Professor Giuseppe Donati

Conservation funding is currently limited; cost-effective conservation solutions are essential. We suggest that the thousands of field stations worldwide can play key roles at the frontline of biodiversity conservation and have high intrinsic value. We assessed field stations’ conservation return on investment and explored the impact of COVID-19. We surveyed leaders of field stations across tropical regions that host primate research; 157 field stations in 56 countries responded. Respondents reported improved habitat quality and reduced hunting rates at over 80% of field stations and lower operational costs per km2 than protected areas, yet half of those surveyed have less funding now than in 2019. Spatial analyses support field station presence as reducing deforestation. These “earth observatories” provide a high return on investment; we advocate for increased support of field station programs and for governments to support their vital conservation efforts by investing accordingly

Post-release monitoring is important to improve translocation success because it provides an opportunity to identify factors relevant to the survival of local populations. We studied a population of the endangered collared brown lemur (Eulemur collaris) translocated from a degraded forest fragment to a nearby littoral forest within the Mandena Conservation Area in southeast Madagascar from 2000–2011. We compared genetic surveys of mitochondrial and nuclear markers with the genetic profile of nearby populations to examine the dispersal capacity of the collared brown lemur. We also performed a landscape analysis to assess changes in connectivity between forest fragments. There was a fluctuating trend characterized by a phase of demographic and genetic stability shortly after translocation, followed by an increase in genetic diversity coinciding with a population decrease and a gradual recovery of initial conditions. These results demonstrated the ability of the collared brown lemur to disperse through unfavorable landscapes and to recover after translocation. Our study revealed the importance of monitoring translocated populations over time using a multidisciplinary approach.

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.

Edge effects result from interactions between adjacent habitats, which can modify abiotic and biotic conditions and produce various negative effects on biodiversity. Given the high degree of forest fragmentation in Madagascar, understanding lemur responses to edges is a conservation priority. We aim to determine the depth of edge influence in a continuous low-land rainforest of south-eastern Madagascar and identify the response of six lemur species. We surveyed lemur abundance along nine 1 km transects from May 2015 to July 2016 totaling 112.2 km of survey effort during the day and 88.5 km at night. We characterized the habitat structure via 33 plots centered along the line transects. We used Generalized Additive Models and Generalized Linear Models to test the effect of distance from the forest edge on vegetation parameters and animal encounter rates. Edge effect on the vegetation structure can be detected up to around 100 m in terms of tree diversity and density. We found a negative edge response for Madame Fleurette’s sportive lemurs (Lepilemur fleuretae) and collared brown lemurs (Eulemur collaris), and a positive edge response for Anosy mouse lemurs (Microcebus tanosi), Southern bamboo lemurs (Hapalemur meridionalis) and Southern woolly lemurs (Avahi meridionalis). Since around half of the forested areas in Madagascar are within 100 m of forest edge, taking into account edge effect is vital when producing estimates of population sizes and informing conservation management.

Among mammals, the order Primates is exceptional in having a high taxonomic richness in which the taxa are arboreal, semiterrestrial, or terrestrial. Although habitual terrestriality is pervasive among the apes and African and Asian monkeys (catarrhines), it is largely absent among monkeys of the Americas (platyrrhines), as well as galagos, lemurs, and lorises (strepsirrhines), which are mostly arboreal. Numerous ecological drivers and species-specific factors are suggested to set the conditions for an evolutionary shift from arboreality to terrestriality, and current environmental conditions may provide analogous scenarios to those transitional periods. Therefore, we investigated predominantly arboreal, diurnal primate genera from the Americas and Madagascar that lack fully terrestrial taxa, to determine whether ecological drivers (habitat canopy cover, predation risk, maximum temperature, precipitation, primate species richness, human population density, and distance to roads) or species-specific traits (body mass, group size, and degree of frugivory) associate with increased terrestriality. We collated 150,961 observation hours across 2,227 months from 47 species at 20 sites in Madagascar and 48 sites in the Americas. Multiple factors were associated with ground use in these otherwise arboreal species, including increased temperature, a decrease in canopy cover, a dietary shift away from frugivory, and larger group size. These factors mostly explain intraspecific differences in terrestriality. As humanity modifies habitats and causes climate change, our results suggest that species already inhabiting hot, sparsely canopied sites, and exhibiting more generalized diets, are more likely to shift toward greater ground use.

Tropical forests support a diversity of plants. Many of them are threatened, emphasising that their shared use by people and wildlife may benefit their conservation. Litt forests of southeast Madagascar, home to seven threatened lemur species, provide the Antanosy people with natural resources. In the early 2000s, protected areas were established in two regions that historically incurred different levels of anthropogenic pressures: Sainte Luce and Mandena. We explored the local use of plants as medicine, construction materials and firewood, and examined the overlap of plants used by people and the red-collared brown lemur (Eulemur collaris), the largest lemur in this ecosystem and an important seed disperser. Between July and October 2018, 60 adults (30 women, 30 men) participated in semi-structured interviews. Our findings show 122 plants are locally used as medicines, 60 as construction materials, and 71 as firewood. Of all utilitarian plants, 52 were confirmed in this lemur’s diet. Sainte Luce participants reported they used a higher diversity of species in all three categories. Western medicines were available and preferred to medicinal plants, but the choice also often depended on the health condition being addressed. Firewood was preferred to charcoal for cooking. Resource restrictions of the protected areas has negatively affected the local people. Local ethnobotanical knowledge reflects the importance of plants, while differences in plant use of the two communities reflect differences in biodiversity and socio-economic circumstances. Emphasising this interdependence, especially in forest restoration, could be a path towards conservation of plants, lemurs, and people, as well as traditional livelihoods.

This study provides new findings on the flexible activity of Prolemur simus in an anthropogenically modified habitat in the rural commune of Tsaratanana, eastern Madagascar. Based on camera-trap data, we compared the temporal distribution of activity of one group of lemurs between the forest edge and the forest core. We also investigated the possible influence of nocturnal luminosity on the activity cycle. The analysis was conducted using Kernel Density estimates and the R package OVERLAP. The distribution across the 24-h cycle confirmed that Prolemur simus is cathemeral in the wild. The lemurs displayed three peaks of activity: one during the night and two coinciding with morning and evening twilights. The highest proportions of nocturnal activity occurred at the forest edge and at low moon luminosity suggesting a possible anti-predator and/or human-avoidance strategy. The flexible activity of Prolemur simus may contribute to the tolerance of this Critically Endangered species to anthropogenic disturbance.

The ecological-constraints model posits that living in larger groups is associated to higher travel costs and reduced nutritional intake due to within-group feeding competition setting upper group size limits. While this is critical for frugivorous mammals, the model is less ubiquitous for folivores who feed on more abundant and evenly distributed food. The seasonally frugivorous diet of western gorillas (Gorilla gorilla) provides the opportunity to study the ecological-constraints model in the largest primate species. We investigated how two groups of western gorillas of differing sizes (N = 9, N = 15) in Central African Republic, responded to seasonal variation in fruit availability in terms of activity and diet. We used continuous focal animal sampling during periods of high (July–August 2011) and low (October 2011–January 2012) fruit availability, measured by monthly phenological scores. While diet diversity, resting and moving time did not differ between groups, overall the smaller group spent more time feeding than the larger group although this became less evident when fruit was more available. The smaller group was more frugivorous than the larger group. However, the larger group increased more steeply fruit consumption when fruit was more available, and incorporated more insects, young leaves and bark when fruit was less available, when compared to the smaller group. Up to a certain limit, the flexibility of large, seasonal frugivores to survive on a more folivorous diet may buffer the upper limit group size, suggesting deviation from the ecological-constraints model as in some folivores.

Seasonal environments challenge animals, increasing the complexity of locating resources. Navigation may rely on ‘habitual routes’ or ‘Euclidean’ maps: following established routes or computing novel paths, respectively. Folivores are presumed to rely on evenly distributed resources and thus have a reduced reliance on navigation. We tested whether the navigation strategy of southern bamboo lemurs, Hapalemur meridionalis, a primarily folivorous strepsirrhine that periodically consumes fruit, varies across seasons. We recorded behaviour and location of three social groups during full-day, focal follows during January–December 2013. We analysed the macronutrient components of food items. Bamboo lemurs travelled through habitual routes during periods of food scarcity but relied on nodes (i.e. intersections where directional decisions are made) to navigate throughout the year. Likely, habitual route navigation promoted an energy-saving strategy during lean periods by easing lemur locomotion across the forest. In contrast, lemurs relied on Euclidean navigation during food abundant periods. The continuous use of nodes suggest that nodes may act as cognitive anchors to support efficient directional decisions across seasons. Linearity increased during periods of resource abundance when feeding on energy-rich items and during periods of scarcity to reach latrines. By travelling increasingly linearly towards energy-rich items, lemurs maximized energy intake during periods of food abundance. Overall, bamboo lemurs’ combination of both Euclidean and route-based navigational strategies demonstrates a cognitive adaptation for coping with seasonal resource variability in a way that challenges previous research postulating constrained spatial skills in folivorous strepsirrhines.

The relative importance of climate shifts and human activities on Madagascar's Holocene ecological transitions is highly contentious. Increasing evidence supports a scenario of negligible impact of climate changes on megafauna extinctions. However, a comprehensive picture can only be obtained by overcoming a dichotomic view and weighing the contributions of diverse disciplines in an integrated framework. Multidisciplinary approaches implementing genetic data reveal scenarios of higher complexity during the human colonization of the island, sometimes unevenly related to climate-driven landscape transformations. Reconstructions of Holocene demographics from the genomes of living and sub-fossil species show signs of a closer association between past population size contractions and paleo-climatic shifts. From this perspective, the main causes of the megafaunal demise likely trace back to the mutual reinforcement between the ecological shifts that followed the settlement of new immigrants and those induced by millennial climate trends.

Habitat loss and fragmentation pose a significant threat to many primate species worldwide, yet community level responses are complex and nuanced. Despite repeated calls from primatologists and the wider conservation community to increase monitoring initiatives that assess long-term population dynamics, such studies remain rare. Here we summarise results from a longitudinal study set in the littoral forests of southeast Madagascar. Littoral forests are a useful model for monitoring lemur population dynamics, as they are relatively well-studied and their highly fragmented nature enables the effect of forest size and anthropogenic impacts to be examined. This study focuses on three Endangered nocturnal lemur species – Avahi meridionalis, Cheirogaleus thomasi and Microcebus tanosi – across three forest fragments of different size and with different usage histories. Between 2011 and 2018, we walked 285km of line transect and recorded 1,968 lemur observations. Based on Distance Sampling analysis our results indicate that nocturnal lemurs respond to forest patch size and to levels of forest degradation in species-specific ways. The largest species, A. meridionalis, declined in density and encounter rate over time across the three study forests. C. thomasi populations appeared stable in all three fragments, with densities increasing in the most degraded forest. M. tanosi encounter rates were extremely low across all study fragments but were lowest in the most heavily degraded forest fragment. Our results emphasise the importance of localised pressures and species-specific responses on population dynamics. Monitoring population trends can provide an early warning signal of species loss and species-specific responses can inform crucial intervention strategies.

Establishing reintroduced primates in a suitable predetermined area has proven to be a challenge. Establishment is the first major step that has to be taken in the long process of reintroduction. When this first goal is not achieved, the chances of success decline drastically. Understanding the main determinants of establishment is therefore crucial for reintroduction success. This study examined the influence of three independent factors on the establishment success of reintroduced spider monkeys. We analysed data from the releases of eight groups of black-faced spider monkeys (Ateles chamek), which are part of the official reintroduction program of spider monkeys in the South Eastern Peruvian Amazon. Establishment success was measured by the proportions of individuals within groups  that were found in the target area six months after release. The hours research assistants and volunteers spent with the group within the first three months after release – in the context of post-release monitoring – was shown to have a positive effect on the establishment success of the released group in the target area. The presence of an already established group in the area was found to have also a significant positive effect on establishment success. The influence of the days of post-release food provisioning had no effect  Our findings emphasize the importance of long-term monitoring programs to help increase the efficiency of primate reintroductions.

Traditional socio-ecological models consider that folivorous primates experience limited feeding competition due to the low quality, high abundance, and even distribution of leaves. Evidence from several folivorous species that experience similar constraints to frugivores does not support this hypothesis. The sympatric lemur genera Avahi (Indriidae) and Lepilemur (Lepilemuridae) are good models to understand how food availability constrains folivores since they are both nocturnal, folivorous, and have a comparable body mass. Here we investigate how two nocturnal folivorous primates, Avahi meridionalis and Lepilemur fleuretae, living in the lowland rain forest of Tsitongambarika, South-East Madagascar, partition their dietary niche and are influenced by seasonality of young leaves. To account for food availability, we collected annual phenological data on 769 trees from 200 species. We also collected behavioural data on 5 individuals per lemur species from August 2015 to July 2016 via continuous focal sampling. We found the phenological profile to be seasonal with peaks of leaf flushing, flowering, and fruiting occurring in the austral summer. The two species showed limited dietary overlap (37% rich period, 6% lean period), and A. meridionalis showed higher feeding time and longer daily distances travelled during the rich  period. L. fleuretae showed a dietary shift during the lean period, relying more on mature leaves (73.3% during the lean period, 13.5% during the rich period) but maintaining similar activity levels between seasons. The time spent feeding on food items by A. meridionalis was positively correlated with the nitrogen content and negatively correlated with polyphenols in food items during the rich period. We highlighted a clear effect of the seasonality of young leaves on the diet, nutritional content, activity patterns, and daily distances travelled by two folivorous species, which can be linked to nutrient balancing and time-minimising versus energy-maximising strategies.

Whilst the drivers of primate persistence in forest fragments have been often considered at the population level, the strategies to persist in these habitats have been little investigated at the individual or group level. Considering the rapid variation of fragment characteristics over time, longitudinal data on primates living in fragmented habitats are necessary to understand the key elements for their persistence. Since translocated animals have to cope with unfamiliar areas and face unknown fluctuations in food abundance, they offer the opportunity to study the factors contributing to successful migration between fragments. Here, we illustrated the evolution of the foraging strategies of translocated collared brown lemurs (Eulemur collaris) over an 18-year period in the Mandena Conservation Zone, south-east Madagascar. Our aim was to explore the ability of these frugivorous lemurs to adjust to recently colonized fragmented forests. Although the lemurs remained mainly frugivorous throughout the study period, over the years we identified a reduction in the consumption of leaves and exotic/pioneer plant species. These adjustments were expected in frugivorous primates living in a degraded area, but we hypothesize that they may also reflect the initial need to cope with an unfamiliar environment after the translocation. Since fragmentation is often associated with the loss of large trees and native vegetation, we suggest that the availability of exotic and/or pioneer plant species can provide an easy-to-access, non-seasonal food resource and be a key factor for persistence during the initial stage of the recolonization.

Primates worldwide are faced with increasing threats making them more vulnerable to extinction. Anthropogenic disturbances, such as habitat degradation and fragmentation, are among the main concerns, and in Madagascar, these issues have become widespread. As this situation continues to worsen, we sought to understand how fragmentation affects primate distribution throughout the island. Further, because species may exhibit different sensitivity to fragmentation, we also aimed to estimate the role of functional traits in mitigating their response. We collated data from 32 large‐bodied lemur species ranges, consisting of species from the families Lemuridae (five genera) and Indriidae (two genera). We fitted Generalized Linear Models to determine the role of habitat fragmentation characteristics, for example, forest cover, patch size, edge density, and landscape configuration, as well as the protected area (PA) network, on the species relative probability of presence. We then assessed how the influence of functional traits (dietary guild, home range size) mitigate the response of species to these habitat metrics. Habitat area had a strong positive effect for many species, and there were significantly negative effects of fragmentation on the distribution of many lemur species. In addition, there was a positive influence of PAs on many lemur species’ distribution. Functional trait classifications showed that lemurs of all dietary guilds are negatively affected by fragmentation; however, folivore‐frugivores show greater flexibility/variability in terms of habitat area and landscape complexity compared to nearly exclusive folivores and frugivores. Furthermore, species of all home range sizes showed a negative response to fragmentation, while habitat area had an increasingly positive effect as home range increased in size. Overall, the general trends for the majority of lemur species are dire and point to the need for immediate actions on a multitude of fronts, most importantly landscape‐level reforestation efforts.

1. Elevation gradients correlate with changes in several environmental conditions and are known to be related to animal abundance. Animals in regions with a naturally limited extent of lowland rainforest are expected to have evolved adaptations to intermediate elevations that provided a stable environment during their evolution.
2. Since the lowland rainforest of Madagascar has a limited extent and suffers from increasing anthropogenic pressure, it is essential to understand how well species tolerate intermediate and high elevations. In this study, we aim to quantify the relationship between lemur abundance and elevation in the eastern rainforest of Madagascar.
3. We correlated abundance data on 26 lemur species (10 genera), including 492 records from 26 studies, with elevation. We analysed the consistency of correlations across species with a meta‐analytical approach. We controlled for species’ body mass, elevational range and median elevation. We then ran generalised linear mixed models to determine whether lemur abundance was related to elevation, body mass, plant productivity and anthropogenic disturbance.
4. Overall, the abundance of lemur species in Malagasy rainforests was negatively correlated with elevation, and species occupying broader elevational ranges showed stronger correlations. Body mass was not related to species’ tolerance of high elevations. Even though several lemur species are able to occupy the entire elevation gradient, the few remaining patches of lowland rainforests host lemur species at greater abundances than other sites. Abundance across species was negatively related to body mass, elevation and seasonality in plant productivity and positively related to plant productivity.
5. Despite the ecological flexibility of many lemur species, the remnant patches of lowland rainforests host the highest levels of lemur abundance and are key to lemur conservation. It is crucial to preserve this priority habitat both for biodiversity conservation and for our understanding of lemur adaptations.

Time is considered a resource in limited supply, and temporal niche separation is one of the most common strategies that allow ecologically similar species to live in sympatry. Mechanisms of temporal niche separation are understudied especially in cryptic animals due to logistical problems in gathering adequate data. Using high-frequency accelerometers attached to radio-collars, we investigated whether the ecologically similar lemurs Avahi meridionalis and Lepilemur fleuretae in the lowland rainforest of Tsitongambarika, south-eastern Madagascar, show temporal niche separation. Accelerometers stored data with a frequency of 1 Hz for a total of 71 days on three individuals of A. meridionalis and three individuals of L. fleuretae. We extrapolated motor activity patterns via the unsupervised learning algorithm expectation maximisation and validated the results with systematic behavioural observations. Avahi meridionalis showed peaks of activity at twilights with low but consistent activity during the day, while L. fleuretae exhibited more activity in the central hours of the night. Both lemur species had their activity pattern entrained by photoperiodic variations. The pair-living A. meridionalis was found to be lunarphilic while the solitary-living L. fleuretae was lunarphobic. We suggest that these activity differences were advantageous to minimise feeding competition, as an anti-predator strategy, and/or for dietary-related benefits. These findings demonstrate a fine-tuned temporal partitioning in sympatric, ecologically similar lemur species and support the idea that an activity spread over the 24-h, defined here as cathemerality sensu lato, is more common than previously thought in lemurs.

Significance statement

Ecologically similar species may exhibit temporal niche partitioning and separate their peaks of activity when co-occurring in an area. We show for the first time that the mainly nocturnal genus Avahi can exhibit high crepuscular activity with low but consistent bouts of activity (up to 44.6% of daily activity) during the day. We defined this activity as cathemerality sensu lato as opposed to the cathemerality sensu stricto observed in Eulemur sp. We suggest that this flexible activity may be advantageous for the species to minimise feeding competition and predatory pressure, and/or to provide dietary-related benefits. This finding in the secondary nocturnal genus Avahi supports the idea that activity patterns in lemurs are graded and traditional categorisations are inadequate.

Results. The overall genetic diversity of E. collaris in the southeastern coastal region of Madagascar was lower than in other populations, as well as in other lemur species. The population appears highly structured, with less variable and more inbred groups inhabiting the littoral forest fragments compared to the inland area. Major barriers to gene flow were identified isolating littoral forest fragments from each other and from the inland lowland humid forest.

Discussion. Medium to long-term drift and scarce gene flow is the scenario that best explains the current genetic distribution. Habitat discontinuities such as rivers and grassland between forest fragments played a major role in structuring the population. A common history of size contraction is pointed out by several genetic estimators, indicating a possible ecological crisis triggered around 1,300 years ago. The adoption of strategies aimed at facilitating gene flow and population growth appears crucial to delay further loss of genetic diversity.

The proximate and ultimate determinants that may have prompted some primates to shift from an arboreal to terrestrial feeding niche, whether due to environmental change, seasonality, and/or predation pressure, are poorly understood. Within a fragmented littoral forest in southeast Madagascar, an arboreal strepsirrhine population spends a large proportion of time on the ground, thus we aimed to identify which factors influence terrestrial feeding.

Methods

From January to December 2013, we conducted 103 full-day focal follows on three social groups of southern bamboo lemurs H. meridionalis. We continuously recorded feeding time on all arboreal and terrestrial items, as well as whether the focal individual was under the canopy or exposed, and the distance to their nearest conspecific neighbor. All observed food items were collected and analyzed for macronutrient content. Daily climatic variables (temperature, precipitation), resource seasonality, daily path length (DPL), along with dietary and predation risk proxies, were used as fixed effects in a linear mixed model, with the daily proportion of terrestrial feeding as the dependent variable.

Results

Our model indicated that daily terrestrial feeding increased at cooler temperature, was associated with reduced DPL, and the intake of dietary metabolizable energy increased as terrestrial feeding increased. All other fixed effects were not significant predictors.

Discussion

Our study provides a window into the ultimate determinants of niche expansion: ancestral primates, in absence of their primary resources, may have initially descended to the ground in peripheral population range areas where the benefits (e g., nutritional pay-off) out-weighed the costs.

in size, and the vast diversity of plants and animals living in it is now highly threatened. In the

south-east of the island, a few fragments of littoral forest still harbour small populations of the

endangered collared brown lemur, Eulemur collaris . In 2000, the rapid devastation of one of these forest fragments by charcoal makers (in the area of Mandena) elicited a rescue action and relocation of 28 E. collaris into a nearby, but recently protected, fragment. Since then, some of the relocated animals have been observed by a team of observers from QMM (QIT Madagascar Minerals) in order to get insight into their adaptation to the new area. Since there is a paucity of longterm data on prosimians relocations, these monitoring efforts are crucial to understand how

prosimians in general and lemurs in particular may adapt to unfamiliar areas. We analysed dietary choice in one relocated group of E. collaris throughout several years and we compared it

with data from other populations to assess whether the release site provided a suitable habitat.

We analysed data collected by local QMM assistants in 2007, 2008, 2009 and 2013. The analysis indicated that the diet of E. collaris remained mainly frugivorous over the years, which is the usual dietary regime shown by this species in natural situations. A Mixed Model indicated that seasonal fluctuations were wider than inter-annual differences, which is in line with the highly variable tree phonological pattern in this habitat. This multi-annual study indicated that E. collaris did not modify its overall diet at the release site in terms of major food categories but the use of tree species varied significantly throughout the years. Summarizing, our work suggests that Eulemur species may tolerate relocations and the disruptive effects of these operations are not apparent on the animals’ behavioural ecology over the long-term.  (Abstract presented on the 6th European Federation for Primatology Meeting, Rome, Italy, August 25-28, 2015)

compared to those in the wild. Obesity causes health issues including reproductive problems,

cardiovascular disease and diabetes – it is therefore vital to know influencing factors and preventative measures. Captive individuals are classified as overweight or obese compared to wild weight averages. Food intake and activity pattern observations were conducted to determine differences in amounts consumed, items consumed and time active between individuals. A questionnaire was distributed to UK institutions, exploring factors potentially influencing body weight, such as age, gender, enclosure type, group size, night access and browse presence, and to determine captive weight ranges. No relationship was found between body weight and total grams consumed, and no individual consumed near the average provisioned. There was a strong tendency towards a positive trend between body weight and metabolisable energy. All individuals spent more time inactive than active, with little variation between them. No correlation was found between body weight and age, group size, dominance, or presence of browse. Captive weight ranges were higher than wild ranges, standard enclosures had significantly heavier occupants, and individuals with full night access were significantly heavier than those with weather dependent access. Males were significantly heavier than females, which is unexpected given female dominance. The average weight for captive Lemur catta was 2,603 g compared to 2,219 g for wild individuals, which provides a more realistic target weight and reclassifies the number of individuals regarded as overweight or obese, with long-term husbandry implications. Metabolisable energy intake was the most influential factor on body weight, but no one aspect explained the variation between individuals. Additional factors must play a role. This study emphasises the importance of conducting food intake and activity pattern observations before making any weight-induced husbandry changes. This research project complied with the European Directive 2010/63/EU and the International Primatological Society (IPS) Guidelines for the Use of Nonhuman Primates in Research. (Abstract presented on the 6th European Federation for Primatology Meeting. Rome, Italy, August 25-28, 2015)

Neotropical primates and both taxa are well known for their ability to survive in highly disturbed

habitats. However, there is a lack of information on the Ecuadorian populations of these two genera which occur there in some of the most threatened South American ecosystems, including the coastal region located in the Tumbes-Chocó-Magdalena hotspot. This study aimed to evaluate the effects of anthropogenic disturbance and habitat characteristics on the population density of the Vulnerable mantled howler monkey (Alouatta palliata aequatorialis) and the Critically Endangered white-fronted capuchin monkey (Cebus albifrons aequatorialis) in the Marine and Coastal Wildlife Refuge of Pacoche in western Ecuador. Although protected, illegal activities inside the area include slash-and-burn agriculture, natural resource extraction and small-scale hunting. We distributed eighteen transects of 1 km each in the protected area in order to determine population density in the reserve and assess the impact of anthropogenic disturbance. Each transect was walked 5 times, totalling over 90 km of surveying effort, yet we did not detect capuchins in the area while walking the transects. White-fronted capuchin monkeys were observed on three occasions, confirming their presence in the area. We estimated mantled howler monkey density to be 20.44 ind/km 2, and the average group size was 9.28 ± SD 4.30 individuals. Results suggest that probability of detection varied with group size and A. palliata aequatorialis density followed a half normal distribution correlated with distance to the road. Canopy cover was also associated with probability of detection, which highlights the importance of habitat connectivity. The very low detection of white-fronted capuchins in the area indicates the need for immediate conservation actions for the primates of the Ecuadorian coastal region. (Abstract presented in the 6th European Federation for Primatology Meeting, Rome Italy, August 25-28, 2015)

of its endemic species. In the south-east of the island, this habitat has been exposed to heavy fragmentation due to shifting cultivation and logging. This area faces an additional risk due to the mining of titanium deposits. Considering these threats, it is crucial to understand the key drivers of forest restoration and habitat corridors. As the largest seed disperser in this ecosystem, the collared brown lemur (Eulemur collaris) is known to disperse seeds of up to 36.5 mm in length. We thus hypothesize that the disappearance of this lemur may cause cascade effects for large-seeded plant regeneration. We investigated this hypothesis using three forest fragments of a similar size: one with high densities of E. collaris , one with low densities of E. collaris , and one in which the species disappeared long ago. Regenerating saplings, ranked by classes of height, were sampled in a total of 300 small plots of 2 × 2 m each. At each point, mature trees were also recorded via the point-quarter method to control for the presence of parent trees. Differences between fragments in the frequencies of the overall regeneration, lemur dispersed species, and Eulemur dispersed species were explored through a Generalized Linear Model with negative binomial distribution. Lemur and Eulemur dispersed plant species were identified on the basis of observational data and seed size. The results showed that both overall regeneration and the regeneration of the lemur dispersed species did not differ between fragments. In contrast, the two fragments in which E. collaris persists showed higher regeneration of tree species exclusively dispersed by this lemur, as compared to the fragment in which the species has been eradicated. This work demonstrates the key role of medium/large frugivorous lemurs for the maintenance of forest diversity in Madagascar (Abstract presented at the 6th European Federation for Primatology Meeting, Rome, Italy, August 25-28, 2015)

biodiversity is severely threatened by habitat disturbance due to tavy (slash and burn agriculture), land conversion for rice cultivation, illegal hardwood logging and bushmeat hunting. Understanding species specific responses to this habitat disturbance is crucial when designing conservation plans. We surveyed three nocturnal lemur species in four forest types of varying habitat disturbance on the Masoala Peninsula, northeastern Madagascar. We present here the first abundance and density estimates for the Endangered Avahi mooreorum and Lepilemur scottorum, and a currently undescribed Microcebus sp. Distance sampling surveys were conducted on 11 transects, covering a total of 33 km. Overall density estimates for the study area are provided for Microcebus sp. and Avahi mooreorum using Distance 6.0. We collected data on tree height, bole height, DBH, canopy cover and tree density using point quarter sampling to characterise the four forest types (primary lowland, primary littoral, selectively logged and agricultural mosaic). Species encounter rates ranged from 1.44–2.78 ind/km ( Microcebus sp.), 0.22–2.89 ind/km (Avahi mooreorum) and 0–1.22 ind/km (Lepilemur scottorum) . Species density estimates were calculated at 232.31 ind/km 2  ( Microcebus sp.) and 121.21 ind/km 2  (Avahi mooreorum) , while no density estimate is provided for Lepilemur scottorum due to a small sample size. Microcebus sp. showed no significant effect of forest type on abundance, and its small body size, omnivorous diet and generalised locomotion appears to allow it to tolerate a variety of habitat disturbance. Both Avahi mooreorum and Lepilemur scottorum showed significant effects of forest type on their abundance. This study would suggest that the specialist locomotion and diet of Avahi mooreorum and Lepilemur scottorum make them more susceptible to the effects of habitat disturbance than Microcebus sp. (Abstract presented at the 6th European Federation for Primatology Meeting, Rome, Italy, August 25-28, 2015)

The ability to operate during the day and at night (i.e., cathemerality) is common among mammals but has rarely been identified in primates. Adaptive hypotheses assume that cathemerality represents a stable adaptation in primates, while nonadaptive hypotheses propose that it is the result of an evolutionary disequilibrium arising from human impacts on natural habitats. Madagascar offers a unique opportunity to study the evolution of activity patterns as there we find a monophyletic primate radiation that shows nocturnal, diurnal, and cathemeral patterns. However, when and why cathemeral activity evolved in lemurs is the subject of intense debate. Thus far, this activity pattern has been regularly observed in only three lemurid genera but the actual number of lemur species exhibiting this activity is as yet unknown. Here we show that the ring-tailed lemur, Lemur catta, a species previously considered to be diurnal, can in fact be cathemeral in the wild. In neighboring but distinct forest areas these lemurs exhibited either mainly diurnal or cathemeral activity. We found that, as in other cathemeral lemurs, activity was entrained by photoperiod and masked by nocturnal luminosity. Our results confirm the relationship between transitional eye anatomy and physiology and 24-h activity, thus supporting the adaptive scenario. Also, on the basis of the most recent strepsirrhine phylogenetic reconstruction, using parsimony criterion, our findings suggest pushing back the emergence of cathemerality to stem lemurids. Flexible activity over 24-h could thus have been one of the key adaptations of the early lemurid radiation possibly driven by Madagascar's island ecology.

 Facets of habitat quality which allow species persistence in forest fragments are an important aspect for primate conservation. Mantled howler monkeys (A. palliata) seem to be tolerant of habitat fragmentation, though the limits of this flexibility are not yet clear. In some areas, howler monkey densities in small, primary forest fragments are among the highest ever recorded for the species. We hypothesize that if high density is also determined by habitat carrying capacity; primaryvegetation should provide higher quality resources. Alternatively, if density is just the consequence of crowding, this would decrease the quality of the diet compared to that of monkeys living in non-crowded forests. To test these hypotheses, we studiedfour howler monkey groups at La Suerte Biological Field Station, North-eastern Costa Rica. Two groups occurred in a small primary forest with high howler density, while two groups lived in a large secondary forest with lower density. We collected behavioural data via a 5-min Focal Animal Sampling to estimate activity, habitat use and diet. Food samples were also collected and then analyzed to evaluate their nutritional contents. Moreover, we registered GPS coordinates and estimated home-ranges and mean inter-location distances. Our results show that primary forest food samples contained a significantly lower amount of fiber and a higher protein/fiber ratio than samples from the secondary habitat. Also, primary forest groups used larger feeding trees and moved substantially less than secondary forest groups. Our results support the hypothesis that the primary forest provides higher quality resources than the secondary habitat and, as a possible consequence, howler monkeys living in the latter have to move more to meet their energy requirements. 

Primates deal with fluctuations of the thermal environment by both physiological and behavioral mechanisms of thermoregulation. In this article we focus on nonhibernating lemurs, which are hypometabolic and have to cope with a seasonal environment. Behavioral thermoregulation has received little attention compared with specific physiological adaptations to seasonality, i.e., hibernation and torpor, which characterize a number of lemurs. We investigated the role of seasonality and dietary-related factors in determining frequencies of resting, social and postural thermoregulation, and microhabitat selection in collared lemurs, Eulemur collaris. We observed two groups of collared lemurs over a 14-month period in the littoral forest of Sainte Luce, Southern Madagascar. Frequencies of total resting and time spent in huddling, prone, and curled postures were collected via 5-min instantaneous sampling. Microhabitat selection was evaluated as the proportion of time spent in the upper canopy as compared with other layers. Climatic variables were recorded by automatic data loggers, while dietary variables were derived from phenological data and nutritional analyses of the ingested food items. We weighted the combined effects of climatic and dietary variables on the different types of behavioral thermoregulation by means of canonical correlation analysis. The model with the strongest canonical correlation included a first root representing mainly feeding time, day length, and ambient temperature and a second root representing diet quality and height of feeding trees. The output indicated that collared lemurs adapt to thermal and dietary-related metabolic stress by adjusting resting time, social, and postural thermoregulation.

Background
Frugivorous primates are known to encounter many problems to cope with habitat degradation, due to the fluctuating spatial and temporal distribution of their food resources. Since lemur communities evolved strategies to deal with periods of food scarcity, these primates are expected to be naturally adapted to fluctuating ecological conditions and to tolerate a certain degree of habitat changes. However, behavioral and ecological strategies adopted by frugivorous lemurs to survive in secondary habitats have been little investigated. Here, we compared the behavioral ecology of collared lemurs (Eulemur collaris) in a degraded fragment of littoral forest of south-east Madagascar, Mandena, with that of their conspecifics in a more intact habitat, Sainte Luce.
Methodology/Principal Findings Lemur groups in Mandena and in Sainte Luce were censused in 2004/2007 and in 2000, respectively. Data were collected via instantaneous sampling on five lemur groups totaling 1,698 observation hours. The Shannon index was used to determine dietary diversity and nutritional analyses were conducted to assess food quality. All feeding trees were identified and measured, and ranging areas determined via the minimum convex polygon. In the degraded area lemurs were able to modify several aspects of their feeding strategies by decreasing group size and by increasing feeding time, ranging areas, and number of feeding trees. The above strategies were apparently able to counteract a clear reduction in both food quality and size of feeding trees. Conclusions/Significance Our findings indicate that collared lemurs in littoral forest fragments modified their behavior to cope with the pressures of fluctuating resource availability. The observed flexibility is likely to be an adaptation to Malagasy rainforests, which are known to undergo periods of fruit scarcity and low productivity. These results should be carefully considered when relocating lemurs or when selecting suitable areas for their conservation.

Malagasy primates of the genus Hapalemur are exceptional in their exhibition of specialisations allowing for a folivorous diet despite their small body size. Members of this group are well known for their preference for specific parts of woody bamboo, the primary food resource throughout much of their range. The southern gentle lemur (H. meridionalis), however, inhabits littoral forests that contain little or no woody bamboo. Similar to its closely related congener, the Alaotran gentle lemur (H. alaotrensis), the question is raised as to how these lemurs subsist in this ecological context. The aim of this study was to gain an initial understanding of the ecological niche of the southern gentle lemur in the threatened ecosystem of the littoral forest of southeastern Madagascar. Lemurs were habituated and observed over a 3-month period during the austral winter, allowing for collection of both continuous and instantaneous focal data on their feeding ecology. Preferred food species were identified and collected, and biochemical analyses determined macronutrient and secondary compound values for consumed food items. The diet of the southern gentle lemur was found to be of low nutritional quality, as evaluated through the low protein-to-fibre ratio, especially when compared with other folivores. This lemur is also unique in spending a majority of its time grazing on terrestrial grasses (family Poaceae) during the resource-poor winter months. Our data indicate that Hapalemur spp. possess a behavioural flexibility, and possibly, digestive abilities, higher than previously thought for an animal of its small body size.

Trade in primates is seen as a significant impediment to their conservation. Primates are traded both domestically and internationally, in order to supply, amongst others, biomedical industries and pharmaceutical markets, the entertainment business, or pet markets. Primate meat is consumed globally, whereas body parts are used as ingredients in traditional medicine or sold as curios. All international trade in primates is regulated through the Convention on International Trade in Endangered Species of Wild Flora and Fauna (CITES), to which all but 2 primate range countries are signatory. The last 15 years has seen a linear increase in the export of live primates (each year 3500 more individuals are exported), with China being, numerically, the largest exporter. While the trade in live primates worldwide involves tens, if not hundreds, of thousands of individuals a year, the trade in dead primates involves millions of animals a year. We introduce here a series of studies dealing with various aspects of the primate trade. We hope that these studies will urge others to quantify the extent of trade in primates alive and dead in both domestic and international contexts, allowing us to find ways to mitigate the consequences of this trade to the conservation of primates.