ReviewPRIMATOLOGY

Impending extinction crisis of the world’s primates: Why primates matter

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Science Advances  18 Jan 2017:
Vol. 3, no. 1, e1600946
DOI: 10.1126/sciadv.1600946
  • Fig. 1 Global primate species richness, distributions, and the percentage of species threatened and with declining populations.

    Geographic distribution of primate species. Numbers in red by each region refer to the number of extant species present. The bars at the bottom show the percent of species threatened with extinction and the percent of species with declining populations in each region. Percentage of threatened species and percentage of species with declining populations in each region from tables S1 to S4. Geographical range data of living, native species from the IUCN Red List (www.iucnredlist.org) are overlaid onto a 0.5° resolution equal-area grid. In cases in which a species’ range was split into multiple subspecies, these were merged to create a range map for the species. Mainland Africa includes small associated islands.

  • Fig. 2 Percent of species threatened with extinction in each primate family.

    Assessment of threat level is according to the IUCN Categories and Criteria VU (Vulnerable), EN (Endangered), and CR (Critically Endangered). Number in parentheses after each family indicates the number of species recognized in the family. Data for each species are indicated in tables S1 to S4. Notably, there are threatened species in all 16 primate families. Ten families have more than 50% of their species threatened (broken line at 50%). Note that the graph is only for the Threatened IUCN categories. Families not showing 100% values may have some species classified as Near Threatened (NT), Least Concern (LC), Data Deficient (DD), and Not Evaluated (NE) (see tables S1 to S3). Upon revision of the taxonomy of Malagasy lemurs, a number of taxa once thought to be widespread are now highly threatened; a similar scenario is envisioned for the galagids, where there appears to be a large number of newly recognized species with limited ranges. Taxonomy is based on previous works (13).

  • Fig. 3 Agricultural expansion and declines in forest cover for the period 1990–2010 in primate range regions.

    A rapid expansion of agriculture in primate range regions has been paralleled by a sharp decline in forest cover in the 20-year period considered. Trends for each individual region are shown in fig. S6 (A to C). Data for Africa include Madagascar (source of raw data, FAOSTAT: faostat.fao.org/site/377/DesktopDefault.aspx?PageID=377#ancor. Consulted June 2016).

  • Fig. 4 Global patterns of forecasted agricultural expansion for the 21st century in primate range regions and estimated range contraction.

    (A) Estimated current global primate distributions. (B) The predicted 21st century expansion of agriculture estimates a spatial overlap with about 75% of primate species habitat worldwide. Red areas indicate higher spatial overlap between agricultural expansion and primate habitat. Blue areas indicate limited spatial conflict. Agricultural expansion represents a synthesis of the expected increase in the location and area devoted to agricultural production, according to the land-cover map produced by the Integrated Model to Assess the Global Environment and potential productivity obtained from the Global Agro-Ecological Zones (Supplementary Text) (13). (C) Estimated range contraction in primate distributions by the end of the 21st century under a worst-case scenario of agricultural expansion. See Supplementary Text for methods.

  • Fig. 5 Phylogenetic signal as a predictor of extinction risk in the world’s primates.

    Distribution of threat values (IUCN Red List categories) for 340 primate species. Representative genera labeled. After taxonomic updates, our working phylogeny included 350 of the 367 species considered in the molecular supertree (73), of which 340 are not Data Deficient. Closely related species are more likely to have the same threat status than species taken randomly from the phylogeny [D = 0.31; P (D < 1) < 0.001], supporting a strong phylogenetic signal (see Supplementary Text for details of methodology). Data for Africa include Madagascar. IUCN Red List Categories: CR (Critically Endangered), EN (Endangered), VU (Vulnerable), NT (Near Threatened), and LC (Least Concern).

  • Fig. 6 Factors driving primate population declines and possible mitigating approaches.

    Four broad social and economic processes drive the proximate causes of threat to primates and human actions that directly affect primate habitats and populations. Mitigating approaches aim at lowering the impact of proximate causes of primate declines. Infrastructure development also includes road and rail expansion.

  • Fig. 7 Photos of selected primates from each major world region.

    Conservation status and photo credits include the following: (A) Golden snub-nosed monkey (Rhinopithecus roxellana), Endangered, P. A. Garber. (B) Ring-tailed lemur (Lemur catta), Endangered, R. A. Mittermeier. (C) Udzungwa red colobus (P. gordonorum), Endangered (Photo Credit: Thomas Struhsaker, Duke University). (D) Javan slow loris (Nycticebus javanicus), Critically Endangered (Photo Credit: Andrew Walmsley, Andrew Walmsley Photography). (E) Sumatran orangutan (P. abelii), Critically Endangered (Photo Credit: Perry van Duijnhoven). (F) Azara’s night monkey (Aotus azarae), Least Concern [Photo Credit: Claudia Valeggia (Yale University)/Owl Monkey Project, Formosa-Argentina].

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/3/1/e1600946/DC1

    fig. S1. Primate habitat countries ranked by the number of species present.

    fig. S2. Countries with primate species in the Neotropics, Africa (including Madagascar), and Asia and percent of countries with threatened species.

    fig. S3. IUCN threat categories and population status of primate species.

    fig. S4. Percent of primate species listed under each proximate threat, according to the IUCN.

    fig. S5. Growth trends in cattle stock, agricultural activity, and deforestation in primate range regions.

    fig. S6. Agricultural expansion and declines in forest cover for the period 1990–2010 in the Neotropics, Africa, and Asia.

    fig. S7. Human population growth in primate range regions.

    fig. S8. Global primate trade for the period 2005–2014, as reported by parties to the CITES Secretariat.

    fig. S9. Phylogenetic patterns associated with extinction risk for primate species in the Neotropics, Africa, and Asia.

    fig. S10. Number of published articles found in the Web of Science for primate species in each family.

    table S1. Primate species in the Neotropics grouped by family.

    table S2. Primate species in mainland Africa grouped by family.

    table S3. Primate species in Madagascar grouped by family.

    table S4. Primate species in Asia grouped by family.

    table S5. Summary of sources of threat and the number of primate species affected, according to the IUCN Red List.

    table S6. Global international trade in primates for the period 2005–2014, as reported by parties to the CITES Secretariat.

    Supplementary Text

    References (167209)

  • Supplementary Materials

    This PDF file includes:

    • fig. S1. Primate habitat countries ranked by the number of species present.
    • fig. S2. Countries with primate species in the Neotropics, Africa (including Madagascar), and Asia and percent of countries with threatened species.
    • fig. S3. IUCN threat categories and population status of primate species.
    • fig. S4. Percent of primate species listed under each proximate threat, according to the IUCN.
    • fig. S5. Growth trends in cattle stock, agricultural activity, and deforestation in primate range regions.
    • fig. S6. Agricultural expansion and declines in forest cover for the period 1990–2010 in the Neotropics, Africa, and Asia.
    • fig. S7. Human population growth in primate range regions.
    • fig. S8. Global primate trade for the period 2005–2014, as reported by parties to the CITES Secretariat.
    • fig. S9. Phylogenetic patterns associated with extinction risk for primate species in the Neotropics, Africa, and Asia.
    • fig. S10. Number of published articles found in the Web of Science for primate species in each family.
    • table S1. Primate species in the Neotropics grouped by family.
    • table S2. Primate species in mainland Africa grouped by family.
    • table S3. Primate species in Madagascar grouped by family.
    • table S4. Primate species in Asia grouped by family.
    • table S5. Summary of sources of threat and the number of primate species affected, according to the IUCN Red List.
    • table S6. Global international trade in primates for the period 2005–2014, as reported by parties to the CITES Secretariat.
    • Supplementary Text
    • References (167–209)

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