Search

Hunting is one of the greatest threats to nonhuman primates worldwide. Despite Madagascar’s status as a primate mega-diversity country, a critical lack of information on the hunting of lemurs at the national scale persists. Here, we synthesize the current state of knowledge of the annual rates of household-level lemur hunting near ten protected areas, representing most ecoregions in Madagascar. We examine geographic and taxonomic variation in lemur hunting, including an analysis of hunting relative to species density, extinction risk, and intrinsic ecological characteristics of species. We found that lemurs are commonly hunted across Madagascar; the rural households in our study ate, on average, more than one lemur each year, or a median of 4.1% of the lemur species’ population size where densities are known. However, this pressure varied significantly across sites and species, reaching its highest levels in the northeastern rainforest region. While hunting levels are concerning for numerous threatened species, hunting pressure was driven primarily by species availability, and among ecological traits, small body size was related to increased hunting; however, conservation status showed no such relationship. This first national-level assessment of hunting, including one-third of Madagascar’s lemur species and more than a tenth of the world’s primates, identifies regional variation and lemur taxa at acute risk from hunting—important steps toward developing targeted strategies to conserve one of the world’s most threatened groups of vertebrates.

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 (bodymass, 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.

Interspecific competition can strongly influence patterns of space use in animal communities, particularly between closely related species, and may be exacerbated in marginal habitat. This may be important in Madagascar, as lemurs face diminishing resources due to deforestation. We examined the range overlap and spatiotemporal relationships of three species of frugivorous lemur in the fragmented forests of Kianjavato, Madagascar. We conducted simultaneous location and behaviour sampling of black-and-white ruffed lemurs, Varecia variegata, red-fronted lemurs, Eulemur rufifrons, and red-bellied lemurs, Eulemur rubriventer, at two sites over a period of 11 months. We used Doncaster's index of dynamic interaction to investigate the relative amount of time species spent within 30 m and 100 m of each other, compared to the time expected based on random use of location points. All three species showed low core range overlap compared to home range overlap, and while core overlap was higher between interspecific groups than intraspecific groups, the difference was not substantial. Conversely, no spatiotemporal avoidance was observed, and red-fronted lemurs showed positive association (indicating possible attraction) with both red-bellied and ruffed lemurs. These positive spatiotemporal associations may be related to shared resource use in small forests, or predation avoidance strategies. At present, these species may rely more on spatial segregation and niche separation than spatiotemporal avoidance to minimize interspecific competition.

Primate species face growing risks of extinction throughout the world. To better protect their populations, effective monitoring techniques are needed. The goal of this study was to evaluate the use of arboreal camera traps and occupancy modeling as conservation tools for threatened lemur species. This project aimed to (1) estimate the occupancy and detection probabilities of lemur species, (2) investigate factors potentially affecting lemur habitat use, and (3) determine whether ground or arboreal cameras are better for surveying lemur assemblages. We conducted camera trapping research in five forest fragments (total trap nights = 1770; 900 arboreal trap nights (134 photo events); 870 ground trap nights (2 photo events)) and reforestation areas (total trap nights = 608; 1 photo event) in Kianjavato, Madagascar from May to September 2019. We used arboreal trap data from fragments to estimate occupancy for five species: the red-fronted brown lemur (Eulemur rufifrons; ψ = 0.54 ± SD 0.03), Jolly's mouse lemur (Microcebus jollyae; ψ = 0.14 ± 0.17), the greater dwarf lemur (Cheirogaleus major; ψ = 0.42 ± 0.30), the red-bellied lemur (Eulemur rubriventer; ψ = 0.24 ± 0.03), and the black-and-white ruffed lemur (Varecia variegata; ψ = 0.24 ± 0.08). Tree diameter, elevation, distance to village, and canopy connectivity were important predictors of occupancy, while camera height, canopy connectivity, fragment ID, and fragment size predicted detection. Arboreal cameras recorded significantly higher species richness compared with ground cameras. We suggest expanded application of arboreal camera traps in future research, but we recommend longer trapping periods to better sample rarer species. Overall, arboreal camera trapping combined with occupancy modeling can be a highly efficient and useful approach for monitoring and predicting the occurrence of elusive lemur species and has the potential to be effective for other arboreal primates and canopy taxa across the globe.

A variety of factors can affect the biodiversity of tropical mammal communities, but their relative importance and directionality remain uncertain. Previous global investigations of mammal functional diversity have relied on range maps instead of observational data to determine community composition. We test the effects of species pools, habitat heterogeneity, primary productivity and human disturbance on the functional diversity (dispersion and richness) of mammal communities using the largest standardized tropical forest camera trap monitoring system, the Tropical Ecology Assessment and Monitoring (TEAM) Network. We use occupancy values derived from the camera trap data to calculate occupancy-weighted functional diversity and use Bayesian generalized linear regression to determine the effects of multiple predictors. Mammal community functional dispersion increased with primary productivity, while functional richness decreased with human-induced local extinctions and was significantly lower in Madagascar than other tropical regions. The significant positive relationship between functional dispersion and productivity was evident only when functional dispersion was weighted by species' occupancies. Thus, observational data from standardized monitoring can reveal the drivers of mammal communities in ways that are not readily apparent from range map-based studies. The positive association between occupancy-weighted functional dispersion of tropical forest mammal communities and primary productivity suggests that unique functional traits may be more beneficial in more productive ecosystems and may allow species to persist at higher abundances.

Background Habitat disturbance affects the biology and health of animals globally. Understanding the factors that contribute to the differential responses of animals to habitat disturbance is critical for conservation. The gut microbiota represents a potential pathway through which host responses to habitat disturbance might be mediated. However, a lack of quantitative environmental data in many gut microbiome (GM) studies of wild animals limits our ability to pinpoint mechanisms through which habitat disturbance affects the GM. Here, we examine the impact of anthropogenic habitat disturbance on the diet and GM of the Critically Endangered black-and-white ruffed lemur (Varecia variegata editorum). We collected fecal samples and behavioral data from Varecia occupying habitats qualitatively categorized as primary forest, moderately disturbed forest, and heavily disturbed forest. Results Varecia diet and GM composition differed substantially across sites. Dietary richness predicted GM richness across sites, and overall GM composition was strongly correlated to diet composition. Additionally, the consumption of three specific food items positively correlated to the relative abundances of five microbial strains and one microbial genus across sites. However, diet did not explain all of the GM variation in our dataset, and differences in the GM were detected that were not correlated with diet, as measured. Conclusions Our data suggest that diet is an important influence on the Varecia GM across habitats and thus could be leveraged in novel conservation efforts in the future. However, other factors such as contact with humans should also be accounted for. Overall, we demonstrate that quantitative data describing host habitats must be paired with GM data to better target the specific mechanisms through which environmental change affects the GM.

In recent decades Madagascar has experienced significant habitat loss and modification, with minimal understanding of how human land use practices have impacted the evolution of its flora and fauna. In light of ongoing and intensifying anthropogenic pressures, we seek new insight into mechanisms driving genetic variability on this island, using a Critically Endangered lemur species, the black-and-white ruffed lemur (Varecia variegata), as a test case. Here, we examine the relative influence of natural and anthropogenic landscape features that we predict will impose barriers to dispersal and promote genetic structuring across the species range. Using circuit theory, we model functional connectivity among 18 sampling localities using population-based genetic distance (FST). We optimized resistance surfaces using genetic algorithms and assessed their performance using maximum-likelihood population-effects mixed models. The best supported resistance model was a composite surface that included two anthropogenic features, habitat cover and distance to villages, suggesting that rapid land cover modification by humans has driven change in the genetic structure of wild lemurs. Primary conservation priority should be placed on mitigating further forest loss and connecting regions identified as having low dispersal potential to prevent further loss of genetic diversity and promote the survival of other moist forest specialists.

A variety of factors can affect the biodiversity of tropical mammal communities, but their relative importance and directionality remain uncertain. Previous global investigations of mammal functional diversity have relied on range maps instead of observational data to determine community composition. We test the effects of species pools, habitat heterogeneity, primary productivity and human disturbance on the functional diversity (dispersion and richness) of mammal communities using the largest standardized tropical forest camera trap monitoring system, the Tropical Ecology Assessment and Monitoring (TEAM) Network. We use occupancy values derived from the camera trap data to calculate occupancy-weighted functional diversity and use Bayesian generalized linear regression to determine the effects of multiple predictors. Mammal community functional dispersion increased with primary productivity, while functional richness decreased with human-induced local extinctions and was significantly lower in Madagascar than other tropical regions. The significant positive relationship between functional dispersion and productivity was evident only when functional dispersion was weighted by species' occupancies. Thus, observational data from standardized monitoring can reveal the drivers of mammal communities in ways that are not readily apparent from range map-based studies. The positive association between occupancy-weighted functional dispersion of tropical forest mammal communities and primary productivity suggests that unique functional traits may be more beneficial in more productive ecosystems and may allow species to persist at higher abundances.

Species with greater expression of fission-fusion dynamics show greater variability in the size, composition, and cohesion of subgroups over time. This may allow their adjustment to local environmental, social, and demographic conditions. We tested which environmental and social factors influenced subgroup size in one such species, the black-and-white ruffed lemur (Varecia variegata) at two sites within a fragmented forest landscape. Using instantaneous focal sampling at 15-min intervals, we collected data on subgroup size and composition, fruit and flower availability, and location. We also collected biweekly data on site-wide fruit and flower availability. We used these data to test the influence of season, food availability, reproduction, and predation risk on adult subgroup size in this species. Ruffed lemur adults consistently formed significantly larger subgroups in times of lower site-wide fruit availability, during the wet season, and when one or more infants were present. There were differences between sites in the relationship between subgroup size and tree size, fruit patch size, and site-wide flower availability. Variables measuring indirect predation risk showed no significant relationship with subgroup size. These results emphasize the strong relationship between fission-fusion dynamics and spatial and temporal variation in food availability, as well as the importance of sociality in a species with communal care of infants. Fission-fusion dynamics may serve as an evolutionary strategy to adapt to the unpredictable and sometimes harsh environmental conditions of Madagascar and may facilitate the persistence of communities of this critically endangered lemur despite widespread anthropogenic habitat modification. Fission-fusion dynamics (the joining and separating of subgroups within a larger group of animals) may allow species to adjust social benefits to changing environmental conditions. This study examines the underlying ecological and social factors that might influence fission-fusion dynamics in black-and-white ruffed lemurs. Subgroup size in this species was strongly related to food availability, though not always in the direction expected. This suggests that the relationship between food availability and sociality changes when food availability reaches very low levels. Additionally, infant presence was linked to larger adult subgroups, indicating a connection between fission-fusion behavior and the cooperative rearing of offspring seen in this species. Relationships between subgroup size and some environmental variables differed between sites, emphasizing the flexibility of grouping patterns in this species and indicating that local conditions may play a large role in the expression of fission-fusion dynamics.

Biological invasions can represent important threats to endemic species, including those within the invaders’ food webs. The Asian common toad (Duttaphrynus melanostictus) was introduced to Madagascar in 2011. This introduction presents a potentially dangerous prey item to a relatively naive, highly diverse endemic carnivore fauna. Using a multivariate niche modeling approach (background test), we assessed the predicted niche overlap between D. melanostictus and six endemic carnivores in eastern Madagascar. The overlap between this potential prey and predators was assessed on four environmental niche axes: temperature, precipitation, vegetation cover and elevation. Our results showed a mixture of niche overlap and divergence between D. melanostictus and the six carnivores for environmental axes tested. There was significant overlap with five of the carnivores on temperature and NDVI axes. On the precipitation axis, there was significant overlap between D. melanostictus with two species. Our results suggested that wide-ranging, locally rare carnivores may overlap extensively with D. melanostictus. The six carnivores that inhabit the eastern rainforest of Madagascar will likely share multiple, niche axes with this novel potential prey item. Species that eat the non-native common toad and are susceptible to its toxins are at conservation risk because their populations may not be robust enough to adapt quickly to this threat. We advocate closely monitoring these emerging interactions and suggest a preemptive conservation strategy for carnivores potentially at risk.

Edge effects are among the most significant consequences of forest fragmentation. Therefore, understanding the impacts of edge creation on biodiversity is crucial for forest management and biological conservation. In this study, we used trait‐based and phylogenetic approaches to examine the effects of fragmentation on components of diversity and above‐ground biomass of rainforest tree communities in Madagascar in forest edge vs. interior habitats. Tree communities in forest edges showed lower phylogenetic diversity relative to those in interior habitats, suggesting that some clades may be more vulnerable to environmental filtering than others. Functional diversity was also significantly lower on the edge for productivity traits, but not for dispersal traits. Tree communities in the forest edge showed higher divergence of dispersal traits and lower divergence in productivity traits than expected, while functional diversity in interior forest did not differ from random expectations. This suggests that separate mechanisms affect productivity traits vs. dispersal traits in edge habitats. There was no significant difference in above‐ground biomass between edge and interior habitats, suggesting that edge effects have not yet negatively influenced the forest's potential for carbon storage. However, these changes may not have occurred yet, given the slow turnover of tree communities. Synthesis and applications. Our results highlight the role of edge effects in the erosion of functional and phylogenetic diversity of highly diverse tree communities. While above‐ground biomass did not appear to be affected by forest edge in our study, we suggest long‐term monitoring of forests for potential changes in ecosystem functioning. These findings also indicate the need to reduce edge creation and buffer existing edges for holistic biodiversity conservation.

Noninvasive sampling is an important development in population genetic monitoring of wild animals. Particularly, the collection of environmental DNA (eDNA) which can be collected without needing to encounter the target animal facilitates the genetic analysis of endangered species. One method that has been applied to these sample types is target capture and enrichment which overcomes the issue of high proportions of exogenous (nonhost) DNA from these lower quality samples. We tested whether target capture of mitochondrial DNA from sampled feeding traces of the aye‐aye, an endangered lemur species would yield mitochondrial DNA sequences for population genetic monitoring. We sampled gnawed wood where aye‐ayes excavate wood‐boring insect larvae from trees. We designed RNA probes complementary to the aye‐aye's mitochondrial genome and used these to isolate aye‐aye DNA from other nontarget DNA in these samples. We successfully retrieved six near‐complete mitochondrial genomes from two sites within the aye‐aye's geographic range that had not been sampled previously. Our method demonstrates the application of next‐generation molecular techniques to species of conservation concern. This method can likely be applied to alternative foraged remains to sample endangered species other than aye‐ayes.

An organism’s body size is intrinsically related to its metabolic requirements, life history profile, and ecological niche. Previous work in primates generally, and lemurs specifically, has shown that body size often correlates with ecological parameters related to temperature and energy availability in the environment, although other studies indicate the absence of any such patterns in lemurs. Here we test hypotheses that predict that body mass in Eulemur should covary with 1) overall food availability or resource seasonality and/or 2) temperature, i.e., Bergmann’s rule. We use data from 722 wild true lemurs to identify population-specific body mass for 27 populations representing 11 of the 12 described Eulemur species, and derive climatic data for each population from the WorldClim database. We use phylogenetic generalized least squares models to evaluate these hypotheses and find that body mass significantly negatively correlates with annual mean temperature and positively correlates with standard deviation of temperature, but does not significantly correlate with annual rainfall or number of dry months. These results indicate that body mass distribution across populations in Eulemur is consistent with Bergmann’s rule, but does not track resource seasonality as seen in other lemurs, e.g., Propithecus. We suggest that the fact that body mass in various lemur radiations correlates with different environmental variables may result in these patterns being obscured when such taxa are combined in a single analysis. This may help explain why some previous work has found little evidence of ecogeographical correlates with body mass across all Lemuriformes.

Summary In contrast to the majority of primates, which exhibit dedicated diurnality or nocturnality, all species of Eulemur are cathemeral. Colour vision, in particular, is strongly affected by the spectral composition and intensity of ambient light, and the impact of activity period on the evolution of primate colour vision is actively debated. We studied three groups of wild brown lemurs (Eulemur fulvus) in Ankarafantsika National Park, Madagascar, over a 1-year span. We also used non-invasive faecal DNA collection and analysis to study the opsin genes underlying the colour vision of 24 individuals. We quantified the colour and brightness of dietary fruits and modelled the chromaticity and discriminability of food objects to different visual phenotypes under daylight, twilight and moonlight conditions. We found that E. fulvus possesses routine dichromacy, unlike its congener E. flavifrons, for which polymorphic trichromacy has been reported. Our models suggest that dichromacy is well suited to the foraging ecology of E. fulvus. The performance of modelled dichromats and trichromats is comparable under nocturnal illuminants, and the luminance values of most diet items are detectable across light conditions. The trichromatic phenotype demonstrates a modest advantage under daylight conditions. Our results, taken together with reports of polymorphic trichromacy in E. flavifrons, suggest functional ecological variation in the visual system of the genus Eulemur. Interspecific phenotypic variation in the colour vision of a genus is both unexpected and instructive. Ecological differences between species of Eulemur could reveal thresholds for the origins of polymorphic trichromacy, which preceded the evolution of routine trichromatic vision in humans and other primates.

Endogenous selection is often implicated in the maintenance of stability of natural hybrid zones. Environmental conditions often vary across these zones, suggesting that local adaptation to ecological conditions could also play a role in this process. We used niche modeling to investigate these alternatives in a hybrid zone between two species of brown lemur (Eulemur rufifrons and E. cinereiceps) in southeastern Madagascar. We produced ecological niche models (ENMs) for parental and hybrid populations and compared values of niche overlap to null expectations using identity and background tests. All three taxonomic groups had nonequivalent ENMs with limited spatial overlap, supporting a role for niche divergence and local adaptation in the maintenance of this zone. However, values of niche overlap between ENMs were not greater than null expectations controlling for background environmental differences. These results could suggest that taxa in this hybrid zone inhabit portions of their environments that are more similar to their backgrounds, i.e., niche conservatism. Nevertheless, we did find evidence of niche divergence when using background tests that examined environmental variables separately. Although we could not rule out models indicating selection against hybrids, most lines of evidence were consistent with predictions for the bounded superiority model of hybrid zone stability. This study thus provides support that exogenous, environmental selection may be responsible for maintaining the hybrid zone, and may be implicated in the evolutionary divergence of these taxa.

The northern sportive lemur, Lepilemur septentrionalis, faces imminent danger of extinction, more so than any other lemur in Madagascar. The population estimates for this sportive lemur remain unknown because of habitat loss and ongoing human encroachment, but they are unlikely to number more than a few hundred individuals. We present the results of extensive surveys conducted in 2010, 2011 and 2012 of known habitat, the Sahafary and Analalava classified forests, and confirm the species designation of the sportive lemur observed in Montagne des Francais in 2007. Six L. septentrionalis individuals were examined in Sahafary in 2011, along with eight individuals during the 2010 and 2011 expeditions to Montagne des Francais. A July 2012 survey in extended forest fragments of Montagne des Francais identified another 10 individuals. Surveys of the Analalava forest in 2011 detected no northern sportive lemurs, despite documenting their presence in 2005. One individual was recorded in the July 2012 survey. Although the morphological data of the sportive lemurs at Montagne des Francais was comparable to that of Sahafary, the sportive lemur at Montagne des Francais was subsequently verified as L. septentrionalis with mitochondrial DNA D-loop sequence data analyses. The confirmation of the northern sportive lemur at Montagne des Francais is significant since it establishes additional habitat for this species. However, sustained human encroachment from Antsiranana continues to finance the production of charcoal and collection of sand; activities that are threatening this population. Habitat loss and hunting continue to be the principal threats to the long-term survival of the northern sportive lemur. With only 19 known individuals, we urge immediate conservation action for this Critically Endangered species.

Studies of hybrid zones can inform our understanding of reproductive isolation and speciation. Two species of brown lemur (Eulemur rufifrons and E. cinereiceps) form an apparently stable hybrid zone in the Andringitra region of south-eastern Madagascar. The aim of this study was to identify factors that contribute to this stability. We sampled animals at 11 sites along a 90-km transect through the hybrid zone and examined variation in 26 microsatellites, the D-loop region of mitochondrial DNA, six pelage and nine morphological traits; we also included samples collected in more distant allopatric sites. Clines in these traits were noncoincident, and there was no increase in either inbreeding coefficients or linkage disequilibrium at the centre of the zone. These results could suggest that the hybrid zone is maintained by weak selection against hybrids, conforming to either the tension zone or geographical selection-gradient model. However, a closer examination of clines in pelage and microsatellites indicates that these clines are not sigmoid or stepped in shape but instead plateau at their centre. Sites within the hybrid zone also occur in a distinct habitat, characterized by greater seasonality in precipitation and lower seasonality in temperature. Together, these findings suggest that the hybrid zone may follow the bounded superiority model, with exogenous selection favouring hybrids within the transitional zone. These findings are noteworthy, as examples supporting the bounded superiority model are rare and may indicate a process of ecologically driven speciation without geographical isolation.

Previous work in primates has shown that body size often covaries with ecological parameters related to resource or energy availability in the environment. This relationship may differ for males and females as access to resources has greater importance for reproductive success in females. We test the hypotheses that (1) female body mass may be more tightly constrained than male body mass by ecological variables, and (2) female body mass may respond more strongly than male body mass to changes in ecological variables (i.e., population-specific female mass may vary more across an ecological gradient than male mass). Specifically, we investigate the relationship between climatic variables and sex-specific body mass in Propithecus, a genus in which species-specific body mass has already been demonstrated to covary significantly with climatic variables. Data from 733 wild sifakas are used to identify sex-specific body mass for 27 populations representing all nine described sifaka species, and climatic data for each population are derived from the WorldClim database. We use phylogenetic generalized least squares models to demonstrate that body mass in both sexes is significantly correlated with annual rainfall and number of dry months. Furthermore, coefficients of determination are always higher for female models, and coefficients for each climatic variable are higher for females in all significant models. These results support the two hypotheses tested, indicating that ecological forces can have a greater impact on female mass than on male mass in primates.

Land use in Madagascar has resulted in extensive deforestation and forest fragmentation. Endemic species, such as the black-and-white ruffed lemur (Varecia variegata), may be vulnerable to habitat fragmentation due to patchy geographic distributions and sensitivities to forest disturbance. We tested for genetic differentiation among black-and-white ruffed lemur groups in two sites in a large forest patch and three sites in smaller patches. We also investigated the relationship between the genetic diversity of populations and patch configuration (size and isolation), as well as the presence or absence of past genetic bottlenecks. We collected blood (n = 22 individuals) or fecal (n = 33) samples from lemurs and genotyped the extracted DNA for 16 polymorphic microsatellites. Bayesian cluster analysis and FST assigned individuals to three populations: Ranomafana (two sites in continuous forest), Kianjavato (two fragments separated by 60 m of non-forest), and Vatovavy (a single fragment, more isolated in time and space). Vatovavy showed significantly lower allelic richness than Ranomafana. Kianjavato also appeared to have lower allelic richness than Ranomafana, though the difference was not significant. Vatovavy was also the only population with a genetic bottleneck indicated under more than one mutation model and a significant FIS value, showing excess heterozygosity. These results indicate that a small geographic separation may not be sufficient for genetic differentiation of black-and-white ruffed lemur populations and that patch size may influence the rapidity with which genetic diversity is lost following patch isolation.

Knowledge of both population size and genetic diversity is critical for assessing extinction risk but few studies include concurrent estimates of these two components of population biology. We conducted an investigation of population density and size, and genetic variation and past demographic events, of the Endangered grey-headed lemurEulemur cinereicepsin south-east Madagascar. We estimated lemur density using line-transect surveys and used satellite imagery to calculate forest fragment area in three localities. We collected tissue samples from 53 individuals and used 26 polymorphic microsatellite loci to obtain measures of population structure (divergence and diversity) across these localities. We tested the probability of past bottleneck events using three models. Contrary to expectation, there were no significant differences in population density across localities. Genetic diversity decreased, but not significantly, with decreasing habitat area and population size. We found a higher likelihood of past bottleneck events in the fragmented coastal populations. The low population size and prior decline in diversity in coastal patches are consistent with their isolation, anthropogenic disturbance, and exposure to cyclone activity. The similarities in the estimates of density between continuous and fragmented sites may indicate recent population growth in the fragments but these populations nevertheless remain at risk from reduced levels of genetic variation. These patterns should be confirmed with more extensive sampling across the limited range ofE. cinereiceps.

McConnell and Kull question whether the current forest habitat represents “only 10 to 20% of Madagascar's original forest cover.” We agree that it would have been more prudent to replace “original forest cover” with “surface.” We also concur that there is palaeoecological evidence for

Madagascar's ecosystems are subject to high levels of anthropogenic disturbance and stochastic events, including cyclones. We investigated the abundance of gray-headed lemurs (Eulemur cinereiceps) and vegetation structure in the fragmented forest of Manombo from 1995 to 2007, including 10 yr following Cyclone Gretelle in January 1997. We predicted that the density of this arboreal, frugivorous lemur would be similar in the pre- and post-cyclone intervals only if tree measures demonstrate trends toward recovery in the post-cyclone period. Initial impacts included severe damage to over 60 percent of trees. After 10 yr, all vegetation metrics except for stem density remained low relative to the pre-cyclone period, including dbh, height, and basal area. To investigate vegetation changes separately from cyclone effects, we compared forest structure in the pre-cyclone period alone. Basal area declined but dbh and stem density did not vary between 1995 and 1997; thus, anthropogenic activities or other factors did not consistently alter forest structure in this 2-yr period. Subsequent changes may be linked to cyclone response, presumably in synergy with human disturbance. Contrary to predictions, recent gray-headed lemur population densities were nearly identical to those recorded in 1995 (13.5 ± 3.2 vs. 13.6 ± 6.4 individuals/km 2 , respectively). Lemur populations may have remained stable or declined initially and then recovered in the last 10 yr. Life history and ecological adaptations may explain their resistance or resilience when faced with habitat change. Recent models suggest that lemurs have evolved in response to unpredictable environmental conditions. Such environmental variability may increase with projected climate change.

The wet tropical forests in Madagascar have endemic dung beetles that have radiated for tens of millions of years using a limited range of resources produced by the species-poor mammalian fauna. Beetles were trapped in two wet-forest localities over 4 years (6407 trap nights, 18,869 individuals). More limited data for six other local communities were used to check the generality of the results. Local communities are relatively species poor (around 30 species) in comparison with wet-forest-inhabiting dung beetle communities elsewhere in the tropics (typically 50 or more species). The species belong to only two tribes, Canthonini and Helictopleurina (Oniticellini), which have evolved, exceptionally for dung beetle tribes, completely nocturnal versus diurnal diel activities, respectively. Patterns in the elevational occurrence, body size and resource use suggest that interspecific competition restricts the numbers of locally coexisting species exploiting the limited range of resources that are available. On the other hand, regional turnover in the species composition is exceptionally high due to a large number of species with small geographical ranges, yielding a very large total fauna of dung beetles in Madagascar (>250 species). Apart from exceptionally low local (alpha) diversity and high beta diversity, the Malagasy dung beetle communities are ecologically distinctive from comparable communities in other tropical regions in having high numerical dominance of the most abundant species, small average body size and low degree of resource specialization.

Prolemur simus (the greater bamboo lemur) is the most abundant lemur in the northern subfossil sites of Madagascar. Living populations still persist, but in low numbers within a diminished range, making it one of the most critically endangered lemurs. Over the past twenty years scientists have searched the south- and central-eastern rain forests of Madagascar. Despite surveys that encompass over 500 km2, less than 75 animals have been found, with a recent total count of 60. More encouraging is that in 2007 two new sites containing P. simus were found: Mahasoa an unprotected 150 ha fragment east of the Ranomafana/Andringitra corridor (17 P. simus), and Torotorofotsy, a RAMSAR site near Andasibe (∼16 P. simus). Prolemur simus is a bamboo specialist with a patchy geographic distribution, which may be driven by the distribution of one or two bamboo species. Home ranges are large, group size has been observed to be from four to 26 individuals, and localities may be spaced hundreds of kilometers apart...

Although appearing in the literature as early as 1890, the brown lemur form Eulemur cinereiceps has recently resurfaced as a potentially valid taxon, distinct from neighboring, presumably closely related species such as white-collared lemurs (Eulemur albocollaris). We propose two scenarios for the potential separation of E. cinereiceps and E. albocollaris: (1) coastal and interior populations represent two distinct taxa and (2) the coastal population north of the Manampatrana River (the locality for purported museum specimens of E. cinereiceps) represents a distinct species from E. albocollaris found south of the river and in the interior escarpment forests. We tested these hypotheses using data from ground surveys and genetic sampling. Surveys were conducted in coastal forest fragments both north and south of the Manampatrana River in July–August 2006. Genetic samples were collected at two coastal sites and one interior forest. We used maximum parsimony, maximum likelihood, and neighbor-joining analyses on mitochondrial DNA regions to determine if populations from different sites clustered into diagnosable clades. Results from field surveys confirmed the presence of forms commonly referred to as E. albocollaris at the two southern coastal forests; no consistent phenotypic differences across sites were observed. All genetic analyses yielded identical results: coastal and interior populations do not cluster into separate groups, thus rejecting the first hypothesis. Eulemur species and all other day-active lemurs have apparently been extirpated from coastal forests north of the Manampatrana. Owing to the absence of lemurs from the northern coastal localities, we could not conclusively support or reject the second scenario. However, based on examination of the original plates and museum specimens, as well as the biogeographic patterns typical of this region, we strongly suspect that all populations from this area belong to a single species. We conclude with remarks regarding the apparent priority of E. cinereiceps for this taxon. Am. J. Primatol. 70:372–385, 2008. © 2007 Wiley-Liss, Inc.

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

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

Lemurs are among the world's most threatened mammals. The critically endangered black-and-white ruffed lemur (Varecia variegata), in particular, has recently experienced rapid population declines due to habitat loss, ecological sensitivities to habitat degradation, and extensive human hunting pressure. Despite this, a recent study indicates that ruffed lemurs retain among the highest levels of genetic diversity for primates. Identifying how this diversity is apportioned and whether gene flow is maintained among remnant populations will help to diagnose and target conservation priorities. We sampled 209 individuals from 19 sites throughout the remaining V. variegata range. We used 10 polymorphic microsatellite loci and ∼550 bp of mtDNA sequence data to evaluate genetic structure and population dynamics, including dispersal patterns and recent population declines. Bayesian cluster analyses identified two distinct genetic clusters, which optimally partitioned data into populations occurring on either side of the Mangoro River. Localities north of the Mangoro were characterized by greater genetic diversity, greater gene flow (lower genetic differentiation) and higher mtDNA haplotype and nucleotide diversity than those in the south. Despite this, genetic differentiation across all sites was high, as indicated by high average F ST (0.247) and ΦST (0.544), and followed a pattern of isolation-by-distance. We use these results to suggest future conservation strategies that include an effort to maintain genetic diversity in the north and restore connectivity in the south. We also note the discordance between patterns of genetic differentiation and current subspecies taxonomy, and encourage a re-evaluation of conservation management units moving forward.

Four forest areas were censused in southeastern Madagascar from June-August 1995 to estimate local population densities and habitat conditions for two threatened subspecies of brown lemur (Eulemur fulvus collaris and Eulemur fulvus albocollaris). Survey transects varied in length (1-3.5 km) and in surveillance frequency (three to seven times). Additional test surveys were conducted at the Parc National de Ranomafana to compare transect methods in an area with known population densities of Eulemur fulvus. Based on these tests, we demonstrate that the use of existing trails for transects can result in a close estimate of local population size, although more replications and longer transects increase precision. Results from regional surveys indicate considerably smaller population densities for E. f. albocollaris (0.086 animals/ha). In contrast, E. f. collaris densities were relatively high (.107 animals/ha) at Midongy-Sud. We also noted variation among sites in the density of lianas, which was positively correlated with local population density (a possible indication of habitat degradation). More generally, habitats in E. f. albocollaris's range suffered from fragmentation, reduction in forest area, logging, and potentially greater hunting pressure. Based on these results, it is apparent that more immediate steps are necessary to preserve E. f. albocollaris populations and habitats.

We performed a population genomics study of the aye-aye, a highly specialized nocturnal lemur from Madagascar. Aye-ayes have low population densities and extensive range requirements that could make this flagship species particularly susceptible to extinction. Therefore, knowledge of genetic diversity and differentiation among aye-aye populations is critical for conservation planning. Such information may also advance our general understanding of Malagasy biogeography, as aye-ayes have the largest species distribution of any lemur. We generated and analyzed whole-genome sequence data for 12 aye-ayes from three regions of Madagascar (North, West, and East). We found that the North population is genetically distinct, with strong differentiation from other aye-ayes over relatively short geographic distances. For comparison, the average F ST value between the North and East aye-aye populations—separated by only 248 km—is over 2.1-times greater than that observed between human Africans and Europeans. This finding is consistent with prior watershed- and climate-based hypotheses of a center of endemism in northern Madagascar. Taken together, these results suggest a strong and long-term biogeographical barrier to gene flow. Thus, the specific attention that should be directed toward preserving large, contiguous aye-aye habitats in northern Madagascar may also benefit the conservation of other distinct taxonomic units. To help facilitate future ecological- and conservation-motivated population genomic analyses by noncomputational biologists, the analytical toolkit used in this study is available on the Galaxy Web site.

Madagascar is a global biodiversity hotspot, with high levels of endemism coupled with a high degree of anthropogenic disturbance. Lemurs are important in maintaining the island’s ecosystems. We examine the primary and emerging threats to lemurs, present a brief history of the conservation efforts implemented to preserve Malagasy ecosystems, and discuss the future direction of and prospects for conservation in Madagascar.

Biodiversity plays an integral role in the livelihoods of subsistence-based forest-dwelling communities and as a consequence it is increasingly important to develop quantitative approaches that capture not only changes in taxonomic diversity, but also variation in natural resources and provisioning services. We apply a functional diversity metric originally developed for addressing questions in community ecology to assess utilitarian diversity of 56 forest plots in Madagascar. The use categories for utilitarian plants were determined using expert knowledge and household questionnaires. We used a null model approach to examine the utilitarian (functional) diversity and utilitarian redundancy present within ecological communities. Additionally, variables that might influence fluctuations in utilitarian diversity and redundancy--specifically number of felled trees, number of trails, basal area, canopy height, elevation, distance from village--were analyzed using Generalized Linear Models (GLMs). Eighteen of the 56 plots showed utilitarian diversity values significantly higher than expected. This result indicates that these habitats exhibited a low degree of utilitarian redundancy and were therefore comprised of plants with relatively distinct utilitarian properties. One implication of this finding is that minor losses in species richness may result in reductions in utilitarian diversity and redundancy, which may limit local residents' ability to switch between alternative choices. The GLM analysis showed that the most predictive model included basal area, canopy height and distance from village, which suggests that variation in utilitarian redundancy may be a result of local residents harvesting resources from the protected area. Our approach permits an assessment of the diversity of provisioning services available to local communities, offering unique insights that would not be possible using traditional taxonomic diversity measures. These analyses introduce another tool available to conservation biologists for assessing how future losses in biodiversity will lead to a reduction in natural resources and provisioning services from forests.

The most threatened mammal group on Earth, Madagascar's five endemic lemur families (lemurs are found nowhere else) ( 1 ), represent more than 20% of the world's primate species and 30% of family-level diversity. This combination of diversity and uniqueness is unmatched by any other country—remarkable considering that Madagascar is only 1.3 to 2.9% the size of the Neotropics, Africa, or Asia, the other three landmasses where nonhuman primates occur. But lemurs face extinction risks driven by human disturbance of forest habitats. We discuss these challenges and reasons for hope in light of site-specific, local actions proposed in an emergency conservation action plan ( 2 ).

Ecosystems services are threatened by the rapid degradation of tropical rainforests. In light of these threats, questions remain about how societies on the forest fringe who depend on provisioning services affect plant functional traits. This study assessed the relationship between plant functional traits, forest-dependent societies and provisioning ecosystem services along a forest–agriculture matrix gradient in tropical humid forests of Madagascar. Data were collected for six functional traits and six provisioning services. We evaluated functional diversity (FD) and utilitarian diversity (FD of provisioning services) along disturbance gradients. We also determined the traits most susceptible to loss along the gradient as well as the relationship between functional traits and provisioning services. The results showed that FD, utilitarian diversity and species richness decreased significantly across all modified habitats. There was a distinct suite of traits absent from intensely used habitats and those same traits were associated with the two most important provisioning services in the region (firewood and construction). The activities of people living on the forest fringe seem to be a strong selective force on trait loss in plant communities, which in turn will influence future species assembly and trait diversity and distribution. Moreover, this study suggests that it is possible to predict trait loss from plant communities in forests where degradation is mediated primarily through subsistence agriculture and resource extraction. Conservation efforts should recognize that forest degradation and deforestation are contextually specific, determined mostly by people’s efforts to maintain their basic livelihood, and therefore necessitate local-scale interventions that feed into landscape-scale policy initiatives.