ZSL SCIENCE REVIEW | IMPACT AREAS Monitoring lesser- IMPACT known biodiversity AREA Determining the status of the world’s species is important to track progress towards global environmental targets – and IoZ leads the way. IoZ is at the forefront of monitoring global in putting reptile conservation in the biodiversity and developing scientifically international spotlight. robust indicators to track progress towards Our recent work focused on predicting targets such as the Aichi Targets of the extinction risk by investigating species- Convention on Biological Diversity, assessing specific factors that correlate with conservation actions and measuring human extinction risk, and by employing novel impact on biodiversity. machine-learning techniques to determine Monitoring species with very few the true extinction risk of species currently data, such as less well-studied reptiles, listed as Data Deficient. In addition to reptile invertebrates and plants, is a challenge for species with a smaller range size having science. Over recent years, IoZ has increased a higher risk of extinction, our research our knowledge of the extinction risk of found that at smaller range sizes, habitat reptiles, freshwater molluscs, dung beetles specialisation and accessibility of a species Main image: reptiles and crayfish, among others. Reptiles provide range to humans became important in the conservation us with an excellent group for testing how predictors of extinction risk (Böhm et al. spotlight: lyre head lizard to assess and monitor species 2016a). This suggests that (Lyriocephalus scutatus) trends when data are scarce, extinction risk may be Inset left: Usambara eyelash viper (Atheris ceratophora), data deficiency is high, and predicted by models based Vulnerable on the IUCN Red species groups are highly on range size, coupled List due to restricted range in the montane rainforests species-rich, making with other key of Tanzania, an area complete assessments factors, so as to affected by high rates of deforestation; the species is of the whole discriminate between also assessed to be highly group time- and threatened and sensitive to climate change resource-consuming. non-threatened range- restricted species. Extinction risk IoZ researchers estimate extinction risk not only for Data in reptiles and collaborators also Deficient species, but also for previously In partnership with the investigated the true status unassessed ones. International Union for of Data Deficient species using Conservation of Nature (IUCN), IoZ more complex models, specifically Measuring range for researchers are developing and refining the machine-learning techniques. Essentially, extinction risk assessments Sampled Red List Index. This indicator relies we trained a computer to discriminate For many lesser-known species, for which on repeated assessments of the extinction between threatened and non-threatened we lack estimates of population trends over risk for a random sample of 1,500 species, species by deriving decisions based on time, range size becomes an important to assess status and trends in the extinction species-specific data (for example, biological criterion for assessing extinction risk under risk of megadiverse species groups. Previous traits such as size and longevity, and the IUCN Red List Categories and Criteria. work using this sampled approach, led by IoZ environmental factors such as climate and These criteria arguably provide the most researchers with help from more than 200 human impact). We found that 19% of Data comprehensive and scientifically robust reptile experts, estimated that one in five Deficient reptiles are likely to be threatened system for assessing species extinction risk. reptile species is threatened with extinction. with extinction (Bland and Böhm, 2016). IoZ has been involved in the development This research has been instrumental Therefore, our models may provide a timely of the current IUCN Red List criteria since and efficient way to dramatically increase their inception in 2001. In the past year, our knowledge of the extinction risk of work primarily focused on the effects Learn more about previously under-studied species groups. of inconsistently estimating extent of the Red List at We are now refining and testing these occurrence (EOO), which is a key measure iucnredlist.org models on other species groups, so we can of extinction risk. This work highlighted that, 10 | SCIENCE REVIEW 2015/2016 | zsl.org IoZ research indicated that 22% of reptile species were highly vulnerable to while a one-time downlisting of hundreds Unit to refine climate climate change more robust, and of species may be required (as extinction change vulnerability deliver climate change risk may be lower for these species than assessments. These vulnerability assessments previously estimated), estimating EOO as assessments use species- for other species groups, a strict minimum convex polygon – as in specific trait and environmental particularly invertebrates. IUCN Red List guidance – ultimately ensures data relating to climate change to consistency across assessments and realigns assess the vulnerability of species to climate the calculation of EOO with the theoretical change. While such assessments have been basis on which the metric was founded carried out globally for better-known species References Bland, LM and Böhm, M (2016) Overcoming data deficiency (Joppa et al. 2015). groups, IoZ researchers published a first in reptiles. Biological Conservation. DOI: 10.1016/j.biocon. assessment of climate change vulnerability 2016.05.018 Emerging threats from climate change for a sampled assessment of nearly 1,500 Böhm, M, Williams, R, Bramhall, HR, McMillan, KM, Davidson, AD, Garcia, A, Bland, LM, Bielby, J and Collen, B (2016a) Correlates of Climate change represents an often slow- reptile species. Our results indicate that extinction risk in squamate reptiles: the relative importance of biology, geography, threat and range size. Global Ecology and acting threat, potentially affecting species 22% of reptile species were highly vulnerable Biogeography. DOI: 10.1111/geb.12419 over longer time periods than those to climate change (Böhm et al. 2016b). Böhm, M, Cook, D, Ma, H, Davidson, AD, García, A, Tapley, B, considered in IUCN Red List assessments. Overlap between climate change-vulnerable Pearce-Kelly, P and Carr, J (2016b) Hot and bothered: using trait-based approaches to assess climate change vulnerability Climate change may therefore not feature species and species threatened on the in reptiles. Biological Conservation. DOI:10.1016/j. as prominently on the Red List as other IUCN Red List is very limited, suggesting biocon.2016.06.002 Joppa, LN, Butchart, SHM, Hoffmann, M, Bachman, SP, Akçakaya, threats, such as habitat loss, invasive that climate change will present new and HR, Moat, JF, Böhm, M, Holland, RA, Newton, A, Polidoro, B and species and pollution. IoZ researchers are additional conservation priorities. Work is Hughes, A (2015) Impact of alternative metrics on estimates of extent of occurrence for extinction risk assessment. Conservation working with the IUCN Climate Change ongoing to make the assessment process Biology 30(2): 362-370. DOI: 10.1111/cobi.12591 zsl.org | SCIENCE REVIEW 2015/2016 | 11.