The Studies On Food Sources And Trophic Levels Of Cave Terrestrial Animals Using Stable Isotopes

The food source,trophic level and food web structure of cave animals are important contents on study of animal ecology.On October 2016,the investigation and research on the terrestrial animals in Shuijiang cave,Longgong cave and Shuanglong cave in Yuping Town of Libo in Guizhou Province were carried out,and analyzed the dynamic change of ?¹³C and ?¹⁵N in light zone,weak-light zone and dark zone with the terrestrial animal and organic carbon source.using stable carbon and nitrogen isotope method,explores the contribution of the cave the organic carbon source on terrestrial animal food sources,estimation of cave terrestrial animal trophic level and set up a simplified food web model of Guizhou Libo Yuping Town,the cave of the terrestrial ecosystems.In order to understand the status and role of the animal in the cave ecosystem,would provide basic information to enrich the domestic research cave ecosystem information database,and help us to understand the characteristics and process of cave ecosystem.The results are as follows:A total of 701 animals were collected,accounting for 59 species,39 families,17 order,8 class,4 phylum.Among them,there are 306 animals in Shuijiang cave,total 30 species;Longgong cave hole 116,total 21 species;Shuanglong cave 279,total 29 species.By analyzing the dynamic change of ?¹³C and ?¹⁵N of cave plants,soil organic matter and animal samples,it is concluded that:?1?The values of ?¹³C and ?¹⁵N were different in the same species in different caves or in different caves.The ?¹³C in the cave was low in the range of-38.25 ± 0.95 ‰ to-29.44 ± 0.49 ‰,which was lower than that of the plant.?2?The soil organic matter ?¹³C and ?¹⁵N values of different light zones in the same cave were different,and the values of soil organic matter ?¹³C and ?¹⁵N were different in different caves and same light zone.The ?¹³C?-32.73 ‰ ^-24.68 ‰?and ?¹⁵N?-2.12 ‰ 5.67 ‰?in the cave soil organic matter were lower than those of the soil organic matter ?¹³C?-25 ‰ ^-22 ‰?and ?¹⁵N?mean value 7.30 ‰?.In addition,the ?¹³C value of organic matter in light zone soil was not in the range of ?¹³C of plant samples,indicating that the contribution of cave vegetation to soil organic matter was smaller.?3??¹³C and ?¹⁵N values were different for animals in the same cave and different light belts,as well as the same group of animals in different caves or different light belts.The contribution of organic carbon source on the food sources of cave animals was calculated by IsoSource software with Multiple linear mixed model,which showing that the soil organic matter on food source contribution of animals was higher than those in plants.The cave terrestrial animal nutrition level was estimated by trophic level formula and the simplified food web model was built in Yuping Town of Libo in Guizhou.Conclusions are as follows:?1?Cave terrestrial animals have different levels of trophic in different cave ecosystems.Species of carnivorous Scutigeridae in cave ecosystem was relatively stable,and the trophic levels of the dark zone of the Shuijiang cave,the weak-light zone of the Shuanglong cave and the dark zone of the Shuanglong cave are 2.53,2.67 and 3.46,at third trophic level.The trophic levels of the highest mammal bats are not at the top of the cave ecosystem,but at the third trophic level.There are some differences in trophic position with a kind of animal in the same cave or cave with a different band of different band located,some even with more than 2 trophic levels.Such as rhaphidophoridae in Shuijiang cave dark zone in the second trophic level?2.32?,in the Longgong cave dark zone is located at the fourth trophic level?3.74?.?2?The terrestrial ecological system was composed of 5 trophic levels: The soil organic matter and plants are the first trophic level,of which the soil organic matter on food source contribution of animals was higher than those in plants.Cyclophoridae,Corrillidae,Bradybaenidae,Subulinidae,Canaenidae,Lymnaeidae,Cambalidae,Cambalopsidae,Paradoxosomatidae,Tipulidae,Theridiidae,Tetragnathidae,Salticidae,Agelenidae,Mimetidae,Araneidae,were the second trophic level,were primary consume;The third trophic level includes Myrmeleontidae?larva?,Scutigeridae,Pimoidae,Uloboridae and Bat class as the secondary consumer;Sicariidae,Podoctidae,Sparassisae were the fourth trophic level;Amaurobiidae were the fifth trophic level and top of the food chains.