Effects Of Habitat Desertification On Lizard's Community Composition And Reproductive Output

From May to September,2016,we selected three different types of habitats with different stages of desertification in the Erdos region of Inner Mongolia,China,and then investigated the community composition of lizard and some habitat characteristics by line transect method.From May to September,2017,a number of pregnant female lizards of Phrynocephalus frontalis,especially those in their late pregnancy from the three habitats,were captured and brought to the laboratory for rearing,until their hatchings hatched from the eggs.So that we could study the effects of habitat desertification on the reproductive output of lizards.The research results showed that:1.The total numbers of lizards found in the three types of habitats(Fixed dune,Semi-fixed dune,Mobile dune)were 2097,1377,904 respectively,and the community composition of lizard was statistically significant among the three habitats(x2=763.09,df=4,P<0.01).2.There were three kinds of lizard species found in Fixed dune,namely P.frontalis,Eremias multiocellata and E.argus,the numbers of the three lizard species found were 1230,668,199 respectively,and the corresponding quantitative proportion were 58.65%,31.86%,9.49%.In Semi-fixed dune,there were only two kinds of lizard species:P.frontalis and E.multiocellata,the numbers of which were 1217,160 respectively,and the corresponding quantitative proportion were 88.38%,11.62%.There were only two kinds of lizard species in Mobile dune,too.We found that the quantitative proportion of P.frontalis was abnormally high(up to 99%),while the individuals of E.multiocellata had rarely been seen in such kind of habitat.3.From Fixed dune,Semi-fixed dune to Mobile dune,with increasing desertification of habitat,the richness,Shannon-Weaver diversity index,Pielou's evenness index and Simpson's diversity index of lizard community gradually decreased significantly.4.The results of Canonical Correspondence Analysis(CCA)showed that the main factors affecting the community composition and population size of lizard included vegetation height,bare ground percent,shelter percent,water content of surface soil and porosity of surface soil.In general,P.frontalis preferred the areas dominated by bare ground,while E.multiocellata preferred the region with sufficient shelter and loose moist soil.As for E.argus,individuals of this kind of lizard species were frequently found in habitats with high vegetation.5.The mass and snout-vent length of these female lizards of P.frontalis differed significantly among the three habitats,while the tail length of lizards was not significant.6.Eggs of lizards from Fixed dune had the longest duration of incubation,which lasted about 40 days,while those eggs of lizards from Semi-fixed dune and Mobile dune had similar duration of incubation(about 34 days),which was 6 days shorter than that of lizards from Fixed dune.With increasing desertification of habitat,the average number of eggs of P.frontalis decreased,and the duration of incubation of eggs shortened,while the hatching success rate of eggs increased.7.The hatching success rate of eggs of lizards from Mobile dune was the highest,up to 62.71%,and that of eggs of lizards from Semi-fixed dune is the second highest,about 54.55%,while eggs of lizards from Fixed dune had the lowest one,which was as low as 47.12%.The reproductive output of P.frontalis was statistically significant among the three habitats.