MORENO DI MARCO & LUCA SANTINI

Global Change Biology, DOI: 10.1111/gcb.12834

Mean values of geographic range size in terrestrial mammals.

Geographic range size is the manifestation of complex interactions between intrinsic species traits and extrinsic environmental conditions. It is also a fundamental ecological attribute of species and a key extinction risk correlate. Past research has primarily focused on the role of biological and environmental predictors of range size, but macroecological patterns can also be distorted by human activities. Here we analyse the role of extrinsic (biogeography, habitat state, climate, human pressure) and intrinsic (biology) variables in predicting range size of the world’s terrestrial mammals. In particular, our aim is to compare the predictive ability of human pressure vs species biology. We evaluated the ability of 19 intrinsic and extrinsic variables in predicting range size for 4,867 terrestrial mammals. We repeated the analyses after excluding restricted-range species and performed separate analyses for species in different biogeographic realms and taxonomic groups. Our model had high predictive ability, and showed that climatic variables and human pressures are the most influential predictors of range size. Interestingly, human pressures predict current geographic range size better than biological traits. These findings were confirmed when repeating the analyses on large-ranged species, individual biogeographic regions and individual taxonomic groups. Climatic and human impacts have determined the extinction of mammal species in the past, and are the main factors shaping the present distribution of mammals. These factors also affect other vertebrate groups globally, and their influence on range size may be similar as well. Measuring climatic and human variables can allow to obtain approximate range size estimations for data deficient and newly discovered species (e.g. hundreds of mammal species worldwide). Our results support the need for a more careful consideration of the role of climate change and human impact – as opposed to species biological characteristics – in shaping species distribution ranges.

Check 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.

M. DI MARCO, L. BOITANI, D. MALLON, M. HOFFMANN, A. IACUCCI, E. MEIJAARD, P. VISCONTI, J. SCHIPPER, C. RONDININI
Conservation Biology DOI: 10.1111/cobi.12249

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.

VISCONTI, P. M. DI MARCO, J. G. ALVAREZ-ROMERO, S. R. JANUCHOWSKI-HARTLEY, R.L. PRESSEY, R. WEEKS AND C. RONDININI. 2013.
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.

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.