether community trait values remain constant over time, similar to species richness, as predicted by ETIB. ETIB is among the most influential theories in ecology. Testing its core assumptions for traits for the first time was very exciting.

Recent JBI paper. Schrader, J., Wright, I. J., Kreft, H., Weigelt, P., Andrew, S. C., Abbott, I., & Westoby, M. (2023). ETIB‐T: An Equilibrium Theory of Island Biogeography for plant traits. Journal of Biogeography, 50(1), 223-234. https://doi.org/10.1111/jbi.14526.

Motivation behind this paper. Functional island biogeography – the integration of trait ecology to island biogeography – is a relatively new but rapidly expanding research field. Core ideas of functional island biogeography include testing whether island community assembly can be explained by species traits rather than species richness. ETIB provides the conceptual background for countless island studies and extending ETIB to traits has long been a research focus of our team. However, major advances have so far been hindered by lack of temporal data needed to test ETIB for traits. Repeated vegetation sampling over longer time spans is scarce in island ecology, especially when also trait data are needed. With the island vegetation surveys done by Ian Abbott and colleagues from the 1960s to 1990s on small islands off Perth in Western Australia and the recent AusTraits database (a trait database for Australian plant species), we could finally test whether island community trait values remain constant over time irrespective of local species immigrations and extinctions.

The Perth Archipelago includes many small to medium seized islands. The islands’ small size and often high disturbances by waves and wind lead to high local immigration and extinction events. Small plant species with small seeds are more likely to establish but also have higher local extinction risk.

Key methodologies. We used simple statistics to test whether community trait values and functional diversity remain at equilibrium over time. The patterns we found are thus easy and intuitive to interpret, clearly showing that ETIB can be extended to functional traits. Our simple analytical approach also makes the study easily repeatable in other archipelagos, hopefully leading to further insights from other regions, species and traits. Fortunately, all data needed for this study were available in published papers. This allowed us to extract data remotely and write-up the manuscript during the height of the covid-19 pandemic.

Unexpected challenges. The biggest hurdle of this research was certainly the covid-19 pandemic. None of the initial co-authors has ever visited the small islands off Perth, which made ecological interpretation of the results difficult. Fortunately, Ian Abbott was keen to join our team and help interpreting the pattern. Ian is a highly experienced island ecologist and has visited countless of the small islands in Western Australia since the 1970s. Also, some of the species occurrence data were collected by Ian. After the pandemic, I had the chance to visit some of the studied islands myself at last.

Major results. This study is the first, to the best of our knowledge, to test for temporal trait changes and trait equilibria on islands. We found that community trait values and functional diversity remain constant over time despite very high species turnover, which was as high as 60% in some islands. Further, we found that species most susceptible to turnover were on average smaller and had lower seed mass than persisting species. These results provide evidence that ETIB is extendable to functional traits.

Next steps for this research. I would certainly like to test the Equilibrium Theory of Island Biogeography for Traits at larger biogeographical scales. That is, to test whether the same patterns we found on the small island off Perth also occur across different archipelagos worldwide and under varying geo-environmental factors. For that, I would like to motivate colleagues and other island enthusiasts to revisit and resample islands studied in the past. It may also be interesting to test whether global change, in the form of climate warming and rising sea levels, has an impact on community trait composition on islands. This is something I would like to test in the near future.

If you could study any organism on Earth, what would it be? I would again turn my attention towards islands and their unique biodiversity. Islands are wonderful study systems and fun to visit and work on. I am especially fascinated by small islands as the ecological mechanisms maintaining their biodiversity can be studied and understood in detail and still yield novel and surprising results.

The largest island of the Perth Archipelago – Rottnest Island or Wadjemup – also supports a large variety of wildlife like this endangered Quokka (Setonix brachyurus). Luckily, on Rottnest Island Quokkas are still common.

ECR feature: Robert Weigel on growth synchrony and climate change-sensitivity in European forests

Robert Weigel is a postdoc at the University of Göttingen. He is a geoecologist with special interest in forest ecosystems. Here, Robert shares his recent work on climate sensitivity and within-stand synchrony of growth in a European beech–oak ecotone.

Robert Weigel (Photo Credits: Banzragch Bat-Enerel).

Personal links. Twitter.

Institute. University of Göttingen, Plant Ecology and Ecosystems Research.

Academic life stage. Postdoc.

Major research themes. Responses and adaptation mechanisms of trees and forest ecosystems to changing climate across seasons.

Current study system. Temperate forest trees, such as European beech, Scots pine, European oak species. Trees are cool study systems on their own, but studying these species is now a very hot topic because foresters urgently need advice on which tree species to choose for climate smart forestry.

Recent JBI paper. Kasper, J., Leuschner, C., Walentowski, H., & Weigel, R. (2022). Higher growth synchrony and climate change-sensitivity in European beech and silver linden than in temperate oaks. Journal of Biogeography. https://doi.org/10.1111/jbi.14525

Motivation behind this paper. European beech, the naturally dominant tree species in Central Europe, was long considered to be fairly climate-change resilient. However, severe defoliation events, e.g., the extreme hot drought in 2018, highlight the species’ potential drought vulnerability. Admixing more drought-resilient, thermophilic oak species might be a promising option to promote more drought resilient forest ecosystems closer to the near-natural state, compared to introducing exotic timber species. To directly compare the drought resilience of different species, we analysed growth dynamics in beech and oak populations in close proximity.

Key methodologies. We analysed tree-ring series in order to explore the climate–growth relationship of our study populations. As a quite novel approach, we rely on the strength of regional synchronization in tree growth dynamics as an indicator for climate change-induced abiotic stress, instead of only quantifying the drought signal in the tree-ring series by correlating annual increment rates with time series of various factors. The advantage of this synchrony analysis is that it summarizes across the isolated, non-stationary effects of the various climatic drivers of tree growth rates.

Samples of wood are the basis of our study. These samples were taken from European beech. They are glued to wooden strips and prepared with razor blade or sandpaper so that the annual rings are clearly visible on the smooth surfaces and can be measured and dated using a microscope (Photo Credits: Stella Gribbe).

Unexpected challenges. In the beginning, we did not anticipate how clearly the synchrony patterns would differ between the species. With the onset of the strong warming in the 1980s, growth synchrony clearly increased in European beech and silver linden, while it clearly decreased in the studied Central European to Pannonian oak species, although the synchrony patterns where quite similar before that time.

Major results. We think that, for increasing climate change resilience of forests, it may be wise to favour more stress-tolerant over high-yield timber species in vulnerable regions. The three studied oak species produce highly valued timber and would be a promising option for the transition to climate-smart forestry.

View into beech (left) and oak (right) forests in the study area in Western Romania (Photo Credits: Jan Kasper).

Next steps for this research. We are currently transferring the research to South America (Patagonia) in order to explore if we can find similar divergence in drought response and synchrony patterns when comparing among different southern beeches (Nothofagus). Here, less is known about how the drought resistance changes among species, especially when comparing to fast-growing introduced conifers.

If you could study any organism on Earth, what would it be? I have no preference for any study organism in particular. I would like to stay with studying temperate forest ecosystems, because we urgently need a sound and locally precise understanding of climate change-related stressors for tree growth, in order to provide precise suggestions for climate-smart forestry. Of course, the best advice for sustaining healthy forests is to reduce greenhouse gas emissions and slow down the climate change velocity as fast as possible!

Anything else to add? Climate change means not only hotter and drier summers. This being bad enough, temperate and boreal winters are also changing dramatically. Due to winter warming, the insulating snow cover may decline or vanish, which increases soil frost exposure to tree roots and the microbial community in the forest floor in some regions, while in other, somewhat warmer regions frost might become absent completely. These aspects have to be considered by studying climate change impacts across seasons instead of focussing on the growing season only!

ECR feature: Patricia Wepfer on the evolution and population dynamics of reef-building corals

Patricia H. Wepfer is a postdoc at the Institute of Spatial and Landscape Development, ETH Zurich. She is broadly interested in biogeographic processes shaping species distribution patterns. Here, Patricia shares her recent work on the evolution and population dynamics of reef-building corals from the North-Western Pacific.

Patricia Wepfer collecting coral polyps at site Oku, Okinawa Island

Institute. Institute of Spatial and Landscape Development, ETH Zurich.

Academic life stage. Postdoc.

Major research themes. Geographically driven evolution; population connectivity; urban design and architecture

Current study system. Reef-building corals are fascinating in that they are animals but are plant-like in many aspects. They live on photosynthesis products provided by their symbiotic dinoflagellates, which helped them to become the successful reef-builders they are today. Their dispersal resembles wind-dispersed plants, as their larvae travel passively with ocean currents. With the ability to model ocean currents, it is extremely interesting to study dispersal-related questions in pelagic dispersers. Corals belong to the Metazoa and are ancient creatures with unclear species boundaries in the current taxonomy. However, Galaxea is a large-polyped coral that is fluorescently green and is therefore easy to identify, which makes it a good target to study the history of a self-contained evolutionary group.

Ogasawaran lineage of Galaxea fascicularis from around Chichi Island

Recent JBI paper. Wepfer, P. H., Nakajima, Y., Fujimura, A., Mikheyev, A. S., Economo, E. P., & Mitarai, S. (2022). The oceanographic isolation of the Ogasawara Islands and genetic divergence in a reef-building coral. Journal of Biogeography 49 (11), 1978–1990. https://doi.org/10.1111/jbi.14475

Motivation behind this paper. The Ogasawara Islands are an interesting island system because of their exceptional degree of isolation. They are oceanic volcanos, hundreds of kilometres away from the next continental land masses or island groups. Due to the lack of major ocean currents passing them, they are oceanographically even more isolated than the Galapagos islands. That our coral taxon was the most common and dominant reef-builder in the coral community on this archipelago, unlike in all Asia and Australia, additionally made this site a must-visit on our sampling list for our connectivity study.

Cliffs at the Southern coast of Chichi Island

Key methodologies. We combined high-throughput sequencing (RAD-seq) with a novel inverse particle tracking approach in our study. The loci obtained from RAD-seq enabled the investigation of an evolutionary time scale by looking at the demographic history, while the biophysical dispersal model was able to identify contemporary oceanographic dispersal patterns. By linking the two we found that the coral around the Ogasawara Islands have been isolated like today for a very long time. It implies that even for well-dispersed marine animals, geographic isolation can be linked to high degrees of differentiation and diversification of a taxon.

Unexpected challenges. As usual with corals, it was challenging to collect them. Due to their vulnerability, it is important to collect minimal amounts while gathering enough to ensure a good sample size. It was challenging also to go through the administrative procedure to travel to such a remote place, involving multiple days of travel on a rolling ship.

Major results. It was unexpected that we would find such a highly differentiated lineage on Ogasawara. We thought that the Ogasawaran coral must be somewhat connected to the Mariana Islands, since the alternative dispersal route was over temperate climate zones. However, it turned out that this archipelago hardly receives any migrants from the South, and only rarely from the North. Whether other marine animals follow similar patterns is still unclear, yet our results allow us place the hypothesis that the endemicity under water could be as high as on land, for which the Ogasawara islands are already famous for.

Next steps for this research. The next step will be to further investigate the oceanographic patterns in this region. The dispersal modelling will be refined including more potential stepping-stones along this island chain and isolated solitary islands to the West. From the genetic side, it will be important to sample more in Guam to verify the genetic composition there, as well as specimens from the Northern Mariana Islands for a more detailed analysis of the connectivity between the archipelagos.

If you could study any organism on Earth, what would it be? There isn’t a particular organism on my mind, but I would probably continue studying more different coral species and their distribution around Western Pacific Islands. Although it was challenging to study their evolution because species boundaries are so vague and much less understood than for example in plants. Sampling procedures are also hard because of their CITES status. For these reasons, I would also consider switching back to plants. However, I now switched to an entirely new field: urban planning and architecture – maybe this could be considered studying the microecology of the human species.

Anything else to add? The visit to the Ogasawara Islands was definitely a highlight of my PhD. I visited many islands but the Ogasawara Islands felt especially wild and natural, thanks to their comprehensive environmental protection. It is a place where turtles are unimpressed by human presence and dolphins curiously swim up to one.

Sea turtle resting on the coral reef between Anijima and Chichijima

Overcoming challenges in measuring how seed dispersal and climatic niche evolution are connected in plants

In this blog post, I discuss some of the “behind the scenes” factors in writing “Linking mode of seed dispersal and climatic niche evolution in flowering plants”, including our main motivation and some challenges we had to overcome with data curation and trait evolution modeling in the project

Above: Miconia sp. (Melastomataceae), a diverse lineage of flowering plants with fleshy fruits and biotically dispersed seeds in tropical forests; Photograph by Vanessa Staggemeier.

My co-authors and I started talking about writing a paper linking mode of seed dispersal and climatic niche evolution during the Covid-19 pandemic lockdown in 2020. At the time, I was reading a lot of the classic literature on plant biogeography and, led by Jeremy Beaulieu, we were all working on developing new models to better understand plant macroevolution in a quantitative way. Inspired by the interdisciplinary synthesis of Stebbins (1974), I became particularly interested in understanding how certain traits are important modulators in the biogeography of plants which, as sessile organisms, move in space mainly during seed dispersal, and so seed dispersal should have a strong impact on their spatial distribution. For example, it had been suggested that species with biotically dispersed seeds tend to be more common in warmer and wetter environments and that the behavior of frugivores that disperse their seeds would lead these lineages to have slower rates of climate niche evolution over time.


Reasoning behind one of the hypotheses tested in our study. (a,b) Dry fruits are used as a proxy for abiotic seed dispersal, whereas fleshy fruits are used as a proxy for biotic seed dispersal. (c) Different modes of seed dispersal are expected to impact rates of climatic niche evolution in flowering plants differently, based on the assumption that abiotic factors promote erratic dispersal and increased opportunity for niche shifts through time.

Despite that, we noticed that much of the more recent literature on climatic niche evolution in plants focused mainly on the importance of vegetative traits, such as leaves and woodiness, while fewer investigate reproductive structures, such as flowers and fruits. The few studies that had analyzed the connection between climatic niche evolution and mode of seed dispersal in some capacity did so within a restricted sample of species or in a non-quantitative way. Consequently, it was difficult to tell if certain patterns were general enough to be replicated in many unrelated plant lineages. Conveniently, James Boyko was working on developing new trait evolution models for his PhD at the time and the hypotheses we wanted to test matched perfectly the way in which these models were parameterized. When we heard about the JBI Innovation Awards, we felt that that was the final push we needed to work together on this collaborative project.

Editors’ choice article: (Free to read online for two years.)
Vasconcelos, T., Boyko, J. D., & Beaulieu, J. M. (2023). Linking mode of seed dispersal and climatic niche evolution in flowering plants. Journal of Biogeography. 50:46-53. https://onlinelibrary.wiley.com/toc/13652699/2023/50/1 

In my opinion, one of our most interesting result was that no matter which clade we look at, we always found support for lineages with abiotic seed dispersal shifting to colder climatic optima and lineages with fleshy fruits shifting towards warmer climatic optima. This is true for more temperate clades like Ericaceae as well as more tropical ones like Melastomataceae. We also found some support for lineages with biotically dispersed seeds having slower rates of climatic niche evolution, though in this case the pattern is not as general and the story is perhaps a bit more complicated, as we discuss in the paper. But, to me, that is the main appeal to combine and compare results from multiple lineages under the same analytical framework – we can use these results to set apart rules (patterns observed in most lineages) and exceptions (lineages where the general pattern is not observed) in how biodiversity evolves in space over time.


Optima estimates for temperature (in Celcius) for lineages with different fruit types. Note that the climatic optima of Ericaceae lineages are still significantly colder than those of Melastomataceae, reflecting their global distribution. However, both families still show the same general pattern where lineages fleshy fruits shift to warmer climatic optima. Distribution maps taken from Stevens (2001-onwards).

Regarding challenges we had to overcome, I think two of the most time consuming parts of the project were data curation and improving computational speed for modeling continuous traits. Much of our data had been scored using fruit type as a proxy for mode of seed dispersal. Fleshy fruits, such as berries and pomes, are typically dispersed by frugivore animals while dry fruits, such as achenes and capsules, are typically dispersed by abiotic factors such as wind and gravity. However, this is an often simplistic view of how seed dispersal works, and during data curation we had to perform a more thorough literature review of some groups where fruit type did not necessarily correspond to the main mode of seed dispersal. One other problem was the computational time and effort needed to fit our models. Not only were the trait evolution models very complicated, but they needed to be fit many times in each dataset to make sure our parameter estimates were correct. This sort of computational workload was not feasible using standard algorithms available at the time, so my co-authors implemented an algorithm which allowed for the fast calculation of model parameters. The increase in speed is difficult to understate as models which once may have taken weeks to finish, could now be completed in hours!

Today, our team keeps working on similar projects linking trait-evolution and biogeography in plants, and we have several papers to be published soon in the same vein as this. For instance, in Vasconcelos (in press.), I give a brief historical overview of trait-environment correlation analyses and indicate some limitations in our current approaches to quantify rules in plant biogeography. In Boyko et al. (in press.), James and Jeremy developed a new software that improves our current analytical framework. Using this new software, our team is working on answering other trait-environment correlation questions in plants, such as, for instance, what are the evolutionary processes that lead to a prevalence of annual life history strategy in deserts and mediterranean areas (Boyko et al., in review).

Written by:
Thais Vasconcelos
Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA

Additional information:
Twitter: @TNCVasconcelos

References:
Boyko, J. D., O’Meara, B., & Beaulieu, J. M. (in press.). Jointly Modeling the Evolution of Discrete and Continuous Traits. Evolution. Preprint available at: 10.32942/osf.io/fb8k7
Boyko, J. D., Hagen, E. R., Beaulieu, J. M., & Vasconcelos, T. (in review). Long-term responses of life-history strategies to climatic variability in flowering plants. Preprint available at: 10.1101/2022.10.19.512857
Stebbins, G. L. 1974. Flowering plants: evolution above the species level. Harvard University Press, Cambridge, MA.
Stevens, P. F. (2001 onwards). Angiosperm Phylogeny Website. Version 14, July 2017 [and more or less continuously updated since] http://www.mobot.org/MOBOT/research/APweb/.
Vasconcelos, T., Boyko, J. D., & Beaulieu, J. M. (2023). Linking mode of seed dispersal and climatic niche evolution in flowering plants. Journal of Biogeography. 50: 46-53. 10.1111/jbi.14292 Vasconcelos, T. (in press.) A trait-based approach to the rules of plant biogeography. American Journal of Botany . Preprint available at: 10.32942/osf.io/azytc

ECR feature: Georgia Vasey

Georgia is a PhD student at the University of Nevada, Reno, in the USA. She is a plant ecologist with a special interest in conservation and biogeography. Here, Georgia shares her recent work on how the trait variation of a dryland pine species responds to regional climatic gradients.

Georgia enjoying the beautiful petroglyphs at one of her field sites, Mount Irish.

Institute. The University of Nevada Reno (during her recent master’s graduation)

Academic life stage. PhD student at the University of California Santa Cruz

Major research themes. Plant Ecology, Conservation Biology, Restoration Ecology, Biogeography.

Current study system. Driving across the most mountainous and driest state in the U.S., Nevada, you will explore beautiful semi-arid woodlands that dominate the landscape up to the alpine-treeline ecotone. Singleleaf pinyon pine (Pinus monophylla) is a foundational tree species in semi-arid woodlands of the Great Basin and upper-montane environments of the Mojave Desert. Across its wide range, you will see it growing next to giant Joshua trees at the lowest elevations, all the way to establishing the understory of Ponderosa pine and White fir at higher elevations. It is the most xeric pine in the U.S., slow-growing and long-lived (>800 years), with a scrubby, rugged stature. Producing pine nuts, its legacy as the most culturally important plant for the local Indigenous people of the area, as well as a dominant food source for many animals, makes it an important species to research.

Left: Large singleleaf pinyon at the lower site in the San Bernardino Mountains, California. Right: Expanse of singleleaf pinyon pine in the Pine Nut Mountains near Carson City, Nevada.

Recent JBI paper. Vasey, G. L., Weisberg, P. J., & Urza, A. K. (2022). Intraspecific trait variation in a dryland tree species corresponds to regional climate gradients. Journal of Biogeography, 49(12), 2309­-2320. DOI: https://doi.org/10.1111/jbi.14515

Motivation behind this paper. Tree species worldwide are experiencing drought-induced mortality as temperatures steadily rise. A recent drought from 2013–2015 caused eightfold dieback of singleleaf pinyon pine in the central region of the Great Basin, motivating the co-authors P.J. Weisberg and A.K. Urza to apply for funding to better understand the species’ functional limitations and adaptive capacity. Many long-lived species rely on their intraspecific trait variation to manage climate change pressures; however, knowledge of this species was limited. As a foundational tree species in dryland woodlands, large-scale mortality would dramatically alter community assembly and threaten the ecosystem. This paper aims to investigate how much functional trait variation exists within the species’ distribution, and whether it may be enough to withstand future environmental conditions.

Key methodologies. In this research, we obtained samples across singleleaf pinyon pine’s geographic range, both latitudinal and elevational, encompassing local and broad-scale gradients of climate and soil characteristics. At each of the 23 sites, six climate variables were obtained that related to important life-history trade-offs related to drought stress. We measured nine morphological traits, both reproductive and vegetative, for each tree (N = 137). These data, in conjunction with the environmental variables, evaluated (1) how trait variation was partitioned across ecological scale, and (2) the relationship between traits and broad-scale environmental gradients across its range. We also looked at interannual variability for needle size across three growth years compared to annual weather data from 2016–2018 to measure phenotypic plasticity. One of the more novel approaches to this data analysis was using two-block partial least squares analysis (2B-PLS), a newer ordination method to evaluate maximum covariance between two matrices (in this case, traits, and environmental variables). After trying other methods, I found this one to be the most visually interpretable and highly recommend it.

Upper Left: Field helper, Paul Burow, harvesting pine cones from the upper ⅔ of canopy at Mount Irish, Nevada. Lower Left: PPE to manage sticky pine cones when measuring cone length. Right: Research Technician, Erica Sutherland, helping measure cone traits.

Unexpected challenges. As a mast seeding tree species, seed production varies greatly from year to year. We were lucky that 2019 was a good year for sampling singleleaf pinyon pine. While you can clearly observe on Google Earth that the tree is located in a particular area, it’s not until you arrive 10+ hours later at your destination that you officially find out if it’s actively reproducing. Additionally, the window of time that the cones are ripe but haven’t completely opened is short. Trying to harvest enough cones before animals predate them was a race, to say the least. We managed to overcome these obstacles by putting in long days and working systematically. At the greenhouse, I also couldn’t have measured ~25,000 measurements (i.e., nine traits measured multiple times according to their sample size) without the help of two amazing research technicians. These kinds of projects aren’t possible without an enthusiastic and dedicated team!

Major results. The highest proportion of trait variation was explained at the scale of individual trees, suggesting within-population adaptive capacity is possible. However, a substantial portion of variance was also explained at regional scales related to environmental gradients (e.g., seed mass and cone-level seed number in response to aridity, and specific leaf area and needle weight in response to precipitation seasonality), suggesting that certain traits are adaptive in different environments. Additionally, for some foliar traits, our results suggest that singleleaf pinyon pine is phenotypically plastic in response to the environment. Our results inform management decisions on potential assisted migration efforts (e.g., use larger seeds from drier populations), while also suggesting that in situ variation may allow the species to persist without intervention. This paper also highlights that using mean trait values in predictive modelling is not always sufficient and that more research on individual species (particularly foundational ones) merits more attention.

Left: Sticky green pine cones before they open. Right: Compilation of morphological traits: cones, seeds, and needles.

Next steps for this research. Stay tuned for my second chapter in the queue to be published! I conducted a common garden greenhouse experiment with the seeds from each maternal tree to evaluate seedling trait response to a gradient of water availability. I also helped with the establishment of two additional common garden experiments, one using the same seeds in an outdoor site in Carson City, Nevada, and another using the surviving greenhouse seedlings at a site in the Shoshone Mountains. We hope these follow-up studies will provide a better understanding on the traits adaptive value and plasticity, with an emphasis on seedling stage establishment (a known bottleneck period).

If you could study any organism on Earth, what would it be? I’m really excited to currently be working on my PhD in coastal California (my home), studying wildflowers in grasslands. Who doesn’t love these ephemeral beauties that paint the landscape in the spring!?

Anything else to add? I’m so grateful I was advised by two amazing advisors, Peter Weisberg and Ali Urza, during my master’s research. I learned how to be a scientist: ask thoughtful questions, make informed predictions, understand the nuances of experimental design, and everything that happens thereafter from completing the study, data analysis, and writing. We were an excellent team, and I’m excited to continue collaborating! I’m also thankful to Journal of Biogeography for publishing my first paper that I’m the lead author on. If you are interested in my research and would like to learn more or collaborate, feel free to contact me by email (vaseygl@gmail.com).

Singleleaf pinyon pine growing alongside Joshua trees in the San Bernardino Mountains, California.

ECR feature: Pablo Castro Sánchez-Bermejo

Pablo is a PhD student at the Martin Luther University Halle-Wittenberg in Germany. He is an ecologist with a special interest in community and functional ecology. Here, Pablo shares his recent work on how the gradient of aridity drives the loss of taxonomic and functional diversity in dung beetle communities in three different deserts.

The PhD student Pablo Castro Sánchez-Bermejo

Personal links. Google Scholar | Twitter

Institute. German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Puschstraße 4, Leipzig 04103, Germany

Martin Luther University Halle-Wittenberg, Institute of Biology/Geobotany and Botanical Garden, Halle (Saale), Germany

Academic life stage. PhD student

Major research themes. Trait-based functional ecology and community ecology

Current study system. Dung beetles of the Scarabaeidae family primarily use the dung of mammals for feeding and nesting. That is why these organisms are crucial for the decomposition and recycling of dung into the soil. Since this taxonomic group has an important function in ecosystems, these organisms are good proxies for changes in the environment where they live. Also, the responses of this taxonomic group to large-scale environmental gradients are generally well-known, though so far, we know very little about the effects of aridity. Especially, it is urgent to understand the functional diversity responses of this group, which is crucial to better explain ecosystem functioning.

Recent JBI paper. Castro Sánchez-Bermejo, P., deCastro-Arrazola, I., Cuesta, E., Davis, A. L. V., Moreno, C. E., Sánchez-Piñero, F., & Hortal, J. (2022). Aridity drives the loss of dung beetle taxonomic and functional diversity in three contrasting deserts. Journal of Biogeography, 49, 2243–2255. https://doi.org/10.1111/jbi.14506

Motivation behind this paper. Drylands cover more than a third of the Earth’s land mass and are home to more than 38% of the world’s population.  It is alarming that these complex and amazing ecosystems are especially vulnerable to climate change and land degradation. Increased aridity in drylands has been driven by global warming, and therefore studying how ecological communities respond to gradients of increasing aridity remains crucial to understanding the effects of climate change on biodiversity. Furthermore, while the responses of some taxonomic group, such as plants, have been widely studied, we still lack knowledge about the responses of many animal groups to aridity gradients.

Scarabeus sacer in Morocco. This species belongs to the guild of the rollers, which sculpt the dung into a ball using his hind legs and roll it away before burying the dung in the soil. Photo taken by Fernando Urbano.

Key methodologies. In this paper, we characterize dung beetle communities along aridity gradients in three different deserts: Sahara, Kalahari and Chihuahua. We used 20 quantitative and 2 qualitative functional traits that account for dung beetle responses to arid environments to study, not only taxonomic responses but also changes in trait-based functional indices along the aridity gradients. We also attempted to isolate the effect of the different assembly rules (i.e., aridity, biotic interactions and stochastic processes) by using three different null models. One of these null models generates simulated communities randomly from the total species pool in the desert. The other two null models create simulated communities based on the response of species to aridity and the co-occurrence of species, respectively. Finally, by comparing all simulated values with that observed in the desert we could addressed the relative importance of the different assembly rules.

Unexpected challenges. In this research, we were expecting to observe a shift from biotic-driven communities (where the role of biotic interactions in community assembly is highly relevant for the assembly of dung beetle communities) in the semi-arid extremes of the gradient to aridity-driven communities in the hyper-arid areas. However, we found little evidence for similarity-limiting processes in assembling dung beetle communities. Instead, it appears that abiotic factors are the primary assembly rule along the entire aridity gradient.

Scarabeus sacer and Esymus finitumus in Morocco. Photo taken by Fernando Urbano.

Major results. We observed a decrease of both taxonomic richness and functional dispersion along the gradients of increasing aridity. This pattern seems to be the result of aridity, while limiting similarity or stochastic processes do not seem to be of great importance for the assembly of these communities. Also, in addition to the general patterns, it appears that different regional species pools respond to aridity in different ways. As climate change drives increased aridity, future dryland expansion scenarios may result in a decrease in taxonomic and functional diversity, while this would enhance the effect of abiotic conditions as the main filter in the assembly of dryland dung beetle communities.

Next steps for this research. In our recent study, we focused on examining dung beetle communities in three deserts, but to better understand the responses of this group to aridity, future research should include a broader representation of drylands, and even including aridity gradients in cold drylands (e.g., Greenland, the Patagonian Steppe). In addition, other aspects of biodiversity besides taxonomic and functional diversity, such as phylogenetic diversity, is crucial to better represent changes in these communities and the community assembly in drylands.

If you could study any organism on Earth, what would it be? Even though I have experience in plant ecology, and specifically working with trees, I am not very interested in any specific organism or taxonomic group. Instead, I would rather choose groups that I can use as models to test hypotheses in the fields I am interested in (community assembly, biotic interactions, functional diversity). This is why I am not afraid to work with different taxonomic groups, including plants, dung beetles, and hopefully, other organisms in the future.

Infographic summarizing some of the results in the paper. Illustrations were prepared by the PhD student.