Global Assessment of Reptile Distributions
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Modelling IUCN threat status for global reptiles

1/5/2022

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PictureVallarta Mud Turtle (Kinosternon vogti), classified as ‘Critically Endangered’ by the automated assessment method and as not evaluated by the IUCN Red List of Threatened Species (Photo: Agencia Informativa Conacyt/ Wikimedia)
Reptiles comprise nearly 11,800 species worldwide, and are the most species-rich land-vertebrate group. After 18 years of laborious work by many experts globally, early in 2022, the first extinction risk assessment of this group was completed (the Global Reptile Assessment). This important endeavor will enable adding reptiles to global conservation policy and management initiatives as one of the major groups assessed. Nevertheless, this assessment still leaves over 3000 reptile species that have either not been assessed or were assigned a data deficient category that prevents their prioritization for conservation. In an effort to fill-in this gap a new publication in the journal PLOS Biology, we presents estimates of extinction risk for those species currently neglected by the Global Reptile Assessment, using novel machine learning modelling. importantly we found that unassessed and data deficient reptile species are more likely to threatened than assessed species.
Gabriel Caetano, lead author of the paper explained “The IUCN threat assessment procedure is highly important, yet very lengthy, data intensive, subject to human decision biases, and relies on in-person meetings of experts. However, we can use information on already assessed species to better understand the risks to those not yet assessed. Species may share physiological, geographic, and ecological attributes (often via shared evolutionary history) that make them more threatened, and experience similar sources of threat when they occur at similar locations. In our work we tried to emulate the IUCN process using predominantly remotely sensed data and advanced machine learning methods. We used species that have been assessed to teach our models what makes a species threatened and then predict the threat categories of unassessed species”. He added “our new methods are important for highlighting reptile species at risk and can be used on other groups as an initial shortcut for threat categorization”.
Shai Meiri added “Importantly, the additional reptile species identified as threatened by our models are not distributed randomly across the globe or the reptilian evolutionary tree. Our added information highlights that there are more reptile species in peril – especially in Australia, Madagascar, and the Amazon basin – all of which have a high diversity of reptiles and should be targeted for extra conservation effort. Moreover, species rich groups, such as geckos and elapids (cobras, mambas, coral snakes, and others), are probably more threatened than the Global Reptile Assessment currently highlights, these groups should also be the focus of more conservation attention”
Uri Roll mentioned “Our work could be very important in helping the global efforts to prioritize the conservation of species at risk – for example using the IUCN red-list mechanism. Our world is facing a biodiversity crisis, and severe man-made changes to ecosystems and species, yet funds allocated for conservation are very limited. Consequently, it is key that we use these limited funds where they could provide the greatest benefits. Advanced tools- such as those we have employed here, together with accumulating data, could greatly cut the time and cost needed to assess extinction risk, and thus pave the way for more informed conservation decision making”.

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Proportion of reptile species in different threat categories for an Automated Assessment Method and for the IUCN Red List of Threatened Species.
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Between a rock and a hard place – unique rare species face grave dangers due to human action

24/11/2021

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In a recent paper published in the journal Science Advances Gopal explored drivers of phylogenetically endemic land vertebrates. He also looked at conservation attributes of regions with high phylogenetically endemic species.

We live in the age of the ‘sixth mass extinction’. Our daily activities are causing hundreds and thousands of species to be lost forever. To turn the tide on the biodiversity crisis we have to identify those regions and species that are most in need of our conservation efforts. However, the characteristics of regions or species most in need of protection are not always clear. In this work we focus on those species that have two distinct features that make especially good candidates for conservation efforts. First – they are confined to only small and distinct location on the globe – what are known as endemic species and face greater risk of extinction. Second – they are evolutionary unique - they do not have close relatives on the ‘tree of life’ and their loss will represent a loss of millions of years of evolution. Species that poses both of these attributes (phylogenetic endemics) are therefore of great conservation importance as they represent unique and threatened components of biodiversity. To explore these species, we collected data regarding the evolutionary relationships and geographic distribution of almost all land vertebrate species (~30,000 species of amphibians, birds, mammals, and reptiles). We set out to map global ‘hotpots’ of such species, understand what are the unique conditions that support them, and evaluate their current protection and threats.
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Some of the range-restricted evolutionary unique species. The Red ruffed lemur (photo credit: Charles J Sharp), Madagascar fish eagle (photo credit: Anjajavy le Lodge), Hula painted frog (photo credit: Gopal Murali - own image), and Chinese Crocodile Lizard (photo credit: Holger Krisp). Images from Wikimedia Commons (apart from the painted frog).

We found that hotspots of phylogenetically endemic species mostly occur in the tropics and in the southern hemisphere along mountain ranges and in islands. Altogether, these hotspots, when combining the hotspots for all of the four above-mentioned groups, they occupy 22% of the total landmass. Hotspots that were important for all of the four groups are located in the Caribbean islands, Central America, along the Andes, eastern Madagascar, Sri Lanka, southern Western Ghats in India, and New Guinea. Although some of these regions have been previously prioritized for conservation actions, our study also found hotspots outside well-known biodiversity centres. For instance, we found the Asir mountains in Saudi Arabia to be important for such unique birds and Morocco to harbour phylogenetically endemic reptiles. Globally, these regions are mostly defined as mountainous tropical regions. This finding supports the notion that tropical mountains have an important role in the generation and maintenance of biodiversity.

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Global map of Phylogenetic endemism hotspots for all land vertebrates corrected for species richness

We next quantified how human activities and climate change are threatening these hotspots. Alarmingly, we found human activities such as buildings, roads, land-use, population density, and rate of climate change to be disproportionately higher in these hotspots (when compared to regions outside them). Consequently, our study highlights that many uniquely rare species, which probably perform important roles in the ecosystem, will be the first to be lost due to global change. Furthermore, we found most of the hotspots are not adequately protected. About 70% of the hotspots regions have less than 10% overlap with protected areas. Some of these regions which require urgent conservation action are the southern Andes, Horn of Africa, Southern Africa, and the Solomon Islands.
 
To-date most conservation strategies still focus on species-rich regions or flagship species, which may miss out on regions with uniquely rare species we identified. Overall, our study emphasizes on the need for strategic conservation policy and management to safeguard the persistence of thousands of small-ranged species that represent millions of years of unique evolutionary history.

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Infographic representing this work. Press to download in high resolution
Author: Gopal Murali
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Hiding in plain sight: rare lizards are more common than we think

23/11/2017

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In a recently published paper in Diversity and Distributions we try to illuminate aspects regarding the biology, and conservation of all narrow ranged lizard species, across the globe.
We defined lizard species with the smallest ranges as those only known from a single locality, with a maximum range extent no larger than 10 km. Surprisingly, more than 900 species, or roughly 1 in seven of all known lizard species, have such small ranges. Furthermore, about 750 of these species have never been seen again after their initial discovery, and more than 200 lizard species are only known to science from a single individual.
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Enyailoides altotambo from Ecuador ( Photo: Omar Torres Carvajal)
When exploring different attributes of small ranged species we found that most of them inhabit relatively inaccessible places in tropical climates worldwide. Furthermore, they are mostly small bodied species; many of them are active at night; and live in rocky habitats. Among the different lizard groups geckos and skinks dominate with many rare species.
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Riama yumborum from Ecuador (Photo: Omar Torres Carvajal)
Many of these species (such as those inhabiting small islands or caves) may truly have small ranges. However others may actually have larger ranges, and we are simply ignorant of the true extent of their distribution. This is especially true those found in remote, inaccessible places with no obvious barriers to their dispersal. Thus their small ranges are potentially only an artifact of our poor knowledge. Distinguishing between these two possibilities is both illuminating from an ecological and evolutionary perspective and extremely important from a conservation point of view.
 This work could help better focus conservation efforts by pointing at the species, and places, that are in the greatest need of protection. Many of the species, especially those which have not been observed for decades, may well be already extinct. However, to-date only six of the species studied have been officially recognized as such. In order to examine the true extent of such extinctions, and try to prevent future ones, the study provides invaluable information for directing future research and conservation efforts.
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Lizard species known only from their type localities. Circles: species not observed after 1967. Crosses: species observed after 1967.
Authors: Shai Meiri and Uri Roll
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A short history of GARD and how it has been used to highlight gaps in global conservation priorities

9/10/2017

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In a paper published in Nature Ecology and Evolution we present the first global maps of all reptiles - and thus complete the global distributions of all tetrapods. We further explore how the new reptile information changes how we think about global conservation priorities. As this is the first place where all of the GARD maps have been used and published, we use this opportunity to share some of the history of GARD itself, as well as the particular work that was carried out for this paper.

The beginnings of GARD
Planning for reptile conservation globally we first needed to map the distribution of all known species. About 8500 of them when we started in 2006, about 10,500 now recognized. This was a time when such global databases were being published for amphibians, birds, and mammals – some of us have been instrumental in assembling those databases, so we felt fairly confident we knew how it should be done.
What we were wondering, however, was whether the fact that reptile distributions were not collated at the time was not because it couldn’t be. A quick survey of available field guides and herpetology books revealed that maps of the sort used to assemble distribution data for birds and mammals were simply unavailable for huge parts of the world, including most of the crucial regions in tropical South America, Africa and Southern Asia.
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GARD meeting, Oxford (photo: Uri Roll)
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GARDians competing for that 'perfect' picture of a gecko
Thus the Global Assessment of Reptile Distribution working group (GARD) was formed. In the meantime we started recruiting the people who did much of the actual legwork – graduate students who digitized maps from existing sources, as well as the maps that started pouring in from the reptile experts among the GARD members. We had to keep track with constant taxonomic changes, species splits and new reptile species discoveries (many of them by GARD members themselves) – resulting in additional 200 species or reptiles nowadays being added annually.
We finally had at least some data for all the species or reptiles we thought one could map about two year ago. Then we met again to start the immensely important process of reviewing the distribution data to ensure errors were kept to the minimum (a process that is still ongoing).
Early on in compiling the data we got the feeling that lizard ‘hotspots’ were not in the tropics, where virtually all other groups studied so far have the most species. Once the maps were fully compiled this was very evident. The unique thermal requirements of reptiles enable them to thrive in drier habitats, allowing them to evolve and prosper in deserts.
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Vipera bornmuelleri (photo: Uri Roll)
Do unique reptilian biologies and ecologies demand particular conservation needs?
Or in other words do the major global conservation priorities designations adequately represent reptiles or do their unique distributions make them less protected. It turns out that many reptiles – predominantly lizards and turtles are left out of global priority regions and protected areas.
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Hypsilurus papuensis (photo: Alex Slavenko)
We therefore wanted to explore how the focus of future conservation efforts need to change to properly represent reptiles. To do this we run prioritization optimization procedures which enabled us to highlight various regions of the world predominantly in drylands, savannah, steppe, and also islands that increase in importance when reptile distribution data are added. More broadly this work highlights the need of getting better data for lesser known groups in order to compile truly inclusive conservation planning that encapsulates all of biodiversity.
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Ecoregions that increase in importance for conservation, when reptile data are added (dark blue - top decile ecoregions, light blue - top quartile ecoregions)​
Authors: Shai Meiri and Uri Roll
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Large and lonely - lately extinct reptiles were mostly on islands, and usually big

17/8/2016

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When exploring the extinction of Late Quaternary reptiles it seems that body-size was an important predictor of extinction rate. Larger reptiles were more likely to go extinct - published now in Global Ecology and Biogeograpy.
As extinction rates in our world increase at an alarming rate, proper conservation actions require detailed knowledge of the factors influencing extinction. These could be both anthropogenic pressured placed on natural environments, as well as particular species traits which make them especially vulnerable to these pressures. Over the last 50,000 years in which humans have spread across the Earth, there have been waves of mass extinctions of birds and mammals wherever humans colonized. These extinctions were particularly pronounced for large-bodied animals.
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Meiolania Platyceps
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Varanus priscus from the Melbourne Museum
We set out to examine if a similar pattern could be found for reptiles. In other words, we wanted to know if extinction also favored larger-bodied reptiles. We compiled data on body sizes of all currently known extant species of reptiles, just over 10,000 different species, as well as on 82 species of reptiles known to have gone extinct during the Late Quaternary, following human colonization of their original distribution ranges. By comparing the two groups, extant and extinct, we found that at least for lizards and turtles, extinct species were remarkably large.
Prime examples include the largest lizard to have ever lived, the Megalania monitor Varanus priscus, or the various species of giant tortoises on islands in the Indian and Pacific Oceans. By far the clearest pattern, however, is that extinctions mostly occurred on islands. Almost 90% of all extinct reptile species were endemic to islands!
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Hoplodactylus delcourti
The causes for these extinctions are numerous, and include over-harvesting by humans, introduction of invasive carnivores and rats, habitat change by human colonization, and possibly indirect cascade effects caused by the extinction of other, co-existing species. Our study helps us better understand the mechanisms of extinction in reptiles, and therefore might prove useful for pinpointing species which might be vulnerable to anthropogenic pressures in the future, and thus in need of conservation planning.
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localities of extinct late Quaternary reptiles
Author: Alex Slavenko
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Here be dragons – how new digital tools aid in exploring humans’ perceptions towards reptiles, and their conservation

4/5/2016

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In an article published in Biological Conservation we tallied the number of page-views each reptile species’ page in all of Wikipedia language editions had during 2014. We further correlated these numbers with various other attributes of the reptiles.
Highlights
  • We produced a global map of 55.5 million human-nature interactions
  • Wikipedia page views illuminate global scale patterns of human interest in nature
  • Different Wikipedia language editions reflect interests in their local fauna
  • Being large, venomous, threatened and described earlier makes a reptile interesting
  • Big-data approaches hold much promise for elucidating human-nature relationships
We found that venomous or endangered species, as well as those with higher body mass or posing a threat to humans, tended to be more interesting overall. There was also a bias towards species found in Wikipedia users' own regions – for example, the Japanese pit viper was top of the Japanese-language rankings, while the green iguana was the most-accessed species among Spanish speakers. With notable exceptions such as the sea turtle or Galapagos giant tortoise, species that are venomous or otherwise dangerous to humans seem to capture people's imaginations more than others. The Komodo dragon is found in a geographical area probably the size of a small English county, yet it consistently attracts the most attention – possibly because the idea of the dragon is so universal in myth and folklore.
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Komodo dragon - Varanus komodoensis
There is a debate in conservation as to whether the fact that we as humans like a particular species justifies conserving it, regardless of its importance from an ecological point of view. But although this idea of some species being "culturally valuable" has been around for some time, it has been difficult to measure and define. Whether or not we want to take these cultural variables into account when shaping conservation policy, we need data to support those decisions. In our study we looked at 55.5 million page views in the year 2014 for all of the 10,002 species of reptile accessed in Wikipedia.
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Black mamba - Dendroaspis polylepis
In the past we could have carried out basic surveys of a few hundred or a few thousand individuals to find out where their interest lay, whereas now we can do it with millions of people for an entire class of organisms on a global scale. Obviously there are limitations to using an online tool such as Wikipedia, but there are lots of benefits too. One of the key questions in conservation is where to divert the limited resources we have available. Do we prioritise rare or endangered species, ecologically important species, or species that attract the most public interest? The field is definitely split, but we're putting numbers behind some of these ideas, and that’s really important.
Among more traditional conservationists there may be the view that we shouldn't incorporate cultural values into decisions about policy or funding. However, the fact is that whether we like it or not, we already do – how much funding do lions get compared with, for example, a species of small snail that doesn't even have an English name, even if the snail is more at risk of going extinct? The biases are already there. There's also an argument that the traditional thinking around conservation hasn't quite worked, so we need to reframe our approach. Regardless of the point of view you take, having this sort of quantitative data is critical.

The findings of this article have been picked up by several news outlets such as The Guardian, Haaretz Daily Newspaper, as well as Mongabay, Oxford University news and many others.
Authors: John C. Mittermeier and Uri Roll
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