| Habitat desertification significantly affected food composition of lizard and gradually reduced the type of foraged food.This study worked at Kubuqi desert in Ordos of China in 2016-2017 and studied the food habits of lizards using stomach dissection.Stomach contents of 425 lizrads from three sample fields(fixed dune,semi-fixed dune,mobile dune)were analyzed including 294 toad-headed lizard(Phrynocephalus frontalis),82 multiocellated racerunner(Eremias multiocellata)and 49 mongolian racerunner(E.argus).The diet of lizard through stomach contents analysis and counts the contents(their food quantity and frequency)respectively.Analyzing diversity index,nutritional niche breadth,Simpson index and Pielou evenness index.The main results are as follows:(1)Comprehensive two-year experimental data of toad-headed lizards,we found 3 classes 11 orders and 42 families in their stomachs.In addition,also found a small amount of plant debris(1.89%)in the stomach contents.This result shows toad-headed lizard in the Erdos region is an omnivorous animal mainly preys arthropods(98.11%)and eats a very small number of plants.There was a significant differences in the types of food between different years(x2 = 740.90,df = 50,P<0.0001),and Formicidae were the main items in the diet of toad-headed lizards.The type of food in the stomachs were not related to the year,but affected by the changes of the habitat environment,it showed that the predation species gradually decreased with desertification(fixed sand dune>semi-fixed sand dune>mobile sand dune).The food dissimilarity index between fixed dune and semi-fixed sand dunes was small,but the food differences between mobile dunes and other two types of dunes were relatively large.Habitat desertification significantly affected food composition of toad-headed lizard and in different habitats there was a Significant differences in food composition in 2016(?2 = 138.91,df= 78,P<0.0001)and 2017(?2 = 2256.92,df= 82,P<0.0001).(2)The gastric contents analysis and available food statistics of multiocellated racerunner in different habitats showed that habitat desertification significantly affected food composition of multiocellated racerunner.The food composition of animals was gradually decreased and the food composition also significant different(?2 = 50.98,df = 32,P<0.005).The decrease in food resources was one of the most important causes of changes in the diet of lizards.Although the intragastric food species of the iridothornis in semi-fixed sand dunes was less than fixed dunes,the trophic niche breadth(7.2979)and evenness index(0.7581)were higher than that of fixed sand dunes(5.1138 and 0.6726,respectively).Multiocellated racerunner on the sand dunes was wider and more uniform than the fixed dunes in the range of feeding,so that sufficient food can be obtained in harsh environments.(3)Researched the food habits of E.argus using stomach dissection and 2 classes 9 orders and 22 families were identified in its stomach.The mongolian racerunner preferred insect which accounted for 93.36%of all the food items,and it also prey some arachnids(6.64%).Aphididae was its main predation target,and formicidae,lepidoptera larvae,and arachnids also had a relatively higher predation rates.(4)The food preference index provides a good help for us to understand the nutritional status of predators and the use of resources in the environment.Lizards in different habitats also differ in the type of food they prefer and the degree of preference has also changed greatly.The main reason for this result was the depletion of food resources in the desertification environment In order to better adapt to the environment,lizards began to feed on foods that were previously non-selective or even unfavorable. |
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