About the GMA


The Global Mammal Assessment (GMA) is a program carried out at the Department of Biology and Biotechnologies, Sapienza University of Rome, a member of the IUCN Red List Partnership. Our laboratory includes a mix of researchers, PhD students, Masters students and Program Officers dedicated to the assessment of mammal extinction risk, the development of mammal distribution maps, and the forecast of scenarios of future mammal loss driven by global change. The tasks of the GMA program include:

  • Keeping up to date information on the ecology, distribution, status and threats to all mammal species worldwide and updating the IUCN Red List of Threatened Species.
  • Coordinating together with over 35 mammal Specialist Groups (within the IUCN Species Survival Commission) to help bring the best science to bare to improve decision making.
  • Prioritizing regions of the world, species, and conservation actions to prevent extinctions with the available conservation resources.
  • Publishing key findings in scientific and general literature to advance the science and policies surrounding mammal conservation efforts.

We aim to support conservation decisions with the best available mammal data globally.

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GMA lab and Satellite Remote Sensing for Biodiversity

front-matterCheck out the recent ISSUE N. 369 of Philosophical Transactions B on Satellite remote sensing for biodiversity research and conservation applications. This issue includes two articles with coordination/participation of GMA lab members.

Wegmann, M, Santini L, Leutner B, Safi K, Rocchini D, Bevanda M, Latifi, H, Dech S, Rondinini C. 2014 Role of African protected areas in maintaining connectivity for large mammals. Phil. Trans. R. Soc. B 369: 20130193. Download the PDF or ask us for a copy.

Di Marco M, Buchanan GM, Szantoi Z, Holmgren M, Grottolo Marasini G, Gross D, Tranquilli S, Boitani L, Rondinini C. 2014 Drivers of extinction risk in African mammals: the interplay of distribution state, human pressure, conservation response and species biology. Phil. Trans. R. Soc. B 369: 20130198. Download the PDF or ask us for a copy.


Incorporating spatial population structure in gap analysis reveals inequitable assessments of species protection


Diversity & Distribution DOI: 10.1111/ddi.12198

Quartz %dGap analysis measures the percentage of protected species distribution and generally compares it to a representation target (i.e. minimum area to be protected). The results are used to identify species that need further protection, providing a quantitative baseline to address a possible expansion of a given protected area (PA) systems. However, the achievement of the same representation target may have different implications in terms of species persistence depending on population spatial structure and conservation needs. The aim was to investigate to what extent and why gap analysis may provide inequitable assessments of species protection.

We performed three gap analyses on 27 European species of carnivores and ungulates, measuring the level of protection according to three different types of distribution data: geographical ranges, habitat suitability models and habitat suitability models that incorporate the potential spatial structuring in populations within PAs.

The estimated degree of species protection depends on the distribution proxy and the target adopted. When the analyses are based on areas able to support viable populations (irrespective of how these areas are quantified), the perceived relative protection of different species changes considerably. The ability of different species to persist in PA systems mostly depends on their population density and dispersal abilities, as well as the interaction between these two features, which eventually determines the number and relative size of the populations.

The achievement of the same representation target for different species may imply protecting different numbers of individuals in populations having different spatial structures and may consequently lead to different probabilities of persistence across species. If species spatial structuring is disregarded, gap analysis may thus lead to inequitable assessments of PA coverage.


A Retrospective Evaluation of the Global Decline of Carnivores and Ungulates

Conservation Biology DOI: 10.1111/cobi.12249

Di Marco Fig 2

Trend in aggregated conservation status of small-bodied and large-bodied carnivores and ungulates (represented with the IUCN Red List Index, RLI) .



Assessing temporal changes in species extinction risk is necessary for measuring conservation success or failure and for directing conservation resources toward species or regions that would benefit most. Yet, there is no long-term picture of genuine change that allows one to associate species extinction risk trends with drivers of change or conservation actions. Through a review of 40 years of IUCN-related literature sources on species conservation status (e.g., action plans, red-data books), we assigned retrospective red-list categories to the world’s carnivores and ungulates (2 groups with relatively long generation times) to examine how their extinction risk has changed since the 1970s. We then aggregated species’ categories to calculate a global trend in their extinction risk over time. A decline in the conservation status of carnivores and ungulates was underway 40 years ago and has since accelerated. One quarter of all species (n = 498) moved one or more categories closer to extinction globally, while almost half of the species moved closer to extinction in Southeast Asia. The conservation status of some species improved (toward less threatened categories), but for each species that improved in status 8 deteriorated. The status of large-bodied species, particularly those above 100 kg (including many iconic taxa), deteriorated significantly more than small-bodied species (below 10 kg). The trends we found are likely related to geopolitical events (such as the collapse of Soviet Union), international regulations (such as CITES), shifting cultural values, and natural resource exploitation (e.g., in Southeast Asia). Retrospective assessments of global species extinction risk reduce the risk of a shifting baseline syndrome, which can affect decisions on the desirable conservation status of species. Such assessments can help conservationists identify which conservation policies and strategies are or are not helping safeguard biodiversity and thus can improve future strategies.

Check out a recent Nature Research Highlight on this paper.

Effects of Errors and Gaps in Spatial Data Sets on Assessment of Conservation Progress

Conservation Biology 27, 1000-1010.

Data on the location and extent of protected areas, ecosystems, and species’ distributions are essential for determining gaps in biodiversity protection and identifying future conservation priorities. However, these data sets always come with errors in the maps and associated metadata. Errors are often overlooked in conservation studies, despite their potential negative effects on the reported extent of protection of species and ecosystems. We used 3 case studies to illustrate the implications of 3 sources of errors in reporting progress toward conservation objectives: protected areas with unknown boundaries that are replaced by buffered centroids, propagation of multiple errors in spatial data, and incomplete protected-area data sets. As of 2010, the frequency of protected areas with unknown boundaries in the World Database on Protected Areas (WDPA)
caused the estimated extent of protection of 37.1% of the terrestrial Neotropical mammals to be overestimated by an average 402.8% and of 62.6% of species to be underestimated by an average 10.9%. Estimated level of protection of the world’s coral reefs was 25% higher when using recent finer-resolution data on coral reefs as opposed to globally available coarse-resolution data. Accounting for additional data sets not yet incorporated
into WDPA contributed up to 6.7% of additional protection tomarine ecosystems in the Philippines. We suggest ways for data providers to reduce the errors in spatial and ancillary data and ways for data users to mitigate the effects of these errors on biodiversity assessments.

Comparing multiple species distribution proxies and different quantifications of the human footprint map, implications for conservation

Moreno Di Marco, Carlo Rondinini, Luigi Boitani, Kris A. Murray (2013)
Biological Conservation 165: 203-211

Anthropogenic threats drive species to extinction and are the focus of extinction risk analyses and conservation planning. Threats are often quantified through higher level proxies, such as the human footprint (HF). We tested the effects that multiple methods of representing species’ distribution and different quantifications of a HF map have on threat measurement, and how these influence conservation decisions. We quantified the magnitude of HF for 901 Southeast Asian mammals according to several methods. We ranked the species according to the measured HF value, and produced priority lists of
top-impacted species. The different representations of species’ distribution caused significant disagreement in HF calculations. HF values were on average lower when calculated in species’ suitable habitat or occurrence points in comparison to the whole geographic range. Biases were non-linear and dependent on distal factors, such as the proportion of suitable habitat within species’ range and species’ habitat specialism.
Using different HF quantifications also yielded disagreement, with 2–56% difference observed in species membership among priority lists. Threatened species were best predicted, and significantly placed in the top-ranking, when measuring their proportion of range exposed to high levels of HF. We thus show that the HF extent, not only its average value, determines species extinction risk. A well framed global conservation strategy must address the quantification of human impact on biodiversity. The selection of quantification methods has implications for how such impact is evaluated. Improving
techniques to quantify biodiversity threats will enhance the effectiveness of extinction risk analyses and conservation decisions.

Generation length for mammals

Pacifici M, Santini L, Di Marco M, Baisero D, Francucci L, Grottolo Marasini G, Visconti P, Rondinini C (2013) Generation length for mammals. Nature Conservation 5: 87–94. doi: 10.3897/natureconservation.5.5734. Resource ID: Dryad key: 10.5061/dryad.gd0m3

Generation length (GL) is defined as the average age of parents of the current cohort, reflecting the turnover rate of breeding individuals in a population. GL is a fundamental piece of information for population ecology as well as for measuring species threat status (e.g. in the IUCN Red List). Here we present a dataset including GL records for all extant mammal species (n=5427). We first reviewed all data on GL published in the IUCN Red List database. We then calculated a value for species with available reproductive parameters (reproductive life span and age at first reproduction). We assigned to missing-data species a mean GL value from congeneric or confamilial species (depending on data availability). Finally, for a few remaining species, we assigned mean GL values from species with similar body mass and belonging to the same order. Our work provides the first attempt to complete a database of GL for mammals; it will be an essential reference point for all conservation-related studies that need pragmatic information on species GL, such as population dynamics and applications of the IUCN Red List assessment.

Tragelaphus scriptus, generation length 1914,548 days

Tragelaphus scriptus, generation length 1914,548 days

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Ecological correlates of dispersal distance in terrestrial mammals

Santini L., Di Marco M., Visconti P., Baisero D., Boitani L., Rondinini C. 2013. Ecological correlates of dispersal distance in terrestrial mammals. Hystrix 24(2): 1-6.

Abstract. Dispersal distance in mammals is a fundamental information for several ecological and conservation applications. Although dispersal can depend on many intrinsic and extrinsic factors, in recent years many studies have shown that it scales with body size and home range area. However, the role of further ecological correlates to distance travelled is still unclear and the predictive models proposed so far have suffered from small sample size and lack of error estimates. This reduces the practical relevance of the models for ecological and conservation applications. We conducted a comprehensive meta-analysis on 327 studies on the dispersal of 164 mammal species, and performed linear and non-linear regression analyses to explore the relationships of body size and home range area with dispersal distance. We tested the effect of various life history traits and ecological factors on the relationships and performed a sensitivity analysis to evaluate the robustness of the models to sample size. The linear relationships of both home range and body size with dispersal distance were influenced by various life history traits and ecological factors. We developed allometric functions to estimate species dispersal distance based on different predictors and life history traits. Linear models representing the relationship between dispersal distance and body size or home range area received good support; however logistic models better approximates both relationships. Despite receiving less support than a logistic curve, a linear model between dispersal and home range is a good approximation for applicative purposes. Sensitivity analysis showed that our results are robust to subsampling of the original dataset until a sample of 40 species. Our empirical models have the potential to improve theoretical and applied population biology studies by extending the applicability and improving the accuracy of dispersal distance estimation to a large number of mammals.

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Update or outdate: Long-term viability of the IUCN Red List

Rondinini, C., Di Marco, M., Visconti, P., Butchart, S.M., Boitani, L. (2013) Update or outdate: long-term viability of the IUCN Red List. Conservation Letters. doi: 10.1111/conl.12040

Abstract. It is estimated that the global yearly expenditure on biodiversity conservation
action exceeds one billion U.S. dollars. One of the key tools for prioritizing conservation actions is the International Union for Conservation of Nature (IUCN) Red List, the most authoritative and comprehensive source of information on the global extinction risk of species (covering ca. 60,000 as of today). While IUCN’s vision is to increase the taxonomic coverage of the Red List, no adequate plan exists to keep it up to date. As species assessments become outdated after 10 years under IUCN rules, our simulations reveal that with the limited budget currently available for reassessment, most of the Red Listing effort may be wasted soon. Indeed, 17% of the species’ assessments are already outdated. To minimize the budget needed to keep assessments up to date in the Red
List, we propose a mixed strategy of online reassessments and budget growth. We show that largely replacing workshops with online consultations is a more sustainable strategy that would save U.S. $2.8 million per year (35% of the budget). Sharing the cost of such a strategy among Organization for Economic Co-operation and Development (OECD) countries (U.S. $156,000 per country per year) would ensure that the multimillion dollar spending based on the Red List remains effective in the long term.


Upcoming seminar at the Zoological Society of London

On 10th December 2012, Moreno Di Marco will present some of the GMA current projects during a seminar at ZSL.

Mammal species decline: past trend, current challenge, and possible conservation strategies

One quarter of all mammal species are today threatened with extinction, with both recent trends and future predictions pointing toward an imminent increase of that proportion. We investigate mechanisms and processes behind this decline and describe: (i) past trends in species extinction risk, (ii) cost-efficient conservation priorities and (iii) methodological challenges in measuring human impact on species.
(i) Unlike birds or amphibians, little is known about the global extinction risk status of mammals before 1996. By collecting past information on the status of carnivores and ungulates, we calculated past trends in extinction risk for those species, and show spatial and temporal patterns in global species decline from the ’70s up to date. (ii) Current approaches at setting global conservation priorities generally focus on species with high extinction risk, species that may be hard to save. We took a different approach and detected terrestrial mammals that are currently threatened with extinction, but highly likely to recover (due to their biological traits). We show that many of them are excluded from existing conservation initiatives, while reducing human impact on those species represents a cost-effective conservation strategy. (iii) Threat quantification varies with methodology and the effect of this variability remains largely unexplored. We show how different methods, to quantify the human impact on mammals, result in values that differ largely among each other. This may lead to potentially mismatching interpretations for conservationists, and we discuss practical guidelines for application.
An understanding of the biological and anthropogenic factors affecting global mammal decline and a consideration of the existing methodological challenges, will help conservation strategies to invert the current trend in global mammal decline.