ON THE TREND OF POPULATION DYNAMICS IN GIANT PANDA BASED ON AGE STRUCTURE

The Giant panda (Ailuropoda melanoleuca) is a precious endangered animal well-known in the world. Great attention has been paid to its studies. The population dyn-amics is concerned widely, bat it is difficult to study. However, Hu (1987) has repo-rted recently an age structure of the Giant panda's living population at Wu-yi-peng, Wolong Nature Reserve which makes us possible to study the trend of the development of this population. Hu's original data were adjusted to age classes of 3 years (tab. 2). The average numbers of cubs given by one Giant panda in each age class were estimated, and the survival rates from each age class to the next one were calculated (tab. 3). By"Leslie Matrix" (tab. 4), the age structures and the population numbers were predicted to the year of 2011 (tab. 5, fig. 1), and the conclusions approached are as follows: (1) The Giant panda's population at Wu-yi-peng, Wolong Nature Reserve is considerably stable, its development is rather slow. Up to 2011, or 33 years later,there will be only 42.61 individuals,increasing by 13.61 pandas or 46.93% or compared with the number of 1978, that means to increase by 0.977% yearly. Observing the data in detail, a population decrease in the early period from 1981 -1990 has been seen. The cause we ascertained is the unreasonable age structure of 1978, the figure of 3-5 year group was too low, less than that of the succeeding groups. It is possible that in tht year about 1975, some accidents might happen such as indiscriminate hunting or capturing alive for the zoos, etc. From the predicted age structure by Leslie Matrix, it will be normal only up to 1996, that is the structure, being in the form of a pyramid. The population will increase a little, faster during the 12 years 1999-2011. The individuals increase by 7.65, or 21.86% of the 1999's population, yearly increasing rate is 1.66%. ( 2 ) According to the nature of Leslie Matrix, the population number should in-crease geometrically or in multiple which is a constant, it is true in the data after 1999, the multiplication number is about 1.05. The yearly increasing rate will be 1.64% which is the same basically as compared with the above datum 1.66%. Any- way, the population is increasing at an exceedingly low speed, but it is luck enough so long as it is increasing. It is a consolation to the people being concerned about this endangered animal. ( 3 ) Mr.Wei worked out that the innate increasing capacity of t e Giant panda's population r = 0.0055688, if calculated by the formula N = Noert, the number from 1999 to 2011 should be increasing to 34.85 individuals, lower than out above figure. (4 ) Wu-yi-peng is one of the best ecological environments for Giant panda, and the protective measures are the most effective, the Giant panda's population there, is so feeble that any slight destruction will cause it a difficult development for ten years. In other places where the habitats are not so agreeable as Wu-yi-peng, or the protective measures are not so effective, any slightest catching will make the popul-ation difficult to recover. Therefore, the service of Giant panda's protection must be strengthened and the protective measuies must be set elaborately as well.