热带雨林生物多样性保护与生物资源可持续利用研究

热带雨林被誉为地球的绿肺,其拥有丰富的植物、动物和微生物物种,对于全球生态系统的稳定和人类的社会经济发展至关重要。然而,不可持续的人类活动,如砍伐森林、非法采伐、土地转换和气候变化等,对热带雨林造成了严重的破坏和生物多样性丧失。为解决这些挑战,提出了一些可能的解决方案。基于此,对热带雨林生物多样性保护与生物资源可持续利用进行研究,以供参考。

Pollination Biology of Ficus hispida in the Tropical Rainforests of Xishuangbanna, China

Ficus hispida L. (Moraceae) is a remarkable species in the ecosystem of tropical rainforests in Xishuangbanna, China. The figs and fig_pollination wasps (Chalcidoidae: Agaonidae) are highly co_evolved mutualists that depend completely on each other for propagating descendants. Pollination of all fig species is done by fig wasps; their unique symbiotic associates, the fig wasps, cannot develop in anywhere except in the fig syconia. The present paper reports on the biology and flowering phenology of F. hispida , as well as the propagation character and pollination behavior of the fig wasps (Ceratosolen solmsi marchali Mayr) based on our observations in the rainforests of Xishuangbanna, southern Yunnan of China. F. hispida is a dioecious tree that annually blossoms and bears fruits 6-8 times, with four to five fruit_bearing peaks. The male trees produce pollen and provide fig wasps with reproductive havens, while the female trees produce fig seeds after pollination by the female wasps. Pollen of F. hispida cannot escape from the dehiscent anthers until they are disturbed by fig wasps. The female wasps open the anthers and collect pollen with their antennal scrapes, mandibles and legs, and then carry pollen to the female receptive syconia where fertilization takes place. Meanwhile, some of the female wasps lay eggs in the male receptive syconia. It takes about 3-67 min to search for the receptive syconia for pollination, and 15-23 h to enter the female receptive syconia. The number of female wasps entering a syconium has close relation with the impregnation and seed_bearing rate of female flowers, as well as the oviposition and reproduction rate of the fig wasps themselves. F. hispida is endowed with a relatively high level of seed bearing (54.1%-82.5%, average 73.8 %). The wasp oviposition rate on the male flowers is between 72.3% and 93.8% with a mean of 84.4%.

Impact of anthropogenic disturbance on species diversity and vegetation structure of a lowland tropical rainforest of eastern Himalaya, India

Impact of anthropogenic disturbance on species diversity and vegetation structure of a lowland tropical rainforest was studied in the foothills of Eastern Himalaya, India. Tree species richness,density, basal area and the diversity indices were found significantly(P<0.05) decreased with the increasing level of disturbances whereas, shrub density, basal area and herb density significantly increased with increasing disturbance level. In case of shrubs, Simpson's dominance index significantly(P<0.007) increased along the disturbance gradient,whereas Pielou's evenness index significantly(P<0.005) decreased with an increasing level of disturbance. Shannon-Weiner diversity index for herbs significantly(P<0.016) increased with increasing disturbance whereas, Simpson's dominance index was significantly(P<0.013) declined along the disturbance gradient. Results revealed that10-50 cm dbh classes constituted the highest stem density, and highest basal area was recorded in the >100 cm dbh class in all three sites. Density of the matured trees decreased with increasing DBH whereas, tree basal area tended to increase with increasing DBH in all three sites. Tree species richness was highest in the lower DBH classes.62.07% of the total tree species regenerated in the largely undisturbed site followed by 50% in the mildly disturbed and 26.32% in the highly disturbed site.The overall regeneration condition was found to be good in the largely undisturbed site. Mildly disturbed site exhibited fair regeneration and so was in the highly disturbed site. Discernable variations in species composition, diversity, regeneration and tree population structure revealed the impact of anthropogenic disturbances on rainforest vegetation dynamics. Higher degree of disturbance was furtherly found not only affecting species diversity but also promoting the growth of invasive weed species.Dominance of Hydnocarpus kurzii and Crypteronia paniculata in the highly disturbed site also indicated that these less-valued timber species may benefit from the vegetation mosaic produced by the disturbance; so differences in abundance of these species may be useful for bio-indication. Furthermore,present study suggests the need of adequate biodiversity conservation measures and adaptation of sustainable forest management approaches in disturbed areas of lowland tropical rainforest in the foothills of eastern Himalaya, India.