Study On Population Ecology Of Tsinling Tree Toad (Hyla Tsinlingensis)

Amphibians have high ecological environmental value,which can not only affect the ecological balance,but also reflect the environmental quality of their habitats,and are often regarded as an important indicator group of environmental health.Amphibians have been affected by human activities and global changes in recent years,and their habitat degradation,loss and dysfunction have become increasingly prominent,which has severely affected their population structure and ecological functions.The genus Hyla,which has 38 known species currently.Of the 8 species found in China,tsinling tree toad is endemic to Qinling Mountains.Since it was first recorded in Gansu Province in 1964,there has been a lack of systematic research on population ecology.Accordingly,in this study,a survey on population ecology of tsinling tree toad was conducted from the end of May to September 2020,in Kang County,Gansu Province.The data obtained can also fill the gaps in the life history of tsinling tree toad and provide basic data for subsequent ecological research and the protection of this specie.During the study,the population ecology of the tsinling tree toad was studied by combining the sample method,direct counting method,correlation test,variance analysis,principal component analysis and linear regression analysis.The main results of the study are as follows:(1)A total of 203 adult tsinling tree toad(146 ?,57 ?)were captured in the wild.The results showed that the average body length of male was 41.55 mm ± 0.18 mm,while the female's average body length was 46.40 mm ± 0.26 mm by measuring the14 morphological characteristics.The average body length ratio of female to male was1.117,and the heterosexual index was 0.105.There were significant differences between male and female in diameter of tympanum,diameter of eye,head length,internasal space,diameter of lower arm,tibia length,leg length(P < 0.05).There was no significant difference in head width,snout length,interorbital space,tibia width,foot length(P > 0.05),which is in line with the fertility hypothesis.(2)The population and density of tsinling tree toad varied greatly in different sites and months.The population and density of tsinling tree toad were the largest in Lijiagou plot,followed by Doubahe plot,and the smallest in Yuanjiagou plot.The occurrence rate of tsinling tree toad is highest in June and July.Tsinling tree toad is a strict nocturnal animal.The ratios of females to males were 1:2.56 during the breeding period,which is also in line with the conclusions of the existing research on sex ratio of frogs.The average snout-urostyle length and body mass are the largest in July.The relative fatness was different between June and August and between male and female(P < 0.05).(3)It was the only species with a monosyllabic call by analyzing the recordings of 42 male tsinling tree toads.The relationship between the call dominant frequency and the morphological characteristics was analyzed,and it was found that the call dominant frequency was negatively correlated with head length,leg length and snout-urostyle length.The snout-urostyle length were positively and negatively correlated with call duration and t call numbers,respectively.The brood amount of female tsinling tree toad was mainly positively correlated with snout-urostyle length and body mass.Females may increase their abdominal capacity by increasing their body size to store more energy and promote the production of more eggs.(4)The eggs of the tsinling tree toad could hatch after 3 to 4 days at room temperature.It was found that the inhibitory effect of density on tsinling tree toad tadpoles mainly occurs in the late stage,not the early stage through density control experiments.The main reason may be the early tsinling tree toad tadpoles was small individuals and weak intraspecies competition;as the individuals grow,the demand for resources increases,which produces a negative density effect.(5)It showed that tsinling tree toad preferred to inhabit in low shrubs,vegetation coverage,high atmospheric humidity,hydrostatic type,close to farmland habitat by analysing habitat preference coefficient.It showed that the habitat selection of tsinling tree toad was mainly affected by vegetation factor,temperature factor,water factor,food factor and human disturbance by principal component analysis.