1. 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. 2. 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. 3. 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. 4. 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. 5. 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.
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Canine rabies causes an estimated 60,000 human deaths per year, but these deaths are preventable through post-exposure prophylaxis of people and vaccination of domestic dogs. Dog vaccination campaigns targeting 70% of the population are effective at interrupting transmission. Here, we report on lessons learned during pilot dog vaccination campaigns in the Moramanga District of Madagascar. We compare two different vaccination strategies: a volunteer-driven effort to vaccinate dogs in two communes using static point vaccination and continuous vaccination as part of routine veterinary services. We used dog age data from the campaigns to estimate key demographic parameters and to simulate different vaccination strategies. Overall, we found that dog vaccination was feasible and that most dogs were accessible to vaccination. The static-point campaign achieved higher coverage but required more resources and had a limited geographic scope compared to the continuous delivery campaign. Our modeling results suggest that targeting puppies through community-based vaccination efforts could improve coverage. We found that mass dog vaccination is feasible and can achieve high coverage in Madagascar; however, context-specific strategies and an investment in dog vaccination as a public good will be required to move the country towards elimination.
Rapid deforestation has fragmented habitat across the landscape of Madagascar. To determine the effect of fragmentation on seed banks and the potential for forest regeneration, we sampled seed viability, density and diversity in 40 plots of 1 m 2 in three habitat types: forest fragments, the near edge of continuous forest, and deforested savanna in a highly fragmented dry deciduous forest landscape in northwestern Madagascar. While seed species diversity was not different between forest fragments and continuous forest edge, the number of animal-dispersed seeds was significantly higher in forest fragments than in continuous forest edge, and this pattern was driven by a single, small-seeded species. In the savanna, seeds were absent from all but three of the 40 plots, indicating that regeneration potential is low in these areas. Several pre-and post-dispersal biotic and abiotic factors, including variation in the seed predator communities and edge effects could explain these findings. Understanding the extent to which seed dispersal and seed banks influence the regeneration potential of fragmented landscapes is critical as these fragments are the potential sources of forest expansion and re-connectivity.Abstract in French is available with online material.
Human–wildlife conflicts are increasing in number and intensity making conflict mitigation and coexistence a top priority for wildlife conservation. Domesticated dogs (Canis lupus familiaris) can mitigate or exacerbate human–wildlife conflict leading to positive and negative impacts on both humans and wildlife. However, the human–dog–wildlife interface is not well understood, particularly in biodiversity hot spots. Madagascar is a tropical biodiversity hot spot with many rare and threatened species of high conservation concern. Here we assess wildlife predation by free‐roaming dogs in communities surrounding Andasibe–Mantadia and Ranomafana National Parks in eastern Madagascar using surveys of dog owners living adjacent to protected areas. Nearly half of survey respondents reported that their dog(s) had killed wildlife. Dogs that spent more time away from home, that traveled to the forest more frequently, that had killed domestic livestock, and that were owned for hunting were more likely to have killed wildlife. Dogs that were fed were approximately 20% less likely to have killed wildlife than dogs that were not fed. Keeping dogs restrained more often and providing food are therefore likely to reduce wildlife predation by dogs provided these are socially acceptable options. Additionally, we found spatial variation in wildlife predation by dogs both between and within our two study regions. These results can help conservation organizations develop targeted, effective interventions appropriately tailored to the local context and prioritize specific areas with higher wildlife predation by dogs.
Abstract in French is available with online material.
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