Habitat use by endemic and introduced rodents along a gradient of forest disturbance in Madagascar

We used logistic and Poisson regression models to determine factors of forest and landscape structure that influence the presence and abundance of rodent species in the rain forest of Ranomafana National Park in southeastern Madagascar. Rodents were collected using live-traps along a gradient of human disturbance. All five endemic rodent species (Nesomys rufus, N. audeberti, Eliurus tanala, E. minor and E. webbi) and the introduced rat Rattus rattus were captured in both secondary and primary forests, but the introduced Mus musculus was only trapped in secondary forest. The abundance of R. rattus increased with the level of habitat disturbance, and it was most common in the heavily logged secondary forest. Furthermore, the probability of the presence of R. rattus increased with decreasing distance from forest edge and decreasing canopy cover, while the probability of presence increased with increasing herbaceous cover, altitude and overstory tree height. The species was never observed farther than 500 m away from human habitation or camp-site. N. rufus prefered selectively-logged forest at altitudes above 900 m a.s.l. Its probability of presence increased with increasing canopy cover, herbaceous cover and distance from forest edge, and with decreasing density of fallen logs, overstory tree height and distance from human habitation. N. audeberti prefered heavily-logged areas, while E. tanala was the only species occurring along the entire range of forest disturbance. We suggest that in the Ranomafana National Park the spread of R. rattus is associated with deforestation.     

Characterization of 13 microsatellite marker loci in Verreaux's sifaka (Propithecus verreauxi)

The Verreaux's sifaka (Propithecus verreauxi) is one of the species of Propithecus, living in the dry forest of southwest Madagascar. This species is endangered due to the loss and fragmentation of its natural habitat, a consequence of deforestation. Thirteen novel nuclear microsatellite loci were isolated and characterized in three populations of Verreaux's sifaka. The marker suite proved informative with an average of 8.9 alleles per locus and observed heterozygosity across the three populations of 0.675.     

Characterization of 21 microsatellites developed from Propithecus deckeni deckeni

Decken's sifaka (Propithecus deckeni deckeni) is found between the Mahavavy and Manambolo Rivers, in western Madagascar. Twenty‐one polymorphic nuclear microsatellite loci were isolated from genomic DNA derived from a P. d. deckeni, from Tsingy de Bemaraha National Park. Population genetic parameters were estimated on 10 individuals each, sampled from Tsingy de Bemaraha National Park and Tsiombikibo Classified Forests. Significant null alleles were detected in seven loci which were dropped before population genetic parameters were re‐estimated and compared to the full marker suite.     

Characterization of twenty-one microsatellites developed from <Emphasis Type="Italic">Propithecus diadema</Emphasis>

Diademed sifaka (Propithecus diadema) distributed throughout Madagascar’s eastern rain forests from the Mangoro and Onive Rivers north to the Mananara River. Twenty-one polymorphic nuclear microsatellite loci were isolated from genomic DNA derived from a P. diadema, from Mantadia National Park. Population genetic parameters were estimated on 10 individuals each, sampled from Mantadia National Park and Maromizaha Unprotected Forest. Allele sizes ranged from 4 to 14 and observed heterozygosities ranged from 0.200 to 0.900 per locus. This marker suite will be informative in further population genetic studies.     

Sampling Effects on Food Availability Estimates: Phenological Method,Sample Size,and Species Composition1

It is currently recognized that the method used to collect phenology data can affect the resulting pattern. However, to date, the underlying influences have not been examined. To examine potential methodological biases, we investigated the effects of phenological method, sample size, and species composition on phenological patterns using data collected to estimate food availability for three primate species in Ranomafana National Park, Madagascar. Two phenological methods were compared: selected tree observations and systematic transect monitoring. By generating bootstrapped subsamples derived from the transect tree data set, we simulated two selected tree data sets and subsequently compared the observed and bootstrapped values. Although the observed values fell within the bootstrapped confidence inrervals, suggesting no significant effects of sampling protocol or sample size, additional lines of evidence suggest otherwise. Observed samples composed of different plant species, whether based on species attributes such as life-form or categories such as food versus nonfood plants, consistently produced different phenological patterns. Wide confidence intervals of the bootstrapped samples indicate high individual variation in reproductive activity within the species sampled. Finally, we compared how well the selected tree and the transect methods represented food items used by all three primate species studied and found that transect methods sampled a wider diversity of food items, including rare foods, and a higher percentage of main primate food items than selected tree methods.     

Characterization of 21 microsatellite marker loci in the silky sifaka (Propithecus candidus)

The silky sifaka, Propithecus candidus, considered one of the rarest and most endangered primates in the world, exists in only a few fragmented forests in northeastern Madagascar. This species faces increasing pressures as a direct result from loss of habitat in the form of tavy (slash and burn agriculture), illegal logging and mining along with hunting for subsistence, even within protected areas. We report a marker suite of 21 loci developed from genomic DNA from a silky sifaka collected in 2003 from Anjanaharibe-Sud Special Reserve. Polymorphism of each locus evaluated in 18 individuals pooled from Marojejy National Park and Anjanaharibe-Sud Special Reserve. The number of observed alleles per locus ranges from 2 to 7. The observed and expected heterozygosity were 0.389–0.889 and 0.322–0.789, respectively. The information revealed in this study will provide useful tools for further study of the social structure and population dynamics of the silky sifaka to facilitate conservation management in the imminent future.     

Global climate cycles and cyclones: consequences for rainfall patterns and lemur reproduction in southeastern Madagascar

Most studies that examine the influence of climatic change on flora and fauna have focused on northern latitudes; however, there is increasing recognition that tropical regions are also being affected. Despite this, regions such as Madagascar, which are rich in endemic biodiversity but may have low adaptive capacity to climatic change, are poorly represented in studies examining the effects of climate variability on biota. We investigated how El Niño Southern Oscillations (ENSO) influence precipitation patterns in the rainforest region of southeastern Madagascar (1962–2006) and then constructed models to assess the potential contribution of climatic variables on the reproductive parameters of the Milne Edward's sifaka, a threatened lemur species (Propithecus edwardsi), over a 20‐year period. The Southern Oscillation Index of sea surface temperature (SST) anomalies in the tropical Pacific was associated with precipitation patterns including wetter wet seasons during warmer phases and drier dry seasons following cooler phases. The best‐supported models of lemur fecundity (female offspring per female that survive to 1 year of age per year) included cyclone presence during gestation and ENSO phase before conception and during the first 6 months of life. Models also suggested that heavy rains during gestation may limit birth rates and that prolonged drought during female lactation may limit first year offspring survival; although these variables were given little importance for predicting overall fecundity relative to ENSO phases and cyclone presence. Our results linking lemur reproduction with climatic variability suggest that climatic changes may be an additional threat to Madagascar's unique and already endangered flora and fauna. The association between precipitation in southeastern Madagascar and SST anomalies in the tropical Pacific suggests that dynamics of wildlife populations even in tropical areas such as Madagascar can be affected by global climate cycles making them potentially vulnerable to global climate change.     

Characterization of 20 microsatellites marker loci in the golden-crowned sifaka (<Emphasis Type="Italic">Propithecus tattersalli)</Emphasis>

The golden-crowned sifaka (Propithecus tattersalli) is one of the most critically endangered species of Propithecus endemic to a limited area in the Daraina region of north-eastern Madagascar. This species is endangered due to habitat loss and fragmentation, a consequence of deforestation. Twenty nuclear microsatellite loci were isolated from genomic DNA derived from a Propithecus tattersalli from the Daraina area in north-eastern Madagascar. Population genetic parameters were estimated on 20 individuals from two Daraina forest fragments to determine the potential utility of this marker suite for future studies on the golden-crowned sifaka.     

Quantitative variability of cyanogenesis in Cathariostachys madagascariensis—the main food plant of bamboo lemurs in Southeastern Madagascar

Giant bamboo (Cathariostachys madagascariensis) is a major food plant for three sympatric species of bamboo‐eating lemurs (Hapalemur aureus, H. griseus, and Prolemur simus) in the rain forests of southeastern Madagascar. This plant species is strongly cyanogenic. However, quantitative data on cyanide concentration in C. madagascariensis are scarce. Previous studies reported 15 mg cyanide per 100 g fresh shoot material (corresponding to approx. 57 µmol cyanide per gram dry weight). However, we found mean concentrations (±SE) ranging from 139.3±19.32 in ground shoots to 217.7±16.80 µmol cyanide per gram dry weight in branch shoots. Thus, cyanogenesis of C. madagascariensis was up to four times higher than reported before. In contrast to the strongly cyanogenic shoots no cyanide could be detected in differently aged leaves of C. madagascariensis confirming earlier studies. Within individual shoots fine‐scaled analysis revealed a characteristic ontogenetic pattern of cyanide accumulation. Highest concentrations were found in youngest parts near the apical meristem, whereas concentrations decreased in older shoot parts. Beyond the general intra‐individual variability of cyanogenic features analyses indicated site‐specific variability of both, the ontogenetic pattern of cyanide concentration as well as the total amount of cyanide accumulated in shoots. Additionally, analyses of soluble proteins—one important nutritive measure affecting food plant quality—demonstrated a converse quantitative relation of protein concentrations in leaves to cyanide concentration in shoots at the site‐specific level. We, thus, suggest integrative analyses on quantitative variation of cyanogenesis together with nutritive plant parameters in future studies. This approach would allow obtaining more detailed insights into spatial variability of giant bamboo's overall browse quality and its impact on lemur herbivores. Am. J. Primatol. 71:305–315, 2009. © 2009 Wiley‐Liss, Inc.