1,720,972 research outputs found
Genetic and Demographic Consequences of a Rapid Reduction in Population Size in a Solitary Lemur (Mirza coquereli)
No full textPopulation bottlenecks as a result of habitat fragmentation or other anthropogenic disturbances are increasingly common, but their consequences remain poorly studied. We studied the genetic population structure of a solitary nocturnal primate, Mirza coquereli, to investigate the demographic history of a local subpopulation in Kirindy Forest, western Madagascar, which showed recent dramatic fluctuations in population size. Additionally, we sampled the surrounding forest area to assess the genetic structure of the local population on a broader geographical scale. Analyses of mitochondrial DNA (mtDNA) and microsatellites of 53 individuals revealed that a recent reduction and subsequent recovery in population size (demographic bottleneck) in the local subpopulation did not result in a genetic bottleneck. Moreover, predicted matrilineal clusters and male-biased dispersal could be confirmed on a broader geographical scale by mtDNA analysis, but not by microsatellite analyses. These results suggest that a re-colonization of the demographic bottlenecked area took place. This study contributes to our knowledge of the genetic structure of solitary mammals and primates in particular and illuminates behavioral mechanisms, such as sex-specific dispersal, that influence the genetic structure of populations. Furthermore, we showed that populations of solitary mammals are able to compensate drastic local demographic changes via migration if habitat continuity at an appropriate scale is given
On species delimitation: Yet another lemur species or just genetic variation?
No full textAbstract Background Although most taxonomists agree that species are independently evolving metapopulation lineages that should be delimited with several kinds of data, the taxonomic practice in Malagasy primates (Lemuriformes) looks quite different. Several recently described lemur species are based solely on evidence of genetic distance and diagnostic characters of mitochondrial DNA sequences sampled from a few individuals per location. Here we explore the validity of this procedure for species delimitation in lemurs using published sequence data. Results We show that genetic distance estimates and Population Aggregation Analysis (PAA) are inappropriate for species delimitation in this group of primates. Intra- and interspecific genetic distances overlapped in 14 of 17 cases independent of the genetic marker used. A simulation of a fictive taxonomic study indicated that for the mitochondrial D-loop the minimum required number of individuals sampled per location is 10 in order to avoid false positives via PAA. Conclusions Genetic distances estimates and PAA alone should not be used for species delimitation in lemurs. Instead, several nuclear and sex-specific loci should be considered and combined with other data sets from morphology, ecology or behavior. Independent of the data source, sampling should be done in a way to ensure a quantitative comparison of intra- and interspecific variation of the taxa in question. The results of our study also indicate that several of the recently described lemur species should be reevaluated with additional data and that the number of good species among the currently known taxa is probably lower than currently assumed.</p
A rapid assessment of waterbirds and the mangrove status in the Menabe Antimena Protected Area, Madagascar
No full textMangroves are of great ecological importance that provide multiple ecosystem services, shelter, and habitat for many threatened waterbird species. The mangroves of the Menabe Antimena Protected Area (MANAP) in western Madagascar are among the most extensive remaining on the island. The remaining dryland forests of the MANAP have been subjected to immense deforestation in recent years. Although remote sensing studies indicate that the mangrove forest loss is considerably lower than the dryland forest loss, little is known about the mangroves’ degradation status. Furthermore, detailed information on bird diversity and numbers is scattered, and previous surveys focused on northern parts of the MANAP, recently designated as the Wetlands of the Tsiribihina RAMSAR site. This study aims to assess bird diversity and abundance, as well as the status of mangroves in the MANAP. We conducted a rapid survey using direct observations at three sites along the coastal regions of the MANAP from 24 Sep–2 Oct 2019. We recorded 71 species of birds in the mangroves and coastal wetlands. High numbers of individuals were counted for several species. Numbers of the Madagascar Plover Charadrius thoracicus and the Madagascar Teal Anas bernieri fulfill criteria for important bird areas at single survey sites and the site is likely to be of importance for Madagascar Sacred Ibis Threskiornis bernieri; these three species are all globally threatened. Mangrove degradation is still limited, but numerous threats to mangroves are present. Our results highlight the importance of the mangroves of the MANAP for several endemic bird species in Madagascar. We provide recommendations for conservation management and future research
Phylogeographic analysis of the true lemurs (genus Eulemur) underlines the role of river catchments for the evolution of micro-endemism in Madagascar
No full textIntroductionDue to its remarkable species diversity and micro-endemism, Madagascar has recently been suggested to serve as a biogeographic model region. However, hypothesis-based tests of various diversification mechanisms that have been proposed for the evolution of the island’s micro-endemic lineages are still limited. Here, we test the fit of several diversification hypotheses with new data on the broadly distributed genus Eulemur using coalescent-based phylogeographic analyses.ResultsTime-calibrated species tree analyses and population genetic clustering resolved the previously polytomic species relationships among eulemurs. The most recent common ancestor of eulemurs was estimated to have lived about 4.45 million years ago (mya). Divergence date estimates furthermore suggested a very recent diversification among the members of the “brown lemur complex”, i.e. former subspecies of E. fulvus, during the Pleistocene (0.33-1.43 mya). Phylogeographic model comparisons of past migration rates showed significant levels of gene flow between lineages of neighboring river catchments as well as between eastern and western populations of the redfronted lemur (E. rufifrons).ConclusionsTogether, our results are concordant with the centers of endemism hypothesis (Wilmé et al. 2006, Science 312:1063–1065), highlight the importance of river catchments for the evolution of Madagascar’s micro-endemic biota, and they underline the usefulness of testing diversification mechanisms using coalescent-based phylogeographic methods
Toward Passive Acoustic Monitoring of Lemurs: Using an Affordable Open-Source System to Monitor Phaner Vocal Activity and Density
No full textAbstract Developing new cost-effective methods for monitoring the distribution and abundance of species is essential for conservation biology. Passive acoustic monitoring (PAM) has long been used in marine mammals and has recently been postulated to be a promising method to improve monitoring of terrestrial wildlife as well. Because Madagascar’s lemurs are among the globally most threatened taxa, this study was designed to assess the applicability of an affordable and open-source PAM device to estimate the density of pale fork-marked lemurs ( Phaner pallescens ). Using 12 playback experiments and one fixed transect of four automated acoustic recorders during one night of the dry season in Kirindy Forest, we experimentally estimated the detection space for Phaner and other lemur vocalizations. Furthermore, we manually annotated more than 10,000 vocalizations of Phaner from a single location and used bout rates from previous studies to estimate density within the detection space. To truncate detections beyond 150 m, we applied a sound pressure level (SPL) threshold filtering out vocalizations below SPL 50 (dB re 20 μPa). During the dry season, vocalizations of Phaner can be detected with confidence beyond 150 m by a human listener. Within our fixed truncated detection area corresponding to an area of 0.07 km 2 (detection radius of 150 m), we estimated 10.5 bouts per hour corresponding to a density of Phaner of 38.6 individuals/km 2 . Our density estimates are in line with previous estimates based on individually marked animals conducted in the same area. Our findings suggest that PAM also could be combined with distance sampling methods to estimate densities. We conclude that PAM is a promising method to improve the monitoring and conservation of Phaner and many other vocally active primates
True lemurs…true species - species delimitation using multiple data sources in the brown lemur complex
Full text linkBackground: Species are the fundamental units in evolutionary biology. However, defining them as evolutionaryindependent lineages requires integration of several independent sources of information in order to develop robusthypotheses for taxonomic classification. Here, we exemplarily propose an integrative framework for speciesdelimitation in the “brown lemur complex” (BLC) of Madagascar, which consists of seven allopatric populations ofthe genus Eulemur (Primates: Lemuridae), which were sampled extensively across northern, eastern and westernMadagascar to collect fecal samples for DNA extraction as well as recordings of vocalizations. Our data base wasextended by including museum specimens with reliable identification and locality information for skull shape andpelage color analysis.Results: Between-group analyses of principal components revealed significant heterogeneity in skull shape, pelagecolor variation and loud calls across all seven populations. Furthermore, post-hoc statistical tests between pairs ofpopulations revealed considerable discordance among different data sets for different dyads. Despite a high degreeof incomplete lineage sorting among nuclear loci, significant exclusive ancestry was found for all populations,except for E. cinereiceps, based on one mitochondrial and three nuclear genetic loci.Conclusions: Using several independent lines of evidence, our results confirm the species status of the members ofthe BLC under the general lineage concept of species. More generally, the present analyses demonstrate theimportance and value of integrating different kinds of data in delimiting recently evolved radiations
Complex social and political factors threaten the world's smallest primate with extinction
No full textWe highlight current problems, challenges and dilemmas of conservation action in Madagascar, which is one of the poorest countries, but also the hottest global biodiversity hotspot. Consequences of climate change and the COVID-19 pandemic exacerbate an already dramatic situation for many protected areas that are under pressure from illegal logging and habitat clearance for agriculture. The example of Madame Berthe's mouse lemur (Microcebus berthae), the world's smallest primate, illustrates how conservation efforts are failing because this “critically endangered” lemur species (Markolf et al. 2020) is feared to be extinct only 30 years after its discovery, even though its entire global range is situated inside a protected area. Numerous other lemurs, who have a higher percentage of CR/EN/VU species than any other group of mammals, are facing very similar prospects, despite this globally most endangered group of mammals enjoying particular attention from conservation policy makers and activists for decades because their endemic populations have been rapidly declining in shrinking habitats
Lemurs of the Beanka Forest, Melaky Region, western Madagascar
No full textExplaining the biodiversity and, in particular, the high levels of microendemism of primates in Madagascar has been a scientific challenge for many decades. A prerequisite to our understanding of lemur biogeography is high-resolution spatial data based on homogenous sampling effort across the island. Although the distribution of lemurs is comparatively well documented, some areas of Madagascar have been poorly surveyed. Among these zones is the large zone of microendemism between the Tsiribihina and the Betsiboka Rivers in western Madagascar. Here, we add new data on the distribution of several less known lemur species in this area. Two rapid lemur surveys in combination with hitherto unpublished information confirms the presence of at least 11 primate species from all five lemur families in the Beanka Forest - an isolated fragment of dry deciduous forest on limestone close to Maintirano. This level of species diversity is considerable and exceeds most other dry deciduous forests on the island. The specific determinations of Cheirogaleus sp. indet., Lepilemur cf. randrianasoli, Hapalemur cf. griseus ranomafanensis, and Mirza sp. in the Beanka Forest need to be supported by morphological and genetic data. Overall, lemur distribution in the surveyed zone of microendemism only partly supports the centers-of-endemism hypothesis. Given its extraordinarily high lemur diversity, the Beanka Forest deserves more attention from researchers studying lemur ecology and behavior. Current programs of Biodiversity Conservation Madagascar are important for the conservation of this forest area
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