No abstract

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The monthly daytime and night-time diet, activity and feeding height of an habituated black lemur group were compared by ‘auditory group sampling’ for a total of 561 daytime hours and 472 night-time hours in Lokobe Forest, Madagascar. Both the daytime and night-time diets were dominated by fruit, but the former was more diverse than the latter and included more leaves. Some food items were eaten mainly or solely at night or during the day. The proportion of total time spent feeding was variable and was lowest between March and June, coinciding with a dearth of ripe fruit. The proportion of night-time spent feeding exceeded the proportion of daytime spent feeding during August, September, October and December. The group fed more frequently in the undercanopy during the day and the canopy during the night. The ratio of time spent feeding to time spent travelling was significantly smaller during the day compared to the night. These differences can be best explained by the group preferring to feed in the undercanopy during the day and the canopy at night.

I describe the fruit characteristics of species closely associated with black lemur seed dispersal (i.e., species that are often dispersed by die black lemur and only dispersed by the black lemur in die Lokobe Forest). A black lemur group was habituated and observed during the day and night for all months of die year (total 1272 h). When fruits were eaten, die plant species was identified, die maturity of the fruit and treatment of the seeds noted, and the fruit described in terms of ripe fruit color, husk thickness, fruit length, and seed length and width. Black lemur feces were searched for seeds; these were identified and signs of damage noted. Other potential dispersers feeding on the fruits of species eaten by the black lemur were also noted. The black lemurs were seen eating die fruits of 70 species. Of these, 51 species were defined as closely associated with black lemur dispersal and 16 species had seeds that were either often preyed upon or wasted by the black lemur, or were seen being eaten by other potential seed dispersers. Fruits of species in the former group were often dull colored (94% of species); rarely less than 1 cm long (6%); rarely had seeds less than 0.1 cm long or less than 0.1 cm wide (2 and 4%, respectively); never had seeds more than 4 cm long or greater than 2 cm wide; and quite often had either thick husks (49%) or thin husks (51%). In contrast, the fruits of the latter group were often brightly colored (75% of species) and nearly always had a thin husk (94%). Also, this latter group included more small and very large fruits and seeds than the former group. Fruit characteristics significantly associated with the former group were: dull color, thick husk, fruit length greater than 2 cm, seed length 1–4 cm, and seed width 1–2 cm. The extent to which these traits are the result of coevolution between plants and the guild of lemur dispersers that includes the black lemur is not clear, but a coevolved lemur–fruit syndrome remains a possibility. RESUMES Cette étude porte sur la description des caracteristiques des fruits appartenant aux espèces dont la dissemination des graines est étroitement liée au Eulemur macaco. Ces espèces sont definies comme étant souvent disséminees par E. macaco et uniquement disséminées par E. macaco dans la for○t de Lokobe. Dans le but d'identifier ces espéces, un groupe de E. macaco a été habituéà la présence humaine et observé jour et nuit pendant tous les mois de 1'année (en total 1272 h). Une fois le fruit consommé, I'espèce était identifyée, la maturityé du fruit ainsi que le traitement de la graine notés et le fruit était dàcrit en termé de couleur á maturityé, d'épaisseur de I'enveloppe, de longueur de fruit et de longueur et de largeur de graine. Par la suite, les féces sont recherchés afin d'identifier les graines qu'ils contiennent et routes signes d'endommagement de celles‐ci sont notés. Les autres agents de dissémination potentiels, consomma‐teurs des fruits appartenant aux espèces consommées par E. macaco, ont étéégalement notés. Les E. maca...

Primates are known to be important in dispersal of seeds of tropical rainforest trees, but their role in pollination is very poorly documented. Although the ‘traveller’s palm’ Ravenala madagascariensis is widespread, only a single well-documented report exists for its pollination by Malagasy prosimians. Black lemurs, Eulemur macaco, exploit nectaries of Parkia as well as Ravenala systematically at the massifs of Ambato and Lokobe, and almost certainly contribute substantially to their pollination, confirming a proposal first made by Sussman and Raven [Science 1978;200: 731–736].

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.

In order to classify trees in the Lokobe Forest, Nosy Be, as dispersed, possibly dispersed, or not dispersed by Black Lemurs (Eulemur macaco), two Black Lemur groups were habituated and observed during the day and night for all months of the year (total 1219 hours). When fruits were eaten, the species was identified, and the maturity of the fruit and treatment of the seeds noted. Black Lemur droppings were searched for seeds; these were identified and signs of damage noted. Species that had ripe fruit that were not eaten by the Black Lemur were also identified, as were fleshyfruited species that produced little or no ripe fruits during the study. Other frugivores feeding on the fruits of black lemur-dispersed species were also noted. In order to estimate the proportion of tree species, tree trunks, and trunk basal area in the Lokobe Forest dispersed, possibly dispersed, and not dispersed by Black Lemurs, plots were installed in Lokobe's two forest types and the trees they enclosed were identified and their dbh measured. For the slope forest Black Lemurs dispersed 57% of the represented tree species, 71 % of the represented tree trunks, and 73% of the represented trunk basal area. For the ridge forest these values were 49%,76%, and 88% respectively. Only four of the 38 black lemur-dispersed species had fruits that were also eaten by other frugivore species. These results show that the Black Lemur is very important for seed dispersal in Lokobe Forest.

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