The Studies On The Food Web Structures And Trophic Relationships In Guizhou Shibingxia Cave And Mulaotang Cave By Means Of Stable Isotopes

Sel ected and observed the Shi bi ngxi a Cave and Mul aotang Cave which have vari ous speci es, Atotal of224sampl es fromShi bingxia cave were subordi nated to15speci es or groups,14families,11orders,6classes, Atotal of96sarrpl es from Mul aotang cave were subordi nated to10speci es or groups,10families,9orders,6classes, the dominant species of Shi bi ngxi a cave are Sypna sp. and Podoglyphiulus sinensis.the dominant speci es of Mul aotang cave are Glyphiulus valgatus and Distrammenasp. Accordi ng to the differentanimal species conposi ti on and quantity between two caves in Iight belts, we could divided alI the animals into6communities.That are community A Gastroptychia sp.+Podogl yphi ul us sinensis; community B: Sypnasp.+Ti pulidae sp.; community C: Sypnasp.+Podoglyphiulus sinensis; community D:Glyphiulus valgatus+Distrammenasp.; communi ty E:Distrammenasp.+Glyphiulus valgatus; community F: Opiliosp.+Distranmnasp.. According to the analysis of community diversity, the communities with the highest values of richness,diversity,maximum diversity, evenness, and dominance were A(2.5881), A(2.0868), A(2.1972), D (0.9610) and C (0.2791), and simalarity index(0.3571) of community E-F are the highest in these two caves.The results of correlation anlysis between community diversity and envoi ronmental factors showthat the content of SOMinsoil has the significantly positive correlati on with number of species, diversity and the biggest diversity of community (r=0.860,0.876,0.819); The pH value has the positive correlation with evenness(r=0.904); The air temperature(Ta) has the positive correlation with number of species(r=0.812), and has the positive significantly correlation with the diversity of community (r=0.928). So these results indictethat SOM, pH and Ta are the important factors that infIuence on the change of animal community diversity in these two caves.The δ13C value is commonly used for the anal ysi s of consumer food source. The δ15N value is commonly used to determine the Iiving creature position in the food web. The result shows that fauna enrichment on the δ13C and δ15N enrichment are obvious in Shi bingxia cave and Mulaotang cave. Two caves enrichment span on the δ13C(the difference between the maxi mumand mini mumval ues) is4.9114‰and6.2928‰respectively and on the δ15N is6.6870‰and5.0560‰. However, in generally, the two ecosystems enrichment on δ15N have a more stable than on δ13C So it is concluded that the two caves enri chment factors on the δ15N value are2.8080and2.4200respectively by using the Ievel δ15N value to evaluate the Ievel of nutrition. The trophic Ievels have three levels.They are as folIows, The first trophic level is soil organic matter.The second trophic level is Kronopolites sp., Gastroptychiasp. and Distrammenasp. which feed on soiI organic matter,The third trophic level is Oreolalax rhodostigmatus, spiders and bats taxa.The structure of food web shows that the energy source of the cave ecosytemmainly comes fromthe soil organic matters. Usually the animals at the top of the food chain prey the one towerd the bottom.Predation happens in the same Ievel of the food chain.For example, Kronopolites sp. could prey Gastroptychia, Sypnasp., Distranmnasp. although they are in the same trophic level.