Primary Study On Seed Dispersal Effective Of Black-and-White Snub-nosed Monkeys In Mt. Lasha,Yunling Nature Reserve

Plant-animal interaction is the result of long-term coevolution,and seed dispersal is the research hotspot of plant-animal interaction.Seed dispersal is a process in which plant seeds break away from the mother tree and enter the suitable habitat for germination and growth.It is not only conducive to the dispersal of plants,but also conducive to the renewal of forest vegetation and the maintenance of biodiversity.Animal seed dispersal has important ecological service functions.Primates are one of the three types of seed communicators in forest ecosystem.However,the effectiveness of seed dispersal is lack of attention and evaluation.Therefore,there is a lack of awareness about the effectiveness of primate seed dispersal,especially the ecological service function of rare and endangered primate species distributed in temperate forest ecosystem.In this study,black-and-white snub-nosed monkey（Rhinopithecus bieti）,the flagship species distributed in temperate forest ecosystem,was selected as the research object to study the effectiveness of seed dispersal of R.bieti.This paper intends to solve the following three scientific problems:1)The plant species that can be dispersal in the digestive tract of R.bieti and their composition characteristics;2)Retention time and residual quality of seeds in digestive tract of R.bieti,and its influencing factors;3)Effect of seed dispersal of R.bieti on the distribution pattern of plant seedlings in overnight field.The behavior of wild R.bieti in Lasha mountain was directly observed through a single telescope,the behavior and feeding habits data of R.bieti were collected,and the plant species that can be transmitted in the digestive tract were determined by direct observation and fecal analysis during November 2018 to November 2019.Among them,13 plant species of R.bieti were observed by direct observation,belonging to 6 families and 8 genera;Through fecal analysis,18 morphological species of plants dispersal by the digestive tract of R.bieti were found,of which 9species have been identified,belonging to 5 families and 5 genera.The combination of direct observation and fecal analysis identified 14 plant species that can be dispersal in the digestive tract of R.bieti,belonging to 6 families and 9 genera,indicating that the digestive tract of R.bieti can dispersal plant seeds and has the potential of seed dispersal.In addition,based on the residue of seeds in feces,it is found that R.bieti can eat fruits falling from the ground in winter,which increases the cognition of the fruit eating proportion of this species,and provides a reference for comparing the effectiveness of seed dispersal of R.bieti in different seasons in the future.The retention time and residual quality of seeds in digestive tract of R.bieti in Tacheng cage were tested by feeding method during October 2021 to November 2021.The retention time and integrity rate of different seeds after passing through the digestive tract of R.bieti and the influence of seed size on the retention time and residual proportion were calculated.Four fruits that R.bieti like to eat were selected:Cotoneaster horizontalis Decne,Actinidia arguta,Sorbus scalaris Koehne and Sorbus megalocarpa Rehder were fed.The average retention time（MRT）of the four seeds in the digestive tract of R.bieti is 36.67±8.23 h（range:13.08-97.07 h）.Compared with the same genus of golden snub-nosed monkey（Rhinopithecus roxellana）（35 h）,the retention time of the seeds in the digestive tract of R.bieti is longer,which is in line with the hypothesis of digestive tract retention time and body shape.In the similar species groups,the smaller the size of mammals,the shorter the retention time in the digestive tract.There is a significant negative correlation between the seed volume and its residence time in the digestive tract of R.bieti（r=-0.696,n=12,P=0.012）.The smaller the seed volume,the longer the residence time in the digestive tract,which is consistent with the hypothesis of residence time and seed volume in the digestive tract of mammals.The speed of small seeds passing through the digestive tract is slower than that of large seeds.The average integrity rate of seeds passing through the digestive tract of R.bieti were 18.49%（6.67-33.33%）,which was like the residual proportion of seeds in the digestive tract of R.roxellana（19.7%）,but slightly less than that of macaque（23.1%）.Therefore,the results of residual proportion and retention time of digestive tract of R.bieti show that it can spread plant seeds far away and contribute to the renewal of vegetation in regional ecosystem.The species and quantity of non-native seedlings of R.bieti in the overnight and non-utilization area（control area）was collected by sampling method to explore the effect of seed transmission of R.bieti on the distribution pattern of seedlings in the overnight.There were significant differences in the species and quantity of non-native seedlings between the night land and the control land.The species and quantity of non-native seedlings in the night land were higher than those in the control land（species:z=-2.51,n₁=n₂=60,P=0.01;quantity:z=-2.38,n₁=n₂=60,P=0.02）;There was no significant difference between the non-native seed species in the soil seed bank of overnight and control plots（z=-1.27,n₁=n₂=20,P=0.21）;There was a significant difference in the number of non-native seeds in the soil seed bank of the overnight plot and the control plot（z=-3.52,n₁=n₂=20,P<0.01）.Within 150 m from the center point,the number of non-native seeds in the soil seed bank of the overnight plot was higher than that in the soil seed bank of the control plot.In the soil seed bank,the number of non-native Actinidia arguta in the soil seed bank of R.bieti were analyzed.It was found that there was a significant difference in the number of non-native Actinidia arguta in the soil seed bank of overnight and control sites（z=-2.98,n₁=n₂=20,P<0.01）.Within 150 m from the center point,the number of non-native Actinidia arguta in the soil seed bank of overnight sites was significantly higher than that of the control sites.The results showed that the seed transmission by R.bieti could increase the number of non-native seedlings and species in the overnight land,as well as the number of soil seed banks in the overnight land.This effect was particularly obvious within 150 m of the center point of the overnight land,and had a positive impact on the vegetation regeneration in the distribution area of the overnight land.Taking Yunling Nature Reserve in Yunnan Province and Baimaxueshan Nature Reserve in Tacheng of R.bieti as examples,this paper clarifies that R.bieti has the potential of seed transmission,obtains the residual proportion and retention time of plant seeds in the digestive tract of R.bieti,and preliminarily grasps the relevant indicators of the number and distance of seeds transmitted by R.bieti,and expounds the effectiveness of seed transmission of R.bieti and its ecological service function in the temperate forest ecosystem.Our results suggested that the protection of rare and endangered primates can be called for from the perspective of seed transmission and ecological service function.