Life in a fragment: Evolution of foraging strategies of translocated collared brown lemurs, Eulemur collaris, over an 18-year period

Effects of forest fragmentation on the dietary ecology and activity of a nocturnal lemur community in North West Madagascar

Deforestation and habitat fragmentation is the primary threat to primate populations. The primates that live within degraded and anthropogenically disturbed habitats typical of fragmented landscapes have to cope with lower availability of resources in comparison to primates in continuous, undisturbed forests. While some species are sensitive to forest fragmentation, some evidence exists to suggest that primates can alter their behavior and adapt to such changes, which enables their survival in suboptimal habitat. In this study, we assessed how forest fragmentation and its associated edge-effects impact the feeding ecology and activity levels of a nocturnal primate community in the Sahamalaza-Iles Radama National Park, North West Madagascar. From March 06, 2019 to May 17, 2022, we collected data on tree and invertebrate phenology at our study site, and feeding ecology and activity for 159 lemur individuals from four species. Fruit and flower availability varied significantly between continuous and fragmented forest, and between forest core and edge areas, with continuous forest exhibiting higher continuous fruit and flower availability. Lemur feeding ecology varied significantly too, as the feeding niches of all four species were significantly different between continuous and fragmented forest and between core and edge areas. However, lemur activity levels were mostly consistent among all forest areas. The results of this study suggest that nocturnal lemurs are able to adapt their dietary ecology in response to the available food sources within their habitat. Due to this flexible ecology and dietary plasticity, the lemurs do not need to significantly alter their behavior in different environments to fulfill their dietary needs. While nocturnal lemurs demonstrate adaptability and flexibility to degraded habitat, it is unclear how far this plasticity will stretch considering that Madagascar's forests are still being cleared at an alarming rate. Urgent conservation action is therefore needed to ensure the future of lemur habitat.

A Pervasive History of Gene Flow in Madagascar's True Lemurs (Genus Eulemur)

In recent years, it has become widely accepted that interspecific gene flow is common across the Tree of Life. Questions remain about how species boundaries can be maintained in the face of high levels of gene flow and how phylogeneticists should account for reticulation in their analyses. The true lemurs of Madagascar (genus Eulemur, 12 species) provide a unique opportunity to explore these questions, as they form a recent radiation with at least five active hybrid zones. Here, we present new analyses of a mitochondrial dataset with hundreds of individuals in the genus Eulemur, as well as a nuclear dataset containing hundreds of genetic loci for a small number of individuals. Traditional coalescent-based phylogenetic analyses of both datasets reveal that not all recognized species are monophyletic. Using network-based approaches, we also find that a species tree containing between one and three ancient reticulations is supported by strong evidence. Together, these results suggest that hybridization has been a prominent feature of the genus Eulemur in both the past and present. We also recommend that greater taxonomic attention should be paid to this group so that geographic boundaries and conservation priorities can be better established.

Time-lagged effects of habitat fragmentation on terrestrial mammals in Madagascar

Biodiversity is severely threatened by habitat destruction. As a consequence of habitat destruction, the remaining habitat becomes more fragmented. This results in time-lagged population extirpations in remaining fragments when these are too small to support populations in the long term. If these time-lagged effects are ignored, the long-term impacts of habitat loss and fragmentation will be underestimated. We quantified the magnitude of time-lagged effects of habitat fragmentation for 157 nonvolant terrestrial mammal species in Madagascar, one of the biodiversity hotspots with the highest rates of habitat loss and fragmentation. We refined species' geographic ranges based on habitat preferences and elevation limits and then estimated which habitat fragments were too small to support a population for at least 100 years given stochastic population fluctuations. We also evaluated whether time-lagged effects would change the threat status of species according to the International Union for the Conservation of Nature (IUCN) Red List assessment framework. We used allometric relationships to obtain the population parameters required to simulate the population dynamics of each species, and we quantified the consequences of uncertainty in these parameter estimates by repeating the analyses with a range of plausible parameter values. Based on the median outcomes, we found that for 34 species (22% of the 157 species) at least 10% of their current habitat contained unviable populations. Eight species (5%) had a higher threat status when accounting for time-lagged effects. Based on 0.95-quantile values, following a precautionary principle, for 108 species (69%) at least 10% of their habitat contained unviable populations, and 51 species (32%) had a higher threat status. Our results highlight the need to preserve continuous habitat and improve connectivity between habitat fragments. Moreover, our findings may help to identify species for which time-lagged effects are most severe and which may thus benefit the most from conservation actions.

People, Lemurs and Utilitarian Plants of the Littoral Forests in Southeast Madagascar

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.

Using Utilitarian Plants for Lemur Conservation

Nature and species conservation often conflict with intensive natural resource or land use. Many protected areas are too small for long-term conservation of viable vertebrate populations, especially in Madagascar, and forests are subject to exploitation for a variety of natural resources. Trying to exclude people from the use of these resources has not been successful during economic, natural, or political crises or when human population growth outruns any development effort. People need economic and other benefits, and conservation measures have to account for these needs. We compiled native and introduced tree, shrub, and herbaceous species used by both people and native vertebrates for three regions, covering the domains of the dry, transitional, and humid forest of Madagascar. We carried out semistructured interviews and group discussions in 12 different villages in each study region in November 2017. People listed 139 utilitarian plant taxa. Our literature search revealed that 72 of these plant species and 13 genera used by people, were also used by 208 different terrestrial vertebrates including 58 lemur species. Application of the Forest Landscape Restoration approach with a combination of exotic and native plant species used by both people and animals could increase the economic value of restored forest habitats for people, thus providing incentives for forest conservation. Plantations of mixed utilitarian trees and shrubs could be integrated into agricultural landscapes. Among land-living vertebrates, lemurs seem to benefit most from this approach. These measures might contribute to a successful array of biodiversity conservation in anthropogenic landscapes.