Madagascar's ecosystems are subject to high levels of anthropogenic disturbance and stochastic events, including cyclones. We investigated the abundance of grayheaded lemurs (Eulemur cinereiceps) and vegetation structure in the fragmented forest of Manombo from 1995 to 2007, including 10 yr following Cyclone Gretelle in January 1997. We predicted that the density of this arboreal, frugivorous lemur would be similar in the pre-and post-cyclone intervals only if tree measures demonstrate trends toward recovery in the post-cyclone period. Initial impacts included severe damage to over 60 percent of trees. After 10 yr, all vegetation metrics except for stem density remained low relative to the pre-cyclone period, including dbh, height, and basal area. To investigate vegetation changes separately from cyclone effects, we compared forest structure in the pre-cyclone period alone. Basal area declined but dbh and stem density did not vary between 1995 and 1997; thus, anthropogenic activities or other factors did not consistently alter forest structure in this 2-yr period. Subsequent changes may be linked to cyclone response, presumably in synergy with human disturbance. Contrary to predictions, recent gray-headed lemur population densities were nearly identical to those recorded in 1995 (13.5 AE 3.2 vs. 13.6 AE 6.4 individuals/km 2 , respectively). Lemur populations may have remained stable or declined initially and then recovered in the last 10 yr. Life history and ecological adaptations may explain their resistance or resilience when faced with habitat change. Recent models suggest that lemurs have evolved in response to unpredictable environmental conditions. Such environmental variability may increase with projected climate change.

Population genetics and abundance of the Endangered grey-headed lemur Eulemur cinereiceps in south-east Madagascar: assessing risks for fragmented and continuous populations R i c k A . B r e n n e m a n , S t e i g E . J o h n s o n , C a r o l y n A . B a i l e y C h r i s t i n a I n g r a l d i , K i r a E . D e l m o r e , T r a c y M . W y m a n H u b e r t E . A n d r i a m a h a r o a , F i d i m a l a l a B . R a l a i n a s o l o J o n a h H . R a t s i m b a z a f y and E d w a r d E . L o u i s , J rAbstract Knowledge of both population size and genetic diversity is critical for assessing extinction risk but few studies include concurrent estimates of these two components of population biology. We conducted an investigation of population density and size, and genetic variation and past demographic events, of the Endangered grey-headed lemur Eulemur cinereiceps in south-east Madagascar. We estimated lemur density using line-transect surveys and used satellite imagery to calculate forest fragment area in three localities. We collected tissue samples from 53 individuals and used 26 polymorphic microsatellite loci to obtain measures of population structure (divergence and diversity) across these localities. We tested the probability of past bottleneck events using three models. Contrary to expectation, there were no significant differences in population density across localities. Genetic diversity decreased, but not significantly, with decreasing habitat area and population size. We found a higher likelihood of past bottleneck events in the fragmented coastal populations. The low population size and prior decline in diversity in coastal patches are consistent with their isolation, anthropogenic disturbance, and exposure to cyclone activity. The similarities in the estimates of density between continuous and fragmented sites may indicate recent population growth in the fragments but these populations nevertheless remain at risk from reduced levels of genetic variation. These patterns should be confirmed with more extensive sampling across the limited range of E. cinereiceps.This paper contains supplementary material that can be found online at