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

While 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, nonseasonal food resource and be a key factor for persistence during the initial stage of the recolonization.

Stuck in fragments: Population genetics of the Endangered collared brown lemur Eulemur collaris in the Malagasy littoral forest.

OBJECTIVES: The Endangered collared brown lemur (Eulemur collaris) is the largest primate living in the littoral forest of southeastern Madagascar, a top priority habitat for biodiversity conservation on the island. Because this lemur is a key seed-disperser, an evaluation of the structure and connectivity of the populations surviving in the forest fragments is urgently needed to guide conservation plans. MATERIALS AND METHODS: Genetic variability at autosomal microsatellites and mitochondrial DNA was investigated in a total of 49 collared brown lemurs sampled by non-invasive methods in three littoral forest fragments and in the nearby lowland humid forest. 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.

Challenges of next-generation sequencing in conservation management: Insights from long-term monitoring of corridor effects on the genetic diversity of mouse lemurs in a fragmented landscape.

Long-term genetic monitoring of populations is essential for efforts aimed at preserving genetic diversity of endangered species. Here, we employ a framework of long-term genetic monitoring to evaluate the effects of fragmentation and the effectiveness of the establishment of corridors in restoring population connectivity and genetic diversity of mouse lemurs Microcebus ganzhorni. To this end, we supplement estimates of neutral genetic diversity with the assessment of adaptive genetic variability of the major histocompatibility complex (MHC). In addition, we address the challenges of long-term genetic monitoring of functional diversity by comparing the genotyping performance and estimates of MHC variability generated by single-stranded conformation polymorphism (SSCP)/Sanger sequencing with those obtained by high-throughput sequencing (next-generation sequencing [NGS], Illumina), an issue that is particularly relevant when previous work serves as a baseline for planning management strategies that aim to ensure the viability of a population. We report that SSCP greatly underestimates individual diversity and that discrepancies in estimates of MHC diversity attributable to the comparisons of traditional and NGS genotyping techniques can influence the conclusions drawn from conservation management scenarios. Evidence of migration among fragments in Mandena suggests that mouse lemurs are robust to the process of fragmentation and that the effect of corridors is masked by ongoing gene flow. Nonetheless, results based on a larger number of shared private alleles at neutral loci between fragment pairs found after the establishment of corridors in Mandena suggest that gene flow is augmented as a result of enhanced connectivity. Our data point out that despite low effective population size, M. ganzhorni maintains high individual heterozygosity at neutral loci and at MHC II DRB gene and that selection plays a predominant role in maintaining MHC diversity. These findings highlight the importance of long-term genetic monitoring in order to disentangle between the processes of drift and selection maintaining adaptive genetic diversity in small populations.

The Use of an Invasive Species Habitat by a Small Folivorous Primate: Implications for Lemur Conservation in Madagascar.

The lemurs of Madagascar are among the most threatened mammalian taxa in the world, with habitat loss due to shifting cultivation and timber harvest heavily contributing to their precarious state. Deforestation often leads to fragmentation, resulting in mixed-habitat matrices throughout a landscape where disturbed areas are prone to invasion by exotic plants. Our study site, the Mandena littoral forest (southeast Madagascar), is a matrix of littoral forest, littoral swamp, and Melaleuca swamp habitats. Here, Melaleuca quinquenervia has invaded the wetland ecosystem, creating a mono-dominant habitat that currently provides the only potential habitat corridor between forest fragments. We sought to understand the role of this invasive Melaleuca swamp on the behavioral ecology of a threatened, small-bodied folivore, the southern bamboo lemur (Hapalemur meridionalis). We collected botanical and behavioral data on four groups of H. meridionalis between January and December 2013. Our results confirm Melaleuca swamp as an important part of their home range: while lemurs seasonally limited activities to certain habitats, all groups were capable of utilizing this invasive habitat for feeding and resting. Furthermore, the fact that Hapalemur use an invasive plant species as a dispersal corridor increases our knowledge of their ecological flexibility, and may be useful in the conservation management of remaining threatened populations.

Phylogenetic relationships between Hapalemur species and subspecies based on mitochondrial DNA sequences.

BACKGROUND: Phylogenetic relationships of the genus Hapalemur remains controversial, particularly within the Hapalemur griseus species group. In order to obtain more information on the taxonomic status within this genus, and particularly in the cytogenetic distinct subspecies group of Hapalemur griseus, 357 bp sequence of cytochrome b and 438 bp of 12S mitochondrial DNAs were analyzed on a sample of animals captured in areas extending from the north to the south-east of Madagascar. This sample covers all cytogenetically defined types recognized of the genus Hapalemur. RESULTS: Phylogenetic trees and distances analyses demonstrate a first emergence of Hapalemur simus followed by H. aureus which is the sister clade of the H. griseus subspecies. Hapalemur griseus is composed of 4 subspecies separated into two clades. The first contains H. g. griseus, H. g. alaotrensis and H. g. occidentalis. The second consists of H. g. meridionalis. A new chromosomal polymorphic variant from the region of Ranomafana, H. griseus ssp, has been analysed and was found in both clades. CONCLUSIONS: Our results support the raising of H. g. meridionalis to the specific rank H. meridionalis, while neither cytogenetic nor molecular evidences support the raising of H. g. alaotrensis to a species rank despite its morphological characteristics. The new cytotype H. g. ssp which has been previously characterized by cytogenetic studies contains animals clustering either with the group of Hapalemur griseus griseus or with that of Hapalemur meridionalis. This suggests the existence of an ancestral polymorphism or an introgression of mitochondrial DNA between subspecies.

Habitat degradation and seasonality affect physiological stress levels of Eulemur collaris in littoral forest fragments.

The littoral forest on sandy soil is among the most threatened habitats in Madagascar and, as such, it represents a hot-spot within a conservation hot-spot. Assessing the health of the resident lemur fauna is not only critical for the long-term viability of these populations, but also necessary for the future re-habilitation of this unique habitat. Since the Endangered collared brown lemur, Eulemur collaris, is the largest seed disperser of the Malagasy south-eastern littoral forest its survival in this habitat is crucial. In this study we compared fecal glucocorticoid metabolite (fGCM) levels, a measure of physiological stress and potential early indicator of population health, between groups of collared brown lemurs living in a degraded forest fragment and groups occurring in a more preserved area. For this, we analysed 279 fecal samples collected year-round from 4 groups of collared brown lemurs using a validated 11-oxoetiocholanolone enzyme immunoassay and tested if fGCM levels were influenced by reproductive stages, phenological seasons, sex, and habitat degradation. The lemurs living in the degraded forest had significantly higher fGCM levels than those living in the more preserved area. In particular, the highest fGCM levels were found during the mating season in all animals and in females during gestation in the degraded forest. Since mating and gestation are both occurring during the lean season in the littoral forest, these results likely reflect a combination of ecological and reproductive pressures. Our findings provide a clear indication that habitat degradation has additive effects to the challenges found in the natural habitat. Since increased stress hormone output may have long-term negative effects on population health and reproduction, our data emphasize the need for and may add to the development of effective conservation plans for the species.

Extinction risks and the conservation of Madagascar's reptiles.

BACKGROUND: An understanding of the conservation status of Madagascar's endemic reptile species is needed to underpin conservation planning and priority setting in this global biodiversity hotspot, and to complement existing information on the island's mammals, birds and amphibians. We report here on the first systematic assessment of the extinction risk of endemic and native non-marine Malagasy snakes, lizards, turtles and tortoises. METHODOLOGY/PRINCIPAL FINDINGS: Species range maps from The IUCN Red List of Threatened Species were analysed to determine patterns in the distribution of threatened reptile species. These data, in addition to information on threats, were used to identify priority areas and actions for conservation. Thirty-nine percent of the data-sufficient Malagasy reptiles in our analyses are threatened with extinction. Areas in the north, west and south-east were identified as having more threatened species than expected and are therefore conservation priorities. Habitat degradation caused by wood harvesting and non-timber crops was the most pervasive threat. The direct removal of reptiles for international trade and human consumption threatened relatively few species, but were the primary threats for tortoises. Nine threatened reptile species are endemic to recently created protected areas. CONCLUSIONS/SIGNIFICANCE: With a few alarming exceptions, the threatened endemic reptiles of Madagascar occur within the national network of protected areas, including some taxa that are only found in new protected areas. Threats to these species, however, operate inside and outside protected area boundaries. This analysis has identified priority sites for reptile conservation and completes the conservation assessment of terrestrial vertebrates in Madagascar which will facilitate conservation planning, monitoring and wise-decision making. In sharp contrast with the amphibians, there is significant reptile diversity and regional endemism in the southern and western regions of Madagascar and this study highlights the importance of these arid regions to conserving the island's biodiversity.

Better few than hungry: flexible feeding ecology of collared lemurs Eulemur collaris in littoral forest fragments.

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.