Community-based management, ecotourism, and researchers' presence are proposed to prevent lemur extinctions.

Primates occur in 90 countries, but four—Brazil, Madagascar, Indonesia, and the Democratic Republic of the Congo (DRC)—harbor 65% of the world’s primate species (439) and 60% of these primates are Threatened, Endangered, or Critically Endangered (IUCN Red List of Threatened Species 2017-3). Considering their importance for global primate conservation, we examine the anthropogenic pressures each country is facing that place their primate populations at risk. Habitat loss and fragmentation are main threats to primates in Brazil, Madagascar, and Indonesia. However, in DRC hunting for the commercial bushmeat trade is the primary threat. Encroachment on primate habitats driven by local and global market demands for food and non-food commodities hunting, illegal trade, the proliferation of invasive species, and human and domestic-animal borne infectious diseases cause habitat loss, population declines, and extirpation. Modeling agricultural expansion in the 21st century for the four countries under a worst-case-scenario, showed a primate range contraction of 78% for Brazil, 72% for Indonesia, 62% for Madagascar, and 32% for DRC. These pressures unfold in the context of expanding human populations with low levels of development. Weak governance across these four countries may limit effective primate conservation planning. We examine landscape and local approaches to effective primate conservation policies and assess the distribution of protected areas and primates in each country. Primates in Brazil and Madagascar have 38% of their range inside protected areas, 17% in Indonesia and 14% in DRC, suggesting that the great majority of primate populations remain vulnerable. We list the key challenges faced by the four countries to avert primate extinctions now and in the future. In the short term, effective law enforcement to stop illegal hunting and illegal forest destruction is absolutely key. Long-term success can only be achieved by focusing local and global public awareness, and actively engaging with international organizations, multinational businesses and consumer nations to reduce unsustainable demands on the environment. Finally, the four primate range countries need to ensure that integrated, sustainable land-use planning for economic development includes the maintenance of biodiversity and intact, functional natural ecosystems.

The unique primates of south-eastern Madagascar face threats from growing human populations. The country's extant primates already represent only a subset of the taxonomic and ecological diversity existing a few thousand years ago. To prevent further losses remaining taxa must be subjected to effective monitoring programmes that directly inform conservation efforts. We offer a necessary first step: revision of geographic ranges and quantification of habitat area and population size for diurnal and cathemeral (active during both day and night) lemurs. Recent satellite images are used to develop a forest cover geographical information system, and censuses are used to establish range boundaries and develop estimates of population density and size. These assessments are used to identify regions and taxa at risk, and will be a useful baseline for future monitoring of habitat and populations. Precise estimates are impossible for patchily-distributed taxa (especially Hapalemur aureus, H. simus and Varecia variegata variegata); these taxa require more sophisticated modelling.

We examined a purported lemur (Eulemur fulvus rufusxE. albocollaris) hybrid zone at Andringitra, Madagascar, using sequences from five genes (one mitochondrial gene (d-loop) and four nuclear introns (hemopexin, malic enzyme, ceruloplasmin, and microsatellite 26 flanking region)), from 60 individuals (E. albocollaris (n = 16), E.f. rufus (n = 14), E. collaris (n = 9), and purported hybrids from Andringitra (n = 21)). Diagnostic (d-loop and microsatellite 26) and private sites (all other genes) were found in all gene regions for E. albocollaris and E.f. rufus. Also, private sites were found for the purported hybrid population in two gene regions (d-loop and ceruloplasmin). When the putative hybrids were examined for diagnostic and private markers, 18 of 21 were found to contain markers from both E. albocollaris and E.f. rufus populations. The remaining three individuals were found to contain only markers for E. albocollaris. These results indicate that the population at Andringitra is a hybrid population between E. albocollaris and E.f. rufus.

Atelines are of particular interest to primate evolutionary studies because they converge with hominoids in postcranial anatomy, including the vertebral column. Currently, our understanding of ateline vertebral morphology is limited to mainly qualitative descriptions and functional interpretations based on general categories of positional behavior. Even less is known about the vertebrae of other platyrrhines. This study more closely examines vertebral form and function in atelines and cebines by combining direct field observations of axial postures and movements, assessments of spinal loading regimes, and a detailed vertebral morphometric analysis. Field observations (Corcovado, Costa Rica) on Ateles geoffroyi, Alouatta palliata, Cebus capucinus, and Saimiri oerstedii were quantified in conjunction with a morphometric analysis of ateline and cebine lumbar vertebrae. Hylobates was also included for comparison. Compared to Cebus and Saimiri, atelines engage more frequently in postures and locomotor behaviors that induce pronounced bending loads on the spine. All atelines share lumbar adaptations for resisting bending, including ventrodorsally elongated vertebral bodies and perpendicularly oriented transverse processes. Among atelines, lumbar region lengths and vertebral bodies are shortest in Ateles and Brachyteles, longest in Alouatta (resembling Cebus), and intermediate in Lagothrix. Compared to Cebus and all atelines, Saimiri has a relatively longer lumbar region, longer and less ventrodorsally expanded vertebral bodies, and more ventrally oriented transverse processes. These features accentuate bending loads, but increase the sagittal flexibility required for leaping. Vertebral convergence between hylobatids and atelines is more readily interpretable as a product of shared spinal loading patterns than shared positional behaviors.

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Primates, represented by 521 species, are distributed across 91 countries primarily in the Neotropic, Afrotropic, and Indo-Malayan realms. Primates inhabit a wide range of habitats and play critical roles in sustaining healthy ecosystems that benefit human and nonhuman communities. Approximately 68% of primate species are threatened with extinction because of global pressures to convert their habitats for agricultural production and the extraction of natural resources. Here, we review the scientific literature and conduct a spatial analysis to assess the significance of Indigenous Peoples’ lands in safeguarding primate biodiversity. We found that Indigenous Peoples’ lands account for 30% of the primate range, and 71% of primate species inhabit these lands. As their range on these lands increases, primate species are less likely to be classified as threatened or have declining populations. Safeguarding Indigenous Peoples’ lands, languages, and cultures represents our greatest chance to prevent the extinction of the world’s primates.

Climate and land cover change are driving a major reorganization of terrestrial biotic communities in tropical ecosystems. In an effort to understand how biodiversity patterns in the tropics will respond to individual and combined effects of these two drivers of environmental change, we use species distribution models (SDMs) calibrated for recent climate and land cover variables and projected to future scenarios to predict changes in diversity patterns in Madagascar. We collected occurrence records for 828 plant genera and 2186 plant species. We developed three scenarios, (i.e., climate only, land cover only and combined climate-land cover) based on recent and future climate and land cover variables. We used this modelling framework to investigate how the impacts of changes to climate and land cover influenced biodiversity across ecoregions and elevation bands. There were large-scale climate- and land cover-driven changes in plant biodiversity across Madagascar, including both losses and gains in diversity. The sharpest declines in biodiversity were projected for the eastern escarpment and high elevation ecosystems. Sharp declines in diversity were driven by the combined climate-land cover scenarios; however, there were subtle, region-specific differences in model outputs for each scenario, where certain regions experienced relatively higher species loss under climate or land cover only models. We strongly caution that predicted future gains in plant diversity will depend on the development and maintenance of dispersal pathways that connect current and future suitable habitats. The forecast for Madagascar’s plant diversity in the face of future environmental change is worrying: regional diversity will continue to decrease in response to the combined effects of climate and land cover change, with habitats such as ericoid thickets and eastern lowland and sub-humid forests particularly vulnerable into the future.