Dimensions of amphibian alpha diversity in the New World

Local biological diversity, also known as alpha diversity, has three different components: the number of species in a given area (taxonomic diversity), the number of distinct traits that these species have (functional diversity) and their evolutionary distinctiveness (phylogenetic diversity). The relationships among these components of diversity vary across geography reflecting the differences in eco-evolutionary processes among distant regions.

(Above) 3D visualization of the empirical relationships between functional diversity, phylogenetic diversity and taxonomic diversity for amphibians in the Continental Americas based on our theoretical framework.

This study was motivated by the fact that different components of biological diversity have been shown to vary slightly in their geographical distribution: while species richness, phylogenetic diversity and functional diversity are broadly correlated, there are some regions where one measure of diversity is higher or lower than expected based on the others.

FROM THE COVER: Ochoa-Ochoa, LM, Mejía-Domínguez, NR, Velasco, JA, Dimitrov, D, Marske, KA. Dimensions of amphibian alpha diversity in the New World. J Biogeogr. 2020; 47: 2293– 2302. https://doi.org/10.1111/jbi.13948

We discussed extensively the possibilities to integrate these three dimensions of biological diversity in a single framework and developed a set of hypotheses about the potential drivers of variability in the relationships among the diversities.  We then mapped the spatial distribution of these diversity measurements and use our theoretical framework to explore the processes that may have generated the spatial patterns of amphibian diversity in the New World as we know it today.

Quilticohyla zoque is a treefrog species from the family Hylidae
from Nahá reserve, Chiapas, Mexico. Photo: LMMO.

We found that although the three aspects of diversity showed similar patterns, the geographical variation in the relationship between diversities suggested that a variety of processes, including ecological opportunity, habitat filtering, competitive interactions, among others have had different impacts on the different components of diversity. We also found regional differences dominant processes shaping diversity patterns.

Finally, we concluded that neither dimension of amphibian alpha diversity is a general predictor for other dimensions. Thus a single explanation about ecological and evolutionary processes underlying geographical variation in amphibian diversity is not possible. Our findings have major implications for conservation because setting conservation priorities may require analyses to determine which is the most important dimension of diversity to be conserved. Thus, the question of whether to give priority to history (e.g., antique lineages, evolutionary uniqueness), to high functional diversity (with rare or unique functions) or to taxonomic diversity (number of species) is critical.

Rhinophrynus dorsalis, is a Mexican burrowing toad from the family Rhinophrynidae
from Nahá reserve, Chiapas, Mexico. Photo: LMMO.

Ideally, if we want to preserve a wider range of the evolutionary spectrum, the aim should be, not only to conserve as many species as possible, but also to conserve a broad selection of different phylogenetic lineages and life history traits (functions). We expect that our findings will stimulate a new generation of local studies aimed at deciphering how diversity in ecological roles, evolutionary heritage and species numbers was assembled by ecological and evolutionary processes at finer spatial scales.

Written by:
Leticia Margarita Ochoa-Ochoa, Full Professor, Evolutionary Biology Department, Museum of Zoology, Faculty of Sciences, UNAM.
Nancy R. Mejía-Domínguez, Associated Researcher, Unidad de Bioinformática, Bioestadística y Biología Computacional, Red de Apoyo a la Investigación (RAI). Coordinación de la Investigación Científica, UNAM.
Julian A. Velasco, Associated Researcher, Centro de Ciencias de la Atmósfera, UNAM.
Dimitar Dimitrov, Associate Professor, Department of Natural History, University Museum of Bergen, University of Bergen, Bergen, Norway.
Katharine A. Marske, Assistant Professor, Geographical Ecology Group, Department of Biology, University of Oklahoma, Norman, Oklahoma, USA

For more information:
@Lety_OchoaOchoa /  http://academicos.fciencias.unam.mx/leticiaochoa/
@MejiaDNancy / https://sites.google.com/view/biostatisticsrai-unam/
@juvelas / https://www.atmosfera.unam.mx/ciencias-atmosfericas/cambio-climatico-y-radiacion-solar/julian-a-velasco-vinasco/
@spidersphylo / http://www.dimitardimitrov.name
@kamarske / Kamarske.org

JBI Annual Report on Equity, Diversity, and Inclusion

An increased awareness of systemic bias in institutions requires that we all examine the practices in which we participate. Around the turn of 2020, the Journal of Biogeography (JBI) began considering initiatives to promote opportunities for researchers currently underrepresented in biogeography, a discussion that continued throughout the year, and will go on for some time yet. A key part of this discussion is transparency in the current state of imbalance, inequity, and exclusion and changes in their status through time to hold ourselves accountable and ensure we are making progress. By way of this post, we begin this process of transparency and accountability, with JBI‘s first Annual Report on Equity, Diversity, and Inclusion.

Approach & results for 2020: There are many dimensions to diversity, and currently we are able to access information on only a subset of these, with some degree of accuracy, for a subset of roles within the publishing ecosystem. These data come from recent investments by Wiley to understand aspects of gender diversity of authors (currently, absent instruments for self-identification, we are restricted to estimates of binary gender diversity afforded by tools that assign female-male gender on the basis of statistical associations between first names and countries), from our abilities to retrieve geographic diversity in author submissions and publications in ScholarOne and the analytics behind this blog, as well as from a small number of public documents on the journal website and a diversity questionnaire completed by authors of blog posts. As a result, we report on aspects currently accessible and commit to improving our information systems in the coming years.

Editorial Board:

Associate Editors:
Current board composition: 15 women, 42 men.
New members added in 2020: 3 women, 2 men.
Total new invitations in 2020: 8 women, 4 men.
Geographic diversity by institutional location: 25 countries (Argentina 1, Australia 4, Austria 2, Belgium 2, Brazil 2, Chile 1, China 3, Cyprus 1, Denmark 1, Finland 2, France 2, Germany 2, Greece 1, Italy 1, Japan 1, Mexico 2, Netherlands 4, New Zealand 1, Northern Ireland 1, Norway 1, Poland 1, South Africa 4, Spain 2, UK 5, USA 9)

Deputy Editors-in-Chief:
Current board composition: 2 women, 3 men.
New members added in 2020: 1 man.
Geographic diversity by institutional location: 5 countries (France, Germany, Portugal, UK, USA)

Current board composition: 1, man.
Geographic diversity by institutional location: USA

Social Media Editors:
WeChat: 1, man.
Blog, Facebook, Instagram, Twitter: 1 woman, 1 man.
Geographic diversity by institutional location: 3 countries (Australia, China, Switzerland)
Cultural/national identity: American, Chinese, Chinese-European.

Editorial Academy:  
Current board composition: 3 women, 3 men.
New members added in 2020: 3 women, 3 men.
Total new invitations in 2020: 3 women, 3 men.
Geographic diversity by institutional location: 4 countries (Finland, Germany 2, UK 2, USA)
Cultural/national identity: China, Germany, Portugal (2), New Zealand, United Kingdom.


22% women


Gender diversity:

Submitting first authors: 27% women
Submitting corresponding authors: 26% women
Submitting authors: 25% women

Published first authors: 28% women
Published corresponding authors: 24% women
Published authors: 26% women

Geographic diversity:

(Above) The geographic sources, by lead author institute, of papers published in JBI

between September 2019-2020 (v.46 issues 9-12 and v.47 issues 1-9).


In 2020, JBI introduced three initiatives to advance principles consistent with the journal’s Equity, Diversity & Inclusion statement (see “Other” below).

Editorial Academy:
See above.

Small Grants for Global Colloquia in Biogeography:
In progress (to be reported in 2021).

JBI Awards for Innovation:
In progress (to be reported in 2021).


Early Career Researcher features (as of 18 Oct 2020):
10 women, 10 men
4 PhD, 15 postdoc, 1 other [postdoc equivalent]

153 countries (United States, Brazil, Germany, United Kingdom, India, Australia, Canada, Spain, France, China, Mexico, Netherlands, Italy, Switzerland, New Zealand, Sweden, Norway, Colombia, Japan, South Africa, Portugal, Chile, Austria, Argentina, Denmark, Belgium, Finland, Taiwan, Singapore, South Korea, Poland, Israel, Czech Republic, Nepal, Ireland, Hong Kong SAR China, Greece, Turkey, Peru, Pakistan, Indonesia, Ecuador, Thailand, Costa Rica, Philippines, Romania, Croatia, Nigeria, Russia, Malaysia, Bangladesh, Hungary, Estonia, Saudi Arabia, Benin, Kenya, Uruguay, European Union, Slovenia, Lebanon, Sri Lanka, Guatemala, Venezuela, Algeria, Slovakia, Iceland, Cyprus, Serbia, Egypt, Ghana, Morocco, Panama, Vietnam, Papua New Guinea, Lithuania, Bolivia, Cuba, Bulgaria, Kazakhstan, New Caledonia, Luxembourg, Puerto Rico, Ukraine, Uganda, Mozambique, Paraguay, Sudan, United Arab Emirates, Tanzania, Faroe Islands, Congo – Kinshasa, Gambia, Réunion, Oman, Honduras, Montenegro, Kuwait, Latvia, Bosnia & Herzegovina, Qatar, Namibia, Zimbabwe, American Samoa, Cambodia, Macau SAR China, Myanmar, Tunisia, Côte d’Ivoire, Albania, Madagascar, Zambia, Malta, Iraq, Palestinian Territories, Congo – Brazzaville, Burkina Faso, Burundi, Rwanda, Uzbekistan, El Salvador, Dominican Republic, Nicaragua, Jordan, Mongolia, Curaçao, Belarus, Ethiopia, Syria, Seychelles, Cameroon, Guyana, Monaco, Botswana, Barbados, Azerbaijan, Macedonia, Jamaica, Moldova, Afghanistan, Laos, Martinique, Armenia, Togo, Libya, Bhutan, Bermuda, Senegal, Angola, French Polynesia, Brunei, Maldives, Guam, Equatorial Guinea).

(Left) Number of page views of the JBI blog by country since inception, early January 2020.
(Right) Number of page views of the blog by country for the month ending 18 October 2020 shows potential for individual blog posts to reach audiences in usually underrepresented countries, in this case Nepal.


Like other journals, including Oikos, we consider diversifying biogeography to be integral with the future of biogeography, so JBI adopted Equity, Diversity & Inclusion statements at the beginning of July 2020. The statements can be found here and here (Section 5, bottom) and are designed specifically to address the need for inclusion to start with the earliest planning stages of research. A version of this statement also is included in JBI‘s initiatives (see above) that are explicitly intended to promote gender and geographic diversity among early career biogeographers.

Wiley is a signatory of the Joint Commitment for Action on Inclusion and Diversity in Publishing. link

Action items for 2021:

Growing from these initial data and experiences over the past year, we identify several goals on which we aim to work in the coming year. We do not consider this a complete list, nor a list of all that needs to be done. Goals for 2021 include:

To partner with other journals and societies on this matter, particularly sponsoring a discussion / session at an upcoming meeting.  Two ideas in this regard are:
– “Women in biogeography”
– “Island biogeography from the perspective of indigenous islanders”  

To increase geographic diversity among all of the journal’s constituencies: authors, editors, readers, reviewers.*

To increase gender diversity in leadership positions while being sensitive to workload.

To achieve gender parity and geographic representation in initiatives.

To increase gender diversity of authors, which in biogeography lags other ‘ecology’ titles (see figure below).

To begin a series of special or virtual issues focusing on diversity in biogeography. The first contribution will be 1 of ≥2 virtual issues on “Women in Biogeography” which we hope to publish later this year.

To implement a framework for better assessing diversity in submission and publication, such as improved analytics of manuscript metadata and post-decision information gathering from all authors.

Likewise, to implement a framework for assessing diversity in invitations to review cf. acceptances and submissions of reviews (see partial data in figure below).

To be responsive to Wiley’s recently formed DE&I advisory board which is creating a framework that could be applied to numerous journals across disciplines. 

*In the current report, geographic location of current institution is used as one dimension of geographic diversity in biogeography for which data currently are accessible. Action items for 2021 (above) include developing infrastructure for understanding ethnicity, nationality, cultural identify, country of origin.

(Above) Proportion of women in various roles in JBI relative to other Wiley ecology journals, 2019. While there is no substantial bias in acceptance rates (middle) relative to submission rates (top) at JBI, the journal has a lower proportion of female authors and reviewers than is average across ecology journals in general.

05 November 2020

ECR feature: Raquel Ponti de la Iglesia on shifts in migratory bird behaviour

Raquel is a postdoc at the Museo Nacional de Ciencias Naturales, Spain. She is a biogeographer and macroecologist with an interest in migratory birds. Raquel shares her recent work on historical shifts in the migratory behaviour of bird species that undergo Euro-African migrations.

Personal links. Twitter | ResearchGate

Institute. Museo Nacional de Ciencias Naturales (CSIC)

Academic life stage. Postdoc.

Major research themes. Macroecology, birds, biogeography, migration, islands.

Current study system. I am interested in all groups of birds. During my PhD, I studied birds that migrate from Africa to Eurasia. The fascinating thing about them is that they not only perform journeys of thousands of kilometres but also face extreme conditions during their journey (like crossing the Sahara desert). There is a great diversity of migratory Euro-African species, making them ideal to understand general behavioural patterns in birds. Currently, I am broadening my interests towards island biogeography and diversification in birds.

Recent paper in JBI. Ponti, R, Arcones, A, Ferrer, X, Vieites, DR. Lack of evidence of a Pleistocene migratory switch in current bird long‐distance migrants between Eurasia and Africa. Journal of Biogeography. 2020; 47: 1564– 1573. https://onlinelibrary.wiley.com/share/author/DQGGVVFKZP2YAKYZKUJG?target=10.1111/jbi.13834

Motivation for this paper. Current and past climatic changes have shaped bird distributions and migratory behaviours. Migratory behaviour can shift to sedentary behaviour relatively quickly during the evolutionary history of birds. In this context, some hypotheses suggest that North American birds stopped migrating during glaciations, remaining sedentary in their wintering grounds, and regaining their migratory behaviour in warmer periods. We wanted to test this hypothesis for Euro-African migratory birds, as the geography of both continents are different from the Americas.

A White stork (Ciconia ciconia)during thebreeding season in Lombardia (Italy). Photo: Marco Sannolo

Key methodologies. In this study, we used species distribution models to infer present and past breeding and wintering distribution of every Euro-African migratory bird species. We created maps of probability of occurrence for the present and the Last Glacial Maximum based on the climate that species currently experience in their breeding and wintering distributions. If we know which climatic conditions birds face in the present, we can infer where in Europe or Africa these conditions might have occurred in the past. We evaluated the differences between present and past distributions and measured the distances between both breeding and wintering ranges. We predicted that breeding and wintering distributions would overlap if there had been a change in migratory behaviour to sedentary status during glaciation events. We also reviewed the bird fossil record from the Plio-Pleistocene covering Europe and Africa. This provided us an independent corroboration of our models.

Major results. We found that bird migratory species did not stop migrating during the glacial periods of the Pleistocene. Euro-African migratory birds reduced their migratory distances, as part of the north Hemisphere were covered by ice. However, unlike American migratory birds, Euro-African birds continued migrating, remaining in the Mediterranean basin during the breeding season and crossing the Sahara belt until their wintering areas. This finding indicates that the geography of the continents may play an important role in the evolution of migratory behaviour, and that current migratory routes probably were established during the Pleistocene or before (at least the Eurasian-African flyways).

An Egyptian vulture (Neophron percnopterus) during the breeding in August in the “Hoces del Duratón” Natural Park in Segovia (Spain). Photo: Marco Sannolo

Challenges of this research. Making conclusions with climatic based modelling is challenging because the models offer us a view of how species could distribute if they followed the same climatic conditions as in the present time. However, we cannot be sure how conditions were in the past nor how species were distributed. Therefore, to study historical processes we had to make assumptions and provide a plausible explanation considering the reduced evidence of fossils. In our case, we chose to create a climatic envelop considering only the climate of the months of the breeding and wintering season, but we did not know how long breeding and wintering seasons were in the past. Hence, we created plausible average breeding and wintering seasons for all species, assuming that this season would not substantially differ from the actual ones.

Next steps. This study opens further questions about the lability of migratory behaviour under climatic changes. Given the current climate change scenario, we wonder how birds will respond to an increase of temperatures or intermittent droughts. We are interested in determining if migratory birds will change their migratory behaviour and increase their migratory distance. Furthermore, we also want to study the effect of global change in migratory arctic-bird distributions, such as shorebirds, which breed in very high latitudes and could not further change their breeding distributions to northern areas. The first step to answer these questions could be modelling bird distributions under possible global change scenarios and evaluating the distributional changes compared with the present.

If you could study any organism on Earth, what would it be? I would love to expand my research towards endemic birds from islands and their evolution and adaptation to new environments. In one of my studies, I found that almost all migratory species and subspecies that colonize an island remain sedentary and greatly change their morphological features. This opened me a new world that I would like to develop in the future. Although I mostly study bird species, I am also interested in other groups, like reptiles. If I had the opportunity to develop new research focused on biogeography and macroecology I would not say no to include other groups!

Journal of Biogeography Innovation (JBI) Awards

The Journal of Biogeography is pleased to announce the third of three new opportunities for Early Career Researchers: the Journal of Biogeography Innovation Awards.

The Journal of Biogeography invites submissions of manuscript proposals (brief outlines of manuscripts yet to be prepared) by Early Career Researchers for consideration for publication and awards for innovation.  

Proposals will be considered in three categories of article:
     – Perspectives and Syntheses
     – Original research
     – Methods

(For more information, see https://onlinelibrary.wiley.com/page/journal/13652699/homepage/forauthors.html)

Proposals on any subject in biogeography are welcome.  We particularly encourage studies in the following areas: Biodiversity–geodiversity; Comparative phylogeography and geo-genomics; Functional biogeography; Cross-scale biogeography & biodiversity (considering biological, spatial, and/or temporal hierarchies); Marine-terrestrial comparisons and contrasts (also with aerial, freshwater, and subterranean realms); Biogeography in the Anthropocene; New technologies; Interdisciplinary biogeography.

Proposals should be composed of the following and submitted as a single PDF:
     – Title
     – Targeted article type (see above)
     – ≤600 word proposal organized under the following headings:
          .. The gap in knowledge/understanding to be addressed 
          .. The context (incl. a brief review of the relevant literature)
          .. Goal or expected outcomes 
          .. Significance
     – List of authors (indicate the eligible ECR, who must be lead and corresponding author)
     – Contact information for the eligible ECR
     – Date the eligible ECR’s degree was conferred

Early Career Researchers are graduate students and postdocs (and equivalent positions) up to 5-years post award of the PhD (exclusive of career breaks). 

All proposals will be reviewed by an ad hoc committee of JBI academy, associate and chief editors on the following criteria:

  1. Novelty / originality of the idea (30%)
  2. Accuracy of identified problem and context (30%)
  3. Significance / impact (20%)
  4. Quality of preparation (20%)

Up to a dozen proposals in each category will be invited for submission as full articles, which should be submitted within 3 months of receiving the invitation.

Full articles will enter the standard editorial and review procedure of the journal and will be assessed for receipt of the award on the following criteria:

  1. Novelty / originality of the idea
  2. Accuracy of identified problem and context 
  3. Significance / impact of findings
  4. Quality of preparation of the manuscript

Journal of Biogeography will publish all invited articles freely under “full access” (i.e. downloadable from the journal website for one year from the date of publication).  In addition, the lead ECR authors of the three papers ranked most highly by the editorial team will receive a monetary award of $750 each.  

Proposal submission: 13 November 2020
Invite full manuscripts: 04 December 2020
Manuscript submission: 01 March 2021

Upload *proposals* as a single PDF with the filename “LASTNAME_FIRSTNAME_ECRproposal.pdf” only to: https://www.dropbox.com/request/kcjoSxpDrzb569JF2B27 *upload only*

Address enquiries (Subject line: “Enquiry: ECR Innovation Award”) to the Editor-in-Chief at mdawson@ucmerced.edu

JBI aims to foster inclusive science that reflects the disciplinary, human, and geographic diversity of biogeography and biogeographers. Submissions are welcomed from applicants of all ethnicities, races, colors, religions, sexes, sexual orientations, gender identities, national origins, disabilities, ages, or other individual status.

The mystery of ‘low gear’ locomotion

Mouse-goats, ‘demons of the forest’, and other insular bovids have short and robust limbs. Why?  The ‘low gear’ hypothesis had never been tested until we decided to fill this gap with a quantitative investigation of the causal forces influencing the acquisition of this peculiar type of locomotion.

Above: Skulls of a tamaraw (Bubalus mindorensis), a dwarf buffalo endemic to Mindoro island, highlighting different stages of ontogenetic development (Mammal Collection; Field Museum of Natural History, Chicago).

The Dutch palaeontologist P. Y. Sondaar already noticed in the 1970s that many insular ruminants, and to a lesser degree insular elephants and hippopotamuses, exhibited short and robust limbs. He explained this as an adaptation for a peculiar type of gait, that he described and named ‘low gear’ locomotion. Sondaar and other researchers after him mentioned several examples, including the iconic Balearian mouse-goat (Myotragus balearicus). They believed that this stout structure of the limbs would be advantageous, in the absence of predators, for low-speed walking in mountainous environments.

Bovids are intriguing elements of insular faunas and encompass phyletic dwarfs that occurred or are still living on islands located in different regions, from Southeast Asia to the Mediterranean. I have previously investigated their body size evolution on islands, (https://onlinelibrary.wiley.com/doi/full/10.1111/jbi.13197) and we decided to concentrate on the bovid family again in this study. Some of the best-known cases of ‘low gear’ locomotion include the already mentioned Myotragus as well as the tamaraw, a living dwarf buffalo endemic to Mindoro in the Philippines. We focused on the two main morphological traits associated with this peculiar type of gait, that is short and robust metapodials, and we calculated response variables in 21 extinct and living insular bovids. We assembled data on their life history and ecology and on the physiography of 11 islands. We estimated 10 predictors, including 4 topographic indices, and assessed their contextual importance by combining statistical and machine learning methods.

FROM THE COVER: Rozzi, R, Varela, S, Bover, P, Martin, JM. Causal explanations for the evolution of ‘low gear’ locomotion in insular ruminants. J Biogeogr. 2020; 47: 2274– 2285. https://doi.org/10.1111/jbi.13942

We demonstrated that the evolution of ‘low gear’ locomotion in insular ruminants does not result simply from phyletic dwarfing and from the absence or scantiness of predators in the focal communities. Instead, we showed that release from competitors on species-poor islands plays an essential role in prompting adaptations for this peculiar type of gait. While island topography is not as relevant as interspecific dynamics in influencing the evolution of the focal morphological traits, the amount of mountainous terrain occurring on each island seems to significantly affect the evolution of robust metapodials in insular bovids. All in all, our study supports the idea that the evolution of ‘low gear’ locomotion would be the product of a complex interplay of biotic and abiotic factors, and calls for caution in drawing conclusions on this phenomenon on the basis of single, albeit significant cases.

(Left) Roberto measuring a skull of the iconic mouse-goat, Myotragus balearicus, at IMEDEA – Mediterranean Institute for Advanced Studies, Mallorca. M. balearicus was an endemic caprine that lived on Mallorca and Menorca during the Late Pleistocene and Holocene, before becoming extinct following the arrival of humans around 4300 years ago. (Right) Roberto embraced by the horns of a river buffalo, Bubalus bubalis, in the mammal collections at the Smithsonian National Museum of Natural History, Washington DC.

An unexpected outcome of this study was to find out that, even though the most extreme cases of ‘low gear’ locomotion occurred on islands with no mammalian predators, our models did not show a significant relationship with this predictor. To sum up, the a priori hypothesis that this low-speed gait would simply result from predator release on islands needed to be reconsidered. Discussing the role of ecological and topographic traits in influencing the evolution of ‘low gear’ locomotion was challenging, because of their complex interaction and the variation in morphological responses to those factors within insular bovids. In fact, we observed a variety of trait combinations, with species exhibiting different degrees of robustness and shortening of metapodials, and different responses to many of the focal predictors by species belonging to one or the other subfamily of bovids in the study.  Thus, much effort is still needed to verify how robust island syndromes are and to understand their causation. In this vein, I am planning to continue to explore other peculiar traits exhibited by these fascinating animals. In particular, I am looking forward to implementing advanced methodologies in palaeoneurology to investigate patterns of brain size variation and changes in the degree of cortical folding in insular Artiodactyla.

More broadly, my research focuses on the evolution and extinction of mammals on islands. There is some urgency to this.  In response to the special characteristics of island environments, these animals often undergo fascinating evolutionary changes, including changes in body size and in the morphology of their skull, brain, teeth and limbs. My collaborators and I are currently focusing on how the evolutionary changes undergone by insular mammals predispose them to heightened extinction risk. I am investigating the relationship between their peculiarity and their fragility, as many of these evolutionary marvels are often threatened or already extinct. In collaboration with other palaeontologists, mammalogists and biogeographers, we are integrating data on fossil and living insular mammals to document their extinctions across large scales of time and to inform conservation strategies.

Mounted skeleton of the extinct (Middle Pleistocene) Sicilian dwarf elephant
Palaeoloxodon falconeri at Museo Geologico ‘G. G. Gemmellaro’, Palermo, Sicily.

The application of theories and analytical tools of palaeontology to provide valuable information for conservation planning is one of the key drivers of my research. Many threatened island mammals receive scarce conservation action because they are deemed ‘uncharismatic’ and fail to attract funding. Palaeontological studies have the potential to produce detailed information on the evolutionary history and uniqueness of these species and, thus, draw attention to their conservation value. I did my PhD on insular bovids and I was saddened to read that, in a recent study on the full collection of mammals from the Prague Zoo, the lowland anoa (Bubalus depressicornis) was ranked as one of the least attractive species. Sometimes referred to locally as Sulawesi’s ‘demon of the forest’, anoas never cease to inspire my research and, as a member of the IUCN SSC Asian Wild Cattle Specialist Group (https://www.asianwildcattle.org/), I feel it is important to keep highlighting how beautiful and unique these dwarf buffaloes really are.

The evolutionary anomalies of island life are among the most spectacular phenomena in nature, yet islands contain a disproportionately higher amount of threatened and extinct biota compared to continents. I have always found the ecologically naive and fragile nature of these taxa extremely intriguing. Dwarf elephants and hippos, giant rats and shrew-like insectivores larger than a cat, short-legged bovids with stereoscopic vision, deer with bizarre antlers, etc. Both the fossil record and islands today are home to mesmerizing mammal species.

Written by:

Roberto Rozzi

Postdoc, German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig

For more information: https://twitter.com/Rozzi_Roberto | https://scholar.google.it/citations?user=ZTz5g0QAAAAJ&hl=en


(Left) View of Monte Tuttavista, one of the major Sardinian localities yielding Quaternary fossil vertebrates ranging in age from the Early to Late Pleistocene. Bovids of the so-called ‘Nesogoral group’ were also recovered from this site and included in our study. (Centre) Roberto Rozzi at Gásadalur, Vágar, Faroe Islands.
(Right) Crystal clear waters of Caló den Rafelino, Mallorca, where remains of the earliest representative of the Myotragus lineage were found (Myotragus palomboi; Early Pliocene).

ECR feature: Jonathan Sandoval-Castillo on guitarfish speciation

Jonathan Sandoval-Castillo is a postdoc at Flinders University. He is a phylogeographer that integrates molecular and ecological data to study the evolution of elasmobranchs. Jonathan shares his recent work on the cryptic lineages and speciation of guitarfish.

Jonathan sampling elasmobranch tissue from artisanal fisheries. Jonathan visited over 30 artisanal fishery camps around the Gulf of California and the Baja California Peninsula during his PhD fieldwork.

Personal links. Twitter | ResearchGate | Google Scholar | Lab web page

Institute. Flinders University

Academic life stage. Postdoc

Major research themes. I am attracted to the biogeography, phylogeny, and evolution of marine organisms, especially the speciation process in elasmobranchs (sharks and rays). I am interested in the integration of molecular and ecological approaches to elucidate evolutionary histories in aquatic ecosystems.

I study guitarfish. These fish show an intermediate body shape between sharks and rays, and are a diverse group of elasmobranchs with several species living in sympatry. They are highly abundant and, being predators, they are an important component of coastal benthic ecosystems. In addition, some species have high value meat and are the main component of several artisanal fisheries in developing countries. However, guitarfish are also one of the vertebrate groups most vulnerable to overexploitation. Two main factors constrain their effective management and conservation: a lack of basic biological information and numerous difficulties surrounding proper identification of the species.

Current study system. I study guitarfish. These fish show an intermediate body shape between sharks and rays, and are a diverse group of elasmobranchs with several species living in sympatry. They are highly abundant and, being predators, they are an important component of coastal benthic ecosystems. In addition, some species have high value meat and are the main component of several artisanal fisheries in developing countries. However, guitarfish are also one of the vertebrate groups most vulnerable to overexploitation. Two main factors constrain their effective management and conservation: a lack of basic biological information and numerous difficulties surrounding proper identification of the species.

Recent paper in JBI. Sandoval-Castillo J, Beheregaray LB (2020) Oceanographic heterogeneity influences an ecological radiation in elasmobranchs. Journal of Biogeography 47:1599–1611. https://rdcu.be/b4fuY

Motivation for this paper. Speciation is one of the most important and least understood processes in nature. Most biologists agree that species are fundamental biological units for several ecological and evolutionary processes. However, contention still exists about the definition, delimitation, and origin of species. This challenges the study of processes and mechanisms that create and maintain biodiversity. This is especially true for elasmobranchs. Despite elasmobranchs being a charismatic and highly diverse group of vertebrates, they are underrepresented in the scientific literature and very little has been done to decipher the main mechanisms by which new species of sharks and rays originate. However, because of elasmobranchs’ relatively moderate to high mobility, we expect that ecological isolation plays a major role in their diversification. To test this hypothesis, we selected the guitarfish from the Gulf of California because the group has high diversity in the area. In addition, the Gulf of California has both an active geological history and high oceanographic variability, enabling us to test the relative effect of vicariance events and ecological isolation on diversification of the marine populations inhabiting the region.

A Pseudobatos guitarfish.

Key methodologies. We assessed the role of oceanographic variation in the diversification of guitarfishes (genus Pseudobatos) in the Gulf of California by integrating genetic and environmental datasets. We first used the genetic data (mtDNA sequences and AFLP genotypes) to determine the number of guitarfish lineages present in the Gulf of California and elucidate their phylogenetic relationships. We then combined distribution models and seascape genetic analyses to establish the relative importance of six oceanographic variables that might have affected genetic differentiation between lineages. Finally, we used coalescence models to separate the role of historical geological events from the role of modern oceanographic variation on the diversification of these lineages.

Major results. Our work evidences five distinct lineages of Pseudobatos, with geographic distributions overlapping ecologically discrete bioregions in the studied area. Moreover, genetic differences between lineages are correlated with sharp dissolved oxygen and nutrient concentration gradients between these bioregions. We propose that the bioregions present heterogenous habitat opportunities and a source of divergent selective pressures. These promote metabolic specializations associated with differences in oxygen concentration and diet that together triggered a recent adaptive radiation of Pseudobatos. Our work showcases the role of isolation by environment in generating and maintaining diversity in this group and suggests that mobility might not hinder speciation in sharks and rays. Our study likely represents the first assessment of a recent ecological radiation in elasmobranchs. It also offers a new perspective about the application of integrative approaches to study the effect of divergent selection on biological diversification in the ocean.

The Gulf of California is an excellent system to study biogeography: it has an recent active geological history and high temporal and geographic oceanographic variability (Photos: Israel Sanchez Alcantara).

Unexpected results. We found five distinct lineages of Pseudobatos in the Gulf of California and the Baja California Pacific Coast, including four cryptic lineages. At first, we thought this large number of lineages was a mistake since the 210 samples were identified as just two described species. However, we re-sequenced several samples that validated the presence of these apparently cryptic lineages. Moreover, using museum specimens, Kelsi Rutledge from the University of California recently described subtle but significant morphological differences that discriminate at least two of these lineages, corroborating some of our results and highlighting the need for more exhaustive taxonomic work in the region.

Next steps. I would like to do several genomic analyses on the samples. First, to study the genes involved in this ecological radiation, and second, to perform demographic analysis on a more recent temporal scale and explore the effects of past and current climatic changes. This will help to determine more specific biological and oceanographic factors that promote rapid speciation in these organisms, and in the ocean in general.

If you could study any organism on Earth, what would it be? I would study deep water sharks from the family Etmopteridae, because they are very diverse, can produce bioluminescence, and are poorly studied. There are ~45 species recognized, of which several are considered to have broad geographic distributions, but most likely represent complexes of cryptic species. Some of these complexes would be ideal for studying the speciation process in different stages. The Etmopteridae sharks show several adaptations to deepwater habitats, including bioluminescence. Understanding the evolution of the biochemistry and physiology of these adaptations could be the first step to produce bioluminescence in an ecologically sustainable way. Unfortunately, they are recognized as a group highly susceptible to over-exploitation and human derived climatic change. However, due to the relative inaccessibility of their environment, and the logistical difficulties linked to their maintenance in laboratory, Etmopteridae sharks are poorly studied in general.

ECR feature: Amazonian trees with Vitor Gomes

Vitor H. F. Gomes is a postdoc affiliated with the Federal University of Pará, Instituto Tecnológico Vale, and Centro Universitário do Pará. Vitor studies the response of Amazonian tree species to global change, and is particularly interested in the effects of climate change and deforestation on species diversity and distribution. His recent work investigates the diversity and distribution of all known Amazonian tree species — 10,071 in total.

Vitor in Mocambo Forest – Pará Brazil 2017: monitoring and measuring a 60 year old permanent plot in Amazonia.

Links: Personal page | Twitter | Instagram

Institution: Federal University of Pará – UFPA, Instituto Tecnológico Vale – ITV, and Centro Universitário do Pará – CESUPA

Current academic life stage: Postdoc

Research interests: I am interested in understanding how Amazonian tree species respond to global change, focusing on the effects caused by climate change and deforestation on species diversity and distribution.

Current study system: I currently study the diversity and distribution of all known Amazonian tree species, a total of 10,071 according to the most recent list. Half of those species may be threatened with extinction by 2050, since they are continually impacted by global change, especially by deforestation and climate change. Amazonia is the largest single block of rainforest on the planet and holds roughly half of all tree species in tropical areas. Understanding the impacts of global change on Amazonian tree species diversity and distribution is fundamental to predict the future of rainforest under human-induced changes, also to maintain and safeguard Amazonian biodiversity.

(left) Vitor in the National Forest of Caxiuanã – Pará/ Brazil 2016: research trip in Amazonia monitoring 11 ha of permanent plots and collecting samples for DNA Barcoding of over 400 species. Speedboat displacement to the permanent monitoring plots, (right) National Forest of Caxiuanã – Pará/ Brazil 2017.

Recent paper in Journal of Biogeography: Gomes, V. H. F., Mayle, F. E., Gosling, W. D., Vieira, I. C., Salomão, R. P., & ter Steege, H. (2020). Modelling the distribution of Amazonian tree species in response to long‐term climate change during the Mid‐Late Holocene. Journal of Biogeography, 47(7): 1530-1540. https://doi.org/10.1111/jbi.13833

Motivation for the paper: Previously published pollen records of rainforest tree species extracted from lake sediments in the southern margin of Amazonia showed that eastern Bolivia rainforests expanded southward over Cerrado savannas between the Mid and Late Holocene (past 3000 years). The concentration of rainforest tree pollen increased in two lakes (sites), Laguna Bella Vista (northern) and Laguna Chaplin (southern), which are 100 km away from each other. The rainforest communities surrounding Laguna Chaplin are younger than those around Laguna Bella Vista, indicating that species have expanded their distribution southward between those lakes in very recent times. This expansion is attributed to the increased seasonal latitudinal migration of the Inter Tropical Convergence Zone. Based on that, we wondered if species’ climate-based environmental suitability also increased during the Mid-Late Holocene in Amazonia, especially in the southern part, contributing to the rainforest expansion. We also wanted to confirm how pollen records from the topmost sediments (surface) correlate to the relative abundance of current plant species. We can use this information in our future research to simulate the abundance distribution of tree species in the past based on fossil pollen data.

Key methodologies: We used models based on machine learning and inverse distance weighting interpolation to produce maps of environmental suitability and relative abundance for tree species of Moraceae and Urticaceae, based on natural history collections and a large plot dataset. We used environmental suitability to test the response of the Amazonian rainforest to long-term climate change. Then, we quantified the increase in suitable areas for tree species in the past 6,000 years. We also used species relative abundance maps to test the correlation between species abundance in the current vegetation versus modern pollen assemblages. Our methods demonstrate how Amazonian rainforest responds to long-term climate change, and addresses questions about tree species distribution under past climate conditions. Also, our methods clarify the relationship between pollen and plant species abundance, connecting evidence of past rainforests from pollen records to species abundance plot data in the present.

(left) Vitor in the National Forest of Saracá-Taquera – Pará/Brazil 2009: research trip in Amazonia monitoring a permanent plot close to the edge of a 200 meter plateau, (right) National Forest of Saracá-Taquera – Pará/Brazil 2009: research trip in Amazonia monitoring and measuring permanent plots on a reforested area. Rest time. Left to right: Mario Rosa (Goeldi Museum), Mr. Bieco (Coopertec), Nelson Rosa (Goeldi Museum), Vitor Gomes.

Unexpected challenges: We found that the suitable areas and species richness for the species studied were higher in a narrow band in the Guiana Shield. Despite that, the abundance of species was very low in this area. Our understanding was that other factors besides environmental conditions might drive species distribution, such as biotic interactions, dissociating potential species distribution from observed species distribution. This outcome may lead the way to new questions and propositions regarding contrasting north-south patterns between species abundance (lower-north/higher-south) and environmental suitability (higher-north/lower-south). Perhaps we can expect lower plant abundance in areas with higher environmental suitability, since competition between species increases with optimal environmental conditions.

Mocambo Forest – Pará Brazil 2017: Research trip in Amazonia monitoring and measuring a 60 year old permanent plot. Collecting leaves. Vitor Gomes and Nelson Rosa (Goeldi Museum).

Major result and contribution to the field: We found that the mean environmental suitability of Moraceae and Urticaceae increased over the past 6,000 years, with southern ecotonal Amazonia showing the highest increase. The accompanied modelled mean species richness increased by as much as 120% throughout Amazonia. However, we found that under a future warmer and drier Amazonia, it is likely that the Holocene range expansion will be reversed over the 21st century. We predict that increased moisture stress will lead to forest and diversity losses, especially in ecotonal areas of Amazonia. Furthermore, we found that the current mean relative abundance of Moraceae and Urticaceae correlated significantly with the modern pollen assemblages for these families. This correlation implies that pollen records can be used to reconstruct the relative abundance of the species in the past.

What are the next steps? The crossover between pollen records, abundance data and environmental suitability models looks promising. The first step is modelling all Amazonian tree species distributions in the past, and looking deeper into the past, reaching the Last Glacial Maximum (~21 kyr before present) and the Last Interglacial (~100 ky before present). Second, I’ll expand our pollen analysis to all tree species with available records. These analyses may connect many pieces of the Amazonian rainforest history. I’m starting a postdoc focusing on the future of Amazonia based on the Paris Agreement goals, which aim to understand how past changes may help us to figure out the possible outcomes of current and future human-induced changes.

If you could study any organism on Earth, what would it be and why?
I would like to understand the relationship between tree species and their pollinators and dispersers. That would help to understand processes related to tree species distribution. Bees would be a good start, since many tree species in Amazonia are pollinated by them, and bees are as threatened as tree species due to human-induced changes.

Any other little gems you would like to share? Researching is pretty far from easiness; it is about passion, which makes us surpass distance, cultural differences, economic crises, budget issues and many other challenges present in the daily life of researchers. I should say a big thanks to the coauthors Hans ter Steege, Willian Gosling, Frank Mayle, Ima Vieira and Rafael Salomão, who are all passionate about Amazonia and supported this project.

National Forest of Caxiuanã – Pará/ Brazil 2016: monitoring 11 ha of permanent plots and collecting samples for DNA Barcoding of over 400 species. Rest time and lunch. Left to right: Vitor Gomes, Arua ter Steege, Hans ter Steege (Naturalist), Mr. Joca (Ferreira Pena Station), Nelson Rosa (Museum Goeldi).

Introducing the Inaugural Editorial Academy

The new Editorial Academy at Journal of Biogeography is aimed to help early career biogeographers who are interested to learn more about the publishing process to gain experience with the guidance and support of an experienced mentor.

We are delighted to announce the six inaugural members — Drs. Ricardo Correia, Qin Li, Tom Matthews, Filipa Palmeirim, Amanda Taylor, and Alex Zizka — who begin their tenures today and who will be with the journal for the next two years, after which they may be appointed to the full editorial board.

These early career researchers span a diversity of disciplines, career stages and appointments, and beckon from six different countries. All share a deep interest in biogeography, to which they bring new skills and perspectives that will enrich our perspectives at the journal.

Each of the Editorial Academy members will be partnered one-to-one with a chief editor of the journal and will have the same role as a regular member of the Editorial Board, but a reduced load. The editorial academy brings considerable expertise and a new vantage point to the journal, and we all very much look forward to working together.

If this is an opportunity that may interest you in the future, watch out mid-2021 for the next opportunity to join the editorial academy and board at the Journal of Biogeography.


Ricardo A. CorreiaHelsinki Lab for Interdisciplinary Conservation Science (HELICS), University of Helsinki. Research interests: Species distributions in space and time for conservation applications; using novel data sources to understand how humans are shaping the natural world and using that knowledge to inform conservation.

Qin LiField Museum of Natural History, Chicago, USA. Research interests: Patterns of plant diversity, biogeography of species interactions, and processes of diversification in a changing environment. Especially, floristic structure & environmental, species assembly and co-existence, speciation and adaptation, and ecological niche dynamics in mountainous areas; comparative methods, genetics, and field studies.

Tom MatthewsUniversity of Birmingham, UK. Research interests: Assessing issues in global environmental change using macroecological, macroevolutionary and biogeographical approaches. Using a mixture of theoretical and empirical methods to investigate various macroecological topics, including species–area relationships and species abundance distributions; any place and taxon, but especially islands and birds.

Ana Filipa PalmeirimUniversity of East Anglia, UK. Research interests: Complex biodiversity responses to habitat loss and fragmentation, and how they affect foodweb structure and overall ecosystem functioning. Her research is focused on both terrestrial and insular forest fragments (reservoir islands) across tropical forests, combining different dimensions of diversity at multiple spatial scales.

Amanda TaylorUniversity of Göttingen, Germany. Research interests: Disentangling complex diversity patterns on islands using plants as model organisms. Particularly constraints on the assembly of island floras such as species interactions (e.g. plant-pollinator) or the environment (e.g. climate).

Alexander ZizkaGerman Centre for Integrative Biodiversity Research (iDiv). Research interests: Evolution and distribution of tropical plants (especially the pineapple family, Bromeliaceae), and the use of “big data” for biogeography and conservation. Integrating large-scale data sets of species distribution with molecular phylogenies and traits, to understand biodiversity in time and space.

ECR feature: Alpine treelines with Shalik R. Sigdel

Shalik is a postdoc at the Institute of Tibetan Plateau Research. He an ecologist working in the Himalayas to understand how climate change might cause shifts in alpine treelines. Shalik shares his recent work on the combined influence of climate and intraspecific interactions on these treelines.

Shalik collecting treeline data in the Manang valley, central Nepal. (Photo credit: Samresh Rai, 2 November 2015)

Personal links. Twitter | ResearchGate | Google Scholar

Institute. Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing China

Academic life stage. Postdoc.

Major research themes. My research focuses on understanding alpine treeline responses to changing climate at multiple spatial scales using dendroecological tools, particularly in the Himalayas. I have a keen interest in the use of spatio-temporal data for understanding how treeline responds to changing climate.

Current study system. Currently, I am working on the treeline ecotone in the central Himalayas. The Himalayas host one of the longest natural treeline ranges, extending from Pakistan to southeast China crossing different climatic zones (westerly- and monsoon-dominated areas). As this area is experiencing a faster warming rate than other areas, the alpine treeline is considered as a potential indicator to track influence of climate warming on alpine ecosystem. In response to climate warming, the treeline is expected to move upslope. However, our early study showed a non-linear relationship between rates of treeline shift and warming climate, raising some questions about the mechanisms affecting the treeline shift.

A natural Himalayan birch (Betula utilis) treeline located at ablout 4100 m. a.s.l. in the Langtang valley, central Nepal. (Photo credit: Shalik Ram Sigdel, 17 April 2014)

Recent publication in JBI. Sigdel, S. R., Liang, E., Wang, Y., Dawadi, B., Camarero, J. J. (2020). Tree-to-tree interactions slow down Himalayan treeline shifts as inferred from tree spatial patterns. Journal of Biogeography, 47(8):1816–1826. https://doi.org/10.1111/jbi.13840

Major motivation for this paper. The major motive of this research was to investigate the role of intra-species interactions (spatial patterns) on responsiveness of treelines to climate warming. Mountainous regions across the globe (including the Himalayas) have been experiencing increased recruitment as a result of climatic warming. However, in the Himalayas, the rate of treeline shift has been slower, relative to other parts of the world. Heterogeneous response of Himalayan treeline to a warming climate indicates that rates of treeline shifts may be affected by local-scale interactions (particularly intra-species interactions). However, it is unknown whether Himalayan treeline dynamics show lagged or weak responses to climate warming due to treeline densification and clustering intensity of trees (tree-to-tree-interactions) or not. We expected to discern if tree-to-tree-interactions regulate the pace of treeline shifts, and to determine if those interactions are more important drivers of changes at treelines than climate. We hope this study will help to better understand how local interactions drive large scale pattern formation at treeline and their response to changing climate.

Key methodologies. We established a network of treeline plots across the central Himalayas, encompassing a wide longitudinal gradient characterized by increasing precipitation eastwards. The location of each individual tree within the plot was measured, and their ages were estimated by applying a dendrochronological approach. We used the locations and age of the trees to calculate the changes in tree density, treeline elevation changes, distance between neighbouring trees, and the spatial patterns (clustering intensity) for 50-year age-classes (1-50, 51-100, 101-150 years) of two main tree species at the treeline (Himalayan birch and Himalayan fir). The relationships between these parameters were used to understand the driving mechanism of Himalayan treeline shift.

Taking tree-ring sample from Himalayan fir (Abies spectabilis) to get the germination date and age of the trees (Photo credit: Samresh Rai, 31 October 2015)

Major challenges. Our treeline sites were located in remote mountain region of the Himalayas and can be reached after 3-4 days continuous trekking. The Himalayan mountains are characterized by a complex regional climate system. Hostile climatic conditions and the remoteness of treeline sites are big challenges to surveying a large-scale network of treeline plots, which took several months. Even though we had only a very short time window suitable for conducting field surveys, we were able to collect data along the east-west precipitation gradient (more than 800 km) across the central Himalayas after 3 years continuous effort.

Major results. Based on the network of treeline plots across an east-west precipitation gradient in the central Himalayas, our study revealed that treeline shift rates were not only limited by climate but also affected by intra-species relationships. Higher clustering of young trees increased with increasing moisture stress from the eastern to western sites but treeline shifts rates were higher at wet eastern treelines where clustering intensity is lower than at dry western sites. The higher distance between neighboring trees, the faster the shifting rate, and vice-versa. This is an important empirical advance in the study of driving mechanism of alpine treeline shift, showing how climatic and non-climatic factors interact at the local scale to drive treeline patterns. Furthermore, it explains the spatial differences in treeline shifts from the perspective of intraspecific relationships, and quantifies the role of biological factors on treeline shifts. It also underscores the lag effect of treeline shifts in response to climate warming.  

Next steps? In this study, we considered the treeline sites dominated by single species (either Betula utilis or Abies spectabilis). But we found some treelines with both species together. Currently, we are working on such mixed species treelines to determine if species specific spatial patterns shape treeline structure and to examine if those patterns drive the shift rate of particular species.

If you could study any organism on Earth, what wold it be? I am fascinated by alpine grassland ecosystems, which are highly sensitive to global change. Alpine plants are the most interesting organisms to me and I would love to study the impact of climate change on their establishment, survival, reproduction and distribution, particularly in the central Himalayas (which is a global biodiversity hotspot). As one of the most affected terrestrial ecosystems, alpine plant communities in the Himalayas are ideal systems to monitor the impacts of climate warming. Additionally, I feel relaxed while working in the beautiful Himalayan mountains, and enjoy the pristine environment.

Marooned on the Houtman Abrolhos

Within a global biodiversity hotspot, one of the highest latitude true coral reefs in the world, the oldest European structure in Australia, a rich and colourful marine environment, perhaps the most infamous murderous mutiny in marine history, intensive human destruction of habitat and still little known to the most of the world, the Houtman Abrolhos archipelago provides a wonderful setting and a rich resource for biological study. The reptile fauna were once part of the mainland but have been isolated for the last 6 or 7 millennia, allowing us to predict likely changes of the same species in fragmented mainland habitats created over the last century.

This remote archipelago, 50 km off the coast of Western Australia, contains the oldest European structure in Australia: Wiebbe Hayes Fort. This stone structure was built in 1629 by marooned soldiers who survived the mutiny and massacre that followed the shipwreck of the Dutch vessel, Batavia. The soldiers were indeed fortunate to have fresh water, pooled in limestone solution holes, abundant wildlife and avoid the long, hot and dry summer.

Wiebbe Hayes Fort, constructed in 1629 on West Wallabi Island to protect soldiers from intermittent raids by mutineers from the shipwrecked Dutch merchant vessel, Batavia.

But human destruction on the Abrolhos has not been confined to our own species. During the late 19th century, a guano industry harvested phosphate rich soil, derived from internationally important seabird breeding populations, devastating the soil and vegetation of 16 islands. This was also the catalyst for introducing exotic biota. During the last 70 years, a thriving and lucrative western rock lobster industry developed with fishers’ huts built on 22 islands, and schools and airfields on three. This collage of environmental changes has modified the abundance and challenged the persistence of many species. In dramatic contrast is the sustainable environmental use by Aboriginal Australians that occupied the region for over 50000 years; although they were not resident on the Abrolhos at the time of European arrival.

FROM THE COVER: How, RA, Cowan, MA, Teale, RJ, Schmitt, LH. (2020) Environmental correlates of reptile variation on the Houtman Abrolhos archipelago, eastern Indian Ocean. J Biogeogr. 47: 1– 12. https://doi.org/10.1111/jbi.13881

Insular populations have long fascinated biologists. The faunas of the Galapagos and eastern Indonesian archipelagos led Charles Darwin and Alfred Wallace to their profound insights of fundamental evolutionary principles.

The Abrolhos is our most recent evolutionary palette. It comprises 170 islands that have been isolated from mainland Australia on several occasions during the periodic fluctuations in Pleistocene sea levels; the most recent isolation beginning around 6500 years ago. This disconnect provides the opportunity to examine short-term, fundamental evolutionary changes in biota on islands of different sizes and geomorphology, in three defined groups separated from one another and the mainland.

This study evolved from our multi-decadal research of insular populations in temperate and tropical Australia, and Wallacea. With our colleague Darrell Kitchener, we illustrated the significance of sea barriers to the evolution of mammalian and reptilian taxa across eastern Indonesian. Many fauna show differences between adjacent islands that remained separated throughout the past 2 million years. Others illustrated morphological and genetic divergence of adjacent islands separated for only the past few thousand years.

Our interest in the Abrolhos’ isolated populations was piqued by the recent studies of David Pearson and Zoe Hamilton on the iconic python and spiny-tailed skink that showed inter-island differences in morphology and genetics. The archipelago is also the ‘type’ locality for seven Australian reptile species, making the collection of tissue from these defining populations imperative to understanding the evolutionary relationships of taxa. Our program focused on determining the diversity of reptile assemblages and populations on islands that represented a range of sizes, geomorphologies, habitats and covered all three island groups. Another principal objective has been to compare morphological and genetic variation of island taxa to their mainland counterparts.

(1) Pigeon, Oystercatcher, Tattler and West Wallabi islands in the northern Houtman Abrolhos. (2) Spiny-tailed Skink on West Wallabi 2011. (3) Dwarf Bearded Dragon basking on East Wallabi, 2012. (4) The endemic Abrolhos Dwarf Bearded Dragon (Pogona minor minima) is found on only a few islands of the Houtman Abrolhos archipelago in the eastern Indian Ocean. The Abrolhos is best known for centuries-old Dutch shipwrecks and the location of the massacre of the Batavia survivors, however, it also has a diverse reptile assemblage whose species show marked morphological differences between islands. Photos by Ric How.

Decades of collaborative research with fellow West Australians allowed us to ‘keel-haul’ colleagues into providing their assistance on six field-trips – all for the princely sum of a week or so on a chartered vessel among one of Australia’s most fascinating and beautiful archipelagos! The Indian Ocean surrounding the Abrolhos greatly enhances the rich biodiversity. Small colonies of rare Australian Sea Lions ‘haul-out’ on shorelines of several islands, while turtles and spectacular coral reefs, the world’s southernmost, provide constant distractions during field programs.

The excitement of discovering a new species cannot be overstated but, despite over 100 years of opportunistic reptile collecting, we also documented many new populations on islands and three previously unrecorded species. Remarkably, most populations showed size differences between islands and we await with interest their imminent genetic appraisal. However, none of seven environmental correlates provided a consistent explanation for the observed inter-island differences in morphology. An exceptional behavioural observation was of a mating aggregation of pythons in a limestone solution cavern adjacent to Wiebbe Hayes Fort where a large receptive female was entwined by five attendant males, all with a singular intent. Modified by European occupancy the Abrolhos may be, but the reptile fauna remain steadfastly focused on fundamental evolutionary behavior!

Mating aggregation of Carpet Pythons in a limestone solution cavern on West Wallabi Island, adjacent to Wiebbe Hayes Fort.

Abrolhos reptile assemblages and their richness are significantly correlated with island area, geomorphology and native plant species richness. The proposed development of eco-tourism infrastructure on the Abrolhos requires consideration of conservation measures designed to protect this diversity of islands, assemblages and species. Reptiles isolated on Abrolhos islands also inform the extinction debt inherent in more recently isolated populations on the mainland, a consequence of agricultural and urban development over the past 100 years, and requiring active management for their persistence.

Written by:
Linc Schmitt1 & Ric How2
1 Emeritus Professor, School of Human Science, The University of Western Australia and Research Associate, Department of Terrestrial Zoology, Western Australian Museum
2 Adjunct Professor, School of Human Science, The University of Western Australia and Research Associate, Department of Terrestrial Zoology, Western Australian Museum

We would like to thank Roy Teale, Mark Cowan and Jason How who commented on this blog.