Before conservation can begin, it is essential to know where in the world species needing protection actually are. While there may be fairly comprehensive distribution maps already in existence to cover many of the world’s birds, mammals and other tetrapods (defined as four-limbed animals, as well as their descendants such as whales and snakes) there has been a distinct lack of knowledge gathered about the many reptile species which inhabit the planet.
‘More people like birds and mammals, and we know them better,’ explains Shai Meiri, from the Department of Zoology at Tel Aviv University. ‘There are a hundred bird lovers to any one reptile lover. The same goes for professionals. Birds are in the public eye, they symbolise good things and cannot kill you the way some reptiles can. Mammals are furry, fluffy and adorable, and we are mammals ourselves, so we connect.’
Meiri and the rest of the Global Assessment of Reptile Distributions (GARD) group have therefore spent 12 years collating data in order to create the first detailed maps for the distribution of 10,064 reptile species around the world. This breaks down as: 6,110 species of lizards, 3,414 species of snakes, 322 turtle species, 193 species of Amphisbaenia ‘worm lizards’, 24 types of crocodile, and the single species of New Zealand tuatara.
‘I think the key surprise was how different some of the subgroups were,’ says Meiri. ‘Snakes showed the classical patterns that all other known taxa did. Lizards have a more patchy framework of hotspots and coldspots, they are sometimes very diverse in arid regions – especially in Australia – and sometimes not, sometimes very diverse in the tropics, and sometimes not so much, and they differ from other reptiles. We guessed all would be fairly similarly distributed, but they are not.’
Mapping the ranges of all the world’s reptiles reveals that while general conservation measures in spaces which are effective for the protection of mammals, birds, and amphibians are shown to also be effective ways of protecting numbers of species with large range sizes (such as snakes), they tend not to serve the interests of more ‘patchy’ reptiles, such as turtles and lizards. Turtles in particular have a range far outside the norm, with hotspots in the southern states of the US and Bangladesh, while populations of other tetrapods are generally found in highest concentrations across South America and sub-Saharan Africa.
‘Once we realised this was the case, we went ahead to identify the gaps in current conservation priorities that would give the best “return on investment” for the protection of reptiles, together with the other groups,’ explains Uri Roll, from the Mitrani Department of Desert Ecology at Ben-Gurion University of the Negev – another member of the GARD group. ‘We have done this by constructing a formal conservation optimisation procedure, in which we try to capture as many representatives of all species as possible while minimising the areas needed for their protection, as at the end of the day resources needed for conservation are limited.’ Roll was able to identify those regions that are generally important for the conservation of all land vertebrates, and how they have increased in importance due to the inclusion of the new reptile information.
The data also raises questions about how conservationists can respond to ensure a wide-ranging approach to protecting all reptiles, not just those which happen to crossover with the needs of other tetrapods. ‘People need to work from the head and not from the gut,’ says Meiri. ‘We need to find measurable indices for diversity protection – we have them, and we in academia use them – not to act when planning for conservation according to which species is more charismatic. You act in the best way available data – and much is still unavailable – dictate.’
This was published in the December 2017 edition of Geographical magazine.