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”.

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.

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.

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.

Author: Gopal Murali

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.

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.

 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.

Authors: Shai Meiri and Uri Roll

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.

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.

Author: Alex Slavenko