Primates in peril: the significance of Brazil, Madagascar, Indonesia and the Democratic Republic of the Congo for global primate conservation

Working and impacting local communities as establishing the start of a conservation initiative: American Society of Primatology conservation committee webinar

Nonhuman primate species currently face human-induced pressures and will continue to face them in the modern landscape. These pressures require conservation projects in primate habitat countries to aid in protection, preservation, and conservation. Though there are several examples of primate conservation projects, starting up an initiative can be a daunting task. The American Society of Primatology (ASP) Conservation Committee hosted a video webinar presenting on the first steps of developing, running and continuing a primate conservation program. Dr. Christopher Shaffer, Rahayu Oktaviani, and Dr. Jill Pruetz presented their early program experiences establishing wild primate conservation projects to educate primatologists around the world. The running themes of the presentations included establishing community, working locally, impacting locally and preparing for the future.

Effects of protected area coverage and research on conservation status of primates globally

Conducting conservation research and establishing protected areas (PAs) based on research results are critical to biodiversity conservation. However, the effect of research and PAs on conservation of threatened species has rarely been evaluated simultaneously. We collected data on PAs from 2000 for 2021 and determined the number of publications on global primates (published from 1950 to 2021) to assess the effect of PAs, research, and biological and socioeconomic factors on the current International Union for Conservation of Nature endangered status and change in status. We used the MCMCglmm package to conduct a phylogenetic comparative analysis to control the phylogenetic relationship of primate species. The status of 24.6% (82 of 333) of species assessed at least twice declined. Only the black lion tamarin (Leontopithecus chrysopygus) had an improved status. Species with status declines mostly occurred on the south coast of West Africa and in Madagascar. PAs covered 22.1% of each species' range. Forest loss in PAs (5.5%) was significantly lower than forest loss within 5 km outside PAs (13.8%), suggesting PAs effectively mitigated forest loss. Both the median number of total publications and conservation publications on critically endangered species were higher than those of other categories. Models showed that PA coverage and number of publications or conservation-focused publications were not related to current status or change in status over time. A decline in status was not related to creation of PAs or increase of research since the last assessment. Our results suggest that current PAs and research are not reversing the extinction crisis of global primates. Doing more conservation-oriented research, strengthening management of current PAs, and expanding PAs will be needed to protect primates globally.

Population assessment of the Endangered Kashmir Gray Langur (Semnopithecus ajax, Pocock 1928) using the double-observer method

Primates are among the most threatened taxa globally, therefore, there is a need to estimate and monitor their populations. Kashmir Gray Langur Semnopithecus ajax is an endangered species for which there is no population estimate. We used double-observer method to estimate its population size in the Kashmir region of North-Western Himalaya. We walked 1284 km across 31 survey blocks spanning all three divisions of Kashmir viz., North, Central, and South Kashmir, covering an area of 411 km2. We counted a minimum of 1367 individual langurs from 27 groups. The detection probability for observer 1 (0.719) and observer 2 (0.656) resulted in a population estimate of 1496 (95% confidence interval [CI] 1367-1899) across 30 groups (with a mean group size of 51), giving a density estimate of 3.64 (3.33-4.62) langurs/km². We found double-observer surveys to be suitable for the population estimation of langurs, and we make recommendations on how to effectively conduct primate surveys, especially in mountainous ecosystems. Our records extend the species distribution range beyond stated by the International Union for Conservation of Nature. Our findings also highlight that the Kashmir Himalaya is a stronghold of the species, where conservation efforts should focus.

Scientific activism to protect the world's primates and their environments from extinction: Introduction to the special issue

Nonhuman primates and their habitats are facing an impending extinction crisis. Approximately 69% of primate species are listed by the International Union for Conservation of Nature as threatened and 93% have declining populations. Human population growth (expected to reach 10.9 billion by the year 2100), the unsustainable demands of a small number of consumer nations for forest-risk commodities, deforestation and habitat conversion, the expansion of roads and rail networks, cattle ranching, the hunting and trapping of wild primate populations, and the potential spread of infectious diseases are among the primary drivers of primate population decline. Climate change will only exacerbate the current situation. The time to act to protect primate populations is now! In this special issue of the American Journal of Primatology, we present a series of commentaries, formulated as "Action Letters." These are designed to educate and inform primatologists, conservation biologists, wildlife ecologists, political leaders, and global citizens about the conservation challenges faced by particular primate taxa and particular world regions, and present examples of specific actions that one can take, individually and collectively, to promote the persistence of wild primate populations and environmental justice for local human populations and impacted ecological communities. As scientists, researchers, and educators, primatologists are in a unique position to lead local, national, and international efforts to protect biodiversity. In this special issue, we focus on primates of the Brazilian Amazon, lemurs of northeast Madagascar, Temminck's red colobus monkey (Piliocolobus badius temminckii), night monkeys (Aotus spp.), long-tailed macaques (Macaca fascicularis), the primate pet trade, and professional capacity building to foster conservation awareness and action. We encourage primatologists, regardless of their research focus, to engage in both advocacy and activism to protect wild primate populations worldwide.

Reproductive physiology with emphasis on endometrial cycles of woolly and uakari monkeys-A literature review

The ability of a species to withstand human impact depends on its life history characteristics, including social, ranging, and reproductive activity. The genera Lagothrix and Cacajao are more susceptible to anthropic action than small-sized primates due to their slower life histories, more restricted geographical ranges, and lower population densities. This narrative literature review aimed to gather scientific information available from the last 60 years on the reproductive biology of females of the genera Lagothrix and Cacajao. Most studies on the genus Lagothrix, mainly focused on L. lagothricha and L. l. poeppigii, present important advances on reproductive strategies, reproductive productivity, functional morphology and physiology, including seasonality, sexual cycle, gestation and fetal development in captive and free-living populations. Contrary, there is much less known about the reproductive biology of the genus Cacajao, with studies on free-living C. calvus and C. melanocephalus highlighting reproductive behavior, and basic description of the sexual cycle, gestation, and lactation. Unfortunately, the morphology of the female genital organs is only described in C. calvus, and there is still scarce information about the menstrual activity and the placenta. This literature review encourages primatologists, morphophysiologists, reproductive specialists, and ecologists to conduct comprehensive studies of these species to better understand the gaps in knowledge about reproduction, their relationship with their environment, including climatic and social variables. Understanding the integrative reproductive biology of these species will be a clue for improving the assessment of the resilience capacity of free-living populations and, consequently, establishing more appropriate management programs, and for the development of ex situ management techniques for the conservation of the species.

Retrospective study of the mortality of the Vieira's titi monkey (Plecturocebus vieirai) at the Sorocaba Zoo, Brazil

BACKGROUND

The Vieira's titi monkey (Plecturocebus vieirai) was recently described and characterized as endemic to Brazil. According to the IUCN red list, this species is classified as critically endangered (CR). At the date of the publication of this manuscript, there are no published data on the health aspects of this species.

METHODS

For this study, the necropsy, and histopathological data of the mortality of P. vieirai at Sorocaba Zoo (São Paulo, Brazil) were collected and analyzed.

RESULTS

Causes of death diagnosed included disorders of the urinary, gastrointestinal, immune, and circulatory systems.

CONCLUSIONS

This study provides information regarding the pathological conditions of P. vieirai and points to urinary and gastrointestinal diseases as the main causes of death in this species at Sorocaba Zoo. These results can help veterinarians who have this species under their care diagnose and deal with it more quickly, increasing the probability of survival.

Human activity and climate change accelerate the extinction risk to non-human primates in China

Human activity and climate change affect biodiversity and cause species range shifts, contractions, and expansions. Globally, human activities and climate change have emerged as persistent threats to biodiversity, leading to approximately 68% of the ~522 primate species being threatened with extinction. Here, we used habitat suitability models and integrated data on human population density, gross domestic product (GDP), road construction, the normalized difference vegetation index (NDVI), the location of protected areas (PAs), and climate change to predict potential changes in the distributional range and richness of 26 China's primate species. Our results indicate that both PAs and NDVI have a positive impact on primate distributions. With increasing anthropogenic pressure, species' ranges were restricted to areas of high vegetation cover and in PAs surrounded by buffer zones of 2.7-4.5 km and a core area of PAs at least 0.1-0.5 km from the closest edge of the PA. Areas with a GDP below the Chinese national average of 100,000 yuan were found to be ecologically vulnerable, and this had a negative impact on primate distributions. Changes in temperature and precipitation were also significant contributors to a reduction in the range of primate species. Under the expected influence of climate change over the next 30-50 years, we found that highly suitable habitat for primates will continue to decrease and species will be restricted to smaller and more peripheral parts of their current range. Areas of high primate diversity are expected to lose from 3 to 7 species. We recommend that immediate action be taken, including expanding China's National Park Program, the Ecological Conservation Redline Program, and the Natural Forest Protection Program, along with a stronger national policy promoting alternative/sustainable livelihoods for people in the local communities adjacent to primate ranges, to offset the detrimental effects of anthropogenic activities and climate change on primate survivorship.

Direct links between resource availability and activity budget better reveal ecological patterns of endangered Coimbra-Filho's titi monkey

Many primatological studies do not assess direct indexes of food availability to make inferences about behavioral strategies. We related the diet and behavior of a group of Callicebus coimbrai in northeastern Brazil to fruit availability indexes and compared this pattern between seasons (direct and indirect assessment of food availability) to assess whether direct and indirect approaches detect similar ecological patterns. We monitored the study group for 33 months (5 days/month) via scan sampling. The monthly availability of fruits and new leaves was recorded in phenological transects. Fruit availability varied across years based on fruit prevalence, and timing and duration of the abundant seasons. We did not find evidence of a time-minimizing strategy, since C. coimbrai did not change its activity levels according to food availability. However, the negative relationship between foraging and fruit availability indicates that C. coimbrai can compensate for the lower fruit availability by increasing the search for alternative food sources. Monthly fruit consumption was positively correlated to fruit availability and negatively related to the consumption of other food items. However, the behavioral and feeding profiles did not vary between seasons and were not related to rainfall levels. Primate studies should directly relate behavioral and feeding profiles to fruit availability indices, thus avoiding using seasons as proxies of food availability.

Use of wild vertebrates for consumption and bushmeat trade in Brazil: a review

BACKGROUND

Bushmeat is a resource exploited by thousands of people around the world, especially in tropical and neotropical regions, constituting an important source of protein and income. But what is known, so far, about the consumption and trade of wild vertebrate meat (hereinafter "bushmeat") in a megadiverse country like Brazil? This question was answered through a systematic survey of publications on the consumption and trade of wild vertebrate meat made in Brazil between 2011 and 2021.

METHODS

We selected 63 scientific articles available on "Google Scholar," "Science Direct," "Scopus," " Web of Science" and "Portal de Periódico da CAPES." The articles were categorized as: exclusive to (1) consumption or (2) bushmeat trade, totals of 54 and three articles, respectively; both (3) consumption and trade bushmeat, totaling six articles. We applied a nonparametric Spearman's correlation analysis to verify the association between the number of papers and the species richness of wild vertebrates cited for consumption by Brazilian state.

RESULTS

The results revealed that the publications were concentrated in the Northeast (36), North (26) and Southeast (1) regions, distributed across 16 states of the federation. These data reinforce the need for more researches in states and other regions of the country. Our research hypothesis was confirmed, since the richness of species cited for meat consumption was positively associated with the amount of work carried out by the states of the federation. We identified a total of 321 species of wild vertebrates mentioned in the categories involving the consumption of bushmeat. We had a greater bird species richness mentioned for consumption (170) to the detriment of mammals (107), reptiles (40) and amphibians (4). Furthermore, in the articles involving the bushmeat trade categories we had 57 species of vertebrates mentioned, with mammals being the most representative in terms of species richness (29), to the detriment of birds (20) and reptiles (8). These data reinforce that birds and mammals have been the groups most used both for consumption and trade in bushmeat in the country's regions, and it is necessary to mitigate the hunting exploitation of these groups. We recorded that socioeconomic, biological, environmental and sociocultural factors were the most cited predictors of the consumption and trade of bushmeat in the articles. We identified that the bushmeat trade chain is dynamic and ramified, made up of several actors, including specialized and diversified hunters, intermediaries, market sellers, market vendors, restaurant owners and final customers. Public markets and open-air fairs were the most cited places for buying and selling wild meat in commerce.

CONCLUSIONS

In general, our results indicate that we have made significant advances in publications on the consumption and trade of bushmeat in Brazil over the last few years. However, we highlight the need to better understand the patterns of consumption and trade of bushmeat in different regions of the country, as well as the factors associated with the dynamics of the trade chain and uses of wildlife by local communities. We emphasized that a multidimensional understanding of hunting activities is important to face socio-ecological problems and improve the conservation of target species which have continually been explored for uses by populations in different regions of the world.

Absence of Coronavirus RNA in Faecal Samples from Wild Primates in Gabon, Central Africa

Coronaviruses (CoVs, Coronaviridae) are a diverse group of viruses that infect mammals, birds, and fish. Seven CoVs infect humans, among which Severe Acute Respiratory Syndrome CoVs-1 and -2 and Middle East respiratory syndrome CoVs have shown how they can impact global health and the economy. Their spillover from bats-the natural reservoir-to humans has required intermediary hosts. Prevention requires that active surveillance be conducted on animals. Today, there is no data concerning the genetic diversity of CoVs naturally circulating in wild primates. This study aimed to screen wild great apes and mandrills in Gabon for CoVs. A total of 229 faecal samples of great apes and mandrills collected from 2009 to 2012 in forests and national parks were used for the detection of CoVs by nested PCR using primers targeting a conserved region of the RNA-dependent RNA polymerase. While all samples were negative, this lack of detection could be related to sample size, the transient nature of the infection, or because faecal samples are not suitable for detecting CoVs in primates. A longitudinal study should be performed and other non-invasive methods used to collect respiratory samples to better evaluate the circulation of CoVs in these primates.

Human-modified landscapes driving the global primate extinction crisis

The world's primates have been severely impacted in diverse and profound ways by anthropogenic pressures. Here, we evaluate the impact of various infrastructures and human-modified landscapes on spatial patterns of primate species richness, at both global and regional scales. We overlaid the International Union for the Conservation of Nature (IUCN) range maps of 520 primate species and applied a global 100 km2 grid. We used structural equation modeling and simultaneous autoregressive models to evaluate direct and indirect effects of six human-altered landscapes variables (i.e., human footprint [HFP], croplands [CROP], road density [ROAD], pasture lands [PAST], protected areas [PAs], and Indigenous Peoples' lands [IPLs]) on global primate species richness, threatened and non-threatened species, as well as on species with decreasing and non-decreasing populations. Two-thirds of all primate species are classified as threatened (i.e., Critically Endangered, Endangered, and Vulnerable), with ~86% experiencing population declines, and ~84% impacted by domestic or international trade. We found that the expansion of PAST, HFP, CROP, and road infrastructure had the most direct negative effects on primate richness. In contrast, forested habitat within IPLs and PAs was positively associated in safeguarding primate species diversity globally, with an even stronger effect at the regional level. Our results show that IPLs and PAs play a critical role in primate species conservation, helping to prevent their extinction; in contrast, HFP growth and expansion has a dramatically negative effect on primate species worldwide. Our findings support predictions that the continued negative impact of anthropogenic pressures on natural habitats may lead to a significant decline in global primate species richness, and likely, species extirpations. We advocate for stronger national and international policy frameworks promoting alternative/sustainable livelihoods and reducing persistent anthropogenic pressures to help mitigate the extinction risk of the world's primate species.

Molecular detection and genetic characterization of Ehrlichia canis and Ehrlichia sp. in neotropical primates from Brazil

The Anaplasmataceae family includes obligate, arthropod-transmitted intracellular bacteria that can be zoonotic and potentially fatal. Studies focusing on the interaction between neotropical primates and the agents of this family are scarce. The present study aimed to identify agents of the Anaplasmataceae family in the whole blood of free-living and captive neotropical primates in the State of Mato Grosso, Central-West Brazil. Thirty-eight samples of six nonhuman primate (NHP) species were collected in seven municipalities and analysed through polymerase chain reaction (PCR), nucleotide sequencing, and phylogenetic analysis of the dsb, groEL, 16S rRNA, and gltA genes. DNA fragments similar to those of Ehrlichia canis were detected in Sapajus apella and Ehrlichia chaffeensis from Mico melanurus. The sequences generated in this study and homologous sequences retrieved from GenBank® were used for phylogenetic analyses to characterize the Ehrlichial agents detected in NHPs. The agents were then grouped into clades corresponding to different isolates from the NHP species. In addition, an Anaplasma sp. closely related to Anaplasma marginale was identified in two S. apella individuals. These findings shed light on the susceptibility of neotropical NHPs to Anaplasmataceae agents. These bacteria are known to be transmitted by ticks, which can also serve as possible sources of infection for other animals, including humans.

Both Diet and Sociality Affect Primate Brain-Size Evolution

Increased brain size in humans and other primates is hypothesized to confer cognitive benefits but brings costs associated with growing and maintaining energetically expensive neural tissue. Previous studies have argued that changes in either diet or levels of sociality led to shifts in brain size, but results were equivocal. Here we test these hypotheses using phylogenetic comparative methods designed to jointly account for and estimate the effects of adaptation and phylogeny. Using the largest current sample of primate brain and body sizes with observation error, complemented by newly compiled diet and sociality data, we show that both diet and sociality have influenced the evolution of brain size. Shifting from simple to more complex levels of sociality resulted in relatively larger brains, while shifting to a more folivorous diet led to relatively smaller brains. While our results support the role of sociality, they modify a range of ecological hypotheses centered on the importance of frugivory, and instead indicate that digestive costs associated with increased folivory may have resulted in relatively smaller brains. [adaptation; allometry; bayou; evolutionary trend; energetic constraints; phylogenetic comparative methods; primate brain size; Slouch; social-brain hypothesis.].

Road Infrastructure and Primate Conservation: Introducing the Global Primate Roadkill Database

As road infrastructure networks rapidly expand globally, especially in the tropics, previously continuous habitats are being fragmented, resulting in more frequent wildlife-vehicle collisions (WVC). Primates are widespread throughout many sub-/tropical countries, and as their habitats are fragmented, they are increasingly at risk of WVC. We created the Global Primate Roadkill Database (GPRD), the largest available standardized database of primate roadkill incidents. We obtained data from published papers, un-published and citizen science databases, anecdotal reports, news reports, and social media posts. Here, we describe the collection methods for the GPRD and present the most up-to-date version of the database in full. For each primate roadkill incident, we recorded the species killed, the exact location, and the year and month the roadkill was observed. At the time of publication, the GPRD includes 2862 individual primate roadkill records from 41 countries. As primates range in more than twice as many countries, the absence of data from these countries is not necessarily indicative of a lack of primate vehicular collisions. Given the value of these data for addressing both local and global research questions, we encourage conservationists and citizen scientists to contribute to the GPRD so that, together, we can better understand the impact road infrastructure has on primates and evaluate measures which may help mitigate risk-prone areas or species.

Influence of landscape structure on previous exposure to Leptospira spp. and Brucella abortus in free-living neotropical primates from southern Brazil

The environments in which neotropical primates live have been undergoing an intense fragmentation process, constituting a major threat to the species' survival and causing resource scarcity, social isolation, and difficulty in dispersal, leaving populations increasingly vulnerable. Moreover, the proximity of wild environments to anthropized landscapes can change the dynamics of pathogens and the parasite-host-environment relationship, creating conditions that favor exposure to different pathogens. To investigate the previous exposure of free-living primates in Rio Grande do Sul State (RS), southern Brazil, to the bacterial agents Leptospira spp. and Brucella abortus, we investigated agglutinating antibodies against 23 serovars of Leptospira spp. using the microscopic agglutination test and B. abortus acidified antigen test in primate serum samples; 101 samples from primates captured between 2002 and 2016 in different forest fragments were used: 63 Alouatta caraya, 36 Alouatta guariba clamitans, and 02 Sapajus nigritus cucullatus. In addition, the forest remnants where the primates were sampled were characterized in a multiscale approach in radii ranging from 200 to 1400 m to investigate the potential relationship of previous exposure to the agent with the elements that make up the landscape structure. The serological investigation indicated the presence of antibodies for at least one of the 23 serovars of Leptospira spp. in 36.6% (37/101) of the samples analyzed, with titers ranging from 100 to 1600. The most observed serovars were Panama (17.8%), Ballum (5.9%), Butembo (5.9%), Canicola (5.9%), Hardjo (4.9%), and Tarassovi (3.9%); no samples were seropositive for Brucella abortus. Decreased forest cover and edge density were the landscape factors that had a significant relationship with Leptospira spp. exposure, indicating that habitat fragmentation may influence contact with the pathogen. The data generated in this study demonstrate the importance of understanding how changes in landscape structure affect exposure to pathogenic microorganisms of zoonotic relevance. Hence, improving epidemiological research and understanding primates' ecological role in these settings can help improve environmental surveillance and conservation strategies for primate populations in different landscapes.

Primates facing climate crisis in a tropical forest hotspot will lose climatic suitable geographical range

Global climate changes affect biodiversity and cause species distribution shifts, contractions, and expansions. Climate change and disease are emerging threats to primates, and approximately one-quarter of primates' ranges have temperatures over historical ones. How will climate changes influence Atlantic Forest primate ranges? We used habitat suitability models and measured potential changes in area and distributions shifts. Climate change expected in 2100 may change the distribution area of Atlantic Forest primates. Fourteen species (74%) are predicted to lose more than 50% of their distribution, and nine species (47%) are predicted to lose more than 75% of their distribution. The balance was negative, indicating a potential future loss, and the strength of the reduction in the distribution is related to the severity of climate change (SSP scenarios). Directional shifts were detected to the south. The projected mean centroid latitudinal shift is ~ 51 km to the south for 2100 SSP5-8.5 scenario. The possibility of dispersal will depend on suitable routes and landscape configuration. Greenhouse gas emissions should be urgently reduced. Our results also emphasize that no more forest loss is acceptable in Atlantic Forest, and restoration, canopy bridges, friendly agroecosystems, and monitoring of infrastructure projects are urgent to enable dealing with climate change.

First Molecular Identification of Trypanosomes and Absence of Babesia sp. DNA in Faeces of Non-Human Primates in the Ecuadorian Amazon

Trypanosomes are a group of pathogens distributed in the continents of Africa, America, Asia and Europe, and they affect all vertebrates including the neotropical primate group. Information about the trypanosome's diversity, phylogeny, ecology and pathology in non-human primates (NHPs) from the neotropical region is scarce. The objective of the study was to identify Trypanosoma and Babesia molecularly in NHPs under the phylogenetic species concept. We extracted DNA from a total of 76 faecal samples collected between 2019 and 2021, from a total of 11 non-human primate species of which 46 are from captive NHPs and 30 are free-living NHPs in the Western Amazon region of Ecuador. We did not detect DNA of Babesia sp. by polymerase chain reaction test in any of the faecal samples. However, the nested-PCR-based method revealed Trypanosoma parasites by ITS gene amplification in two faecal samples; one for the species Leontocebus lagonotus (from the captive population) and a second one for Cebus albifrons (from the free-ranging population). Maximum parsimony and likelihood methods with the Kimura2+G+I model inferred the evolutionary history of the two records, which showed an evolutionary relationship with the genus Trypanosoma. Two sequences are monophyletic with Trypanosoma. However, the number of sequences available in GenBank for their species identification is limited. The two samples present different molecular identifications and evolutionary origins in the tree topology. We are most likely referring to two different species, and two different localities of infection. We suggest that health management protocols should be implemented to prevent the transmission of blood-borne pathogens such as Trypanosoma sp. among captive populations. In addition, these protocols also protect the personnel of wildlife rehabilitation centers working in close proximity to NHPs and vice versa.

Establishing the relationship between non-human primates and mangrove forests at the global, national, and local scales

Global and spatially explicit information about the interaction between habitat and wildlife species is critical to enhancing conservation efforts. Despite the recognized importance of mangrove forests to non-human primates, the relationship between the two lacks understanding. To counter this, we created the MangPrim-21 database to map and measure the locations of interactions between all non-human primates and all mangrove forests globally. We report our findings across the global, national, and local scales for all inventoried non-human primates and all inventoried mangrove forests. Globally, we find that half of all non-primates potentially use mangrove forests, and more than half of the global mangrove forest falls within the delineated range of at least one non-human primate species. Nationally, we find that Indonesia, Madagascar, Brazil, Cameroon, and Malaysia likely have the most non-human primate and mangrove forest interactions. At the subnational level, we find that several discrete locations in Kalimantan are critical to both mangrove forests and non-human primates. The MangPrim-21 database provides a globally consistent and locally applicable database of non-human primate and mangrove forest interactions. The results presented have broader implications for non-human primate and mangrove conservation and global actions to protect both. Additionally, our results raise questions about the idea that non-human primates primarily use mangrove forests as a refuge from human encroachment and habitat degradation.

Using population surveys and models to reassess the conservation status of an endemic Amazonian titi monkey in a deforestation hotspot

Assessing the conservation status of species is essential for implementing appropriate conservation measures. A lack of evidence of threats, rather than showing an absence of impacts, could reflect a lack of studies on how human activities could result in species population declines. The range of Prince Bernhard's titi monkey Plecturocebus bernhardi is restricted to the Arc of Deforestation, a deforestation hotspot in south-eastern Amazonia. Despite this, it is categorized as Least Concern on the IUCN Red List. To reassess the conservation status of P. bernhardi, we carried out surveys during 2015–2017 to delimit the geographical distribution of the species and estimate its population density and abundance. We then used spatial predictive modelling to examine future habitat and population loss within its range. Plecturocebus bernhardi occurs over an area of 131,295 km2. Its mean group size was 2.8 individuals/group and its density 10.8 individuals/km2 and 3.8 groups/km2. Habitat loss was estimated to be 58,365 km2 (32.3% of its current range) over the next 24 years (three P. bernhardi generations) under a conservative governance model of deforestation and 105,289 km2 (58.3%) under a business-as-usual model. These numbers indicate that P. bernhardi is threatened and should be categorized as Vulnerable, at least, using the IUCN Red List criteria. We recommend the reassessment of other Least Concern primate species from the Arc of Deforestation using a similar approach.

Signatures of adaptive evolution in platyrrhine primate genomes

The platyrrhine family Cebidae (capuchin and squirrel monkeys) exhibit among the largest primate encephalization quotients. Each cebid lineage is also characterized by notable lineage-specific traits, with capuchins showing striking similarities to Hominidae such as high sensorimotor intelligence with tool use, advanced cognitive abilities, and behavioral flexibility. Here, we take a comparative genomics approach, performing genome-wide tests for positive selection across five cebid branches, to gain insight into major periods of cebid adaptive evolution. We uncover candidate targets of selection across cebid evolutionary history that may underlie the emergence of lineage-specific traits. Our analyses highlight shifting and sustained selective pressures on genes related to brain development, longevity, reproduction, and morphology, including evidence for cumulative and diversifying neurobiological adaptations across cebid evolution. In addition to generating a high-quality reference genome assembly for robust capuchins, our results lend to a better understanding of the adaptive diversification of this distinctive primate clade.

Distribution and diversity of primates and threats to their survival in the Awi Zone, northwestern Ethiopia

Habitat loss and fragmentation affect the diversity and distribution of primates in a human-modified landscape. Ethiopia has a high diversity of primates, but increasing human pressure has negatively impacted their distribution and abundance across the country, primarily due to deforestation. To date, the diversity and distribution of primate species are poorly known in northwestern Ethiopia. From October 2020 until September 2021, we assessed the diversity and distribution of primate species in 26 forest patches in the Awi Zone, Northwestern Ethiopia using line transect surveys, and we examined the potential conservation threats to the survival of these taxa. Across transects, we encountered 459 groups of four primate taxa: olive baboons (Papio anubis), grivet monkeys (Chlorocebus aethiops), Boutourlini's blue monkeys (Cercopithecus mitis boutourlinii), and black-and-white colobus monkeys (Colobus guereza spp. guereza). The latter two are endemic to Ethiopia. We observed black-and-white colobus monkeys in all surveyed forest patches, while we observed Boutourlini's blue monkeys in 18 patches. Black-and-white colobus monkeys were the most frequently observed (n = 325 sighting; relative encounter frequency = 70.8%), while grivet monkeys (Chlorocebus aethiops) were the least (n = 34 sighting; relative encounter frequency = 7.4%) in the region. Similarly, the relative encounter frequency of olive baboons was 9.2% (n = 42 sighting). The overall mean group size for each species was: Boutourlini's blue monkeys (26.1 individuals), black-and-white colobus monkeys (8.8 individuals), grivet monkeys (34.1 individuals), and olive baboons (41.4 individuals). We identified agricultural expansions, exotic tree plantations, deforestations, firewood collections, livestock grazing, and killings over their crop-feeding behaviors as the main threats to primates and their habitats in the region. This study provides crucial information on an area likely to support primate species that we know very little about. Assigning protected connecting forest patches should be an urgent priority for the conservation of the primates in this region.

Demographic changes in an Atlantic Forest primate community following a yellow fever outbreak

We investigated demographic changes in three primate species (Alouatta guariba, Sapajus nigritus, and Callithrix flaviceps) at the Reserva Particular do Patrimônio Natural-Feliciano Miguel Abdala, Caratinga, Minas Gerais, Brazil, following a yellow fever outbreak (YFO) by comparing their population sizes before (2015) and after the outbreak (2017-2018), and by monitoring the size, composition, and reproductive status of groups from 2017 to 2021. Comparisons of pre- and post-YFO census data indicate the A. guariba population declined by 86.6%, from an estimated minimum of 522 individuals to 70 individuals. However, by October 2021, the population had grown to at least 86 individuals, with an adult sex ratio (N = 53) that was female-biased (0.61). Eleven of the 13 groups being monitored systematically were reproductively active with high survivorship to 12 months of age. S. nigritus declined by 40%, from 377 to 226 individuals. The sex ratio of 33 adult S. nigritus is also female-biased (0.71), and at least 8 of 15 groups being monitored are reproductively active. C. flaviceps declined by 80%, from 85 individuals to the 15-17 individuals observed from 2017 to 2021. The female-biased adult sex ratio and presence of infants and juveniles in the A. guariba and S. nigritus groups are encouraging signs, but there is still great concern, especially for C. flaviceps. Continued monitoring of the demographics of these primates is needed as their persistence appears to still be at risk.

Anthropogenic Disturbance Impacts Gut Microbiome Homeostasis in a Malagasy Primate

Increasing anthropogenic disturbances in Madagascar are exerting constrains on endemic Malagasy lemurs and their habitats, with possible effects on their health and survival. An important component of health is the gut microbiome, which might be disrupted by various stressors associated with environmental change. We have studied the gut microbiome of gray-brown mouse lemurs (Microcebus griseorufus), one of the smallest Malagasy primates and an important model of the convergent evolution of diseases. We sampled two sites: one situated in a national park and the other consisting of a more disturbed site around human settlement. We found that more intense anthropogenic disturbances indeed disrupted the gut microbiome of this lemur species marked by a reduction in bacterial diversity and a shift in microbial community composition. Interestingly, we noted a decrease in beneficial bacteria (i.e., members of the Bacteroidaceae family) together with a slight increase in disease-associated bacteria (i.e., members of the Veillonellaceae family), and alterations in microbial metabolic functions. Because of the crucial services provided by the microbiome to pathogen resistance and host health, such negative alterations in the gut microbiome of mouse lemurs inhabiting anthropogenically disturbed habitats might render them susceptible to diseases and ultimately affecting their survival in the shrinking biodiversity seen in Madagascar. Gut microbiome analyses might thus serve as an early warning signal for pending threats to lemur populations.

Effect of Anthropogenic Activities on the Population of Moor Macaques (Macaca maura) in South Sulawesi, Indonesia

Forest loss due to anthropogenic activities is one of the main causes of plant and animal species decline. Studying the species’ population status (i.e., density, abundance, and geographic distribution) on a regular basis is one of the main tools to assess the effect of anthropogenic activities on wildlife, to monitor population dynamics and to intervene with effective conservation strategies when the population of an endangered species declines. On Sulawesi Island, Indonesia, anthropogenic activities, such as agriculture, are decreasing the remaining natural habitats available for several endemic and endangered species. The effect of this forest loss on the threatened moor macaques (Macaca maura) in South Sulawesi is unknown, and data on the population status of this species are needed to design effective conservation strategies. To assess the population status of the moor macaques, we walked linear transects (N = 29, survey effort = 114 km) at six sites between November 2019 and March 2020 to estimate macaque population density and encounter rate. We tested the effect of anthropogenic activities on macaque encounter rate. Our global density estimate (24 individuals/km2) was lower than the overall estimate from the most detailed survey conducted on this species, which covered its whole geographic distribution (36.1 individuals/km2). However, these results should be interpreted with caution because the previous density estimate falls within the confidence intervals of our estimate. Furthermore, we found regional declines in moor macaque encounter rates in at least two sites compared with previous studies. We found a high presence of anthropogenic activity in the forests inhabited by macaques. Moor macaques were less abundant in open areas with no forest (i.e., clear cuttings) than in forested areas, and in the presence of nonspecies-specific hunting traps (i.e., wire-loop traps). Moreover, moor macaques were more abundant in areas with a higher presence of humans and domestic animals. Overall, our data suggest that the population of this species may be declining in certain regions but further surveys are needed to corroborate whether this is occurring across the entire geographic distribution.

Risk perceptions and behaviors of actors in the wild animal value chain in Kinshasa, Democratic Republic of Congo

In the Democratic Republic of Congo (DRC) which contains the greatest area of the second largest rainforest on Earth, people have long been connected to the forest for subsistence and livelihood from wild animals and bushmeat. This qualitative study sought to characterize the bushmeat movement—from hunting wild animals to market sale—and the roles of participants in the animal value chain, as well as their beliefs surrounding zoonotic disease and occupational risk. Actors in in eight bushmeat markets and two ports in Kinshasa, DRC completed semi-structured interviews between 2016 and 2018 in which they expressed belief in transmission of illness from domestic animals to humans, but not from wild animals to humans. Wild animals were viewed as pure and natural, in contrast to domestic animals which were considered tainted by human interference. Participants reported cutting themselves during the process of butchering yet did not consider butchering bushmeat to be a risky activity. Instead, they adopted safety practices learned over time from butchering experts and taught themselves how to butcher in a fashion that reduced the frequency of cutting. In general, butcherers rejected the idea of personal protective equipment use. Port markets were identified as important access points for meat coming from the Congo river and plane transport was identified as important for fresh and live meat coming from Équateur province. Most participants reported having heard about Ebola, but their mistrust in government messaging privileged a word-of-mouth story of witchcraft to be propagated about Ebola’s origins. It is critical to better understand how public health messaging about outbreaks can successfully reach high risk communities, and to develop creative risk mitigation strategies for populations in regular contact with animal blood and body fluids. In this paper, we offer suggestions for formal and informal trusted channels through which health messages surrounding zoonotic risk could be conveyed to high-risk populations in Kinshasa.

Identifying and mitigating the impacts on primates of transportation and service corridors

Most primate populations are declining; 60% of species face extinction. The expansion of transportation and service corridors (T&S) (i.e., roads and railways and utility and service lines) poses a significant yet underappreciated threat. With the development of T&S corridors predicted to increase across primates' ranges, it is necessary to understand the current extent of its impacts on primates, the available options to mitigate these effectively, and recognize research and knowledge gaps. By employing a systematic search approach to identify literature that described the relationship between primates and T&S corridors, we extracted information from 327 studies published between 1980 and 2020. Our results revealed that 218 species and subspecies across 62 genera are affected, significantly more than the 92 listed by the IUCN Red List of Threatened Species. The majority of studies took place in Asia (45%), followed by mainland Africa (31%), the Neotropics (22%), and Madagascar (2%). Brazil, Indonesia, Equatorial Guinea, Vietnam, and Madagascar contained the greatest number of affected primate species. Asia featured the highest number of species affected by roads, electrical transmission lines, and pipelines and the only studies addressing the impact of rail and aerial tramways on primates. The impact of seismic lines only emerged in the literature from Africa and the Neotropics. Impacts are diverse and multifaceted, for example, animal-vehicle collisions, electrocutions, habitat loss and fragmentation, impeded movement and genetic exchange, behavioral changes, exposure to pollution, and mortality associated with hunting. Although several mitigation measures were recommended, only 41% of studies focused on their implementation, whereas only 29% evaluated their effectiveness. Finally, there was a clear bias in the species and regions benefiting from research on this topic. We recommend that government and conservation bodies recognize T&S corridors as a serious and mounting threat to primates and that further research in this area is encouraged.

Determinants of habitat occupancy and spatial segregation of primates in the central Western Ghats, India

Primates are among the globally imperiled fauna requiring urgent conservation interventions to protect their habitat. Information on species distribution and factors influencing it are vital to species management and habitat protection. In this study, we assessed habitat occupancy of the lion-tailed macaque (Macaca silenus), bonnet macaque (M. radiata), and black-footed gray langur (Semnopithecus hypoleucos) that occur in the Kudremukh Wildlife Division, a large protected area network in the central Western Ghats. We examined the influence of habitat variables on the occupancy probability of these primates. We carried out four temporally replicated detection/non-detection surveys to assess detection probability and site occupancy of the primate species. We surveyed 244 sites of 5 Km², with each site surveyed for 4 days, to assess detection probability and site occupancy. Among the three species, the langur had the highest habitat occupancy estimate (0.66 ± 0.05_SE) and the lion-tailed macaque had the lowest estimate (0.28 ± 0.08_SE). The habitat occupancy estimate for the bonnet macaque was (0.56 ± 0.05_SE)_. Wet and semi-evergreen forest cover and mean elevation positively influenced the lion-tailed macaque's occurrence. Covariates influencing bonnet macaque's occurrence were plantations, semi-evergreen and moist deciduous forests, and non-forest areas. Mean elevation negatively affected its occurrence. Wet evergreen forests and plantations positively influenced the occurrence of the langur. We examined spatial segregation between the species based on their site occupancy. Pairwise comparisons revealed a significant negative association between the bonnet macaque and the other two primates. However, we found a significant positive association between the lion-tailed macaque and the langur. We discuss these results and their implications for conservation of primates in the region. Given the cost-effectiveness of carrying out surveys at large spatial scales, we recommend occupancy surveys for future surveys of forest primates.

Population size and habitat preference of the Omo River guereza (Colobus guereza guereza) in a multi-habitat matrix in the central highlands of Ethiopia

Given the current rate of habitat degradation and loss in the tropics, data on primate population densities and habitat use are indispensable for assessing conservation status and designing feasible management plans for primates. The Omo River guereza (Colobus guereza guereza) is a subspecies of the eastern black-and-white colobus monkey endemic to the western Rift Valley forests of Ethiopia. Their restricted distribution along with habitat loss and hunting within their range render them vulnerable to local extirpation and extinction. Furthermore, there are no published data available on the population status and habitat use patterns of the Omo River guereza. We therefore aimed to assess the population size of Omo River guerezas in different habitats (Erica-Juniperus mixed forest, mixed plantation forest, undisturbed natural forest, disturbed natural forest) using transect surveys at Wof-Washa Natural State Forest (WWNSF) in central Ethiopia. Our surveys covered a cumulative distance of 88.5 km in four different habitats, during which we recorded a total of 140 Omo River guereza groups. The average group density was 14.3 groups/km², average individual density was 94.4 individuals/km², and we estimated the total population size within WWNSF to be 2549 individuals. The sex ratio of the population was split evenly between males and females, though the age classes skewed strongly towards adults. Of the habitats surveyed, the highest group encounter rate (1.83 groups/km) occurred in the disturbed natural forest. However, the highest individual density (110.1 individuals/km²) was recorded in undisturbed natural forest. Still, sizable densities (group and individual) were recorded in three of the disturbed habitats (disturbed natural forest, mixed plantation forest, and to a lesser extent Erica-Juniperus mixed forest). Our study offers the first baseline information with which to compare future population density estimates and habitat use in the range of Omo River guerezas.

Social-Ecological Interactions Influencing Primate Harvest: Insights From Madagascar

Globally, non-human primates face mounting threats due to unsustainable harvest by humans. There is a need to better understand the diverse drivers of primate harvest and the complex social-ecological interactions influencing harvest in shared human-primate systems. Here, we take an interdisciplinary, systems approach to assess how complex interactions among primate biological and ecological characteristics and human social factors affect primate harvest. We apply our approach through a review and synthesis of the literature on lemur harvest in Madagascar, a country with one of the highest primate species richness in the world coupled with high rates of threatened primate species and populations in decline. We identify social and ecological factors affecting primate harvest, including the characteristics of lemurs that may make them vulnerable to harvest by humans; factors describing human motivations for (or deterrents to) harvest; and political and governance factors related to power and accessibility. We then discuss social-ecological interactions that emerge from: (1) the prevalence of informal institutions (e.g., cultural taboos), (2) adoption of human predatory strategies, (3) synergies with habitat use and habitat loss, and (4) interactions among regional- and local-scale factors (multi-level interactions). Our results illustrate that social-ecological interactions influencing lemur harvest in Madagascar are complex and context-specific, while influenced by a combination of interactions between species-specific characteristics and human social factors. These context-specific interactions may be also influenced by local-level cultural practices, land use change, and effects from regional-level social complexities such as political upheaval and food insecurity. We conclude by discussing the importance of identifying and explicitly accounting for nuances in underlying social-ecological systems and putting forth ideas for future research on primate harvest in shared human-primate systems, including research on social-ecological feedbacks and the application of Routine Activities Theory.

Noninvasive Technologies for Primate Conservation in the 21st Century

Observing and quantifying primate behavior in the wild is challenging. Human presence affects primate behavior and habituation of new, especially terrestrial, individuals is a time-intensive process that carries with it ethical and health concerns, especially during the recent pandemic when primates are at even greater risk than usual. As a result, wildlife researchers, including primatologists, have increasingly turned to new technologies to answer questions and provide important data related to primate conservation. Tools and methods should be chosen carefully to maximize and improve the data that will be used to answer the research questions. We review here the role of four indirect methods—camera traps, acoustic monitoring, drones, and portable field labs—and improvements in machine learning that offer rapid, reliable means of combing through large datasets that these methods generate. We describe key applications and limitations of each tool in primate conservation, and where we anticipate primate conservation technology moving forward in the coming years.

Dramatic decline in a titi monkey population after the 2016-2018 sylvatic yellow fever outbreak in Brazil

Platyrrhini are highly vulnerable to the yellow fever (YF) virus. From 2016 to 2018, the Atlantic Forest of southeast Brazil faced its worst sylvatic YF outbreak in about a century, thought to have killed thousands of primates. It is essential to assess the impact of this epidemic on threatened primate assemblages to design effective conservation strategies. In this study, we assessed the impact of the 2016-2018 YF outbreak on a geographically isolated population of Near Threatened black-fronted titi monkeys (Callicebus nigrifrons) in two Atlantic Forest patches of the Santuário do Caraça, MG, Brazil. Extensive preoutbreak monitoring, conducted between 2008 and 2016, revealed that the home range and group sizes of the population remained stable. In 2016, the population size was estimated at 53-57 individuals in 11-12 groups. We conducted monitoring and playback surveys in 2019 and found that the population had decreased by 68% in one forest patch and completely vanished in the other, resulting in a combined decline of 80%. We discuss this severe loss of a previously stable population and conclude that it was highly likely caused by the YF outbreak. The remaining population is at risk of disappearing completely because of its small size and geographic isolation. A systematic population surveys of C. nigrifrons, along other sensible Platyrrhini species, is needed to re-evaluate their current conservation status.

Why do people visit primate tourism sites? Investigating macaque tourism in Japan and Indonesia

Primates are popular species in wildlife tourism contexts and provide economic benefits to habitat countries where primate-based tourism activities are a part of the country's tourism economy. Primate tourism runs a broad gamut from safari-like expeditions within remote primate habitats to designated monkey parks and incidental primate tourism. In most forms of primate tourism, primate ecology and behaviour are directly influenced by humans, making these interfaces particularly relevant for examination using the lens of ethnoprimatology. While several studies have assessed the impact of tourism on primates, little is known about people's motivations for observing monkeys for recreational purposes. Here we present two case studies-the Jigokudani Monkey Park, Japan, and the Telaga Warna Nature Recreational Park, Indonesia-where we provide quantitative assessments of people's motivations for visiting managed (monkey parks) and unmanaged (incidental) monkey tourism sites. We further show that management regimes, socio-demographic attributes, previous experience of interactions with macaques, and feeding them play a role in people's desire to visit macaque tourism sites. In Japan, those who had interacted with macaques before were more likely to visit the park to observe macaques clearly and at close quarters. In contrast, respondents in Indonesia were more interested in the recreational opportunities offered by the nature reserve rather than in macaques. However, here too, people who had interacted with macaques earlier were more likely to visit incidental macaque tourist sites for the sole purpose of viewing or interacting with macaques. Almost 50% of the Japanese respondents visited the monkey park due to personal inclinations, while less than 14% of people in Indonesia visited the park of their own volition. Also, over 57% of the Japanese respondents said that visiting monkey parks helped them gain a better understanding of macaque behaviour, whereas only about 26% respondents said likewise in Indonesia. Unlike the Japanese respondents, most of the Indonesian respondents engaged in feeding macaques. These findings suggest that management regimes as well as socio-demographic attributes may influence people's motivations to visit macaque tourism sites.

Species distribution and conservation assessment of the black-headed night monkey (Aotus nigriceps): a species of Least Concern that faces widespread anthropogenic threats

Deforestation rates in the Brazilian Amazon have been steadily increasing since 2007. Recent government policy, the projected growth of agriculture, and the expansion of the cattle industry are expected to further pressure primates within the Amazon basin. In this study, we examined the anthropogenic impact on the widely distributed black-headed night monkey, Aotus nigriceps, whose distribution and population status have yet to be assessed. We (1) modeled potential species distribution in A. nigriceps, (2) estimated the impact of habitat loss on population trends, and (3) highlight landscape-based conservation actions that maximize the potential for their long-term sustainability. We found the black-headed night monkey to be restricted by several biotic and environmental factors including forest cover, isothermality, precipitation, temperature, and elevation. Over the last two decades, over 132,908 km² of tree cover (18%) has been lost within their currently recognized range based on satellite imagery. Based on a balance training omission, predicted area, and threshold values (BPTP), suitable habitat was only 67% (1,069,948 km²) of their hypothesized range, a loss of 16.5% from 2000, with just nearly a third of suitable habitat currently within protected areas. Over the last two decades, an estimated minimum 1.6 million individuals have been lost due to loss of suitable habitat. Projected deforestation rates equate to an additional loss of 94,458 km² of suitable habitat over the next decade. Although classified as a species of Least Concern, we suggest that A. nigriceps may likely be more at risk than previously described. The future impact of the continued expansion of monoculture crops, cattle ranching, and wildfires is still unknown. However, we outline several steps to ensure the long-term viability of this nocturnal primate and other sympatric species throughout the Amazon Basin.