The daily activity pattern of wild adult Francois’ langurs (Trachypithecus francoisi francoisi) was observed in disturbed habitat at Mayanghe National Nature Reserve of Guizhou Province between 1999 and 2000. The behaviors of wild adult Francois′ langur were recorded at 5 minute intervals using an instantaneous sampling method. The results indicate that rest, forage, traveling, huddling, playing and grooming activities account for 35.41%, 31.67%, 14.44%, 9.61%, 8.54% and 0.33% respectively in the daily time budget of these wild adult Francois′ langurs during the study period. The majority of time is spent on resting and foraging, secondly on traveling, huddling and playing, and the least time on grooming.
In comparison with the results in undisturbed habitat, the time spent in resting is decreased while the time on other activities is increased. In the undisturbed habitat, vegetation is mainly secondary evergreen broadleaved mixed forests and is well protected. Food resources for wild Francois′ langur are rich and easy to obtain, including Rhur chinensis、Pistacia chinensis and Cyclobalanopsis glauca. Consequently the time spent in foraging in undisturbed habitat is decreased. In disturbed habitat, the natural forest is destroyed and replaced by dense shrubs, and the upper-slope is completely cultivated with farmland. This decreases food availability and changes the foraging behavior of the langurs, also causing a change of time budgets of other behaviors, such as increasing the proportion of traveling and decreasing the proportion of resting. At the same time, the fact that the frequency of human activity is higher in the disturbed habitat influences time budget of daily social behavior of the langurs including playing, huddling and grooming.
The patterns of activity rhythms of wild adult Francois′ langur in the disturbed habitat show some seasonal differences. Significant activity peaks are revealed in foraging and resting in all seasons, but peak values and duration are different. Proportion of traveling, playing and huddling are relatively low in all seasons. A daily rhythm of grooming appears in some seasons, but does not occur in other seasons. Duration and value of peaks reflect intensity of some behaviors in the rhythm, which corresponds to outside changes of conditions, such as temperature, illumination, food availability, human activity and so on. Therefore the pattern of activity rhythm of wild adult Francois′ langur is adaptable to change in the environment.
According to the results, some suggestions are given for long-term and efficient conservation of this endangered species in disturbed habitat. First, indigenous tree species and preferred vegetation of Francois′ langur should be restored. Secondly human activity, for example grazing, should be limited. Thirdly, building a bridge over bottom land could be considered to decrease the impact of human activity and for the convenience of human residents.